Anaerobic membrane bioreactor (AnMBR) and biochar technologies have rarely been used in pesticide wastewater treatment, their performance and feasibility need further confirmation. This study compared a novel AnMBR (R2) with ferromagnetic biochar derived from traditional Chinese medicine residues to a conventional AnMBR (R1) without ferromagnetic biochar, focusing on degradation of organosulfur pesticide wastewater characterized by high toxicity and COD content and observing biogas production under various temperatures and hydraulic retention times (HRTs). The relationship between wastewater toxicity (COD, ethylene thiourea (ETU), cyanide, total manganese (TMn) and total zinc (TZn)) and biogas production was also explored. The optimal parameters were determined, with R1 and R2 having the same effect. Compared to R1, ETU removal in R2 increased from 40.7 % to 61.0 % (10 °C), from 64.6 % to 71.6 % (15 °C), from 76.9 % to 87.0 % (25 °C), and from 86.4 % to 92.4 % (35 °C). Similarly, the HRT was 48 h at 15 °C in R2 and at 25 °C in R1, both achieving a comparable COD removal of approximately 75.2 %. Cyanide removal in R2 was 2.4–9.6 % higher than in R1 across various temperatures. In addition, compared to R1, effluent concentrations of TMn in R2 were reduced by 378.8 ± 96.2 mg/L at 25 °C with the HRT of 18 h. The TZn average enhancements removal in R2 were higher than those in R1 by 6.6 % (10 °C), 10.0 % (15 °C), 3.8 % (25 °C), and 4.1 % (35 °C). Importantly, biogas production in R2 increased by 5.3–15.9 % at 25 °C. There was a significant negative correlation between biogas production and the concentrations of ETU and cyanide. This highlighted the dual benefit of R2 in enhancing pollutant degradation and biogas energy recovery, providing basic data for energy-efficient and low-carbon operations in pesticide wastewater treatment.