<P> Standards are set for sewage sludge generated or treated by publicly owned and privately owned treatment works that treat domestic sewage and municipal wastewater . Materials flushed in household drains through sinks, toilets and tubs are referred to as domestic wastewater and include components of soaps, shampoos, human excrement, tissues, food particles, pesticides, hazardous waste, oil and grease . These domestic wastewaters are treated at the source in septic tanks, cesspools, portable toilets, or in publicly / privately owned wastewater treatment works . Alternately, municipal wastewater treatments consist of more levels of treatment that provide greater wastewater cleanup with larger amounts of sewage sludge . Primary municipal treatment remove solids that settle at the bottom, generating more than 3,000 liters of sludge per million liters of wastewater that is treated . Primary sludge water content is easily reduced by thickening or removing water and contains up to 7% solids . Secondary municipal treatment process produces sewage sludge that is generated by biological treatment processes that include activated sludge systems, trickling filters, and other attached growth systems . Microbes are used to break down and convert organic substances in wastewater to microbial residue in biological treatment processes . This process removes up to 90% of organic matter and produces sludge that contains up to 2% solids and has increased generated volumes of sludge . Methods of use and disposal of sewage sludge include the following: Application of sludge to agricultural and non-agricultural lands; sale or give - away of sludge for use in home gardens; disposal of sludge in municipal landfills, sludge - only landfills, surface disposal sites and incineration of sludge . Managing quality of sewage sludge not only involves wastewater reduction and separation of contaminated waste from non-contaminants but also pretreatment of non-domestic wastewater . Pretreatment does not thoroughly reduce pollutants level and therefore communities have to dispose rather than use sludge . </P> <P> Any U.S. citizen may file a citizen suit against any person who has allegedly violated an effluent limitation regulation or against the EPA Administrator if the EPA Administrator failed to perform any non-discretionary act or duty required by the CWA . </P> <P> The CWA includes an employee ("whistleblower") protection provision . Employees in the U.S. who believe they were fired or suffered adverse action related to enforcement of the CWA may file a written complaint with the Occupational Safety and Health Administration . </P> <P> The Clean Water State Revolving Fund (CWSRF) program was authorized by the 1987 WQA . This replaced the municipal construction grants program, which was authorized in the 1972 law under Title II . In the CWSRF, federal funds are provided to the states and Puerto Rico to capitalize their respective revolving funds, which are used to provide financial assistance (loans or grants) to local governments for wastewater treatment, nonpoint source pollution control and estuary protection . </P>

What caused the clean water act of 1972