Effects of lime addition on sewage sludge composting process

Jonathan W C WONG*, Min Fang

*Corresponding author for this work

Research output: Contribution to journalJournal articlepeer-review

151 Citations (Scopus)


Previous study showed that co-composting sewage sludge with lime would effectively reduce the availability of heavy metals in the sludge compost. In the present study, effects of addition of lime on the microbial activities of sewage sludge composting were evaluated in a bench-scale in-vessel system through monitoring biological parameters including microbial respiration, microbial populations (thermophile and mesophile), and activities of related enzyme (dehydrogenase, alkaline phosphatase, β-glucosidase, and urease). Lime raised the pH of the sludge compost effectively at the initial period, and this effect became less obvious with an increase in composting time. Adverse effects of lime amendment on all biological parameters increased with an increase in lime application rates, but these effects were generally restricted to the early stage of the thermophilic phase. Addition of 0.63% lime prior to sludge composting slightly improved the microbial activity as indicated by the higher temperature and CO2 evolution and did not exert a significant inhibition on bacterial population, and the activities of β- glucosidase, alkaline phosphatase, and dehydrogenase after 100 days of composting. This together with our previous results on heavy metal availability supports the use of lime at a rate of < 1.0% (w/w) to co-compost with sewage sludge. (C) 2000 Elsevier Science Ltd.

Original languageEnglish
Pages (from-to)3691-3698
Number of pages8
JournalWater Research
Issue number15
Publication statusPublished - 15 Oct 2000

Scopus Subject Areas

  • Ecological Modelling
  • Water Science and Technology
  • Waste Management and Disposal
  • Pollution

User-Defined Keywords

  • Composting
  • Enzyme activity
  • Lime
  • Mesophile
  • Sewage sludge
  • Thermophile


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