Questions on Sludge

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source: Faxed Questions received during April 9, 1996

Cornell Waste Management Institute Videoconference

on Land Application of Sewage Sludges

As promised, here are some responses to questions concerning sewage sludge and its use on agricultural lands which were generated in response to a videoconference sponsored by the Cornell Waste Management Institute and Cornell Cooperative Extension on April 9, 1996. More than 75 questions were faxed in during the program (and others were received after the broadcast) and we were unable to answer more than a handful on the air.

In keeping with the mode of the video conference, rather than trying to make one answer to each question, we invited each of the panelists (listed below) representing very different points of view to answer. So far we have received responses from Jane Forste, Ellen Harrison and John Peverly. We have used their answers as they wrote them and identified the respondent by their initials. We expect additional responses from other panelists over the coming months, so please refer back to this list of questions and answers again to see what new information and opinion has been added.

We hope this is useful to you. For a copy of the videoconference on VHS tape, you can direct your order to: Rich Gray, Cornell Distribution Center, #8 Business & Technology Park, Ithaca, NY 14850; 607/255-2090, (fax 607/255-9946).

Panel Members:

Josh Cleland, Scenic Hudson, 9 Vassar St. Poughkeepsie, NY 12601
Jane Forste Wheelabrator/Bio Gro Division, 180 Admiral Cochrane Cr. Suite 305, Annapolis, MD 21401
Ellen Z. Harrison, Director, Cornell Waste Mgmt. Institute, Rice Hall, Ithaca, NY 14853
Elizabeth Meer, NYS Legislative Commission on Toxic Substances and Hazardous Wastes, 4 Empire State Plaza, 5th floor, Albany, NY 12248
John H. Peverly, Soil Crop and Atmospheric Sciences, 920 Bradfield Hall, Cornell University, Ithaca, NY 14853
Sally Rowland, NYS Dept. of Envir. Conservation, 50 Wolf Rd., Albany NY 12233
Edward Wagner, CH2M Hill, 99 Cherry Hill Rd., Suite 304, Parsippany, NJ 07054

Others Invited to Respond:

Charlotte Hartman, Citizen's Environmental Coalition
Nancy Kim, NYS Dept. of Health
George Lutzic & W. Michael Sutton, NYC DEP
John Walker, US EPA (4204), Washington, DC 20460

SLUDGE CHARACTERISTICS
1. What is the average nutrient content of sludges and sludge products? How does this compare to animal manures?

JHP. Dry wt. basis, nutrient content, %.

Source

N

P

K Sludge

5.6

2.7

0.12 "

5.2

2.3

0.28 Alkaline Stabilized

0.36

0.2

1.1 "

0.94

0.5

0.2 Composted

2.0

0.4

0.15 "

2.6

2.0

0.18 Dried, Pelleted

4.5

2.8

0.12 Dairy manure

0.2 - 0.5

0.1 - 0.2

0.2 - 0.6

GNL/WMS. The following table breaks down the average nutrient content of various types of manure, New York City biosolids, and New York City pellets derived from biosolids.

Source

TKN

(%)

NH3

(%)

P

(%)

K

(%)

Fe

(%) NYC biosolids

5.11

0.89

1.79

0.12

2.79 NYC pellets

4.41

0.60

1.80

0.10

2.04 Dairy manure

0.50

NA

0.21

0.40

NA Beef manure

0.57

NA

0.42

0.48

NA Swine (nursery) manure

0.69

NA

0.54

0.54

NA Sheep manure

1.13

NA

0.38

0.98

NA Goat manure

1.10

NA

0.27

0.76

NA Poultry (broilers) manure

1.67

NA

0.84

0.63

NA Turkey manure

1.19

NA

1.04

0.85

NA Horse manure

0.61

NA

0.23

0.45

NA
NA - data not available

The biosolids concentrations are based on a flow weighted average of the concentrations from each of the eight dewatering facilities from July 1992 to February 1996. The pellet concentrations are based on an arithmetic average of analyses from July 1993 to December 1995. The manure concentrations were taken from the Livestock Waste Facilities Handbook.

2. How does sludge compare to manures in structural composition (ie. crude fiber, other fiber) relating to improvement of soil tilth and water holding capacity?

JHP. For the same dry tonnage applied, sludge and manure physical effects on water-holding capacity, etc. Would be similar. If the manure had a high content of identifiable straw stems, effects would be delayed for a few weeks after application.

3. How do the metals concentrations in soils compare to metals concentration in sludges from treatment plants with little industrial input? To plants with significant industrial input?

JF. Metals concentrations in biosolids from treatment plants (with or without significant industrial input) will be higher than the concentrations of metals in soils, just as such concentrations are often higher in chemical fertilizers. It is comparing "apples to oranges" to compare the soils' concentration to the concentration in biosolids to be applied at a low (agronomic) rate to soils. The risk assessment developed by the leading agricultural research scientists in the U.S. evaluated metals concentrations in biosolids in terms of their effect on ultimate soil concentrations as well as the potential for plant uptake and other potential environmental impacts. Thus, appropriate comparison is the concentration of metals in biosolids with the numerical standards contained in 503; this determines whether biosolids are of sufficiently low metal concentration to be applied to agricultural soils.

JHP. Background or 'natural' total soil metal levels are roughly 0.1 to 0.01 of levels in sludge, on a dry wt. basis. There are exceptions when unusual but natural geologic conditions produce soil levels approaching those of domestic sludge for individual metals. Even in domestic sludge without significant industrial contributions copper, zinc and lead are usually elevated compared to soils. Industrial inputs usually increase all metal content values for sludge.

EZH. Specific industries may contribute relatively high levels of some particular metal or other contaminants depending on their industrial processes and effluents, however pretreatment programs are directed towards reducing such industrial inputs. Sewage from residential areas also contains elevated levels of some metals (household piping is a significant contributor of copper and lead for example). Since the concentration of metals in sludges is well above those of background soil, addition of sludges will increase the concentration of those metals. The debate is whether or not that increase represents an acceptable risk.



GNL/WMS. The following table shows the average metals concentrations in the biosolids from the eight NYC DEP dewatering facilities. Four of the eight facilities dewater a mixture of liquid sludges. The table shows the plants that typically contribute to each facility along with the estimated percent industrial flow to each wastewater treatment plant.


Dewatering Facility Contributing WPCP Design Flow MGD % Ind. Flow

Metals Concentrations, mg/Kg (dry) As Cd Cr Cu Pb Hg Mo Ni Se Zn BoweryBay Bowery Bay 150 0.92% 3.9 7.1 122 890 227 3.4 10.1 76 4.3 1,039 HuntsPoint Hunts Point 200 0.10% 4.6 13.1 197 1,168 355 4.0 20.3 65 3.8 1,366 Newtown Creek 310 0.54% Jamaica Jamaica 100 0.49% 3.7 7.0 88 1,047 203 3.1 10.2 29 5.5 1,318 Oakwood Bch Oakwood Bch 40 <0.01% 5.0 4.0 50 760 146 3.2 9.6 64 4.7 814 Port Richmond 60 0.78% Red Hook Red Hook 60 0.02% 10.0 8.8 119 915 360 4.6 14.4 51 3.6 1,180 Tallman Island Tallman Island 80 0.22% 4.4 6.9 135 969 214 3.6 8.7 54 4.6 1,163 26th Ward 26th Ward 85 0.24% 4.6 5.4 115 899 291 3.3 8.2 38 4.9 1,055 Owls Head 160 0.06% Coney Island 110 0.02% Rockaway 45 <0.01% WardsIsland Wards Island 250 0.13% 4.2 6.3 119 1,127 319 4.0 15.3 41 4.9 1,108 North River 170 0.50%

 

4. How has sludge quality changed with the implementation of industrial pretreatment programs?

JF. Industrial pretreatment programs have resulted in significantly improved quality (i.e., lower metals concentrations) during the last two decades. Comparison of the concentration of biosolids quality in the "40 City Study" conducted in 1980 with the National Sewage Sludge Survey (NSSS) a decade later (which analyzed samples from 180 POTWs for more than 400 pollutants) demonstrated reductions in pollutants of as much as 60% (lead) and 90% (cadmium) during that time. (Reference: 40 CFR Vol. 55, No. 218, Friday, November 9, 1990, pages 47238 & 47239)

While it is clear that pretreatment programs have resulted in lower pollutant levels in biosolids, it is still important to verify the actual concentration in any given biosolids source before applying them to land.

EZH. Pretreatment which involves getting industries to treat effluents before they are discharged into the sewer system has resulted in significant reductions in metals in sludges. From an environmental perspective, even more desirable than pretreatment, which is still "end of pipe" thinking, would be pollution prevention. Here the concept is to eliminate to the maximum extent feasible the use of the toxic materials in the first place. Pretreatment generally removes the contaminant of concern from the effluent, leaving a residue which must be disposed. Through changes in processes or materials used, pollution prevention can eliminate this problem.

GNL/WMS. The NYC DEP implemented its Industrial Pretreatment Program (IPP) in January 1987. Since the inception of the IPP, metals concentrations in biosolids have significantly decreased. The following table is an example of the decline in the annual average metals concentrations in digested liquid sludge for the Bowery Bay WPCP from 1984-1994.

Year

Metals Concentrations, mg/Kg (dry)

Cadmium

Chromium

Copper

Lead

Mercury

Nickel

Zinc

1984

30.8

1,934

2,437

512

2.2

200

4,521

1985

29.8

1,765

1,988

462

3.7

175

4,487

1986

29.3

1,884

1,998

444

3.2

174

4,267

1987

30.6

740

2,023

679

9.8

146

3,603

1988

25.7

461

1,485

426

3.6

95

2,576

1989

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23.2

278

1,146

304

4.1

92

1,750

1990

23.0

175

1,198

349

3.9

63

1,640

1991

19.1

153

1,234

329

6.7

65

1,629

1992

18.3

179

930

325

2.0

65

1,644

1993

11.5

251

818

287

3.8

133

1,347

1994

5.1

132

770

229

4.5

73

1,015
MANAGEMENT ISSUES
Water
5. Cow manure often finds its way to surface water, what about sludge?

