Экобиотехнология обработки иловых осадков: удаление соединений фосфора

Abstract

This paper focuses on the study the problems of removing phosphate from wastewater and sewage sludge. An experimental study of the phosphorus removal during anaerobic microbial degradation (AMD) under sulfidogenic condition of sewage sludge was carried out. The analyzes of materials structure was performed on the automated DRON-4-07 was shown that among the major mineral components of the final product of the biosulfidogenic treatment are: quartz, potassium hydroxide and potassium hydrogen phosphate dihydrate, brushite, phosphorus oxide, calcite, ammonium sulfate. Much of phosphate ions were liberated into the liquid phase with removal from wastewater. Sulfidogenic sludge with acetatotrophic microorganisms domination was formed in the process of AMD. The phosphate ions were released from the microbial cells due to active diffusion of volatile fatty acid under bio-sulfidogenesis. Thus, polyphosphates (HPO3)n were released from the cells in the liquid phase. Reduction reaction of phosphate metals hydroxide such as Fe(НО)y(РО4)x has occurred under anaerobic conditions with phosphate ion release to liquid phase. Thus, we can noted several positions: the pre-denitrification sludge with a partial flow of wastewater is improves of anaerobiosis conditions in anaerobic bioreactor (tank); the phosphate removal from sewage sludge intensified when phosphogypsum input to anaerobic tank for promotion the process of sulfate reduction with deposition of heavy metals to sulfide form; the removal of phosphate ions from the liquid phase is advantageously carried out in a separate purification unit via precipitation reagent. The main mechanisms of phosphorus removal were determined. The biochemical model of sewage sludge treatment with phosphorus transformation under sulfidogenic condition was formed. The technological applications efficiency of such system was developed. The first stage of the process is denitrification occurs in the biounit, which receives sludge from the partial flow of wastewater. The second stage is the anaerobic microbial degradation under sulfidogenesis. The third stage is phase separation in the settling process. The solid phase from the decanter is output from the system, the liquid phase is sent to the phosphorus removal unit (fourth stage). Phosphate ions can be precipitated from the liquid phase of sludge by various reagents with subsequent using as a fertilizer in agriculture. Keywords : anaerobic microbial degradation, sulfidogenesis, sewage sludge, phosphorus compounds.