Influence of Aeration on the Composition of Biocenosis and Efficiency of Removal of Nitrogen-Containing Compounds on Rapid Filters for Drinking Water Treatment

Abstract

Background . Nitrogen compounds are the most common components of groundwater in Ukraine. Nitrates for humans are not poisonous, but in the human body, they turn into nitrites, affecting the health of the whole organism. One of the possible ways to reduce the content of nitrogen compounds is the use of biotechnological treatment methods, which are not yet widely used in water treatment plants in Ukraine. Objective . The aim of the paper is to study the influence of oxygen on the biocenosis of rapid filters for the drinking water treatment and the efficiency of removing nitrogen-containing compounds. Methods . To assess the influence of aeration on the biocenosis of rapid filters for drinking water treatment, the total microbial number in the upper and lower parts of the filter was measured at different doses of oxygen that was fed to the filter. Results. The experiments show that depending on the different concentration of dissolved oxygen on rapid filters for drinking water treatment, the simultaneous passage of nitrification and denitrification is possible. It is established that with an increase in oxygen concentration up to 7 mg/dm 3 , the intensity of ammonium removal doesn’t increase, but the value of the CFU in the lower part of the filter decreases (up to 3000 CFU/cm 3 ). The concentration of oxygen in the aerator for ammonia removal is 7 mg/dm 3 (ammonium concentration in water after filtration is 0.11 mg/dm 3 ); nitrites – 7.5 mg/dm 3 (0.27 mg/dm 3 nitrites in water after filtration); nitrates – 5.5 mg/dm 3 (2.4 mg/dm 3 of nitrates in water after filtration). Conclusions. It is determined that under conditions of rapid filters, nitrification predominantly occurs in the upper part of the filter, and denitrification in the lower part. The optimum concentration of oxygen fed to the filter was established for the simultaneous passage of nitrification and denitrification, and the effective removal of nitrogen compounds in the preparation of drinking water. The concentration should be 5.5 mg/dm 3 .