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UDC 628.166.085
Vasiliak L. M., SMIRNOV A. D.
Potential use of ultrasound in water disinfection
Summary
Ultrasound has been used long enough in engineering and medicine for diagnostics, visualization of underwater objects, surface cleaning and other systems. Using ultrasonic disinfection as a main or additional technology is impractical because of the long exposure time, high energy consumption and lack of regulatory documents. To improve the efficiency of disinfection equipment the manufacturers suggest additional ultrasonic water treatment in combination with oxidizers and UV irradiation. The data on possible use of ultrasonics both as an additional disinfection method and method of improving the efficiency of traditional technology from the point of view of the concept of establishing numerous barriers during disinfection is presented. Different types of ultrasonic effect for using in water disinfection systems are considered. Ultrasound provides for the extremely low disinfection efficiency compared to other traditional technologies, therefore it is not used as an independent method. Ultrasonic water treatment improves the efficiency of oxidation technologies. Combined action of ultrasonics and UV irradiation does not have any synergistic effect. For natural water and effluent after treatment according to the operating standards the standard UV dosages are sufficient to ensure meeting the microbiological standards. Additional ultrasonic treatment is advisable under special conditions. Quartz sleeves can be well cleaned with mechanical systems and chemical wash which is used by all the world leading manufacturers. Due to the particular hazard of ultrasonic contact impact on humans the process of ultrasonic treatment shall completely eliminate such potential effect.
Key words
disinfection , ultraviolet , wastewater , natural water , water treatment , ultrasound , chlorination agent
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UDC 628.16.066.7
Volftrub L. I.
Upgrade of clarifiers at energy facilities with the use laminar modules
Summary
The need for upgrading clarifiers of obsolete and outmoded design is substantiated. The clarified water quality and capacity of these facilities do not meet the modern water treatment requirements which can be explained by the design and technological characteristics of these facilities. The suggested technical solutions aim at the elimination of such deficiencies as unstable turbulent mode of the suspension settling in a sufficiently high layer (1.5–2 m), low volume utilization factor of clarifiers, the lack of an efficiently operating flocculation chamber. The experience of introducing laminar modules in the water treatment sections of energy facilities is quoted. The upgrade of pretreatment facilities, production of clarified water with low suspended solids, iron and organics concentrations will provide for improving the technical and economic performance of the water treatment units and introducing advanced technologies at the subsequent water treatment stages.
Key words
natural water , membrane technology , clarifier , honeycomb module , pretreatment , laminar module
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UDC 628.166.085
Roumyantsev V. A., Kriukov L. N., NEFEDOVA E. D., Rybakin V. N.
Evaluation of ultrasonic cavitation effect on toxicogenic algae
Summary
In the «Russian Federation National System of Chemical and Biological Safety (2009–2014)» Federal Task Program it is noticed that in Russia lots and lots of pollutants are discharged annually into surface waters. As a result deleterious hydrobionts, blue-green algae Cyanophyta (cyanobacteria) in particular, started dominating in fresh water bodies. In the process of lysis of these prokaryotes cancerogenic microcystines and neurotropic saxitoxins are formed; whereas in the process of chlorination in water treatment significant amounts of toxic halomethanes are formed. Research workers of Limnology Institute of the Russian Academy of Sciences (St. Petersburg) are studying in detail the potential of using ultrasonic cavitation and ultrasonic irradiation in combination with coagulation/flocculation in water treatment. In the experimental studies water samples with algae: unicellular and multicellular green algae, Xantophyta, diatomite algae and blue-green algae were used. The algae were either cultivated in the laboratory or the relative samples were taken from the ponds and lakes of St. Petersburg. The toxicity of the water samples before and after ultrasonic treatment of algae was determined by the method of biotesting and biorecognition with the use of cladocerans Daphnia magna. The concentration of chlorophyll was determined according to 17.1.4.02-90 State Standard (GOST). It was found that under the effect of ultrasonic cavitation the destruction of blue-green algae and water detoxification occurred. The obtained results of evaluating the effect of ultrasonic cavitation on toxinogenic algae instill confidence in the viability of the given processing technology. Needless to say that the development of the relative ultrasonic devices of acceptable power consumption provides for extending the scope of using the method for weedy water treatment.
Key words
natural water , eutrophication , blue-green algae , cyanotoxins , microcystines , saxitoxins , ultrasonic cavitation
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UDC 628.16:62-278
Vergunov A. I.
Removal of organic compounds from natural water
in a biosorption-membrane unit
Summary
The results of experimental studies on the purification of natural water of the Don River in a biosorption-membrane reactor equipped with flat-plate microfiltration membranes are presented. The research aimed at investigating the efficiency of the biosorption-membrane reactor operating with natural water with the subsequent determination of the kinetic characteristics of the running biosorption process. As a result of processing the experimental results, the efficiency of removing not only the turbidity and color of water, but also organic substances that caused high permanganate index and COD, was specified. The temperature constant was determined that provided for calculating the specific rate of oxidation of organic pollutants for the winter and summer seasons of the year. Using the obtained constants, it is possible to perform a design calculation of a biosorption-membrane reactor to any degree of purification required.
Key words
natural water , microfiltration , domestic water supply , biosorption membrane reactor , specific oxidation rate
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