Extent of bioleaching and bioavailability reduction of potentially toxic heavy metals from sewage sludge through pH-controlled fermentation

YEŞİL H., Molaey R., ÇALLI B., TUĞTAŞ KARNABAT A. E.

Water Research, cilt.201, 2021 (SCI-Expanded) identifier identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 201
  • Basım Tarihi: 2021
  • Doi Numarası: 10.1016/j.watres.2021.117303
  • Dergi Adı: Water Research
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, PASCAL, Aerospace Database, Analytical Abstracts, Applied Science & Technology Source, Aqualine, Aquatic Science & Fisheries Abstracts (ASFA), BIOSIS, Biotechnology Research Abstracts, CAB Abstracts, Chemical Abstracts Core, Chimica, Communication Abstracts, Compendex, Computer & Applied Sciences, EMBASE, Environment Index, Food Science & Technology Abstracts, Geobase, MEDLINE, Metadex, Pollution Abstracts, Veterinary Science Database, Civil Engineering Abstracts
  • Anahtar Kelimeler: Alkaline fermentation, Dissolved organic matter, Metal solubilization, Volatile fatty acids, Waste activated sludge, WASTE ACTIVATED-SLUDGE, FATTY-ACIDS ACCUMULATION, ANAEROBIC-DIGESTION, MICROBIAL COMMUNITY, BIOGAS PRODUCTION, ALKALI TYPES, STABILIZATION, FRACTIONATION, ACIDIFICATION, DEGRADATION
  • Marmara Üniversitesi Adresli: Evet

Özet

© 2021Utilization of anaerobically stabilized sewage sludge on arable lands serve as a renewable alternative to chemical fertilizers as it enables recycling of valuable nutrients to food chain. However, probable presence of heavy metals in sewage sludge restricts the use of stabilized sludge on lands. In this study, a novel approach based on pH-controlled fermentation and anaerobic metal bioleaching was developed to reduce ecotoxicity potential of fermented sludge prior to its land application. Sewage sludge was subjected to pH-controlled fermentation process at acidic, neutral, and alkaline pH levels with the aim of increasing metal solubilization and decreasing bioavailable metal fractions through anaerobic bioleaching. Alkaline reactor performed the best among all reactors and resulted in 3-fold higher hydrolysis (34%) and 6-fold higher acidification (19%) efficiencies along with 43-fold (in average) higher metal solubilization than that of neutral pH reactor. As a result of alkaline fermentation, 32–57% of the metals remained as bioavailable and 34–59% of the metals were encapsulated as non-bioavailable within solid fraction of fermented sludge (biosolid), whereas 8–12% of total metal was solubilized into fermentation liquor. Our results reveal that anaerobic bioleaching through alkaline fermentation enables biosolid production with less metal content and low bioavailability, facilitating its utilization for agricultural purposes.