Automation of the technological processes of wastewater treatment: case study of the Minsk wastewater treatment plant of UE Minskvodokanal

Summary

The experience of UE Minskvodokanal in developing and establishing of automated control systems for the technological process of wastewater treatment is presented using the example of several structures of the Minsk wastewater treatment plant. The goals and tasks performed by the automated process control systems at the plant are described. The structure and operating modes of the implemented systems are presented. The stages of the wastewater treatment process are considered in detail: screening, sand removing and processing, supplying and distributing air across sections of the aeration tanks. As part of the automation of the presented treatment stages, the general design of the automated process control system is described, the operating features, the objects used and automation modes are given. Special attention is paid to the need for simple and reliable control algorithms. The ultimate goal of upgrading the automated process control system of the Minsk wastewater treatment plant is the maximum degree of automation and supervisory control covering the entire technological chain of wastewater and sludge treatment based on the simple and reliable principles.

Key words

wastewater , screens , sand catchers , algorithm of control , SCADA-system , aeration tanks , automation of technological processes , work station

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

UDC 628.35:536.24
DOI 10.35776/VST.2024.04.08

Ambrosova G. T., Kruglikova Anastasiia, Rafal’skaia Tat’iana, Timofeev S. L.

Heat exchange processes in open wastewater treatment facilities

Summary

The paper dwells upon studying heat and mass transfer processes between waste liquid passing through open wastewater treatment complexes and the environment. Under the conditions of operating facilities heat and mass transfer results in the waste liquid temperature increase or decrease depending on the time of year; and that leads, provided other things equal, to a change in the quality of treatment. The possibility of using mathematical models for open wastewater structures that describe heat and mass transfer processes used in heating engineering is considered. The study was carried out by analyzing domestic and foreign sources on heat and mass transfer. Changes in the temperature of waste liquid in open facilities were determined by calculation for a specific facility and compared with actual measurement data at the same facility. During the study, items of heat loss and input were established for the winter and summer periods of the year in three open structures: primary settling tanks, aeration tanks and secondary settling tanks. A mathematical model has been tested that determines the change in the temperature of the waste liquid depending on the residence period in the structures. The method for calculating primary settling tanks, aeration tanks and secondary settling tanks has been improved that provides for accounting at the design stage of the treatment facilities of the changes in the temperature of waste liquid during treatment, which eliminates deterioration in the quality of waste water treatment at any time of the year.

Key words

heat-mass exchange , aeration tanks , heat loss and input , primary and secondary settling tanks , wastewater quality , temperature variation

UDC 628.35
DOI 10.35776/VST.2024.04.07

Bagaev Iurii, Kharkina O. V., Krasavin Grigorii, Gundyreva Tat’iana

Development of basic process solutions for the reconstruction
of wastewater treatment facilities in Novosibirsk

Summary

An example of process solutions for the reconstruction of existing wastewater treatment plants using increased concentration of activated sludge and acidification of primary sludge is given. It has been shown that achieving the required effluent quality (N–NH₄ = 1 mg/l, N–NO₃ = 9 mg/l, N–NO₂ = 0.1 mg/l, Р–РО₄ = 0.7 mg/l) during the reconstruction of the facilities, the implementation of nitrogen and phosphorus removal processes in existing aeration tanks, with the actual flow of incoming wastewater, is possible by increasing the concentration of activated sludge in the aeration tanks to 5.2 g/l, which requires the installation of tertiary treatment filters downstream sludge separation in the secondary settling tanks. The use of tertiary treatment facilities to remove suspended solids is determined in comparison with a more expensive construction of an additional biological treatment unit operating with medium doses of activated sludge. It is shown that the information and technical reference book ITS 10-2019 being a recommendation and not a mandatory document, allows for the use of filtration structures for effluent discharge into category B water bodies. The issues of the responsibility of the designers of basic process solutions for achieving the required effluent quality during the implementation of the project are considered for two cases: first – the main process solutions and the project is developed by one company; second – the main process solutions and the project are developed by different companies.

Key words

wastewater treatment , designing , best available techniques , biological removal of nitrogen and phosphorus , acidification , public wastewater disposal system , aeration tanks , reconstruction of wastewater treatment facilities