Recommendations for Municipal Sludge Ordinance/Rules

May 2003 DRAFT

Prepared by


Ellen Z. Harrison, Director, Cornell Waste Management Institute

Ithaca, NY 14853

607-255-1187 · ·


These recommendations do not represent the position of Cornell University.  They represent the expert opinion of the drafter.  They are derived from the research, knowledge, expertise and opinion of the drafter, with input from colleagues.

General Notes:

The authority which municipalities can exercise varies from state to state, thus in some states some of the suggested provisions may not stand up to legal challenge.  The particular state legal framework under which the municipality operates is an important consideration.  Careful language in drafting the ordinance will also help to avoid successful legal challenges to an ordinance.

The particular concerns that a municipality seeks to address through an ordinance will vary and the provisions of the ordinance can be tailored to focus on those concerns.  However, in this document, many of these recommendations are linked.  For example, the suggested contaminant concentration limits for the phytotoxic metals (Cu, Ni, Zn) are based on calculations having to do with the limit in the total quantity of sludge that may be applied at any site.  Thus the combination of these two provisions – maximum concentration and quantity applied - would limit the total cumulative amounts of these metals that could be applied over time which would prevent reaching phytotoxic levels in the soil.  If only one of these provisions was included, or if it were modified, then the outcome might not reflect the intended outcome in this draft.

Bagged products and products distributed for residential use may be a potential health concern for users.  However, the lower volume used and smaller areas covered reduce the concern they pose to the environment and to other members of the public.  Hence this document does not address such products. Rather is addresses “bulk application” of biosolids defined as application of one ton or more to any piece of property. 

Recommendations are based on dry weight.

Septage is the pumping from domestic septic tanks.  It contains pathogens and chemical contaminants.  Less stringent treatment for pathogens and less testing for contaminants is required for septage than for sludges.

The type of treatment and processing effects sludge characteristics.  As a Class, Class A biosolids differ from Class B only in the extent of treatment to reduce pathogens. Thus, concerns based on chemical contaminants and endotoxins persist in Class A biosolids.  Endotoxins are part of the outer membrane of the cell wall of both pathogenic and non-pathogenic Gram-negative bacteria.  Endotoxins are toxic to most mammals.  Some Class A products remain unstable, and may cause odors when wetted.


These recommendations are based on the premise that it is prudent to use a cautious approach to spreading sewage sludges in order to protect human health, the environment and agricultural productivity because:

sewage sludges contain a complex mixture of chemicals and biological contaminants that is not well characterized and for which it is not possible to adequately assess risks;

some of these chemicals are persistent, bioaccumlative toxics that will remain in soils for many years;

the potential interactions between the chemicals and between the chemicals and biologic contaminants are not known but may be important;

sewage sludges have the potential to contain a wide array of human pathogens and biological agents and it is not feasible to test sludges for all of these;

fecal coliform and salmonella are used as pathogen “indicators” but are not adequate surrogates for other pathogens including some viruses or for endotoxins;

federal and state enforcement and oversight are not adequate to ensure compliance.

Reports of illness in residents, school children and pets that have been associated with sludge spreading show very similar patterns of symptoms. Most, but not all, of the reports of illness associated with land application of sludges of which we are aware appear to be related to application of Class B sludges.

Potential paths of exposure to sludge contaminants (chemical, pathogen and endotoxin) exist for these receptors including air and runoff.  The risks posed by these pathways of exposure for these receptors have not been assessed.  Monitoring of sludges, air, soil and runoff has been very limited.  The number of different chemicals and biological contaminants that are potentially in sludges is large, while the number tested for is small.  Things which are tested for are usually tested only infrequently, so there will usually not be data on a particular batch of sludge applied.  Thus some of the recommendations are to require monitoring to at least begin to develop the needed data.

Management practices and setbacks

There are insufficient data to definitively establish the relationship between risk and management practices.  For example, calculating the risks associated with different setback distances from wells, people, water courses, etc. for spreading of sludges is not possible given the present state of knowledge.  Thus, there are inadequate data to suggest what management practices will be adequate to protect health and the environment.  There are few if any research projects underway to help define these risks and management measures. Policy and practice will not wait, so the numbers suggested herein are based on the application of a precautionary approach overlaid onto professional judgement and reading of the available literature.

The 3 mile proposed setback from occupied buildings to Class B application sites, should Class B not be banned outright, is based on an extrapolation from risks calculated for viral infection.

