Optimization of Net Energy Recovery from the Biodegradable Solid Waste in a Two-Stage Anaerobic Digestion System
Journal
Bioenergy Research
Journal Volume
19
Journal Issue
1
Start Page
18
ISSN
19391234
Date Issued
2026-12
Author(s)
Abstract
This study investigates optimization of net energy recovery from biodegradable solid waste (BSW) using a two-stage anaerobic digestion (TAD) system. BSW was pretreated by hydrolysis at 37 °C (pH 4.5–6.5), with hydraulic retention time (HRT) of 5 days and total solid (TS) concentration of 120 g/L. The liquid hydrolysate was collected, diluted, and fed continuously to a methane reactor (MR) operated at organic loading rate (OLR) of 1.9–11.4 g-TS/L/d (corresponding HRT: 15.9–3.6 d). Maximum biogas yield and methane content (327 mL/g-TS and 71.6% CH₄) were observed at the lowest OLR (1.9 g-TS/L/d) and pH 6.5; the minimum yield (193 mL/g-TS, 54.1% CH₄) occurred at pH 4.5 and the highest OLR. The relationship between operating conditions and net energy recovery was modeled using a quadratic multiple regression analysis, yielding a high correlation coefficient (R² = 0.8823). The model predicted the optimal energy recovery ∆Eoptimal was 6703 J/g-TS (1862 Wh/kg-TS) at a pH of 6.5, OLR of 5.6 g-TS/L/d, and HRT of 5.4 d. The optimized TAD configuration outperformed typical single-stage systems in net energy recovery and provides practical operating guidelines for waste-to-energy applications.
Subjects
Biodegradable solid waste
Energy recovery
Operating parameters
Two-stage anaerobic digestion
Publisher
Springer
Type
journal article