University of Colorado Boulder
Matthew Bentley is a PhD candidate in Environmental Engineering for Developing Communities at the University of Colorado Boulder, where he studies low-cost water treatment in resource-limited scenarios. He received his Bachelor of Science in Engineering at Union University and his Master of Science in Environmental Engineering at the University of Colorado Boulder. Matt’s research focuses on removing toxic organic contaminants from drinking water, wastewater, stormwater, and landfill leachate.
Currently, Matt’s work involves the use of biochar, a sustainably-produced, low-cost, charcoal material for the sorption of aqueous organic contaminants. His recent work has broad application for water quality globally, and he has worked and collaborated with partners in the United States, China, Thailand, Myanmar, and India to improve drinking water quality and environmental health through biochar water treatment systems. Matt has developed low-cost techniques to improve biochar performance that can be adopted in remote communities to improve drinking water quality in areas impacted by toxic chemicals. In addition to his work in water quality, Matt has experience working on interventions in air quality, environmental health, livelihoods security, and urban refugee resettlement.
Matt is also a Research Partner at Yunnan Coffee Traders, where he is engaged in research initiatives and interventions promoting Water, Sanitation, and Hygiene (WASH) in remote communities and environmental sustainability throughout the coffee supply chain.
Improving removal of organic contaminants in alternative water treatment by biochars pretreated with ash, acid, and base
As water scarcity and vulnerability of drinking water supplies increase, water reuse becomes an important alternative for meeting the drinking water demand. Water reuse scenarios require the efficient use and treatment of alternative sources such as wastewater (WW) and stormwater (SW) for provision of clean drinking water, which often contain toxic organic contaminants. In addition, water reuse can magnify concentrations of emerging organic contaminants that are recalcitrant in commonly used treatment trains. Appropriate treatment methods are required that can remove these contaminants cheaply and effectively across these treatment scenarios of growing importance. Biochar is a promising alternative to activated carbon (AC) for organic contaminant removal, as it is low-cost, produced locally, and highly sustainable. This study investigates the performance of biochars produced from pine and WW biosolids for the removal of 2,4-Dichlorophenoxyacetic acid and Sulfamethoxazole, an herbicide and antibiotic respectively, in alternative water treatment scenarios. The performance of pine and biosolids biochars are compared with powdered activated carbon (PAC) in waters from three sources: Big Elk Meadows (BEM) Lake, representing a typical unimpacted drinking water source; secondary WW effluent; and urban SW from the University of Colorado Boulder campus. The primary limitation of biochar as a sorbent material has been the lower sorption capacity of most biochars compared to commercially-available AC. Some studies have evaluated the efficacy of “improved” biochars that have undergone expensive and complicated pre- and post-treatment methods to improve sorbent performance, but many of these methods lack practicality and negate biochar’s cost-savings over AC, which is one of its primary advantage. This study evaluates three low-cost, single-step pretreatment processes with ash, base, and acid. Ash pretreatment utilizes ash from the raw material to produce a dissolved leachate solution that is used to soak the raw material prior to pyrolysis. Base and acid pretreatment involve soaking the raw material in a solution with a high and low pH, respectively. These pretreatments add only a single step to the biochar production process, are low-cost, and use materials that are readily available in communities globally. Extensive results from 3-hour and 7-day batch sorption tests indicate that pretreatments of biochar feedstocks with ash, base, and acid can increase the sorption of organic contaminants from BEM, WW, and SW, making biochars up to 10x more competitive with AC in alternative water treatment and water reuse than untreated biochars. The impacts of these pretreatments on pine and biosolids biochars are investigated in this study, as well as the effect across background matrices. Simple, low-cost biochar improvement methods such as those implemented in this study have potential to make biochar competitive with AC in alternative treatment scenarios such as water reuse, source water protection, and developing communities, where organic contaminants are a threat to environmental and public health.