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Winery wastewater treatment in a hybrid constructed wetland

Serrano, L., de la Varga, D., Ruiz, I., Soto, M.
Ecological engineering 2011 v.37 no.5 pp. 744-753
ammonium nitrogen, biochemical oxygen demand, chemical oxygen demand, constructed wetlands, mathematical models, nitrogen, pH, phosphates, sludge, temperature, wastewater, wastewater treatment
A full-scale hybrid constructed wetland (CW) was built to treat mixed effluent derived from a winery and tourist establishment. The treatment system consisted of a hydrolytic upflow sludge bed (HUSB) digester for suspended-solids removal, a vertical-flow (VF) constructed wetland and three parallel subsurface horizontal-flow (HF) constructed wetlands. The HUSB reduced TSS loads to 72–172mgL⁻¹, helping to prevent clogging, while organic loads for the wastewater entering the VF ranged from 422 to 2178mgCODL⁻¹ and from 216 to 1379mgBOD₅L⁻¹. At an average hydraulic loading rate (HLR) of 19.5mmd⁻¹ and average surface loading rates (SLR) of 30.4gCODm⁻²d⁻¹ and 18.4gBOD₅m⁻²d⁻¹, the overall VF+HF CW system reached average removal efficiencies of 86.8% of TSS, 73.3% of COD, and 74.2% of BOD₅. The system also removed 52.4% of total Kjeldhal nitrogen (TKN), 55.4% of NH₃-N and 17.4% of phosphates. While the VF unit showed high removal rates, the HF unit operated at lower removal rates than those previously reported. The CW units showed rapid adaptation to low pH values. A linear-regression analysis indicated that the independent variables SLR and temperature determined more than 95% of the variation in performance and efficiency of the CW system and offered simple mathematical models for design and system-description purposes.