Increasing phosphorus regulations are significantly impacting the bottom line at many WWTPs, often requiring millions of dollars in improvements just to stay in compliance.
One example can be seen in Connecticut, where a state-mandated upgrade to the city’s WWTP to reduce phosphorous levels being released into local waterways has a price tag of $97 million dollars, according to the newstimes.
The project stems from an order from the state Department of Energy and Environmental Protection issued in 2008 that requires that the plant remove 98 percent of the phosphorous from the effluent leaving the plant.
The plant currently filters out 90 percent. Improving on that is a tall order, said David Day, public utilities superintendent for Danbury, one of the five communities serviced by the plant.
“We’re treating down to very stringent limits,” he said in the newstimes article. “To get to that percentage the plant will have to build new filters and introduce a new technology. The type of new technology the plant will choose is still being discussed.”
The plant services the communities of Danbury, Bethel, Brookfield, Newtown, and Ridgefield. Each community will contribute to the cost of the project with a low-interest loan determined based on usage. Danbury’s share will be $52.2 million, Bethel’s share $8.8 million, Brookfield’s $2.2 million, Ridgefield’s $820,000 and Newtown’s $646,000. The remaining cost will be covered by the state, due to a General Assembly bill recently passed that lets the state cover 50 percent of the costs on these type of projects.
The plant has to meet some of the strictest phosphorus standards in the state because it is in a basin that already has large phosphorus loads. Another challenge comes because it is a large plant that empties into a small stream, Limekiln Brook, which feeds into the Still River, before going into the Housatonic River and then Lake Lillinonah.
The city initially fought the order to reduce the phosphorous because they didn’t think the overhaul would have a big impact on the environment, said Mayor Mark Boughton. He said the city still disagrees with the order, but will take the steps to meet it.
“Our scientists and engineers don’t believe it will make the impact the state thinks it will,” he said, according to the newstimes.