Baltimore has approved a $7.3 million contract to Bio Gro Systems Inc. of Annapolis to remove an estimated 170,000 tons of sludge from the Back River Waste Water Treatment Plant in the next two years.
The contract, approved yesterday by the Board of Estimates, involves a new process that would dispose of sludge through a more efficient, economical and odor-free method, said George G. Balog, the city public works director.
Balog said the city is negotiating with potential contractors to build two facilities at the city's Back River plant in eastern Baltimore County.
They would use a heat-drying process that changes wet sludge into dry pellets. Sludge would be piped into the heat-drying facilities. The pelletswould be shipped out and used for agricultural application, Balog said.
"We would no longer be at the mercy of the weather and it would save the city money in the long run because we wouldn't have to resort to emergency sludge-hauling contracts," Balog said.
The contract would bring an end to a malodorous three years in which the city had problems disposing of its sludge.
In the past two years, especially, sludge deposits backed up at Back River because prolonged rainy weather made it impossible to dry the smelly material sufficiently to haul it away for such uses as topping for landfills. Complaints from residents of the nearby communities forced the city to declare an emergency and award non-bid contracts to get rid of the sludge.
"We've been paying on average $50 a ton to get rid of the sludge on an emergency basis," Balog said. Bio Gro's contract is for $43 a ton.
There is no sludge in storage at Back River, Balog said, "as opposed to this time last year, when we had about 80,000 tons in outside storage. We've been able to remove it as soon as it is produced."
Balog said new Environmental Protection Administration requirements meant the city had to improve on the percentage of pollutant materials removed from waste water that was discharged into Back River and ultimately Chesapeake Bay.
"We went from removing 80 percent of the pollutants in 1969 to 95 percent three or four years ago, but the more efficient the operation the more sludge. . . " Balog said.
Back River nearly doubled the sludge generated from 350 tons a day to the current 650 tons.
Bio Gro would be guaranteed half of the contract. Business could go to other firms that were not big enough to bid on the entire contract, but submitted non-contract proposals for the other half at lower rates than Bio Gro. But, if these smaller firms can't come up with the state-approved permits to dump the sludge, Bio Gro would assume the full two-year contract.