Short-rotation willows as a wastewater treatment plant : biomass production and the fate of macronutrients and metals

Istenič, Darja (author), Božič, Gregor (author)

Evapotranspirative willow systems (EWS) are zero-discharge wastewater treatment plants that produce woody biomass and have no discharge to surface or groundwater bodies. The influence of wastewater on the growth of three clones of Salix alba (‘V 093’, ‘V 051’ and ‘V 160’) and the distribution of macronutrients and metals in a pilot EWS receiving primary treated municipal wastewater was studied under a sub-Mediterranean climate. The influent wastewater, shoot number, stem height, and biomass production at coppicing were monitored in two consecutive two-year rotations. Soil properties and the concentrations of macronutrients and metals in soil and woody biomass were analyzed after the first rotation. S. alba clones in EWS produced significantly more woody biomass compared to controls. ‘V 052’ produced the highest biomass yield in both rotations (38–59 t DM ha$^{−1}$) and had the highest nitrogen and phosphorus uptake (48% and 45%) from wastewater. Nitrogen and phosphorus uptake into the harvestable woody biomass was significantly higher in all clones studied compared to other plant-based wastewater treatment plants, indicating the nutrient recovery potential of EWS. The indigenous white willow clone ‘V 160’ had the lowest biomass yield but absorbed more nutrients from wastewater compared to ‘V 093’. Wastewater composition and load were consistent with the nutrient requirements of the willows; however, an increase in salinity was observed after only two years of operation, which could affect EWS efficiency and nutrient recovery in the long term.

• Language: English
• Keywords: evapotranspirative willow system, resource recovery, sustainable wastewater treatment, short rotation coppice
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: ZF - Faculty of Health Sciences; FGG - Faculty of Civil and Geodetic Engineering
• Publication status: Published
• Publication version: Version of Record
• Year: 2021
• Number of pages: 21 str.
• Numbering: Vol. 12, iss. 5, art. 554
• PID: 20.500.12556/RUL-126752
• UDC: 628.3:502.131.1
• ISSN on article: 1999-4907
• DOI: 10.3390/f12050554
• COBISS.SI-ID: 62017795
• Publication date in RUL: 05.05.2021

Record is a part of a journal

• Title: Forests
• Shortened title: Forests
• Publisher: MDPI
• ISSN: 1999-4907
• COBISS.SI-ID: 3872166

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.
• Licensing start date: 01.05.2021