# Water and Wastewater Management in Agriculture
## 3 Conclusions  
Agriculture and modern farming methods, in particular, require reliable access to water of adequate quality. Climate change is increasingly restricting this access. It is therefore necessary to look for alternative sources of water. In addition to groundwater and surface water, retained rainwater is playing an increasingly important role. Conventional rainwater drainage systems, which are designed to transport rainwater to the recipient via the shortest route, are being extended with systems for cleaning and collecting rainwater in order to use it for irrigating crops, especially covered areas. It is equally important to use the collected water as rationally as possible. Two articles in the Special Issue deal with this topic. The first concerns assessing the quality of rainwater with a view to its use in the national park, and the second is concerned with the use of intermittent irrigation in protected cultivation using an automatic irrigation system. At the same time, extensive efforts have been made in the EU to reuse treated wastewater in agriculture. This applies in particular to wastewater from domestic wastewater treatment plants and from the industry, where there is no risk of wastewater being contaminated with hazardous substances. Under the current EU legislation, they must undergo additional treatment, including membrane processes and disinfection. An equally important source of wastewater that can be treated as a potential source of water for crops under cover is the wastewater produced by soilless cultivation facilities. Treated, e.g., in electrochemical and electrobiological reactors with connected biomass, it can be purified in membrane reactors and, after disinfection, it is reused to produce a nutrient solution that is used in soilless crops for irrigation and fertilization. This significantly reduces water consumption in this type of system. Three articles are dedicated to the application of electrochemical and electrochemical methods, two of which concern wastewater from soilless tomato cultivation and one concerning the removal of dyes. The removal of dyes from agricultural wastewater generated in fruit and vegetable collection and processing plants is an important environmental issue, as the coloration of surface waters caused by the discharge of colored wastewater into receiving waters can lead to the impairment of the photosynthesis process. Three papers are devoted to the removal of dyes, including two on the use of waste from agricultural production, such as rapeseed, hulls, exoskeletons, and molts of farmed mealworms. Another topic is the use of agricultural wastewater for the production of microalgae, which is later used as a food source for geese and ducks for example. This use of agricultural wastewater is presented in one of the articles. Organic waste from agriculture and sewage sludge from wastewater treatment plants that have previously undergone a stabilization process are often used in agriculture as fertilizers or soil conditioners. This is associated with environmental problems, such as changes in biological soil properties and heavy metal contamination in soil and water bodies. These problems are dealt with in four articles. Surface waters are the final consumers of pollution associated with agriculture and aquaculture. Lakes and other water bodies are particularly susceptible to degradation. This is reflected in the quality of water in reservoirs and the quantity and quality of bottom sediments. In addition to measures to reduce the input of pollutants from agricultural catchment areas into receiving waters, remediation measures must be implemented, e.g., multi-point aeration or hypolimnetic abstraction. These problems are dealt with in two articles. Today's agriculture and aquaculture are characterised by the high consumption of environmental resources, especially water, and the increasing destruction of natural ecosystems.