Evaluating the biomethane potential from the anaerobic co-digestion of palm oil mill effluent, food waste, and sewage sludge in Malaysia

Resource recovery and valorization of food wastewater for sustainable development: An overview of current approaches

The food processing industry is one of the world's largest consumers of potable water. Agri-food wastewater systems consume about 70% of the world's fresh water and cause at least 80% of deforestation. Food wastewater is characterized by complex composition, a wide range of pollutants, and fluctuating water quality, which can cause huge environmental pollution problems if discharged directly. In recent years, food wastewater has attracted considerable attention as it is considered to have great prospects for resource recovery and reuse due to its rich residues of nutrients and low levels of harmful substances. This review explored and compared the sources and characteristics of different types of food wastewater and methods of wastewater treatment. Particular attention was paid to the different methods of resource recovery and reuse of food wastewater. The diversity of raw materials in the food industry leads to different compositional characteristics of wastewater, which determine the choice and efficiency of wastewater treatment methods. Physicochemical methods, and biological methods alone or in combination have been used for the efficient treatment of food wastewater. Current approaches for recycling and reuse of food wastewater include culture substrates, agricultural irrigation, and bio-organic fertilizers, recovery of high-value products such as proteins, lipids, biopolymers, and bioenergy to alleviate the energy crisis. Food wastewater is a promising substrate for resource recovery and reuse, and its valorization meets the current international policy requirements regarding food waste and environment protection, follows the development trend of the food industry, and is also conducive to energy conservation, emission reduction, and economic development. However, more innovative biotechnologies are necessary to advance the effectiveness of food wastewater treatment and the extent of resource recovery and valorization.

Methane Biogas Production in Malaysia: Challenge and Future Plan

Biomethane is a sustainable energy that is produced from an organic and renewable resource. As the second-largest oil palm producer in the world, palm oil mill effluent (POME) is the primary source of biomethane generation in Malaysia. POME is the by-product of palm oil extraction and is extensively employed as a feedstock for the production of biomethane. Malaysia has an equatorial environment with humid and hot weather; this climate is conducive to the cultivation of numerous agricultural crops. A considerable number of agricultural wastes and residues are produced by agricultural crops, however, only 27% of them are used as fuel or to create useable products. Several publications have been published on the production of biomethane from POME; nevertheless, additional research is required on the use of other bioresources and technologies for biomethane production in Malaysia. In addition, there is a lack of comprehensive information on the future development of biomethane production in Malaysia; thus, to fill this gap, this review paper focuses on the challenges and future of Malaysia, which puts an emphasis on POME and also includes other alternative options of bioresources that can be the future feedstock for biomethane production in Malaysia. To the best of our knowledge, this is the first paper to provide a comprehensive overview of the biogas trend in Malaysia in terms of challenges and current biomethane development, as well as detailed information on a number of leading companies that are currently active in Malaysia biogas industry.

Alkyl polyglycosides enhanced the dark fermentation of excess sludge and plant waste to produce hydrogen: performance and mechanism

Alkyl polyglycosides (APG), a biodegradable biosurfactant, have been widely used in environmental pollution control. However, the application of APG to enhance anaerobic dark fermentation of excess sludge (ES) and plant waste (PW) to improve hydrogen production has not been reported so far. In order to fill this gap, the effect of APG on hydrogen production from ES and PW was studied in mesophilic (30 °C) environment. The results showed that APG increased the yield of hydrogen, and the recommended dose was 0.15 g/g (calculated as volatile suspended solids), accompanied by 18.7 mL/g. The contribution of APG self-degradation to hydrogen can be ignored. Mechanism investigation revealed that APG promoted the dissolution, hydrolysis, and acidification of complex organic matter, and when the content of APG was 0.15 g/g, the concentration of dissolved chemical oxygen demand (COD) was as high as 3151 mg/L; however, the dissolved concentration of COD in the blank group was only 1548 mg/L. In addition, APG improved the output of volatile fatty acids (VFA). APG promoted the proportion of acetate and butyrate in VFA, which was conducive to hydrogen production. As for the process of methanogenesis, APG reduced the consumption of hydrogen and accumulates hydrogen. This work provides an alternative strategy for the recycling of organic waste and the enhanced generation of hydrogen.