Influence of polyphenols on low-loaded synthetic winery wastewater constructed wetland treatment with different plant species Available to Purchase

Synthetic wastewaters simulating physically pre-treated low-loaded winery effluents were treated for four months with five pilot-scale horizontal subsurface flow constructed wetlands (HSSF-CWs) using different plants. Species under study were Phragmites australis (HSSF-CW2), Lythrum salicaria (HSSF-CW3), Cladium mariscus (HSSF-CW4), and Iris pseudacorus (HSSF-CW5). The designation HSSF-CW1 was not planted, and was used as a control. The mean dissolved oxygen and oxidation  –  reduction potential values in all HSSF-CWs indicated anaerobic conditions in the bulk liquid. High pollutant-removal efficiencies were obtained. Apparently, the species with higher growth (Phragmites, Lythrum, and particularly Iris) improved total nitrogen (TN) and nitrogen as ammonium (N-NH₄⁺) removals, but adversely affected sulphate (SO₄²⁻) anaerobic reduction. Chemical oxygen demand (COD) removal efficiencies were high, although there were no clear indications how the kinds of plants might have influenced this parameter. A statistical analysis of variance indicated that only N-NH₄⁺ removal efficiencies were statistically different owing to the influence of the different plants. In a second 6 month experimental period, polyphenols (13  mg L⁻¹) were added to the synthetic wastewater to study possible inhibition effects. The addition of polyphenols did not seem to cause inhibition effects on COD, TN, and N-NH₄⁺ removals, but clearly negatively affected SO₄²⁻ removal. A new two-way analysis of variance confirmed that only SO₄²⁻ removal was negatively affected by polyphenols, while the effects of the different plants were only significant for N-NH₄⁺ removal. Polyphenols were nearly completely removed. First order rate constants obtained for COD, TN, SO₄²⁻, and polyphenol removals were similar to those reported by other authors.