JF. Unlike animal manures, the application of biosolids is governed by management practices specifically designed to prevent runoff; these include slope restrictions, setback distances, requirements for surface vegetation or incorporation of the material and timing of operations. A study conducted to evaluate the runoff water quality from pasture where biosolids and several different sources of animal manure were surface-applied clearly demonstrated that for a number of components (e.g., nitrogen, suspended solids, total phosphorus) the biosolids exhibited the least overall potential for surface water contamination; in fact, the runoff water from biosolids was very similar to the analysis of the control (no treatment) samples. (Reference: "Pasture Runoff Water Quality from Application of Inorganic and Organic Nitrogen Sources", Journal of Environmental Quality, Vol. 13, no. 1, 1984)

JHP. Under the same conditions of application and landscape, sludge would act a lot like cow manure. If not incorporated after application to sloping ground with little plant cover, potential exists for either to contaminate runoff water.

EZH. Good management is a key to preventing pollution, for either sludge or manure. Incorporation into soil, setbacks from watercourses, avoidance of steep slopes are all management actions which can help to keep these from reaching surface water. Regulations in NYS address some management issues when Class B sludges are applied.

6. Would application to frequently irrigated crops (like pecan orchards) near water courses be "safe?"

JF. Yes. The regulated application of biosolids is far less likely to result in migration of nutrients to either surface or groundwater than other agricultural materials frequently used, such as animal manures or soluble commercial fertilizers.

JHP. Application to frequently irrigated land should be safe as long as 1) sludge rate is based on nutrient (N) requirements of the crop, 2) sludge is incorporated at time of application, and 3) there is not a great deal of runoff from rains or irrigation.

7. Shouldn't the setback distance from water courses be dependent on slope, ground cover, etc. rather than recommending a set 200 ft. as in "Land Owner Guidelines?"

JF. Setback distances are only one of a number of factors required for the application of Class B biosolids. Slope, ground cover and other factors are also addressed through site specific requirements. Uniform buffers or setbacks, such as the 200 feet, while arbitrary, provide an administrative mechanism for ensuring that the most conservative standards are met with respect to the setback requirements. Some states do consider slope, ground cover and method of application relative to the setback distance required to water courses.

EZH. Ideally yes, specific site conditions would be taken into consideration. The practical realities make setting of a standard limit more feasible.

Incorporation
8. Do sludges need incorporating into soil on: croplands? grasslands? bare land? pasture? Why/why not? How?

JF. The need to incorporate into soil depends on several factors--including the isolation of the site, odor potential of the biosolids and runoff potential of the site itself. In general, incorporation is appropriate on land which is normally tilled for crop production but not on permanent hay or pasture which would be destroyed by the tillage operation. Incorporation is usually accomplished by discing the material into the top few inches (using standard agricultural equipment).

JHP. Yes, sludges should always be incorporated into soil if at all possible to avoid odor complaints, potential insect, disease, and varmint problems, and surface water runoff contamination. If it is necessary to surface apply with no incorporation, avoid runoff situations, grazing or harvesting of directly treated vegetation, and still incorporate as soon as possible.

Application Rates
9. How are application rates determined?

JF. Application rates for biosolids are generally determined by the nitrogen need for the crop to be grown (agronomic rate). An agronomic application may be made for each crop in a year, on an annual basis or less frequently, depending upon the management plan for a particular project.

JHP. Application is normally calculated on the basis of the annual N requirements of the crop grown which can be obtained from the sludge. This is usually the so-called mineralizable N, based on sludge N content and other analytical characteristics of the sludge and soil.

GNL/WMS. Application rates are determined in one of two ways. Typically, for biosolids that fail to meet the Class A requirements and/or the Table 3 limits (§503.13), the most limiting factor in determining the application rate is the agronomic rate. The agronomic rate refers to the whole sludge application rate that supplies the nitrogen requirement of the food crop, feed crop, fiber crop or vegetation grown on the land. For biosolids that only fail the Table 3 limits, the second method of calculating the application rate is through the annual pollutant loading rates (APLR) (§503.13, Table 4). Using the measured concentrations of the nine regulated pollutants, the application rate is determined by the pollutant with the lowest annual whole sludge application rate (AWSAR). The AWSAR for each pollutant is calculated from the following equation:

AWSAR = APLR
0.001C
where,

C = concentration of the metal in mg/Kg (dry weight)

APLR = annual pollutant loading rate from Table 4 of the US EPA regulations

AWSAR = annual whole sludge application rate

Therefore, the actual sludge application rate utilized by the landspreader is the lower of the rates calculated from the two methods described above.

10. What information about nutrient content would users have? Is providing such information required by regulation? If not, how would they get the information?

JF. Providing information about nutrient content is accomplished differently depending upon whether the material is applied under a state-issued permit (this applies to Class B sludges in NYS) or is the product of an approved process which can be marketed with appropriate labeling information (Class A "exceptional quality"). For land application on permitted sites, farmers typically receive information on the primary and micronutrients applied to each field based on the biosolids analysis and the tonnages of material applied. This information is also typically part of the reporting requirement for land application sites and is therefore public information. For biosolids products where individual site permits are not required, recommendations for use would generally be part of a labeling requirement, and this information would be provided to buyers/users of the product. In addition, if a product is registered as a fertilizer material, it is subject to the labeling requirements of the Agriculture Department in each state.

GNL/WMS. Information regarding the quality of the biosolids products is typically supplied in the form of a label on the bag of the material. The following is an example of the type of information supplied on a bag of New York City pellets that is marketed in Texas:

1. Total nitrogen
a. water soluble organic nitrogen

b. water insoluble nitrogen

2. Available phosphate
3. Soluble potash
4. Calcium
5. Magnesium
6. Sulfur
7. Chlorine
8. Copper
9. Iron
10. Manganese
11. Molybdenum
12. Zinc

The label also states that the nutrients were derived from municipal biosolids.

The US EPA Part 503 regulations do not require a label or information sheet for biosolids or biosolids products sold or given away in a bag or container, if the biosolids or biosolids products meet the EQ standards (see Q18). The Regional EPA administrator or the Director of a State with an approved sludge management program, however, may enforce this requirement on a case-by-case basis. If an administrator requires a label or information sheet, then the information to be supplied is as follows:

1. Name and address of the person preparing the biosolids.
2. Statement that the application of the biosolids is prohibited except in accordance with the instructions on the label or instruction sheet.
3. The annual whole sludge application rate for the biosolids does not cause any of the annual pollutant loading rates in §503.13, Table 4.

Furthermore, the person who prepares the biosolids must provide written notification to the person who applies the biosolids of the total nitrogen concentration (dry weight basis) in the biosolids.
The NYS DEC Part 360 regulations require bagged compost to have a label that states the type of waste the compost was derived from, any restriction on the use of the product, and recommended safe uses and application rates. Regulations regarding the information contained on labels will vary from state to state.


11. How and by whom are soil conditions, crop needs, precipitation etc. considered in determining application rates?

EZH. When site specific permits are required (Class B applications in NYS for example), a calculation of agronomic application rates, based on the N needs of the crop and the N contribution of the sludge is done as part of the permit application. Testing of the soil is not part of the process. For sludge products like pelletized sludges or composts, there is no required mechanism for determining appropriate rates. The same is true for fertilizers. The application of P from sludges is not considered in either scenario.

12. For a lime/sludge product, are application rates determined by nutrient or lime content?

JF. The amount of lime compared to the amount of biosolids in such a product will determine the application rate for that product. In general, Class B biosolids treated with lime will be limited by nutrients (nitrogen) since the lime content is much lower than that contained in a Class A alkaline treated product. In the latter case, the material would generally be used as a liming agent and the organic matter/nutrients from the biosolids would be incidental in terms of the application rate.

JHP. For an alkanized lime product like N-Viro, application rate is based on the agricultural soil lime requirement. Nutrients added should be subtracted from the chemical fertilizer total applied.

REGULATIONS
13. How do NYS existing and proposed regulations compare to 503 regulations? How are they more restrictive?

GNL/WMS. The following table compares the US EPA Part 503 limits to the proposed and existing NYS DEC Part 360 limits.\

Regulation

Pollutants  

 As

 Cd

 Cr

 Cu

 Pb

 Hg

 Mo

 Ni

 Se

 Zn NYS DEC Part 360 Proposed

41

10

1,200

1,500

300

17

54

290

28

2,800 Class I Compost

10

1,000

1,000

250

10

200

2,500 Biosolids Land Application
/Class II Compost

25

1,000

1,000

1,000

10

200

2,500 US EPA Part 503 Table 1 (Ceiling)

75

85

4,300

840

57

75

420

100

7,500 Table 3 ("EQ")

41

39

1,500

300

17

420

100

2,800

Testing
14. Do NYS and/or 503 regulations require measurement of background soil metals? nutrients?

JHP. No, not for either metals or nutrients.

EZH. No. Initial soils testing would be a very good idea since there is a possibility that background levels could already be high either due to natural conditions (for example the parent material from which the soil is derived) or due to other additions (which could be from purposeful additions such as some pesticides or from airborne contaminants).

GNL/WMS. The existing NYS DEC Part 360 regulations require the following analyses of the background soil as a part of the permit application (§360-4.3 (i)) for the site: 1) available nitrogen; 2) available phosphorous; 3) available potassium; 4) pH; 5) cadmium; 6) copper; 7) total chromium; 8) mercury; 9) nickel; 10) lead; and 11) zinc. The number of soil samples and analyses depends on the soil. For soils containing only one agricultural soil group (homogeneous), a minimum of one soil analysis per 50 acres is required. For soils containing more than one agricultural soil group (heterogeneous), a minimum of one soil analysis per 25 acres is required. The depth of the soil samples must be consistent with the plow layer and the depth of the applied sludge. The soil sampling and analysis is an initial requirement for the permit application, not a continuous monitoring requirement.

