WANGGuanghui,LIXueyi,ZHANGXing,et al.Analysis and Suggestions on the Causes of High Biochemical Sludge Concentration in Typical Municipal Sewage Treatment Plants in China[J].China Water & Wastewater,2026,42(12):64-70.
Analysis and Suggestions on the Causes of High Biochemical Sludge Concentration in Typical Municipal Sewage Treatment Plants in China
China Water & Wastewater[ISSN:1000-4062/CN:12-1073/TU]
volume:
第42卷
Number:
第12期
Page:
64-70
Column:
Date of publication:
2026-06-17
- Keywords:
- sewage treatment; sludge activity; grit removal efficiency
- Abstract:
- Over 60% of municipal sewage treatment plants in China face excessive mixed liquor suspended solids (MLSS) concentrations coupled with low sludge activity (MLVSS/MLSS ratio ≈50%, significantly below the theoretical optimal range of 70%-75%) in biochemical treatment units, leading to reduced treatment efficiency, increased energy consumption and operational costs. This study systematically analyzes operational data from 22 sewage treatment plants in northern China and global literature to identify root causes of elevated MLSS across the entire treatment process, including influent characteristics, pretreatment efficiency, biochemical reaction mechanisms, advanced treatment, and sludge disposal. Key findings reveal three interdependent factors， including high inorganic particle loading in influent (ISS/SS = 39.85%, with about 70% of fine particles ≤100 μm), inadequate grit removal efficiency in pretreatment units (fine particle removal in cyclonic/aerated grit chambers, <50%), chemical sludge recirculation, and improper sludge retention time (SRT) regulation (135% MLSS surge at SRT= 90 days). To address these challenges, an integrated “source control-process optimization-smart regulation” strategy is proposed, aiming to provide a theoretical foundation and practical paradigm for improving treatment quality and efficiency, and green development in municipal sewage treatment plants.
Last Update:
2026-06-17