Technical Abstract: Confined animal production generates enormous per-unit-area quantities of waste. Wastewater from dairy and swine operations has been successfully treated in constructed wetlands. Wetlands normally have sufficient denitrifying microbial population, C sources, and anaerobic conditions to promote denitrification processes. However, when very high mass removal of N and P is required, pre- or in-wetland procedures that promote oxidation and nitrification are needed to increase treatment efficiency. Such procedures offer the greatest potential for improved treatment capacity of constructed wetlands. An overland flow treatment removed 59% of N applied in swine wastewater at a 50-kg/ha/d rate. A media filter treatment transformed up to 32% of the inflow total N into nitrate when wastewater was recycled four times. Immobilization of nitrifying microorganisms in polymer pellets resulted in faster nitrification rates and smaller reactors. The rate of nitrification using these pellets was 600 g of ammonia-N/cubic m/d. Solids removal prior to wetlands treatment is also essential for long-term functionality. When wetlands were combined with grass filter strips, an application of swine wastewater containing 14 kg/ha/day of N was treated to over 95% N removal. Polyacrylamide is effective for separating nutrients before the waste enters typical lagoon treatment. Low rates (25-100 mg/L) removed 80% of suspended solids, organic N, and organic P from swine flushing effluents.