Appropriate Water Supply Solutions for Bangladesh

Transcription

1 Appropriate Water Supply Solutions for Bangladesh SWECO APPROACH Dr. Jens Thøgersen Department Head, International Water Sweco s Water Supply Projects in Bangladesh Design & Management Consultancy for Dhaka Water Supply Sector Development Project (DWSSDP) ( ) Chittagong Water Supply Network Rehabilitation and Optimisation Project ( ) Padma (Jashaldia) Water Treatment Plant (Phase-I) Project ( ) Technical Assistance to Saidabad (Phase-II) Suface Water Treatment Plant Project ( ) 2

2 Dhaka Water Supply Sector Development Project Water Supply Situation in Dhaka Prior to Project Intermittent supply Outdated delivery network Widespread use of spaghetti lines pipes for service connections Widespread use of suction pumps causing negative pressures in the pipes NRW >35% (60% physical losses in pilot area) Unhygienic water boiling of water before drinking Low quality material and workmanship Illegal connections 4

3 Issues to be Considered in Urban Water Supply Holistic approach considering minimum the following issues: Source protection and development Supply mechanisms Network and pressure management Sustainability Energy efficiency Climate resilience Financial/economic concerns Tariff issues Private sector involvement 5 New Approaches Introduced in Dhaka State-of-the-Art/ Innovations of DWSSDP 24/7 pressurized supply DMA design Design-build Performancebased Works Contracts Trenchless laying of pipes New pipe materials 6

4 Outcome of the Project Installation of 1,800 km of distribution pipelines Reduction of NRW of the total system to less than 7% minimum pressure of 1 bar in all parts of the system 24/7 Division of the system into hydraulically isolated District Metered Areas (DMAs) Rehabilitation/reinstallation of all service connections people served No households need suction pump to get water Hygienic water people drink DWASA water without prior boiling >100 % increase in revenues from covered DMA s 7 Feasibility Study for Sustainable and Cost Effective Water Supply System

5 Feasibility Study for Sustainable and Cost Effective Water Supply Background of Study Current dependency on Ground Water Funding available as part of Saidabad II support Ground water abstraction inefficient & unsustainable Safe yield determined to be approximately 1200mld (assuming 60% of water abstracted by DWASA), well below current abstraction of 2000mld Water table falling up to 5m per year, with an average fall of 2.8m per year 9 Present Situation Summary Results & Analysis Static water level is falling, frequently leading to lack of cooling water which leads to motor burn out. Electrical installations are often poor Construction standards low Efficiencies very variable and no feedback from network Little preventative maintenance Manual operation means pumps work in isolation, leading to pressure & supply inconsistencies Low efficiencies and low water levels lead to high electricity consumption Lack of evidence based decision making contributes to breakdowns, higher maintenance costs and overall lower levels of service. 10

6 Goals / Targets to be Achieved What are the goals? To reduce the falls in water table How are these best achieved? Reduce abstraction! To reduce pump failures To improve pump efficiencies Protect the pumps using technology Improve asset base and operate 11 Feasibility Study Outcome Recommendations: Physical Improvements Rehabilitate wells where necessary Install new efficient pumps with automatic controls and VFDs Install SCADA Managerial & Staff Changes Implement change management programme, capacity building (restructuring of water production) and training in new skills (SCADA, electrical and electronic engineering) 12

7 Jens Thøgersen Head of Department International Water