Date of Award
Doctor of Philosophy (PhD)
Civil, Environmental & Architectural Engineering
R Scott. Summers
Detlef RU. Knappe
Karl G. Linden
Fenando L. Rosario-Ortiz
Contamination of drinking water sources by synthetic organic chemicals – such as pesticides, pharmaceutical residues, industrial effluents, and waste breakdown products – is a large and growing worldwide problem. Exposure can lead to cancer, birth defects, reproductive disorders, endocrine disruption, neurological dysfunction, organ damage, and other acute and chronic health problems. Pollution by anthropogenic chemicals is often more severe in developing countries compared to affluent regions as many substances that have been banned or restricted in Europe and North America are used or disposed of throughout the developing world in an unregulated manner. However, affordable and locally managed water treatment technologies deployable at the household and community scale in resource constrained and developing communities are lacking.
This thesis investigates the application of biomass char (“biochar” or charcoal) adsorbent produced using local resources for control of synthetic organic contaminants (SOCs) in decentralized water treatment. Laboratory batch isotherm tests and rapid small scale column tests were used to assess biochar adsorbents generated from as variety of feedstocks using artisanal charcoal kilns, biomass cookstoves, and biochar drum ovens used on small farms. Target SOCs included herbicides 2,4- dichlorophenoxyacetic acid and simazine, the human and livestock antibiotic sulfamethoxazole, the rodenticide and anticoagulant warfarin, and trihalomethane disinfection by-products. SOCs were introduced to biochars at environmentally relevant concentrations (μg/L to sub-μg/L) in representative surface water. Biochar efficacy for adsorption of SOCs was demonstrated to depend on production conditions – feedstock, temperature and duration of pyrolysis, and atmospheric conditions (draft and presence of oxygen) – the concentration of background dissolved organic matter, and the mode of contact (batch or column).
Laboratory research informed the design and implementation of multi-stage treatment systems incorporating biochar adsorbent for simultaneous control of both biological and chemical water pollutants. Over the research period of this thesis around one hundred community scale decentralized treatment systems were constructed by and with local colleagues from rural villages in SE Asia. This was accomplished using commonplace inexpensive tools and materials – in many cases even without electricity – underscoring the potential as an affordable and sustainable water treatment technology. Field observations of treatment systems further refined laboratory research methods, and led to the development of a novel “micro-column” test for quantifying SOC uptake from different representative waters by biochar and other carbonaceous adsorbents.
This thesis is intended to assist efforts by the water-sanitation-hygiene (WASH) development sector to provide water free from biological and chemical hazards in resource-constrained communities worldwide.
Kearns, Joshua Perry, "Biochar Adsorbent for Control of Synthetic Organic Contaminants in Affordable Decentralized Water Treatment" (2016). Civil Engineering Graduate Theses & Dissertations. 68.
Available for download on Sunday, September 27, 2020