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.
Several years ago, the Environmental Protection Agency (EPA) began an initiative in the Mississippi River basin to control excess amounts of nitrogen and phosphorus pollution entering the Gulf of Mexico through watersheds and point sources such as municipal wastewater treatment plants.
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.
The Town of Elkton, Maryland, located in Cecil County near the head of the Chesapeake Bay, has a population of approximately 15,000 and an average elevation of 9.1 m (30 ft). Elkton is an economically strong, stable community that is very conscientious about environmental issues. In an effort to protect the Chesapeake Bay aquatic life, new stringent wastewater effluent regulations were implemented requiring very low nutrient levels in wastewater treatment plant discharge.
Since water is an essential element in food or beverage operations, reusing it can reduce a business’s water usage ratios, help meet sustainability goals, lower supply risk and contribute to cost savings, making it a top priority for many companies today.
In late 2013, Headworks Bio Inc. was awarded a contract with General Contractor Soluciones Tecnicas Ambientales, S.A. (SOLAMSA) to supply an IFAS system to upgrade the existing Ptar El Roble conventional activated sludge (CAS) treatment facility in Puntarenas, Costa Rica — the first IFAS installation in the country.
Sturbridge, Massachusetts historically suffered from periodic blooms of filamentous bacteria that caused bulking in the secondary clarifiers of their three activated sludge package plants.
Prior to 2007, Concord, Massachusetts wastewater treatment plant operated under a NPDES permit that allowed a seasonal phosphorus limit of 0.7 mg/L. But with the issuance of a new five-year permit with a phosphorus limit of 0.2 mg/L and the probability that future limits could reach as low as 0.05 mg/L, Concord needed a treatment solution that would be reliable and cost-effective today and over the long term.
With the AnoxKaldnes Hybas IFAS system, the City of Cocoa Beach, FL, met the challenges of tighter nutrient regulations, site constraints, and operating conditions. And the project met the city’s goals to meet these challenges with a simultaneous decrease in energy use. On top of that, the city did not need to increase operations time or staffing to meet these goals. With the AnoxKaldnes Hybas IFAS system, the city is now meeting stricter nutrient regulations – and doing it sustainably.
In 2008, AnoxKaldnes Hybas™ designs were completed by Veolia for the upgrade of the Field’s Point Wastewater Treatment Facility to meet new seasonal effluent limits for TN and TIN.
The city of Davisboro is located in Washington County, Georgia. The 2012 census population was 1,793 at the 2013 census. The population includes Washington State Prison, approximately 1,500 prisoners.
Economic development has its price and sometimes calls for major upgrades to a community’s wastewater treatment facilities.
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.