International Journal of Technology 12(4) 770-780 (2021) Received December 2020 / Revised February 2021 / Accepted April 2021 International Journal of Technology http://ijtech.eng.ui.ac.id Treatment of Batik Industry Wastewater Plant Effluent using Nanofiltration Titik Istirokhatun 1,2 , Heru Susanto 1,3* , M. Arief Budihardjo 2 , Elda Septiyani 2 , Aditya Rahmat Wibowo 2 , Eva Fathul Karamah 4 1 Membrane Research Center, Integrated Laboratory for Research and Services, Universitas Diponegoro, Jl. Prof. Soedarto, Tembalang Semarang 50275, Indonesia 2 Department of Environmental Engineering, Faculty of Engineering, Universitas Diponegoro, Jl. Prof. Soedarto, Tembalang Semarang 50275, Indonesia 3 Department of Chemical Engineering, Faculty of Engineering, Universitas Diponegoro, Jl. Prof. Soedarto, Tembalang Semarang 50275, Indonesia 4 Department of Chemical Engineering, Faculty of Engineering, Universitas Indonesia, Kampus UI Depok, Depok 15424, Indonesia Abstract. In this study, the removal of dyes, sulfide, and some other components in batik wastewater using a nanofiltration (NF) membrane was investigated. Remazol red (RR dye), indigosol brown (IB dye), and sodium sulfide (Na2S) were used as models of synthetic batik wastewater. Furthermore, NF performance for treating real batik wastewater was also examined. The effects of operating conditions on flux and rejection were investigated. The results showed that all filtration had similar permeate flux behavior, where rapid flux decline was observed at the initial filtration, followed by gradual flux decrease and then reaching a stable flux. The rejections of the pollutant model during NF of synthetic wastewater were 61–76%, 90–95%, and 90–99% for sulfide, IB, and RR, respectively. The color rejection in real batik wastewater was 99.84%. Further, the removal of chemical oxygen demand (COD) reached 87.6%. Keywords: Batik wastewater; Dye removal; Fouling; Nanofiltration; Sulfide removal 1. Introduction Batik is the largest home-based textile industry in Indonesia. Batik is a decorated textile product that combines both art and craft (Anjani et al., 2013; Soesanti and Syahputra, 2016). In principle, selected areas of the cloth are blocked out using hot wax, and the remaining is then dyed or decorated. Thereafter, the dyed cloth is washed to remove the wax using water. The areas covered with wax resist the dye and remain in the original color. Increased batik demand affects the growth and development of batik industry centers in various regions in Indonesia. It consumes much water for the dyeing, fixing, and washing processes. Consequently, many wastewaters containing dye, wax, and other chemicals are produced. It is commonly known that the esthetic nature of water and aquatic photosynthesis is disturbed by the presence of dyes and alkaline conditions. Furthermore, the presence of color hinders aquatic plant and fish growth. More importantly, most dyes used in the batik * Corresponding author’s email: heru.susanto@che.undip.ac.id, Tel.: +62-247460058; Fax.: +62-247480675 doi: 10.14716/ijtech.v12i4.4645