State of the art for animal wastewater treatment in constructed wetlands

• Published in: Water science and technology 2001-01, Vol.44 (11-12), p.19-25
• Main Authors: Hunt, P.G, Poach, M.E
• Format: Article
• Language: English
• Subjects: Agricultural wastes; Anaerobic conditions; Anaerobic microorganisms; Animal production; Animals; Anoxic conditions; Applied sciences; Aquatic plants; Artificial wetlands; Bacteria, Anaerobic - physiology; bioaccumulation; Biodegradation, Environmental; Biological and medical sciences; Biological treatment of waters; Biotechnology; carbon; case studies; cattle manure; Conservation of Natural Resources; constructed wetlands; dairy cattle; Dairy industry wastewaters; Denitrification; Ecosystem; Environment and pollution; Exact sciences and technology; Freshwater plants; Fundamental and applied biological sciences. Psychology; Geologic Sediments; Industrial applications and implications. Economical aspects; Manure; Marshes; Microorganisms; Mineral nutrients; Nitrification; nitrogen; Nitrogen - metabolism; Nutrient transport; Nutrient uptake; nutrients; Other wastewaters; overland flow; Oxidation; Oxidation-Reduction; Oxygen; Pathogens; Phosphorus; Phosphorus - metabolism; Phosphorus removal; pig manure; Plants; Pollution; ponds; Procedures; Refuse Disposal - methods; Removal; Sediments; Soil Microbiology; solids; Swine; Uptake; Wastewater; Wastewater treatment; Wastewaters; Water Microbiology; Water treatment and pollution; wetland plants; Wetlands
• ISSN: 0273-1223; 1996-9732
• DOI: 10.2166/wst.2001.0805

Although confined animal production generates enormous per-unit-area quantities of waste, wastewater from dairy and swine operations has been successfully treated in constructed wetlands. However, solids removal prior to wetland treatment is essential for long-term functionality. Plants are an integral part of wetlands; cattails and bulrushes are commonly used in constructed wetlands for nutrient uptake, surface area, and oxygen transport to sediment. Improved oxidation and nitrification may also be obtained by the use of the open water of marsh-pond-marsh designed wetlands. Wetlands normally have sufficient denitrifying population to produce enzymes, carbon to provide microbial energy, and anaerobic conditions to promote denitrification. However, the anaerobic conditions of wetland sediments limit the rate of nitrification. Thus, denitrification of animal wastewaters in wetlands is generally nitrate-limited. Wetlands are also helpful in reducing pathogen microorganisms. On the other hand, phosphorus removal is somewhat limited by the anaerobic conditions of wetlands. Therefore, when very high mass removals of nitrogen and phosphorus are required, pre- or in-wetland procedures that promote oxidation are needed to increase treatment efficiency. Such procedures offer potential for enhanced constructed wetland treatment of animal wastewater.