Generating unconventional water resources under full Palestinian control, such as treated wastewater, is a way of by-passing the political status quo, alleviating water insecurity as well as providing alternatives to farmers in the face of growing aridity. However, all attempts on wastewater reuse were in vain due to many reasons and illegal irrigation practices with partially treated influent in certain areas still impose serious health hazards and environmental problems.
Recently the best method used and proved rapid detection of enteric viruses in wastewater was qualitative real time PCR and (qPCR), for its high sensitivity and specificity. Detection of enteroviruses needs specific virus strains depending on the chosen targeted DNA/RNA sequences using specific primers and probes. Occurrence and concentration of viruses in sewage can be affected by many factors such as water usage, season and incidence of infection among the population. Need for virus detection was important because they may cause public health hazards, enterovirus may cause respiratory tract infection and meningitis, rotavirus, adenovirus, and norovirus may cause gastroenteritis and adenovirus causes respiratory diseases, eye infection and sometimes causes meningitis.
The aim of my Thesis first to identify the efficiency of three different wastewater plants, particularly pathogen removal and specifically pathogenic human viral removal. It also aims to see if there was any correlation between the removal of enteric viruses in sewage and the removal of other microorganisms like bacteria and protozoa using faecal coliform as an indicator. The case study was concentrated mainly in Ramallah governorate, Al-Tireh Membrane Bioreactor (MBR), Al-Bireh Activated sludge (AS), and Moving Bed Bioreactor (MBBR) in Rawabi. Second, was reclaimed effluent safe enough to be used as unconventional water source, for example agricultural irrigation. The sampling was in march 2019 ,72 grab sample 0.5 liter collected at three different time intervals) and the sum of samples at the end was 24 composite samples procedure worked was polyethylene glycol (PEG) with NaCl for precipitation and concentration of influent and effluent samples, followed by extraction for both DNA and RNA nucleic acids using NucliSens system of all samples and lastly qualitative real Time qPCR (Taq-man) using the automated 7500 Real Time PCR system in Al-Caritas baby hospital in Bethlehem, using special primers and probes for the four mentioned viruses, (q PCR) Qualitative Polymerase Chain reaction method works as a multiple amplification cycles by which template DNA was first denatured followed by annealing of oligonucleotide primers target specific sequences. Tag-Man probes were used which gave a fluorescent labelled at the 5’. The main outcomes of the assessment made for physical parameters TSS removal efficiency was 99%, 98% for Al- Bireh and Rawabi WWTP’s respectively. For BOD removal 97%, 96%, 95% for Al- Bireh, Al- Tireh, and Rawabi WWTP’s respectively. For the biological parameters log removal of fecal coliform (FC) indicator,2.65 log removal of Al- Tireh, 1.75 log removal for Al- Bireh and 2.92 log for Rawabi. Detection of enteric viruses in the three WWTP’s under investigation Al- Tireh effluent had 100% removal efficiency of the four different viruses enterovirus, adenovirus, norovirus and rotavirus, while Al-Bireh effluent was 33% and 33% removal adenovirus and rotavirus respectively. Finally for Rawabi effluent 100% contamination with adenovirus, 33% removal efficiency of norovirus, and 66% removal of rotavirus. That means there was no correlation between the fecal coliform indicator and virus removal indicator and to prevent public health hazards mentioned before further tertiary treatment should be added for Al- Bireh and Rawabi WWTP’s. Disinfection alone with UV light and chlorine was not enough and this was confirmed from previous studies, for example adenovirus was resistant to chlorine, that means the removal efficiency was from the type of treatment and not from chlorine disinfection, in Al-Bireh there was no chlorine disinfection and the UV light not working and there was 100% removal of norovirus and 33% removal of adenovirus and rotavirus respectively. The pores of the membrane in Al-Tireh membrane bioreactor technology are very small (nominal pore size of the immersed hollow fiber was 0.04 micron) and does not allow the tiny viruses (0.01-0.3um sizes) to pass through, the submerged membrane in Al-Tireh act as a tertiary treatment since not only the physical and chemical parameters match with the guidelines but also the biological parameters are also met. Finally the Palestinian Water Authority (PWA), must take in charge changes in the guidelines of treated wastewater saving ground water and the environment from contamination, because as we have seen from the outcomes of this thesis, enteric viruses in treated and partially treated wastewater may threaten public health.