Biological Double-Efficiency Process for Advanced Biological Wastewater Treatment

The Issue 

The activated sludge process is the most common secondary wastewater treatment method for nutrient removal. However, it is energy and space intensive due to the need for separate anoxic and aerobic tanks with secondary clarifiers. This infrastructure demands high capital investment, land, energy, and operation and maintenance costs. Aeration in the activated sludge process is the most energy-intensive and accounts for between 45 percent and 75 percent of the plant’s electricity consumption. With California’s drought intensifying water and energy conservation efforts. The current challenge is to meet the demand from population growth, increasingly strict regulations and aging infrastructure while potentially reducing the energy and water consumption from wastewater treatment plants. 

Project Innovation + Advantages 

The Biological Double Efficiency Process (BDP) is an important breakthrough that combines state of the art/easy to maintain aeration technology, airlift circulation/dilution technology, and an integrated all-in-one bioreactor technology. It utilizes simultaneous nitrification/denitrification principles, leading to significant savings: on average, 50 percent energy, 30 percent capital, 50 percent land footprint, between 30 percent and 50 percent operation and maintenance, and 15 percent water savings. 

BDP’s key innovation for energy savings includes the proprietary aeration technology, short-cut nitrification/denitrification, and the airlift recirculation system. BDP aeration technology reduces 50 percent of the air needed for the secondary treatment process and greatly improves oxygen transfer efficiency to between 48 percent and 52 percent compared to between 20 percent and 30 percent in conventional technologies. Short-cut nitrification/ denitrification was observed in the BDP process that provides substantial energy savings. In addition, the BDP airlift recirculation system reduces energy by using the same blower for aeration and recirculation. The BDP process has an excellent performance record which removes chemical oxygen demand (up to 95 percent), ammonia (99 percent), and total nitrogen (95 percent).