water Article The Efficiency and Reliability of Pollutant Removal in a Hybrid Constructed Wetland with Common Reed, Manna Grass, and Virginia Mallow Michał Marzec *, Krzysztof Jó´zwiakowski,Anna D˛ebska,Magdalena Gizi ´nska-Górna, Aneta Pytka-Woszczyło, Alina Kowalczyk-Ju´skoand Agnieszka Listosz Department of Environmental Engineering and Geodesy, University of Life Sciences in Lublin, Lublin 20-950, Poland;
[email protected] (K.J.);
[email protected] (A.D.);
[email protected] (M.G.-G.);
[email protected] (A.P.-W.);
[email protected] (A.K.-J.);
[email protected] (A.L.) * Correspondence:
[email protected] Received: 10 July 2018; Accepted: 10 October 2018; Published: 13 October 2018 Abstract: In this paper, the pollutant removal efficiency and the reliability of a vertical and horizontal flow hybrid constructed wetland (CW) planted with common reed, manna grass, and Virginia mallow were analyzed. The wastewater treatment plant, located in south-eastern Poland, treated domestic sewage at an average flow rate of 2.5 m3/d. The tests were carried out during five years of its operation (2014–2018). The following parameters were measured: biochemical oxygen demand (BOD5), chemical oxygen demand (COD), total suspended solids, total nitrogen, and total phosphorus. The results showed that more than 95% of BOD5, COD, and total phosphorus was removed in the tested CW system. The average effectiveness of removal of total suspended solids and total nitrogen exceeded 86%. A reliability analysis performed using the Weibull probability model showed that the removal reliability in the tested CW was very high for BOD5, COD, total suspended solids, and total phosphorus (100%).