5 CCR 1002-63.70 Statement of Basis and Purpose (July 1, 1989)

• Library: Colorado Administrative Code
• Edition: 2023
• Currency: Current through Register Vol. 46, No. 24, December 25, 2023
• Citation: 5 CCR 1002-63.70
• Year: 2023

This is a statement of Basis and Purpose for adopting the regulations entitled: "Pretreatment Regulations".

A. PURPOSE

These regulations apply to non-domestic sources of pollutants, including those in the industrial categories promulgated by EPA which discharge such pollutants to a publicly owned treatment works (POTW) transport them to the plant by truck or rail, or otherwise introduce them into the POTW. Non-domestic pollutants are those pollutants in wastewater from any process or activity of industry, manufacturing, trade or business, from the development of any natural resource, from animal operations, from contaminated stormwater, or leachate from solid waste facilities. The regulations also apply to POTW's which receive wastewater from these non-domestic sources. These regulations do not apply to non-domestic sources of pollutants which discharge to a sewer system not connected to a POTW.

The goal of the pretreatment program is to protect municipal treatment plants and the environment from adverse impacts that may occur when hazardous or toxic wastes are discharged to a sewage system. This goal is achieved through regulating the substances discharged to POTW's. These regulations are designed to prevent the pass-through of pollutants interference of pollutants with treatment plant operations, contamination of sludge, and the exposure of POTW workers to chemical hazards.

B. NEED FOR PRETREATMENT

A pretreatment program is needed to eliminate or prevent several serious problems that can occur when industrial wastewater is discharged into a treatment plant designed to treat domestic sewage. Problems include:

(1) Pass-Through A problem of major concern is the pass-through of toxic pollutants through a treatment plant and into the receiving stream. Since domestic wastewater treatment plants are not normally designed for treatment of toxics, they only partially treat them and the toxics may then be discharged by the POTW to the receiving stream at levels that could cause a violation of stream standards. This could result in degradation of the stream, injury to classified uses, and even render the stream unsuitable as a drinking water source in some cases. EPA estimates that 37 percent of the toxic industrial compounds entering the surface waters of the country do so via a domestic sewage system. Implementation of a pretreatment program, which regulates industry, could drastically reduce pass-through.

(2) Interference Another concern is the possibility of toxic pollutants from industrial discharges interfering with unit processes at a treatment facility and causing violations of the POTW's permit. Toxic or hazardous wastes, in relatively small concentrations, can "kill" the biomass used to stabilize and biodegrade the sewage resulting in the plant being unable to treat the sewage Violations of limits for conventional and/or toxic type parameters could occur leading to a degradation in stream quality. Toxic pollutants which are removed via deposition in the sludge can also cause upsets in digesters resulting in an inadequately digested sludge which may not be acceptable for disposal using cost-effective methods.

(3) Sludge Contamination Most pollutants removed in a domestic facility can be found in the sludge. Pretreatment is needed to assure that toxic or hazardous pollutants do not make their way back to the environment via disposal of sludge. This is of special concern since the toxic pollutants will accumulate in higher concentrations in the sludge. A study by Feilder (1979) showed significant concentrations of priority pollutants in the sludge of a POTW even though these pollutant concentrations were below detectable limits in the plant's influent. If these sludges were disposed of in a sanitary landfill these pollutants may leach out and contaminate adjacent surface and groundwaters. These "toxic" sludges can not be applied under the beneficial use regulations since the crops or pasture grasses produced may not be safe for human or animal consumption, and would need to be disposed of in a hazardous waste disposal site. Through pretreatment these pollutants can be limited prior to entrance into the plant to levels which will not contaminate the sludge This would save POTW's the cost of landfilling and allow the beneficial reuse of the POTW's sludge. The quality of the sludge disposed of will become more important to communities as they face additional restraints on sludge quality when EPA proposes sludge regulations this fall. EPA will address, among other disposal processes, beneficial use, landfilling and incineration. Regulation of industrial discharges to POTW's via the pretreatment program is a vital tool needed to assist in preventing contamination of sludge.

(4) Corrosion Another problem of concern which the pretreatment program can address is corrosion. Highly acidic industrial wastes can corrode piping and equipment in lift stations and sewer lines, as well as in the plant itself. The replacement of these items can be costly. This problem can be greatly reduced by controlling the pH of the wastewater. The Department of Health does not know of any instances of corrosion which can be tied directly to an Industrial User. This does not mean that it is not occurring. The Washington Suburban Sanitary Commission of Maryland has had to replace several thousand feet of sewer line due to corrosion problems from acidic industrial discharges. Implementation of a pretreatment program has enabled the Commission to identify and control these sources (EPA, 1986). The pretreatment regulations, through the specific prohibitions, would limit the likelihood of corrosion and thus save communities money.

(5) Explosions Some toxic pollutants contained in industrial wastes may volatilize in the plant or sewer line. It is possible that the resulting gases...