A pilot scale high-rate contact stabilization process with primary sedimentation for energy-neutral wastewater treatment

Demir E. K., Sancar D., ÇALLI B., SEMERCİ N., ŞAHİNKAYA E.

Process Safety and Environmental Protection, cilt.201, 2025 (SCI-Expanded) identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 201
  • Basım Tarihi: 2025
  • Doi Numarası: 10.1016/j.psep.2025.107625
  • Dergi Adı: Process Safety and Environmental Protection
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, Aerospace Database, Aqualine, Aquatic Science & Fisheries Abstracts (ASFA), Biotechnology Research Abstracts, CAB Abstracts, Chemical Abstracts Core, Chimica, Communication Abstracts, Compendex, Environment Index, Food Science & Technology Abstracts, Greenfile, INSPEC, Metadex, Pollution Abstracts, Veterinary Science Database, Civil Engineering Abstracts
  • Anahtar Kelimeler: Carbon capture, COD fractionation, Contact stabilization, Energy neutrality, High-rate activated sludge, Pilot scale
  • Marmara Üniversitesi Adresli: Evet

Özet

This study investigates the organic carbon removal performance and carbon recovery potential of a pilot-scale high-rate contact stabilization (HiCS) process with primary sedimentation (PS+HiCS), implemented at an advanced biological wastewater treatment plant (WWTP). COD fractionation of the grit chamber effluent revealed particulate, colloidal, and dissolved COD fractions of 74, 2, and 24 %, respectively. The PS+HiCS process was operated continuously at a flow rate of 1 m3/h for 214 days, with SRTs ranging from 0.63 to 2 days. HRTs were maintained at 23 min in the contact tank (CT) and 72 min in the stabilization tank (ST). Dissolved oxygen (DO) concentrations in both tanks were controlled at 1–3 mg/L, except for the SRT of 0.63 days when CT was intentionally kept non-aerated. A total COD removal efficiency of 85 % was achieved, and the COD oxidation reduced to 12.5 %. COD was captured with an efficiency of up to 65 % at 1 day of SRT. At an SRT of 0.88 days, the process demonstrated a net energy gaining potential of 0.32 kWh/m3 with < 100 mg/L effluent COD. This study highlights that domestic wastewater can be treated in an energy-neutral or energy-positive manner using the proposed PS+HiCS process, providing a sustainable solution for wastewater management.