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Number 7 / 2018
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UDC 574.632/635
Chesnokova S. M., Savel'ev O. V.
Study of the antibiotics effect on self-purification processes
of hydroecosystems
Summary
Based on literature data the role of hydrobionts of various ecologic groups in self-purification processes of aquatic ecosystems is considered alongside with the possible effect of antibiotics getting into surface water on hydrobionts. The results of studies of antibiotics effect on small crustaceans-filterers Daphnia magna Sr. by biotesting method and on nitrobacteria by laboratory modeling method with the use of river water are given. It is stated that the toxicity and hazard of the studied antibiotics for small crustaceans-filterers depend on the origin of antibiotics, their concentration in water and capacity to accumulate in small crustaceans’ organisms. Out of the studied antibiotics cefazolin was most toxic for daphnia, whereas ampicillin and ceftriaxon were less toxic. However these antibiotics are characterized by obvious capacity to accumulate in daphnia’s organism and can further cause downsizing of the population of these hydrobionts, distortion of self-purification from suspended solids and trophic structure of hydrobiocoenosis. In order to study the effect of antibiotics on nitrification process cefazolin and cefotaxime antibiotics were used at the concentrations of 1·10–9–1·10–8 mg/dm3. It is stated that the effect of these antibiotics depends on the concentration and origin of antibiotics. Cefazolin at the studied concentrations inhibits nitrification process. Cefotaxime at the concentration of 1·10–8 mg/dm3 slightly inhibits and at the concentration of 1·10–9 mg/dm3 inhibits nitrification process. The highest inhibiting effect of the studied antibiotics is observed on the 15th day of exposure; nitrification process enhancement with cefotaxime at the concentration of 1·10–8 mg/dm3 was registered within the interval of 6–12 days of exposure.
Key words
nitrification , biotesting , antibiotics , self-purification of a water body , hydrobionts-filterers , laboratory modeling
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UDC 628.1.03
Ponomarev A. P.
Aqueous extract of shungite mineral – a complexing agent
for microorganisms in aqueous solution purification
Summary
The presence of microbiological pollution has been one of the most important factors that determine drinking water quality. Among the variety of water purification technologies unique mineral – shungite that contains carbon in active form – fullerene has been widely used over recent years. Herewith the strengths of shungite including bactericidal one are associated with fullerenes in particular. It is known that fullerenes merge into water in minimum concentrations; whereas for their efficient extraction organic solvents are needed. The results of studies of the effect of aqueous shungite extract containing beside macro- and microelements ultramicroelements – lanthanoids on microorganisms in aqueous solutions with the purpose of disinfection are presented. Electron microscopic studies provided for determining dual character of the effect: complex formation of microorganism cells and evident signs of bacterial cell destruction. Microorganisms as part of aqueous complexes are removed by sedimentation, centrifuging or microfiltration. Through the example of nanobacteria and foot-and-mouth disease viruses and virions the process of complex formation shall be considered as concentration with possible further use of the given microorganisms for scientific studies. The main mechanism of complex formation is the presence of high-reactive lanthanoid cations that are trivalent positive under normal conditions in shungite aqueous solution. The phenomenon of selective coagulation of bacterial cells is due to the reaction of lanthanoid cation complex formation with nucleic acids of microorganisms. It is assumed that the reaction of nucleic acid with metals is carried out by phosphate groups.
Key words
microorganisms , complexing , lanthanoids , electron microscopy , shungite , aqueous solution
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УДК 628.16.094.3:66.074.371
FESENKO L. N., Tcherkesov A. Yu., Ignatenko S. I., Shchukin S. A.
