The main aim of wastewater disinfection processes is the significant reduction of microorganism concentrations so as to make the receiving waters suitable either for irrigation, recreational, bathing or drinking purposes, or so that the reclaimed wastewater can be directly reused. Continuous disinfection is not always necessary if there are no specific requirements for the receiving water body; indeed, it is an exceptional practice in many countries. However, the treatment plant always needs to be equipped for emergency disinfection in case of: (i) epidemics, when microorganism concentrations of are exceptionally high or (ii) possible plant malfunction, when the effluent discharged may not be otherwise optimally treated. In recent years, a substantial amount of research has been performed with the aim of assessing existing disinfection processes and developing new solutions. Various systems have been considered: available treatments are either (i) traditional chemical and physical, including treatments with chlorine, chlorine dioxide, peracetic acid, ozone and ultraviolet irradiation; (ii) natural: constructed wetlands with subsurface or surface flow; (iii) innovative: chemical treatment by performic acid, sonication or electron beams; or a combination of two or more of the above. This review assesses the most promising wastewater disinfection treatments for use in the near future for small (< 2,000 population equivalent (PE)), medium (2,000-10,000 PE) and large (> 10,000 PE) communities, taking into consideration the intended final use of the treated effluent: from discharge into a surface water body to direct reuse. The main operational parameters, based on our experience and according to other data in literature, are also presented: concentrations, irradiation, contact time for chemical and physical systems, and hydraulic retention time and specific area (m2/PE) for natural systems, as well as investment and maintenance costs.
New Perspectives in Wastewater Disinfection
VERLICCHI, Paola;GALLETTI, Alessio;AL AUKIDY, Mustafa Tarik Kether;
2011
Abstract
The main aim of wastewater disinfection processes is the significant reduction of microorganism concentrations so as to make the receiving waters suitable either for irrigation, recreational, bathing or drinking purposes, or so that the reclaimed wastewater can be directly reused. Continuous disinfection is not always necessary if there are no specific requirements for the receiving water body; indeed, it is an exceptional practice in many countries. However, the treatment plant always needs to be equipped for emergency disinfection in case of: (i) epidemics, when microorganism concentrations of are exceptionally high or (ii) possible plant malfunction, when the effluent discharged may not be otherwise optimally treated. In recent years, a substantial amount of research has been performed with the aim of assessing existing disinfection processes and developing new solutions. Various systems have been considered: available treatments are either (i) traditional chemical and physical, including treatments with chlorine, chlorine dioxide, peracetic acid, ozone and ultraviolet irradiation; (ii) natural: constructed wetlands with subsurface or surface flow; (iii) innovative: chemical treatment by performic acid, sonication or electron beams; or a combination of two or more of the above. This review assesses the most promising wastewater disinfection treatments for use in the near future for small (< 2,000 population equivalent (PE)), medium (2,000-10,000 PE) and large (> 10,000 PE) communities, taking into consideration the intended final use of the treated effluent: from discharge into a surface water body to direct reuse. The main operational parameters, based on our experience and according to other data in literature, are also presented: concentrations, irradiation, contact time for chemical and physical systems, and hydraulic retention time and specific area (m2/PE) for natural systems, as well as investment and maintenance costs.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
