Startup strategy for nitrogen removal via nitrite in a BAF system

Abstract

A biological aerated filter (BAF) pilot plant consisting in two reactors (aerobic and anoxic one) was used to determine a strategy to remove nitrogen via nitrite. RNA/DNA analysis was performed to assess microbial activity and support chemical results. In less than 13 days the pilot plant was able to remove COD and suspended solids. Nitrogen removal via nitrite pathway could not be observed until day 130 th when the empty bed contact time (EBCT) was set at 0.71h. Nitrite was detected in the aerated BAF effluent but never nitrate. qPCR of amoA gene from RNA and DNA extracts of the aerobic biofilm confirmed that ammonia oxidizing bacteria (AOB) were present from the beginning of the operation but not active. AOB activity increased by time reaching stability from operational day 124 th. The combination of both, low EBCT together with high OLR, has been demonstrated to be a feasible strategy to startup a BAF to achieve nitrogen removal via nitrite.

Advanced Treatment of Digested Restaurant Wastewater Using a Combination of Anaerobic/OxicUnit, Fenton, and a Biological Aerated Filter in Pilot-Scale Treatment

“…A large amount of kitchen wastewater is generated after solid-liquid separation and the removal of high chemical oxygen demand Digested restaurant wastewater contains high concentrations of organic matter, nitrogen, and phosphorus, which can be easily degraded by microorganisms. Hence, biological nitrogen-and phosphorus-removal processes, such as anaerobic/oxic (A/O) and biological aerated lter (BAF), are the most simple and effective methods to treat digested restaurant wastewater Gabarró et al 2019;Gao et al 2017). Such processes have the advantages of low operational costs, low susceptibility to sludge lamentous expansion, strong resistance to shock loading, and ease of automation and management.…”