This compact wastewater-treatment system reduces sludge volumes and recovers biogas

The Industrial Technology Research Institute of Taiwan (ITRI, www.itri.org.tw) is conducting a 10-m3/d pilot-plant project to test the performance of its A2O membrane system for municipal wastewater treatment. The project, which is nearing completion, has already supplied important data, including capital cost, running cost and amount of waste sludge produced. ITRI is conducting negotiations with the largest environmental engineering company of Taiwan to market the patented A2O system. Kuan-Foo Chang, a researcher at the Advanced Water Treatment Laboratory at ITRI’s Energy and Environmental Research Labs (EEL), says A2O offers several advantages over conventional systems, including smaller operating space and costs, and 70% reduction in the amount of sludge produced. It also produces methane, which can be used for power generation. The effluent is suitable for industrial reuse. In the A2O system (diagram), pretreated influent enters the system’s multifunction bioreactor. Unlike traditional secondary treatment, which uses aerobic microorganisms, the A2O system uses anaerobic processing. This eliminates the need for a grid tub and sludge tank, and also reduces the amount of sludge produced. After the bioreactor, the…