Zinc Removal from ZnO Industrial Wastewater by Hydroxide Precipitation and Coagulation Methods: The Role of pH and Coagulant Dose


  • Ratnawati Ratnawati Institut Teknologi Indonesia




Zn, pH, coagulant, turbidity, COD


Liquid waste from the ZnO industry must be treated to meet the quality standards of wastewater into water bodies, according to the Minister of Environment Regulations No.5, 2014. It still contains 79 mg/L of Zn metal, cloudy with turbidity above 500 NTU, and COD value around 222 mg/L. This study aims to determine the effect of pH on reducing Zn metal and the coagulant dose to minimize turbidity and COD in liquid waste produced by the ZnO factory in Depok, West Java. The waste treatment has been carried out by adding alkaline to neutralize the acid conditions in the equalization basin. However, the results have not met the requirements. It is necessary to vary the pH (8.5; 9.0; 9.5; 10.0 and 10.5) to precipitate of Zn optimally, modify the dose of coagulants (50; 100 and 150 mg/L) and reaction times (10; 15 and 20 minutes) to reduce its turbidity and COD concentration. The best results were obtained at a pH of 9.5 with a coagulant dose of 50 mg/L and a reaction time of 10 minutes. This condition can reduce Zn concentration (79 to 3.71 mg/L), turbidity (557 to 1.42 NTU), COD (222 to 68 mg/L) with a removal efficiency of 95.3%; 99.7%; and 69.4% respectively. These values have met the standard requirements according to government regulations.


Azimi, A., Azari, A., Rezakazemi, M., Ansarpour, M. “Removal of Heavy Metals from Industrial Wastewaters: A Review”. ChemBioEng Reviews, vol 4(1), 37-59, 2017

Badan Standarisasi Nasional SNI 06.6989.2:2009 Air dan Air Limbah-Bagian 2: Cara Uji Kebutuhan Oksigen Kimiawi (Chemical Oxygen Demand/COD) dengan Refluks Tertutup secara Spektrofotometri, Badan Standarisasi Nasional, Jakarta.

Badan Standarisasi Nasional SNI 6989.25:2005 Air dan Air Limbah-Bagian 25: Cara Uji Kekeruhan dengan Nefelometer, Badan Standarisasi Nasional, Jakarta.

Badan Standarisasi Nasional SNI 6989.72:2009 Air dan Air Limbah-Bagian 72: Cara Uji Kebutuhan Oksigen Biokimia (Biochemical Oxygen Demand/BOD), Badan Standarisasi Nasional, Jakarta.

Baloch, A., Qaisrani, Z.N., Zahid1, I., Hussain, S., Mengal, A.N., Sami, S.K., Amin, M., Siddique, M., Sultan, S.H. “Removal of Zinc (II) from municipal wastewater using chemically modified activated carbon developed from Rice husk and Kikar charcoal”. Journal of Applied and Emerging Sciences, vol 9(1), 2019.

Bongiovani, M.C.,Camacho, F. P., Coldebella, P.F., Valverde, K.C., Nishi, L., Bergamasco, R. “Removal of natural organic matter and trihalomethane minimization by coagulation/flocculation/filtration using a natural tannin”. Desalination and Water Treatment, vol 57(12), pp. 5406-5415, 2016.

Chen Q., Yao, Y., Li, X., Lu, J., Zhou, J., Huang, Z. “Comparison of heavy metal removals from aqueous solutions by chemical precipitation and characteristics of precipitates”. Journal of Water Process Engineering, vol 26, pp. 289-300, 2018.

Chen, Y., Lin, H., Yan, W., Huang, J., Wang, G., Shen, N. “Alkaline fermentation promotes organics and phosphorus recovery from polyaluminum chloride-enhanced primary sedimentation sludge”. Bioresource Technology, vol 294, 122160, 2019.

Eggermont, S. G. F., Prato, R., Dominguez-Benetton, X., Fransaer, J. “Metal Removal from Aqueous Solutions: Insights from Modeling Precipitation Titration Curves”. Journal of Environmental Chemical Engineering, vol 8, pp 1-8, 2020

Ghafoorisadatieh, A., Almatin, E., Bam, M. S. N., Gholipour, A. “Estimating of Optimal Dose of PACL for Turbidity Removing from Water”. Arxiv org, pp 1-8, 2019.

Ghorpade, A. Ahammed, M. M. “Water Treatment Sludge for Removal of Heavy Metals from Electroplating Wastewater”. Environ. Eng. Res, vol 23(1), pp 92-98, 2018.

Hosseinian, F., S., Irannajad, M., Azadmehr, A. R. “Removal of Zn(II) from Wastewater by Ion Flotation: Determination of Optimum Conditions”. Amirkabir Journal of Civil Engineering, vol 49(4), pp 679-686,2018.

Irfan, M., Butt, T., Imtiaz, N., Abbas, N., Khan, R. A., Shafique, A. “The Removal of COD, TSS, and Colour of Black Liquor by Coagulutation-Flocculation Process at Optimized pH, Settling, and Dosing Rate”. Arabian Journal of Chemistry, vol 10, pp s2307-s2318, 2017.

Jamshaid, M., Khan, A.A., Ahmed, K., Saleem M. “Heavy metal in drinking water its effect on human health and its treatment techniques – a review”. International Journal of Biosciences, vol 12(4), 223-240, 2018.

John, M., Heuss-Aßbichler, S., Ullrich, A. “Recovery of Zn from Wastewater of Zinc Plating Industry by Precipitation of Doped ZnO Nanoparticles”. International Journal Environmental Science Technology, vol 13, pp 2127-2134, 2016.

Lewis, A. “Precipitation of Heavy Metals”. Sustainable Heavy Metal Remediation, pp. 101-120, 2017

Malik, Q. H. “Perfomance of Alum and Assorted Coagulants in Turbidity Removal of Muddy Water”. Applied Water Science, vol 8(40), pp 1-4, 2018.

Renu, Agarwal, M., Singh, K., “Heavy Metal Removal from Wastewater using Various Adsorbents: a review”. Journal of Water Reuse and Desalination, vol 7(4), 387-419, 2017a.

Renu, Agarwal, M., Singh, K. “Methodologies for removal of heavy metal ions from wastewater: an overview”. Interdiscipline Enviromental Review, vol 18(2), 124, 2017b.

Zainuddin, N. A., Mamat, T. A. R., Maarof, H. I., Puasa, S. W., Yatim., S. R. M. “Removal of Nickel, Zinc, and Copper from Plating Process Industrial Raw Effluent Via Hydroxide Precipitation Versus Sulphide Precipitation”. IOP Conf. Series. Materealls Science and Engineering, vol 551, pp 1-6, 2019.

Zhang, X., Hao, Y., Wang, X. Chen, Z. “Rapid Removal of Zinc (II) from Aqueous Solutions using a Mesoporous Activated Carbon Prepared from Agricultural Waste”. Materials, vol 10(9), pp 1-18, 2017.

Zhang, Y., Zhang, H., Zhang, Z., Liu, C. Sun, W. Zhang, Marhaba, T. “pH Effect on Heavy Metal Release from a Polluted Sediment”. Journal of Chemistry, pp. 1- 7, 2018



How to Cite

Ratnawati, R. (2020). Zinc Removal from ZnO Industrial Wastewater by Hydroxide Precipitation and Coagulation Methods: The Role of pH and Coagulant Dose. Jurnal Riset Teknologi Pencegahan Pencemaran Industri, 11(2), 35-42. https://doi.org/10.21771/jrtppi.2020.v11.no2.p35-42



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