Partial decarbonisation of water esp. drinking water - by trickling water through filter and simultaneously lowering pressure to backwash filter and flowing carbon di:oxide-free inert gas through filter

摘要

Partially decarbonisation of water by pptn. of calcium carbonate in the presence of crystallisation nuclei in the form of calcium carbonate-contg. material in a filter bed of granulated solid material. Water is trickled through the filter bed with simultaneous lowering of the pressure to back wash the filter bed so that 10-20% of the calcium carbonate ppted. during decarbonisation remains in the filter bed. Inert gas practically free of CO2, pref. air is used to mechanically clean the filter during decarbonisation by flowing it through the filter bed pref. in countercurrent flow to water. The vol. ratio of water to inert gas used is 1:0.5 to 1:1.5 esp. pref. about 1:1. USE/ADVANTAGE - Esp. used for purifying drinking water. The method gives energy savings of about 25-30% and crystallisation and retention of the CaCO3 on the trigonal filter material of over 90% which reduces the amt. of rinsing water required.