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Original article УДК 628
DOI: 10.21285/2227-2917-2017-3-71 -76
STUDY OF THE EFFECTIVENESS OF INTERNAL AND EXTERIOR WATER DISPOSAL SYSTEMS OF MICRODISTRICT "BEREZOVIY" OF THE CITY OF IRKUTSK
© D.V. Skiboa, V.G. Sudnikovichb
Irkutsk National Research Technical University, 83 Lermontov St., Irkutsk 664074, Russian Federation
Abstract. Purpose. This paper presents the analysis of the effectiveness of water disposal system of microdistrict "Berezoviy", located on the outskirts of Leninsky district of Irkutsk. Methods.Overview of method of research of the technical state of drainage network. Results. Ventilation of the water disposal system is the integral process for its effective and safe operation. The sewer vent valves are intended to perform the aeration function and are used on the corresponding basis. The sewer vent valves that are placed in unheated garrets of the houses in microdistrict "Berezoviy", which is located in Leninsky district of the city of Irkutsk, don't meet the statutory requirements. These sewer vent valves aren't competent enough. In the conditions of lack of technical justification to application these aeration devices are making the operational situation worse in general. lack of outflow of sewer gases from the water disposal system reduces its endurance and creates threats to the person while it operates. Unreasonable technical solutions at the construction stage and the violation of the rules of operation are the result of unstable operation and decrease of the operating capacity of the water disposal system. Conclusions. Reliability and durability - the inherent requirements of the disposal system.
Keywords: waste water, ventilation network, drainage, vent valve, drain system with non-vented riser operation
For citation: Skibo D.V., Sudnikovich V.G. Study of the effectiveness of internal and exterior water disposal systems of microdistrict "Berezoviy" of the city of Irkutsk. Izvestiya vuzov. Investitsii. Stroitel'stvo. Nedvizhimost' [Proceedings of Universities. Investment. Construction. Real estate], 2017, vol. 7, no. 3, pp. 71-76. DOI: 10.21285/2227-2917-2017-3-71-76
Introduction
Water disposal system represents engineering facilities set intended for intake, drawing off, treatment, disinfection and waste water discharge in a reservoir or permeable soil. The water disposal system's objects are residential, industrial, public, official and special buildings equipped with water supply and sanitation. Efficiency and durability of the water disposal system are resulting from regulatory compliance during its design, construction and operation.
Information and research methods
Microdistrict "Berezoviy" in the city of Irkutsk occupies 37 hectares and is built up with apartment blocks from two to nine floors with a total area of 87053 sq.m. The microdistrict infrastructure is completed. According to the official data provided by the facility manager the number of the registered residents in the district is 2240 people. The siteplan is represented in a figure 1.
Disposal of waste waters from housing development in the residence is carried out on incomplete separate system in on-site self-flowing household water disposal system which is 2599 m long. Domestic waste waters come in the self-flowing mode to the module sewer pumping station and further through forced-main transmissions to the city's sewer network. Network connection point is the head absorber down the Rosa Luxemburg's street. Later on the public sewer disposes waste waters on left-bank waste treatment facilities of the city of Irkutsk. The water disposal system of this microdistrict is made from two-layer polyethylene pipes KORSIS that are produced as per TU 2248-001-730117502005 with a diameter of 160 mm - 220,5 m / p; 200 mm - 1899 m / p; 315 mm - 479,5 m / p, with a general extension of 2599 m. The disposal system also consists of different soak pits that are made from concrete steel elements and closed by 123 cast-iron manholes.
a Denis V. Skibo, graduate student of Department of engineering communications and life support systems, e-mail: [email protected]
Скибо Денис Владимирович, магистрант кафедры инженерных коммуникаций и систем жизнеобеспечения, e-mail: [email protected]
bVera G. Sudnikovich, candidate of technical Sciences, associate Professor of engineering communications and life support systems, e-mail: [email protected]
Судникович Вера Геннадьевна, кандидат технических наук, доцент кафедры инженерных коммуникаций и систем жизнеобеспечения, e-mail: [email protected]
The hot water supply system in the microdistrict is executed by the closed concept: water from the water supply system comes to the water-heating points where it's heating and further supplying to a consumer.
