Increasing problems of eutrophociation and hypoxia in receiving waters in the U.S. (and abroad) is suprring interest in advanced netrient removal, because nutrients spur the growth of phototrophic microorganisms that leads to the two water-quality problems. The two major nutrient pollutants in water are nitrogen (N) and phosphorus (P), and they are present in significant concentrations is sweage and other wastewaters. One of the essential steps to prevent eutrophication and hypoxia is to minimize the discharge of N and P from wastewater treatment facilities will need to achieve greater degrees of removal in the future.The most common means for removing N and P from wastewaters is biological nutrient removal (BNR). Normal practices in BNR today cannot reliably achieve the goals for advanced nutrient removal, which are N and P concentration less than around 1 mg/L of N and P. Of these two, the more challenging goal 9is for P. Biological P removal require that the backteria by cycled between a strictly anaerobic zone (where they release polymerized P) and an aerobic zone (where they store a high amount of P in polymerized form). One problem with all systems used for biological P removal today is that the anaerobic zone receives electron acceptors, making the anaerobic zone less than totally anaerobic. The main acceptor is nitrate recycled from the aerobic zone, but oxygen also enters with the recycle stream and the atmosphere.The hydrogen-based MBfR has been proven for the reduction of nitrate and other oxidized contaminants from waters ans wastewater. In this setting, it is highly effective for removing electron acceptors like nitrate and oxygen. Placing MBfR units in the recycle line, in the anaerobic zone, or both eliminates acceptor intrucsion in the anaerobic zone, thereby making is possible to achieve the goals of advanced nutrient removal in an otherwise typical BNR setting.
|Original language||English (US)|
|State||Published - Aug 4 2005|