Permeable Organic Barriers as Effective Tools for Reducing Emissions of Nitrogen Compounds and PCBs from Manure to Groundwater

Agricultural pollution, such as contamination from manure storage or leaking livestock buildings, often spreads through the catchment, affecting groundwater and surface water. An effective solution is the construction of permeable organic barriers. This study evaluates the efficiency of an innovative bioactive barrier in removing nitrogen compounds (NO3− and NH4+) and polychlorinated biphenyls (PCBs). Two types of barriers were tested: a horizontal deposit under a manure storage point and a vertical deposit in the leachate flow path. The bioactivity of the barrier was confirmed by the presence of bacterial genes involved in nitrogen transformation and PCB degradation. Results showed a 70% reduction in NO3− (368.4 mg·L−1) and 43% reduction in NH4+ (42.4 mg·L−1). Genetic analysis identified bacteria capable of complete denitrification, resembling Pseudomonas stutzeri. The analysis also indicated that higher summer temperatures and pH levels fostered microbial communities capable of nitrogen transformation. Cluster analysis revealed that the vertical deposit zone was crucial for nitrogen removal. Additionally, the vertical barrier achieved a 53% reduction in PCBs, with Pseudomonas aeruginosa-like bacteria identified as PCB degraders.