Evapotranspirative systems (ETS) have no discharge and enable on-site wastewater treatment and reuse for biomass production. In order to increase performance of ETS under sub-Mediterranean climate with irregular and high precipitation ()1500 mm yr-1) structural modifications of the pilot ETS were implemented in the present study; namely a layer of clay was integrated just below the top soil layer of the system. The pilot ETS consisted of nine test beds where water quality parameters and water levels were measured weekly along with the amount of inflow water and precipitation. The modification enabled reduction of the precipitation entering the system thus increasing the hydraulic capacity for wastewater loading. The pilot ETS was planted with three different clones of white willow. In the first vegetative period the evapotranspiration and the biomass production were low (499-560 mm and 3.2-4.4 t DM ha–1, respectively) but they increased significantly during the second season (1055-1282 mm and 34-38 t DM ha–1) and resulted in 3.2 to 3.9 kg of biomass yield/m3 wastewater. The willows growing in the ETS outgrew significantly the control trees outside the system due to constant availability of nutrients and water in the system.
COBISS.SI-ID: 5511787
Willow clones used in evapotranspirative system (ETS) may significantly affect the performance of ETS; therefore, the clones with high biomass production and resilience to permanent flooding, increased nutrient concentrations, and salinity must be selected. In the presented study, a 27 m2 pilot ETS was set up in November 2015, enabling the testing of three different willow clones of Salix alba (L.): indigenous white willow 'V 160' (Salix alba) and two of its hybrids: 'V 052' (Salix alba var. calva x S. alba) and 'V 093' (Salix alba x S. alba var. vitellina) x S. alba . The stem height, diameter, and number of shoots per stump were measured weekly in the first year of growth on site, along with the water quality parameters and water levels in the test beds. There were no statistically significant differences in stem height and stem diameter between the three tested clones at the end of the vegetation season; however, the indigenous clone indicated better adaptability to conditions in ETS but somewhat lower biomass production in comparison to the hybrids. For all clones, the willows growing in the ETS outgrew the control willows, showing the positive effects of high water availability and wastewater on willow growth. Investigations in the following vegetation season will further evaluate the water demand and the biomass yield, estimate the efficiency of nutrient transfer from wastewater to wood biomass, and define the differences for the selected clones.
COBISS.SI-ID: 4877222
Pilot evapotranspirative willow system (ETS) was set up and investigated under sub-Mediterranean climates with high precipitation. ETSs enable reuse of domestic wastewater on site without discharge. In order to mitigate the impact of precipitation the ETS was equipped with drainage system to divert away the rainwater. The surface of the ETS bed was inclined and a clay layer, 10 cm below the bed surface was set to divert the excess rainwater to a collection pipe at the lowest point of the surface. Start-up monitoring of precipitation, rainwater drainage, water level in the ETS, soil water content, reference evapotranspiration and physical and chemical parameters of water in the ETS was carried out. The results showed high water level in ETS which was influenced by rain events. The drainage layer effectively drained 18% of the total precipitation fallen to the pilot plant. Soil water content was the highest in the root zone indicating water lift to compensate water losses due to transpiration. The results indicate that first vegetation season can be critical for the performance of ETS, since willow evapotranspiration capacity is not fully developed. Further investigation is being carried out in order to define the hydraulic capacity of ETS.
COBISS.SI-ID: 5113451
Evapotranspirative willow system (ETS) is a zero-discharge wastewater treatment system where all influent water is used for growth of willows and evaporation. The ETS has no pollutant emissions to the environment and enables reuse of water and nutrients i.e. closing material flows. Three different willow clones from the Croatian selection were tested on a pilot ETS, namely 'V 052' (Salix alba var. calva x S. alba), 'V 093' (Salix alba x S. alba var. vitellina) x S. alba and 'V 160' (Salix alba) in three parallels. Stem height, diameter and number of shoots per stump were measured weekly in the first year of growth on site, along with water quality parameters and water level in the experimental beds during the start-up operation. There were no differences in stem height between the experimental clones; however, 'V 052' and 'V 093' have 0.16 and 0.26 m higher stems in control plots compared to the experimental ones, while 'V 160' experimental plants were in average 0.20 m higher compared to control ones. Experimental 'V 160' also developed more shoots compared to the controls and had significantly higher water demand. Between the examined clones, so far 'V 160' presents the most appropriate clone for the use in ETS; however further investigation will evaluate the efficiency of nutrient transfer from wastewater to wood biomass, water demand and the biomass yield for the selected clones.
COBISS.SI-ID: 5101675
Access to adequate water and sanitation services is essential for good individual and population health. People served by small-scale systems in rural areas and small towns have the right to the same level of health protection as others. Goals 3 and 6 of the 2030 Agenda for Sustainable Devel-opment call for combating of waterborne diseases and for ensuring universal and equitable access to both safe drinking-water and adequate sanitation for all by 2030. To achieve universal access, due attention needs to be paid to the particularities and challenges that may impair the provision of safe and sustainable services by small-scale water supply and sanitation systems. Improving the situation of such systems is a priority area under the Protocol on Water and Health to the 1992 Convention on the Protection and Use of Transboundary Watercourses and International Lakes. This publication was developed under the Protocol; it aims to support effective policy action and pro¬mote good practices for creating an enabling environment in which to improve the situation of small-scale systems. It introduces a variety of tools that are available to policy-makers and highlights how these can be tailored to the particularities of small-scale systems. It also presents a number of case studies that illustrate how countries have taken the initiative to improve the situation of small systems.
COBISS.SI-ID: 5169259