Post-treatment options for anaerobically digested sludge : Current status and future prospect

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review

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  • Zhiyao Wang
  • Tao Liu
  • Haoran Duan
  • Yarong Song
  • Xi Lu
  • Shihu Hu
  • Damien Batstone
  • Min Zheng


Original languageEnglish
Article number117665
Journal / PublicationWater Research
Online published14 Sept 2021
Publication statusPublished - 15 Oct 2021
Externally publishedYes


Anaerobic digestion is the most commonly used sludge treatment technology in large-scale wastewater treatment plants (WWTPs), generating two main products, i.e., biogas and anaerobically digested (AD) sludge. Biogas can be used as a source of renewable energy, and AD sludge is often transported for agricultural land application. Land application of AD sludge is confronted with ever-increasing economic and regulatory pressures due to its high water content, high organic content and related odour and pathogen content (if poorly stabilized), as well as potential toxic metal and organic contaminants. To address these challenges, a number of technologies have been developed for the further treatment of AD sludge before final disposal. This review aims to critically evaluate these state-of-the-art technologies. These technologies were categorized based on their primary aims: 1) dewaterability enhancement; 2) solids reduction and stabilization; 3) toxic metals removal. At present, the goal of post-treatment mainly focuses on dewaterability enhancement, to reduce transport costs. In future, we propose that the post-treatment of AD sludge should orient towards multiple aims, i.e., an integrated approach enabling sludge volume reduction, stabilization (including pathogen removal), and metal solubilization simultaneously. Two promising technical routes are suggested as examples, i.e. physio-chemical iron-based advanced oxidation and biological acidic aerobic digestion, while more approaches need to be developed in future studies. We concluded that post-treatment of AD sludge will promote the AD sludge management towards a more economically favourable, socially acceptable, and environmentally sustainable way; however, further development and rigorous evaluation are required for a wider adoption. © 2021 Elsevier Ltd. All rights reserved.

Research Area(s)

  • Anaerobically digested sludge, Dewaterability, Solids reduction, Stabilization, Toxic metals removal

Citation Format(s)

Post-treatment options for anaerobically digested sludge: Current status and future prospect. / Wang, Zhiyao; Liu, Tao; Duan, Haoran et al.
In: Water Research, Vol. 205, 117665, 15.10.2021.

Research output: Journal Publications and Reviews (RGC: 21, 22, 62)21_Publication in refereed journalpeer-review