Design and performance of hybrid constructed wetland systems for high-content wastewater treatment in the cold climate of Hokkaido, northern Japan

Abstract

The performance of six multistage hybrid constructed wetland systems was evaluated. The systems were designed to treat four kinds of high-content wastewater: dairy wastewater (three systems, average inflow content 2,400-5,000 mg·COD l(-1), 3-6 years of operation); pig farm wastewater, including liquid food washing wastewater (one system, 9,500 mg·COD l(-1), 3 years); potato starch processing wastewater (one system, 20,000-60,000 mg·COD l(-1), 3 years); and wastewater containing pig farm swine urine (one system, 6,600 mg·COD l(-1), 2.8 years) (COD = chemical oxygen demand). The systems contained three or four vertical (V) flow beds with self-priming siphons and surface partitions and no or one horizontal (H) flow bed (three to five beds). In some V flow beds, treated effluents were recirculated (Vr) through the inlet to improve performance. Mean annual temperature was 5-8 °C at all locations. To overcome clogging due to the high load in a cold climate, we applied a safety bypass structure and floating cover material to the V flow beds. Calculated average oxygen transfer rates (OTRs) increased proportionally with the influent load, and the OTR value was Vr > V> H. The relations of load-OTR, COD-ammonium, and a Arrhenius temperature-dependent equation enable the basic design of a reed bed system.

Long term treatment performance of constructed wetlands for wastewater treatment in mountain areas: Four case studies from the Czech Republic

“…However, the field experience has indicated that plants can grow well and filtration bed does not freeze in high altitude locations (Navara, 1996;Merlin et al, 2002;Züst and Schönborn, 2003). This fact was also observed under northern latitude conditions such as in USA (Minnesota, Vermont, California), Norway, Canada or Northern Japan (e.g., Reuter et al, 1992;Kadlec et al, 2003;Mander and Jenssen, 2003;Muňoz et al, 2006;Giaever, 2003;McCarey et al, 2004;Yates et al, 2012;Kato et al, 2013).…”

Treatment of Combined Dairy and Domestic Wastewater with Constructed Wetland System in Sicily (Italy). Pollutant Removal Efficiency and Effect of Vegetation

“…In Japan, multistage HSSF systems were designed to treat DWW under cold climate conditions. Researchers found high removal rates for COD RE (93-96.00%) [55]. In southern Europe, in various studies [12,[27][28][29][31][32][33], the authors reported average values of BOD 5 RE ranging between 70% and 94% depending on various factors, such as the size of the CW and the wastewater pretreatment.…”

Analyzing the Removal Effect of Nitrogen before and after Enhanced Aeration in Constructed Wetlands

“…However, the wastewater removal effect of major pollution in a constructed wetland would decrease in quite a few cold districts [9][10]. Therefore, some methods have been applied for solving the bottleneck problems [11].…”