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Objectives To investigate the sanitary condition of the secondary water supply for passenger trains in the administration area, to evaluate the influencing factors of the secondary water supply system for passenger trains, and to put forward suggestions for improving the water quality of the secondary water supply for passenger trains. Methods The water quality of secondary water supply of 48 trains of 24 pairs of CRH type passenger trains and 160 trains of 10 pairs of type 22 passenger trains and 30 pairs of type 25 passenger trains in Lanzhou Railway Bureau in 2019 was analyzed and compared. Results The qualification rate of 208 samples tested was 73.08%. The qualification rate of secondary water supply quality of type 22 and 25 passenger trains was 62.50% and 66.67%, respectively, and the difference was not statistically significant（χ2=0.23 ，P＞0.05）. The qualification rate of secondary water supply of CRH passenger train was 97.92%, which was statistically significantly different compared with that of type 22 and 25 passenger trains（χ2=18.40, 18.15, P2=0.056, 0.054, 0.056, 0.22, 0, and 0.22, P>0.05). The total number of bacterial colonies, total coliform, turbidity and iron in the secondary water supply of type 22 and 25 passenger trains did not meet the standard, while only one water sample for the secondary water supply of CRH passenger trains did not meet the standard. Conclusion The quality of secondary water supply of CRH passenger train is obviously better than that of type 22 and 25 passenger trains. Changing the position of defecation port and water injection pipe of type 22 and 25 passenger trains, selecting non direct train defecation collection system, or adding appropriate amount of chlorine disinfectant into the water supply hose can significantly improve the qualification rate of bacteriological indexes of secondary water supply of passenger trains.
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[Objective] To investigate the quality of secondary water supply in Shanghai , in order to provide the basis for efficient management measures . [ Methods] Secondary water supply data were collected and analyzed from Shanghai drinking water health inspection and monitoring information system . [ Results] Cleaning and disinfection of secondary water supply facilities and water quality self -check and others were found to be low in pass rate .The drinking water quality of secondary water supply was lower . The main unqualified monitoring indexes were oxygen consumption , total number of bacteria and residual chlorine. [ Conclusion] Several problems exist in secondary water supply .By using Shanghai drinking water health inspection and monitoring information system , we can take effective measures to achieve sec-ondary water supply scientific supervision , then ensuring water safety .
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Objective To konw the Legionella contamination in the central air condition system and secondary water supply system in the public places of Jiangxi province. Methods 145 water samples were collected from the public places with central air conditioning system and secondary water supply system, in July to September in 2005-2006. Bacteria culture, hemagglutination test and duplex PCR test were used to identify Legionella. Results 15 Legionella strains was isolated from 145 samples, the positive rate was 10.34%, 7 Legionella strains was isolated from 78 samples of central air conditioning system, the positive rate was 8.97%, 8 Legionella strains was isolated from 57 samples of secondary water supply system,the positive rate was 14.04%. Conclusion It is necessary to strengthen the surveillance of Legionella in central air conditioning system and secondary water supply system.
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Objective To know the hygienic condition of different kinds of drinking water plants in Shanxi Province.Methods In 2007,422 water plants and 2 083 secondary water supply units were selected and the information and data that provided by all Sanitation Institute for Health Inspection and Supervision in Shanxi Province were analyzed.Results The hygienic conditions of city's municipal administration water supply systems were the best.Total qualified rate of water quality was 97.67%.The hygienic conditions of rural school's homemade water supply systems were the worst,the qualified rates of all items in the program were the lowest.Most of them had no any analyst and laboratory for water quality test.Only 10.2% of them had water disinfection facilities.Total qualified rate of water quality was 75.32%.In most of water plants,the lack of water quality test facilities and disinfection facilities was one important problem in drinking water safety.In addition,the lack of clean and disinfection in secondary water supply systems was another problem.Conclusion The hygienic conditions of drinking water plans are unsatisfactory and should be improved in Shanxi Province.
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Objective To know the cause for contamination of drinking water in a hotel. Methods Samples were taken from the reservoir 1 h, 14 h, 22 h and 33 h after contamination and the perceptible character, chemical and bacteriological test were done by using the methods in Analytical Methods for Water and Sanitary Standard for Drinking Water Quality(2001). Results The turbidity increased at 14 h after contamination and the highest level reached 3.82 NTU. The residual chlorine in tap water from the reservoir was less than 0.05 mg/L, the total count of bacteria was 940 cfu/ml, the total coliform bacteria was more than 1 600 MPN/100 ml and fecal coliforms was 130 MPN/100 ml. Conclusion The contamination of drinking water in the investigated hotel is caused by drinking water reservoir leakage, so more attention must be paid to the contamination of drinking water reservoir.
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To understand the characteristics and causes of the pollution accidents of municipal water distribution network and secondary water supply system.Data on the pollution accidents of municipal water distribution network and secondary water supply system having occurred in recent 20 years were collected and analyzed. The main pollution type of municipal water distribution network and secondary water supply system was biological pollution,the amount of which took 73.3% of the total accidents.The pollution accidents mainly occured in schools or colleges and residential buildings offered by some enterprises to their members and families with an occurrence rate of 11.7%,besides residential quarters,enterprises and institutions.The main links of pollution were observed in municipal water distribution system(51.7%)and water storage tanks high and low lying(43.3%).The main causes of pollution accidents were the leakage and breakage facilities and mislink between the water pipes and sewage pipes, which resulted in formation of negative pressure.Siphonage and sewage flowing backward,in addition the poor sanitary protection facilities polluted by sewage and rubbish. It was the top priorities to establish special legal system,to enhence the preventive sanitary inspection
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Objective To investigate the drinking water quality of secondary water supply in Tongzhou District, Beijing in order to establish a data monitoring management system. Methods The uniform questionnaires were used for the on-the-spot investigation at secondary water supply units in the whole district, which included secondary water supply facility situations, environmental sanitary conditions and health management and so on. At the same time, municipal water and secondary supply water were tested. Results 48 units of secondary water supply were investigated. In this investigation, the main systems of secondary water supply were the low water tank added frequency conversion pump(accounts for 77.1%) and the inverter constant pressure water supply system with negative pressure(accounts for 14.3%). According to the hygienic requirements, the unqualified rate of water tank structure, disinfection facility and water tank room were 81.0%, 73.3% and 87.3% respectively; besides, 39.6% of the units used the invalid hygienic licenses, 43.5% of the water managers had no health certificates, and 54.5% of the units had never cleaned their water tanks. The total qualification rate of the secondary water supply was 66.7%. The main items that were not up to the standard were ammonia-nitrogen, free chlorine, recognizable objects with naked eyes, total bacteria count and turbidity. For the different water material, the qualification rate showed a significant difference(P=0.023). Conclusion The drinking water quality of the secondary water supply is lower than before and the preventive hygiene supervision and evaluation is comparatively delayed in the investigated district.
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Objective To Cenderstand the sanitation status of secondary drinking water supply system of public places. Methoods The sanitation of secondary drinking water supply system was investigated by on_site survey method and the sanitary quality of water samples were determined. Results The over_standard rates contents of Fe and total coliformz of water samples of secondary water supply system significantly increased compared with the related levels of tap water of municipal water supply. The unqualified rate of free residual chorine of water sample from secondary water supply system reached 54.55%. Conclusions The equipments for secondary water supply were obsolete and unretional design. The sanitary quality of secondary water supply was also affected by geological structure easily.