Assessment of pre-digested piggery wastewater treatment operations with surface flow integrated constructed wetland systems.
Non-point source pollution such as land-spreading of nitrogen-rich piggery wastewater poses a significant threat to surface waters. The aim was to examine the treatment of anaerobically digested piggery wastewater using four different meso-scale integrated constructed wetland (ICW) systems planted with Glyceria maxima. Four replicates were used for each system to assess differences due to nutrient loading, hydraulic loading and effluent recycling. All systems were effective in removing total organic nitrogen, ammonia-nitrogen, nitrate-nitrogen and molybdate reactive phosphorus. However, ammonia-nitrogen removal was the greatest challenge for high flow rates (>100 m(3)/ha/d). Nitrification was higher in summer than winter. Findings show for the first time that effluent recycling within ICW was beneficial to lower ammonia-nitrogen but was associated with higher operational costs. The cost-benefit ratio based on ammonia-nitrogen removal for standard, recycling, high nutrients and high flow rate treatments was 1.08:1.04:1.06:1.00. It follows that a high flow rate was only marginally more cost-effective.
Harrington
Caolan
C
Institute for Infrastructure and Environment, School of Engineering and Electronics, The University of Edinburgh, William Rankine Building, The King's Buildings, Edinburgh EH9 3JL, Scotland, United Kingdom.
Scholz
Miklas
M
D000818:Animals; D007220:Industrial Waste / Q000517:prevention & control*; D012212:Rheology / Q000379:methods*; D013552:Swine; D018511:Systems Integration; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*; D018508:Water Purification / Q000379:methods*; D053833:Wetlands
D007220:Industrial Waste; D014874:Water Pollutants, Chemical