Biotechnological Approaches for Intensification of Ammonium Removal During Drinking Water Treatment

Abstract

Background. Nitrogen-containing substances are the most common components of groundwater of Ukraine. It was detected, that ammonium may impact on the process of water disinfection, the appearance of nitrite in the distribution system and the problem with the taste and smell of water. The presence of high concentrations of nitrites and nitrates in water can cause methemoglobinemia in children that causes cyanosis and asphyxia. So, there is an urgent demand of developing approaches to intensification of ammonia removing from drinking water. Objective. The aim of these studies is to examine the characteristics of biotechnological processes of nitrogen compounds removing from drinking water in its purification with charge BIOFILTER. Methods. The object of the study was underground water from wells located in the Khmelnitsky region. The initial concentration of ammonia in water was 2.16 mg/dm 3 , nitrite – 0.48 mg/dm 3 , nitrate – 4.5 mg/dm 3 . Investigation of removing of nitrogen-containing substances was conducted on a pilot plant, consisting of aerator, closed contact tank and model filters with charge BIOFILTER. Water was saturated with oxygen in water aerator then came to closed contact tank, where the following parameters were gauged: the concentration of dissolved oxygen, ammonia, nitrites and nitrates. The concentration of dissolved oxygen, ammonia, nitrites and nitrates were controlled in the output water. The pilot plant was set up and worked on the well. Results. It is shown that when the concentration of oxygen decreased from 8.0 to 6.4 mg/dm 3 , a sharp decrease in nitrate concentrations from 4.5 to 3.9 mg/dm 3 was observed. A gradual decrease of nitrates concentrations was observed with increasing doses of consumed oxygen. It was suggested that the nitrification process was passing simultaneously with a process of denitrification as evidenced by a sharp decrease in the concentration of nitrates with a decrease in the oxygen dissolved in water. Conclusions. A decrease in dissolved oxygen concentration violates theoretical ratio of nitrate content in water was experimentally confirmed. The actual content of nitrates in the treated water was less than the theoretical, indicating the passage of denitrification process simultaneously with a process of nitrification. The less concentration of dissolved oxygen in the water at the outlet of the filter, the deeper denitrification is held.