Water desalination unit with improved protocols to produce mineral-balanced alkaline water

Water desalination is a common practice to achieve the overarching goal of augmenting the goal for providing drinking water. Reverse osmosis (RO) has been practiced commercially. During desalination, the salinity is lowered – which is desired – but the concentrations of nutritious constituents are also be reduced excessively—which is undesirable. Specifications for ideal drinking water should be: total dissolved solid: 350-525 ppm; Na+: 30-60 ppm; Mg2+: 20-30 ppm; Ca2+: 50-70 ppm; K+: 5-15 ppm; Cl-: 50-75 ppm; SO42−: 100-150 ppm; and CO32- /HCO3−: 100-125 ppm. In case of RO desalinated water product water contains low concentrations of nutritious minerals (Mg2+, Ca2+ K+, SO42 −, and CO32-/HCO3-), while the relative proportions of Na+ and Cl− are very high. Remineralisation is one approach to correct the imbalance but this is not practiced always. In RO unit, TDS of the product water has been controlled by small amount by-pass of reject stream, in which NaCl is the major constituent. Thus, development of a methodology that enables desalination to be conducted with better retention of nutritious ions would be of considerable interest. We developed ED process for the separation of mono- and bivalent ions employing polyaniline (PANI)-modified interpolymer type of ion-exchange composite membranes. Due to sieving and hydrophobic effects, the PANI coating demonstrated to improve the retention of nutritious minerals in the desalinated water.

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The technology scalable with productivity of desalinated water from 10 LPH to 500 LPH, and suitable for domestic as well as societal uses. Cost of such electrodialysis units may vary from Rs. 30,000/ to Rs. 15,00,000/ depending on productivity.

Eco-friendly

Surface/ground water

Ion exchange membrane making facilities.

Depends on the scale of manufacturing; Will be available on request

Design for domestic ED unit for mineral-balanced potable water. Ion-exchange membranes preparations