Limit on cumulative amount and areal extent

Risks posed by land application are related to the exposure – both dose and duration.  In some areas, the use of sludges over large acreage results in frequent (in some areas nearly continuous) potential exposure of surrounding populations.  It also results in heavier loading to the environment in one location, thus increasing the potential “dose” to the water, air, flora and fauna in that area.   Similarly, the total loading of sludge applied on a piece of land is directly related to the “dose” that people and the environment are exposed to. This is one reason that the proposed provisions below suggest limiting the total amount that may be spread on any piece of land as well as the areal extent of spreading. 

Concentration limits

These recommendations pertain only to the agricultural use of sludges and not to use in home gardens.  Risks associated with persons ingesting sludges through hand-to-mouth contact or through the eating of produce grown in sludge-amended soils are thus not part of the analysis used to develop these recommendations.


Maximum recommended soil concentrations for selected elements resulting from sludge application can be found in recommendations put forward elsewhere (Penn State NE Guidelines; Field Crop Recommendations, Cornell Cooperative Extension available on the Cornell Waste Management Institute WWW site:  For some elements (Cu, Ni, Zn) the recommendations depend on soil type.  For these recommendations, calculations have been performed to relate those soil concentrations to maximum contaminant concentrations in sludges under various assumptions (see spread sheet/table at the end of this document).  The concentrations depend on soil type (for some elements), background levels of these elements in the soil and how much sludge is applied.  Thus it is critical that a limit on the total cumulative amount of sludge that may be applied to a piece of land be part of the ordinance.  If larger quantities of sludge may be applied than proposed herein, then the concentration of contaminants in sludges that may be applied must be lower to achieve the same degree of protection since the final soil concentration is a function of both the concentration in the sludge and the amount of sludge applied.


In addition to considering the soil loading as described above and calculated in the spread sheet, where the calculated allowable maximum concentration is higher than typical sludge quality, the allowed concentration limit in an ordinance might be set at the average level in sludges.  Since many contaminants are not tested for, this may help to ensure that only relatively cleaner sludges are used and may help to limit application of other contaminants.

Chemical standards and monitoring

The proposed provisions below include standards for some additional parameters and also more restrictive standards for some of those currently regulated. They also recommend more extensive monitoring than is currently required.  The data collected through such monitoring will help to form a basis on which future regulations can be developed.  They will also provide information about the potential impact to the lands on which the sludges are spread.

Current rules establish a frequency for monitoring of sludges based on the flow through the wastewater treatment plant.  In some cases, testing may be as infrequent as annual for small facilities.  Variability in sludge quality is a concern.  Smaller facilities may have more variable sludges than larger ones due to the potential that only a few industrial facilities may be discharging into the system and particular activities there may impact sludge quality.  Thus a minimum of quarterly testing is suggested below.

Current requirements for monitoring of land applied sludges are very limited.  Current federal rules set standards for and require sludges to be tested for a very short list of parameters.  In addition, there is a lack of data regarding the concentrations of various biologic and chemical contaminants in sludges.  .

Data on sludge quality are also very limited.  The current federal rules are based on a survey of sludges done in 1988.  That survey had analytic deficiencies and did not include many chemicals that are of potential concern in sludges today. 

There are few data on the concentration of organic chemicals in sludges and there are no federal standards for any organic chemicals in sludges.  Because many of these chemicals are contained in waste water and because many will tend to concentrate in the sludge, data are needed on their concentration in order to consider the need to regulate them.  The provisions below suggest adopting some standards for organic chemicals (largely based on standards in some European countries).  They also suggest that monitoring be required for sludges so that we can begin to obtain the data needed on sludge quality. 

Current regulations and testing are not adequate to determine whether Class A biosolids achieve and maintain high-level disinfection.  Thus monitoring Class A sludges for disinfection is suggested.

Soil incorporation and pasture

Two potential routes of exposure of people to the pathogens, endotoxins and contaminants that may be in sludges that have not been assessed are wind borne air transport of both gases and particulates and water borne runoff.   While data are not available, it is likely that these exposures would be greater for sludges applied to the land surface and not incorporated into the soil.

Animals eat soil (the amount varies with the animals and with the site conditions and availability of other food). The persistent bioaccumlative toxic chemicals present in sludges tend to accumulate in the fats of animals, such as their milk and meat. Application of sludges to the soil surface where animals graze, such as in pastures, is likely to increase the percentage of sludge ingested by these animals. 

Sludge odors can be a major problem.  Incorporation and prohibition of stockpiles are likely to reduce odor potential.

Hence incorporation and prohibition of application to pasture are among the recommended provisions below.

A trade off associated with incorporation may be that the degradation of some organic chemicals and die-off of some pathogens may be reduced when sludges are incorporated into the soil.  Since these proposed provisions would eliminate the application of pathogen-laden sludges, that should not be a concern for pathogens but remains an issue for organic chemicals.


