Investigation into organic matter and nutrient removal in an activated sludge wastewater treatment system: case study of Bojnurd

Lack of efficient wastewater management and letting out untreated sewage into the environment demonstrates the need for efficient wastewater management to prevent harmful effects for health and environment. Hence, efficient wastewater management is one of the most important environmental issues. It is not possible to evaluate efficiency of treatment system without perception of efficiency of the system. In this study performance of wastewater treatment plant of Bojnurd was evaluated and surveyed. This is a descriptive sectional study. Efficiency of activated sludge treatment system in removal of organic matter and nutrients was assessed. For this purpose samples were taken twice a month from two areas of the system during 6 months and the amount of removed organic matter and nutrients was measured by COD, BOD, Nitrate, Nitrite and total phosphorus test. Then the results were analyzed by statistical analysis. Average concentration of COD in inlet and outlet was 503 and 177.35 mg/L respectively and BOD was 58.29 and 28.82 respectively. For nutrients average amount of nitrate in inlet and outlet was 22.67 and 7.47respectively and this amount was 0.209 and 0.15, and 22.28 and 11.45 for nitrite and total phosphorous respectively. According to the results, treatment plant of Bojnurd due to the appropriate atmospheric condition and proper design rate of organic matter and nutrient reduction reduce the pollution and is suitable to meet the standards.