Challenges and Solutions for Treated Sewage Effluent Reuse

The purpose of this work is to identify challenges associated with the treated sewage effluent (TSE) reuse in Qatar and the region. Ultimately this work aims to create a thorough knowledge base for policy makers and end users to maximise the reuse of TSE for non-potable applications. The role of TSE reuse as an alternative source of water supply is well acknowledged in Qatar. TSE generation has increased more than 3.5 times over the past seven years, and it is estimated that the surplus would reach 77 million m3 per year by 2030 [1, 2]. After adequate treatment, TSE can be effectively used for urban, agricultural and industrial applications. The degree of treatment is dictated by the end use water quality requirement. For example, nutrient free TSE is needed for district cooling applications to prevent biological growth within the system, while agricultural applications would benefit from the presence of these nutrients. Presently, district cooling industries use TSE and potable water blend for their operations. For any application, potential wastewater pollutants such as pathogens (e.g. bacteria, protozoa and virus), heavy metals (e.g. lead, mercury, arsenic, and cadmium), nutrients (e.g. phosphorus and nitrogen) and chemical of emerging concerns (Pharmaceuticals, personal care products PPCPs and endocrine disrupting chemicals EDCs) can pose significant threats to living organisms and environment. Currently, the irrigation sector and district cooling industries are the primary users of TSE in Qatar. Considering the potential benefits of TSE reuse in the agriculture sector, a pilot scheme was developed [3] and commissioned targeting the removal of emerging contaminants from TSE. Pilot train includes coagulation, flocculation, sedimentation, advanced oxidation (ozone-peroxide), UV-peroxide, sand filtration, polymer and ceramic ultrafiltration treatment processes. The concentrations of trace elements present in TSE were determined by inductively coupled plasma atomic emission spectroscopy, and the results were compared with the World Health Organization (WHO) and the Food and Agriculture Organization (FAO) reuse guidelines. Moreover, contaminants of TSE that hindered its maximum reuse potential, especially for district cooling applications, were identified by reviewing the make-up and process affected TSE water quality data. Technology screening for removing TSE contaminants was performed by considering water treatment plant footprint and costs. Experimental studies were conducted using coagulation and ion-exchange methods for phosphate removal in TSE for district cooling applications. References: [1] S.Y. Jasim, J. Saththasivam, K. Loganathan, O.O. Ogunbiyi, S. Sarp, Reuse of Treated Sewage Effluent (TSE) in Qatar, Journal of Water Process Engineering 11 (Supplement C) 2016, 174-182. [2] Hajar Farzaneh, Jayaprakash Saththasivam, Kavithaa Loganathan, Oluwaseun Ogunbiyi, Sarper Sarp, and Gordon McKay. (2016). Reuse of treated sewage effluent (TSE) in Qatar and its impact on sustainability and the environment. QScience Proceedings: Vol. 2016, QULSS 2016: Biodiversity, sustainability, and climate change, with perspectives from Qatar, 40. [3] Saad Jasim, Jayaprakash Saththasivam, Kavithaa Loganathan, Advanced Oxidation Processes for Treated Sewage Effluent 2017, Patent application no. PCT/US17/38155.