January 24, 2012
Upgrades modernize Dryden sewer plant
Bob Ellis/staff photographer
John McGrath, chief operator of the new sewage treatment plant in Dryden, stands above a treatment pool as he explains how it operates during a tour of the facility on Monday.
DRYDEN — The village’s new $7.3 million wastewater treatment plant, discussed and debated for a few years before it became a reality, is running smoothly as it reaches the six-month mark.
The plant, constructed on the site of the old one that became outdated, uses a different process for sewage than its predecessor.
It also can handle 200,000 gallons more per day and produces cleaner water that is pumped into Fall Creek, Plant Operator John McGrath said during a tour Monday.
The plant uses the “aerobic” treatment method, meaning blowers cause air to bubble through tanks of sewage, so the sewage’s solid matter does not settle, causing the sewage to decompose faster and micro-organisms to feed on it more easily. The rest of the process removes nitrogen and phosphorus along with solid matter.
McGrath operates the plant for Yaws Environmental Services of Ithaca, through a contract with the village for $6,500 per month for three years. The previous plant manager, Max Goehner, retired.
The old plant, built in 1967, could no longer handle the volume of sewage from the village’s business and population growth, and broke down repeatedly, to the point where the state Department of Environmental Conservation threatened to fine the village because it violated permit requirements.
The new plant on Wall Street can handle 600,000 gallons of sewage per day. It now averages about 480,000 gallons per day.
Two of the old plant’s five tanks were kept and refabricated to handle the new process. Three other tanks were removed.
The old plant’s one-story building, which goes two stories below-ground, remains with new offices and laboratories constructed onto it.
New buildings and tanks have been finished. Construction began in 2010.
The wastewater treatment plant was the subject of several public hearings as Dryden officials and their consulting engineers decided how to replace the 1960s plant and how to pay for it. They paid for it with a combination of a 38-year loan and a grant from the U.S. Department of Agriculture.
The cost so far has been only $34,200 higher than estimated, still in the $7.3 million range.
Village residents said during hearings in 2009 that they were concerned the new plant would be loud, cause smells and affect water quality in Fall and Virgil creeks.
But there was no smell Monday except in the building where sewage arrives, which smelled a bit like a cat’s litter box.
The five blowers that provide air for the process are so loud inside their room that McGrath and the plant’s other staff member, Nate Service, must wear ear blockers, but they can barely be heard outside it.
The process separates paper products and “grit,” which would be pebbles or coins or anything else solid, from the sewage. That material is dried into chunks and taken to a landfill.
Another process treats the sewage in enormous outdoor tanks, called sequential batch reactors, where micro-organisms feed on it. Air bubbles through it, keeping solid matter from settling the way it does in an anaerobic system, which is what Dryden’s old plant used.
Each tank is 97 1/2 feet long and 33 1/2 feet wide, with water and sewage 13 feet deep, 18 feet below the tank’s edge.
Then the sewage continues to a machine called a belt filter press, which uses metal rolls and a chemical to separate solid waste from water, then dries the solid part into material that looks like black dirt and has no smell.
That material is collected in a large metal bin and taken to Dickson Environmental Services in Bath, Steuben County, where it is mixed with lime and wood chips to create compost.
The water continues to a circular outdoor tank, 35 feet in diameter, where it is treated with chlorine. Then it goes to a rectangular outdoor tank next to that one, 12 feet by 16 feet, where the chlorine is removed. The water, called effluent, then gets pumped along a 3 1/2-mile pipe and into Fall Creek.
The whole series of processes is operated by computer, both inside the blower room where the blower controls are and in McGrath’s office. Screen displays show different parts of the plant operating, and can alert McGrath and Service to problems.
The old plant had to be checked by sight.
McGrath said the belt filter press produces 10 to 15 tons every three weeks of the dried solid matter removed from the sewage.
Village officials said the cost of that is hard to gauge since the past year has been one of transition between the old plant and new plant but is roughly $1,700 to $2,500 per month.
The old process filtered sewage through an 8-foot layer of stone with micro-organisms attached to it.
“We had a few warmup bugs to work out but we’re already at post-construction limits,” McGrath said, meaning the plant is processing its limit of sewage each day about two months earlier than expected.
Village officials expect the plant’s cost to raise sewer and water bills in the next couple of months.
The village of Groton also has an aerobic wastewater treatment system.
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