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Để có được sản phẩm nước cất đạt được tiêu chuẩn theo đúng nghĩa đen (cất 1 lần, cất 2 lần) và đạt tiêu chuẩn lý hóa thì nước cất thì người ta căn cứ vào tiêu chuẩn cơ sở do nhà sản xuất công bố và so sánh với tiêu chuẩn nhà nước, tiêu chuẩn nghành để đánh giá chấy lượng. | 304 Desalination Trends and Technologies The densimetric Froude number at the discharge must always be higher than 1 even so the installation of valves is recommended. Jet discharge velocity should be maximized to increase mixing and dilution with seawater in the near field region. The optimum ratio between the diameter of the port and brine flow rate per port is set so that the effluent velocity at discharge is about 4 - 5 m s. Nozzle diameters are recommended to be bigger than 20cm to prevent their clogging due to biofouling. To maximize mixing and dilution with submerged outfall discharges a jet discharge angle between 45 and 60 with respect to the seabed is advisable under stagnant or co-flowing ambient conditions. In case of cross-flow vertical jets 90 reach higher dilution rates Roberts et el 1987 - Avoid angles exceeding 75 and below 30 . Diffusers ports should be located at a certain height elevation above the seabed avoiding the brine jet interaction with the hypersaline spreading layer formed after the jet impacts the bottom. This port height can be set up between 0.5 and 1.5 m. The discharge zone is recommended to be deep enough to avoid the jet from impacting the surface under any ambient conditions. Avoid designs with several jets in a rosette. Riser spacing is recommended to be large enough to avoid merging between contiguous jets along the trajectory because this interaction will reduce the dilution obtained in the near field region and also because the modelling tools to simulate this merging are less feasible. - If it is necessary to build a submarine outfall and it passes through interesting benthic ecosystems a microtunnel to locate the pipeline should be constructed. - As a prevention measure modelling tools should be used for modelling discharge and brine behaviour into seawaters under different ambient scenarios. - An interesting alternative is to discharge brine into closed areas with a low water renovation rate or areas receiving wastewater
