Desiliconization of drinking water by modified media filtration

Summary

A brief evaluation of water desiliconization technologies is given. The results of experimental investigations of eliminating silicic acid compounds from water by deposition on aluminum and iron hydroxides, contact coagulation in a granular bed and modified media filtration are presented. Activated aluminum oxide filtering media modified with 0.5% sodium aluminate solution attains twice as much sorption capacity (compared to media regeneration with alkali) in relation to orthosilicates. Herein 95–97% desiliconization efficiency is ensured alongside with simultaneous reduction of water hardness. Non-waste technology of underground water desiliconization with modifying chemical reuse and generation of crystalline dewatered alumosilicate used in ceramics production as process wastes was developed.

Key words

potable water , filtration , loading material , sodium aluminate , desiliconization , activated aluminum oxide , alumosilicate sludge

Desiliconization of ground water at the deironing-demanganization facilities

Summary

The results of investigating the technology of desiliconization of ground water typical for the Tyumen North are presented. It was found that efficient elimination of siliceous, ferriferous and manganese compounds is ensured in the process of water treatment with potassium permanganate in alkalescent environment with subsequent coagulation with AQUA-AURAT™30 polyoxychloride. However, the dosage of coagulant required to provide for the permissible silicon concentration is relatively high. Therefore, additional clarification means (e.g. two-stage filtration) shall be retrofitted into the process flow scheme. Residual aluminium concentration in filtrate did not exceed Maximum Permissible Concentration (MPC).

Key words

coagulant , potassium permanganate , alkalizing reagent , cold low-mineralized ground water , desiliconization , deironing-demanganization

Removal of silicon compounds from underground water by filtration through a modified media

Summary

A brief analysis of water desiliconization technologies is given. The results of experimental studies on the removal of silicic acid compounds from water by filtration through a modified media are presented. It is shown that the use of a filtering media made of activated alumina modified with 0.5% sodium aluminate solution acquires a sorption capacity twice as high as the media regenerated with alkali in relation to orthosilicates, and provides for 95–97% water desiliconization while reducing in-parallel the water hardness. The sorption capacity of the modified activated alumina in relation to silicon is 16kg in terms of SiO₂ per 1 m³ of sorbent, which is twice as much in silicon holding capacity compared with the technology of desiliconization by regeneration of activated alumina with caustic soda. The working exchange capacity of the modified activated alumina in terms of the absorbed total hardness is 300–350 g-eq/m³, which is comparable to sulfonated carbon and KU-1 cation exchanger. A non-waste technology of desiliconization of groundwater with re-using the modifying chemical agent generated in the form of dehydrated crystalline aluminosilicate as a commercial raw material for the production of ceramic products has been developed.

Ключевые слова

potable water , filtration , sodium aluminate , desiliconization , activated aluminum oxide , alumosilicate sludge , media modification