Sludge at the bottom of wastewater lagoons can lead to all sorts of problems including persistent and heavy annual algae blooms due to high ammonia and phosphorous levels feeding back into the water column from the sludge. It can also lead to BOD5 and TSS permit violations, fecal coliform violations, odor complaints and reduced hydraulic capacity.
The City of Lemoore's Industrial Wastewater Lagoons
To solve these problems modern lagoon system operators now have a choice to remove their sludge chemically while their lagoons stay on line and avoid the odors, the costs, and the hassles of mechanical removal and land application or land filling.
In May 2003 the City of Le Roy, IL, decided to desludge its lagoons using Bio Energizer. Accumulated sludge was taking up valuable lagoon capacity and causing odors. BOD results were also too high. With sludge accumulations in some areas approaching 7 ½ feet, too little water existed over the sludge blanket to maintain odor control.
About 2 mg/l of oxygen should be maintained over a sludge blanket to ensure odor free operations. Sludge blankets will also exert an oxygen demand as they release ammonia, organic acids, and other anaerobically generated by-products.
Ammonia also feeds algae which are a source of BOD as they consume oxygen under dark conditions. When they die they also release their cellular material into the water column feeding other algae and bacteria.
In shallow ponds, accumulated sludge itself can slough off into the effluent which adds to TSS and BOD problems.
After 14 months of treatment with Bio Energizer, about 70% of sludge was removed from the City of Le Roy pond.
The broad-spectrum bio-activator, available from Probiotic Solutions, contains over 29 essential microbial growth-promoting factors. By design, the product is a balanced formulation of vitamins, trace nutrients, enzymes, organic acids, and bio-stimulants that motivate the existing microbial community to greater metabolic capacity and efficiency. Bio Energizer is a not bacterium.
In another case study, the City of Lemoore, CA, wastewater lagoon system was struggling. Along with domestic wastewater, the city also processed industrial wastewater composed of whey, disinfectants, cleaners, and other difficult to digest cheese manufacturing waste. Over a period of years, the sludge blanket reached the surface of the pond.
Concerned about this loss of capacity, Lemoore began looking for ways to remove sludge from pond # 2 where the domestic and industrial wastewater are mixed and treated. Dredging, drying, and removal cost were estimated at about $341 per dry ton. Pond # 2 contained about 3,502 dry tons of sludge which brought estimated removal costs to about $1,194,000.
To keep the lagoon on line, and to save money, the City of Lemoore decided to use Bio Energizer to oxidize the sludge in place. After 2 years, the treatment program removed 1,268 dry tons of domestic and cheese waste sludge, for a savings of $321,388. The lagoons stayed on line and Lemoore personnel simply added the liquid once each day.