Patent ID: 9309138
Filing Date: 2016-04-12
CPC Classification: B01D,C02F

Claim Text:
1. A fresh water production method comprising treating a first raw water, wherein the first raw water is sewage, industrial wastewater, lake water, groundwater, river water or a treatment water obtained by subjecting sewage, industrial wastewater, lake water, groundwater or river water to pre-treatment other than in accordance with the fresh water production method, using a first semipermeable membrane treatment apparatus to produce fresh water and concentrated water, mixing the concentrated water produced by the treatment in the first semipermeable membrane treatment apparatus with a second raw water, wherein the second raw water is seawater, salt lake water, brine water or a treatment water obtained by subjecting seawater, salt lake water or brine water to pre-treatment other than in accordance with the fresh water production method and has an osmotic pressure higher than the osmotic pressure of the first raw water, to produce a mixed water, and treating the mixed water using a second semipermeable membrane treatment apparatus to produce fresh water, wherein a first microbicide is continuously or intermittently injected into the first raw water and a second microbicide is continuously or intermittently injected into the second raw water and wherein a third microbicide is continuously or intermittently injected into the concentrated water and, optionally, a fourth microbicide is continuously or intermittently injected into the mixed water.