Performance of temperature changes and dosage for enhancement of nitrogen and phosphorus removal from wastewater: A comparative study

Abstract

Abstract The development in Iraq, in addition to the increase in the population and the increase in the standard of living, has led to a marked increase in the demand for water, as the shortage of fresh water resources has become a problem that concerns specialists and decision-makers as it affects the water deficit, especially in the provision of drinking water (the basis of life) in addition to other requirements such as agriculture. Which led to the search for other possible solutions available. One of these solutions is the reuse of treated wastewater in agriculture or any other uses to save fresh water and expand agricultural areas after removing high concentrations of nutrients such as nitrogen and phosphorous. The aim of the study is to improve the performance of the treatment method used by the sewage treatment plant to achieve the removal of nutrients from the treated water. The dual use of a biological treatment and chemical precipitation process to remove phosphorous compounds from wastewater was studied. To avoid instability in the biological treatment method due to temperature changes during the year, especially in the summer. The obtained wastewater treatment plant validation was verified by applying the existing plant planning in GPS-X 8.0 modeling and simulation software, by combining biological and chemical removal methods to improve the performance of a wastewater treatment plant in Khairy in Al Diwaniyah, Iraq (KWWTP). The results showed that a series of conditions for anaerobic, oxygen and aerobic reactors help to remove biological nutrients efficiently. The concentration of COD, BOD and TSS were below the permissible environmental parameters. The removal rate of nitrogen as N-NH3 is 92.96; 94.93; 97.60% respectively. The phosphorous removal rate is 80.22, 86.55, 92.30 respectively Except for the release of nitrogen and phosphorous compounds during the summer (July and August) due to the sensitivity of phosphorous-containing organisms to the influence of temperature. The increasing concentrations of phosphorous produced in the summer were treated by adding doses of chemicals (alum) at different stages of the wastewater treatment plant, and the required dose of Alum ranges in the range of 0.5-0.9 kgAl / kg P, according to the dose strategy that achieves the highest efficiency of the KWWTP.