Evaluation of microbial inoculation technology for composting

Abstract

Utilisation of microbial inoculant (MI) in composting is a bioremediation technology aiming to enhance the degradation rate and the compost quality. There is a diverse opinion about the effectiveness of MI in composting. The reproducibility of the results is a great challenge notably for an open composting system compared to a closed in-vessel system. Its efficiency is expected to be affected by the starting materials and the operating conditions. Optimising the physicochemical parameters during composting, i.e. the initial C:N, pH values, moisture content and aeration during composting was reported to be more crucial than the role of MI. This study aims to review the effectiveness of MI for the composting of two types of starting materials, i.e. the organic portion of municipal solid waste (OP-MSW) and lignocellulosic waste (LW). The potential effects of MI to enhance the composting parameters are presented. It is found that the effectiveness of MI to facilitate the composting process is depending on the type of wastes to be managed and the aims to improve the targeted quality of composting. The use of MI tends to exert a more significant positive effect on the composting of LW than the OP-MSW. There is no absolute consensus on the efficiency of MI for composting as it varies on a case-by-case basis. A decision framework is needed for the application of MI for different composting scenarios.