Abstract
The study presents data on changes in the chemical composition of sludge in Astana (Republic of Kazakhstan) during composting with the addition of wheat straw and microbial biological preparations.The purpose of this study was to evaluate the agronomic value of sludge compost as a fertilizer.The specific hypotheses tested in this study were: (1) the addition of different biological preparations will improve the quality of the compost, enhancing its nutrient content (nitrogen, phosphorus, potassium), and (2) the incorporation of wheat straw will reduce nitrogen losses during composting by increasing the carbon-to-nitrogen ratio.Quantitative changes in the chemical components of compost from a mixture of sludge and wheat straw during composting were studied.The pH of the sludge increased during the first 10 days of composting and then decreased.In almost all samples, the amount of total phosphorus and potassium increased up to 2 times during composting.Losses reached up to 35% of the initial nitrogen, as a result of nitrogen volatilization.The addition of straw helped to reduce nitrogen losses during the active phase by increasing the carbon-to-nitrogen ratio in the initial mixtures.