Slow Sand Filtration

Transcription

1 Japan International Cooperation Agency Slow Sand Filtration JICA-Net Multi-Media Training Programme

2 Project Summary Name of the Project Establishment of Water Supply Management System in Kambia District Target Area Rokupr, Magbema Chiefdom, Kambia District, Period of the Project Counterpart December December 2008 Water Supply Division (WSD), the Ministry of Energy and Power The Government of Overall Goal Realization of sustainable and proper water supply service in Rokupr. Project Purpose Outputs Activities Establishment of water supply management system in Rokupr and supply of safe water to the residents. 1. Restoration of the function of Rokupr water supply facility. 2. Capacity development of the technical staffs of Rokupr water supply facility. 3. Establishment of tariff system of Rokupr water supply facility. 4. Capacity development of the administrative staffs of Rokupr water supply facility. 1.1 Site survey of Rokupr water supply facility. 1.2 Water quality analysis, topographic survey, survey of distribution network, etc. 1.3 Survey of construction material/equipment and capability of local contractors. 1.4 Preparation of a plan, design and tender documents for the rehabilitation of Rokupr water supply facility. 1.5 Tender for the rehabilitation work including P/Q, delivery of documents, Q&A, bidding and evaluation. 1.6 Rehabilitation of Rokupr water supply facility and the construction supervision. 1.7 C/P training for the above plan, design and construction. 2.1 Preparation of the O/M manual for the facility. 2.2 C/P and operator training/ojt for the above O/M manual. 3.1 Socioeconomic and household survey in the target area. 3.2 Preparation of a tariff system and a collection plan. 3.3 C/P training for the above tariff and the collection plan. 4.1 Preparation of the management manual for water supply including a financial analysis method. 4.2 C/P training for the above management manual JICA-Net

3 Inputs Japanese side 1. Experts: Short-term expert x 4 (28M/M) - Project Leader/Management of Water Supply Facility - Sub-Leader/Water Supply Management - Design and Supervise of Facility Construction - Maintenance of Water Supply Facility/Maintenance of Pipeline 2. Cost of rehabilitation of Rokupr water supply facility Sierra Leone side 1. C/P personnel (4 WSD engineers) 2. Cost of land acquisition for a slow sand filter 3. Cost of C/P personnel 4. Office and furniture, training/seminar venues Rokupr Approx. 14,000 Population Location of the Project JICA-Net マルチメディア教材 -2-

4 1. Background of the Project The Water Supply Division (WSD), which was a department of the Ministry of Energy and Power (MEP), has jurisdiction over rural water supply services in Sierra Leone and participated directly in the construction, operation and maintenance of water supply facilities until In particular in major rural towns (42 locations), water supply facilities equipped with flocculation and sedimentation or rapid sand filtration systems were planned and constructed in the 1970s and 1980s in cooperation of the World Bank or the Government of France. However, several years have elapsed since their construction and many facilities have become non-operational due to a lack of knowledge and skills in the above rapid sand filtration system and insufficient working capital. And to make matters worse, many facilities were destroyed during eleven years of the civil war. Although Rokupr water supply facility which was constructed between 1987 and 1989 through Japan s Grant Aid was also improved as a water supply facility equipped with a rapid sand filtration system in accordance with the standards for establishing water supply facilities at that time (treated river water was provided for small rural towns of greater than 2,000 people through public taps and house connections), as with other rural small towns, three years later the facility stopped functioning and damage sustained during the civil war. From the lessons learned in the past and the present state of water supply facilities in the above-mentioned rural towns, the policy of the Government of Sierra Leone toward future rural water facility management is not to adopt facilities requiring high skills in operation and maintenance. Although the Government of Sierra Leone has promoted the development of spring and stream water and dug wells which utilize hand pumps, under such the policy, it will be difficult to meet the water supply requirements of rural towns where tens of thousands of people reside. Therefore, a simpler water treatment system which can be operated inexpensively from a maintenance point of view is necessary in place of the rapid sand filtration system. Kambia Waterworks Madina Waterworks Port Loko Waterworks Magburaka Waterworks Existing Waterworks destroyed during the Civil War (Rapid Sand Filtration System: Degremont Type) JICA-Net マルチメディア教材 -3-

