Wastewater treatment plants or systems remove harmful pollutants from municipal sewers so it is safe to return to the environment. Sewage is pumped into a wastewater treatment plant, screened, aerated, settled, and finally sanitized. The treated water is called effluent and may be discharged into a nearby stream or river, sprayed on land, or infiltrated.
In rural areas, where houses are spaced far apart, homeowners install private septic systems consisting of septic tanks and leach fields. A properly designed, installed, and maintained septic system poses little threat to groundwater supply. However, inadequately functioning and/or failing septic systems can contaminate groundwater with nitrates, harmful bacteria, and/or viruses. Commonly used chemical substances can also contaminate the groundwater when washed down the drain.
As of January 1, 2005, new rules apply to construction of on-site septic and potable water supply systems with a capacity of less than 6500 gallons per day. All new systems are required to get a state permit, issued by DEC’s Regional Offices. Most new systems also will need a local permit until 2007. There are some exceptions for modifications to old systems.
US Geological Survey: A Visit To A Wastewater Treatment Plant - A step-by-step guide describing what happens at each stage of the treatment process and how pollutants are removed to help keep our waterways clean.
US EPA Wastewater Treatment Plant web page
On Site Septic Systems Rules
US EPA Information on Septic Systems
In This Section
Acid Mine Drainage
Bank Erosion & Sediment
Basin Planning
Fisheries
Floodplain Management
Good Road Maintenance
Grants
Invasive Species
Mercury
Non-Point Source Pollution
Organizations
Permits
Riparian Buffer Zones
Wastewater Treatment
Water Quality Studies
Water Supply Protection
Wetlands