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Minnesota <br />Pollution <br />Control <br />Agency <br />wq-wwists 1 -1 0 <br />Why Treat Sewage? <br />Facts About Subsurface Sewage Treatment <br />Systems <br />Wastewater/Individual Sewage Treatment Systems #1.10 • June 2008 <br />ntroduction <br />What is sewage and why treat it? <br />Although the answers may seem <br />obvious, these questions are often asked. <br />Sewage is wastewater from domestic <br />activities such as cooking, cleaning, <br />laundry or bathing. Exposure to sewage <br />through ingestion or bodily contact can <br />result in disease, severe illness, and in <br />some instances death from the bacteria, <br />viruses and parasites contained in the <br />waste. Therefore, it is important for sewage <br />to be properly treated. <br />Few people disagree with the need to treat <br />sewage generated by large municipal or <br />industrial sources, and regulations <br />governing these larger facilities have been <br />in place at the state and federal level for <br />decades. However, the regulations <br />governing sewage treatment systems <br />serving homes and mid-sized facilities are <br />much more recent. These systems are <br />called Subsurface Sewage Treatment <br />Systems (SSTS), commonly referred to as <br />septic systems. SSTS were formerly known <br />as Individual Sewage Treatment Systems <br />(ISTS). <br />While the terminology has changed to <br />reflect changes in the septic system <br />industry, a septic system is still a <br />combination of tanks or other treatment <br />devices providing initial treatment of <br />sewage which ultimately discharging the <br />sewage into the soil for fmal treatment. <br />And, just as with large wastewater <br />facilities, SSTS need to be properly <br />designed, installed, regulated, and <br />maintained. <br />Regulatory background <br />In 1968, the Minnesota Shoreland Act was <br />passed. It contained provisions for septic <br />systems to be evaluated and managed <br />properly within shoreland areas to better <br />control their impact on water quality, and <br />resulted in distinct improvements in water <br />quality. <br />In 1994, the first state law specifically <br />addressing septic systems was enacted. <br />This legislation, known as the ISTS Act <br />and codified as Minn. Stat. §§ 115.55 and <br />115.56, requires all new construction and <br />replacement septic systems to meet <br />minimum statewide standards. It also put in <br />place a system to upgrade failing existing <br />SSTS before construction of an additional <br />bedroom, and methods to replace failing <br />SSTS within certain time frames depending <br />MI their level of failure. <br />The 1994 act has been amended in recent <br />years, with major changes in 1996 and <br />again in 2008. As SSTS are intended <br />provide long-term, reliable, high quality <br />treatment and disposal of the sewage <br />generated in a home, regulations will <br />continue to be amended as the SSTS <br />industry advances. <br />Public health reasons <br />While the 1994 act helped to ensure newly <br />constructed or replaced septic systems will <br />adequately treat sewage, many of the more <br />than 500,000 septic systems in use in <br />Minnesota were installed prior to the law <br />revisions and therefore, may not be <br />adequately treating sewage. <br />Minnesota Pollution Control Agency • 520 Lafayette Rd. N., St. Paul, MN 55155-4194 • www.pca.state.mn.us <br />651-296-6300 • 800-657-3864 • TTY 651-282-5332 or 800-657-3864 • Available in alternative formats <br />