The current rules do not take into account current understanding of how contaminants may move through soils.  Examples are such processes as macropore flow (rapid movement through holes in the soil created by worms, roots, freezing/thawing, etc.) and facilitated transport (contaminants moving by “tagging along” with other more leachable constituents).  Recent research suggests not only that sludge-borne contaminants may leach, but that sludges increase the leaching of pesticides.

The risks to the quality of water in wells in the vicinity of sludge application sites is likely low if recommendations concerning the type of sludge, limitations in amount of sludge applied and sludge quality are followed.  If they are not followed, then any wells used for water supply for people or animals within approximately one mile should be tested for pathogens (including viruses), metals and nitrates before biosolids are applied (perhaps funding should be provided so local health can do this), and quarterly thereafter.  If tests of the biosolids confirm absence of pathogens, the pathogen testing might be reduced to annual testing.

Slope and soil class

Application to steeply sloping, low permeability soils increases the likelihood of runoff.  Thus reference is made to restricting spreading on such soils as identified in a soil survey classification. {The specific soils and soil survey information for the particular county or municipality should be considered.}

Permit requirements

Under federal rules, sludges are to be applied according to the calculated nitrogen requirements of the crops being grown.  However, due to the nitrogen to phosphorus ratio in sludges, if appropriate amounts of nitrogen are applied, phosphorus is usually excessive.  Hence it is recommended that rates be calculated on the basis of N and P, which ever is more restrictive. 

There is some indication that at some sites, calculated application rates are based on optimal crop yield, while application is on marginal lands with far lower yields and thus sludges may be over applied.  Thus the suggested requirement below to require submission of a plan and of annual reports by certified professionals.  Due to requirements under the CAFO (confined animal feeding operation) rules, nutrient management plans and certified planners should be available.

Record Keeping

Under current rules, no records or registration is required for use of Class A EQ sludges.  With the exception of pathogens, Class A sludges have the same concerns as Class B.  Hence some food producers are interested in knowing if sludges have been used in the past on land from which growers are harvesting.  Given the few data on the chemical contaminants in sludges, we may find a need in the future to identify lands which have been sludged.  Lands to which Class B and non-EQ sludges have been applied should be identified in documents submitted to the USEPA, but this information is not accessible to persons interested in a parcel of land (a potential purchaser or food processor for example) unless they know that sludge was applied and they seek reports for that particular site from the USEPA.  Thus it is proposed that information regarding sludge use be entered into the land records.


Federal and state staffing is insufficient to ensure that sludges are spread according to the applicable rules.  Thus local enforcement is needed.  Funding to provide for the inspection and enforcement can be generated through permit fees.  These recommendations are included below.

Proposed Ordinance Provisions:

Ban Class B which has the potential to pose pathogen risks

Everywhere (or at least within 3 miles of occupied buildings including places of employment)

Where there is a need to protect groundwater and surface water resources from pathogens (i.e. Over groundwater recharge areas, within a mile of wells used for drinking water for humans or animals, within watershed in which surface waters are used for drinking water supplies).

Ban Septage which has the potential to pose pathogen risks

Everywhere or at least within 3 miles of occupied buildings including places of employment.

Where there is a need to protect groundwater and surface water resources from pathogens.

Ban or restrict Class A products unless they can be shown to be:

stable and not to create objectionable odors when wetted;

achieve high level disinfection.

Limit frequency of application and total amount

maximum which may be applied to any land in a period of 3 years is 10 tons/acre. 

total amount that may be applied to any piece of land shall not exceed 60 tons/acre.

The proportion of land receiving biosolids shall not exceed ~5% of the watershed of any second order or higher stream.

Prohibit application over significant aquifers or ground water recharge areas.

Prohibit application on lands subject to flooding in a flood event with a 25 year or more chance of occurrence.

Prohibit application in areas with soil classifications falling into Class C or D and require contour disking where soil classifications are not Class A.

Only allow application in agricultural areas and/or within certain zoning districts.

Prohibit application on food crops and on pasture.

Prohibit application of any sludge product (including Class A) within 500 feet of occupied buildings (both residential and workplaces).

Require land applied sludges to meet stricter standards for inorganic elements than 503 Table 3.

Limiting the concentration in the final soil is the goal.  To calculate the recommended maximum level in sludges, the amount of increase over background levels in the soil and the total amount of sludge that may be applied are taken into account.  The table below shows the results of such calculations.  If a greater quantity of sludge was applied to the land, then the concentration of the contaminant in sludge should be reduced to maintain the same final soil concentration.

