Objective To research the proper bicarbonate concentration for shipboard seawater reverse osmosis ( RO) remineralization. Methods Comprehensive analyses were made on the effects of HCO3- l on the desalination corrosion index, the methods of shipboard seawater reverse osmosis remineralization and related remineralization criteria. Then, the range of proper bicarbonate concentration of soft water remineralization was recommended for shipboard seawater reverse osmosis remineralization from different angles, which was verified by municipal drinking water quality survey results. Results HCO3- concentration greater than 90 mg/L could significantly reduce corrosiveness of desalinated water. Nevertheless, the contribution ration for Langelier index ( LSI) was debased when HCO3- was greater than 90 mg/L. At present, the minimum quality criteria for HCO3-concentration was equal or greater than 30mg/L proposed by most countries. Shipboard desalination remineralization was more preferable with direct addition of agent, but the dissolution of bicarbonate was quite low in water. Conclusion In consideration of the shipboard environment and support capability, the applicable bicarbonate concentration of shipboard RO desalination remineralization was 30-90 mg/L, which was within the range of drinking water bicarbonate concentration for 50％ of the cities in our country.

Objective To research the proper bicarbonate concentration for shipboard seawater reverse osmosis ( RO) remineralization. Methods Comprehensive analyses were made on the effects of HCO3- l on the desalination corrosion index, the methods of shipboard seawater reverse osmosis remineralization and related remineralization criteria. Then, the range of proper bicarbonate concentration of soft water remineralization was recommended for shipboard seawater reverse osmosis remineralization from different angles, which was verified by municipal drinking water quality survey results. Results HCO3- concentration greater than 90 mg/L could significantly reduce corrosiveness of desalinated water. Nevertheless, the contribution ration for Langelier index ( LSI) was debased when HCO3- was greater than 90 mg/L. At present, the minimum quality criteria for HCO3-concentration was equal or greater than 30mg/L proposed by most countries. Shipboard desalination remineralization was more preferable with direct addition of agent, but the dissolution of bicarbonate was quite low in water. Conclusion In consideration of the shipboard environment and support capability, the applicable bicarbonate concentration of shipboard RO desalination remineralization was 30-90 mg/L, which was within the range of drinking water bicarbonate concentration for 50％ of the cities in our country.

Objective To research and propose the proper calcium concentration for shipboard seawater reverse osmosis remineralization.Methods Comprehensive analyses were made on the calcium nutrient intake of adults,the effects of [Ca2+] level on the desalination corrosion index,the methods of shipboard seawater reverse osmosis remineralization and related remineralization criteria.Then,the range of proper calcium concentration of soft water remineralization was recommended for shipboard seawater reverse osmosis remineralization from different angels,which was verified by municipal drinking water quality survey results.Results Food was the main source of human calcium intake.[Ca2 +] concentration elevation could significantly reduce the corrosiveness of desalinated water,however,the contribution ratio for Langelier index (LSI) was debased when [Ca2+] reached 41 mg/L.Shipboard desalination remineralization was more preferable with direct added agential.At present,for the sake of health,the minimum quality criteria for [Ca2+] in soft water was 16 mg/L.Calcium chloride was commonly used for desalinated water remineralization,with the maximum permitted concentration being 36 mg/L.Conclusions In consideration of the shipboard environment and support capability comprehensively,the applicable calcium concentration of shipboard RO desalination remineralization was 16-36 mg/L,which was within the range of drinking water calcium concentration for 57％ of the cities of our countries.

Objective To research and propose the proper calcium concentration for shipboard seawater reverse osmosis remineralization.Methods Comprehensive analyses were made on the calcium nutrient intake of adults,the effects of [Ca2+] level on the desalination corrosion index,the methods of shipboard seawater reverse osmosis remineralization and related remineralization criteria.Then,the range of proper calcium concentration of soft water remineralization was recommended for shipboard seawater reverse osmosis remineralization from different angels,which was verified by municipal drinking water quality survey results.Results Food was the main source of human calcium intake.[Ca2 +] concentration elevation could significantly reduce the corrosiveness of desalinated water,however,the contribution ratio for Langelier index (LSI) was debased when [Ca2+] reached 41 mg/L.Shipboard desalination remineralization was more preferable with direct added agential.At present,for the sake of health,the minimum quality criteria for [Ca2+] in soft water was 16 mg/L.Calcium chloride was commonly used for desalinated water remineralization,with the maximum permitted concentration being 36 mg/L.Conclusions In consideration of the shipboard environment and support capability comprehensively,the applicable calcium concentration of shipboard RO desalination remineralization was 16-36 mg/L,which was within the range of drinking water calcium concentration for 57％ of the cities of our countries.