The efficiency of nitrogen removal in synthetic laundry wastewater using a submerged membrane bioreactor at different total nitrogen volume loadings and MLSS concentrations

Abstract

The aim of this study was to determine the effect of various total nitrogen volume loadings and various mixed liquor suspended solids (MLSS) concentrations in the submerged membrane bioreactor on the nitrification and the efficiency of nitrogen removal from soft synthetic wastewater. In the first part of the research the total nitrogen volume loading was increased from 0.063 to 0.315 gL-1d-1. The activated sludge was not removed from the reactor and therefore the concentration increased from the initial 4 gL-1 to a maximum value of 25.6 gL-1. The results for removal of total nitrogen showed that the treatment effect was highest at the total nitrogen volume loading of 0.19 gL-1d-1, with 84 % removal efficiency. In the second part of the research the total nitrogen volume loading was held constant at 0.19 gL-1d-1 and the MLSS concentrations were varied between 10 and 15 gL-1. The results in this part of the research showed that nitrification did not occur when the activated sludge concentration was 10 gL-1 and that nitrification started when the activated sludge concentration increased. The research shows the connection between biomass concentration and nitrification degree in the MBR.