These soil limits depend on the soil type for some elements (Cu, Zn, Ni, Mo). 


Calculations of Recommended Maximum Concentrations of Contaminants in Sludges based on Recommended Maximum Soil Concentrations*


in ppm










Recom max soil conc (sandy)**










Typical ag soil






















Recom max sludge conc at 60T/ac










sludge conc at 30T/ac





















Recom max  soil conc (sandy-silty loam)









Typical ag soil






















Recom max sludge conc at 60T/ac










sludge conc at 30T/ac





















Recom max soil conc (silt/clay)










Typical ag soil






















Recom max sludge conc at 60T/ac










sludge conc at 30T/ac





















Part 503 Table 3 Sludge limits












Typical NYS sludge

3 to 10




1 to 10

5 to 50

2 to 15

2 to 6


*A range is provided for several elements and the spread sheet provides calculations based different parts of the range.

** These recommendations are for final soil concentrations and are from a combination of recommendations contained in: Criteria and Recommendations for Land Application of sludges in the Northeast, 1985. Penn State U, Bulletin 851 and the 2002 Cornell Guide for Integrated Field Crop Management. Cornell Cooperative Extension.


Thus if soils in the municipality are sandy, and the total cumulative amount of sludge is limited to 60T/acre, then a sludge could have up to 333 ppm of copper without exceeding the maximum recommended copper level in the soil.  If cumulative application were capped at 30T/ac, then sludge concentration could be 667 ppm of Cu.

Require incorporation of all land applied biosolids within 8 hours of delivery.

Prohibit stockpiling.

Composts applied shall be stable and mature or highly mature.

Require site specific permits for all bulk applications (including Class A).

Record bulk sludge applications on permanent and accessible land records.

Include neighbor notification and a possibly a hearing as part of the permit process.

Permit valid for 3 years, expires if not exercised within a year of approval.

Land spreading plan submitted and approved annually.

Odor control plan be included in the management plan for every permitted site that addresses how the permitee will prevent objectionable odor or abate it if a complaint is received.


Co-permitees include the generator, transporter, applicator, operator, and owner.

Or if only one entity is permitee, require the signature of the other parties on a disclosure statement indicating that they know what biosolids are and that they agree to their use.

Require indemnification statement from generator and applier stating that they certify that the materials applied and the application methods will comply with the requirements and that all liability for pollution caused by biosolids, that was otherwise legally applied, shall be borne by the sludge generator.

Prior significant non-compliance with environmental laws at federal, state or local level or lack of responsibility as shown by past work by the applicant is grounds for permit denial.

Testing and reporting

The frequency of biosolids monitoring shall comply with 503 or state rules, whichever is more stringent.  However in no case shall monitoring frequency be less than quarterly.

Limits of detection and methods shall be reported for all tests.

Test parameters

Testing for inorganic elements in biosolids shall use EPA approved methods and shall include:

Arsenic, beryllium, boron, cadmium, chromium, copper, lead, mercury, molybdenum, nickel, selenium, silver, sulfur, zinc.

Each batch of biosolids delivered shall be tested immediately before soil incorporation for endotoxins.

Each batch of biosolids delivered shall be tested immediately before soil incorporation for stability and composts shall be tested for maturity. 

At least annually biosolids shall be tested for radioactivity and for organic chemical contaminants including EPA semi-volatiles (using EPA approved methods or equivalent), PAHs, chlorinated pesticides, brominated diphenyl ethers, nonylphenols and related compounds, linear aliphatic sulphonates, triclosan, methyl triclosan, PCBs, musks, dioxins and furans.  In addition, the 25 highest peaks that are found in the GC/MS scan for the semi volatile priority pollutants shall be identified.  The findings shall be discussed in the annual report and the concentrations shall be compared with other standards for these chemicals (such as soil screening levels).

Permit requirements and conditions

Certified agricultural professionals to submit plans and to certify post-application that application was according to the plans.

Nutrient management plan required for all bulk applications – including assessment of N and P. Crop specific. If the crop grown changes, then a new plan is required.  The plan should take into account the current nutrient status of the soils (based on soil testing) and all of the sources of nutrients contributed to the site.

Application is limited to once per crop cycle.

Water quality management plan required for all bulk applications to prevent impacts to ground and surface waters.

Require notification of the permitting authorities 48 hours prior to delivery of biosolids to the site.

Prohibit application and incorporation during winds >5mph.

Prohibit application and incorporation at times of year when ground is frozen or when soils are within 75% of field moisture capacity.

Prohibit application during rainfall or when significant rain is predicted within 24 hrs.


