WS/T 528-2016Specification for small centralized water disinfection (English PDF)

4.1 Basic principles of disinfection

4.1.1 The water quality of the water source to be disinfected should meet the requirements of Chapter 5 in GB 5749-2006.

4.1.2 Water treatment facilities include coagulation sedimentation tanks, filter tanks, clean water tanks and disinfection equipment. In addition to ensuring the water treatment facilities required for disinfection Adjust other facilities according to the water quality of the water source.

4.1.3 Quality management should be strengthened for water treatment facilities, maintenance systems and operating procedures should be established, and regular cleaning and disinfection should be carried out.

4.1.4 Small-scale centralized water supply should be disinfected. The disinfection method should be safe and effective. Production equipment and containers should be corrosion-resistant.

Non-toxic and non-irritating to operators.

4.1.5 Among the raw materials used, sodium chlorite should meet the requirements of GB/T 1618, sodium chlorite should meet the requirements of HG 3250, and sodium chloride should Meet the requirements of GB 2721.Hydrochloric acid should meet the requirements of GB 320, sulfuric acid should meet the requirements of GB/T 534, and citric acid should meet the requirements of GB 1987 Requirement; sodium bisulfate should be food grade, purity should be >=98%. The raw materials of calcium hypochlorite disinfectant should not contain ingredients such as washing and decontamination.

4.1.6 The disinfectant and disinfection equipment used should comply with relevant national standards, norms and regulations, and should not pollute drinking water.

There are monitoring records and kept for future reference.

4.1.7 After disinfection, the microbiological indicators, disinfectant balance, disinfection by-products and other water quality indicators of the factory water shall comply with GB 5749-2006 Requirements in 4.1.7.

4.1.8 The storage room of disinfectants and raw materials should be strictly prohibited from smoking, keep the room dry, cool and ventilated. Do a good job of storage, raw materials can not be mixed be careful when placing, handling or moving.

4.2 Requirements for effect evaluation

4.2.1 Before the replacement of disinfection methods, before the new (reconstruction, expansion) small centralized water supply unit water supply, when microbial water pollution incidents occur, in the event of an infectious disease or natural disaster emergency, when the disinfection equipment has been continuously stopped for more than half a year, the laboratory disinfection effect should be evaluated and Health and safety evaluation.

4.2.2 The frequency of free residual chlorine and residual chlorine dioxide inspection is once a day, and the intensity of ultraviolet radiation and the residual ozone can be tested regularly.

4.3 Hygienic requirements for personnel directly engaged in disinfection operations

4.3.1 It shall be trained in drinking water and disinfection related laws and regulations, obtain a certificate of hygiene knowledge training, and master the disinfection operation procedures.

4.3.2 Obtain a health certificate. Suffering from active tuberculosis, viral hepatitis A, viral hepatitis E, enteric infectious disease, chemical Persons with purulent or chronic exudative skin diseases and hand fungal infections should not engage in disinfection operations until they are cured.

5.1 Chlorine dioxide disinfectant generator

5.1.1 Installation and operation requirements

5.1.1.1 The working environment temperature of chlorine dioxide disinfectant generator is 5°C~40°C, and the relative humidity should be <=90%.

5.1.1.2 The chlorine dioxide disinfectant generator should be placed in an independent disinfection room, and its use space should meet the operation and safety requirements. Disinfection room Water, electricity, mechanical ventilation, personal protection and accident emergency facilities should be provided, as well as drainage measures.

5.1.1.3 The output pipeline of the chlorine dioxide disinfectant generator should not leak.

5.1.1.4 The chlorine dioxide disinfectant should be added by jet, and the jet effect of the jet should be adjusted according to the pipe diameter and pressure.

Chlorine dioxide disinfectant should be added at the entrance of the clean water tank, and the dosage should be variable dosage according to the water quality and water volume changes.

5.1.1.5 The feed pump of the chlorine dioxide disinfectant generator should start and stop consistent with the water source pump (or valve). The main material or activator is lacking, and the jet is stopped when abnormal conditions such as transportation occur, the chlorine dioxide disinfectant generator should immediately alarm and stop automatically.

5.1.2 Disinfection operation method

5.1.2.1 In accordance with the requirements of the product instruction manual, check that the chlorine dioxide disinfectant generator should operate normally.

5.1.2.2 If the electrolytic chlorine dioxide disinfectant generator is used, the sodium chloride and the drinking water shall be mixed and dissolved according to the ratio of the instruction manual.

