Radionov M. Nitrification as an ecological factor of interaction of water reservoirs and related to them water use facilities

The relevance of work is determined by providing the level of ecological safety of potable water in time of nitrification microflora influence from natural water reservoirs connected with water preparation stations (sources of water supply) and necessity of providing the ecological safety for natural water reservoirs which accept the waste water discharge from waste water treatment plants. Nitrification in natural water reservoirs defines self-purification process from nitrogen compounds. From the activity of nitrification process in stations of water preparation depends potable water safety from the contamination of nitrogen compounds. Nitrite concentration control had shown that water preparation conditions provide such rate of the 2 nd nitrification stage, which reduces nitrite concentration to ecologically safe concentrations. According to observation of the data of 8 year period was established that there is a positive correlation between the nitrification index in natural water reservoir and in water preparation stations. As biochemical investigations had shown, water with high concentration of N–NH4 (during preammination process) activates the development of ammonia oxidation bacteria, which causes raising of N–NO2 concentration to invalid values. During the method of postammination the concentration of nitrifying bacteria of the 1 st stage of nitrification in filter backfill decreases a 150 times. The analisation of nitrification index data in water preparation station «Donets» strongly prove that nitrification in natural water reservoir is significant ecological factor of influence on microbiological processes, which occurring in water preparation stations, and consequently on an ecological safety of potable water for population. Ammonia nitrogen concentration in treated waste waters after the biological treatment significantly decreases (up to 92%). While nitrite and nitrate concentrations increasing, which is an obviously indication of passing both stages of nitrification (I and II phase). Specific rate of N–NH4 oxidation by activate sludge microbiothenoses is much higher, compared with bottom sediments. Activate sludge nitrifying ability of waste water treatment plants aeration tanks was determined by biochemical method according to hydroxylamine oxidoreductase enzyme activity and by microbiological method – concentration of nitrifying bacteria of the 1 st stage. Nitrifying ability of activate sludge from the aeration tanks is 10 times higher then nitrifying ability of bottom sediments of riv. Siv. Donets and Krasnopavlivske reservoir. Considering the concentration of suspended matter shows that everyday emission of nitrifying bacteria from waste water treatment plant into the riv. Udy can reach 2,7 * 10 17cell/day. Waste waters which was treated on waste water treatment plant №2 of Kharkiv city directed into the discharge canal and then through the collector discharging into the riv. Udy, which is a tributary of riv. Siv. Donets. Determination of nitrification processes activity in riv. Udy in the area 500 meters before and 500 meters after the treated waste waters discharge was made by using three directions: investigation and calculation of nitrification activity in riv. Udy based on multiyear data, experimental determination of nitrifying activity in water, experimental determination of nitrifying activity in bottom sediments. Analyses of water from riv. Udy in the area 500 meters before and 500 meters after the treated waste waters discharge had shown that concentration of ammonium nitrogen during 5 year study basically decreases, while concentration of nitrites and nitrates constantly increase, which is an evidence that nitrifying activity in riv. Udy enhances in the area after the discharge. This conclusion is proved by the calculation of nitrification index for the investigation period. According to experiment data for areas before and after the discharge, chemical constant of the 2 nd stage of nitrification was higher then the constant of 1 st stage. According to experimental results we can assume that after the discharge microbial contents of nitrifying microbiocenothes changes due to incoming microflora from the waste water treatment plant. Experimental investigation of nitrifying ability of bottom sediments from riv. Udy before and after the discharge had shown that hydroxylamine oxidoreductase activity in bottom sediments before and after the discharge has the same order of values. As follows, nitrifying activity in riv. Udy increasing, which was revealed according to multiyear data of control of nitrogen compounds, pH, nitrification index in the area of 500 meters before and 500 meters after the treated waste waters discharge is due to intensification influence of the waste waters discharge. Obtained results show that nitrification in biological waste water treatment plants is an essential ecological factor in natural water reservoir.