The US EPA Part 503 regulations do not specifically require testing of the background soils. The regulations, however, do require that the sludge is applied at or below the agronomic rate of the crop or grass to be grown. To insure that the agronomic rate of the crop is not exceeded, the land applier must first determine the available nitrogen in the soil; therefore, analysis of the soil for nitrogen is indirectly required.

15. Do NYS and/or 503 regulations require testing of sludges for nutrient content? If so, how are vendors and applicators made aware of this information?

GNL/WMS. The NYS DEC Part 360 regulations require the following analyses of the sludge on a monthly basis (> 5 MGD plants): 1) total Kjeldahl nitrogen; 2) total phosphorous; 3) total potassium; 4) pH; 5) total solids; 6) total volatile solids. The US EPA Part 503 regulations require the person who prepares the biosolids to provide written notification to the person who applies the biosolids of the total nitrogen concentration (dry weight basis) in the biosolids. Although it is not required, sludge generators or persons who prepare the sludge typically supply the land applier with information regarding the N-P-K (nitrogen-phophorous-potassium) of the material. Additional nutrient information may also be provided (see Question 10) or can be obtained by contacting the generator or preparer of the sludge.

Imported sludges and other products:
16. Is there regulation of sludges and sludge products imported into NYS? If so, how are they regulated and tested?

Crop restrictions:
17. What are the restrictions under 503 and in NYS in the use of Class A sludge products? Class B? Can they be used on crops for human consumption?

JHP. There are no official, legal restrictions on the use of 'Class A' sludge by 503. In NYS the current 360's require a waiting period of 18 months after application before any crop directly-consumed by humans can be planted (proposed revisions in NYS 38 months). In addition, sludge metal content and soil metal cumulative standards have to be met for both 'Class A and B.'

EZH. The philosophy of 503 is that sludge products meeting concentration limits for the 10 regulated metals and Class A pathogen reduction requirements can be used and distributed without further concern or regulation. There are thus no restrictions on their use. In NYS the regulations currently in place do not allow application of sludge products on crops for direct human consumption without a variance. It seems likely that when revisions are proposed to NYS regs in the fall, they will be more like the 503s. For Class B and for sludges which do not meet the contaminant levels for the metals (but are below a high ceiling limit), restrictions are placed, including the use of cumulative load limits (though how that is to be enforced is not clear). For Class B there are waiting periods before people or animals may enter the site or crops may be harvested.

GNL/WMS. Unless the Regional US EPA administrator or State Director states otherwise, biosolids that meet the "exceptional quality" (EQ) standards are not subject to the general requirements or the management practices of the Part 503 regulations. If the sludge is classified as Class B, it cannot be applied to lawns or home gardens or sold or given away in a bag or other container. In addition, there are certain site restrictions for land application of Class B sludges:

1. food crops with harvested parts that touch the sludge/soil mixture and are totally above the land surface shall not be harvested for 14 months after the sludge application,
2. food crops with harvested parts below the land surface shall not be harvested for 20 months after the sludge application when the sludge remains on the land surface for four months or longer prior to incorporation into the soil.
3. food crops with harvested parts below the land surface shall not be harvested for 38 months after the sludge application when the sludge remains on the land surface for less than four months prior to incorporation into the soil.
4. food crops, feed crops, and fiber crops shall not be harvested for 30 days after the sludge application.
5. animals shall not graze on the land for 30 days after the sludge application.
6. turf grown on land where sludge is applied shall not be harvested for one year after application of the sludge when the harvested turf is placed on lawns or land with a high potential for public exposure.
7. public access to land with a high potential for public exposure shall be restricted to one year after the sludge application.
8. public access to land with a low potential for public exposure shall be restricted to 30 days after the sludge application.

The Part 360 regulations require biosolids for land application to meet the land application limits as noted in Question 13 and one of six stabilization methods (i.e., New York City meets the stabilization requirements through anaerobic digestion). In addition to these criteria, there are other site restrictions:

1. No crop for direct human consumption may be grown on biosolids amended soil for at least 18 months after the last application.
2. Public access to the land application facility is prohibited for at least 12 months after the last application of biosolids and must be controlled during that period by the use of fences and gates, signs or posted signs.
3. Dairy cattle must not graze for at least 12 months after the last application and grazing by other animals, excluding wild game, must not graze for at least one month after the last application.

For Class I compost, the Part 360 regulations do not allow compost to be used on crops grown for direct human consumption. Class I compost can be distributed to the public, used on food chain crops, or used for horticultural applications. Class II compost is restricted to use on nonfood chain crops.


Classifications of sludges and products:
18. Where in 503 does it refer to EQ ("Exceptional Quality" designation under 503 regs)?

JF. The term "EQ" has been coined since the promulgation of the 503 regulations to provide a "shorthand" method of referring to a material which meets the pollutant concentrations contained in §503.13(b)(3), the Class A pathogen reduction requirements in §503.32(a) and one of the vector attraction reduction requirements in §503.33(b)(1) - (b)(8). Such material, because of its low pollutant concentration and treatment to reduce pathogens to below detectable levels and reduce vector attraction, can be sold to the public without the restrictions required for land application of biosolids, which relies on a combination of environmental factors and management practices to prevent excessive metal additions, reduce pathogens to negligible levels and/or reduce vector attraction.

GNL/WMS. The term "exceptional quality" is not defined or found in the US EPA Part 503 regulations. It is term that has originated over time to refer to biosolids or biosolids products that meet the following criteria:

1. pollutant concentration limits in §503.13(b)(3)).
2. one of the Class A pathogen reduction alternatives in §503.32(a).
3. one of the vector attraction reduction alternatives in §503.33(b)(1)-(b)(8).

"Exceptional quality" biosolids and biosolids products are not subject to the general requirements or the management practices of the Part 503 regulations.

19. Is there a Class B EQ (Exceptional Quality designation under 503 regs) category?

JF. No such designation is commonly used. However, biosolids which are not treated to Class A pathogen reduction levels but meet the pollutant concentration limits of §503.13(b)(3) are not subject to the requirement to track cumulative metal loading limits.

GNL/WMS. As noted above, biosolids must meet one of the Class A pathogen reduction requirements to be considered "exceptional quality"; therefore, a Class B, EQ category does not exist.

20. Do NYS and/or 503 regulations distinguish between sludges from treatment plants that do not handle significant amounts of industrial wastewater and those that do? If so, what are the differences?

JF. Both NYS and 503 regulations are based on the concentrations of pollutants in the biosolids generated from POTWs regardless of the relative contributions of industry to that treatment plant. This is a "bottom line" approach which is supported by the numerical technical standards of the regulations.

EZH. The source of the sludge is not considered in the regulations. Since residential sewage can contribute significant metals (mainly from piping), testing and concentration limits for metals are needed for sludges derived from plants serving residential areas as well as for plants with industrial inputs. There are some differences in the frequency of testing required from plants of different sizes.

GNL/WMS. The NYS Part 360's and the US EPA Part 503's do not distinguish between sludges from treatment plants which have varying amounts of industrial wastewater in the influent. The source of the biosolids is considered only to determine if the biosolids are regulated under the Part 503 regulations. Sewage sludge, as defined by the regulations, is generated during the treatment of domestic sewage in a treatment plant. Domestic sewage must be present in the influent to the treatment plant, either with itself or with other wastewater (e.g., industrial wastewater), for the removed solids to be considered sewage sludge and to be subject to regulation under Part 503. For sludge generated at industrial facilities, the guidelines are as follows:

1. If the sewage sludge was generated at an industrial facility during the treatment of domestic sewage only, then the sludge is regulated under the Part 503's.
2. If the sewage sludge was generated at an industrial facility during the treatment of industrial wastewater combined with domestic sewage, then the sludge is not regulated under the Part 503's.
3. If the sewage sludge was generated at an industrial facility during the treatment of industrial wastewater only, then the sludge is not regulated under the Part 503's.

Permits:
21. Are land application permits site specific? If a facility has a land application permit and wishes to change the location of application, what is required?

JF. In most states, for all biosolids other than those meeting the requirements of §503.13(b)(3), Class A pathogen reduction and vector attraction reduction and meeting concentration limits for metals, a site specific land application permit is required. Any new location is a separate site and would have to meet the same requirements and go through the same permitting process required for all such sites.

Enforcement:
22. What means are there to ensure that sludge is applied at an appropriate rate?

EZH. There are really no means of ensuring this. For Class A sludge products where no site permit is required, excessive application may be a concern, particularly for home use of sludge composts. More generally, even where a rate is specified in a permit (use of Class B for example) enforcement of regulations is always a concern. This is not just relevant to sludge application, but to many environmental (and other) requirements. Education to make users aware of what an appropriate rate of application is and why over application is not a good idea would be a useful means of seeking compliance.

GNL/WMS. New York City routinely inspects the transfer stations, bagging facilities and land application sites to insure that all contractors are following proper management practices. New York City receives a monthly report from both land application contractors. Merco Joint Venture directly land applies biosolids to grasslands in Texas. Their monthly report details the amount of biosolids received, the quality of the biosolids, and the acreage and plots on which the biosolids were applied. These numbers are checked for consistency. NYOFCO, which thermally dries the biosolids into pellets, includes information in their monthly report on the amount of incoming sludge, the amount of pellets to each state and vendor, maintenance and facility modifications, and community involvement. In addition, NYOFCO sends a copy of all analyses performed on the pellets to the NYC DEP.

23. Does NYS or any other state require the licensing or training of applicators?

EZH. No, not for sludge application in NYS. I am not sure about whether any states require it.

