Piloting Program to Optimize Design and Operation of Innovative MBBR Treatment Strategy

A moving bed bioreactor (MBBR) pilot study was carried out to optimize design criteria and to evaluate four treatment strategies to design and operate the MBBR process to suppress nitrification while maintaining reliable carbonaceous BOD (CBOD) removal. The treatment objectives were to reliably control effluent NOx-N and soluble CBOD to less than 10 mg/L. The treatment strategies included: adjusting media loading rates, DO control, step-feeding of the process, and providing an internal recycle back to a switching (oxic/anoxic) zone to provide moderate nitrate removal if necessary. The pilot program results validated that the MBBR process could be designed and operated to accomplish reliable CBOD removal while adequately suppressing nitrification to consistently have an effluent nitrate concentration of less than 10 mg/L. The results were used to calibrate the GPS-X process simulation model to be used in design and to predict process performance under current and future loading conditions.