The Effects of Pipe Material and Age on the Formation of Disinfection By – Products (DBP) In Nablus Water Network

Discussion Committee: 
Prof. Dr. Marwan Haddad - Major Supervisor
Dr. Laurie McNeill - Co-Supervisor
Dr. Shehdi Jodi - Internal Examiner
Dr. Maher Abu-Madi - External Examiner
Prof. Dr. Marwan Haddad
Dr. Laurie McNeill
Nabeel Abdullah Jameel Omar
In the City of Nablus which is located in the northern West Bank- Palestinian Territory, a water system network serves about 177,000 people in Nablus and some of the surrounding localities, consist of, five wells, five springs, 13 operating storage tanks,13 pump stations, distribution network consists of about 304 km of water pipes of different diameter, material and ages. The treatment process used for disinfecting drinking water is chlorination, using sodium hypochlorite, the Unaccounted for Water (UFW) is 29 % in the year of 2010, and the supply is intermittent due to water shortages, so contaminants can intrude into the pipe network and the rooftop storage tanks and react with chlorine to form disinfection by –products (DBPs), which may cause cancer and some other diseases.In this research, samples representing Nablus water system in coordination with Nablus Water Supply and Sanitation Department were taken and analyzed for content of DBPs as THM. Results show all TTHM values of the field survey samples were less than PSI MCL (250 ppb) and the USEPA MCL (80 ppb), except one value from Al Qwareen Spring trading center at 153 ppb, which is more than the MCL set by the USEPA. This mean it is very necessary to monitor continuously TTHM in this supply node and the water system and ensure not to exceed the MCL value. Pipe segments of different materials and ages were installed at the WESI laboratory and filled with water obtained from the taps at WESI, different chlorine doses, contamination loads and different incubation periods were applied to the different segments. Samples from the entire water volume incubated in the pipe segments were analyzed for their content of TTHM. Results were statistically analyzed using SPSS statistical package. Results show that TTHM values increased with increasing chlorine dose, BOD loading, and incubation time. TTHM concentration for new steel pipe samples was more than that in Polypropylene pipe samples, and increased with increasing age of pipe, but the different is not significant. Based on the results obtained, it was found that: • There is presence of TTHM in Nablus water supply system. • There are clear relationships between TTHM in water supply system with chlorine dose and residual concentration, BOD concentration and incubation period. • Old steel pipes need to be replaced. • Incubation period need to be reduced by increasing water availability and pumping durations. • Chlorine dose and residual need to be more closely monitored. • UFW must be reduced to reduce biological contamination of water.
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