Impact of source-separation of urine on treatment capacity, process design, and capital expenditure of a decentralised wastewater treatment plant. (August 2022)

• Record Type: Journal Article
• Authors: Badeti, Umakant; Jiang, Jiaxi; Almuntashiri, Abdulaziz; Pathak, Nirenkumar; Dorji, Ugyen; Volpin, Federico; Freguia, Stefano; Ang, Wei Lun; Chanan, Amit; Kumarasingham, Sanjay; Shon, Ho Kyong; Phuntsho, Sherub
• Is Part Of: Chemosphere. Volume 300(2022)
• Publication Date: 2022-08
• Subjects: Decentralised wastewater treatment -- Source separation of urine -- Nitrogen removal -- Wastewater treatment capacity -- Capital costs; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2022.134489
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: In this study, the impact of urine diversion on the treatment capacity, treatment process, and capital costs of a decentralised wastewater treatment plant (WWTP) was simulated using BioWin. The data for simulation including for economic analysis were obtained from a real decentralised WWTP at Sydney. Simulation was conducted for two alternative process design scenarios of a WWTP: membrane bioreactor (MBR) without denitrification and anaerobic MBR in place of aerobic MBR and compared to existing process design. The simulation shows that with about 75% urine diversion (through source separation), the treatment capacity of the existing WWTP can be doubled although above 40% urine diversion, the impact appears less rapid. When the urine diversion exceeds 75%, it was found that the anoxic tank for biological denitrification becomes redundant and the current wastewater treatment process could be replaced with a simpler and much less aeration intensive membrane bioreactor (MBR) producing similar effluent quality with a 24% reduction in capital expenditure (footprint) cost. Anaerobic MBR can be a potential alternative to aerobic MBR although pre-treatment becomes essential before reverse osmosis treatment for water reuse applications. Sensitivity analysis has revealed that by operating the bioreactor at higher mixed liquor suspended solids concentrations (9 g/L instead of 5 g/L) could help increase the WWTP treatment capacity by about 3.5 times at 75% urine diversion. Hence, urine diversion (until nitrogen-limiting conditions occur above 75% urine diversion) can increase the treatment capacity of an existing WWTP and reduce the capital expenses due to reduced plant footprint. Graphical abstract: Image 1 Highlights: Modelled impact of urine diversion (UD) on treatment capacity, process design & CAPEX. BioWin modelling showed that with 75% UD, treatment capacity can be almost doubled. Above 75% UD, a simple aerobic MBR is adequate for wastewater treatment. 24% of the current capital costs can be reduced with urine diversion. At higher MLSS, UD significantly increases treatment capacity of WWTP.