Comprehensive review and compilation of pretreatments for mesophilic and thermophilic anaerobic digestion

摘要

Organic matter hydrolysis prior to anaerobic digestion has been shown to improve biogasnproduction (30–50%) and reduce solids (20–60%) by ultrasound, chemical, conventional heating,nand microwave pretreatments. Numerous studies have been performed to determine the extent ofndigestion improvement but few focus on financial feasibility of these processes. A comprehensivenmodel was created using Microsoft Excel and its Visual Basic Assistant to evaluate pretreatmentnpermutations for conventional wastewater treatment plants. The four above-mentioned processesnwere evaluated for energetic and financial demands. Well-established energy equations andnwastewater characteristics, both average and high, were used. Average and high flows were 460nand 750u0002103 m3/d, respectively. Net costs per influent flow for ultrasound, chemical, conventionalnheating, and microwave were 0.0166, 0.0217, 0.0124, 0.0119 $/m3 and 0.0264, 0.0357, 0.0187, andn0.0162 $/m3 for average and high conditions, respectively. The average cost increase from resultsnexcluding pretreatment use for all processes was 0.003 and 0.0055 $/m3 for average and highnconditions, respectively. No matter the permutation, pretreatments requiring more energy tonachieve required hydrolysis levels were costlier. If energetic recoveries are substantial,ndewaterability is positively affected, and solids meet environmental constraints to be handled andndisposed at lower costs, pretreatments can be viable.