Efficiency of the rubber sheet wastewater treatment is dependent on PNSBsi, FPE and RT. The results demonstrated that RT had a significant effect on the reduction of COD and SS values whereas the PNSBsi strongly reduced TtS [Equation 4, Equation 5, Equation 6]. RT is one of the major factors, which controls the degradation of carbonaceous wastes as it represents the length of time the microbial cells are in contact with the substrate, which directly dictates the efficiency of wastewater treatment [24]. In this case, it ensures that the PNSBsi had enough time to consume most of the substrate and nutrients over the RT of 4 d. There was a significant reduction of TtS caused by the PNSBsi because some members of the PNSB can use sulfide or other reduced forms of sulfur as an extra source of an electron donor to support photosynthesis [5,10]. COD value was also dependent on the interactive relationship between PNSBsi vs. FPE and PNSBsi vs. RT [ Equation 4], this again illustrated that FPE stimulated PNSB growth as previously described.