24. How are regulations enforced? How are permit requirements monitored?

EZH. In general any monitoring required under a permit is done by the permit holder (or by someone they hire to do it for them). Samples would be taken by the permittee and sent to a lab for analysis. Any lab tests would generally have to be performed by a state certified lab and sampling protocols might be specified by the environmental agency. Test results are then generally required to be submitted to permitting agency (DEC in NYS) and records also kept by the permittee. The DEC records are open to the public. This same general approach of self monitoring and reporting is applied in most of environmental regulatory programs. DEC would be allowed to do their own inspections and testing, but obviously there are staff and funding limitations. The whole question of enforcement and monitoring/verification is one that concerns many people, particularly as state budgets and staffing are reduced. One provision which communities may try and work out with people applying for permits is to develop a capacity for community involvement in monitoring (perhaps through a local health department).

GNL/WMS. The NYC DEP is required to submit an annual report for each Water Pollution Control Plant (WPCP) to the US EPA detailing all monitoring requirements as set forth in the US EPA Part 503's. In these reports, the NYC DEP supplies information regarding the amount of biosolids produced from each treatment plant, the biosolids distribution to each contractor, the metals quality of the biosolids, and the parameters needed to meet the pathogen reduction and vector attraction reduction requirements. The US EPA conducts surprise inspections of the City's facilities and records to insure compliance with all federal regulations.


Revisions to NYS Regs
25. When are proposed revisions to NYS par 360 regulations going to be available for public comments?

26. Is NYS considering adopting the 503 regulations? If not, what differences?

27. Is NYS using a risk-based approach to revising the 360 regulations?

28. How does DEC assess health and toxicological impacts in establishing regs? How is DOH involved in the process?

29. Will NYS issue generic BUDs ("beneficial use determination") for sludges and sludge products for use on food crops? What is the significance of such a designation?

Other:
30. Chromium was removed from 503 regulations. Should it be monitored? regulated?

JF. Chromium was removed from the 503 regulations because no data existed to support a limit since no negative effect has been documented in the literature from biosolids-applied chromium in field studies.

JHP. Probably should be monitored and continued regulated for the time being, although level continues to drop in sludge and toxic impact seems minimal.

GNL/WMS. New York City and its contractors continue to monitor biosolids and pellets for chromium. Although chromium was removed from the Part 503 regulations, it is still included in many State regulations.

31. Molybdenum was removed from 503 regulations. Should it be regulated? Are regional limits a possibility?

JF. Molybdenum was not removed from the 503 regulations; there is still a ceiling limit (a concentration above which biosolids may not be applied to land) and the cumulative and pollutant concentration limits for Mo are being re-evaluated in light of additional data with the intent that new limits will be imposed. It should be noted that the issue of molybdenosis is one that is a regional concern--occurring only on alkaline soils in western United States. It therefore appears that regional limits might be a possibility in the case of molybdenum.

JHP. Molybdenum should be monitored and regulated because of animal health issues relating to ingestion when animals graze on lands or consume crops to which sludges have been applied and where there are sludge residues. Regional or State limits could be imposed.

METALS IN SOILS
32. Since some metals are considered necessary micronutrients (ie. Cu, Zn) and others are not (like Hg, Pb), why are they jointly considered "heavy metals" and subject to regulation?

JHP. The so-called heavy metals are considered together in regulation because all are toxic to animals (humans) and/or plants at some level in the soil, even if they may be required at lower levels for proper nutrition. The trick is to apply adequate or safe levels without over applying and reaching toxic levels.

EZH. As the question points out, the terminology is confusing. There are indeed desirable levels of some micronutrient metals and other metals for which there are no positive benefits and thus we would hope to eliminate them to the extent possible. For all of them, however, there are negative impacts (toxicity to plants or animals) at some concentrations which is why maximum concentration limits are set.

33. Do heavy metals accumulate in soils?

JHP. Yes, the regulated 'heavy' metals accumulate in soil. If managed correctly, they remain quite near the application site also, so that water and non-target organisms aren't adversely affected.

EZH. Additions to soil can follow several potential paths. They can remain in place and thus accumulate as more are added, they can move out with ground or surface waters, they can volatilize (evaporate), they can be taken up by plants and end up wherever the plant materials ends up (harvested perhaps), or they can be transformed (and those transformation products then follow one of these paths). The pathway that is followed depends on the physical, chemical and biological properties of the material being added. Most materials will predominantly, but not exclusively, follow one path depending on the site conditions. So for example, most metals are relatively insoluble, non-volatile and are not readily taken up by plants (cadmium being a notable exception). They would thus tend to accumulate where applied. However, soil pH impacts the solubility of many metals (and thus how much leaches to groundwater).

34. How do metal concentrations in sludge (as ppm) relate to the cumulative load which accumulates in the soil?

JF. Metal concentrations in biosolids can be converted to pounds per dry ton by multiplying ppm (dry weight) of the metal by 0.002. Based on the tonnages applied to the soil, a cumulative load (in pounds) can then be calculated. To relate this amount to ppm in the soil, divide by two since there are two million pounds of soil in a plow layer (approximately six inches) where the metals from biosolids accumulate. For example; if cadmium is 6 ppm (dry weight in biosolids which are applied at 5 dry tons/acre:

6 x 0.002 x 5 = 0.06 lbs Cd/acre added
0.006 = 0.03 ppm Cd added to plow layer
2

JHP. Most sludges contain metals at levels much below the quality limits. If metal levels approach quality limits in a particular sludge, the 503 cumulative limits will be reached after about 100 applications.

35. Is background soil metal content a concern?

JF. Background soil metals are generally not of concern unless there is reason to believe that a site has been contaminated by a previous industrial or chemical addition to that soil. The cumulative soil concentrations which form the basis for the "no adverse effect levels" of 503 assume a background soil metal concentrations within the ranges normally encountered. The basis for allowing accumulation of biosolids-applied metals when the metals concentrations in biosolids are low (i.e., meet pollutant concentration limits) is based on the presence of many other metals in biosolids which provide "binding capacity" for those metals of concern. For example, iron and aluminum, which are naturally present in significant concentrations in native soils and occur in biosolids, provide a means of reducing bioavailability of metals added to soils through biosolids additions.

JHP. Background soil metal content should be figured into the cumulative limit.

EZH. Initial testing of background soils is not required before sludge applications, but would be a very good idea. Background soil metal levels can vary widely depending on both natural conditions (the geology of the parent material is key) and on contaminants which may be present. The regulations are based on "normal" soils, but since an individual site may be far from the average, testing should be done prior to application.

36. What is meant by "bioavailability" versus the simple measured concentration of a contaminant?

JF. As discussed in the answer to the previous question, bioavailability refers to the amount of a particular metal or other pollutant which can be biologically assimilated by a living creature (human, animal, crop) through a series of environmental pathways. Amounts of bioavailable metals, for example, differ from the total amounts in either soil or a material applied to the soil. Metallic binding sites (aluminum and iron) combined with low concentrations helps the metals of concern in biosolids have low bioavailability and, therefore, prevents risk to the crops, animals or humans potentially affected through the various environmental pathways. Research has also clearly demonstrated that the bioavailability of metals in biosolids is significantly lower than that of metal salts (the chemical forms).

JHP. Nutrients and metals exist in several chemical forms in sludges and soils. Some of these forms are more soluble than others, and so are more bioavailable. For instance, there's always quite a bit of P in soil, but because it's so insoluble, little becomes bioavailable to plants or microorganisms during one season.

EZH. Bioavailability refers to the amount of some contaminant (or nutrient) which is accessible to plants or animals. Most lab tests (and the regulations) are based on the total concentration of the particular contaminant which is present. Not all of that is available to organisms (you might think of it as not being bioactive - it might be ingested and pass right through the animal). Bioavailability of a particular contaminant depends on many chemical and physical factors. One issue under debate by sludge/soil scientists is how bioavailability may change as conditions change over time. For example binding of some contaminants to the organic matter in sludges helps to reduce bioavailability. If sludge ceased to be applied and the organic matter decays away as it is digested by soil organisms, will that cause an increase in bioavailability? Long term experiments are needed to answer such questions.

GNL/WMS. Bioavailability, as defined by Webster's Dictionary, refers to "the rate at which a drug, trace element, etc. enters the bloodstream and is circulated to specific organs or tissues". Thus, bioavailability is expressed in mass of substance per unit time, whereas a measured concentration is typically expressed in mass of the substance per unit mass of matrix (i.e., sludge, compost, pellets, etc.). Therefore, the two measurements cannot be equated. The bioavailability of a substance may or may not be dependent on the measured concentration; research has to be performed to ascertain the relationship between the two. In addition, other constituents in the matrix may influence, either more or less, the bioavailability of a particular compound.

SLUDGES VS. OTHER SOIL AMENDMENTS
37. Are there metals in fertilizers? Are they subject to regulation in NYS? The U.S.? Europe?

JF. Because many fertilizer are mined from the earth, they may contain significant amounts of trace elements (metals). Typically, in NYS and the U.S., these materials are not subject to regulations with respect to metal content. In some European countries they are so regulated.

JHP. Yes, there are metals in fertilizer, and not regulated unless plant micro-nutrient claims are made, in which case minimum levels are required and maximum levels are not set.

GNL/WMS. The following table shows the metals concentrations in a typical 19-19-19 fertilizer. The analysis was performed by a laboratory at the Ohio Agricultural Research and Development Center.

Metal

Concentration (mg/Kg)

Arsenic

2.1

Cadmium

0.9

Chromium

28.9

Copper

2.3

Lead

< 2.0

Mercury

< 1.0

Molybdenum

6.3

Nickel

4.9

Zinc

23.9
New York State requires commercial fertilizers to meet a guaranteed analysis (see Q46) for plant nutrients. Metals in fertilizers are not regulated, but warning labels are required if certain concentrations are exceeded (see Q46).


