In this study, acidic latex wastewater containing high average zinc and acetic contents of 816mgL −1 and 20,862mgCODL −1 , respectively, was treated successfully by a series of chemical and biological processes without any addition of acid or base for pH adjustment. Total dissolved solids of the treated effluent increased by only 1.1-fold on average for sulfide precipitation as compared to 2.8-fold for the hydroxide strategy. The oxidation–reduction potential (ORP) value of 0mV was used successfully as an indicator for optimum sulfide addition which consistently provided an appreciable reduction in effluent concentrations to less than 1 and 2mgL −1 for zinc and residual sulfide, respectively. The anaerobic filter was very stable in handling the chemically treated wastewater up to the organic loading rate of 11.8gCODL −1 day −1 with an average efficiency of 92%. Methane production and biomass yield were 0.32L(gCOD removed ) −1 and 0.014gVSS (gCOD removed ) −1 , respectively. For the activated sludge process, the optimum sludge age and hydraulic retention time were 30 and 0.8 days, respectively, which are equivalent to the organic loading rates of 2.50gCODL −1 day −1 or 2.13gBODL −1 day −1 . Under these optimum conditions, average removal efficiencies for COD and BOD were 96.6 and 99.4%. Average soluble COD, BOD and suspended solids in the effluent were 71, 11 and 38mgL −1 , respectively. This integrated treatment scheme was proven to be an effective approach for highly polluted and toxic rubber thread wastewater.