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Electrochemical Arsenic Remediation in Rural Bangladesh
EPA Grant Number: SU834017Title: Electrochemical Arsenic Remediation in Rural Bangladesh
Investigators: Gadgil, Ashok , Amrose, Susan , Cheng, Debbie , Huang, Jessica , Kostecki, Robert , Kowolik, Kristin , Muller, Marc , Sedlak, David L. , Srinivasan, Venkat
Institution: University of California - Berkeley
EPA Project Officer: Nolt-Helms, Cynthia
Project Period: August 15, 2008 through August 14, 2010
Project Amount: $75,000
RFA: P3 Awards: A National Student Design Competition for Sustainability Focusing on People, Prosperity and the Planet - Phase 2 (2008)
Research Category: Pollution Prevention/Sustainable Development , P3 Challenge Area - Water
Description:
Objective:Arsenic in drinking water is a major public health problem threatening the lives of over 140 million people worldwide. In Bangladesh alone, between 35-77 million people drink arsenic-laden water from shallow wells, leading to what has aptly been called the largest mass poisoning of a population in history. Over one million deaths are expected due to arsenic-related cancer in Bangladesh. Millions more will suffer from arsenic-related medical conditions unless something is done.
The primarily rural population of Bangladesh is too poor to afford arsenic remediation techniques that are cost effective only on large scales. Current technical approaches to low-cost arsenic removal involve the addition of chemical adsorbents, which frequently exhibit one or more of the following environmentally degrading qualities: toxicity, use of strong alkalies or corrosive acids to regenerate, production of large quantities of arsenic-laden toxic waste, a short shelf life, and/or the need for an extensive supply chain with corresponding greenhouse gas emissions. In addition, these technologies are often deployed as point-of-use devices, to be operated and maintained by the user. Point-of-use systems have been plagued by high abandonment rates after a short time due to difficult maintenance or operation, lack of time to devote, and low cultural acceptability. A new model is needed to ensure sustainability of water treatment for future generations.
Electrochemical Arsenic Remediation (ECAR) overcomes many of the obstacles of chemical adsorbents and can be used affordably and on a small-scale, allowing for rapid dissemination into rural Bangladesh. In EC, electricity is used to continuously dissolve an iron anode, forming corrosion products (collectively called ferric (hydr)oxides or rust). Thus the arsenic adsorbent is manufactured at the time of use - eliminating the need for a costly supply chain. In addition, this process greatly enhances the capacity of rust to adsorb arsenic, due to (i) an increase in the rate of rust production (by factors of 10 to 100 over natural rusting rate of metallic iron), and (ii) the rapid oxidation of As(III) in the water to the more favorable As(V) which binds much more readily to rust. Thus the employment of a small amount of electricity leads to a large advantage in efficiency, lowering the cost and producing far less waste than chemical adsorbents. In addition, the electrodes are self-cleaning if current is alternated, reducing maintenance and eliminating the need for corrosive acids or toxic chemicals for regeneration.
The objective of this project is to combine the attractive properties of ECAR with an economically sustainable model for clean water delivery to help mitigate the arsenic crisis in Bangladesh.
Approach:The main disadvantage of EC in rural areas is the need for electricity, albeit a small amount. However, if the operating costs are low enough, modest profits on the treated water can attract business investment making the model rapidly scalable, while fully recovering the cost of an electricity source, maintenance, and operation and ensuring that local villagers continue to have stake in successfully operating the technology. The retail cost remains affordable to the poor (1-2¢ US for 10 liters per day). In light of the barriers that plague point-of-use systems, a community-scale kiosk model is a promising way to sustain clean water access long term.
Phase I tested and optimized the arsenic removal efficacy of ECAR in Bangladesh. In Phase II, we will bring the technology from a lab prototype into a working pilot project providing clean water to a village in Bangladesh with full cost recovery.
We will meet the challenge of Phase II with several key objectives:
- Prove technical viability of the ECAR prototype under continuous use in Bangladesh. We will conduct two technical field trials of increasing rigor during which we will clean and monitor groundwater water using our prototype device. For the extended trial, we will partner with a village to provide temporary clean water free of cost (without compromising villagers’ access to current water sources) and gather information on the social acceptability of the water, including taste and color. Waste removal strategies will be tried and evaluated.
- Develop a pilot scale business plan with full cost recovery suitable for rural Bangladesh. This will be done in parallel with (1) and will include waste removal strategies tested during (1).
- Design, develop and implement a pilot project incorporating full cost recovery, including pre-pilot economic surveys, along with public health education and outreach (post-project surveys will occur after the two-year Phase II period).
Success in Phase II will provide a financially and environmentally sustainable model for providing clean water to Bangladeshi villages ready to transfer to the commercial sector for long-term operation, replication and scale-up. We will have acquired critical new knowledge on the willingness to pay for clean water in Bangladesh, as well as the viability of full cost recovery for a system incorporating an off-grid power supply. We will have knowledge and experience of using ECAR in the field that will aid design for mass production, provide key business model inputs such as maintenance and monitoring requirements, as well as a working demonstration in the field to attract investors. Most importantly, we will have an opportunity to discuss the technology and implementation with local stakeholders, and work together to see if ECAR is a viable arsenic remediation solution for Bangladesh.