Project Implementation Agency: National Water Supply and Drainage Board

145 Pages·2012·3.95 MB·English

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
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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
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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
3.3.2 Economic Environment ........................................................................................54
3.3.3 Institutional Environment ......................................................................................55
3.3.3.1 Capacity of the O&M Institution ............................................................................55
3.3.3.2 Issues associated with Project being located outside of the service area .............55
3.3.4 Social and Institutional Threats ............................................................................55
4.0 DESCRIPTION OF ANTICIPATED ENVIRONMENTAL IMPACTS ................................ 57
4.1 Construction Phase .....................................................................................................57
4.1.1 Impacts of land clearing and development ...........................................................57
4.1.2 Noise, vibration and dust due to construction activities ........................................57
4.1.3 Transportation of heavy vehicles with filling / spoil materials ................................58
4.1.4 Air quality impacts from traffic during transportations of material and equipment .58
4.1.5 Impact on natural drainage pattern due to construction activities .........................58
4.2 Operational Impacts ....................................................................................................58
4.2.1 Impacts on water resources .................................................................................58
4.2.2 Impacts due to release of obnoxious gases .........................................................59
4.2.3 Impact due to Movement of Gully Trucks .............................................................59
4.3 Impacts on Ecological Resources (Construction and Operational) ..............................60
4.3.1 Destruction or alternation of habitats ....................................................................60
4.3.2 Affects on the prevailing ecosystem balance .......................................................60
4.3.3 Impacts on terrestrial and aquatic flora and fauna ................................................60
4.3.4 Impacts on receiving water-body..........................................................................60
4.4 Impacts on Socio-economic Environment (Construction and Operational) ..................61
4.4.1 Social economic benefits (Health etc) ..................................................................61
4.4.2 Impact due to land-use change ............................................................................61
4.4.3 Impact on land values ..........................................................................................61
4.4.4 Impact on quality of life ........................................................................................61
4.4.5 Employment opportunities....................................................................................62
4.4.6 Resettlement requirements (if any) ......................................................................62
4.4.7 Social impacts due to transportation of septage ...................................................62
4.5 Any other Impacts .......................................................................................................62
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5.0 PROPPOSED MITIGATORY MEASURES .................................................................... 63
5.1 Mitigatory Measures proposed for Constructional Impacts ..........................................63
5.1.1 Mtigation of Impacts due to land clearing and development .................................63
5.1.2 Establishing a green belt ......................................................................................63
5.1.3 Mitigatory Measures for Noise and Vibration Impacts ..........................................63
5.1.4 Mitigatory Measures for Impact on Air Quality ......................................................64
5.1.5 Mitigatory Measures for Impacts due to Burrow Pits ............................................65
5.1.6 Mitigatory Measures for Impacts due to Waste Disposal ......................................65
5.1.7 Mitigatory Measures for impact on natural drainage pattern due to construction
activities ...........................................................................................................................66
5.2 Mitigatory Measures for Operational Impacts ..............................................................66
5.2.1 Mitigatory Measures for impacts on water resources ...........................................66
5.2.2 Mitigatory Measures for impacts due to release of obnoxious gases ....................66
5.2.3 Mitigatory Measures for impact due to Movement of Gully Trucks .......................67
5.2.4 Sludge disposal ...................................................................................................67
6.0 ENVIRONMENTAL MONITORING PROGRAM ............................................................. 68
6.1 Introduction .................................................................................................................68
6.2 Compliance Monitoring ...............................................................................................68
6.3 Effects Monitoring .......................................................................................................68
6.4 Environmental Monitoring Committee (EMC) ..............................................................69
7.0 PUBLIC CONSULTATION AND INFORMATION DISCLOSURE .................................. 74
7.1 Methodology adopted .................................................................................................74
7.2 Consultation and disclosure events .............................................................................74
7.3 Awareness ..................................................................................................................75
8.0 FINDINGS AND RECOMMENDATIONS ........................................................................ 77
8.1 Suitability of the Site ...................................................................................................77
8.2 Regulatory Environment..............................................................................................77
8.3 Impact on Physical Environment .................................................................................77
8.4 Impact on Social Environment ....................................................................................77
8.5 Impact on Biological Environment ...............................................................................77
8.6 Operation of the Plant .................................................................................................77
8.7 Overall Findings and Recommendations .....................................................................78
9.0 CONCLUSIONS ............................................................................................................. 79

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APPENDICES

Appendix 1: References
Appendix 2: Survey Plan of the Land
Appendix 3: Approval / Consent Letters
Appendix 4: Septage Treatment Plant Design Details
Appendix 5: Photographs of Alternative Site
Appendix 6: Water Quality Analysis Reports
Appendix 7: Plant Species Observed in the Direct Impact Zone of the Project Site
Appendix 8: Animal Species Recorded within the Various Habitat Types Observed in the
Direct Impact Zone of the Project Site
Appendix 9: List of Meetings / Discussions Conducted During IEE Study and Attendance
Lists
Appendix 10: Meeting Minutes of Public Consultation Meeting
Appendix 11: List of Environmental Study Team Including their Work Allocation
Appendix 12: Terms of Reference

