Enhanced wastewater treatment with nitrogen compounds removal in biofilters

Summary

Biofilters mainly built in Russia in 1960–1970-ies in most cases are a part of small-scale treatment facilities. At present most biofilters are in serviceable condition (owing to the specific design), however they provide for incomplete biological treatment. The results of the laboratory studies of the wastewater treatment technology in biofilters are presented. Several process flow schemes are considered, optimal modes of the facilities‘ operation are suggested. The properties of different filter media were studied. The advantages and drawbacks of the technologies and media studied are noted. Health-related and chemical parameters of the water treated are set. The diagrams that reflect running processes of nitrification-denitrification are presented. The use of a two-stage four-zone process flow scheme of biological wastewater treatment is substantiated. The suggested process flow scheme will provide for the wide use of biofilters both in upgrading the existing facilities and in designing new ones.

Key words

nitrification , biofilter , wastewater treatment , laboratory tests , loading material , ammonia nitrogen , denitrification , biofilm , enhanced treatment

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

Development of Contact Clarification Technology for Low Turbid Water Treatment

Summary

The enhancement of a single-stage flow chart of treatment of low turbid water of the Saratov Reservoir (the Volga) in contact clarifiers at the treatment facilities of the city of Samara is considered. The experience of the operation of contact clarifiers in Samara under conditions of low turbid colour water treatment shows the high efficiency of water clarification and decolouration at simultaneous reduction of the cost of construction and operation of treatment facilities in comparison with the two-stage water treatment. The process of contact coagulation progresses faster than the usual coagulation in the free volume. A doze of coagulant at water clarification in contact clarifiers is smaller than in the course of two-stage treatment. The temperature of the water has almost no influence on the process of contact coagulation.

Key words

disinfection , surface water source , water supply plant , contact clarifier , loading material