Conventional wastewater treatment methods include various physical, chemical and biological processes. The results of such treatment can be limited because of high investment cost or, in some cases, due to poor treatment efficiency. For that reason, new approaches are continuously being developed as a means of supplementing or replacing traditional water treatment methods. The paper provides an overview of development of nanotechnology over time in the sphere of wastewater treatment, and examines the influence of nanomaterials on human health and environment, while also providing a review of future development trends in nanotechnology.

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Water conditioning is a method of removing altering minerals, chemicals and contaminants from a water source and it is carried out on facilities equipped with the corresponding electro-mechanical equipment. Although efficient, conventional processes typically use several complex devices connected to a single functional unit, which are often expensive to maintain and occupy large areas. Therefore, the aim of this paper is to present the electrocoagulation (EC) method as an alternative to conventional water conditioning processes. The examples of previous studies of the EC process application is presented in this paper. The focus of the paper is to investigate the influence of the certain operational parameters such as pH, temperature, electrode material, etc., on the efficiency of pollutant removal such as Escherichia coli and elevated concentrations of iron, arsenic, manganese, ammonia and others. Further, an economic analysis is made, which, from an economic point of view, shows when it is feasible to use the EC in the conditioning process. Furthermore, a case study of electrocoagulation process for Total Nitrogen (TN) removal is presented. According to results, 69.7 % of TN was removed with aluminum electrodes after 240 minutes. For this case, total operating costs were 7.60 €/m3.

In water supply systems, pressure management in most cases is proven to be the most cost-effective activity related to water loss control. As an advanced method of pressure control, it is possible to use variable frequency drives for centrifugal pump control. Pressure regulation can be performed with constant pressure or with proportional pressure control. The application of proportional pressure control is particularly applicable in water supply systems as the operating pump performance is constantly adapting the pressure to the actual demand. Along with lower leakage losses, it also results in lower energy consumption and the elimination of non-stationary phenomena, thereby extending the pump lifetime. Therefore, the paper presents a theoretical discussion of the proportional pressure control. Possible savings are shown on the numerical example of water supply system of the city of Velika Gorica.

Nowadays, the values of natural fresh-water resources are increasing and a Pan-European methodology for water quality assessment was applied in the case of the Skadar Lake eco-system. The main goal of this paper was to classify Skadar Lake according to the environmental quality standards, prescribed in the EC directives and EUROWATERNET requirements. Basically, the criteria enable to classify the water as belonging to one of, usually, five classes with respect to a number of physicochemical and biological parameters. To determine the reference state, that could be expected if they were not significantly affected by human activities, was the second most important task. Some modeling was done to support interpretation of the measured data taken seasonally from May to October in the 2002-2004 period. A clear picture of the current state of the Skadar Lake was created and the classification will facilitate the interpretation of the environmental data relating to the Skadar Lake ecosystem. As a general conclusion it could be stated that the lake ecosystem is still in good conditions, although a small care has been done to it in the past