38. If not regulated, do metals in fertilizers represent more of a risk than sludges which are regulated?

JF. The risk associated with fertilizers depends upon the concentration in the fertilizer, the application rates applied and the number of applications to a particular site. Because chemical fertilizers are typically applied at a much lower rate than are biosolids, it requires a significantly higher concentration of metals to apply the same amount from a single fertilizer application. However, these metal-containing fertilizers may not demonstrate the same binding capabilities as do biosolids (they may be more bioavailable). In any case, only a mathematical calculation of cumulative loading will provide perspective on a particular metal-containing fertilizer.

JHP. In general, metals in chemical fertilizers do not pose more of a risk than in sludge. The amount and fate in the soil of metals is what's important, not so much how it gets there. If similar additions of metals were made to soil in the form of sludge and separately in chemical fertilizer, fertilizer metals would be relatively more available for a short time. In reality in such a scenario, other problems with the salt and/or nitrate added in chemical fertilizers would be a more serious risk.

39. Is the long-term use of metal-containing fertilizers a significant risk?

JF. As noted in the answer to the previous question, such risk depends upon concentration, amounts used and length of time used.

JHP. After a very long-term use of certain fertilizers, mostly the phosphate chemical fertilizers, metals may become a significant risk.

40. Does NYS require the registration of sludges as a soil amendment or fertilizer? What about other states?

JF. Most states provide for the registration of fertilizer materials based on nutrient content which must be verified to provide a guaranteed minimum. These requirements typically are administered through the State Department of Agriculture and apply only to those materials for which a minimum guaranteed nutrient analysis is given.

GNL/WMS. New York State does not require biosolids or biosolids products to be registered as a soil amendment or fertilizer. From a marketing standpoint, however, it may be advantageous for the biosolids manager to sell the product as a commercial fertilizer.


41. Why is there greater concern over application of human waste to land when animal waste and fertilizers have been applied for years?

JF. The unfamiliarity of the general public with the methods and controls imposed on wastewater treatment coupled with legitimate public health questions and a common misperception that wastewater is somehow "toxic" have led to misplaced concerns about the practice and the regulations surrounding beneficial use of biosolids. In some cases, nuisance conditions, such as odors, have not been adequately addressed and have led to opposition to facilities and projects which precludes the opportunity to develop a dialogue in which the safeguards and legitimate issues can be explored.

JHP. Mostly psychological, as biologically stabilized human waste (no industrial input) should carry no more risk with its use than animal wastes or fertilizers. The main technical concern is pathogen content and infectivity from untreated human waste. The same best management practices should be applied in all cases.

EZH. There are indeed many similarities and thus concerns should be similar. However, there are also differences. Sludges contain contaminants from industries and from residences (including metals such as copper and lead leached from pipes). The nature of sewage treatment is such that some contaminants which may be present in the waste water are concentrated in the sludges.

42. How do the impacts and benefits of land spreading septic tank wastes compare to sludge application?

JF. Septic tank pumpings are generally much less homogeneous than the solids produced by the constant recirculation which occurs in a wastewater treatment plant producing biosolids. Under 503, lime treatment of septage may be required prior to land application (although to a lesser degree than for Class B biosolids) and restrictions on growing food crops and public access are imposed. The application of septage on farmland is less likely to provide a known amount of plant available nitrogen than are biosolids. The value of septage depends upon the solids content, application rate and the nutrient content which can only be determined by appropriate analytical testing.

JHP. The impacts and benefits are very similar, being nutrient and organic matter additions, with potential risks from pathogens being a bit greater from septage (incorporation would essentially neutralize that risk) and metal buildup much greater risk with sludge.

INFORMATION AND LABELING
43. How can a citizen get information about sludge application in their community for Class B? for Class A?

EZH. Since Class B applications require a site permit, information should be available through the environmental permitting agency. For Class A sludge products, information on the product in general should be available from the environmental agency. There is, however, no predictable way to learn about whether a Class A product has been applied on any particular site since under 503 regulations if a product meets "EQ" standards, it can be distributed without restriction or tracking.

GNL/WMS. Citizens can contact their local or State government offices to find out how their community is handling their biosolids and if biosolids from out-of-state are being applied in the area. Persons who prepare biosolids for land application in a State other than the State in which the biosolids were prepared are required, by regulation, to contact the permitting authority of the State in which the biosolids are applied (see Q44).

44. What are the labeling and notice requirements for Class B? Class A?

EZH. For Class B application sites there are posting requirements which simply inform people to stay off the site for a specified time period. For Class A there are no requirements. Some people believe that labeling should be required to inform users about the source of the materials, the concentration of nutrients and contaminants, use/management guidelines and concerns about improper use.

GNL/WMS. Class A biosolids and biosolids products that are not "exceptional quality" are required to supply certain information regarding the product if it is sold or given away in a bag or container. The requirements, as per the 503 regulations, are as follows:

1. Name and address of the person preparing the biosolids.
2. Statement that the application of the biosolids is prohibited except in accordance with the instructions on the label or instruction sheet.
3. The annual whole sludge application rate for the biosolids does not cause any of the annual pollutant loading rates in §503.13, Table 4.

The person who prepares the biosolids is responsible for providing the necessary information for compliance with the general requirements (§503.12) of the Part 503 regulations. If the biosolids are applied in a State other than the State in which the biosolids where prepared, then the person who prepared the biosolids is responsible for providing a written notice to the permitting authority of the State in which the biosolids were applied. The notice includes the following information:

1. Location of each land application site (street address or longitude and latitude).
2. The approximate time period for application of the biosolids to the site.
3. The name, address, telephone number and NPDES permit number of the person who prepared the biosolids.
4. The name, address, telephone number and NPDES permit number of the person who applied the biosolids.

Unless required by an US EPA administrator or a State Director, EQ biosolids and biosolids products do not have to meet any of the above requirements.

Class B biosolids and biosolids products can not be sold or given away in a bag or container; therefore, the labeling requirements do not apply. Class B biosolids and biosolids products are, however, required to provide a written notice, as mentioned above, for out of state land application.


CONCERNS
General
45. Since sludge disposal at sea was banned, why shouldn't it be banned from land application?

JF. Land application to soil to grow plants provides a means for utilizing the nutrients contained in biosolids; no such opportunity is available when this material is disposed in the ocean with no opportunity to provide a suitable environment where its components can be effectively recycled. Since water and soil are two very different media, it makes sense that a nutrient-rich material such as biosolids would be used more effectively in the latter than in the former.

JHP. Because the ocean-dumping ban was political more than technical, I would consider both ocean and land application viable, as long as it's done correctly and with satisfactory monitoring.

EZH. The same nutrients can be a serious pollutant in water and a beneficial resource on land. The major benefit of sewage treatment has been in removing organic matter and nutrients from the sewage before it is discharged. Without this treatment, sewage discharges resulted in algae blooms and depleted the waters of oxygen needed to support aquatic animals. On land, the organic matter and nutrients, if not applied in excess, have the potential to benefit plant growth. So use on land can recycle the organic matter and nutrients.

GNL/WMS. Biosolids products sold or given away for home use have to meet the requirements for EQ biosolids as per the Part 503 regulations. As noted above, EQ biosolids and biosolids products are not required to meet any of the general requirements or management practices unless requested by an US EPA administrator or a State Director.


46. Did EPA risk assessment address only contaminants for which there was adequate data? If so, what is the significance of this exclusion of many other contaminants?

JF. The risk assessment for biosolids began in the early 1980's with several key components, such as determining the pollutants of concern, developing risk assessment methodologies, determining appropriate risk-based limits and management, and issuing comprehensive risk-based regulations (i.e., the Part 503 Rule). In 1984 EPA developed a list of approximately 200 pollutants for possible consideration based on available data for such factors as human exposure and health effects, phytotoxicity (adverse effects on plants), effects in domestic and wild animals, and frequency of occurrence in biosolids. Four panels of experts reviewed the initial 200 pollutant list and recommended approximately 50 to be studied further based on the probability of a pollutant's toxicity and the availability of toxicity and exposure data. Using a hazard profile index, these 50 pollutants were ranked to reflect their hazard attributable to biosolids (i.e., excluding background exposures). This process resulted in identifying a list of 22 pollutants to be assessed for risk from land application. A very few, mainly synthetic organic compounds, were deferred for future evaluation when more data will become available. In general, organic compounds have been found to be present in extremely low concentrations in biosolids and are not expected to be problematic with respect to land application. (Reference: A Guide to the Biosolids Risk Assessment for the EPA Part 503 Rule., U.S. EPA Office of Wastewater Management, EPA 832-B-93-005, September 1995.)

EZH. Yes, the risk assessment was restricted to contaminants for which sufficient data existed to actually try and perform an assessment. Obviously one cannot perform a risk assessment absent appropriate data. This is a major concern to some who believe that some contaminants (particularly toxic organics, including dioxins) may pose significant unregulated risks and that our ability to assess risks, particularly complex risks such as those at an ecosystem level, is not adequate to make decisions based on risk assessments. Others believe that our ability to assess risks is adequate and is the best basis for moving forward in managing sludges.

GNL/WMS. The definition and requirements for fertilizers may vary depending on the State. In New York State, a commercial fertilizer is defined as any substance containing one or more plant nutrients which is "used for its plant nutrient content, and which is designated for use or claimed to have value in promoting plant growth, except unmanipulated animal and vegetable manures, agricultural liming material, wood ashes, gypsum, and other products exempted by regulation of the Commissioner." This definition was obtained from Article 10 of New York Agriculture and Markets Law Relating to the Sale and Analysis of Commercial Fertilizer. New York State Law requires a label for all commercial fertilizers with the following information:

1. Net weight of the contents of the package.
2. Brand and grade under which it is sold.
3. Name, street, or post-office address of the principal licensee.
4. Guaranteed analysis.

