بررسی اثر منعقدکننده ها در حذف CODوTSS شیرابه زباله کارخانه کمپوست اصفهان

Introduction: Untreated leachate is being discharged into the environment in many countries worldwide. Leachate treatment methods have not been unified so far due to variable composition of leachate in different sites. Lack of control as well as disregarding leachate treatment and disposal of it can cause environmental pollution. This study aimed to investigate the Coagulants' effect on the COD (Chemical Oxygen Demond) and TSS(Total Suspended Solids) removal from Isfahan composting leachate. Ferrous sulfate, Ferric chloride,Poly ferric sulfate, Alum and Poly aluminium chloride were used in addition to two cationic and anionic commercial co-coagulants. Methods: In this experimental study, leachate samples were collected from the Isfahan composting leachate collection ponds. At first, Leachate characteristics were measured according to standard methods. Jar-test experiments were carried out to examine the effects of changing coagulants' dosage (0/5,1,1/5,2,2/5 and 3 g/l) and PH values (4,5,6,7,8,9,11 and 12) on COD and TSS removal. As a result, the effective dosage, optimum pH and the most convenient coagulant were identified. Results: According to the results, polyferric sulfate reached the highest COD and TSS removal efficiency were at pH= 11, with 2 g/L of poly ferric sulfate, the COD removal efficiency was 49% while the dosage of 2.5 g/l of this coagulant levelled at 51% of TSS removal efficiency.The co-coagulant K350CF, while used along with polyferric sulfate, reached the highest level in COD and TSS removal efficiencies which were 53% and 52% respectively.The highest COD removal efficiency using co-coagulant LT25 was related to poly-aluminum chloride, equal to 49% . Conclusion: The most effective coagulant for COD and TSS removal was polyferric sulfate which contributed to better results with an alkaline pH. From the results obtained, it may be stated that Coagulation-flocculation can be used as a convenient inexpensive pretreatment process to treat Isfahan composting leachate, processing the leachate for a better and more convenient treatment compared with other methods.