بررسي حذف فسفات موجود در پساب صنعتي سنتتيك توسط Acinetobacter calcoaceticus PTCC1318 به روش راكتور ناپيوسته متوالي

Studies on phosphate removal from synthetic industrial wastewater by Acinetobacter calcoaceticus (PTCC 1318) using a SBR system

Surface waters contain certain level of phosphorus. In natural conditions the phosphorus concentration in water is balanced and the accessible mass of this constituent is close to the requirements of the ecological system. When the input of phosphorus to waters is higher than normal, the water pollution will occur. The excess content of phosphorus in receiving waters leads to the extensive plants and algae growth. The phenomenon is called eutrophication and usually decreases the water quality and as a result it may significantly increase the cost of water treatment. Consequently, efforts have been directed toward removing of phosphorus during treatment by microbiological means with a process called enhanced biological phosphorus removal (EBPR), where the removed phosphate from the wasted biomass is converted to the intracellular poly phosphate (poly P). Acinetobacter spp. are of the most important bacteria responsible for EBPR. They accumulate the phosphorus in the forms of poly(P) and poly hydroxy alkanoate (PHA) under aerobic conditions, and use them as the carbon/energy resources to grow in the subsequent aerobic (famine) stage. In this study, a sequencing batch reactor (SBR) operation was used to demonstrate the level of phosphate removal. Each reactor consisted of a vessel and stirrer drive unit, and was operated at temperature about 30°C in 20 h period of time. These values given a mean cell retention time (CRT) of 14 days. The influence of different experimental parameters including pH, agitation speed, sorption time, temperature and initial concentration of phosphate were evaluated. The results obtained by this study showed that this bacterium is capable of decreasing the amount of phosphate from 10 to 12 mg phosphorus per liter to the less than 0.1 mg phosphorus per liter.