Grant 13480946 optimizing dewatering of remote AMD treatment sitesdewatering sludges precipitated by chemical treatment with fine particle size characteristics is very challenging, often requiring…

This $199,994 cooperative agreement from the Department of the Interior Office of Surface Mining Reclamation and Enforcement will fund research to optimize dewatering of acid mine drainage treatment sludges through December 2025. The work falls under the Science and Technology Projects Related to Coal Mining and Reclamation program (CFDA 15.255), which aims to develop improved science-based technologies to address environmental restoration topics associated with coal mining.

Specifically, the awardee - West Virginia University Research Corporation - will study the chemical composition and dewatering properties of sludges from different acid mine drainage treatment sites. They will evaluate flocculation and precipitation procedures suitable for remote application and quantify dewaterability to customize chemical dosages by site. A bench-scale acid mine drainage treatment station will be reproduced in the lab to develop and test a methodology for improving sludge dewaterability and settling while evaluating cost-effective filtration media performance. The results could enhance efficiency and cost reduction in mining waste and byproduct handling across coal-producing states and tribes.

Grant 13480946 optimizing dewatering of remote AMD treatment sitesdewatering sludges precipitated by chemical treatment with fine particle size characteristics is very challenging, often requiring flocculants to be effectively filtered. Fine grain sludges often retain excess water in their structures due to electrical charges and their dewatering is also important for reducing transportation and disposal costs by volume reduction. Therefore, the need for improving the sludge dewatering characteristics while maintaining effective filtration is a goal to be addressed. Other industries such as wastewater and oil have been researching dewatering improving methods in their processes and have been successful. We propose to assess dewatering in acid mine drainage treatment sludges and we will address this goal by completing the following objectives objective 1 study different AMD treatment sludges chemical composition and solids dewatering propertiessampling and analysis of the sludge characteristics and chemistry is the first step to provide insights for effective treatment and to further evaluate the need for filtration and flocculation. In addition, a chemical composition analysis will provide insight for possible recycling of the generated sludge, such as feedstock for rare earth elements and critical minerals extraction, use as topsoil, and as construction materials. We propose to evaluate different precipitation flocculation procedures feasible for remote AMD treatment site applications. The current practice for flocculant selection is to perform a jar test and visually classify the chemical dosage. IT is common to use the one works for all approach and apply the same chemical dosage in treatment sites that would benefit from a different treatment. Different coal seams and weather conditions will demand different procedures to precipitate and efficiently dewater sludge. We will investigate dewatering capabilities by implementing the specific resistance to filtration (SRF) test to quantify the dewaterability of AMD sludges and customize the chemical dosage required for a specific site.objective 2 perform a field application by reproducing an AMD treatment station in the laboratory and indicating a filtration media for different grades of filtration efficiency VS. Costamd sludge commonly exhibits up to 2500 gravimetric moisture content. The ability to dewater AMD sludge will reduce the hauling volume and simplifies the potential methods for reuse. We will develop a methodology to improve the dewaterability of fine grain AMD sludge while evaluating cost effective filtration media performance and floc settling velocity. This methodology will result in an optimized settling, filtration, and dewatering cell. We propose to investigate the concept, develop predictive numerical solutions, and then advance to a bench scale proof of concept testing. These benefits could apply to any coal mining state, tribe, or OSM region that produces i) AMD in a remote site with passive treatments and need dewatering II) mine waste and would like to consider alternative means for waste handling and disposal. Finally, from the results of the proposed work, there is the potential for improving the efficiency and cost reduction in which the mining industry manages the waste and byproducts handling and reclamation activities.