Purification of hydrogen sulfide containing natural water
by iron-catalytic oxidation in a reactor with unltrafiltration separation
Summary
Currently purification of hydrogen sulfide containing water has been still a bottleneck in water treatment and demands advanced high-efficient technologies, equipment and plants providing for solving at the same time drinking and environmental aspects. The technology based on iron-catalytic oxidation of sulfides in the presence of atmospheric oxygen and combined with membrane treatment is proposed as an advanced technology of hydrogen sulfide removal from natural water. The data on practical testing the proposed technology in a laboratory unit is presented. Subsequent to the results of the experimental studies the area of the developed technology application in purification of hydrogen sulfide containing natural water is substantiated. The absence of accompanying hydrogen sulfide emission from the reactor in the process of water purification and environmental safety has been noted. Based on the obtained results the technology is considered for today as possible and essential. Herewith further study with investigations directed at determining the optimal process parameters is needed.
Key words
natural water , water treatment , hydrogen sulfide , iron-catalytic oxidation of sulfides , membrane separation
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UDC 628.16.067.3
Filatov A. I.
Analysis of the method of calculating high resistance drainage of rapid filters
Summary
The methods of calculating high resistance drainage distribution systems for rapid filters are considered. In the practice of designing filtration plants in Russia several approaches to the structural concept of drainages that provide for equilibrium distribution of wash water in area have been worked out. It is shown that the method proposed by VNII VODGEO is the most substantiated; therefore it seems advisable to restore the recommendations on the use of this method in the practice of designing filtration plants in the regulatory documents. The analysis of the practical use of different approaches to the most useful method of calculating high resistance drainages for rapid filters shows the need to take into account a whole complex of indicators in these calculations. The most important among them is the indicator of drainage open ratio as well as assumed values of original flow rate of wash water in collectors (channels) and branches that determine the value of recovered head.
Key words
rapid filter , drainage-distribution system , wash uniformity , drainage open ratio , backwash loss
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UDC 628.165:66.081.63
Chigaev I. G.
The use of nanofiltration in brackish water softening
Summary
The results of the experimental studies with real water are presented that showed the perspectiveness of using the purification technology based on polymer nanofiltration membranes in underground brackish water desalination as compared to reverse osmosis. The basic characteristics of nanofiltration membranes were studied. Possible concentrating of influent water by partial concentrate recycling was evaluated; the maximum salt concentrations in recycling water were determined. The studies on evaluating the effect of deposit formation on the basic membrane characteristics did not discover any noticeable permeability reduction; herewith the zones of intensive salt deposit formation on membranes were identified. It was determined that salt concentration in recycling water supplied on the membrane shall not exceed 42 mg-equ/l to obtain permeate with up to 6 mg-equ/l and for permeate with 2 mg-equ/l hardness the salt concentration shall not exceed 18 mg-equ/l. Influent water concentrating provides for the substantial reduction of discharged concentrate.
Key words
reverse osmosis , membranes , nanofiltration , desalination , underground brackish water , deposit formation
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UDC 628.14:614.842.628
Deryushev L. G., Deryusheva N. L., Frog B. N.
Calculation of the distance between fire hydrants
Summary
Water supply system supplies water not only for drinking and household use but also for fire fighting. Water for fire fighting is abstracted from the water distribution network through hydrants with the use of rubber-lined hoses of fire trucks. Fire hydrants are installed on the pipelines of the water distribution network so that to provide for supplying water from more than one point. Herewith sufficient number of fire hydrants in the water distribution network is identified not only by the conditions of fire extinguishing and minimization of material expenditures but also by the technical capacity of the vehicles and equipment. In order to meet these requirements it is reasonable to summarize the data according to the conditions of fire extinction of objects together with the hydropower characteristics of the applied vehicles and equipment. Reference and regulatory documents on fire fighting contain limited and sometimes conflicting information of this kind. It is important to choose and use correctly the regulated parameters of the fire safety system in the process of justification of design choices of water supply systems. There are known cases when design choices of supplying water for fire fighting are approved with low efficiency. The use of substantiated guidance materials can help in improving the efficiency of design choices in the process of developing water supply sources for fire fighting. The proposed method of calculating the distance between fire hydrants in outdoor water supply networks is based on the regulatory requirements to fire fighting in buildings and structures as well as on the general principles of hydraulic calculations of pipelines and power parameters of water supply systems.
