Evaluation of the quality indicators of collector-drainage water for reusing purposes: a study from Sirdarya province, Uzbekistan

Currently, in the countries of the Aral Sea basin, due to the negative effects of climate change and the unreasonable use of water resources, the reduction and pollution of existing water resources, the increase in demand for water and its protection are required. Due to the increase in the amount of mineralization due to the discharge of the mineralized collector-drainage waters formed in the irrigated areas to the rivers, their use is limited due to the pollution of the upper and lower streams of the river basins. Researches revealed that the mineralization of Central Mirzachol drainage water has increased by 3.5 times, the total hardness has increased by 4 times, the amount of cation and anion and heavy metals is also high. It was found that the quality of the water of the Central Mirzachol drainage is the worst, and the water of the Boyovut well has a relatively good quality indicator. As a result of the discharge of collector-drainage waters to the Syr Darya River, the main water source of the province, the total hardness of the river reaches 2.0 times, the mineralization is 1.2 times, the amount of cations potassium, sodium, calcium and magnesium, the amount of sulfates and chlorides from anions, heavy metals: manganese, caused the amount of zinc, tin, copper to exceed the permitted standards.