Search

Abstract Palm oil mill effluent (POME), wastewater generated from palm oil production, is known for its extremely high chemical oxygen demand and brownish color. Anaerobic digestion is the primary treatment method for POME in the palm oil industry; however, anaerobically treated POME has high concentrations of residual contaminants and color intensity. This study proposes an approach to treat anaerobically-treated POME in recycled water for industrial applications by integrating preliminary organic precipitation, electrocoagulation, and electrooxidation (EO). The EO process was optimized in terms of the current density, electrolysis time, electrode arrangement, and feed flow rate. At a current density of 60 mA/cm2 and an electrolysis time of 9 min, the EO process with a graphite anode and stainless-steel cathode in the monopolar electrode configuration reduced the phenolic concentration and color in the preliminary-treated POME from 8.95 mg/L and 317.19 ADMI to 0.25 mg/L and 26.10 ADMI, respectively. Additionally, the EO process exhibited a 92.26% efficiency in lowering the ammonium-nitrogen content.

Fouling has become the main problem in long-term application of ultrafiltration (UF) membrane for water and wastewater treatment, significantly reducing membrane productivity. In this paper, fouling on polysulfone-based membrane was analyzed using Hermia’s model during textile wastewater treatment. The UF membrane has been prepared by blending polysulfone (PSf), acetone, and PEG400 in DMAc, with ZnO nanoparticles at a concentration of 1% by weight of polymers (PSf and PEG400). The influence of polysulfone concentration (18 and 20 wt.%) and PEG400 (0 - 25 wt.%) on fouling mechanisms was investigated. It was found that the increase of polysulfone from 18 to 20 wt.% reduced permeate flux from 54 to 25 L.m-2.h-1. Vise versa, the increase of PEG400 concentration enhanced the permeate flux. More stable flux was achieved when 18 wt.% of polysulfone was used to prepare the UF membrane. The fouling type in the UF membrane depends on the characteristics of the membrane. A significant flux decline occurred when used 20 wt.% of polysulfone without the addition of PEG400. Smaller membrane pore and higher hydrophobicity due to high polysulfone concentration induced cake layer of fouling on the membrane surface at the first 40 minutes of ultrafiltration. Further increase of operating time, internal fouling was formed due to the movement of pollutants to the permeate side caused by different concentrations. The highest color rejection (86%) was achieved when 25 wt.% of PEG400 was added in 20 wt.% of polysulfone solution. Keywords: fouling, hermia model, ultrafiltration, wastewater treatment.

Most rivers have been contaminated by household and industrial wastes that are harmful to human health. In this research, electrocoagulation (EC) and tight ultrafiltration (tight UF) processes were integrated and used to treat the contaminated river water. The EC reactor was designed and equipped with an agitator system. The EC system was operated in continuous mode at a constant flow rate of 500 mL.min−1. Meanwhile, the tight UF membrane was polysulfone-based, which had a tight structure in the surface layer. The influence of applied current in two configurations of electrodes and the operating pressure of the membrane system was investigated. It was found that a high effluent quality was achieved when 4 anodes and 2 cathodes were used in the EC reactor at a current density of 7.4 mA.cm−2 and operating pressure of 15 psig in the tight UF membrane. The removal efficiency of the integrated EC-tight UF in reducing TDS, turbidity, BOD, and COD was 72.20%, 99.11%, 94.35%, and 81.55%, respectively. Operating cost of 0.83 US$.m−3 was achieved when the water production capacity of the EC-UF plant was designed for 150 m3.d−1, a current density in EC system of 7.4 mA.cm−2, and permeate flux in the tight UF membrane system was 50 L.m−2.h−1. The operating cost was decreased to 0.49 US$.m−3 when the production capacity was increased to 600 m3.d−1.

Wastewater reclamation and reuse have become an alternative to saving operational costs while reducing the impact of waste pollution. In this paper, integration of electrocoagulation (EC) and polysulfone-based ultrafiltration (UF-PSf) membranes were used for the mentioned purpose. The EC unit equipped with 7 (seven) pieces of E-shaped of Al electrodes, which operated at a current of 3 (three) Amperes and a residence time of 2 (two) hours. The waste samples obtained from textile and oil palm industries. The experimental results were compared based on product quality and economic feasibility. When used for textile waste treatment, the integrated EC-UF units reduced TDS, TSS, BOD, and COD by 77%, 95%, 70 -80%, and 60-70%, respectively. While in palm oil waste treatment, the TDS and TSS reduced by 92% and 98%. The electrode loss rate in palm oil waste treatment was 2 (two) times greater than textile waste. By assuming that the waste production capacity of both industries was 400 m3/day, the water production cost in textile waste treatment was Rp. 4,000/m3. While in the palm oil waste treatment, the water production cost was Rp. 6,000/m3. These results showed that the EC-UF unit could be used as an economical and environmentally friendly alternative process for reclamation of industrial wastewater that meets the clean water quality standards. Keywords: electrocoagulation, industrial wastewater, ultrafiltration, reclamation, reuse water