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ABBREVIATIONS
ADB - Asian Development Bank
APS - Arachchikattuwa Pradeshiya Saba
BOD - Biological Oxygen Demand
CBO - Community Based Organizations
CCD - Coast Conservation Department
CEA - Central Environmental Authority
COD - Chemical Oxygen Demand
CPS - Chilaw Pradeshiya Saba
CUC - Chilaw Urban Council
DO - Dissolved Oxygen
DSD - Divisional Secretariat Division
DZUWSSP - Dry Zone Water Supply and Sanitation Project
EIA - Environmental Impact Assessment
EMC - Environmental Monitoring Committee
EMP - Environmental Monitoring Plan
EPL - Environmental Protection License
GND - Grama Niladhari Division
H&S - Health and Safety
HFL - High Flood Level
IEE - Initial Environmental Examination
LA - Local Authority
MCM - Million Cubic Meters
NLDB - National Livestock Development Board
NO - Oxides of Nitrogen
x
NWPEA - North-Western Provincial Environmental Authority
NWS&DB - National Water Supply and Drainage Board
O&M - Operation and Maintenance
PPTA - Project Preparatory Technical Assistance
PS - Pradesiya Sabha
SLS - Sri Lanka Standards
SO - Oxides of Sulfur
x
SS - Suspended Solids
STP - Septage Treatment Plant
ToR - Terms of Reference
UDA - Urban Development Authority
USEPA - United States Environmental Protection Agency
WWTP - Waste Water Treatment Plant
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EXECUTIVE SUMMARY
Dry zone urban areas face acute water shortages during dry period of the year. Proposed
Dry Zone Water Supply and Sanitation Project (DZUWSSP) is designed to address this
issue for four towns in the dry zone. Project also includes a sanitation component. Under this
component development of proper septage disposal facilities and provision of toilets for
household without such facilities are planned. Chilaw is one of the urban centers included in
the DZUWSSP. This Initial Environmental Examination evaluates the environmental impacts
of proposed septage treatment facility for Chilaw and recommendations for environmental
impact mitigation. It also includes Environmental Management Plan explaining the
implementation and monitoring of environmental actions and impacts.
This project is not a prescribed project under the North-Western Provincial Environmental
Statute. Thus it does not require EIA/IEE clearance for implementation. However,
preparation of EMP is a requirement for the ADB, which is the funding agency. Nevertheless
the presence of minor irrigation tank in close proximity drew the attention of the North-
Western Provincial Environmental Authority (NWPEA) and Agrarian Services Department for
this project. Both agencies indicated that they will determine on the project based on the
findings of this IEE.
Project proponent had looked into project alternatives in detail. Alternatives were considered
under three categories: (a) Alternative Methods of Disposal, (b) Alternative Technologies
under the chosen method and (c) Alternative Sites. After careful consideration pond based
biological treatment of septage is selected as the technological choice where the treated
effluent can be disposed either on-site or off site based on the saturation level of the soil.
Choice of pond based system is appropriate considering low operational cost and low
technological complexity. Climatic conditions of SriLanka suit this treatment method well.
Low technological complexity is an important consideration as the plant will be operated and
maintained by the Chilaw Urban Council (CUC). Proponent has considered several
alternative sites before selecting the proposed site at Arachchikattuwa for this project.
There are few drawbacks in terms of site suitability for the proposed project. Key issues are
water logging and flooding of part of the land. However these drawbacks can be overcome
by proper planning and design. Given the scarcity of lands suitable for this type of project the
choice of site is acceptable. Adequate buffer against sensitive land-uses are available.
Environmental impacts of the proposed project during construction and operations are not
very significant. Construction impacts can be easily managed by adopting good
management practices. Operational issues can be addressed through design and
operational measures. Site sensitivity is a key issue due to the presence of a minor tank in
the adjacent land with its High Flood Level (HFL) extending partly to the proposed site.
However, the plant is located outside of 100m from the HFL. Other major concerns include
high water table, water logging and minor flooding. Construction of all weather access road,
land development to prevent water logging, provision of proper drainage facilities and treated
effluent disposal arrangement linked to water table level are included in the mitigation plan.
Treated effluent can be discharged safely during the dry periods. Additional storage pond to
retain the treated effluent during wet period is included in the design. Treatment process
allows digestion of anaerobic sludge for one year. This will make sludge stabilized and
conditioned for land disposal. The plant design has significantly reduced environmental
impacts and the environmental risks due to extreme events. Site ecology is already
disturbed and ecologically the site can be considered as not sensitive. There are no major
social or resettlement issues. However, project is socially sensitive due to its nature. Direct
access to the site is available from the main road. Thus gully trucks need not travel through
village interior or use village roads. The setting of the site is such that direct visibility of the
site to community can be fully avoided. This is a major advantage and IEE consultants at this
stage do not see major opposition from the community towards the project.
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IEE Consultants recommends implementation of this project subjected to the implementation
of proposed mitigation measures and approval by relevant authorities. IEE Consultants also
recommend project benefits to be made available to the community living in the project site
area through provision of household sanitation support targeting the needy families.
Environmental Management Plan (EMP) and monitoring plan is included in the IEE Report to
ensure the compliance with IEE recommendations and for effective monitoring.

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1.0 INTRODUCTION
1.1 Project Name
Construction of Septage Treatment Plant (STP) for Chilaw under the Dry Zone Urban Water
and Sanitation Project (DZUWSSP)
1.2 Details of the Project Developer
Name of the Developer: National Water Supply and Drainage Board (NWS&DB)
Contact Name: Mr. Mohan Lechuman (Project Manager – Chilaw)
Project Office
Address: ADB 5th Project Office
National Water Supply and Drainage Board
No 68, Ebert Lane, Kaldemulla
Moratuwa
Telephone: [phone]
077-2240570 (Mobile / Project Manager)
Fax: [phone]
E-mail: [email protected]

Site Office
Address: ADB 5th Project Manager’s Office
National Water Supply and Drainage Board
1st Floor, No. 1, Jetty Street
Chilaw
Telephone: [phone]
Fax: [phone]
E-mail: [email protected]

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