SHARON in New York, U.S.A.
The advantages of Nitrogen Removal
Grontmij, who is the owner of the proprietary SHARON technology, is responsible for design, commissioning and process start-up. New York City has developed a Comprehensive Nitrogen Management Plan to reduce the aggregate effluent nitrogen loading from Water Pollution Control Plants (WPCPs) to the Upper East River and Jamaica Bay. Separate centrate treatment has been identified as an integral part of this plan, since up to 40% of nitrogen loading at WPCPs with centralized dewatering facilities is directly attributable to centrate loading.
Pilot research by the New York City Department of Environmental Protection related to nitrogen removal and other related operational issues, showed SHARON to demonstrate significant potential as a highly efficient, cost effective and environmentally sound process for the removal of high levels of nitrogen from centrate.
The SHARON Process
SHARON is high active process for N-removal operating without sludge retention. Due to differences in growth rate nitrite oxidisers are washed out of the system while ammonia oxidisers can be maintained, resulting in N-removal over nitrite instead of nitrate.
N-removal with SHARON via nitrite has several advantages:
- oxidation to nitrite saves 25% on aeration energy;
- denitrification of nitrite saves 40% on BOD addition;
- denitrification of nitrite at high temperatures reduces sludge production by 50%;
- simple process with high process stability.
New York City considers it prudent to evaluate this innovative, yet proven, technology at demonstration scale to determine its applicability as part of the long term nitrogen reduction plan for New York City and to verify the potential cost savings as a result of implementation of this process.
Under the Management Plan, New York City is currently building a demonstration plant for the SHARON system at Wards Island WPCP. This SHARON will treat centrate produced at the plant in the sludge dewatering facility. This facility dewaters anaerobically digested sludge produced at Wards Island and at two other WPCPs.
The SHARON for Wards Island WPCP, with a capacity of 5.000 kg NH3-N per day, will be operational in 2009.