Wastewater Treatment Plants

Wastewater treatment plants remove contaminants from wastewater generated by water runoff and from household and commercial sewage. Runoff generally refers to rainfall that may pick up sediment, metals, organic compounds, animal wastes, oil and grease as it travels across the ground. There are still some open sewers that dump runoff into a river or stream, but more and more are being converted to closed sewers that are collected at a treatment plant.

Sewage – waste from toilets, baths, showers, kitchens and sinks – is created by residents, institutions and businesses. Wastewater is 80 percent soapy water from showers, dishwashers and laundry and only 20 percent by volume from toilets.

Wastewater treatment generally involves three stages: primary, secondary and tertiary treatment. Primary treatment consists of holding sewage in a basin where heavy solids settle to the bottom as oil, grease and lighter solids float to the surface. The settled and floating materials are removed and the remaining liquid can be discharged or subjected to secondary treatment. Secondary treatment removes dissolved and suspended biological matter, typically through the use of indigenous, water-borne micro-organisms in a managed habitat. Tertiary treatment refers to any treatment after the secondary phase. Treated wastewater can be discharged into bodies of water or used for irrigation, or it can be used for groundwater recharge or agricultural purposes. Most of today’s tertiary treated water is cleaner than the stream or river into which it is discharged.

AMERICAN ductile iron pipe is a long-established choice for wastewater treatment plants. Its wide selection of joints and fittings can be fabricated for any application, including buried and exposed. In particular, the additional joint deflection offered by AMERICAN’s exclusive boltless Flex-Ring joint is ideal for pipe and valve installations in and around structures and loaded tanks. AMERICAN provides a range of linings and coatings designed for different situations. In addition, AMERICAN’s line of valves and spiral-welded steel pipe make the company a premier manufacturer of wastewater treatment plant products.

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