Since the begging of operation in March, 2014 till January, 2017 the volume of water consumption in microdistrict "Berezoviy" according to Irkutsk Municipal Unitary Enterprise
Water consumption from
"Vodokanal" makes from 1307 m3 to 10242 m3 monthly. The complete data of water consumption is provided in Table 1.
Since the begging of operation of the water disposal system in microdistrict "Bere-zoviy" in March, 2014 numerous cases of a characteristic smell of fecal drains in a zone of soak pits have been revealed.
Table 1
2014 to January 2017, m3
In 2014 - - 1312 1406 1307 2904 2626 3057 4991 1337 2334 2433
In 2015 2497 2269 2506 6666 6719 6628 10242 7982 8097 3778 4285 3412
In 2016 7567 4093 3553 3390 2814 3126 4049 3680 4298 3332 3386 5658
In 2017 4958 - - - - - - - - - - -
During the winter time there are periodical smells in sanitary rooms on the top floors, where the sanitary devices with waste water collectors are placed.
The carried-out analysis results of executive documentation of the water disposal system of microdistrict "Berezoviy" shows that sites 55 - 56; 92 - 93; 116 - 90 of gravity pipelines are mounted with a counter bias.
During visual check of household sewage system existence of sewer aerators (the valve vacuum sewer) on the upper ends of the sewer stacks 0 - 110 mm and 0 - 50 mm has been revealed. These devices are installed on the sewer stacks that are removed in the roof
void of unheated garrets (Figure 2). According to the point "b" SP 17.13330.2011 "Roofs" the architectural complex and constructive decisions that were used for the roof of the houses in microdistrict "Berezoviy" (Figure 3), also the materials used as the covering that protect buildings from penetration of precipitations, exclude a possibility of its operation.
The results and the discussions
As to the item 6.9.1 SP 32.13330.2012 "Sewerage. External networks and constructions" (revised edition) and the items 8.2.15; 8.2.16; 8.2.17; 8.2.18; 8.2.20. SP 30.13330.2012 "Domestic water supply and plumbing systems" it is necessary to provide
ventilation of an external water disposal system through stacks of an internal sewerage which are attached to the highest points of pipelines. An exhaust part of a sewer stack should be brought upward through a roof or a combined airshaft of a building:
- from a flat unexploited and cattle roof
- 0,2 m;
- a cut of the combined air shaft -0,1 m, also it has to be removed from the opened windows and balconies not less than 4 m.
Fig. 2. Ventilation internal household sewer network
Fig. 3. General view of the buildings of microdistrict "Berezoviy"
The diameter of an exhaust part of a single stack has to be equal to the diameter of its waste part. In unheated garrets these pipelines should be heat-insulated. Installation in the
mouth of an exhaust part of a stack of barriers as deflectors (a wind vane, a simple cap, etc.) is forbidden.
The height of an exhaust part on the operated roofs has to be not less than 3 m, but at the same time the extract has to unite not less than 4 struts. If it's impossible to fulfill this condition then sewer stacks shouldn't be removed above the roof. In this case each stack has to terminate in the ventilation valve that is installed in the mouth of a stack over half of the floor where the most high-located devices and equipment are installed. Figure 3 "b".
According to the point "b" SP 40-107-2003 "Design, mounting and operation of systems of the internal sewerage from polypropylene pipes" (with the edition) the ventilating valve of not ventilated sewer stack (Figure 4) is set in the upper part of a stack and passes air only in one direction - in a stack that isn't removed above the roof of the building (Figure 5 "b").