Including in the guaranteed analysis are the minimum percentage for total nitrogen (N), available phosphoric acid (P), and soluble potash (K). In addition to N-P-K, commercial fertilizer in New York State must meet the following criteria as a part of the guaranteed analysis:

Element

Minimum Concentrationof Element

%

mg/Kg Calcium

1.00

10,000 Magnesium

0.50

5,000 Sulfur

1.00

10,000 Boron

0.02

200 Chlorine

0.10

1,000 Cobalt

0.0005

5 Copper

0.05

500 Iron

0.10

1,000 Manganese

0.05

500 Molybdenum

0.0005

5 Sodium

0.10

1,000 Zinc

0.05

500
If the fertilizer product contains more than 0.03% boron or 10 mg/Kg of molybdenum, then warning labels are required on the product.


47. If metals will persist "forever" in soils, why is there so little concern about them?

JF. It is precisely their persistence in soil (from which they originated) that has led to the thousands of research projects on metals' behavior in soils, crops, water systems and other environmental compartments which have been conducted during the last several decades. We know a great deal about how metals behave in soils and the means by which they are or are not available to crops, humans and animals. With respect to metals applied through biosolids applications, the leading research scientists in this area have concluded that the questions which led to much of the research conducted during the 1970's and 80's has answered the questions raised by concerned scientists. As of the promulgation of the 503 Rule in 1993, while there are some additional "loose ends" to be settled, it is now appropriate to focus on developing strategies for POTW's (publicly owned treatment works) to implement land application of biosolids. (Reference: Sewage Sludge: Land Utilization and the Environment, SSSA, Clapp et.al. eds., 1994)

JHP. There is concern for long-term metal buildup in soils by all parties. The dispute comes in establishing safe buildup, or cumulative, levels.

EZH. The essentially irreversible build up of metals is precisely why they are of concern and have been studied and regulated. The 503 standards are based on an assessment that lead EPA to conclude that sufficient data exist to calculate acceptable cumulative loads as embodied in the regulations. Not everyone agrees. Some soil scientists believe that levels for copper, zinc, cadmium and nickel should be about 10 times lower in order to protect soil health and sensitive crops. Concerns about protecting soils and ecosystems in perpetuity leads others to believe that a risk based approach to standards is inappropriate and rather to advocate for a "no net degradation" standard in which metals cannot be applied above levels in background soils.

GNL/WMS. To the best of our knowledge, no harmful effects have ever been determined as a result of ocean disposal, in particular at the 106 mile offshore site. The Ocean Dumping Ban Act, more htan anything else, was passed because of beach wash-up in 1986 and 1987. In all probability, the wash-upof debris was caused by combined sewer overflows along the East coast.

48. The National Research Council report ("Use of Reclaimed Water and Sludge in Food Crop Production") pointed out that the National Sewage Sludge Survey procedures failed to provide reliable estimates of frequencies and concentrations of contaminants and that the EPA regulations inappropriately excluded toxic organic contaminants from regulation; what are the implications of these findings? Should a general warning be issued to farmers and the public about these findings?

JF. This question reflects the difficulties encountered when a single point or comment made as part of a larger discussion is taken out of context. With respect to organic chemicals, the NRC report also states: "Available evidence indicates that most trace organic chemicals present in sludge are either not taken up or are taken up in very low amounts by crops after sludge is applied to land. The wastewater treatment process removes most of these organic chemicals and further reduction occurs when sludge is processed and after it is added to soil. Consequently only negligible quantities of toxic organic chemicals from municipal wastewater systems will persist in soils for an extended period."
The report goes on to state that the study did reveal some inconsistencies in EPA's approach to risk assessment and that to improve the overall integrity of the regulation, EPA should better address the exemption of organic pollutants. EPA opted not to regulate such chemicals if they had been banned and were no longer manufactured, or detected in less than 5% of the samples or were found in concentrations low enough not to exceed the risk-based loading rates. What the NRC report recommends as a further precautionary effort is that a better survey be conducted to verify the levels of these compounds in biosolids and that consideration be given to including those chemicals which EPA chose not to regulate if there is a likelihood that they may still be found in certain situations. In any case, there are numerical standards for a number of organic compounds which were developed for the 503 Rule (in order to allow removal credits for POTWs), and those standards provide a good means of evaluating biosolids quality with respect to organic pollutants. The NRC report did not state nor suggest that a general warning on this issue is necessary or appropriate.

JHP. Yes, I believe warnings pointing out that lack of information does not remove potential risk should be part of regulatory labeling or information programs for use of sludge (besides the things we do know about).

EZH. One of the significant shortcomings of the 503 regulations is the lack of labeling required for sludge products. Consumers should be able to easily see what they are buying, including contaminant levels as well as information about regulatory standards. I would not characterize this as a warning, but rather as consumer information which I believe should be widely available for many products to help people make informed choices.
The NRC report was generally very positive about the use of sludges on crops, but it did contain a number of recommendations including more restrictions on sludge for home use, better testing for pathogens and reevaluation of the toxic organics. The NRC report dealt almost exclusively with the issue of sludge safety in regard to food crops. It did not assess the direct ingestion pathway whereby children are exposed by eating soil (a very common occurrence). Interestingly, this pathway was the one which most of the 503 standards are based on since it resulted in the lowest concentrations considered by EPA to be an acceptable risk.

GNL/WMS. During the initial phase of the biosolids risk assessment process in the early 1980's, the US EPA identified 200 pollutants of concern. The list of pollutants was developed based on available data regarding the nature and potential risks associated with the pollutants. The following list details the areas that were examined in identifying the 200 pollutants.

1. human exposure and health effects data
2. plant uptake of pollutants
3. phytotoxicity
4. effects on domestic animals and wildlife
5. effects on water organisms
6. frequency of pollutant occurrence in biosolids

Based on a review by four panels of experts, 50 of the 200 pollutants were recommended for further study. This assessment was based on the following:

1. toxicity and exposure data on the 200 pollutants
2. probability that human and environmental exposure to the pollutant would occur via land application, surface disposal, incineration, or ocean disposal of biosolids.
3. probability that the pollutant would be toxic when exposure occurred through the use or disposal of biosolids.
4. use of best professional judgement

In developing the proposed rule for the Part 503's, the US EPA used data and information from a 1978 "40 Cities Study". This study was also used during the initial risk assessment process. The US EPA recognized that data on pollutant concentrations in biosolids required updating due to the initiation of pretreatment programs by POTWs, changes in wastewater treatment, and the establishment of new businesses which may increase industrial discharges to POTWs. Thus, the National Sewage Sludge Survey was conducted to obtain current data. This survey included analyses from 180 POTWs for 412 parameters.

51. If sludges provide significant benefits, why is a lot of NYS sludge being exported to other states?

JHP. Because the benefits don't necessarily outweigh the risks, nor fit into NE farming operations.

EZH. One reason is that sludge is produced every day and northeast weather conditions restrict application to non-winter. Another probable reason has to do with public acceptance and the density of population.

GNL/WMS. With the passage of the Ocean Dumping Ban Act in 1988, which amended the Marine Protection Research and Sanctuaries Act (MPRSA), the practice of ocean disposal of sewage sludge ended. As a result, New York City ceased their practice of ocean disposal on June 30, 1992 and began a program of beneficial use. Although the NYS DEC and the US EPA support the beneficial use of biosolids, this issue has and continues to be very controversial in New York State. Many people, especially in the field of academia, have raised concerns over the applicability and adequacy of the US EPA 503 regulations with regard to the low pH soils of New York State. Furthermore, prominent legislators introduced bills in their respective houses in the spring of 1993 that would have severely limited the land application of biosolids in New York State. In addition, many environmental groups and agricultural organizations are opposed to the use of biosolids in certain areas of New York State.

Therefore, due to the urgency in having contractors in place by July 1, 1992 and due to the staunch opposition to biosolids application in New York State, New York City chose to manage its biosolids out-of-state during its Interim program. Approximately 24% of the City's biosolids are used as a soil conditioner to improve the growth of cattle feed grasses in Texas. Another 70% of the biosolids are heat dried at a privately owned and operated pelletizing facility located in the Bronx. The pellets are marketed primarily as a fertilizer in a wide range of agricultural applications throughout the United States. Although the remainder of the biosolids could be beneficially used, the biosolids are instead taken to a landfill for contractural reasons. The Interim Program will last until June 30, 1998, at which time the Long Range Program will go into effect. It is predicted that a portion of New York City's biosolids or biosolids products will be applied in New York State during the Long Range Program.

There are, however, other municipalities that have viable and successful land application programs within New York State, whereas some municipalities opt for landfills or incineration.

Objectivity:
52. Who funded the videoconference? Why?

EZH. The videoconference was funded by the Cornell Waste Management Institute and Cornell Cooperative Extension which were responsible for its content. The funding which CWMI used for the program came from the State of NY and the College of Agriculture and Life Sciences.

53. Why should we believe the assessment of those who stand to profit or those whose job it is to manage sludges?

EZH. It is always a good idea to be mindful of the points of view which spokespersons bring to an issue. Clearly different people have different perspectives based on a number of factors, including their job responsibilities as well as their general values and framework (eg. some people are more oriented towards technology and others are more conservative and generally risk averse). Nobody has "the right answer" so we must each gather information from a variety of sources and think for ourselves.

GNL/WMS. Government officials, whether from the US EPA, NYS DEC or NYC DEP, are committed to serving the public, not vendors or contractors. To that end, the NYC DEP strives to produce the most environmentally safe biosolids management program within economic reason. Currently, New York City has budgeted hundreds of millions of dollars to manage its biosolids over 15 years starting in July 1998. True, New York City could spend many more millions on biosolids management, but the additional cost could result in higher taxes and sewer rates or reductions in other more important programs, such as education. Many of the public officials who work in the biosolids management area live in the same kind of communities as those people who have concerns; but, based on our experience and training, New York City feels that the US EPA has more than adequately addressed the risks associated with biosolids during the promulgation of the Part 503 regulations. It is understandable that the public will not totally trust its government, but people should also realize that government officials have been trained and educated to handle the problems and issues that affect the general population.

Exposure:
54. Are farm workers adequately protected under 503 regulations, especially in intensive labor crops like vegetables and fruit trees? Did the risk assessment address their exposure?

