Carbon monoxide reduction in the flue gas during biochar production from oil palm empty fruit bunch

Biomass carbonization technology is implemented to produce charcoal with high-calorific content. However, this technology releases pollutant gases, which adversely affect ambient environment and human health. This study proposed a catalytic gas treatment method using platinum-supported alumina catalyst (Pt/γ-Al2O3) for carbon monoxide emission reduction in oil palm empty fruit bunch carbonization. Carbonization released a rather high carbon monoxide concentration of 5558 ± 53 mg m−3 in the flue gas, exceeding the permissible limit of 1000 mg m−3. At 2.5 wt% of catalyst dosage, the carbon monoxide emission substantially was reduced to 595 ± 9 mg m−3, achieving 89.3% carbon monoxide removal efficiency. This was due to oxidation by the platinum-supported alumina catalyst (Pt/γ-Al2O3), which was done at low temperature, thus transforming carbon monoxide into carbon dioxide. The catalyst demonstrated reusability, attaining >80% carbon monoxide removal efficiency for 5 consecutive carbonization cycles. The biochar produced contained a high energy content of 24.6 ± 0.7 MJ kg−1, which was suitable to be used as a coal substitute

Convective sludge drying by rotary drum dryer using waste steam for palm oil mill effluent treatment

Achieving a more sustainable wastewater treatment plant has never been so important. Issues around energy consumption and pollutants removal efficiency are of growing importance in the context of production costs and pollution control. In the palm oil industry, more than 85% mills are managing their palm oil mill effluent (POME) via lagoons, yet the system considered less effective as the quality of the effluent hardly achieved the permissible limits. It is therefore in the best interest of the industry to employ a better practice. Convective sludge drying (CSD) has been shown to have exceptional efficiency in high-strength wastewater treatment. In this study, CSD epitomized the zero-emission of POME treatment due to the fact that; 1) It operates on low-grade steam discharged by the mill instead of electricity, leading to a huge cut on energy consumption, 2) Production of secondary micronutrients-enriched solids by-product (i.e., calcium and magnesium) that can be repurposed as fertilizer, and 3) The decoction produced can potentially be reused to irrigate the existing oil palm plantation for nutrient cycling. The treatment resulted in substantial removal of the chemical oxygen demand (COD), biological oxygen demand (BOD), suspended solids (SS), ammoniacal nitrogen (AN), and oil and grease (OG) down to 2 mg/L, 67.7 mg/L, 40.0 mg/L, 99% of BOD, COD, SS, OG, and AN removal efficiency. The operating cost was valued at USD 1.91 per m3 POME. The pilot-scale operation proved CSD is a viable alternative to the lagoons