Tolerance to hydraulic and organic load fluctuations in constructed wetlands

Abstract

This paper describes a two-year performance evaluation of four different constructed wetland (CW) treatment systems designed by IRIDRA Srl, located in central Italy. All four CW systems were established to treat wastewater effluent from different tourist activities: (1) one single-stage CW for secondary treatment of domestic wastewater (30 p.e.) at a holiday farm site; (2) a hybrid compact system consisting of two stages, a horizontal flow (HF) system followed by a vertical flow (VF) system for the secondary treatment of effluent from a 140 p.e. tourist resort; (3) a single-stage vertical flow (VF) CW for a 100 p.e. mountain shelter; and (4) a pair of single-stage, HF CWs for the secondary treatment of segregated grey and black water produced by an 80 p.e. camping site. These tourism facilities are located in remote areas and share some common characteristics concerning their water management: they have high variability of water consumption and wastewater flow, depending on the season, weather and weekly regularities; they have no connection to a public sewer and most sites are located in a sensitive environment. Total suspended solids (TSS), chemical oxygen demand (COD), biochemical oxygen demand (BOD5), ammonium (N-NH4+), nitrate (N-NOx), total nitrogen (Ntot), total phosphorus (Ptot), total coliform (TC), faecal coliform (FC), E. coli removal efficiencies for all four CW systems are presented. The results from this study demonstrate the potential of CWs as a suitable technology for treating wastewater from tourism facilities in remote areas. A very efficient COD reduction (83-95%) and pathogen elimination (3-5 logs) have been achieved. Furthermore, the CWs are easily maintained, robust (not sensitive to peak flows), constructed with local materials, and operate with relatively low cost.

Greywater treatment as an option for effective wastewater management in small communities

“…This is probably due to the concentrating effect obtained with the various water saving measures in operation resulting in an average influent concentrations three times higher then measured at the other places. [22] Table 3 shows the removal efficiencies for COD, TN and NH 4 -N for the different set-ups, as well as the average feed and permeate concentrations over the operation period. Each cycle time reduction of the SM-SBR enhanced the removal efficiency and with an HRT of 8h a first optimised cycle time seems to be reached.…”

Effectiveness of pollutants removal in hybrid constructed wetlands – different configurations case study

“…Pollutants concentrations in wastewater in analysed hybrid constructed wetlands are higher than the most commonly occurring in other European countries. The quality of influent wastewater is comparable with raw wastewater without pretreatment (France) [2,6,7,12,13].…”

“…On the other hand, SSHF wetlands operate mostly under anoxic/anaerobic conditions due to the permanent saturation of the bed, which makes it a likely environment for denitrification. SSHF beds are also responsible for effective suspended solids and organic matter removal [4,5,7].…”

Pharmaceuticals and Personal Care Products (PPCPs) in the Environment and Their Removal from Wastewater through Constructed Wetlands

“…Indeed, constructed wetlands have been extensively used at full-scale across the world since the 80s, for the treatment of not only municipal wastewater but all kinds of wastewater including stormwater, landfill leachate, tannery wastewater, and other industrial wastewaters (Schulz et al, 2001;Behrends et al, 2007;Nivala et al, 2007;Vymazal, 2009). They have been widely implemented in countries like France (Molle et al, 2005), UK (Weedon, 2003;Cooper, 2005), Denmark (Brix and Arias, 2005) or Czech Republic (Vymazal, 2002), and their implementation is increasing in countries like Spain (Vera et al, 2011) or Italy (Masi et al, 2007). Numerous studies have shown their capability to maintain hydraulic, technical, economic, environmental and ecological benefits (Vymazal, 2002;Dixon et al, 2003;Zhou et al, 2009).…”