Polluted water is a pressing burden for civilization. Management and treatment of polluted water is a costly but necessary process for the health of the environment and the humans that live in it. Demand for novel, inexpensive, and effective treatment options is constant, and further insight on their use and impacts are as important as ever for our changing world. Two such sources of polluted water are analyzed in this document: acid mine drainage and urban stormwater runoff.
Acid mine drainage (AMD), a negative consequence of the mining industry resulting from interaction between water, oxygen, and exposed bedrock, is prevalent worldwide and requires expensive and perpetual treatment. The Wilds, an animal reserve in southeastern Ohio situated on a retired strip mine site, has partnered with OSU to address AMD discharging into streams and ponds on its property. Pervious concrete has shown potential in neutralizing AMD, and this study was developed to determine the effectiveness of pervious concrete at removing heavy metals and neutralizing acid from an AMD source. Using various mix designs of pervious concrete, the individual removal behavior of aluminum, manganese, iron, and copper from natural and synthetic AMD sources was tracked. Pervious concrete cylinders were also used to model the length of a permeable reactive barrier to treat field-scale AMD. Furthermore, acid neutralization ability and durability of six concrete mixes were tested when exposed to a year of acidic conditions. Experimentation revealed the concrete removes >95% of aluminum, iron and copper, and ~30% of manganese in natural AMD over 24 hours. Column testing indicated permeable reactive barriers of 4-8 meters in length are recommended to treat Al, Fe, and Cu. Pervious concrete compressive strength withstood a year of acid attack without significant decline, and results show a promising argument for the use of porous concrete in acid mine drainage treatment at field scale.
Lakes and rivers represent tremendous assets in the state of Ohio, as they are used for recreation, tourism, drinking water sources, commerce, and to support fisheries. Upland areas, including agricultural and urban lands, result in substantial pollution discharge to surface waters during runoff events, including nutrients from fertilizer, manure, and other sources. One negative consequence of nutrients in runoff is harmful algal blooms (HABs), which may contain various toxins and utilize dissolved oxygen in the water, causing fish kills to occur. The strength and scope of HABs is related to the nitrogen to phosphorus (N:P) ratio in runoff. Little is known about how urban land use and the presence or absence of stormwater control measures (SCMs) impacts the N:P ratio in stormwater. Two data sets were utilized to unpack these questions: (1) a land use and stormwater quality data set developed through field monitoring in the Dayton metropolitan area, and (2) the Blueprint Columbus data set which focused on green infrastructure in several watersheds in the Clintonville neighborhood of Columbus, Ohio. Multi-family residential, commercial, and light industrial land uses had the largest (>25) TN:TP ratios, suggesting their runoff contributes to more toxic variations of algal blooms and that SCM retrofits in these watersheds should focus on N removal. Single-family residential, low-density residential, and heavy industrial had the most balanced TN:TP ratios, so runoff reduction to reduce overall nutrient load should be the focus of SCM retrofits in these watersheds. No significant changes to TN:TP ratio were observed after green infrastructure implementation or other infrastructure improvements (e.g., sanitary sewer lateral lining, downspout disconnection, and sump pump installation) in Columbus watersheds. As watersheds that received infrastructure retrofits were all single-family residential, no significant impact on N:P is not a negative result, suggesting retrofitted infrastructure removes N and P in a balanced manner.