1、(aim Manufacturing Standards DISINFECTION OF NEW OR CONTAMINATED WATER UTILITY INSTALLATIONS Desinfektion neuer oder verunreinigter Wasserversorgungs-Anlagen 1. SCOPE 1.1 The purpose of this Ford Manufacturing Standard is to specify those methods to be employed in the disinfection of new water utili
2、ty installa- tions, those being reconnected after being out of service for a long period and those installations which have become contaminated by micro- bial infection. This standard or national legislation, whichever is the more stringent, shall be applied. 1.2 Materials to be used in this applica
3、tion shall be from approved sources and the toxicological environmental control aspects evaluated considering local conditions in accordance with Manufacturing Procedure EU-II-d-l. 2. GENERAL 2.1 Recommendations relating to frequency of inspection and implementation of disinfection routines are deta
4、iled in Physical Asset Preservation Guide Line EU-AP-7 Preventive Maintenance of Water.Utility Service System. 2.2 The following routines shall be performed on all new installations prior to being taken into use for the first time as well as for disinfection for normal maintenance purposes. 3. REQUI
5、REMENTS 3.1 Pioinq 3.1.1 Piping shall be effectively cleansed and disinfected before being taken into use and in each occasion after being opened up for repair or alteration. 3.1.2 At the time of laying, pipes shall be brush cleaned and sprayed internally with a 5% solution of sodium hypochlorite. I
6、n the case of small bore pipes a polyurethane foam plug shall be inserted and passed through the bore. This may be done by inserting the foam plug at a hydrant and washing through to an end hydrant or open end. Wherever possible, pipes shall be capped at each end prior to connec- tion to prevent ing
7、ress of dirt. Mmfacturing Standards Office u-MSoc%8001 June. 1995 Water Utility Installations - Disinfection Page 1 of 3 Manufacturing Standards 3.1.3 In pipework under pressure, disinfection shall be carried out through a properly installed injection point at the beginning of the pipe- line, using
8、a chemical pump, until the free residual chlorine is evenly dispersed throughout the water and the concentration of chlorine measured at the end of the pipework is between 20-50 mg/l. The chlorinated solution shall be left in the system for not less than 24 hours and then the whole thoroughly flushe
9、d out with clean water until chlorine cannot be detected at a level above that present in the water undertakings clean supply. 3.1.4 Where junctions are inserted into an existing pipeline, the junction itself shall be cleaned and disinfected by immersion in a 5% solution of sodium hypochlorite befor
10、e insertion and the new pipel?ne from the junction treated as described above. 3.1-s The Water Authority shall be informed of the intention to disinfec parts of the pipework so that measures can be taken in order to protect drinking water against chemical pollution. 3.2 Installations within Buildina
11、s 3.2.1 The cistern shall be cleaned to remove all visible dirt and debris. The cistern and distributing pipes shall be filled with clean water and then drained until empty of all water again. Refill the cistern and when full close the supply and add a measured quantity of sodium hypochlorite soluti
12、on of known strength to the water in the cistern to give a chlorine concentration of 50 +/- 5 mg/l in the water. The cistern should be left to stand for one hour. Successively open each tap and fitting connected to each distributing pipe working progres- sively away from the cistern. Close each tap
13、or fitting when the water discharged has a chlorinous odour. Allow the cistern and pipes to remain charged for further one hour. Open the tap furthest from the cistern and measure the chlorine in the water discharged from the tap. If the concentration of chlorine is less than 30 I?, the disinfecting
14、 process shall be repeated. 3.2.2 Whenever practical, the cistern and pipes should remain charged with chlorinated water for at least 16 hours (overnight), then drained and thoroughly flushed with clean water until the chlorine concentration at the taps is no greater than that present in the clean w
15、ater supplied by the undertaking. Appropriate hazard warnings should be placed on the taps throughout the building. Ma&actu&gStanclardsOffice U-MSOO9-8001 June 19% Water Utility Installations - Disinfection Page2of 3 m =?lD=?1bD 0048424 84T - Manufacturing Standards 3.2.3 3.2.4 3.2.5 3.2.6 Note- Pro
16、prietary solutions of sodium hypochlorite should be used in accordance with the manufacturers instructions and MATS Data Sheets. A graduated plastic container should be used to measure out the volume of solution required for disinfection. This can be calculated from the manufacturers literature. A s
17、uitable proprietary test kit should be used for site measurements of residual chlorine. Hypochlo- rite is toxic, corrosive and a powerful oxidising agent. In some circumstances, the use of solid chlorine release tablets will be desirable. Chlorinated water that is run to waste in natural watercourse
18、 or a drain leading to same shall be dechlorinated or diluted in accordance with the requirements of the authority responsible for land drainage and pollution control. Discharge into sewers shall be with approval of the responsible authorities also. Dechlorination can be achieved using sodium thiosu
19、lphate. Note- 20 g of sodium thiosulphate crystals are required to dechlori- nate 500 li tres of water containing 20 mg/l free chlorine. The above procedure may be used to disinfect other water containing structures. However, it is important to check first that the mate- rials of construction are no
20、t subject to chemical attack by chlorine solutions and that proper provision has been made to discharge the chlorinated water and refill or flush through the structure with clean water. All temporary connections to pipework connected under mains pressure must incorporate adequate protection against
21、back siphonage. 4. OTHERMETHODS In some circumstances involving new or recommissioned installations, chlorine disinfection should not be employed. In many circumstances involving microbial contamination of installations, chlorine disinfection must not be employed. Consult Toxicology and ensure alternative biocide treatments are undertaken by an approved water treatment specialist. ManufacturingStandardsOfike u-m009-8001 June 19% Water Utility Installations - Disinfection _ Page 3 of 3
