Design and start-up experiences of 19,000 m~3/d Camp de Tarragona-Vilaseca Water Reclamation Plant

摘要

Within the current and future world's water scarcity, the reuse of treated waste water for specific applications offers an appealing alternative to conventional fresh water sources that cannot meet the expectations, mostly in terms of quantity. Spain is no exception to this global situation, with a constantly increasing population, in combination with growing water demand for applications such as production industry, exportation oriented agriculture, tourism development, and booming construction, access to sufficient quantities of fresh water is currently a rising concern. Camp de Tarragona (ACA) Water Reclamation Project is a prime example how water scarcity can be solved regionally by reclaiming water that would otherwise be discharged to the sea. The new reclamation plant treats municipal secondary effluent from Tarragona and Salou/Vilaseca Wastewater Treatment Plants to supply process water for the petrochemical industry of Tarragona. The plant capacity is currently 19,000 m~3/d (Phase Ⅰ), and further expansions are planned for increases up to 29,000m~3/d (Phase Ⅱ) and even to 55,000 m~3/d (Phase Ⅲ) in the coming years. This additional supply would replace the water currently taken from the Ebro River, thus releasing this volume for drinking water supply to the population. Utilizing such a process, the industrial growth in water scarce regions can be supported and industry sustainability is increased further. A pipeline connects the two different Waste-water Treatment Plants (WWTPs), 10 km apart from each other, and feeds secondary treated effluent to the reverse osmosis (RO) pretreatment process. The pretreatment consists of ballasted flocculation, followed by disc filtration, sand filtration, and multimedia filtration prior feeding it to the two pass RO system. Final permeate treatment is done by UV light and chlorine disinfection, prior releasing water to the distribution system. This paper will review the detailed design of the plant, as a scale-up of pilot plant results, as well as the RO membranes performance data obtained during the start-up of the installation. RO performance is evaluated in detail taking into account the performance differences when different combinations of raw water sources were used. This paper will also explain in detail the preservation of the installation by means of 5-Chloro-2-Methyl-2H-Isothiazol-3-one/2-Methyl-2HIsothiazol-3-one (CMIT/MIT), during a medium term stop of the plant.