JF. The risk assessment addressed the exposure of farm workers as well as individuals living on a farm and consuming the produce and animal products from that farm. These particular pathways of exposure were not the limiting pathways for the numerical standards established in 503 (i.e., the actual 503 standards are lower than would be required to protect farm workers).

EZH. Where Class B sludge is being applied, providing information to farm workers on sludge and how to manage it to minimize risks should be required.

GNL/WMS. In their risk assessment, the US EPA examined 14 different pathways of exposure from land application of biosolids and biosolids products. Three of the 14 pathways can be related to the exposed farm worker as stated in the question:

1. Humans eating crops grown on biosolids amended soil.
2. Humans ingeting biosolids amended aoil.
3. Tractor operators exposed to dust from biosolids amended soil.

Considering the conservative approach used by the US EPA in assessing the exposure from each of the above pathways, it is apparent that the farm worker would be adequately protected under the regulations.

55. Is the risk of exposure to lead adequately addressed in the 503 regulations?

JF. Yes. The critical exposure pathway for lead is Pathway 3, a child ingesting biosolids that contain lead. Using EPA's generally accepted biokinetic model to calculate protective limits, an allowable lead concentration in biosolids of 500 ppm was derived. Because data from studies of animals whose diets consisted of up to 10 percent biosolids had demonstrated that body burdens of lead did not increase until the lead concentration of biosolids fed to the animals exceeded 300 mg/kg, EPA made a conservative policy decision to use the lower of the two sets of data--300 ppm--as the pollutant concentration limit in the final Part 503 Regulation to provide an additional margin of safety for growing children.
In addition, rat feeding studies have demonstrated that the bioavailability of biosolids-bound lead is only 5 percent, rather than the 60 percent bioavailability assumed in EPA's biokinetic model calculations. This is a 12-fold over-estimation of actual bioavailability which makes the 300 mg/kg limit even more conservative. (Reference: A Guide to the Biosolids Risk Assessment for the EPA Part 503 Rule, U.S. EPA Office of Wastewater Management, EPA 832-B-93-005, September 1995)

EZH. I believe there is a need to reevalute the lead standard as well as the other standards which were based on the risks from a child eating sludged soil. The lead standard of 300 ppm is based on a child ingesting sludge. A paper by the leading recognized expert in this field (Calabrese) published after the 503 standards were set suggests that the rates at which children eat soil is 9 times higher than the rate used in the EPA risk assessment. That would indicate that the standard for lead as well as for the other metals for which ingestion is the limiting pathway is 9 times too high. In addition, for lead in particular, the levels which are found to impair human development are continuously being revised downward, so it is not unlikely that levels suggested to be "safe" today will be found to be harmful. Lead is one contaminant for which the "lower the better" should be the guiding principle.

GNL/WMS. As noted in Q54, the US EPA examined the risks associated with each pollutant through 14 different pathways. The exposure pathway found to be the most limiting for that pollutant was used in developing the regulatory limits. For the case of lead, the US EPA also conducted an internal review to insure that the risk of exposure to lead was adequately addressed. During this review, it was argued that the Integrated Exposure Uptake Biokinetic (IEUBK) model should be implemented in determining the lead concentration limits for biosolids. This model is frequently used in calculating protective limits against lead risks. Using this model, the US EPA determined that the allowable lead concentration was 500 mg/Kg. The US EPA, however, decided to use a concentration of 300 mg/Kg based on the results of the limiting pathway for lead, which was biosolids ingested by children. Considering the conservative approach taken by the US EPA, the risk of exposure to lead was adequately addressed in the regulations.

56. Is lead taken up by plants a significant risk?

JF. No. The crop uptake pathways were not limiting for lead in the 503 risk assessment. The National Research Council report on using biosolids in food crop production found lead limits not to be applicable for food-chain exposure, and determined that the margins of safety provided by 503 for all metals ranged from 6 to over 1700 times more protective than necessary to provide food crop protection.

JHP. No, lead in plants is not a significant risk. Lead on plants can be (as dust).

57. Are heavy metals or toxic organics taken up by root crops, vegetables? If so, are they then a risk to people eating those crops?

JF. As noted in the response to the question 56, the food chain pathway is not limiting for any of the metals. The pathways which involve metal uptake are set to protect the crops themselves which would be affected at much lower levels than the levels which would impact people eating those crops. Organic compounds found in biosolids are either not absorbed or are absorbed by plant roots in such small amounts that they do not present a threat to consumers of food crops. (Reference: Use of Reclaimed Water and Sludge in Food Crop Production, National Research Council, National Academy of Sciences, National Academy Press, Washington, DC, 1996.)

JHP. Yes, metals at least are taken up by leafy vegetables and root crops. This can occur to the point of food chain risk, although the EPA risk assessment supposedly set cumulative soil levels protective of the food chain via this pathway.

EZH. For most contaminants uptake and ingestion by eating of crops is not the most "risky" route of exposure. For cadmium, however, this route may be significant. The 503 standard for cadmium is not based on this pathway of exposure, but there are many who feel that the cadmium standard is not sufficiently protective and the crop uptake/ingestion route might be more appropriate.

GNL/WMS. Biosolids are a complex material composed of many substances. Certain components (e.g., iron, organic matter, etc.) help to bind the pollutants in the biosolids, making the pollutants less available to plants, animals and humans. Therefore, the risk of bioavailability and phytotoxicity are relatively low when the biosolids are applied at an appropriate rate. The US EPA evaluated the risks associated with humans eating crops grown on biosolids amended soil for 10 metals and 12 organic pollutants. Pathways #1 and #2 were not the limiting pathway for any of the 22 pollutants; these pathways involve humans (non-gardeners (#1) and gardeners (#2)) ingesting crops grown on biosolids amended soils.

58. Is risk from exposure to fungi and molds addressed in the 503 risk assessment? If not, is this a serious omission?

JF. Since fungi and molds are not typically present in significant numbers in biosolids, the 503 regulations are based on controlling pathogenic organisms which might present a potential risk to human health. These include certain species of bacteria, viruses, protozoa and helminth worms which are the organisms of concern in this regard.

JHP. No, to both fungi and mold risk, and no to this omission being serious.

EZH. The fungi and mold issue is relevant to composting facilities, but not apparently to land application.

59. What would be the risk associated with bacteria (nocardia ssp for example) which survive the treatment process when Class B sludges are applied?

JF. The access and crop growing restrictions and other management practices required on application sites where Class B biosolids are applied are designed specifically to be equivalent to the additional processing required for Class A, which is not subject to those management practices. Therefore, any surviving organisms, either pathogens or non-pathogenic (such as nocardia), are not an issue under the condition of use for Class B biosolids.

EZH. My knowledge about pathogens is very limited, but it is my understanding that bacteria are reasonably well deactivated through land application but that survival of viruses or pathogens that encyst (such as cryptosporidium) may be a greater issue.

Evidence:
60. What data are available regarding health related problems relating to sludge application?

JF. As noted the National Academy of Sciences' National Research Council report on "Use of Reclaimed Water and Sludge in Food Crop Production" (1996), "There have been no reported outbreaks of infectious disease associated with a population's exposure--either directly or through food consumption pathways--to adequately treated and properly distributed reclaimed water or sludge applied to agricultural land." The report also notes that since there are many sources of infectious disease agents other than the use of reclaimed water or biosolids, such as prepared food and person-to-person contact, the potential added exposure to pathogens from the proper recycling of these materials is "minuscule compared to our everyday exposure to pathogens from other sources."

EZH. This is very controversial. In part, epidemiologic evidence is very difficult to compile so that actually associating health problems with sludge application (or other environmental exposure) is extremely difficult to document. There are "anti-sludge activists" who believe that a number of health problems are associated with sites of application, while many sludge application proponents believe that there are other causes or no real documented problems.

61. Are there epidemiological health studies on neighbors residing adjacent to or near farms using biosolids?

JF. An epidemiologic study on human exposure to pathogens in biosolids compared health effects in 164 people from 47 farms receiving agronomic biosolids applications to 130 people from 45 farms constituting the control (no biosolids applied) group. Participants answered monthly surveys, had annual tuberculin testing and serologic testing of quarterly blood samples. The study determined that there were no significant differences in the health of those living on farms where biosolids was applied compared to the control group. Similarly, since the monthly surveys included questions about farm animals' health, no differences were reported for domestic animals from biosolids-applied versus control farms. (Reference: Brown, R. E., Demonstration of Acceptable Systems for Land Disposal of Sewage Sludge. Water Engineering Research Lab, EPA 600/Z-85-062, Cincinnati, OH, U.S. EPA, 1985.)

62. Are there any sites in NYS that have shown adverse affects resulting from sludge applications under current regulations?

Nutrients:
63. If nitrogen loading calculations provide the limitation for application rates, doesn't that raise the potential for phosphorus pollution?

JF. Since nitrogen is mobile in soils and phosphorus is not, the potential for off-site migration of phosphorus is restricted to the movement of soil itself. Therefore, the potential for such off-site migration is associated with soil erosion which is reduced by the application of an organic binding material such as biosolids, and which is subject to management practices which further ensure that soil particles will not move off-site.

JHP. Yes it does, but the relationship between increasing soil P and eutrophication downstream is inexact.

64. Is there any proposed means to prevent phosphorus pollution from sludges?

JF. As noted in the response to the previous question, phosphorus movement is associated with soil erosion; and the management practices (e.g., setbacks, slope restrictions) imposed on land application, along with the organic nature of the phosphorus contained in biosolids, prevent such movement.

JHP. Yes, keep soil pH 6.5-7, apply sludge to low-runoff soils, quit applying P-rich (relatively to N) sludges when soil P level exceeds a still-to-be determined point.

Water:
65. What are the risks to ground and surface water and what can be done to protect them?

JF. The combination of requiring agronomic rates to control nitrogen application and management practice restrictions which prevent the movement of soil (and its associated phosphorus) off-site insure that the land application of biosolids will be conducted with no risk to ground and surface waters. Metals, pathogens and trace organic compounds are all adsorbed (bound) in the soil complex and do not move to ground or surface water.

