## 1 Introduction  
Dairy farms, with individual lactating cows producing an average of 45-55 kg of manure per day, output high amounts of manure typically applied to surrounding land [1]. This can be an acute source of nitrate and bacterial loads, which is a concern in terms of environmental impacts (i.e., eutrophication, greenhouse gas (GHG) emissions) but can also be a concern for the health of the cattle themselves [2]. In combination with high nitrate loads from surrounding croplands via synthetic fertilizers, nitrate and bacteria from manure can seep into groundwater, which is the main drinking water source for dairy cattle, collected via wells and dispensed in troughs. There is a lack of regulatory guidelines surrounding acceptable levels of nitrate and bacteria in dairy cattle drinking water (except for grade A daixies, which regulate that fecal coliform remain below zero in cattle drinking water) [3,4]. In general, USDA grade standards for dairies are optional, and it indicates that the milk production and processing is performed under stringent sanitation standards. Studies have shown that high levels of nitrate can lead to troubled breathing, infertility issues, and decreased milk production in cattle, and bacterial contamination can lead to diseases such as leptospirosis and brush-cellosis [5, 6, 7]. In addition to negatively impacting cattle health, decreased water quality can also indirectly reduce milk production by causing cattle to drink less water, which is a large factor in milk production volume [8]. In addition to a lack of contaminant regulations and widespread monitoring, there is a shortage of point-of-use treatment options available for reducing nitrate and bacteria levels in trough water. In general, a point-of-use water treatment system offers the water treatment at a specific location, where the water is being used. As an example, a point-of-use system for a faucet will treat only the water drawn from the faucet rather than the entire water supply. Often, point-of-use water treatment systems based on the reverse osmosis (RO) process are used to treat water at a single fixture/point. Treatment options such as UV light, raking/dredging, and fish are algaecides known to control algae growth in drinking water; however, these systems are yet to be tested for livestock drinking water. Some of the treatment and prevention techniques for bacteria include the use of chemical disinfectants and frequent trough cleaning [9]. For nitrate, there are even fewer treatment options, with the primary recommendation to direct cattle to an alternative water source, which is not usually feasible for groundwater-sourced drinking water [10]. Long-term prevention options for nitrate exist in the form of manure management strategies, which decrease nitrate loads into groundwater, but with the trend of increasing farm size and nitrates persisting in groundwater for up to decades, there still exists a need for point-of-use treatment [11]. Traditional options such as slow sand filtration (SSF), constructed wetlands (CW), and artificial groundwater recharge (AGR) are used for controlling the transport of contaminants into water bodies. As an example, SSF uses a sand bed to remove pathogenic bacteria, turbidity, and suspended particles. SSF is considered to be a cost-effective option for controlling the pollution in drinking water. In constructed wetland systems, wastewater is treated by wetland plants, microbes, and soil filters. In addition, AGR systems are based on spreading water on the larger land area for improving infiltration into the soil, which assists in restoring groundwater and controlling the contaminant transport into groundwater. While these are effective options, the scale is an issue for many locations. For example, these systems require a larger area and an extended period of time for treating the water, and it could be challenging to implement these treatment systems in dairy farms.