Methanosarcina thermophila bioaugmentation and its synergy with biochar growth support particles versus polypropylene microplastics in thermophilic food waste anaerobic digestion.

Both biochar supplementation as well as bioaugmentation have been shown in literature to improve the methane yield of anaerobic digestion. In this study, the combination of both are evaluated by growing Methanosarcina thermophila on biochar support particles prior to augmentation of thermophilic food waste anaerobic digestion. Biochar stand alone, bioaugmentation solely, a combination of both added separately or grown together, and utilizing polypropylene (PP) microplastics as growth support instead were all tested when starting up a thermophilic process from mesophilic inoculum. Methanosarcina thermophila and biochar supplementation displayed synergy, with 5% M. thermophila on 1 g/L biochar presenting a 32% increase in specific methane yield over the control. Double the bioaugmentation dosage/concentration was also trialled with a thermophilic inoculum, and 10% M. thermophila grown on 2 g/L biochar displayed the best results with a 20% increase specific methane yield from its control standard.

Understanding and optimization of the flocculation process in biological wastewater treatment processes: A review.

In the operation of biological wastewater treatment processes, fast sludge settling during liquid-solids disengagement is preferred as it affects effluent quality, treatment efficiency and plant operation economy. An important property of fast settling biological sludge is the ability to spontaneously form big and dense flocs (flocculation) that readily separates from water. Therefore, there had been much research to study the conditions that promote biological sludge flocculation. However, reported findings have often been inconsistent and this has possibly been due to the complex nature of the biological flocculation process. Thus, it has been challenging for wastewater treatment plant operators to extract practical information from the literature. The aim of this review is to summarize the current state of understanding of the factors that affect sludge flocculation so that evaluation of such information can be facilitated and strategize for intervention in the sludge flocculation and deflocculation process.