|Cycle 2 (2012 Deadline)
Field assessment of arsenic-bearing waste treatment options
PI: Ahammadul Kabir (Asia Arsenic Network)
U.S. Partner: Lutgarde Raskin (University of Michigan)
Project Dates: August 2013 to February 2016
Water quality and supply issues in South Asia, dominated by concerns of arsenic contaminated groundwater and microbially contaminated surface water, are expected to worsen with the effects of climate change. Arsenic removal systems are essential for providing drinking water but generate arsenic-bearing wastes that can re-release arsenic to the environment. This project focuses on arsenic-bearing waste management, an issue preventing greater implementation of arsenic removal systems. By collaborating with researchers at the University of Michigan (UM) and consultants at Carollo Engineers, Dr. Kabir and his group will apply techniques developed through their lab studies to evaluate field-scale arsenic-bearing waste management options. Specifically, they will (1) analyze arsenic wastes from two types of arsenic removal systems, (2) evaluate alternative waste disposal options, and (3) quantify the arsenic-transforming potential of microbial communities in disposal environments.
A Sidko filtering machine in an arsenic iron removal plant (Photo courtesy Dr. Kabir).
| A backwash sludge water sample is collected from the arsenic removal plant (Photo courtesy Dr. Kabir).|
Collection of solid sludge samples nearby the arsenic removal plant (Photo courtesy Dr. Kabir).
The mitigation of arsenic contamination in drinking water in Bangladesh has the potential to improve the lives of millions of people in Bangladesh. Arsenic contamination of drinking water threatens human health and productivity by increasing morbidity and mortality (Argos et al. 2010). To properly address this barrier to development, guidelines for disposal of arsenic-bearing waste from arsenic removal systems must be established. This project will provide region-specific recommendations for arsenic-bearing waste management, enabling improved implementation of arsenic removal systems and enhancing the capacity of the Asia Arsenic Network (AAN) to provide clean drinking water. The results from this study will also inform decisions about how best to manage arsenic solids produced during water treatment to avoid recontamination of nearby soils and surface water with arsenic. AAN’s extensive outreach experience will be used to communicate findings with local arsenic removal plant operators and community members. AAN also works closely with local government officials and will communicate results and recommendations to policymakers. Planned training visits to the University of Michigan will also facilitate AAN’s capacity to conduct research and monitor water quality in Bangladesh, while upgrades to AAN’s lab equipment will enhance the organization’s capacity to test for multiple pollutants in drinking water, including not only arsenic but also microbial contaminants.
Summary of Recent Activities
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The third quarter of 2015 saw the project team busy with setting up and monitoring an outdoor experiment to test the performance of various types of arsenic-bearing concrete and brick under natural rainfall and temperature conditions. These ambient conditions were regularly recorded, and water washing over the samples was collected every 7 days and analyzed for arsenic content, pH, and oxidization reduction potential. The experiment began in July 2015 and will continue through November. In parallel, the team is also conducting strength tests on different varieties of concrete and brick containing arsenic-bearing sludge to determine whether their mechanical strength is compromised due to the incorporation of sludge. In addition to the tests on the concrete and brick isolation materials, the team also continued to collect fresh backwash sludge from 8 sites employing different arsenic removal technologies (5 arsenic iron removal plants and 3 SIDKO plants). Lined pit sludge was also collected at regular intervals from 6 arsenic removal sites (3 arsenic iron removal plants and 3 SIDKO plants) and tested for arsenic and other elements and compounds. In addition, soil/pit tank samples were collected and shipped to the team's U.S. partners at the University of Michigan for DNA extraction, gene sequencing, and characterization of the bacterial and archaeal communities found.
Two abstracts on research findings from this project have been presented this fall. The first, on “Safe handling and disposal of arsenic-bearing drinking water treatment wastes in Bangladesh,” was given at the University of Oklahoma International WaTER Conference 2015
in September and the second, on “Characterization of sludge generated arsenic removal technologies and possibility of polluting surrounding environment” at the 20th Arsenic Forum in Asia, held in Miyazaki, Japan, in November. As the project moves towards its expected completion date at the end of February 2016, the team will focus in the coming months on drafting a set of suitable best practices for arsenic bearing sludge disposal and recommendations on disposal practices. These will be disseminated to district-level water workers, professionals from various government departments and nongovernmental organizations, and other arsenic removal technology users.
Md. Shamim Uddin and Abu Shamim Khan during their 2014 training visit to the University of Michigan (Photo courtesy Dr. Kabir).
The month-long training session allowed the chemists to exchange ideas with their U.S. counterparts such as Tara Clancy, left (Photo courtesy Dr. Kabir).