Solution, put it directly into the storage tank (tank), turn on the power, start the work switch, the chlorine dioxide disinfectant generator starts to work, and set the storage tank the liquid in the (tank) is pumped into the electrolytic cell, and the water is continuously disinfected. If you use a chemical chlorine dioxide disinfectant generator, combine the main ingredients with the drinking water is mixed and dissolved according to the ratio of the instruction manual, filtered, and then added to the main material storage tank (tank), and the activator is added to the activator storage in the liquid tank (tank), turn on the power, start the work switch, the chlorine dioxide disinfectant generator starts to work, and put the main material storage tank (tank), the solution in the chemical agent storage tank (tank) is pumped into the reactor according to the prescribed amount.

The main materials of the chemical chlorine dioxide disinfectant generator include sodium chlorate, sodium chlorite, sodium chloride; the activator includes hydrochloric acid, sulfuric acid, lime Citric acid, solid citric acid should be used after diluting into a solution according to the instructions.

5.1.2.3 Adjust the flow rate of the metering pump for variable dosing according to the changes in water quality and water volume, and continuously disinfect the water. The contact time with water should be >=30min, the limit of chlorine dioxide in the factory water should be 0.8mg/L, and the balance should be >=0.1㎎/L.

5.1.2.4 After disinfection, turn off the working power supply.

5.1.2.5 The disinfection operation should also meet the specific requirements of the product instructions for use.

5.1.3 Matters needing attention

5.1.3.1 Strictly follow the product instruction manual for regular maintenance and maintenance. The chlorine dioxide disinfectant generator should be unplugged during maintenance and repair.

Source plug.

5.1.3.2 Check the sealing condition of the system regularly, and deal with it immediately if there is any leakage.

5.1.3.3 Add raw materials in time.

5.1.3.4 The chlorine dioxide disinfectant should be used immediately.

5.1.3.5 The feeding system equipment, host reactor and pipe fittings shall be cleaned regularly.

5.1.3.6 If the chemical chlorine dioxide disinfectant generator is used for disinfection, the main material and the activator should not be mixed and stored. The chlorine dioxide disinfectant If the generator is not used for a long time, the metering pump and the reactor should be cleaned thoroughly before storage.

5.1.3.7 For disinfection by electrolytic chlorine dioxide disinfectant generator, it should be pre-run for 12 hours before first use.

5.1.3.8 The outlet of the electrolytic cell should be equipped with an exhaust pipe to discharge hydrogen to the outside. The exhaust should avoid contact with the power source and be far away from fire.

5.2 UV sterilizer

5.2.1 Installation and operation requirements

5.2.1.1 The working conditions of the ultraviolet sterilizer should meet the requirements in 6.1 of GB 28235-2011.

5.2.1.2 Turbidity of influent water quality <=5NTU, total iron content <=0.3mg/L, color <=15 degrees, water temperature >=5°C, total coliforms <=1000 A/L, the total number of bacterial colonies <=.2000 CFU/mL.

5.2.1.3 The UV sterilizer of the corresponding specification should be selected according to the water quality and the maximum daily water supply.

5.2.1.4 Install the ultraviolet sterilizer on the water supply pipeline at the outlet of the clean water tank, and the water supply pipeline should not leak.

5.2.1.5 A space for replacing the ultraviolet germicidal lamp should be reserved on the side of the ultraviolet sterilizer.

5.2.1.6 Bypass pipelines and shut-off valves for maintenance and repair of ultraviolet sterilizers shall be provided.

5.2.1.7 Inlet water pressure <= 0.6MPa.

5.2.2 Disinfection operation method

5.2.2.1 In accordance with the requirements of the product instruction manual, check that the ultraviolet sterilizer should be able to operate normally.

5.2.2.2 Turn on the power, open the water inlet valve of the ultraviolet sterilizer, start the work switch, the ultraviolet sterilizer starts to work, and continuously Disinfect.

5.2.2.3 Determine the water flow speed according to the radiation intensity. The ultraviolet radiation dose of the new ultraviolet lamp tube should be >=12000µW·S/cm2.

The ultraviolet radiation dose of the UV lamp tube should be >=9000µW·S/cm2, and the thickness of the water layer should be less than 2cm.

5.2.2.4 After disinfection, close the water inlet valve, and then turn off the power supply.

5.2.2.5 The disinfection operation should also meet the specific requirements of the product instructions for use.

5.2.3 Matters needing attention

5.2.3.1 When the cumulative use time of the ultraviolet germicidal lamp time meter shows that it exceeds the effective life specified in the product manual, it should be replaced in time Light tube.

