Assessment of the technological reliability of a hybrid constructed wetland for wastewater treatment in a mountain eco-tourist farm in Poland

Abstract

The aimof the present studywas to assess the technological reliability of a domestic hybridwastewater treatment installation consisting of a classic three-chambered (volume 6 m3) septic tank, a vertical flow trickling bed filled with granules of a calcinated clay material (KERAMZYT), a special wetland bed constructed on a slope, and a permeable pond used as a receiver. The test treatment plantwas located at amountain eco-tourist farm on the periphery of the spamunicipality of Krynica-Zdrój, Poland. The plant's operational reliability in reducing the concentration of organicmatter, measured as biochemical oxygen demand (BOD5) and chemical oxygen demand (COD),was 100%whenmodelled by both theWeibull and the lognormal distributions. The respective reliability values for total nitrogen removal were 76.8% and 77.0%, total suspended solids-99.5% and 92.6%, and PO4-P-98.2% and 95.2%, with the differences being negligible. The installation was characterized by a very high level of technological reliability when compared with other solutions of this type. The Weibull method employed for statistical evaluation of technological reliability can also be used for comparison purposes. Fromthe ecological perspective, the facility presented in the study has proven to be an effective tool for protecting local aquifer areas.