Failure of the side-stream deammonification process. Risk of violation of the WWTP effluent quality

Abstract

Stable and efficient nitrogen removal is one of main goals of wastewater treatment. Applying deammonification, beyond many advantages, results in the risk of the WWTP effluent quality violation in case of the failure of the process. Then nitrogen load to activated sludge is increasing rapidly which could therefore lead to quality violation in activated sludge effluent. Simulation studies have been presented on the effect of deammonification failure on nitrogen removal performance in the case of a typical, medium sized WWTP (ca. 115 000 PE). The studies were based on the calibrated ASM1 model of real WWTP and a fictional scenario of implementing deammonification and subsequent failure. Implementing deammonification enables SRT optimization of the sludge retention time (SRT) in its main line thanks to lower nitrogen load. Two scenarios have been shown, considering or not optimization of the SRT in WWTP. The results show that SRT optimization leads to decrease in nitrifier mass and raises difficult issues in appropriate nitrogen concentration in the effluent.

Combining numerical simulation with response surface modelling for optimization of reject water partial nitritation/anammox in moving bed biofilm reactor

“…Mao et al [4] emphasize properly that 'for the strict process control of a one-stage (partial nitritation/ anammox) system, operational parameters and operational conditions of a one-stage system will be the key concern in the future'. Janiak et al [5] pointed to the risk of declining the mainstream effluent quality as the effect of the breakdown of reject water deammonification system. Optimization of the PN/A systems seems to become even more important due to the implementation of the advanced processes of anaerobic digestion (AD) of sewage sludge like, for example, integration of thermal hydrolysis process and AD, which is connected with a major increase in ammonium-nitrogen concentration in the reject waterup to 3000 mgN/l [6].…”