Modeling-based performance evaluation of novel cascade cum trickling filter wastewater treatment system

Optimization of operational parameters of wastewater treatment system using the modeling technique may lead to enhance the system’s operational and treatment efficiency. The present research was carried out to investigate the treatment efficiency of conventional trickling filter (CTF) and cascade cum trickling filter (CCTF) for treatment of domestic wastewater. Both the systems (CTF and CCTF) were operated for a period of four months under temperature range of 21–48 °C. The maize cob (MC) and date palm fibre (DPF) were used as biofilm support media. Biological oxygen demand (BOD) reaction kinetic model was developed and evaluated for optimization of BOD removing efficiency of CTF and CCTF. The removing efficiency of CTF and CCTF has increased with increasing operational time from 12 to 48 h. The CCTF showed 3–25% higher efficiency in removing organic matter, nutrients and sulphates compared to CTF regardless the supporting media. Similarly, MC showed 3–8% higher removal efficiency of the tested parameters compared to the DPF as supporting media in both CTF and CCTF systems. The BOD reaction kinetic model estimated the optimal volumetric design BOD loading rates (Bvd) of 1.5–2.1 kg BOD/m3 day for designing efficient trickling filter systems. The CCTF with MC media was found efficient than other reactors due to highest BOD removal efficiency (91.8%) and good capacity to treat high BOD load (2.1 kg/m3.day). Hence, the CCTF system has higher potential for efficient removal of organic and inorganic contaminants from the wastewater in developing countries.