Key Sections Research & Development
 
R&D
Research & Development Section
           
Research & Development Section of the NWSDB is under the Development Section headed by Additional General Manager (Policy & Planning).
           
Address Research & Development Section           Tel: +94 11 2625196    
  Telawala Road           Fax: +94 11 2607238    
  Ratmalana           E-mail agmrnd@waterboard.lk    
Vision  
Mission

Exploit local expertise and material as far as possible to succeed with application oriented research activities. 

 
Identify and implement economic means of providing potable water to people of Sri Lanka while minimizing environmental pollution.
           
Activities carried out during the year 2009
           
Developed a sand sieving machine
An electrically driven sand sieving machine was developed to get the required grading of sand by changing the sieve sizes. The constant sieving action of the machine produces better quality sand than manual sieving.  
           
A training programme was organized for the chemists on “Nuisance algae in water supply projects in Sri Lanka” in collaboration with Department of Zoology, University of Sri Jayewardenepura.  This training which focused on enhancing the knowledge in identification and enumeration of Algae in different water sources is very appropriate in solving the emerging algae related problems in the dry zone. Two identification studies “Algae removal efficiency of Microstrainer at Polonnaruwa” and “Algae identification study at Labugama and Kalatuwawa storage tanks” were completed.  
           
Removal of Hardness & Alkalinity of Water Treatment Plant  Puttalam
Several problems were identified in the treatment process of the Puttalam water supply scheme. One filter out of two cannot be operated due to hardening of green sand originally used for filter media. The problem was identfied as deposition of Calcium Carbonate in the filters due to excess alkalinity present in raw water. High Iron and manganese concentrations in the ranges 1.5 to 0.8 mg/L respectively in raw water is also a problem.

A model plant has been designed to carry out the softening process. Calcium Hydroxide is used as the softening agent to remove hardness by sedimentation step with subsequent Hydrochloric acid addition to adjust the pH in clarified water. Due to the high pH required for the softening process, the iron and manganese get oxidized and removed during the subsequent rapid sand filtration step. This softning and pH correction processes are being experimented in a pilot plant at site.
           
Study on Gravel Flocculation
The present two types of flocculators (Baffle & Mechanical)  need  space and hence are expensive. Inorder to develop low cost option, gravel flocculators are being tried especially in developing countries for small plants. As this is relatively different approach, an experimental setup based on filter columns received under JICA assistance is implemented to confirm the outcome.  The experiment is being conducted by changing the size of the gravel & the raw water flow rate to optimize the output variables.
           
Study on Pebble matrix filter at Kataragama
The infrastructure has been completed under the Work Bank funds. The objective was to achive 80to 90 percent removal of turbidity without chemical use by using Pebble Matrix Filter concept. The filters could not provide expected result due to some cracks identified at the filter nozzle deck and the pebbles not being of same expected size of 50 mm. Considering the difficulty in finding the pebbles and specially pebbles of same size for this work it is proposed to do further model testing with artificial filter media, namely burnt clay balls.
           
Evaluation of Performance against the Design Parameters of the Unit Process of the Konduwattuwana Water treatment Plant and Recommending Immediate Performance Improvements

As Konduwatuwan Tank water treatment system had developed some treatment problems creating unacceptable treated water quality in sporadic manner, a research study was initiated to evaluate the performance of all the unit treatment processes against the design parameters. Effciency and necessity of pretreatment steps, oxidation and adsorption on coagulaton & flocculation process and subsequent filtration step are studied in detail. The final outcome would be to propose how to improve the present treatment process.   The study comprised of  identification of the impact of pre treatment process on the Dissolved Air Floation (DAF) unit process with respect to manganese, algae and related organics removal. Identification of algae, their enumeration and assessing the toxin levels developed due to blue green algae within the treatment process were also covered in this study.   
           
Improving the performance of unit process of water treatment plants where the Irrigation Tanks are used as the source considering the Eastern Coastal Towns of Ampara District as a case study.

A trend of increased counts of algae and high concentrations of Manganese are noted in irrigation tanks of Sri Lanka. This is a threat to safety and acceptablility of tanks as source of safe water for drinking. As some of the already designed unit opeartion systems of treatment facilities of Ampara water supply scheme are having problems, a research project was initiated to study these treatment process problem and to recommend improvements to the unit operation modules to be implemented in future treatment plant designs for similar raw waters. This study focuses on the effect of pretreatment techniques such as oxidation and adsorption on the efficiency of coagulation flocculation process.   Chlorination and powdered activated carbon are the selected oxidant and adsorbant in this study. Fate of manganese and algal toxins in the treatement system are specially considered in this study.

           
Investigation of Contamination of Pesticide Residues and Toxic Metals in Water Reservoirs used for Water Supply and Treated Water in North Central Provinmce(NCP)

Emerging spread of diseases such as chronic renal failure in the NCP and the suspected reservoir pollution due to agricultural activity created the need for this kind of research study to establish the safety of such water for drinking even after conventional treatment. A pilot research study was proposed and commenced for the Nuwarawewa. This study has been focused to analyze the trace toxic metals and persistent organic pollutants such as pesticides in waters of irrigation reservoirs in North Central province in Sri Lanka.

           
Study on contamination sources of the Bomuru-Ella Reservoir at Nuwara-eliya

The study identified the pollution source of Bomuruella Reservoir which feeds Uma Oya. This water is used for drinking by several villages Ambagasduwa, Lunuwatta, Welimada, Uva Paranagama and Keppetipola downstream.  Identifed pollution sources are leachate from Moonplains landfill, vegitable washing, waste water discharges etc. It is concluded that a high organic pollution level prevails in the reservoir and at present the natural decay within the oya is reducing it to the Sri Lanka drinking water standard value at Ambagasduwa intake. There is no serious pollution due to heavy metals detected in the reservoir.  Finally it is recommended to implement catchment preservation program to mitigate pollution of this valuable surface water source especially caused by human activities.

           
Rainwater Monitoring Programme
Study was done to assess the quality of rain water for drinking and the results revealed that all water parameters are upto the Sri Lanka drinking quality standards  with pH in the range 6.5 to 6.8. The main drawback is high coli form levels which could be removed at domestic level by boiling, chlorination or bio sand filtration. 
           
Progress of work at the end of the year:
  • Developed a sand sieving machine - completed
  • A training programme on algae enumeration  subsequent to “Preliminary investigation of species composition of phytoplanton in raw and treated water in Labugama and Kalatuwawa Reservoirs” - completed.
  • Puttalam Water Supply Scheme water softning pilot study - In progresses
  • Study on Gravel Flocculation - In Progresses
  • Study on Pebble matrix filter at Kataragama - In Progresses
  •  Algae related study-Four sessions of sampling have been completed in the studies of Eastern Coastal Towns of Ampara District water supply scheme.
  • Contamination of storage tanks of North Central Province - First sampling has been carried out in Nuwarawewa in mid July of year 2009.
  • Study on contamination sources of the Bomuru-Ella Reservoir at Nuwara-eliya - Study completed and the final report to be submitted
  • Rainwater Monitoring Programme - In progress
           
::: Updated on 2010.09.15 :::
           
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