Initial Environmental Examination Report Project Number: 37381-013 September 2012 Sri Lanka: DRY ZONE URBAN WATER AND SANITATION PROJECT - for Chilaw Septage Treatment Plant Prepared by Project Management Unit for Dry Zone Urban Water and Sanitation Project, Colombo, Sri Lanka. For Water Supply and Drainage Board Ministry of Water Supply and Drainage, Sri Lanka. This report has been submitted to ADB by the Ministry of Water Supply and Drainage and is made publicly available in accordance with ADB’s public communications policy (2005). It does not necessarily reflect the views of ADB. Project Implementation Agency: National Water Supply and Drainage Board Funding Agency: Asian Development Bank Project Number: 4853-SRI Sri Lanka: Dry Zone Urban Water and Sanitation Project (DZUWSP) INITIAL ENVIRONMENTAL EXAMINATION: SEPTAGE TREATMENT PLANT FOR CHILAW (DRAFT) MAIN TEXT DECEMBER, 2011 i TABLE OF CONTENTS TABLE OF CONTENTS ............................................................................................................. ii ABBREVIATIONS ..................................................................................................................... vi EXECUTIVE SUMMARY ............................................................................................................ 1 1.0 INTRODUCTION .............................................................................................................. 3 1.1 Project Name ............................................................................................................... 3 1.2 Details of the Project Developer ................................................................................... 3 1.3 Key Information on the Project ..................................................................................... 4 1.4 Ownership of the Project Site ....................................................................................... 4 1.5 Project and Study Background ..................................................................................... 4 1.6 Purpose of the Initial Environmental Examination (IEE) ............................................... 5 1.7 Extent and the Scope of the IEE Study ........................................................................ 5 1.7.1 Government policy / status regarding the project .................................................. 5 1.7.2 Applicable laws, regulations, standards and requirements .................................... 6 1.7.3 Approvals needed for the proposed development ................................................. 6 1.7.4 Conditions laid down by the Government Agencies .............................................. 6 1.7.5 Checklist on Sensitive Areas ................................................................................. 7 2.0 DESCRIPTION OF THE PROJECT AND ALTERNATIVES CONSIDERED .................... 8 2.1 Aim and Scope of the Proposed Project ....................................................................... 8 2.1.1 Category of Project: .............................................................................................. 8 2.1.2 Type of project ...................................................................................................... 8 2.1.3 Project main objectives ......................................................................................... 8 2.1.4 Main beneficiaries ................................................................................................. 8 2.1.5 Socio-economic effects ......................................................................................... 8 2.1.6 Description of the project ...................................................................................... 8 2.1.7 Project components .............................................................................................. 9 2.1.8 Project Layout ....................................................................................................... 9 2.1.9 Operation and Maintenance .................................................................................. 9 2.1.10 Size or magnitude of operation ............................................................................. 9 2.2 Justification of the Project ...........................................................................................11 2.3 Location ......................................................................................................................12 2.3.1 Location of Treatment Plant Site ..........................................................................12 2.3.2 Service Area ........................................................................................................14 2.4 Process Description and Design Details .....................................................................16 2.4.1 Brief description of the treatment process ............................................................16 2.5 Pre-construction and Construction Activities ...............................................................17 2.5.1 Pre-construction work ..........................................................................................17 2.5.2 Construction work ................................................................................................17 2.5.3 Construction cost .................................................................................................17 2.5.4 Construction labor requirement (both skilled and non skilled) ..............................18 2.5.5 Construction materials .........................................................................................18 2.6 Schedule of Implementation ........................................................................................18 2.7 Operation and Maintenance ........................................................................................18 2.7.1 Operational and Maintenance cost .......................................................................18 2.7.2 Institutional arrangement for operation .................................................................19 2.7.3 Capacity to meet the O&M expenditure................................................................19 2.7.4 Septage collection and delivery ...........................................................................19 2.7.5 Operation and Maintenance of treatment plant ....................................................19 2.7.6 Skills requirements...............................................................................................20 2.8 Evaluation of Alternatives............................................................................................20 2.8.1 Alternative Technologies ......................................................................................20 ii 2.8.1.1 Technology of Choice ..........................................................................................21 2.8.2 Alternative Designs ..............................................................................................21 2.8.2.1 Design of Choice .................................................................................................23 2.8.3 Alternative Sites ...................................................................................................23 2.8.3.1 Site of Choice ......................................................................................................28 2.8.4 No Action Alternative ...........................................................................................28 3.0 DESCRIPTION OF ENVIRONMENT .............................................................................. 30 3.1 Physical Environment .................................................................................................30 3.1.1 Study Area ...........................................................................................................30 3.1.2 Topography .........................................................................................................32 3.1.3 Soils and Geology ................................................................................................32 3.1.4 Climate ................................................................................................................33 3.1.5 Drainage ..............................................................................................................35 3.1.6 Surface Water ......................................................................................................38 3.1.7 Groundwater ........................................................................................................41 3.1.8 Land-use ..............................................................................................................42 3.1.9 Air and Noise Environment ..................................................................................44 3.1.10 Natural Disasters and Risks .................................................................................44 3.2 Ecological Environment ..............................................................................................45 3.2.1 Description of the existing ecosystem dynamics ..................................................45 3.2.2 Key Ecological Characteristics .............................................................................45 3.3 Socio-economic Environment .....................................................................................48 3.3.1 Social Environment ..............................................................................................48