engleski

Ammonia removal from wastewaters of zagreb in a pilot scale constructed wetland

The article discusses the treatment of municipal waters of city of Zagreb by pilot scale constructed wetlands (PSCW) with horizontal subsurface flow during 2004. Particular attention is devoted to the macrophytes role in ammonia (NH4-N) removal from spring to late autumn in a moderate climate. PSCW is designated in three parallel lines of basins using river gravel as a substrate. Two lines of basins were planted with autochthonous hydrophitic macrophytes (Scirpus sylvaticus, Typha latifolia, Phragmites communis, Carex sp.) and control line was unplanted. The PSCW system is designed to all three lines be fed with equal influent discharge characterized by NH4-N concentrations of average 16 mg/L. The highest removal percentages of NH4-N were in planted basins (75-81%), towards 23% in the unplanted line, at the summer water temperatures (18-21oC). As the weather cools, treatment levels of PSCW decreased. The effluent values of NH4-N from planted lines, but not from unplanted line, were through the all investigated period within the permit limits of Croatian Standards for discharging effluents in the surface waters of second class.

ammonia; constructed wetland; continental climate; municipal wastewater

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