5 2. Purpose of the Project Rokupr water supply facility will be rehabilitated and renovated as a slow sand filtration facility under the Project, and its adaptability as a water treatment technology in rural towns will be inspected. At the same time, a water supply management system will be established and a method of water charge collection, etc. will be developed. Simultaneously, knowledge and know-how to be obtained during the implementation of the Project will be compiled as a model and disseminated to other rural towns in Sierra Leone. 3. Activities of the Project (1) Rehabilitation of the Exiting Facilities In order to rehabilitate the existing Rokupr water supply facility (refer to the next page) and to convert the existing water treatment system, a rapid sand filtration system into a slow sand filtration system, following activities were conducted in the Project. Site recognizance Water quality analysis on the raw water of the water treatment plant(swamp) Survey on defects of the existing water supply facilities Plan, design and cost estimation on the rehabilitation work Opening of tenders and tender evaluations Construction supervision Technical support of Japan s Grassroots Grant Aid project Procurement of equipment for the water treatment plant and for the O/M JICA-Net

6 Location of the Existing Rokupr Water Supply Facility JICA-Net マルチメディア教材 -5-

7 Water Analysis at Swamp Generator in the Plant Water Treatment Unit Survey on Pipes in the Plant Transmission Pump Flow Regulator Leakage from the Elevated Tank Exposed Distribution Pipes Survey on the Existing Water Supply Facilities JICA-Net マルチメディア教材 -6-

8 (2) Basic Design of Slow Sand Filter Before the civil war, water was taken from the swamp and the raw water was treated by the water treatment units which consist of three sets of sedimentation tank, rapid sand filter and clear water tank, and the treated water was transmitted to the elevated tank and then water is distributed in the town as shown in the figure below. Under the Project, in addition to the above existing system, a slow sand filter will be constructed and connection pipes are to be installed between the existing system and the new facility in order to convert the existing system, rapid sand filtration system into slow sand filtration system. Flow Diagram before and after the Project A basic structure and design of the slow sad filter are shown in the figure below: Basic Structure of Slow Sand Filter JICA-Net

9 (3) Rehabilitation Work of the Facility The rehabilitation work of the existing water supply facilities and a construction of the slow sand filter were conducted in accordance with the construction agreement signed between JICA Project Team and a local contractor (OTCC) on September The construction supervision was carried out by JICA experts and counterpart personnel of Water Supply Division (WSD) of the Ministry of Energy and Power and the work completed in March Base Concrete Work Form Work of Outer Wall Installation of Underdrainage Filter Sand Filling Construction of Slow Sand Filter Slow Sand Filter Constructed under the Project JICA-Net マルチメディア教材 -8-

10 Replacement of Exposed Pipe Repair of Water Leakage Reconstruction of Public Tap Replacement of Generators Other Rehabilitation Works Signing of the Contract (Feb ) Construction of Office Building Extension of Pipeline New Public Tap in the Expanded Area Japan s Grassroots Grant Aid Project JICA-Net マルチメディア教材 -9-

11 (4) Establishment of Operation and Management Organizations In order to establish organizations which will operate and maintain the rehabilitated Rokupr water supply facility and will manage the water service in Rokupr, following activities were conducted in the Project. Survey on the existing organizations Socioeconomic survey (questionnaire survey) Enactment of bye-law for establishment of a public utility (RWSSB) Establishment of Consumer Units Preparation of operation and maintenance plan & manual for the facilities Preparation of management plan & manual Training and OJT to the technical and administrative staffs of RWSSB JICA Project Team proposed to set up a public utility (Rokupr Water Supply and Sanitation Board: RWSSB) for the water supply under the Kambia District Council s jurisdiction. The organizations proposed under the the Project are illustrated below. Ministry of Energy & Power Water Supply Division (WSD) Report Advice Established based on the Bye-law Report Kambia District Council Instruction, Audit Dispatch Technical Staff Rokupr Water Supply & Sanitation Board (RWSSB) Admin. Staff Technical Staff Tariff Water Tariff Water Public Tap Consumer Unit Public Tap Consumer Unit Private Connection Private User Proposed Organizations for Water Service in Rokupr JICA Project Team also proposed to set up Consumer Units and appoint Unit Leaders which will maintain the public taps. The Unit Leader will collect water charges form households registered at each public tap and deliver the water charge to RWSSB. RWSSB allows to the Consumer Unit a maximum of 10% of the total collected water charge as commission. RWSSB can save personnel cost for the collection of water charges to do so JICA-Net

12 Stakeholder Meeting Preparatory Meeting for RWSSB Workshop to Unit Leaders RWSSB Board Meeting Community Meeting Community Meeting Activities for Establishment of the Organizations Training to Technical Staffs Training to Administrative Staffs Training and OJT to the Staffs of RWSSB JICA-Net マルチメディア教材

