Revisiting the selection of wastewater disinfection technology

Summary

Environmental law enforcement in relation to discharging chlorine and organochlorine contaminants induces the use of advanced safe and efficient chlorine free methods of wastewater disinfection. The use of ultraviolet irradiation provides for meeting all the requirements imposed on the technology of wastewater disinfection eliminating any adverse impact on the environment. The use of this technology eliminates possible penalty charges for polluting the environment with chlorine and organochlorine contaminants. The economic comparison of two disinfection methods (the application of sodium hypochlorite and UV-irradiation) reveals significant operational benefit when introducing UV-disinfection. Annual savings of operational expenditures is 50% and more at the comparable capital expenditures. The advantages of UV-disinfection are as follows: efficiency in relation to all types of indicator and pathogenic microorganisms, whereas chlorine-containing chemicals do not often ensure fair efficiency in viruses and protozoa elimination; no by-products are generated; no adverse impact on the water bodies is produced (consequently, no penalties); no threat of overdosing; easy and simple control over the disinfection process; no need in dosing system and additional control systems; disinfection effect independence from fluctuations of effluents quality within the limits of the design parameters; minimum footprint; no additional facilities are needed (e. g., contact tank for dechlorination); possible retrofitting into the existing buildings or facilities, for example, in the process of wastewater treatment facilities upgrade and chlorination replacement; low operational expenditures (lamp replacing once in a year and a half – two years and energy saving). In this context switching to chlorine free disinfection technologies that eliminate the formation of organochlorine contaminants is a correct solution.

Key words

chlorination , disinfection , wastewater , dechlorination , ultraviolet irradiation , effluents charge

UDC 628.2/.4:006.3:349.6
DOI 10.35776/VST.2023.02.02

Danilovich Dmitrii, Frog Dmitrii

The main innovations introduced by Amendment No. 2 to the Code of Practice CP 32.13330.2018 «Sewerage. Pipelines and Wastewater Treatment Plants»

Summary

The main prerequisites for the development of Amendment No. 2 to CP 32.13330.2018, and the tasks facing this work are described. The main innovations introduced by Amendment No. 2 are considered. The principles of synchronization of the system of engineering regulation of wastewater treatment processes with environmental regulation of discharges; clarification of the provisions for determining the estimated wastewater inflows; additions to the subsection on drain stations are described. The main additions and clarifications in terms of wastewater and sludge treatment technologies are described and justified (Chapter 9 of the Code of Practice), namely: updated requirements for intrahour safety factors while calculating channels and flumes; supplemented requirements for reliability in the design of channels of bar screen buildings and the data for calculating the amount of screenings depending on bar spacing; specified conditions for the use of sewage regulators; requirements for the calculation of primary settling tanks, aeration tanks, secondary settling tanks; recommendations for the removal of phosphorus; requirements for the redundancy of sludge dewatering equipment in case of the lack of spare sludge beds; introduced formulas for calculating the pollution of primary effluent; recommendations for sludge acidification from primary settling tanks; requirements for the redundancy of submersible electromechanical equipment of aeration tanks and for the regulation of sludge discharge from secondary settling tanks; detailed recommendations on the use of filtration beds for receiving effluents; the limits of applying mandatory dechlorination while using chlorine and the allowability of using prefabricated units.

Key words

treatment facilities , sewerage , screens , phosphorus elimination , set of rules , dechlorination , primary and secondary settling tanks , pipelines and wastewater treatment plants , municipal (mixed) wastewater , estimated inflow , sewage regulators , drain stations , calculations , aeration tanks , equipment redundancy , sludge acidification , filtration beds , prefabricated units

bbk 000000

UDC 628.166.085

Kostyuchenko S. V., SMIRNOV A. D., Tolstoi M. Iu.

Domestic technologies and equipment for chemical free treatment of water and wastewater of the Siberian cities and industries

Summary

The chemicals used in liquid and gaseous media treatment and purification either stay intact in the processed environment or disintegrate and react with the processed environment or admixtures in it and form numerous secondary and often toxic products. In this context chemical free methods of media purification aiming at their environmental safety are of most interest. Chemical free methods of treatment do not result in the formation of such a big amount of secondary products; whereas the efficiency of their use is often higher because they less depend on the type and structure of the targeted substance or admixture as well as on the conditions of use. Ultraviolet irradiation has been the most efficient and widely used method of chemical free disinfection of effluents both in Russia and abroad. The capital expenses for UV-disinfection are significantly reduced since there is no need in constructing contact tanks for chlorination and dechlorination; in addition the absence of chemical consumption eliminates the need in constructing a chemical plant and installing dosing systems. Using the example of the Siberian Region the advantages of using UV-irradiation in wastewater treatment is described.

Key words

ultra-violet irradiation , ecological safety , water disinfection , chlororganic compounds , residual chlorine , dechlorination , chemical free disinfection

bbk 000000

UDC 628.166

Tkachev Andrei, Baranov V. L., Piskareva V. M.

Comparative assessment of the operating expenditures for wastewater disinfection with the use of chlorination and UV-technology

Summary

Protection of drinking water sources has been the most important comprehensive task. The state of the surface water bodies is determined to a large extent by wastewater flow in them that should be epidemiologically safe according to the RF legislation. The use of ultraviolet irradiation has been the most environmentally and economically efficient disinfection method. To provide for the assessment of the economic efficiency of UV-disinfection technology five operating wastewater treatment facilities of different capacity were considered. The comparison of the annual operating expenditures for chlorination (exclusively of the expenditures for dechlorination and charge for chlorine and chrloorganic compounds discharge) and UV-irradiation was carried out. The studies showed that operating UV-disinfection units were more cost-effective compared to operating chlorination units at the treatment facilities of different capacity.

Key words

chlorination , disinfection , ultraviolet , wastewater , dechlorination , disinfection system operation , economic comparison

bbk 000000

UDC 628.166.085

Kostyuchenko S. V., Baranov V. L., Tkachev Andrei

Ultraviolet radiation – an advanced method of wastewater disinfection

Summary

The current regulatory requirements to effluent disinfection with chlorine agents demand an obligatory dechlorination stage. In the present context physical methods of wastewater disinfection can be an alternative solution. The method of wastewater ultraviolet radiation with the wave length of 253.7 m and low pressure amalgam lamps is most efficient and widely used. The given method is characterized by the high disinfection efficiency in relation to all types of microorganisms including viruses; by the absence of negative environmental impact; by the absence of disinfection by-products in wastewater, and equipment compactness. Engineering and economical comparison of the two methods of disinfection is presented: with the use of chlorine agent and ultraviolet radiation. It is shown that the method of ultraviolet radiation disinfection is more cost effective. The absolute value of the annual economic effect of using the equipment for UV disinfection of wastewater is increasing with the increase of the capacity of the facilities as a result of significant operational costs saving even at minor increase of the amount of the wastewater treated.

Key words

chlorination , disinfection , wastewater , ultra-violet irradiation , dechlorination , low pressure amalgam lamp

FaLang translation system by Faboba