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UDC 628.35:661.5
Nikolaev Yu. A., KOZLOV M. N., Gavrilin A. M., Kevbrina M. V., Pimenov N. V., Dorofeev A. G., Agarev Anton, Kallistova A. Iu.
Innovative energy efficient and resource-saving technology of removing ammonium from wastewater under anaerobic-anoxic conditions
Summary
The specialists of «Mosvodokanal» JSC have developed the technologies of ammonium oxidation under anoxic conditions: double-reactor for low temperatures and single-reactor for 30–37 °С. The technology for the operation at 10–25 °С is performed by bacteria (discovered in «Mosvodokanal» JSC) Сandidatus Аnammoxomicrobium moscowii, fixed to the bed. The rate of nitrogen removal is 50 g/(m3·day) of the reactor. The technology for warm wastewater treatment is performed by new bacteria Сandidatus Jettenia moscovienalis, fixed to the bed; the rate of nitrogen removal is 0.47 kg/(m3·day). The use of continuous flow and fixed feed increases the output of the reactor to 0.8 kg/(m3·day). Considering the high economic attractiveness and efficiency of the technology it could be expected that in the very near future the technology will become a frequent practice in wastewater treatment. For the development of the industrial-scale technology a grant was awarded within the frames of the Federal special-purpose program «Research and development for the priority orientations of the development of the scientific and technology sector in Russia for 2014–2020». The work is carried out in cooperation with Federal Research Centre «Fundamentals of Biotechnology» of the Russian Academy of Sciences in Vinogradskii Institute of Microbiology business unit. A pilot plant with a 20 m3 reactor has been assembled, commissioned and operated at the Liuberetskie wastewater treatment facilities in Moscow of a treatment capacity of 20 m3/day of dewatering centrifuges filtrate.
Key words
sedimentation tank , wastewater , surplus active silt , sludge , Anammox , ammonium oxidation
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UDC 628.169
Kofman V. Ya.
Enhancement of biogas generation during anaerobic digestion of excess activated sludge (a review)
Summary
In the process of biological wastewater treatment vast amounts of sludge are generated. Among the methods of sludge handling anaerobic digestion holds a prominent place combining both possible biogas production and prevention of secondary environmental pollution. The rate-limiting stage of anaerobic digestion is hydrolysis. Sludge pretreatment is a common way to increase the rate of hydrolysis and enhance biogas production; developing pretreatment options has been an area of noticeable exploratory activity. Methods of chemical pretreatment (acidic, alkaline, electrochemical oxidation, ozonation, Fenton process, persulfate process, treatment with calcium peroxide), biological pretreatment (two-stage thermophilic/mesophilic process) and physical pretreatment (thermal hydrolysis, microwave treatment, electrokinetic disintegration, ultrasonic treatment, high pressure homogenization) are considered. The patented technologies for pretreatment of wastewater sludge and the main manufacturers of the relative equipment are presented. As an alternative to the traditional anaerobic digestion a microbial electrolysis cell is considered where methane generation during electromethanogenesis occurs in the presence of exoelectrogenic bacteria. A number of wastewater sludge pretreatment technologies are currently available for the implementation on an industrial scale. In this regard, an urgent need in the development of a standardized methodology for analyzing the technical and economic indicators of various anaerobic digestion systems is evident in order to select an optimal option for specific conditions.
Key words
surplus active silt , anaerobic fermentation , thermal hydrolysis , pretreatment , acidic treatment , alkaline treatment , electrochemical treatment , Fenton process , persulfate process , microbial electrolysis cell , electrokinetic disintegration , ultrasonic treatment , homogenization , microwave treatment
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DOI 10.35776/VST.2021.08.05
UDC 628.35
Zoubov M. G., Vilson Elena, Obukhov Dmitrii
Method of combined treatment of air terminal wastewater and liquid wastes from dry closets of aircrafts
Summary
The composition of the wastewater of air terminals includes sewage and industrial wastewater from the technological equipment of the food unit. Process flow schemes for wastewater treatment of air terminals do not provide for the reception and treatment of liquid wastes from water closets of aircrafts, that are highly concentrated in terms of COD, ammonium nitrogen, phosphorus. In addition, they contain high concentrations of disinfectants with quaternary ammonium salts (QAS) as an active ingredient toxic to microorganisms. As a result of liquid waste discharge to the operating treatment facilities of the air terminal, the quality indicators of biological wastewater treatment have significantly deteriorated, and the properties of the biocenosis of the biofilm have also changed. The aim of the research was to determine a method for reducing the concentration of QAS to the level where the toxic effect on the biofilm biocenosis ceased, and to develop an appropriate process flow scheme. An analysis of the literature data on the impact of QAS on activated sludge microorganisms is presented; on this basis laboratory studies were carried out and a method was developed for the pre-treatment of liquid waste from aircraft water closets for the subsequent combined treatment with the air terminal sewage. In the course of the tests, the efficiency of pollution sorption, including QAS, by the preliminary regenerated excess activated sludge was determined. The technological parameters of the processes were determined; an efficient, reliable, easy-to-use process flow scheme for the combined treatment of sewage of the air terminal and liquid waste of water closets of aircrafts was developed and implemented.
Key words
biological treatment , surplus active silt , adsorption , air terminal wastewater , liquid waste of water closets of aircrafts , quaternary ammonium salts , pre-treatment
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DOI 10.35776/VST.2022.01.08
UDC 628.355:543.635.355:504.7
Kofman V. Ya.
