# Water and Wastewater Management in Agriculture
## 2 An Overview of Published Articles
Similarly to the first article (contribution 3), the third article investigates the effectiveness of electrochemical and biological methods for treating industrial wastewater containing low concentrations of critical dyes, specifically a mixture of acid violet 90 (AV90) and acid red 357 (AR357) in Na\({}_{2}\)SO\({}_{4}\) (ESS electrolyte carrier solution) and their impact on the environment, using Lenna minor as a bioindicator. It was found that of the dyes tested, both the untreated (AM in ESS+OM) and electro-oxidised versions with an iron anode and a copper cathode [AMFe/Cuox in ESS+OM (OECD medium, a recommended growth inhibition test medium for _Lenna sp._)] exhibited the greatest phytotoxicity to _L. minor_. In contrast, no phytotoxic effects were observed in the treated plant solutions after electro-oxidation with a graphite anode and cathode (AMCox in ESS+OM). The accurate identification of the removed acid mixture was achieved via additional instrumental analyses using ultra-performance liquid chromatography-tandem mass spectrometry and ultraviolet spectroscopy. After electrochemical and biological treatment, the removal rates of the dye components AV90 and AR357 were over 98% and 99%, respectively. These resultsindicate that the approach could serve as a viable alternative or supplement to conventional wastewater treatment methods. The fourth contribution to this Special Issue, written by [PERSON] et al. (contribution 4), examines the effects of bioelectrochemical treatment methods on nitrogen and phosphorus removal and the influence on the concentration of other nutrients in hydroponic effluents. In the experiment, a bioelectrochemical reactor (BER) was used to treat wastewater from hydroponic tomato cultivation. The study showed that the efficiency of nitrogen removal decreased with increasing current density. In particular, an electrical current density of 0.63 A/m\({}^{2}\) exhibited the lowest nitrate concentration in the wastewater. Nitrogen removal efficiency ranged from 41.6% (at a current density of 0.63 A/m\({}^{2}\)) to 8.9% (at a current density of 5 A/m\({}^{2}\)), with a current density greater than 1.25 A/m\({}^{2}\), resulting in lower overall nitrogen removal efficiency. Conversely, phosphorus removal efficiency increased with higher electrical current density, ranging from 95.1% in the R1 reactor to 99.1% in the R4 reactor. The study also analysed the content of other elements in the wastewater and showed that molybdenum, boron, sulphates, and potassium exceeded the permissible limits for the discharge of hydroponic wastewater into the environment. In addition, the study showed that the bioelectrochemical processes in the GMO led to secondary contamination of the hydroponic wastewater with molybdenum ions. The study by [PERSON] et al. (contribution 5) deals with the importance of irrigation in agriculture. With climate change leading to frequent droughts, water scarcity in rural areas, and an ageing rural population, the need for efficient water management and automatic systems is growing. While existing automatic irrigation systems reduce labour and maintain soil moisture, they often lack automation in setting irrigation thresholds based on specific goals, such as increasing crop productivity and water conservation. To solve this problem, an algorithm was developed that uses a database to automatically determine optimal soil moisture levels in conjunction with an intermittent irrigation system designed to maximise water efficiency. An experiment was then conducted in a protected growing environment to assess the productivity of the plants under this system. The intermittent irrigation process was defined using Hydrus 2D moisture movement models to minimise water loss at the soil surface and facilitate soil moisture penetration at various depths. The experimental field with a tomato plantation was divided into plots with manual and controlled automatic irrigation.