5.2.3.2 The radiation intensity of the lamp can be measured by using the ultraviolet intensity irradiation indicator card or the ultraviolet radiation illuminance meter.

5.2.3.3 The UV sterilizer should be maintained by professionals.

5.3 Ozone generator

5.3.1 Installation and operation requirements

5.3.1.1 The working environment temperature of the ozone generator is 5°C~40°C, the relative humidity should be <=80%, the atmospheric pressure is 86 kPa~106 kPa, cold but the water temperature is < 35°C.

5.3.1.2 The ozone generator should be placed in an independent disinfection room, and its use space should meet the operational requirements. The disinfection room should be supplied with water, electricity, and Equipped with mechanical ventilation, personal protection and accident emergency facilities, and drainage measures.

5.3.1.3 A mixing device for ozone gas and water should be installed.

5.3.1.4 The ozone water dosing point should be set on the water supply pipeline at the entrance of the clean water tank, and the ozone generator output pipeline should not leak.

5.3.2 Disinfection operation method

5.3.2.1 In accordance with the requirements of the product instruction manual, check that the ozone generator should be able to operate normally.

5.3.2.2 Turn on the power, open the ozone generator cooling water valve, then open the air source valve, start the work switch, and the ozone generator starts jobs.

5.3.2.3 Adjust the flow rate of the air/oxygen gas source flow meter according to the water quality and water volume to do variable feeding, and continuously disinfect the water.

The water contact time should be >=12min, and the ozone limit in the factory water should be <=0.3mg/L.

5.3.2.4 After disinfection, turn off the power.

5.3.2.5 The disinfection operation should also meet the specific requirements of the product instructions for use.

5.3.3 Matters needing attention

5.3.3.1 The electrical safety of the ozone generator shall meet the requirements of 6.2.2 in GB 28232-2011.

5.3.3.2 The pipeline is complete and reliable to ensure that the cooling water system and air source system can work normally and there is no leakage.

5.3.3.3 Ozone should be used and occurred.

5.3.3.4 When the concentration of tail gas ozone exceeds the allowable concentration in the environment, it is not allowed to be directly discharged into the air. Can be discharged through exhaust gas treatment or recycled back Use technology to solve. The concentration of ozone emitted after treatment is specified to be <=0.16mg/m3.

5.4 Sodium hypochlorite generator

5.4.1 Installation and operation requirements

5.4.1.1 The operating power supply voltage of the sodium hypochlorite generator is 380V±38V.

5.4.1.2 The installation of sodium hypochlorite generator shall meet the requirements of 5.2 in GB 28233-2011.

5.4.1.3 The sodium hypochlorite generator should be placed in an independent disinfection room, and its use space should meet the operational requirements. The disinfection room should be supplied with water and electricity, Equipped with mechanical ventilation, personal protection and accident emergency facilities, and drainage measures.

5.4.1.4 The dosing point of sodium hypochlorite disinfectant should be set at the entrance of the clean water tank.

5.4.1.5 The metering pump for adding sodium hypochlorite disinfectant should start and stop consistent with the water source pump.

5.4.2 Disinfection operation method

5.4.2.1 In accordance with the requirements of the product manual, check that the sodium hypochlorite generator should be able to operate normally.

5.4.2.2 Dissolve sodium chloride in drinking water according to the proportion of the product specification, and prepare it into a raw salt water with a concentration of 30g/L~50g/L.

Materials, stored in a storage tank (tank).

5.4.2.3 Add sodium hypochlorite to the sodium chloride solution after the storage tank (tank) is fully dissolved according to the method and volume specified in the product instruction manual Inside the generator electrolyzer.

5.4.2.4 Turn on the power supply, start the work switch, the sodium hypochlorite generator starts to work, and electrolysis is carried out in accordance with the procedures specified in the instruction manual.

Put the prepared stock solution of sodium hypochlorite disinfectant into a storage tank (tank), the content of lead (Pb) should be <=0.05mg/L, and the content of copper (Cu) should be <=1.0mg/L, the content of cadmium (Cd) should be <=0.01mg/L.

5.4.2.5 Sodium hypochlorite disinfectant should be added at the entrance of the clean water tank, and the flow rate of the metering pump should be adjusted according to the water quality and water volume.

Plus, the water should be disinfected continuously, the contact time with water should be >=30min, and the free residual chlorine limit in the factory water after disinfection should be 4mg/L, the amount should be >=0.3㎎/L.