Upcoming trends of processing waste activated sludge.
Preparation of volatile fatty acids (a review)
Summary
Among the methods of obtaining products with higher added value from waste activated sludge, produced avoiding the emission of greenhouse gases, anaerobic digestion is considered as a viable alternative to biogas production to obtain volatile fatty acids as the final product, that are an intermediate product of methane production in the traditional process. The main factors affecting the production of volatile fatty acids are considered, including pH value, temperature, C/N ratio, process duration, organic matter load of the fermenter, and the presence of microelements. An effective way of increasing the yield of volatile fatty acids is the combined digestion of waste activated sludge and substrates with a high organic carbon concentration (food waste, corn stover, manure, wastewater from dairy and pulp-and-paper production, filtrate from solid waste landfills), as well as pretreatment methods: physical (ultrasonic, microwave, thermal), chemical (alkaline treatment, free nitrous acid, metallic iron, peroxomonosulfate, etc.) and biological (biological surfactants, hydrolytic enzymes, hydrolytic bacteria) ones. The main fields of application of volatile fatty acids are presented including the preparation of medium-chain fatty acids, the production of polyhydroxyalkanoates, protein of single-cell organisms, electricity, hydrogen, as well as the use as a carbon source in the process of biological nitrogen removal.
Key words
surplus active silt , anaerobic fermentation , electric power , volatile fatty acids , polyhydroxyalkanoates , protein of unicellular organisms , medium-chain fatty acids , hydrogen , additional carbon source
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UDC 628.336.429:504.009
KERIN A. S., Sidorov S. M., Sokolova E. V.
The Use of the UGOS-110Installation in Technological Processes of Wastewater Sludge Treatment
Summary
Results of the study of possibility of using the UGOS-110 installation for enhancement of efficiency of excess activated sludge in the flow charts of domestic wastewater treatment are described. Non-densifying activated sludge from the secondary settling plants was treated. As a result it is established that the use of UGOS-110 equipment is the most preferred at facilities of biological treatment of domestic wastewater with output of up to 3000 m³ per day. It makes it possible to improve the level of sludge dewatering, reduce the flocculant consumption, cut equipment costs.
Key words
wastewater , biological treatment , surplus active silt , dehydration , flocculant , sludge moisture content , compaction
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DOI 10.35776/MNP.2020.01.07
UDC 628.316.12:546.1:665.753.4
Kofman V. Ya.
Development of promising methods of wastewater treatment with energy recuperation in China and India (a review)
Summary
In China, active research is underway for developing a technology for excess activated sludge fermentation to obtain hydrogen. The process of anaerobic fermentation includes three main stages: hydrolysis, formation of hydrogen and acids, and methane generation. At the hydrolysis stage, the formation of low-molecular substances from high-molecular starch, fibers and proteins. At the stage of the hydrogen and acids formation hydrogenogenic and acetogenic bacteria ensure the fermentation of low-molecular substances with the formation of a number of organic acids, hydrogen and carbon dioxide. At the stage of methane generation, methanogenic bacteria metabolize the products formed in the previous stages with the release of methane and carbon dioxide. As a result, hydrogen can be obtained only by inhibiting the activity of methanogenic bacteria eliminating the impact on the activity of hydrogenogenic bacteria. Considering these circumstances methods are being developed to enhance the production of biohydrogen. The main efforts in this area aim at finding strains with high efficiency of anaerobic fermentation. Another direction is choosing a method of activated sludge pre-treatment from among thermal, acid, alkaline, microwave treatment, sterilization and ultrasonic treatment. Significant prospects are associated with the use of a consortium of microorganisms and mixed substrate containing, along with wastewater sludge, food waste, straw or manure. In India, the technologies of processing various types of industrial wastewater with the production of biomass enriched with lipids for the subsequent production of biodiesel have been on the march. The studies have been performed using Rhodococcus opacus bacteria, Rhodosporidium kratochvilovae yeast and Desmodesmus sp microalgae.
Key words
wastewater , surplus active silt , biodiesel fuel , biohydrogen , anaerobic fermentation , hydrogeonogenic bacteria , Rhodococcus opacus bacteria , Rhodosporidium kratochvilovae yeast , Desmodesmus sp. microalgae , intracellular lipid accumulation
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UDC 628.32
DOI 10.35776/VST.2023.11.08
Kichigin V. I., Iudin Aleksandr
Experimental and statistical models of the water yielding capacity of thickened excess activated sludge treated with chemicals
Summary
The technology of changing the specific resistance of excess activated sludge taken from the sludge thickener at the municipal wastewater treatment facilities was tested by processing the sludge with aluminum sulfate and polyacrylamide (PAA) with doses from 0 to 300 mg/dm3. The degree of impact of each chemical on the degree of sludge dewatering was defined. It was shown that PAA had a greater effect on the water yielding capacity compared to Al2(SO4)3 by 4.4 times with the chemical doses from 0 to 200 mg/dm3 and 2.2 times with the doses from 100 to 300 mg/dm3. Mathematical dependences of the change in the sludge specific resistance on the amount of Al2(SO4)3 and PAA added were obtained. The mathematical models are also presented in graphical form (isolines). The optimal doses of coagulant and flocculant for the chemical treatment of the wastewater sludge under study were determined.
Key words
surplus active silt , sludge specific resistance , mathematical and graphical models of the sludge water yielding capacity , optimal dose of chemicals
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