Scan Water Field Training Report

Transcription

1 Scan Water Field Training Report Bangladesh Trainers from Scan Water: Mr. Stein Midtlund and Mr. Jon Arild Holte Trainers from WHO: Mr. Tauficul Arif

2 SUMMARY As a response to the typhoon SIDR which struck Bangladesh November 2007 the Norwegian Government donated through WHO Bangladesh, four drinking water purification plants, household drinking water filters, jerry cans for carrying water and 1000 L tanks for water storage. Included in the donation was also training in Bangladesh by two persons from the supplier of the equipment, Scan Water in Norway. The purpose of the training was to teach local Bangladesh staff in the use of especially the Scan Water purification units, but also how to use the other equipment. The training was successfully conducted at four sites in the area affected by SIDR in Bangladesh between and All sites were connected to health centers In both Morrelganj and Mathbaria a thorough training session was held over two days at each site. From Morrelganj a smaller group from the training installed the system independently and got training in Sarankhola for one day. From the training in Mathbaria the same procedure was followed in Pathargata. The trainers from Scan Water introduced the system, the principles of water treatment and how to operate the system, and how to use the other equipment. During training Mr Tauficul Arif from WHO translated and explained details in Bangla for the participants.

3 Mr. Arif translating and explaining details of the system in Bangla Mr Stein Midtlund gives an introduction to the water filters

4 Summary of the main themes of the training - In short by bullet points Water treatment Why use chemicals, the process of flocculation The function of the sand filter and the Activated carbon filter The importance of disinfection Choice of chemicals Testing for finding most suitable chemical tablets for flocculation Testing the efficacy of different chemical tablets to clarify pond water

5 Filtration, Rinse and Back wash of sand filter How to operate the sand filter multivalve When to Backwash and how to rinse the filters The importance of chlorinating the filters before long term storage, and how to drain the filters before storage. Pictures above: Learning how to operate the multivalve and how to do the back wash, rinse and filtration procedures

6 Water quality Testing turbidity: what is turbidity and how to use he turbidity tube. Emphasizing that the turbidity should be at least as a minimum below 15 NTU. Guideline value is 5 NTU or less. Testing ph of the water using the color comparator Course participant using a turbidity tube to measure turbidity

7 Chlorination Use of the provided Calcium hypochlorite slow dissolving tablets Use of local Sodium hypochlorite by batch chlorination in Storage tanks Testing Chlorine residual levels with color comparator after 30 minutes storage. Residual chlorine should be between 0,2-0,5 mg/l. The locally available chlorine: Liquid Sodium Hypochlorite 5,25%. Water intake How to install and secure the water intake The non return valve Priming suction hoses Installing the strainer basket and securing the water intake with wooden sticks.

8 Operation and maintenance of the diesel engine and pump: Priming the pump and the suction hoses to get suction Starting and stopping the motor pump, when and how to change oil-,air- and diesel filters. General explanation on other spare parts, and maintenance Learning how to operate the diesel pump Maintenance of sand and carbon filter. How to and when to change sand and carbon in the filters. Flush filters with a strong 20 mg/l solution of Chlorine for 15 minutes before long term storage. Personal safety Handling chlorine: Chlorine chamber should never be opened during operation or when the system is under pressure. Calcium hypochlorite is a strong oxidizing agent and must be handled carefully. It should never come in contact with the skin or eyes.

9 To the right: Showing the procedure for cleaning the filter of the emergency drinking water kit. To the left: Assembling tap stand. To the right: Assembling 1000L storage tank.

