Is anaerobic digestion a feasible alternative to the combustion of olive mill solid waste in terms of energy production? A critical review

The use of olive mill solid waste (OMSW) for energy production has mainly been promoted through combustion processes. However, the EU is promoting the substitution of combustion in favor of greener alternatives. Several publications have stated that the energy obtained from anaerobic digestion (AD) is a feasible waste-to-energy technology for OMSW. However, these studies lack reliable energy balances that can assess this statement. The present research work aims to address this issue by evaluating the energy potential of the biomethanization of OMSW in comparison with the current combustion technology, based on a review of the available scientific literature. The present analysis demonstrates that the AD of OMSW can generate a net energy production in the same range as that obtained from the OMSW combustion, qualifying AD as an alternative to combustion but not clearly offering a surplus of energy production

Conversion of sewage sludge to biosolids

With the increasing generation of sewage sludge, its proper handling and disposal play a critical role in protecting our environment. Sustainable sludge treatment and management depend on controlling the quantity, quality, and characteristics of biosolids in favor of efficient sludge handling and biosolids beneficial use. One of the ultimate goals in the treatment is to convert sludge into biosolids or a product subject to subsequent treatment, in simplified operations that are cost-effective and environmentally safe. This chapter discusses the main treatment processes—clarification, stabilization, conditioning, thickening, dewatering, and drying—of sludge. The principle, operation, relevant diagrams, and criteria of each treatment method are presented. A case study of sludge management operation is also included.Omotayo S. Amuda, An Deng, Abass O. Alade, and Yung-Tse Hun