Review on industrial wastewater energy sources and carbon emission reduction: towards a clean production

This review provides an innovative approach of treating palm oil mill effluent (POME) from open pond and closed anaerobic sludge reactor for generation of green energy in the form of biogas containing methane. Improper techniques for the treatment and management of POME produce hazards to people and contribute to global warming. In all over the world, the total crude oil palm production in the countries like Malaysia, Indonesia, Africa, Latin America, Asian countries, Solomons and other were around 51, 31, 7, 6, 3, 2 and 1% compared with soya 41.8% and coconut 3.48%, respectively. In the year 2014–15, Malaysia generated at least 87.8 million tonnes of palm effluent per year. Various studies reveal that about 80% of palm effluent is disposed off partially treated in open dumps. The generated certified emission reductions (CERs) estimated and favoured the treatment of POME in anaerobic reactor by replacing open lagoon of aerobic system for cleaner production. The clean development mechanism (CDM) encourages the utilisation of upflow anaerobic sludge blanket reactors for POME treatment and methane capture to earn CER credits as a source of revenue.     

Extrication of biodiesel feedstock from early stage of food waste liquefaction

Biodiesel is commonly produced from vegetable oils, mostly edible and more expensive than petroleum diesel. By considering the cost of the conversion processes, cheap feedstock such as triglycerides and fatty acids (FA) extracted from early stage of food waste liquefaction has become a better choice than vegetable oils, as it could provide high yield of biodiesel without any compromise to food supply and other resources. In this study, FA from early stage of food waste liquefaction was extracted and tested for use as feedstock for biodiesel synthesis. The raw material was not pretreated but extraction was done by dry and wet methods. It was found that wet method could minimized the lost of short and medium-chained FA as well as reducing the number of steps required, thus, yielding higher amount of FA as feedstock. The effects of mixing, methanol ratio, reaction time and catalyst content were investigated for the acid-catalyzed esterification. The maximum biodiesel conversion obtained was 97.4 %.