13 (5) Development of Tariff System In order to develop a water tariff and water bill collection system for the water service of Rokupr water supply facility, following activities were conducted in the Project. Questionnaire survey on willingness to pay Preparation of a tariff system and water bill collection plan Preparation of a consumer ledger, account books, etc. In the Project, basic concepts for development of water tariff are as follows: Afford able Fair Sustai nable Water bill shall be calculated as per the volume consumed. Water bill shall differ on family size. Water bill shall consist of unit prices of a fixed cost and a production cost for the water service. Water bill shall be enough to sustain the water service. In case of water supply by public taps, water bill is used to be a flat rate and users are sometimes discontented with the water bill from the point of view of fairness. In order to secure fairness for water bill of public taps, following measures were taken in the Project: Complaints about Water Bill for Public Tap Source of Discontent Consumption of water is different at each public tap, but water bill is a flat rate. Family size is different among the consumers, but water bill is a flat rate. Distance between the houses and the public tap is different, but water bill is a flat rate. Measures taken in the Project Flow meter is installed at each public tap to measure the consumption of water. Consumer Ledger is prepared and water bill is calculated as per the family size registered. New taps were constructed and all the consumers can access to the nearest public tap within 100m of their houses. Installation of Flow Meter Workshop on Pay for Water Activities for Development of Tariff System Water tariff of the water service of Rokupr water supply facility has been developed and water bill can be calculated according to the formula below: JICA-Net

14 Monthly Charge = (α x Per capita consumption x Unit price of production cost + Unit price of fixed cost) x Family size where; α : Coefficient for per capita consumption varies from family size Per capita consumption: Average monthly consumption per capita Family Size: Number of family Unit price of production cost: Le. 349/m 3 Unit price of fixed cost: Le. 366/person Consumption (m 3 /capita/month) Water Tariff (Public Tap) (Unit: Leone) Family Size (Persons) 1 to3 4 to 6 7 to 9 10 to to 15 Over ! ,000 2,300 3,500 4,700 5,900 7, ! ,400 3,000 4,300 5,800 7,000 8, ! ,700 3,800 5,200 6,800 8,100 9, ! ,100 4,500 6,000 7,800 9,200 10,500 Over ,500 5,200 6,800 8,900 10,300 11,500 Coefficient ( _) Note: 1US$ = Leone 2, Conclusion of the Project (1) Rehabilitation of the Exiting Facilities As a result of the above-mentioned activity, the existing water supply facilities have resumed their functions and the new slow sand filter shows its function as planed, and clean and safe water is being supplied to the residents. Further, the Grassroots Grant Aid project enables the resident of Rokupr to fetch water within 100m of their houses and it materialized fair access and high quality water service. Maintenance of Slow Sand Filter Safe Water Supply Clean Treated Water JICA-Net

15 (2) Establishment of Organizations As a result of the above-mentioned activity, the public entity for operation and management of the Rokupr water supply facilities (RWSSB) has been established legally. The staffs of both technical and administrative departments of the RWSSB have been stationed and trained during the Project. The staffs have sufficient capacity to conduct the practice of business and make the passing mark in the respective field. The RWSSB commenced commercial operation of the water service in October The Kambia District Council has established RWSSB as per the Bye-law. 11 Board Executives of RWSSB have been approved by the Council. 6 technical staffs are assigned to RWSSB from WSD and trained. 4 administrative staffs are are assigned by the RWSSB and trained. 35 Consumer Units have been established and Unit Leaders are appointed. (3) Development of Tariff System As a result of the above-mentioned activity, a fair tariff system for public tap which is similar to the tariff system for metered private connection. In case of family size of eight members and water consumption of 30 liter/day/capita, its water bill will be Le. 5,200 (= US$1.8) per month and it can be judged to be affordable, while bill collection ratio for the month of October 2008 is as low as 54% as of the end of December Recommendations and Lessons Learned Slow sand filtration is a suitable water treatment system for small towns in Sierra Leone in terms of both technical and economical aspects. Swamp is a potential and suitable water source for slow sand filtration in Sierra Leone through the year. The operation and management organization shall be established legally to secure its sustainability and justification of doing the water business. From the view point of fairness among the water users, strict measures shall be taken against the users who will not pay water bill including prohibiting such users from using taps, however, RWSSB is requested to explain them the importance of payment and their duty prior to taking such measures JICA-Net