Combined anaerobic treatment of domestic wastewater and landfill leachate at psychrophilic temperatures

Cigdem Yangin Gomec, Deniz Izlen Cifci, Izzet Ozturk, Cumali Kinaci

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)


The aim of this study was to investigate the influence of low temperature on a lab-scale continuous-flow Upflow Anaerobic Sludge Bed (UASB) reactor performance treating pre-settled raw sewage and leachate (1.0% by volume) mixture, without any additional heating. The mesophilic seed was acclimatized to low temperatures with synthetic wastewater characterizing raw sewage (HRT =12 h). The reactor was then fed with raw domestic wastewater (aver-age COD tot ≅ 235 mg/L) at the same HRT. Results indicated average CODtot, and CODsol removals of 59% and 32%, respectively (OLR=0.5 kg COD/, only with raw sewage feeding. During pre-settled sewage feeding, average CODtot, and CODsol removals were observed as 14% and 37%, respectively (OLR= 0.3 kg COD/m at a HRT of 8 h. Low organic removals could be attributed to very dilute influent (weak strength) characteristics of both raw and pre-settled sewage. In the study, raw sewage and young landfill leachate (with 1.0% by volume) were mixed and pre-settled in order to increase the initial COD tot, to around 550 mg/L. Since raw sewage reflected a very weak strength character, the aim was to increase the influent organic concentration to a relatively medium strength character by leachate addition, before the psychrophilic UASB reactor was fed. Average CODtot, and COD sol removals improved and were obtained as 60% and 67% (OLR=1.3 kg COD/; HRT=10 h) respectively at room temperatures (15±3°C). Besides, average biogas production was calculated to be 0.25 m3/kg with leachate addition, whereas almost no biogas productions were observed in the cases of either pre-settled or raw domestic sewage treatment. Apparently, low influent COD resulted in low substrate levels inside the reactor, and also in a low biogas production rate. Thus, anaerobic treatability performance based on COD removals was significantly affected by influent COD concentration rather than operational temperature.

Original languageEnglish
Pages (from-to)1828-1832
Number of pages5
JournalFresenius Environmental Bulletin
Issue number11 A
Publication statusPublished - 2008


  • Combined treatment
  • Landfill leachate
  • Psychrophilic temperatures
  • Sewage
  • UASB reactor


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