Abstract
Constructed wetland (CW) is a popular sustainable best management practice for treating different wastewaters. While there are many articles on the removal of pollutants from different wastewaters, a comprehensive and critical review on the removal of pollutants other than nutrients that occur in agricultural field runoff and wastewater from animal facilities, including pesticides, insecticides, veterinary medicine, and antimicrobial-resistant genes are currently unavailable. Consequently, this paper summarized recent findings on the occurrence of such pollutants in the agricultural runoff water, their removal by different wetlands (surface flow, subsurface horizontal flow, subsurface vertical flow, and hybrid), and removal mechanisms, and analyzed the factors that affect the removal. The information is then used to highlight the current research gaps and needs for resilient and sustainable treatment systems. Factors, including contaminant property, aeration, type, and design of CWs, hydraulic parameters, substrate medium, and vegetation, impact the removal performance of the CWs. Hydraulic loading of 10–30 cm/d and hydraulic retention of 6–8 days were found to be optimal for the removal of agricultural pollutants from wetlands. The pollutants in agricultural wastewater, excluding nutrients and sediment, and their treatment utilizing different nature-based solutions, such as wetlands, are understudied, implying the need for more of such studies. This study reinforced the notion that wetlands are effective for treating agricultural wastewater (removal > 90%) but several research questions remain unanswered. More long-term research in the actual field utilizing environmentally relevant concentrations to seek actual impacts of weather, plants, substrates, hydrology, and other design parameters, such as aeration and layout of wetland cells on the removal of pollutants, are needed.
Highlights
Agricultural runoff contains excess quantities of diverse pollutants, such as sediments, nutrients, pathogens, veterinary medicines, pesticides, and metals
While much of the previous reviews focused on how Constructed wetland (CW) are used to efficiently remove nutrients, such as nitrogen and phosphorus, and sediments from wastewaters [21,22], this paper focuses on the occurrence of pollutants in the agricultural runoff and how this cost-effective green approach [23] can be used to remove pollutants from agricultural runoff for mitigation of the negative environmental impacts of agricultural intensification
The results showed that removal performance ranged from high to low in the order of subsurface vertical flow (SSVF)-Low water level > SSVF-High water level > subsurface horizontal flow (SSHF) > surface flow (SF) indicating that the various design, flow path and water level led to different antibiotic removal rates through impacting the parameters, such as temperature, oxygen transfer, oxidation-reduction potential, sorption sites, etc
Summary
Agricultural runoff contains excess quantities of diverse pollutants, such as sediments, nutrients, pathogens, veterinary medicines, pesticides, and metals. Approximately two million tons of pesticides were used globally in 2019, with China and the USA being the two major users [7] These chemicals are perfect for increasing yield but are ecologically detrimental when they leave agricultural ecosystems in runoff water following storms [8]. According to the Environmental Protection Agency (EPA), CECs include but are not limited to nanoparticles, pharmaceuticals, personal care products (PCPs), estrogenic compounds, flame-retardants, detergents, and other industrial chemicals. All of these contaminants, many of which have agricultural origin, significantly influence human health and aquatic life [15]. Constructed wetland (CW) is a natural ecological alternative to the conventional methods for treating various types of wastewater, including agricultural runoff [16]. Focus pollutants include veterinary medicines, antimicrobial resistant genes, insecticides, herbicides, and pesticides
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