Key words
water supply system , outdoor source of fire fighting water supply , outdoor networks , fire safety , hydrant , guidelines
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UDC 696.1
Stepanov Mikhail, Zakharov Iu. S.
Rehabilitation of house drainage systems with the use
of BRAWOLINER® flexible polymer liners
Summary
Replacement of house drainage systems in apartment buildings with the use traditional technologies encounters active opposition of the residents and is often eliminated. The reason lies in the necessary subsequent renovation of apartments at the owner’s cost. The use of flexible polymer liners provides for rehabilitating house drainage systems with minimum demolition works and high quality within a very short time. This requires beside the availability of process equipment and qualified personnel also shrewd planning and high-quality organizational and preparatory works with account of the specific features of each project. The factors influencing planning and cost of the works are as follows: number of apartments; number of storeys in the building; number of stand-pipes; number of offsets and abuttings; length of the drainage system (stand-pipes, abutting pipes); scope of performing works; labour costs; distance to the object; extra work to provide for the access to the pipeline; scope of plumbing work (if required).
Key words
water disposal system , rehabilitation , house drainage system , rehabilitation , flexible polymer liner
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UDC 628.27
Vasilyev V. M., Morozov G. V., Zhukov S. V.
Problems in sewer network operation and ways of their elimination
Summary
The main problems arising during the operation of sewer networks – blockages, network deterioration and odors are highlighted. The causes of their occurrence are considered and methods of their elimination are proposed. Under the conditions of Russia blockages are most likely to occur as a result of errors in design and erection. These are violation of the pipe turnout grade, pipe diameter mismatch, turnout grade fault because of soil movement, unsatisfactory state of sewer and pipeline failure. Design and erection errors and low cultural level of the users of the sewer system can lead to the emission of high concentrations of hydrogen sulfide. Any blockage in the sewerage system is accompanied by foul odor above ground that is explained by the emission of hydrogen sulfide. By using advanced computer aids it is possible to keep account of all the factors that affect the useful life of sewers. Systematization of the obtained data and its further use provide for extending the pipe life and reduce the expenditures for renovation and maintenance of sewers. The paper is written on the basis of designing and operating the sewer networks in Saint-Petersburg.
Key words
pipeline , odor , sewer , sewerage system , clogging , microbiologic corrosion , sewer network deterioration , soil failure
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UDC 628.2+532.54
Dezhina I. S., Orlov V. А.
Association between inner pipeline surface with the phenomenon of microturbulence at low liquid flows
Summary
The results of field-scale studies of developing the effect of microturbulence at low flows of liquid in a pipeline are presented. The possibility of increasing the pipeline transporting capacity with account of the current development of trenchless technologies and modified configuration of the inner surface of polymer pipes has been analyzed. The applicability of these studies for increasing the flow transporting capacity is denoted; the analogies to the demonstration of the natural phenomena of liquid flow transportation are set. The pipeline chute profile with artificial obstacles that create conditions for suspended solids breaking off and transfer is marked as the
most perspective one. The design of a special patented test-bench for studying by optical means the turbulence and liquid flow transporting capacity is described. The technique of working with the test-bench is presented; the types of working surfaces with options of artificial obstacle arrangements are described. Comprehensive pilot studies of microturbulence analysis, suspended solids removal and flow transporting capacity in open chutes with different texture of their inner surfaces were carried out with the use of optical means. The occurrence of microturbulence effect in the process of studies at different liquid flows was registered alongside with the increase of the efficiency of suspended solids transportation by liquid flow. The recommendations on the form and location of obstacles on the inner pipe chute surface are given.
Key words
polymer pipeline , liquid flow velocity , turbulence , trenchless technologies of renovation , transporting capacity , surface texture
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