JHP. Risks are real for nutrient, metals, pathogen contamination of water from sludge application and about equivalent to those from manure for nutrients and BOD. Manure has very little risk of metal pollution of surface waters, while sludge does if not incorporated. Once in the soil, some risk of groundwater pollution by pathogens or metals if shallow groundwater situations, but risk for groundwater below 5-6 feet in a silt loam or clay loam soil slight.

EZH. Good management is important in preventing water pollution. Setbacks from watercourses, avoidance of steep slopes, incorporation into the soil, maintaining a vertical separation from groundwater, and maintaining a near neutral pH are among the practices which should be followed.

GNL/WMS. Contamination of groundwater by nitrates in biosolids has been addressed through the requirement that biosolids must be applied at or below the agronomic rate of the crop to which the biosolids are applied. Surface waters are protected through the management practices contained in §503.24; one such example is the requirement that biosolids can not be applied on a site that is 10 meters or less from water so the United States. In addition, biosolids can not be applied to sites that are flooded, frozen or snow-covered to prevent biosolids from entering wetlands or other waters of the United States.

66. What is the required or recommended depth to ground water for Class A sludges? Class B?

JHP. 24 inches for seasonal high water table.

GNL/WMS. The Part 503 regulations do not have a general requirement or management practice regarding the recommended depth to groundwater for biosolids. The Part 360 regulations restrict land application of biosolids in areas where the seasonal high groundwater is within 24 inches of the ground surface. In addition, land application of biosolids can not occur in areas where an aquifer or wellhead protection area is within 60 inches of the ground surface.

67. Have there been any instances of a farmer having problems such as groundwater contamination resulting from land application?

JF. No such problem has occurred under the appropriate management conditions which are required for land application. Over-application of any nitrogen source is a potential problem with respect to groundwater, and the agronomic rate required for land-applied biosolids is the means of preventing such over-application.

JHP. Not that I know of from sludges, but yes from improper manure and nitrogen fertilizer applications.

Phytotoxic effects:
68. What are risks to high value, permanent crops (like citrus, stone fruits) on non-mid-Western soils since risk assessment largely addressed corn and grain on mid-Western soils?

JF. The Part 503 pollutant limits were set to preclude phytotoxicity (reduction in plant growth) by several different procedures. Data on sensitive crops (i.e., those more subject to yield reduction) were used to define phytotoxic effects and limit metal applications from biosolids to levels below the phytotoxicity threshold. These limits were determined across a broad variety of crops and soil types including acid soils of the Northeast, and protect even the most sensitive crops. (Reference: A Guide to the Biosolids Risk Assessment for the EPA Part 503 Rule, U.S. EPA Office of Wastewater Management, EPA 832-B-93-005, September 1995)

JHP. Risks to the crop plants are small, as bush and tree crops are relatively insensitive to metals, and rooting patterns avoid soil areas where sludge usually applied.

Other:
69. Are odors a significant concern? If so, what can be done to address them?

EZH. Yes, odors are one of the most problematic aspects of sludge use. Sometimes odors are caused by stockpiling of sludge or sludge products, so prompt spreading can help to minimize odors. Incorporation in the soil also helps to prevent odors.

LIABILITY
70. Why would a farmer take the risks associated with sludge application?

JF. Thousands of farmers across the US view the application of biosolids as less risky than their other agricultural practices, and the benefits to be derived from a free or low-cost fertilizer can be very significant to farmers participating in land application programs--frequently up to $100/acre, which represents approximately double a typical farmer's net income on the areas where he uses biosolids.

JHP. A farmer would like to improve his soil rooting and nutrient properties by adding organic matter, and presumably because of financial incentives (cheap fertilizer, cash payment).

GNL/WMS. If the sludge is properly treated and meets the requirements set forth in the federal and State regulations, it is New York City's opinion that land application of sludge does not pose a risk to the farmland or farmer.

71. If a farmer's land becomes contaminated due to sludge application, who is responsible for clean-up?

JF. The question assumes a contamination which has never occurred since biosolids quality standards and regulations are established to prevent such an occurrence.

JHP. The farmer is.

EZH. Liability is generally complex and would be determined in court. There would be a lot of finger pointing and attempts to determine the cause. Was it bad quality sludge (in which case the generator or vendor would bear more responsibility)? Was it inappropriately applied (making the applicator or farmer responsible)? If the farmer declares bankruptcy and the land reverts to a bank or lender, they might become responsible.

72. What is the stance of bankers, insurance companies, and title insurance companies towards farmers who use sludge on their lands?

JF. When such organizations evaluate agricultural properties, the use of biosolids is viewed in the same context as the use of other agricultural products if done in accordance with applicable state and federal regulations.

EZH. This seems to vary in different areas of the country. In some areas the lenders don't seem concerned, in others they want to have the farmers enter into an indemnification agreement with the sludge generator and vendor.

73. What kinds of indemnification are there and how do they protect the farmer?

JF. Indemnification agreements are sometimes used to document the responsibility of the generator (for biosolids quality), the land applier (for adhering to operational requirements for applying biosolids) and the farmer (for observing temporary access and crop restrictions). Such agreements provide a means for farmers to insure that the responsible parties (i.e., the generator and contractor) will defend, if necessary, against any legal action which alleges that biosolids were improperly produced or applied to their farms.

EZH. Indemnification agreements specify who is responsible for what. So, for example, they might say that the sludge generator and vendor are responsible for providing a sludge that meets quality standards and the farmer is responsible for application according to best management practices. The problem with these agreements, however, is that were some contamination to be discovered and a law suit brought, it would be very difficult to pinpoint the cause, especially since discovery would be likely to be several or many years after application.

74. What, if any, is the farmer's liability in using sludge?

JF. As described in the responses to the previous questions, a farmers potential liability from biosolids is significantly less than the potential liability he incurs through his normal farm operating practices.

EZH. All of us are liable for things which take place on our property. Many of us carry homeowners insurance in part because someone may hurt themselves on our property and sue us. Similarly, a farmer is liable, to the extent determined by a court, for injuries that may be caused by sludge use, or for any other practices on the farm. Because of the potential for neighbors to be particularly concerned when sludge is applied, this higher level of concern may increase the likelihood of complaints regarding sludge application practices.

75. If a drinking water treatment sludge cannot be land applied because of high aluminum content, why can a sewage sludge with higher levels of aluminum be land applied?

JF. Most aluminum-containing drinking water sludges represent little or no benefit to a farmer and therefore would not be eligible for land application. Levels of aluminum in biosolids are generally low compared to those in water treatment sludge; and in any case, since aluminum is already a significant component of the soil matrix, additions of biosolids at an agronomic rate would not be detectable to virtually any soils since soils themselves typically contain three to ten percent aluminum (60,000 - 200,000 lbs./acre).

76. Under a non-degradation approach to sludge policy, would any land application be practiced? What is being done regarding land application in areas (some of Europe and Canada) where non-degradation standards are in place?

JF. Biosolids and many other common agricultural products would be banned from application to the land under what has been called "a non-degradation approach." Several European nations have undertaken this approach which is based on preserving a soil's current condition (natural background level). Such an approach does not require the detailed knowledge about the fate and transport of pollutants, exposure analysis and dose response relationships which is entailed in developing permissible pollutant concentrations for soils based on the soil's capacity for assimilating, attenuating and detoxifying those pollutants to minimize risks to humans, agricultural crops and the environment (the U.S. 503 approach). Under this latter scenario, the agronomic benefits of biosolids can be realized without harming soil quality, public health and the environment which is usually not possible by the simple mass balances of the "non-degradation approach." The selection of the risk-based approach is a policy decision on the part of the U.S. and reflects our commitment to recycling along with the huge infrastructure and capital expenditures associated with wastewater treatment and pretreatment programs in this country.

JHP. It could be, as soil mixed with high-quality sludge would dilute out the metal concentration to or below the no-degradation standard. Limited number of applications however.

EZH. One of the goals of those supporting a "non-degradation" standard is to maintain a pressure towards continued improvements in sludge quality. Once sludges have achieved the "EQ" 503 standards there is no incentive for lowering contaminant levels, particularly since there are no labeling requirements so that consumers could not easily compare between different products and select the cleaner one. Meeting standards based on uncontaminated background soils would be feasible for some contaminants and very difficult for others. One suggested approach has been to phase in such "non-degradation standards" over a number of years, giving sludge generators time to decrease contaminant levels.

77. Are there any sludges generated in western NYS being land applied?

EZH. Yes, for example the City of Bath Class B sludge is being land applied.

78. Is the Albion, NY treatment plant landspreading its sludge?

79. Will Cornell's soil lab offer testing for soil metals as part of soil nutrient analysis?

JHP. The Cornell soils lab offers metal testing but at additional cost to the nutrient analysis.

80. Will "Cornell Recommends" address sludge application?

JHP. Yes. We are hoping to include such recommendations in the next revision.

81. Is NYC continuing to contract for land application in Texas? If so what is cost/ton?

GNL/WMS. Currently, New York City is in the process of evaluating technical and cost proposals from a number of contractors for direct land application of biosolids and biosolids processing (e.g. composting, lime stabilization, pelletization). The contracts will be in effect starting July 1, 1998. At this point, New York City cannot divulge the location and costs associated with these proposals without jeopardizing the integrity of the process. Suffice to say, it is New York City's goal to have the most flexible and reliable biosolids management program possible, both operationally and economically, with the potential to apply biosolids anywhere in the United States. To meet this end, it is predicted that New York City will employ the services of a number of contractors offering different biosolids management practices.

82. Is Wheelabrator-Bio Gro owned by Waste Management Inc.?

JF. Yes. Wheelabrator is a publicly traded company, a majority of whose stock is owned by WMX Technologies Inc.

GNL/WMS. Yes.

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Updated January 1999