Fig. 4. Vent valve (SP 40-107-2003): 1 - insert; 2 - air duct; 3 - body; 4 - damper; 5 - air vent;
6 - the sewer riser; a is the area of the air flow
Fig. 5. The actual location of vent valve (a) and regulatory arrangement of the ventilation valve (6): 1 - manhole; 2 - release of sewage; 3 - non-vented riser; 4 - vent valve;
5 - sanitary appliances
The aerator as the device works at the time of volley of water realizing air flow in the system, thus preventing traps being pulled due
to the created discharge. In the closed status the aerator superimposes pipeline section without allowing the sewer gases to quit.
The sewer vacuum valve (the aerator) mounted on the vertical sewer pipeline in the cold garret of a house (Figure 5 "a") isn't capable to fulfill the functions (aerations) during the winter time. As in the conditions of the negative air temperature in the roof void of the garret, the freezing problem of the formed condensate inside the device (SP 30.13330.2012, [1]) is possible. This can cause stick-slip of a diaphragm and lead to a total failure of the device in operation.
As a result of incorrect operation of the aeration device and limited exhaust ventilation of the external water disposal system can be:
- a characteristic unpleasant smell in the locations of soak pits;
- a failure of hydraulic locks on water intake devices of the upper floors of buildings with a sewer gases discharge in locations;
I
- an increase in concentration of sewer gases raises the probability of inflaming or explosion during a sewer system operation.
On the locations of the gravity pipelines with a counter bias the hydraulic mode is executed by full cross-section with the loss of the self-cleaning velocity, and the subroof providing air-gas exchange in the water disposal system is also superimposed (Figure 6 "a"). Such conditions negatively influence reliability and durability of the water disposal system [2-5]:
- decrease of intensity of the self-cleaning mode provokes a silting of pipelines with their subsequent obstruction;
- absence of the necessary mode of the exhaust ventilation leads to an increase in concentration of aggressive gases and development of corrosion processes.
i
■
/ i \
f-------i------\
a) 6)
Fig. 6. Full cross-section (a) and the work section is not complete (6):
S - the area of the living section
Conclusion
The mounted ventilating sewer valves (the aerators) on sewer stacks of the water disposal system of the microdistrict "Berezoviy", which is located in Leninsky district of the city of Irkutsk, don't meet the statutory requirements of SP 40-107-2003, SP 30.13330.2012 and SP 32.13330.2012.
At this conjuncture connected with the lack of technical justification to application these aeration devices are making worse the operational situation in general. The restriction of outflow of sewer gases from the water disposal system not only reduces its potential, but also creates threatsto the person while it operates.
In terms of the conducted research of the of water disposal system's of the microsdis-trict "Berezoviy" operability and the analysis of standard and executive documentation: SP 32.13330.2012, SP 17.13330.2011, SP 30.13330.2012, SP 40-107-2003, as-built drawing - in order to obey the standard requirements of SP 32.13330.2012 "Sewerage.
External networks and constructions", Revised edition of Construction Norms and Regulations 2.04.03-85 (edition N 1); SP 30.13330.2012 "Domestic water supply and plumbing systems", Revised edition of Construction Norms and Regulations 2.04.01-85* - it is recommended to provide the exhaust ventilation of the external water disposal system in the microdistrict "Berezoviy" of the city of Irkutsk. It should be provided through stacks of the internal sewerage of the buildings attached to the highest points of pipelines. The exhaust part of sewer stacks needs to be brought upward through the roof: from the cattle roof - 0,2 m, and it has to be removed from the opened windows and balconies not less than 4 m. The diameter of the exhaust part of a single stack has to be equal to the diameter of its waste part. In unheated garrets these pipelines should be heat-insulated. Installation in the mouth of the exhaust part of the stack of barriers as deflectors (a wind vane, a simple cap, etc.) is forbidden.
Contribution
Skibo D.V., Sudnikovich V.G. have equal author's rights. Skibo D.V. bears the responsibility for plagiarism.
Conflict of interests
The authors declare no conflict of interests regarding the publication of this article.
The article was received 28 April 2017
