Improving Lake Water Quality

Onondaga County’s Department of Water Environment Protection has upgraded the Syracuse Metropolitan Wastewater Treatment Plant to meet stringent new water quality standards for Onondaga Lake by 2012.

GHD was selected to lead a team of three engineering companies in designing a world class plant based on its track record in the USA. "GHD is recognised as a leader in wastewater technology in the USA and this project has demonstrated why. The company’s work has enabled us to dramatically improve the lake’s water quality," said the Department’s Commissioner Patricia Pastella.

GHD led a pilot project to establish design criteria for a plant which treats 318 megalitres of wastewater a day using biological aerated filters (BAF) and high rate flocculated settling (HRFS) technology to naturally disinfect wastewater and remove ammonia and phosphorus to low levels. A cogeneration system was incorporated to produce electricity and recover heat from gas produced during the separation of biosolids, which are removed and reused as a fertiliser in agriculture.

"We are familiar with US regulatory requirements and after the success of the pilot we worked closely with our partners to bring the plant online - ahead of schedule and below budget, " said GHD Project Director Jerry Hook.

The plant has cut concentrations of ammonia to less than 2.0 mg/L, and phosphorus levels to less than 0.10 mg/L - below the mandatory target of 0.12 mg/L. "To reduce phosphorus concentrations from 0.8 mg/L to less than 0.12 mg/L is a great achievement for us," Ms Pastella said. "We are about two years ahead of the court-ordered schedule, allowing us to improve the lake’s water quality much faster than we had hoped."

The plant is also projected to save USD90,000 a year in energy costs – 40% of the department’s annual budget – and USD45,000 from process and system modifications.