5.4.2.6 After disinfection, turn off the power.

5.4.2.7 The disinfection operation should also meet the specific requirements of the product instructions for use.

5.4.3 Matters needing attention

5.4.3.1 During the electrolysis process, cooling of the sodium chloride solution should not be interrupted.

5.4.3.2 The outlet of the electrolyzer should be equipped with an exhaust pipe to discharge the hydrogen outside. The exhaust should avoid contact with the power source and be far away from the fire source.

5.4.3.3 When the sodium hypochlorite generator is running, the fluctuation of the electrolytic voltage beyond the rated value shall be adjusted in time.

5.4.3.4 The power cabinet and generator in the sodium hypochlorite generator should be equipped with effective grounding devices.

5.4.3.5 The electrolyzer of the sodium hypochlorite generator shall be acid washed regularly.

5.4.3.6 When the effective chlorine content of the generated sodium hypochlorite disinfectant is less than 10% of the specified content, the equipment should be terminated or the electrode should be replaced.

5.4.3.7 Sodium hypochlorite disinfectant should be used now, and the storage time of sodium hypochlorite disinfectant before use after occurrence should not exceed 24h.

5.5 Calcium hypochlorite disinfectant

5.5.1 Conditions of use and installation requirements

5.5.1.1 The disinfectant should have a dedicated storage room, which should be dry and well ventilated.

5.5.1.2 Calcium hypochlorite disinfectant shall meet the requirements of "Technical Specification for Hygienic Quality of Bleaching Powder and Bleaching Powder Disinfectant" (2010 edition).

5.5.1.3 There should be disinfectant residual detection equipment.

5.5.1.4 If the automatic dosing method is adopted, the automatic dosing device shall be installed first; if the manual dosing method is adopted, there shall be a device for preparing and dissolving the disinfectant.

Tools, containers, tools and containers should be made of corrosion-resistant and easy-to-clean materials.

5.5.1.5 The automatic dosing device should be placed in an independent sterilization room, and its use space should meet the operation and safety requirements. The disinfection room should be filled with water, it is electrified, equipped with mechanical ventilation, personal protection and accident emergency facilities, and has drainage measures.

5.5.2 Operation method of automatic dosing and disinfection

5.5.2.1 In accordance with the requirements of the product manual, check that the automatic dosing device can meet the normal operation.

5.5.2.2 Add calcium hypochlorite disinfectant into the storage box of the automatic dosing device according to the amount specified in the product instruction manual.

5.5.2.3 Turn on the power, start the work switch, and the calcium hypochlorite automatic dosing device starts to work. Adjust measurement according to water quality and water volume changes the flow rate of the pump is variable and the water is continuously disinfected. The contact time with water should be >=30min. Free residual chlorine in the factory water after disinfection the limit should be 4mg/L, and the margin should be >=0.3㎎/L.

5.5.2.4 Calcium hypochlorite disinfectant should be added at the entrance of the clean water tank.

5.5.2.5 After disinfection, turn off the working power supply.

5.5.2.6 The disinfection operation should also meet the specific requirements of the product instructions for use.

5.5.3 Manual dosing and disinfection operation method

5.5.3.1 Calculate the amount of calcium hypochlorite disinfectant needed according to the water volume of the clean water tank, weigh it and set it aside.

5.5.3.2 Mix and dissolve calcium hypochlorite disinfectant and drinking water according to the ratio of the instruction manual. If it is a non-instant tablet, it should be researched first.

Grind into powder.

5.5.3.3 Calcium hypochlorite disinfectant should be directly added at the entrance of the clean water tank and mixed evenly. The dosing process should be based on the water quality and water volume changes.

Variable dosage, the contact time with water should be >=30 min, the limit of free residual chlorine in the factory water after disinfection should be 4 mg/L, and the remaining amount should be >=0.3 ㎎/L.

5.5.3.4 The disinfection operation should also meet the specific requirements of the product instructions for use.

5.5.4 Precautions

5.5.4.1 Calcium hypochlorite disinfectant should not be mixed with other disinfectants, alkalis or organic substances.

5.5.4.2 Calcium hypochlorite disinfectant should be used and prepared.

5.5.4.3 The calcium hypochlorite disinfectant should be disinfected with an automatic dosing device. The disinfectant added automatically should not be an effervescent tablet.

The device should not pollute the water quality.

5.5.4.4 The automatic dosing device shall be regularly maintained and maintained in accordance with the instruction manual, and the plug shall be unplugged during maintenance and repair.

5.5.4.5 When performing disinfection operations, wear gloves; if you accidentally contact your eyes, ...