Constructed wetlands combined with UV disinfection systems for removal of enteric pathogens and wastewater contaminants

Abstract

Water shortage is an ongoing cardinal issue in the Middle East region. Wastewater reuse offers some remediation, but to-date many rural communities in the Palestinian Authority (PA) and in Jordan are not connected to centralized wastewater treatment plants (WWTPs), many of them are disposing of their wastewater using infiltration septic tanks. This highlights the need for a small, local, low cost WWTP that can directly benefit local communities, producing effluents suitable for unrestricted irrigation. Constructed wetlands (CWs) could offer a solution as they are relatively easy and cheap to construct and maintain, and effective in removal of many pollutants. Nevertheless, pathogen removal in CWs is often not adequate, calling for additional disinfection. Here we describe the use of low-cost, consumer level, UV based disinfection systems coupled to CWs for wastewater treatment in three CWs: in Israel, Jordan and in the PA. Once mature, our adapted CWs reduced chemical oxygen demand (COD) load, and, given proper use of the UV systems, inactivated indicator bacteria (faecal and E. coli) to levels suitable for irrigation, even when UV transmission (UVT) levels were low (∼40%). Our results demonstrate the promise in this combined treatment technique for cheap and simple wastewater treatment suitable for the Middle East region.

Integrated wetlands for food production

“…A simple integration of CTW into a recirculating hatchery was conducted by Buřič et al (Buřič et al, 2015) in the Czech Republic that different from traditional RASs which generally involve specialized technologies, such as microsieve filtration, ozonization, and UV sterilization (Azaizeh et al, 2013;Good et al, 2011;Sharrer et al, 2010;Terjesen et al, 2013). This study indicated that CTW integration has the potential to increase production (potential final biomass with CW use was estimated to be 40% greater than without CW use) of a recirculating hatchery without added operational or environmental costs.…”

A review of incorporation of constructed wetland with other treatment processes

“…Therefore, by combining CWs with MBR, UV ( Fig. 4 (a)) or membrane chemical reactors (MCRs), for example, the effluent quality can meet the guidelines of WHO for reuse in agriculture [6,65].…”

“…Azaizeh et al [65] tested CWs combined with UV disinfection for removal of enteric pathogens and wastewater contaminants. CWs could remove, on average, 75% of COD and 1-2 log-unit fecal.…”

Fate of Environmental Pollutants

“…Stabilized wetland system efficiently treated the COD. The UV system coupled with the wetland was able to inactivate indicator bacteria (fecal and E. coli) to levels suitable for irrigation even at low UV transmission (Azaizeh et al, 2013).…”