Ammonium removal from a fertilizer factory wastewater.

SANCHEZ, G.C.; MAINE, M.A.; HADAD H.R.; CAFFARATTI, S.E.; PEDRO, M.C.; DI LUCA, G.A.; MUFARREGE, M.M.; CAMAÑO SILVESTRINI, N.E.

YORK

Simposio; 6th International Symposium on Wetland Pollutant Dynamics and Control. Constructed Wetland Association. WETPOL; 2015

Cranfield University-CWA-WETPOL

Wastewater from a fertilizer factory requires treatment to remove nitrogen compounds prior to environmental disposal. Constructed wetlands can be a good solution to nitrogen removal. There are thousands of wetlands in operation worldwide for the treatment of different effluents. However, in Argentina this technology is poorly implemented. The aim of this study was to evaluate the feasibility of using wetland systems for the treatment of an alkaline effluent with high concentrations of ammonium from this fertilizer factory. Batch reactors simulating microcosm-scale horizontal subsurface flow wetlands (HSSFW) (0.25 x 0.4 x 0.40 m) and free water surface wetlands (FWSW) (0.25 x 0.4 x 0.60 m) were disposed. Different substrates and different macrophytes were evaluated. HSSFW were filled with 0.35 m of gravel or light expanded clay aggregates (Leca 10/20) and planted with Iris pseudacorus (yellow lily), Canna indica (indian shot) and Typha domingensis (cattail). Unplanted HSSFW were also disposed. FWSW with 0.25 m of loamy sediment, unplanted and planted with T. domingensis were disposed. The wastewater was added to a height of 0.3 m above the sediment. T. domingensis was chosen due to it is the dominant species in the pond that exists in the studied factory. Reactors were fed with real wastewater from the fertilizer factory. In all cases, the hydraulic residence time was 7 days. Evapotranspiration was measured and compensated. pH, NH4+ and NO3- were measured as described in APHA (1998) in the wastewater before and after the treatment in each reactor. Experiment lasted three months. The different wetlands with different substrates and macrophytes were efficient in the treatment of effluent obtaining ammonium removals higher than 80%. The best performance was obtained with the HSSFW with Leca planted with different macrophytes. The different macrophyte species did not present significant differences in ammonium removal efficiency in HSSFW. T. domingensis showed the highest productivity while C. indica has high aerial part biomass, presenting the advantage of being an ornamental species.FWSW presented a satisfactory performance. In Argentina, FWSW are of special interest due to their easy operation and maintenance and the usual large availability of land around the factories.