performance evaluation of tile wastewater treatment with different coagulants

introduction: the objective of this study was, wastewater quality investigation and removal efficiency of contaminants from the wastewater tile factory by using  coagulants includes ferric chloride, ferric sulfate and ferrous, aluminum sulfate and poly aluminum chloride in order to reuse it in the processing line. methods: this is an applied study. with regard to shiftwork schedules of the factory, the composite samples of wasrewater in production line was obtained. firstly, based on standard methods wastewater parameters were measured . in the next step by using the jar- test  the effect of changing coagulants dosing(0.15, 0.2, 0.25, 0.3, 0.35g/l)  and ph values (7,9,11) on the removal parameters of turbidity, ec, tss, ts and cod was investigated. finaly the effective dose and optimal ph were selected and the best coagulant was determined. results:the optimum ph of ferric chloride, ferric sulfate and ferrous that optimum was 11as well as it was 7 for aluminum sulfate and poly aluminum chloride. the optimum concentration of iron-based coagulants and  aluminum-based coagulants was 0.3 g/l and 0.25 g/l, respectively. poly aluminum chloride with removal  of  99.92% , 99.94%, 89.8 and 75% has the best removal efficiency for turbidity, tss, ts and cod, respectively. in addition, in a lower dose aluminum sulfate, ferrous sulfate, ferric chloride and ferric sulfate had the best removal efficiency. conclusion: among the five studied coagulants, poly aluminum chloride, aluminum sulfate and ferrous sulfate had the most efficiency, respectively. due to the high cost of aluminum chloride,  it needs more accuracy to select the most suitable coagulant