Integrated bipolar electrocoagulation and PVC-based ultrafiltration membrane process for palm oil mill effluent (POME) treatment

In this study, the effectiveness of integrating electrocoagulation (EC) and ultrafiltration (UF) membranes for palm oil mill effluent (POME) wastewater treatment was investigated. The impact of various parameters on contaminant removal efficiency, including electrode configuration (monopolar and bipolar), number of anodes, agitation rate, and current density, was studied. The findings demonstrated that using bipolar (BP) electrodes in the EC reactor improved coagulation efficiency. However, an increase in agitation rate led to a decrease in removal efficiency. The electrode configuration of 2A-2C-2B achieved high contaminant removal with a lower electrode consumption compared to the 4A-2C and 4A-2C-2B configurations. The removal efficiencies for total dissolved solids (TDS), total suspended solids (TSS), chemical oxygen demand (COD), and biological oxygen demand (BOD) were 59.1%, 99.9%, 96.8%, and 96%, respectively. The operating cost for the electrode configuration of 2A-2C-2B was estimated to be 2.71 US$ m-3 at an effluent capacity of 50 m3 d-1 and 20 h d-1 of operating time, while the energy requirement was 6.20 kWh m-3. An increase in operating time from 5 to 24 h d-1 raised the specific operating cost from 2.17 to 2.85 US$ m-3. This study provides valuable insights into optimizing EC and UF processes for POME wastewater treatment, which could have significant implications for sustainable industrial practices.

Performance and economic evaluation of a pilot scale embedded ends-free membrane bioreactor (EEF-MBR)

In this work, an embedded ends-free membrane bioreactor (EEF-MBR) has been developed to overcome the fouling problem. The EEF-MBR unit has a novel configuration where a bed of granular activated carbon is placed in the bioreactor tank and fluidized by the aeration system. The performance of pilot-scale EEF-MBR was assessed based on flux and selectivity over 140 h. The permeate flux fluctuated between 2 and 10 L.m^-2.h^-1 under operating pressure of 0.07-0.2 bar when EEF-MBR was used to treat wastewater containing high organic matter. The COD removal efficiency was more than 99% after 1 h of operating time. Results from the pilot-scale performance were then used to design a large-scale EEF-MBR with 1200 m³.day^-1 capacity. Economic analysis showed that this new MBR configuration was cost-effective when the permeate flux was set at 10 L.m^-2.h^-1. The estimated additional cost for the large-scale wastewater treatment was about 0.25 US$.m^-3 with a payback period of 3 years. KEY POINTS: • Performance of new MBR configuration, EEF-MBR, was assessed in long term operation. • EEF-MBR shows high COD removal and relatively stable flux. • Cost estimation of large scale shows the cost effective EEF-MBR application.