From a global perspective, drought is a well-known manifestation of climate change. The search for alternative sources of water also brings uncertainties and risks, for example, in relation to wastewater irrigation. We asked ourselves whether and how supplemental irrigation with pre-treated wastewater would affect the subsoil or groundwater quality. We constructed semi-operational models that were loaded with wastewater in a controlled manner over three years of observations. Ammonium nitrogen (NH4+-N) pollution is one of the monitored parameters in wastewater discharge. In specific situations and under strict operating conditions, it can be assumed that ammonia nitrogen may not be a significant problem for groundwater. Already at a depth of 0.5 m below ground level, the average nitrogen levels are below 0.02 mg/L at an irrigation rate of approximately 15.5 mm/day. When monitoring total phosphorus (TP), these values are reduced with more variability—depending on the plant species at the surface, ranging from 0.17 to 0.95 mg/L. The measured values are used to calibrate the numerical model, or to determine the reaction parameters that enter the governing equation to describe the distribution of the solution in the soil environment. The results show an acceptable compliance between the model and real measurements, it will be possible to use them in practice for the design of wastewater irrigation systems.
In recent years, natural wastewater treatment wetland plants have been gaining more attention from researchers and the public due to their low operating costs and efficient way of treating wastewater. Treatment wetland plants with pulse-fed vertical flow filters are one of the most efficient treatment technologies. For optimum operation, intermittent loading of wastewater onto the filter surface is necessary, for which various types of automatic siphons can be used in addition to pumps. This kind of automatic siphons do not require electricity for their operation. The aim of the actual measurements was to specify the hydraulic characteristics of four different types of automatic siphons used in France, Germany, and the Czech Republic. In the course of the laboratory measurements, it was possible to define the basic hydraulic characteristics of the different technical solutions - e.g. maximum water flow, starting and shut-off water level, emptying rate and discharge flow. The measured values then lead to the determination of the total hydraulic losses of the device, while the limits and nature of the individual solutions are shown in comparison with each other. The results can be used for the design of the downstream hydraulic system of the distribution piping that is spread over the filter surface.
The main objective of the paper is to contribute to practical applicability of the CBA in the agricultural sector by exploring the chances to estimate Czech social values of selected agricultural commodities using available statistical data. More specifically, we try to analyse for which commodities secondary data sets are available from which we may deduce the estimates of shadow price ratios, then to estimate SPRs for selected agricultural commodities and to analyse and discuss the applicability of such estimates in practical appraisal with respect to theoretically ideal measures and resulting available measures as well as with respect to the situation in which the CBA analyst typically is. We selected the following commodities: poultry, pigs, bulls, milk, rapeseed, maize, barley and wheat as items more suitable for SPR estimates mostly because of the data availability and the internal homogeneity of the items, which was closer to the theoretically required values than for other commodities. Under additional simplifying assumptions, we estimated SPR proxies for the particular commodities and finally summarized the pros and cons for application of SPR alternatives.
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