Table 2.
Various efficient wastewater treatment processes employed by selected countries for the eradication of SARS-CoV-2 RNA.
| Country | Treatment stage | Wastewater treatment Processes | Results | References |
|---|---|---|---|---|
| India | Secondary + tertiary treatment | – Sequencing batch reactor (SBR) + Cl2 (site: 3 and 4) | All negative | Arora et al. (2020) |
| – Moving bed biofilm reactor (MBBR) + UV (site: 5) | All negative | |||
| – Sequencing batch reactor (SBR) + without tertiary (site: 6) | All negative | |||
| Iran – Tehran | Secondary + tertiary treatment | – Extended aeration activated sludge (EAAS) system + Cl2 disinfection (Modules: 1–4) | Positive samples: 2/4 = 50.0% | Nasseri et al. (2021) |
| – Oxidation ditch method + UV disinfection (Modules: 5–6) | All negative | |||
| – Anzali | – Extended aeration activated sludge (EAAS) system + Cl2 disinfection | All negative | ||
| – Qom | – Conventional activated sludge (CAS) system with diffuser aeration + Cl2 disinfection | All negative | ||
| Japan | Secondary treatment | – Activated sludge (AS) system | Positive sample: 1/5 = 20.0% | Haramoto et al. (2020) |
| Italy (Padua, Veneto, NE Italy) | Secondary + tertiary treatment | – Activated sludge (AS) system + peracetic acid and terminal UV lamps | Positive sample: 2/2 = 100% | Baldovin et al. (2021) |
| Spain | Secondary treatment | – Activated sludge (AS) system | Positive sample: 2/18 = 11.1% | Randazzo et al. (2020b) |
| Tertiary treatment | – Coagulation, flocculation, and filtration, UV and NaClO disinfection | Positive sample: 0/13 = 0% | ||
| Spain (North–Western) | Primary treatment | – Primary settler | Positive sample: 1/2 = 50% | Balboa et al. (2021) |
| Secondary treatment | – SBR and microfiltration | Positive sample: 0/5 = 0% | ||
| USA | Secondary treatment | – Activated sludge (AS) system | Positive sample: 0/4 = 0% | Sherchan et al. (2020) |
| Tertiary treatment (Final effluent) | – Cl2 disinfection | Positive sample: 0/4 = 0% | ||
| UAE | Secondary treatment | – Activated sludge process (ASP)/clarification | Positive sample | Hasan et al. (2021) |
| Tertiary treatment | – Sand filtration, disinfection, and chlorination | None of the 11 WWTPs' treated effluents tested positive | ||
| Israel | Secondary treatment | – Activated sludge process | – ~1 log10 RNA removal by the primary and secondary treatment | Abu Ali et al. (2021) |
| Tertiary treatment | – Sand filtration and disinfection through chlorination | – > 100 copies/L of SARS-CoV-2 RNA remained the secondary effluent | ||
| Saudi Arabia | Secondary treatment | – Activated sludge (AS) system | N1: 0.3 log10 reduction (50%) | Hong et al. (2021) |
| Tertiary treatment | – Chlorination | N3: 0.5 log10 reduction (70%) | ||
| (Hospital WWTP) |