Bangladeshi arsenic- and salt-mitigation sourcebook and decision-support tool Final report In partial fulfilment of the ASTRA-Bangladesh project (BRAC WASH II program) [Page intentionally left blank] 2 COLOPHON This document was prepared in the project ‘Aiding Sustainable Water Technology Realization in Arsenic contaminated Areas of Bangladesh’ or for short ‘ASTRA-Bangladesh’ in the framework of the BRAC WASH II program (http://www.irc.nl/brac). This program is managed by BRAC and IRC International Water and Sanitation Centre and funded by the Embassy of the Kingdom of the Netherlands (Bangladesh). Written by Dr.ir. Gábor SZÁNTÓ PRACTICA Foundation Dr.ir. Doris van HALEM Delft University of Technology Samuele OLIVERO, MSc Delft University of Technology Prof.dr.ir. Louis C. RIETVELD Delft University of Technology Alida PELGRIM-ADAMS, MSc PRACTICA Foundation Dipok Chandra ROY, MSc PRACTICAL ACTION Bangladesh Jacqueline BARENDSE, MBA WASTE Foundation Valentin POST, MSc WASTE Foundation Software (at ASTRAdst.info) is by Menno BISCHOPS, BSc [VRConcepting] Color drawings by Susanna Horn Jardemark, MSc 3 [Page intentionally left blank] 4 ACKNOWLEDGMENTS This book lists eight names as authors, but that’s only accurate if it is to cover those responsible for its content. There are several more who contributed with information regarding the approach, structuring and content of the described mitigation strategy and also the related technology information sheets. For this reason, the authors gratefully acknowledge the information and cooperation provided by Ms. Ingeborg Krukkert and Mr. Jan Willem Dogger (IRC) and for the expert guidance of Dr. Mofazzal Hoque (BRAC). The authors are also thankful for the final comments of Mr. Arif Waliullah Bhuiyan (BRAC). The authors are indebted to Dr. Kurian Baby (IRC) whose views and guidance were essential in the development of the ASTRA tool. The authors also want to express their gratitude to numerous Bangladeshi and international water supply experts. A wealth of information from arsenic mitigation practice could be gathered thanks to their selfless sharing of knowledge. Some of their experience is now available in this document for the advancement of water provision in Bangladesh. This publication and the related research was realized with the financial support of the BRAC WASH II programme. 5 [Page intentionally left blank] 6 SUMMARY This publication contains the detailed description of the ASTRA arsenic- and salt-mitigation tool developed in the framework of the BRAC WASH II programme. In essence, this work is a supporting compendium and tool for decision-makers, practictioners and education institutes. It’s main objective is to aim understanding and identification of potentially appropriate technological solutions to tackle the widespread arsenic and salinitiy problems in the water sources of Bangladesh. Confirm the currently available solutions, the work leans towards the removing or mitigating of arsenic and – where treatments are included – solutions that mainly concern disinfection and (in)filtration. The contained information draws on both Bangladeshi and international research and practical experience. The general mitigation strategy is explained as the identification of potentially appropriate water supply methods for implementation in Bangladesh. The identification process is based on a multidisciplinary assessment and matching of method functionality with the intended local context. This book contains both the critical reviews and practical information of all potentially applicable technical mitigation methods to aid decision-makers and engineers. In the first chapter of the publication, the growing water stress and its key drivers in Bangladesh are listed and detailed. This sourcebook section enables the proper understanding of mitigation methods through a range of critical reviews that can either treat or circumvent arsenic- or salt-contaminated sources. Three mitigation routes are outlined that include water supply or treatment methods. These mitigation options are to (i) target arsenic- or salt-free groundwater, (ii) treat arsenic- or salt- contaminated groundwater or (iii) disinfection of alternative, non-groundwater sources. Utilizing one or more of the identified mechanisms, 26 specific technological methods are identified as eligible for the Bangladeshi water sector context. Their in-depth descriptions are given in chapter 6 of this book. The descriptions of technical, institutional, ecological and socio-economic features are completed by eligibility matrices. The matrices demonstrate quality of functioning according to local- or project-specific criteria and allow users to assess performance of the method in the context of application. The description of the content of the decision-suport tool are coupled to the manual on how to use it and the related online version. Finally, a discussion is offered that tackles indirect considerations that Bangladeshi water experts could apply to further improve the sustainability of the local water sector. The chosen structure of this publication allows two distinctively different utilizations. Decision- makers and engineers may view potential approaches first before formulating specific strategies to mitigate the arsenic-related problems. As the compendium section is also possible to use without the more theoretical initial parts, especially field experts are hoped to benefit from the technology information sheets and matrices during multistakeholder processes of water projects. 7 [Page intentionally left blank] 8 Table of Contents 1 Introduction ................................................................................................................................... 15 1.1 Rationale of arsenic- and salt-mitigation in Bangladesh ....................................................... 15 1.1.1 Challenges in Bangladeshi water supply ....................................................................... 15 1.1.2 Overview of the arsenic- and salt-mitigation challenge ................................................ 15 1.2 Development of the ASTRA arsenic- and salt-mitigation strategy ........................................ 17 1.2.1 The BRAC WASH II programme ..................................................................................... 17 1.2.2 The ASTRA project ......................................................................................................... 17 1.2.3 Methodology ................................................................................................................. 18 1.3 Structure of the book ............................................................................................................ 19 2 Description of the general mitigation strategy ............................................................................. 21 2.1 The ASTRA approach ............................................................................................................. 21 2.1.1 Brief historical overview of sourcebooks and decision-support tools .......................... 21 2.1.2 Description of the mitigation approach ........................................................................ 23 2.2 Context analysis ..................................................................................................................... 25 2.2.1 Introduction ................................................................................................................... 25 2.2.2 Natural context .............................................................................................................. 25 2.2.3 Human context .............................................................................................................. 26 2.2.4 Technical context ........................................................................................................... 26 2.3 Technical mitigation approaches........................................................................................... 27 2.3.1 Assessment of potential approach ................................................................................ 27 2.3.2 Targeting arsenic- and salt-free groundwater............................................................... 28 2.3.3 Treatment of arsenic- and salt-containing groundwater .............................................. 30 2.3.4 Appropriate non-groundwater alternatives .................................................................. 32 2.4 Matching context and eligibility – the ASTRA tool ................................................................ 33 2.4.1 Classification of the knowledge base ............................................................................ 33 2.4.2 The eligibility screening ................................................................................................. 36 2.4.3 Determining the pool of potential methods ................................................................. 37 2.4.4 Method selection and post-implementation assessment ............................................. 38 2.5 Intended users and use of the ASTRA approach ................................................................... 38 2.5.1 Decision-makers and practicioners ............................................................................... 38 2.5.2 Multistakeholder processes .......................................................................................... 39 2.5.3 Education and research institutes ................................................................................