en Water quality and wastewater treatment and reuse Original articles <div style="text-align: justify;"><span style="font-size:12pt"><span style="line-height:115%"><span style="font-family:&quot;Times New Roman&quot;,&quot;serif&quot;"><b><i><span style="font-size:10.0pt"><span style="line-height:115%"><span style="color:black">Introduction:</span></span></span></i></b><b> </b><span style="font-size:10.0pt"><span style="line-height:115%"><span style="color:black">The most important pollutant in surface water sources is turbidity. </span></span></span><span style="font-size:10.0pt"><span style="line-height:115%"><span style="color:black">The aim of the study is to determine the most effective thyme plant extract as a natural coagulant to remove water turbidity and compare it with alum as a chemical coagulant.</span></span></span><span style="font-size:10.0pt"><span style="line-height:115%"><span style="color:black">. </span></span></span></span></span></span><br> <span style="font-size:12pt"><span style="line-height:115%"><span style="font-family:&quot;Times New Roman&quot;,&quot;serif&quot;"><b><i><span style="font-size:10.0pt"><span style="line-height:115%"><span style="color:black">Materials and Methods:</span></span></span></i></b><b> </b><span style="font-size:10.0pt"><span style="line-height:115%"><span style="color:black">In this study, plant extracts obtained from Thymus vulgaris (Tv), Thymus kotschyanus (Tk), and Thymus eriocalyx (Te) were used as natural coagulants for elimination of water turbidity. Then, the best of plant extract was confirmed by ninhydrin and FTIR analyses and the </span></span></span><span style="font-size:10.0pt"><span style="line-height:115%"><span style="color:black">effect </span></span></span><span style="font-size:10.0pt"><span style="line-height:115%"><span style="color:black">of simultaneous use of plant extract with chemical coagulant of aluminum sulfate (alum) was investigated in the hybrid ratio of 1:1, 2:1, and 1:2. Then, the effect of parameters include of pH, coagulant dose, turbidity removal efficiency, and the most suitable solvent for coagulant extraction were studied. </span></span></span></span></span></span><br> <span style="font-size:12pt"><span style="line-height:115%"><span style="font-family:&quot;Times New Roman&quot;,&quot;serif&quot;"><b><i><span style="font-size:10.0pt"><span style="line-height:115%"><span style="color:black">Results:</span></span></span></i></b><b> </b><span style="font-size:10.0pt"><span style="line-height:115%"><span style="color:black">The results of this study showed that among the natural coagulants, Tv had a higher efficiency in elimination of water turbidity, and the highest amounts of turbidity elimination for Tv, alum, and Tv/alum hybrid coagulants was 94, 90, and 96, respectively. According to the results of this study, the most effective solvent for preparing plant extracts was 1M KCl solvent.</span></span></span></span></span></span><br> <b><i><span style="font-size:10.0pt"><span style="line-height:150%"><span style="font-family:&quot;Times New Roman&quot;,&quot;serif&quot;"><span style="color:black">Conclusion:</span></span></span></span></i> </b><span style="font-size:10.0pt"><span style="line-height:150%"><span style="font-family:&quot;Times New Roman&quot;,&quot;serif&quot;"><span style="color:black">The natural coagulant removes more turbidity from water than the chemical coagulant, and the simultaneous use of natural and chemical coagulants with a 1:1 ratio was more effective.</span></span></span></span></div> Thymus, Natural Coagulant, Water turbidity, Conventional coagulant 2341 2353 http://jehsd.ssu.ac.ir/browse.php?a_code=A-10-776-1&slc_lang=en&sid=1 Hossein Kamani Hossein_kamani@yahoo.com 0000-0002-1498-9580 No Infectious Diseases and Tropical Medicine Research Center, Research Institute of Cellular and Molecular Sciences in Infectious Diseases, Zahedan University of Medical Sciences, Zahedan, Iran. Leili Mohammadi lailimohamadi@gmail.com 0000-0003-1979-4800 No Infectious Diseases and Tropical Medicine Research Center, Research Institute of Cellular and Molecular Sciences in Infectious Diseases, Zahedan University of Medical Sciences, Zahedan, Iran. Ali Azari azari.hjh@gmail.com 0000-0002-6004-6954 No Sirjan School of Medical Sciences, Sirjan, Iran Seyed Davoud Ashrafi d_ashrafi@yahoo.com 0000-0002-9726-5456 No Department of Environmental Health Engineering, Research Center of Health and Environment, School of Health, Guilan University of Medical Sciences, Rasht, Iran Farah Heydari No Iranian Academic Center for Edueaction, Cultur and research (ACECR),Sistan and Baluchestan brach,Iran Fatemeh Ganji No Student Research Committee, Zahedan University of Medical Sciences, Zahedan, Iran Seyed Mohammad Mousavi SMM9080@yahoo.com 0000-0001-9561-8011 Yes Student Research Committee, Zahedan University of Medical Sciences, Zahedan, Iran