Stone cutting is one of the most important manufacturing industry in Iran. Wastewater from stone cutting contains suspended particles and stone powders, which reuse of waste water reduces the efficiency of the devices and tarnishes the stone, as well as environmental effects. One of the wastewater treatment methods is using coagulants and the coagulation process, which is used to increase the rate of settling of suspended and dissolved solids and reduce water turbidity. The purpose of this research is to investigate the effectiveness of organic and inorganic coagulants in the treatment of wastewater from the quarrying industry. Four types of granite, yellow travertine, white travertine and marble waste from stone factories located in Mahmoud Abad industrial town of Isfahan were sampled in 20 liter containers and transported to the laboratory of Isfahan University of Technology. Jar test was used to determine the type and optimal concentration of zeolite, polyaluminum chloride, iron chloride, aluminum sulfate (alum), anionic and cationic polyacrylamide for the coagulation process. To eva‎luate the efficiency of each of the coagulants, turbidity, EC and pH parameters were measured by RSM response surface test design method. The obtained results showed that all six coagulants were effective in removing turbidity and dissolved and suspended solid particles from the wastewater. The highest amount of turbidity removal related to anionic polyacrylamide is 98.1% and the lowest removal rate is related to zeolite with 16.5%. Finally, the optimal conditions for the superior coagulant material were determined in terms of substance concentration and mixing conditions, and the amount of dissolved and suspended solid particles and total solids in the effluent were measured. Among the three coagulants used in the optimization, the highest removal percentage of total solids, dissolved solids (TDS) and suspended solids (TSS) is related to anionic polyacrylamide coagulant with 98.6% for yellow travertine wastewater and the lowest The removal percentage related to polyaluminum chloride coagulant is 89.1% for white travertine effluent. The optimal values for coagulants of zeolite, polyaluminum chloride and iron chloride are 200 mg/L, 100 mg/liter for aluminum sulfate, and 0.5 mg/L for anionic polyacrylamide. Came. In general, based on the findings of this research, the use of coagulants for the treatment of wastewater from stone-quarry industries should be done according to the type of wastewater and coagulant.

نوراله ميرغفاري , محمد نعمتي ورنوسفادراني

محسن سليماني امين آبادي , حسين مرادي