Facing new limits on acceptable levels of DBPs in the drinking water, as well as age-old complaints about the taste of the water during the summer algal bloom, the North Texas Municipal Water District turned to ozone disinfection as a possible alternative able to address both concerns.
The state of Minnesota instituted a new water quality requirement that limits cities along the Minnesota River to a 1 mg/L Total Phosphorus limit by 2015 to prevent algae blooms and resulting pollution problems.
The AnoxKaldnes™ MBBR (Moving Bed Biofilm Reactor) process is a biological wastewater treatment process that utilizes specialized plastic carriers to create a surface on which a biofilm can attach.
Clearas Water Recovery's patented treatment platform, Advanced Biological Nutrient Recovery (ABNR) technology, is highly modular and scalable, providing a sustainable approach to cleaning water. The Clearas system consists of three core phases: the blend phase, the nutrients recovery phase and the separation phase. For optimal results, Clearas has partnered with Endress+Hauser for dependable products and reliable technical expertise.
In 2002, Georgia’s City of Flowery Branch faced strict new requirements about discharging water back into nearby Lake Lanier, a community drinking water source, compelling the city to find an alternative wastewater system. After a thorough evaluation of various wastewater treatment solutions, Pall Corporation’s Aria FLEX membrane system was selected due to its critical ability to meet the phosphorus limits.
Petron Bataan Refinery wanted to expand production to process 180 thousand barrels of crude oil per day while changing its feedstock from Arab Light to less costly heavy and sour crudes.
When the Cobb County-Marietta Water Authority (CCMWA) anticipated the need to upgrade the Hugh A. Wyckoff water treatment plant, they turned to granular activated carbon (GAC) technology after vetting several alternatives. The plant, a wholesaler in a two-plant system, processes up to 72 million gallons per day and serves about 350,000 people. Comprising of Wyckoff and the James E. Quarles treatment plant, CCMWA is the second largest water provider in Georgia.
The West Central Conservancy District (WCCD), located in Hendricks County, IN, was formed to resolve sewer issues that the service area was experiencing with the local utilities company in the mid- ’80s.
Lee Wastewater Treatment Facility (WWTF), located in Massachusetts, received an award for its excellent treatment performance in 2012 from the Environmental Protection Agency (EPA), 4 years after start-up.
The Village of Waterbury Wastewater Treatment Plant (WWTP) is located on the Winooski River floodplain, which poses challenges from significant flooding during the spring runoff and storm seasons to strong algal blooms in late spring.
A refinery needed to upgrade the wastewater treatment system to prepare for expected changes brought about by the use of a new crude feedstock with elevated concentrations of TDS and conductivity. Veolia Water Technologies supplied an AnoxKaldnes Moving Bed Biofilm Reactor (MBBR) treatment system to reduce the BOD and ammonia in the effluent.
Facing state Department of Environmental Quality mandates, an Arizona wastewater treatment plant (WWTP) took on a large-scale expansion project and effluent-quality upgrade to become a state-of-the-art water reclamation facility.
About Nutrient Removal
Nutrient removal from wastewater consists of treating wastewater to remove nitrogen and phosphorus before it reenters natural waterways. High levels of nitrogen and phosphorus in wastewater cause eutrophication, a process where excess nutrients stimulate excessive plant growth such as algal blooms and cyanobacteria. The decomposition of the algae by bacteria uses up the oxygen in the water causing other organisms to die. This creates more organic matter for the bacteria to decompose. In addition, some algal blooms can produce toxins that contaminate drinking water supplies.
As authorized by the Clean Water Act, the National Pollutant Discharge Elimination System (NPDES) permit program regulates point sources, such as municipal wastewater treatment plants, that discharge pollutants as effluent into the waters of the United States. In recent years, many of the States’ environmental bodies have lowered nutrient limits to arrest eutrophication. Maryland’s effort to protect the Chesapeake Bay and its tidal tributaries is perhaps the most notable example of nutrient removal in the US. Nutrient removal continues to be a growing area of focus for wastewater treatment throughout the world.
The removal of nitrogen and phosphorus require different nutrient removal processes. To remove nitrogen, the nitrogen is oxidized from ammonia to become nitrate through a process called nitrification. This process is then followed by denitrification where the nitrate is reduced to nitrogen gas which is released to the atmosphere and removed from the wastewater.
Nitrification is a two-step aerobic process which typically takes place in aeration tanks. Denitrification requires anoxic conditions to encourage the appropriate biological conditions to form. The activated sludge process is often used to reduce nitrate to nitrogen gas in anoxic or denitrification tanks.
Phosphorus can be removed biologically using polyphosphate accumulating organisms (PAOs) which accumulate large quantities of phosphorus within their cells and separate it from treated water. Phosphorus removal can also be achieved by chemical removal. Once removed as sludge, phosphorus may be stored in a land fill. However, many municipalities and treatment facilities are looking to resell the biosolids for use in fertilizer.