10 General comments after field visit. Selection of water source for the water systems. Choosing the right water source is very important to achieve the best possible drinking water. It should always be taken into consideration possible contamination points. It would definitely be preferred to use water sources that is not contaminated by animals/livestock and ex. Swimming and bathing. Before choosing a source of water local people should be consulted to get a picture of how the source is used. The turbidity of the water source and the ph should also be tested before deciding where to install the system. ph of water ponds As we were told adding lime to water ponds has been part of restoring water quality in many of the water ponds in the SIDR affected areas. The lime raises the ph of the Ponds. We don t know the natural ph levels of the ponds. On general the ph in the ponds used during training had quite high ph levels. In all ponds the ph was above 8,2. (Our color comparator test kit stops at that ph level) High ph makes effective chlorination more challenging as the effectiveness of chlorination declines with increasing ph. When adding Chlorine to water the desired product of the hydrolysis is hypochlorous acid, which is effective against bacteria. The ph of the water source determines whether the hydrolysis leaves hypochlorite ion, which is a weak oxidizing agent, or if hypochlorous acid is produced. At ph 8,2 very little hypochlorous acid is available and consequently the disinfection will be poor. The time for disinfection will be longer and the amount of chlorine

11 needed bigger to provide an appropriate amount of hypochlorite acid. Recommended ph for optimal disinfection in the field should not be higher than 7,8. In conventional water treatment ph is adjusted along the production line for optimal disinfection and to deliver treated water within an ideal ph. In the field this is not possible and choosing the right water source therefore becomes even more important. High ph also influences the flocculation processes. Utilising local Sodium hypochlorite On arrival and during training we were asked if it was possible to use liquid Sodium hypochlorite solution to chlorinate the treated water. The system is delivered with Calsium hypochlorite slow dissolving tablets, and the dosing chamber on the purification unit is especially designed for these. Liquid solution must under no circumstance be used in the dosing chamber. In-line dosing is only possible with slow dissolving tablets. However adding chlorine solution to bulk treated water at the storage point is of course no problem. This was practiced at the training. Local 5,25 % liquid sodium hypochlorite was added to the treated water in the provided 1000L storage tank. The chlorinated water must be stored for minimum 30 minutes before distribution. Scan Water is these days developing a in line liguid dosing module for our customers. Environmental protection At one of the sites it became necessary to drain some of the oil from the motor pump. From this work there was a considerable oil spill. The pump is almost always placed near the water source, and maintenance work that will obviously lead to oil spill should be done away from the water source to protect it. One drop of oil pollutes huge amounts of water.

12 The instruction manuals Both manuals, the field and the more thorough operation and field manual, contain the information needed to install and use the purification systems. We recommend that at least one responsible person for each system read these manuals thoroughly. This person should be available at the site were the system is going to be used. The manuals contain all the information given on the training, and also give many valuable hints for use and operation under emergencies. Finding the right chemical composistion(tablets) to achieve good flocculation This operation is probably the most difficult and needs patience. It is the composistion of the water and its physical/chemical characteristics that determines which tablets that will give the best results. At the training we experienced that it was very easy to find the right composistion and also quite difficult in one of the ponds. It must be emphasized that this work is given guidance in the instruction manual, but from time to time quite some time of experimenting is required to find the best solution which consumes the least possible amount of tablets. We advise this work to be done by a skilled person who is capable of understanding the simplest principles of water characteristics. After our visit in Bangladesh we have decided to improve our chapter on how to use the tablets.

13 Final comments The training in Bangladesh went very smoothly. WHO had gathered skilled people to the seminar. Some of them we expect to have more leading roles when the treatment systems are in operation. We were taken very good care of by Mr. Arif and his assistants. We feel that the training went well and that the training itself were valuable. The trainees should be able to operate the systems and also use the other equipment without any big problems. We wish to thank Mr Arif for his professionalism and for taking care of everything. Food,transport, accommodation etc. Thanks also to Dr Andrew and the other staff at WHO Bangladesh who facilitated our stay. Scan Water wish the receivers of the equipment good luck and hopefully the donation from Norwegian government will secure safe water for many people in the aftermath of SIDR and also in the future when needed. Please do not hesitate to contact us if any problems, or any questions. Kind regards Stein Midtlund and Jon Arild Holte CONTACTS: Stein Midtlund Sales Manager Phone : Mail : stein.midtlund@scan-water.com Jon Arild Holte Customer support Phone: Mail : jon.arild.holte@scan-water.com Scandinavian Water Technology AS Kvernhusvn. 21 P.O.BOX HARESTUA Norway Mail: sales@scan-water.com Web: Phone Fax