Testing of Novel Denitratation/Deammonification Process for Mainstream Total Nitrogen Removal

Stringent nutrient discharge limits require utilities to employ energy and chemical intensive biological nutrient removal (BNR) processes. Treatment of ammonia rich centrate loads generated from dewatered digested sludge has become an economical counterpart to Mainstream BNR. This novel Partial Denitratation/Deammonification (PDNA) process was previously developed and conceived under the NYC DEP Applied Nitrogen Research Program to effectively carry out separate centrate treatment (SCT). Following this effort, the novel denitratation/deammonification process was evaluated for use in Mainstream BNR. The primary driver for developing this process was to reduce O and M costs associated with the traditional nitrification/denitrification process (e.g. aeration energy and supplemental carbon) and to develop a deammonification process that was robust, flexible and relatively easy to operate. Standard nitritation/deammonification processes have proven to be challenging to effectively implement in mainstream process due to difficulty in suppressing nitrite oxidizing bacteria (NOB) growth and maintaining a high enough selection pressure for ammonia oxidizing bacteria (AOBs) due to relatively low and variable ammonia loads in primary effluent. This study demonstrated that the application of glycerol driven partial denitratation/deammonification to treat primary effluent results in several nitrogen removal pathways being used to achieve TN removals up to 85% while utilizing 75% less carbon and 50% less aeration for varying ammonia loads.