Constructed Wetlands for agro-food industries

Wastewater produced by agro-alimentary activities are often characterized by a high content of organic matter, grease and nutrients (nitrogen and phosphorus) and sometimes by high salinity, and by strong seasonal fluctuations in term of quantity and chemical-physical characteristics.

Because of this, its depuration treatment requests particular attention and accurate evaluation of every technical solution available. As one of the most successful application it can be noted the winery industry: in Italy this sector consists in many hundreds of small producers, whose scarce production and relatively low annual budgets don't allow to choose advanced technological treatments for the depuration of wastewater, so creating big problems in respect of the most recent laws concerning industrial wastewater (law n. 152/99). Constructed wetland (CW) offers an effective solution with low costs of realization and management and low energy consumption.

Constructed wetland removal efficiencies

IRIDRA has designed among the first and most relevant CWs for the treatment of wastewater from agri-food industries in Italy, following also the monitoring phases. Regarding wineries, IRIDRA was worldwide the first firm that designed and supervised the construction of a CW for a winery at full scale. The CW treatment plants serving the wineries of Cecchi, Ornellaia and Zari are in operation since 2001 and were monitored in collaboration with ARPAT. CW systems for winery wastewater treatment shown high organic removal efficiencies with hydraulic retention times of 3-4 days: COD 87-98%, BOD5 92-98%, Suspend Solids 70-90%, Total Nitrogen 50-90%, Total Phosphorous 20-60%. These ranges were confirmed by following research studies (Rochard et al., 2002, Müller et al., 2002, Zanieri et al, 2010, Masi et al 2015).

IRIDRA's experience

IRIDRA still maintains its leadership in the field of nature-based solutions for wineries, continue to propose and monitor novel CW techniques for his particular application (e.g., french systems for raw wastewater, aerated wetlands, or sludge drying reed beds).

One example is the CW serving the winery Cecchi&Sons sited in Castellina in Chianti, which currently treats about 100 m3/d produced by bottling activities and by offices. The CW has the following scheme: 1st stage FRB, 2nd stage HF, 3rd stage FWS. The CW WWTP respects the water quality standard set by Italian law for industrial wastewater.

Another relevant example is the CW WWTP of Ornellaia winery, sited in Bolgheri and currently treating about 40 m3/d of winery wastewater produced by vintage and bottling. The WWTP is a hybrid multi-stage CW, respecting the water quality standard set by Italian law for discharge in the water body.

IRIDRA had also successful applications with dairy wastewater treatment. One example is the CW WWTP for the Fattoria della Piana dairy, which treats about 100 m3/d of dairy wastewater, discharging in the water body.

IRIDRA's authors are highlighted in bold.

Masi, F., Rizzo, A. and Bresciani, R., Treatment of Wineries and Breweries Effluents using Constructed Wetlands, in "Constructed Wetlands for Industrial Wastewater Treatment", Stefanakis A. (Ed.), Wiley, 95-104; 978-1-119-26834-5, 2018.

Masi, F., Rochereau, J., Troesch, S., Ruiz, I., & Soto, M. (2015). Wineries wastewater treatment by constructed wetlands: a review. Water Science and Technology, 71(8), 1113-1127.

Masi F., Rizzo A., Bresciani R., Basile C., Dairy Wastewater Treatment by a Horizontal Subsurface Flow Constructed Wetland in Southern Italy, in "Natural and Constructed wetlands: Nutrients, heavy metal, energy cycling, and flow", Vymazal Jan (Ed.), Springer, 131-139; 978-3-319-38926-4, 2016.

Müller D.H., Dobelmann J.K., Hahn H., Pollatz T., Romanski K., Coppik L. (2002), “The application of constructed wetlands to effluent purification in wineries”. Proceedings of the 8th International Conference on Wetland Systems for Water Pollution Control, 16-19 September 2002; IWA Publishing and University of Dar El Salaam: Arusha, Tanzania, pp. 599-605.

Rochard J., Mouton-Ferrier V., Kaiser A. Solomon N. (2002) The application of constructed wetlands in the viticultural sector: Experimentation on a winery effluent treatment device. Proceedings of the 8th International Conference on Wetland System for Water Pollution Control, 16-19 September 2002; IWA Publishing and University of Dar El Salaam: Arusha, Tanzania, pp. 494-503.

Zanieri L., Bracali M., Bresciani R. and Masi F., “Multi-stage CW systems for winery wastewater treatment”, submitted to WP&T, March 2011, Atti della "12th IWA Specialized Group Conference on "Wetland Systems for Water Pollution Control", 4-8 Ottobre 2010, Venezia, Italia