Any violations of the permit or excursions from the approved plans will be reported within 12 hours of their discovery.  This includes significant rainfall occurring within 24 hours of application.

File report within 60 days of application stating source, treatment method and quality of biosolids, quantity applied and how they were managed on-site.  Include certification by registered professional that biosolids were applied according to the approved permit and land spreading plan.

File annual report that includes certification by registered professional that biosolids were applied according to the approved permit and land spreading plan; results of any required monitoring, including annual medical screening of workers to detect sludge-related injuries or diseases; copies of any informational materials provided to workers, farmers, neighbors; any complaints received and how they were handled;

Vehicles and transportation

Require trucks to be plainly labeled with contents and with contact information for responsible party.

Require trucks to be covered.

Prohibit tracking of biosolids onto roadways.

Consider limiting the roadways that may be used to move the biosolids.

Time of operation

Consider limiting the time of day during which delivery and spreading may take place.


            The permit authority or its delegee has the right to:

Obtain and analyze samples;

            Inspect vehicles, facilities, monitoring equipment

            Have access to and copy records

            Obtain photographs

            Interview employees.

By reference require compliance with federal and state sludge rules.

Permit or approval of spreading plan may be revoked if violate any provision of the permit or for any violation of this rule, of any federal or state laws or regulations.

Sanctions for non-compliance must be substantial. Civil fines should be meaningful as to amounts, and graduated based on knowledge, severity of violations, past violations, profits realized by noncompliance, etc. Criminal penalties (including jail terms) should be available for repeated offenses, “reckless endangerment,” severe environmental impacts, etc. Natural resource damages should be recoverable in case of ecosystem damages.

Co-permitees are jointly and severally liable for all damages that may be caused by sludge application (whether legally applied or not) as well as any cleanup and remediation that may be ordered by relevant governmental authorities.

Establish enforceable odor standard.

Establish and require a procedure for receiving and handling complaints:

Who should complainants contact and how;

What is the system for and who is responsible for recording complaints;

What is the system for and who is responsible for investigating complaints;

What is the system for and who is responsible for responding to complaints.

Require posting of signs at bulk application sites

            Signs to include

What is being spread

By whom

information on who to contact if complaint

Multi-lingual if appropriate.

            Specify distance between signs along site boundaries – perhaps 50 feet between signs.


            To cover inspection, testing, road clean up and maintenance.

Require insurance coverage for environmental or health harm.

Require bond or proof of liability coverage. The initial bond or insurance coverage, which must be provided by one or more of the permittees, should cover potential cleanup-remediation costs, natural resource damages, and a medical surveillance fund to ensure that farm workers will receive an annual physical examination to detect sludge-related injuries or diseases.

Farm Worker Health

Require sanitary facilities including hand washing stations.

Require information provided to workers regarding health potential health risks associated with biosolids and measures to reduce those risks.

Provide annual medical screening of workers to detect sludge-related injuries or diseases.

Severability clause – if any section of the law found invalid, does not invalidate other sections.




2003 Cornell Guide for Integrated Field Crop Management. 2003. Cornell Cooperative Extension.


Criteria and Recommendations for Land Application of Sludges in the Northeast. 1985. The Pennsylvania State University. Bulletin 851.


Dowd, S.E., C.P. Gerba, I.L. Pepper, and S.D. Pillai. 2000. Bioaerosol Transport Modeling and Risk Assessment in Relation to Biosolid Placement. Journal of Environmental Quality, 29:343-348.


Harrison, E.Z. 2000. Comments to US EPA Regarding Dioxin Standards for Land Applied Sewage Sludges.


Harrison, E.Z., M.B. McBride, and D.R. Bouldin. 1999. Land Application of Sewage Sludges: An Appraisal of the U.S. Regulations. International Journal of Environment and Pollution, 11:1.


Harrison, E.Z. and M. Moffe. 2003. Septage Quality and its Effect on Field Life for Land Applications. American Water Resources Association, 39(1):87-97.


Harrison, E.Z. and S.R. Oakes. 2003. Investigation of Alleged Health Incidents Associated with Land Application of Sewage Sludges. New Solutions: A Journal of Environmental and Occupational Health Policy, 12(4):387-408.


National Research Council. 2002. Biosolids Applied to Land: Advancing Standards and Practices. National Academy Press, Washington, DC.


U.S. Environmental Protection Agency, Office of Inspector General. 2000. Biosolids Management and Enforcement. Audit Report No. 2000-P-10.


U.S. Environmental Protection Agency, Office of Inspector General Status Report. 2002. Land Application of Biosolids. 2002-S-000004.