Sustainable Algae Based Wastewater Treatment For Small Communities & Decentralized Treatment Applications

Small community and decentralized locations present unique treatment issues that are difficult for many owners and operators to address. In addition to aging installations regulatory limits are becoming more stringent for communities who are now forced to move from traditional solutions such as septic tanks and lagoons to more complex and expensive treatment options. Mechanical plants are proven to meet regulatory limits for small applications but owners and operators are faced with a combination of high maintenance and operational costs, as well as treatment difficulties due to highly variable loads and flows typical of small plant environments. These variable flow patterns and high costs often lead to mechanical failure and operational difficulties in managing plants adequately. In addition, mechanical plants based near communities are socially unacceptable due to appearance, noise, and smell.The use of algal based fixed film technology offers solutions to all of these common problems. The fixed film treatment provides long sludge retention times (SRT) reducing the need for complicated and time consuming management of mixed liquor volatile solids and return activated sludge. Fixed film growth is capable of coping with erratic flows and variable loading rates better than suspended growth while meeting or exceeding treatment outcomes of 10 BOD, 12 TSS and 1 NH3. The algal component of the treatment process leverages photosynthesis to provide oxygen through biological aeration, reducing the need for energy intensive blowers. The Algaewheel system can reduce aeration costs by up to 90% when compared to extended aeration systems. The algae also add stability to the system by consuming carbon dioxide produced by the bacteria and helping to moderate pH fluctuations caused by nitrification.The Cincinnati Nature Center, Summit Lake State Park and Southwestern School District installed Algaewheel systems to replace their aging activated sludge treatment plants. The algaewheel plants have exceeded the treatment capabilities of the original activated sludge plants, while reducing operator hours, energy consumption while becoming an attractive and integrated part of the communities.This study includes data regarding operational and capital expenditures for these algal treatment facilities, as well as performance evaluation results.