Research On Post-treatment Technology For Processing High Quality Drinking Water From Membrance Seawater Desalination

Reverse osmosis seawater desalination technology is an important way to solve the shortage of fresh water resources.Reverse osmosis membrane could remove the salt and other harmful substances form seawater.In the meantime,the membrane process will remove significantly Ca and Mg which are useful components for human body.Thus,the desalinated water has low alkalinity and hardness.It is not only tasteless,but also has strong causticity.There often appears the phenomenon of"red”water,because the desalinated water dissolves the network scale layer.It will affect the normal use of the residents.It is necessary to add an appropriate post-treatment technology before the desalinated water enters the water pipe or produces bottled water to deal with the desalinated water,in order to improve the mineral matter(Ca²⁺,Mg²⁺)and alkalinity of the desalinated water,which has an important effect on the safety of drinking water.In this paper,to study the portable and large reverse osmosis desalination device desalting water post-treatment technology be based on determining the key indicators high quality direct drinking water restrictions.Providing technical support of processing for desalination of water.The main research contents and results are as follows:1.Conducting about the commercially available bottled drinking water and used direct drinking water quality index testing and sensory evaluation,determine the key to high quality direct drinking water quality indexes of limit:calcium ion concentration is 30⁵0 mg/L,magnesium ion concentration is 10²0 mg/L,TDS is 100²00 mg/L,alkalinity is 10²0mg/L2.According to the portable device for the quality of the the desalinated water,researching the mineralization prescription of process and making bottled mineralization solvent.This study used CaCl₂,MgCl₂ and NaHCO₃ reagent as raw material to determine dilution water mineralizing agent formula is CaCl₂ is 5g/L,MgCl₂ is 2g/L,NaHCO₃ is 2g/L.3.In view of the large reverse osmosis seawater desalination varieties,respectively study the technology of carbon dioxide and sulfuric acid method of dissolving ore mineralization.On the one hand,to determine the optimum process parameters of CO₂ dissolved limestone by the amount of carbon dioxide,by the lime stone particle diameter,by the mineral filler height and by the speed of desalinated water.Results show that,CO₂ and desalinated water volume ratio of mineralized water quality impact is most significant,when the CO₂ and desalinated water volume ratio is 1:10,the desalinated water flow velocity is 2 m/h,the mineral filler height is 600mm,the mineralized water conform to the high quality direct drinking water standards.On the other hand,to determine the optimum process parameters of sulfuric acid dissolved limestone by the pH value,by the lime stone particle diameter,by the mineral filler height and by the speed of desalinated water.The Results show that,the pH of desalinated water of mineralized water quality impact is the most significant,when the pH of desalinated water is 2.5,the lime stone particle diameter is 10-15mm,the desalinated water flow velocity is 2 m/h,the mineral filler height is 400mm,the mineralized water conform to the high quality direct drinking water standards.