The impact of faecal sludge-derived biochar as an additive on anaerobic degradation of synthetic human excreta
File(s)
Published version
Author(s)
Qiu, Mengru
Koulouri, Maria Eleni
Sioné, Laure
Templeton, MR
Type
Journal Article
Abstract
Pit latrine filling poses a major challenge in developing countries. This study investigated the effect of faecal sludge-derived biochar (FSB) on anaerobic degradation, the dominant process in pit latrines, using synthetic human excreta under laboratory conditions simulating wet pit environments. Results show that FSB addition significantly increased hydrolysis rate and shortened lag phase by up to 1.5 days. However, this enhancement did not translate into improved overall degradation, as volatile solids (VS) reduction decreased under FSB addition, while only minor changes were observed in methane and total gas production This decoupling is attributed to redistribution of organic carbon from gaseous products toward microbial biomass and extracellular matrices, as reflected by elevated extracellular polymeric substance (EPS) carbohydrate concentrations. Microbial community analysis revealed a targeted restructuring toward biofilm-associated hydrolytic and methanogenic populations under FSB amendment, characterised by enrichment of metabolically versatile methanogens (Methanosarcina) and proteolytic fermenters. Overall, these findings indicate that FSB promotes microbial aggregation and stabilised anaerobic processes but does not enhance net solids degradation, and therefore the findings do not support the recommendation of FSB as a pit latrine additive for reducing pit filling.
Date Issued
2026-06-01
Date Acceptance
2026-04-09
Citation
Environmental Science: Water Research & Technology, 2026, 12 (6), pp.1794-1809
ISSN
2053-1400
Publisher
Royal Society of Chemistry
Start Page
1794
End Page
1809
Journal / Book Title
Environmental Science: Water Research & Technology
Volume
12
Issue
6
Copyright Statement
© 2026 The Author(s). Published by the Royal Society of Chemistry This article is licensed under a Creative Commons Attribution 4.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.
License URL
Publication Status
Published
Date Publish Online
2026-04-14