Bio-Conversion of Accumulated Sludge with Bacterial Augmentation Process in Aerated Lagoons for Municipal Wastewater Treatment

The objective of this study is to determine the feasibility of using a bacterial augmentation process with a bacterial culture product (LLMO) addition in the bio-oxidation of accumulated sludges in the aerated lagoons in municipal wastewater treatment plant. Mauldin Road Wastewater Treatment Plant, Greenville, South Carolina, of Western Carolina Regional Sewer Authority was selected in this field investigation. LLMO was added to the influent to the roughing filter at a dosage of 1 mg/1 to enhance the bio-conversion of settled sludge in the aerated lagoons. Sludge profile measurements in aerated lagoons were taken prior to and after the LLMO addition to the treatment plant. The LLMO contains seven strains of bacteria, including Bacillus, Pseudomonas, Nitrosomonas, Nitrobacter, Cellulomonas, Aerobacter and Rhodopseudomonas, which are commonly found in soils and wastewater treatment plants. The aerated lagoons had an accumulated sludge of 6.7 million pounds prior to the study period. During the eight-month study period with LLMO application, 5.03 million pounds of sludge was removed by the bio-oxidation process. This is equivalent to a removal of 18,600 lbs solid/day or 20,000 to 30,000 lbs BOD/day from the accumulated sludge in the aerated lagoons. During the study period of sludge removal by bio-conversion, there was no deterioration in final effluent quality in terms of BOD or TSS or other pollution parameters. The sludge blanket depth was reduced from 7–8 feet to 2–3 feet. Other benefits observed during period of LLMO addition include energy saving and odor control. It is concluded that bacterial augmentation with LLMO addition enhanced bio-conversion of accumulated sludge in the aerated lagoons without deterioration in the final effluent quality. © 1986, Taylor & Francis Group, LLC. All rights reserved.