Recently, due to the abundance of carbon, nitrogen and phosphorus in municipal sewage sludge (MSS), the energy potential of MSS has become increasingly prominent. Economically developed regions possess more financial and policy support advantages for the development of MSS energy recovery technology; hence, the selection of the appropriate sludge treatment and disposal technologies to maximize the energy potential of MSS is of great importance. In this study, the energy recovery potential of MSS was evaluated on the basis of regional economies, sludge analysis, a main sludge energy reuse technology review and legislative profile analysis. As the most commonly adopted technology, incineration had a lower energy potential, which may be ascribed to the high moisture content, high disposal costs and difficulties in in situ energy recovery. In contrast, the energy potential for anaerobic digestion, pyrolysis and gasification was relatively high. By conducting a SWOT-FAHP analysis, management evaluation of these four technologies was carried out from the following four perspectives: problem solving, technology development, ecological environment and laws and regulations. Pyrolysis was evaluated to be the most suitable technology from the technical and environmental perspectives because its products had high energy potential and avoided heavy metal problems. The obstacles and problems that pyrolysis technology might encounter in commercial applications in the future are discussed. With this energy-generating, low energy consumption, low-pollution sludge energy reuse technology, the potential of sludge pyrolysis would be high in the long run. These results revealed the factors affecting the energy recovery potential of sludge, and comprehensively evaluated the technologies from the aspects of problem solving, environmental impact, technology development and law, the optimal solution obtained could provide reference on the management decision of sludge disposal technology for economically developed areas in the future.

In recent years, the production of municipal sludge has gradually increased, and finding suitable sludge treatment and disposal technologies is an urgent problem that needs to be solved. Bio-drying of sludge is a relatively efficient and convenient drying method, but currently, there are still problems with unstable drying effects and high moisture content of dried products, which limits the subsequent utilization of bio-drying products. This article uses a thermal assisted bio-drying device that simulates carbonization waste heat reflux, and uses corncob, straw, sawdust, and rice husk as conditioners to carry out bio-drying of dehydrated sludge. The influence of the types and ratios of conditioner under thermal assistance on the bio-drying of dehydrated sludge is explored. The results showed that the moisture removal efficiency of the corncob and straw groups was better, and their material moisture content could be reduced to below 10% within 24 h. The lower calorific value of straw-sludge drying products was the highest, at 11,608.8 kJ/kg. The best conditioner under the conditions of this experiment was straw, and the drying effect was best when the mass ratio of dehydrated sludge to straw was 4:1. The research results contribute to promoting the development of sludge bio-drying technology.