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Toxics Release Inventory Tells Its Own Sludge Story

September 6, 2008

The US Environmental Protection Agency (EPA) uses the terms “sewage sludge” and “biosolids” interchangeably.  Hereinafter this substance will be called “sludge”.

The waste industry and EPA dismiss the hazardous chemicals in sludge as low concentrations of “microconstituents”.     Over 90,000 chemicals are used in industry and commerce in the United States.    Every one of them can end up in public sewers where the wastewater treatment process reconcentrates them in the sludge.  

The EPA’s Toxics Release Inventory for 2005 lists the following discharges to sewage treatment plants:

 262,904,056 pounds of Non-metals – industrial chemicals to POTWs
1,735,360  - pounds of Metals and metal compounds to POTWs
 Dioxin & Dioxin like compounds to POTWs   99.9313 pounds

However, the Environmental Working Group, General Accounting Office and EPA state that those TRI numbers represent ONLY 5% of the actual chemical discharges.    Thus, the true total of hazardous wastes dumped into public sewers is over 5.3 billion pounds each year.    In addition to industrial discharges, the EPA also allows landfills and Superfund Sites to dump their toxic leachates into sewage plants.

The only sludge testing is for 9 metals . . . . the other 85,000 – 90,000 chemicals are untested, unregulated and unmonitored.   And there is no research on risk to human and animal health and the environment from chemical mixtures and interactions which occur in sludge.

Greg Kester, Wisconsin, National Biosolids Coordinator:  ““Since the purpose of wastewater treatment is to remove pollutants, it is not surprising that a complex mixture of material winds up in the sludge,” said Kester.

Research by Cornell University Waste Management Institute found that toxic organic (carbon based)  chemicals can be at such high levels in some sewage sludges that they exceed the EPA's Superfund Soil Screening Limits (SSLs).

" Using default values for a residential exposure scenario, the EPA risk-based SSLs address exposure pathways including direct ingestion of contaminated soil, inhalation, dermal
exposure, drinking of groundwater contaminated by migration of chemicals through soil, and ingestion of homegrown produce contaminated via plant uptake (U. S. Environmental Protection Agency Superfund, 1996)."

Classes of chemicals found in sludge which exceeded the EPA's Superfund Soil Screening Levels include Aliphatics, Chlorobenzenes, Monocyclics, Nitrosamines, Pesticides, Phenols, Phthalates and PAHs.   None of these chemicals in sludge are monitored or regulated by the EPA.

 Cornell report:  "Data were found for 516 organic compounds which were grouped into 15 classes.   Concentrations were compared to EPA risk-based (superfund) soil screening limits (SSLs) where available.   For 6 of the 15 classes of chemicals identified, there were no SSLs.  For the 79 reported chemicals which had SSLs, the maximum reported concentration of 86% exceeded at least one SSL.   Eighty-three percent of the 516 chemicals were not on the EPA established list of priority pollutants and 80 percent were not on the EPA's list of target compounds. Thus analyses targeting these lists will detect only a small fraction of the organic chemicals in sludges."

The reason local sewage plant operators aren’t enforcing industrial pretreatment programs is because they fear the added expense of properly disposing of, or recycling, toxic chemicals would force industries to relocate to countries such as Mexico with weak or nonexistent environmental and labor laws.    This could result in US job losses and a blow to the local economy.

In 2004, the EPA Office of Inspector General issued a report documenting the failure of pretreatment programs to keep toxic pollutants out of sludge.

“. . . the performance of EPA's pretreatment program, which is responsible for controlling these discharges, is threatened and progress toward achieving the Congress' Clean Water Act goal of eliminating toxic discharges that can harm water quality has stalled.”

“. . .  Toxic pollutants are still being transferred to sewage treatment plants, and the impact to human health and the environment of some of these pollutants may still not be known."

“   One possible explanation is that EPA Regions and State agencies that are supposed to act as control authorities for POTWs without approved programs do not have standards for overseeing industrial users discharging to these POTWs.   Although EPA was working on necessary guidance for these Regions and States, the project was put on hold due to other priorities."

“There are hundreds of thousands of industrial users in the United States, and many may discharge toxic pollutants to wastewater facilities."

Federal law allows every business and industry in the United States to dump 33 pounds of hazardous wastes into public sewers each month with no reporting requirements.    Industry is allowed to dump ACUTELY hazardous wastes, or quantities exceeding 33 pounds, with only a one-time notification to the sewage plant.    [ 40CFR 403.12)P)(2) ]

EPA permitted toxics in sewage sludge   

Thus, official government policy appears to support disposal of residential, business and industrial chemical wastes into public sewers, to end up in the sludge being spread on agricultural land.   Therefore, the solution may be to follow Europe’s lead and upgrade and utilize one of the many thermal and other technologies available to convert sludge from a contaminated waste to a renewable resource to cleanly generate biogas, biomass, electricity, steam, and other types of energy and power, protect farmland, reduce greenhouse gases and reduce dependence on foreign oil.

Respectfully submitted,

Helane Shields, sludge researcher since 1996

PO Box 1133, Alton, NH 03809   603-875-3842