Impact of an Integral Management System with Constructed Wetlands in Pig Slurry Traceability and GHG/NH3 Emissions

Abstract

The sustainable management of pig slurry (PS) in intensive farms is essential to reduce adverse environmental impacts and reduce the ecological footprint. If not managed properly, PS can release GHG/NH3 gases into the atmosphere and contaminate waters. This study evaluates the impact of an integral management system with physical and biological stages to mitigate the impact of PS. The system resulted in effective PS traceability, studying its physicochemical properties. The synergism in the whole system allowed a decrease in the most analyzed parameters during the autumn, spring, and summer. The pretreatment contributed significantly to obtaining an appreciable percentage of reduction in the constructed wetlands of SS (99–100%), COD (56–87%), TN (50–57%), and PO43− (88–100%). The emission values (g/m2/day) were 0–2.14 (CH4), 0–473.76 (CO2), 0–179.77 (H2O), 0–0.265 (N2O), and 0–0.195 (NH3), highlighting the raw, separated and manure fractions with the highest values. It is concluded that the system proves to be a practical, low-cost, and efficient technique for the treatment of PS. It significantly reduces the concentration of nutrients, and the intercepted byproducts can be valuable for application to the soil. In addition, the system effectively reduces GHG/NH3 emissions in decanted, purified, and wetland PS fractions.