| 4. In which ways is the initiative creative and innovative?
In 1997, WATER QUALITY DEPARTMENT developed booster chlorination station at Laadkrabang pumping station. Disinfectant used was liquid chlorine (100 Kg. cylinders), confronted to various barriers and finally the booster chlorination station at Laadkrabang pumping station was concluded as un-successful.
To set up booster chlorination station in order to improve water quality in distribution network need to consider various factors as the experiences of MWA in setting up Laadkrabang booster chlorination station in 1997.
Liquid chlorine is not good to be used as disinfectant at booster chlorination station due to safety concerns, community concerns and high toxic concerns.
The concerns on quality of disinfectant to be used in the booster chlorination system, how to check quality, percentage, maintaining stock, maintaining continuous feeding with proper dosage.
The concerns on high labor cost, 24 hours services feeding
Automatic Booster Chlorination Station at Bangplee pumping station has almost solved all this concerns.
Automatic Booster Chlorination Station at Bangplee pumping station is
• An Absolute automatic system, no man operation system, 100% depend on machine and equipment
• Disinfectant used in the system is sodium hypochlorite 10%
• Disinfectant storage tanks capacity 24 cubic meter which could be used for more than 10 days
• Ultrasonic level measurement to measure amount of disinfectant stock with high accuracy of 3 digit
• Disinfectant stock can be monitored real time and record hourly
• Chemical metering pump, digital controlled and adjustable by PLC (Programmable Logical Control),
• A reserve chemical metering pump for emergency or maintenance
• Make use of inlet water flow meter (already existing at Bangplee pumping station), monitoring, recording
• Using info from # 8 in formula calculation of disinfectant dosage making proportional to inlet flow of water to the system
• Make use of free chlorine residual value retrieved from Real-time Tap Water Quality Monitoring System at Bangplee pumping station, monitoring, recording
• Using info from # 10 in formula calculation and control (adjust +/- in percentage) of set up chlorine dosage
• Digital Flow Meter for monitoring Real time information of disinfectant flow rate and record hourly
• CCTV record and monitor physical appearance and safety concerns
• CCTV can be accessed in intranet of MWA
Automatic booster chlorination can be accessed and controlled on web based application
This system was developed by using the existing communication network of Real-time Tap Water Quality Monitoring System, which used ADSL VPN
Data recorded at the site at data logger and at WATER QUALITY DEPARTMENT server
SMS service warning to 10 mobile telephone in 10 cases of designed incidents such as power failure, low/high free Chlorine residual, Low level of disinfectant stock, etc
The Automatic Booster Chlorination Station at Bangplee pumping station was approved by the director of Water Quality Department of MWA for trial for 6 months in 2009.
In Jan-Apr 2008, free chlorine residual at Bangplee pumping station was rather low, determined in monthly average of 0.08-0.16 mg/l. (free chlorine residual WHO recommendation at pumping station ≥0.50 mg/l)
In May 2009, Water Quality Department installed “Automatic Booster Chlorination Station” at Bangplee Pumping station and feeding sodium hypochlorite 10% at the average dosage of 0.6 mg/l. This could rise up free chlorine residual to 0.24-0.41 mg/l. during May-Dec 2009 to the desire level of as recommended by WHO.
| 5. Who implemented the initiative and what is the size of the population affected by this initiative?
Stakeholders involved in the implementation can be classified as follows:
MWA staffs work together, including scientists, IT experts, water treatment engineers, pumping station operators, senior management, chemical suppliers, laboratory technicians and private suppliers of automatic chlorine feeding equipment.
| 6. How was the strategy implemented and what resources were mobilized?
In the first 6-months trial period, MWA put an investment of 650,000 Thai Baht to run the Automatic Booster Chlorination Station at Bangplee pumping station. The trial set did not include the building cost.
The trial was done base on the experiment of trial and if the conclusion was positive the permanent unit could be then considered.
| 7. Who were the stakeholders involved in the design of the initiative and in its implementation?
The service area of Bangplee pumping station is very far distance from Bangkhen water treatment plant, about 30 km. It take about 18-20 hours for treated water to travel from TR3 transmission station at Bangkhen water treatment plant to pass through the 3rd route of MWA tunnel to Bangplee pumping station.
Since 2006, Bangplee pumping station first started its capacity at 180,000 CMD. After the completion of 3rd route of MWA tunnel in October 2009, Bangplee pumping station increased it capacity to 330,000 CMD
MWA, Water Quality Department installed “Real-time Tap Water Quality Monitoring System” at Bangplee pumping station in July 2008.The system assists scientists to monitor water quality in 2 main parameters, turbidity and free chlorine residual.
The Automatic Booster Chlorination Station at Bangplee pumping station could show with clear outputs as
-Decreasing of amount of disinfectant by-products formation
-Decreasing of chlorine usage in the system.
Whereas the priorities concerning to booster chlorination station of how to feed proper chlorine dosage to water distribution network is also solved by the system.
Booster chlorination would lead to lower the concentration of chlorine residual in water distribution network when compare to traditional chlorination at water treatment plant. That means amount of disinfectant by-products formation will be reduced too.
This would also lead to the better distribution of chlorine residual in water distribution network too.
This would improve water quality in the distribution network and increase the efficiency in controlling the re-growth of bacteria and reduce THMs formation.
The complaint in odor and taste of water in distribution network from location near to water treatment plant will be also reduced.
In the view of economic, in calculation of chlorine usage in the system, booster chlorination will be reduced total amount of chlorine usage in the system compare to the traditional chlorination at water treatment plant.
Experience at Bangplee pumping station, where MWA set up booster chlorination station in 2009. This could be reduced amount of free chlorine residual at TR3 from 2.0 mg/l to 1.4 mg/l) and amount of water is 1,000,000 CMD. That means this could reduce amount of chlorine usage for 6,000 Kg/day.
In environmental aspect, using less chemical not only benefit to an economic aspect but also gain carbon credit too.
| 8. What were the most successful outputs and why was the initiative effective?
The Automatic Booster Chlorination Station has continued for four phases, each phase has increased the workload as follows:
• Phase 1 (2010):the permanent Automatic Booster Chlorination Station was installed at the Bang Plee pumping station.
• Phase 2 (2011 - 2012): Two more stations were installed at Min Buri and Lad Krabang Pumping stations.
• Phase 3 (2012 - 2013):Three Automatic Booster Chlorination Stations were at LatPhrao, Samrong and Khlong Toei pumping station.
• Phase 4 (2014): MWA plans to install the system at three more stations including Phetkasem, Ratburana and ThaPhra pumping.
The remaining service areas gain water directly from water treatment plants.
The system was real-time monitored by scientists and technicians through the water quality monitoring system plus periodic field sampling by MWA water quality scientists. Contour Free Residual Chlorine contour was also mapping on monthly basis to evaluate the amount of free residual chlorine in tap water.
These could ensure the reduction of health related risk of MWA tap water.
| 9. What were the main obstacles encountered and how were they overcome?
Problems mainly occurred due to:
1. Chemicals procurement system. Due to the continuous installation of the automatic chlorine feeding system to cover the service area and expected increasing usage of chemical each year, then chemical procurement plan was revised in order to spare the liquid chlorine for each pumping station and for emergencies.
2. Technologies and communication systems. We often encountered problems using PLC (Programmable Logic Controller) which caused by intermittent power (surges) hence the installation of additional surge protection equipment is in priority. Furthermore, there is a problem with backup servers and reporting systems. All of these need trained specialists to operate.
3. Staff rotation can cause disruption in the operation. The work manual and knowledge management is one of the solutions.