Grease Buildup in Low-flow Lift Stations

Aug. 2, 2002
BI-CHEM® DC 2000GL with BioS? 3112 Grease Reduction Evaluation In Low-flow Lift Stations Buildup of fats, oils and greases (FOG) in lift stations has negative impacts on wastewater collection systems. Most system blockages can be traced to FOG which, at its worst, causes sewage spills, manhole overflows, sewage backups in homes and businesses, odor complaints and pump failures. Consequently, accumulated FOG must be cleaned out on a regular basis and disposed of properly. While bioaugmentation (the addition of live microbes) has been successfully used in the past to treat buildup in collection systems, it generally has had its lowest success rate in smaller stations, with flows of less than 50,000 gpd (190 m3/day). The objective of this study was to determine the effect of BioS? 3112 on FOG accumulations in small stations. BI-CHEM® 2000GL is specifically designed for collection system use and BioS? 3112 is a newly discovered, patent-pending spore forming bacterium that is especially effective in degrading long-chain fatty acids which make up the major fraction of most grease deposits. The treatment for each lift station during the field study included a weekly dosage of 2 pounds of DC 2000GL modified with BioS? 3112 in SoluPak. The average flow for both pump stations in this field study was less than 24,000 gpd (91 m3/day). Figures 1- 6 document the results for both lift stations. Figure 4 presents the main components of one of the bioaugmented lift stations. Performance in this study is documented over 26 weeks at Pump Station 1, and 15 weeks at Pump Station 2. A progressive reduction in grease was observed in both lift stations as evidenced by the changes in color and consistency of the grease deposits. The color and consistency of the grease in both stations changed from thick, dark and crusted grease deposits covering between 70 and 80% of the pump station surface areas to thinner, tan deposits of grease covering less than 20% of the pump station surface areas. Thus, field results demonstrate that the addition of BI-CHEM® DC 2000GL with BioS? 3112 resulted in significant reductions in grease in two small lift stations over 4-5 month monitoring periods. Following annually scheduled maintenance at one of the stations, continued product use prevented buildup through the end of the monitoring program three months later, thereby reducing or eliminating the frequency of the cleaning required to keep the station functioning.