Ecological and economic justification of water resources protection efficiency based on the drainage and waste water recycling
The purpose is the development of a mathematical apparatus that makes it possible to calculate both the amount of possible increase in the irrigated area due to the recycling of drainage and waste water, and the amount of natural water savings provided that the irrigation area remains unchanged, as well as determining the possible annual additional profit from the recycling of drainage and waste water on irrigation systems. Materials and methods. The systematic analysis and, as a result, a balance method, the key factor of which is the observance of the annual soil salt balance during irrigation are used, together with various options for recycling drainage and waste water. Results. To achieve the research goal, the following was carried out: modeling the determination of the maximum allowable salinity of drainage and waste water suitable for irrigation; modeling of drainage and waste water recycling without dilution and with their successive dilution; modeling of drainage and waste waters recycling. As a result of the studies carried out for the option of drainage and waste water recycling with their successive dilution, the possibility of obtaining an annual additional profit from the recycling of such water in irrigation systems under conditions of insufficient water supply, which will be about 18 %, is revealed; the payback period for modernization of the irrigation system will be about 6 years. Conclusion. Recycling of drainage and waste water during irrigation is a promising direction for increasing water supply and improving the efficiency of water resources protection. With the help of the ratios obtained, the issues of optimal water distribution between irrigated plots and determination of their areas can be solved, taking into account the availability of natural waters and drainage and waste water recycling.