Assessment of leakage management in small water supplies using performance indicators.

The revision of the Drinking Water Directive (DWD), which the process of consultation by the European Parliament is coming to the end, includes a commitment for all Member States to assess the level of water leakage. The overarching aim of this action is to reduce water loss through leaks. In regard to this, use of performance indicators as suitable to enable assessment of water utility performance with regard to leakage reduction, including impacts on environment and cost-efficiency, is recommended. The paper provides results from water losses evaluation with the set of performance indicators (PI), considering dependence on the availability of resources and specific operating conditions. An analysis of different PI that are necessary to evaluate in most of leakage reduction methods was conducted considering step-by-step approach. Furthermore, the most relevant data for leakage analysis and management on a network level was determined. Presented PI can be used to improve leakage management of small water supply system. Similarly as in the Deming cycle, the described tool provides for planning activities, executing activities in accordance with the plan, checking the degree of execution of objectives included in the plan, and on the basis of conducted analyses and lessons learned, the so-called improvement. The results of the analysis lead to the conclusion that through a comprehensive, systematically improved strategy, the high effectiveness of the system could be reach. The reliable monitoring does not have to be based on advanced technological methods, which are often unavailable for small water supply system, due to high investment and operating costs. The results indicate that integrated IT systems, as SCADA, might not be directly beneficial to water loss management in small networks with moderate leakage levels.

Sustainable management of biological solids in small treatment plants: overview of strategies and reuse options for a solar drying facility in Poland.

The issue of sustainable management of biosolids (excess sludge) from wastewater treatment is an important issue in the entire developed world. Residual sludge disposal costs and environmental impact may be significant, and reducing such costs, as well as the energy consumption for dewatering and drying, is a key issue for safe and sustainable sludge disposal, considering the recent ban of some disposal options, such as landfilling, in many European countries. An alternative to thermal technologies is solar drying (not to be confused with bio-drying, very close to the concept of composting). Solar greenhouse drying technology is characterized by reduced land requirements compared with traditional outdoor drying beds, as well as by low-energy requirements compared with other thermal drying methods. Process operation is cost-efficient, with close to no maintenance, and observed specific evaporation rates up to threefold higher than conventional drying beds. Many applications of this technology exist in Poland, Germany and Austria: more than 10,000 t of wet sludge per year is treated in this way in Germany alone and almost as many (9000 t/year) in Poland. This paper examines current biosolids treatment technologies applicable to small wastewater treatment plants (2000-9999 population equivalents served) and opportunities for possible solids reuse in Poland in view of sustainable circular economy schemes. In particular, a purely solar-driven greenhouse facility for sewage sludge drying was investigated under different conditions (season, temperature, environmental humidity) and possible improvements for its efficiency evaluated. Sludge processed by solar drying could have different final disposal pathways, according to season, in accordance with the prescriptions of the new National Waste Management Plan of Poland.

Cost-effective removal of COD in the pre-treatment of wastewater from the paper industry.

The present paper reveals results of research for cost-effective removal of chemical oxygen demand (COD) contained in industrial paper mill effluent. Not only process efficiency but also wastewater treatment costs are discussed. Different pre-treatment processes are applied aiming to investigate the COD removal before discharge to the municipal sewage network. The objective of this paper is to find the optimal operating conditions for the coagulation process. The effects of key operational parameters, including the type of coagulant, initial pH, temperature and coagulant dose, on COD percentage removal were investigated. The laboratory experiments confirmed the high efficiency of chemically enhanced mechanical treatment towards COD. The data obtained show that even low dose of chemicals provides sufficient COD reduction. The initial pH of the wastewater had a significant impact on the COD removal. Under the optimal operational conditions (pH = 7.5, T = 18 °C) the treatment of wastewater from paper industries by coagulation has led to a reduction of 70% COD for wastewater discharged. In terms of the investigated paper industry wastewater, polyaluminium chloride appears to be most suitable for treatment of high COD concentration. However, in an economic evaluation of requirements for wastewater treatment, operating costs and associated saving were such that PAX was more favourable.

Water quality and resource management in the dairy industry.

Food industry is one of the most important and fastest growing sectors of economy in Poland. This sector is also characterized by high demand for the resources, particularly for water. Polish food industrial plants consumed 793 hm3 of water in 2014. Dairy branch had a combined 35% share of the above consumption. As shown by the data obtained from the Polish Central Statistical Office, the majority of dairy plants use its own source of water, so this branch is also important water producer in Poland. Water used for dairy industry should meet the requirements of at least drinking water quality, so the factories need to treat the water. This paper analyses the correlations between selected technical process, equipment profiles and water quality, and consumption in two types of dairy factories (DF). The first one DF-1 processes approx. 50,000 L of milk, and the second, DF-2 processes approx. 330,000 L of milk per day. The water taken from the wells needs to be pre-treated because of iron and manganese concentration and due to specific requirements in various industrial processes. As a result of this work, we have managed to propose technological solutions in the context of water consumption rationalization. The proposed solutions aim at improving water and wastewater management by reducing the amount of consumed water by industry.

Health risk as a consequence of exposure to trihalomethanes in swimming pool water

The article presents the formation and toxicity of trihalomethanes (THMs), substances belonging to Disinfection ByProducts (DBP), formed as a result of pool water chlorination. Concentration of THMs in pool water has been standardised in Poland since recently. THMs concentration in pool water depends on multiple factors, mostly the method of water disinfection, including chlorine or organic substance (TOC) concentration. Apart from that, the level of exposure of swimmers to the toxic effect of THMs is affected by their content in the air of swimming pool halls, intensity of swimming as well as time of stay in the indoor swimming pool area. The water and air temperature as well as number of swimmers and time of their staying in pool have also significance influence on THMs concentration. In order to decrease the quantity of THMs in pool water, alternative disinfection agents are applied. Additionally, an efficiently operating pool ventilation system as well as proper water treatment method are also important. Because THMs are produced from organic material under the influence of the chlorination, the users can have an impact on decrease of the THMs concentration in pool water, for instance by taking a shower prior to entering the pool or by wearing a swim cap. The results of studies conducted in 2015 showed that the quantity of THMs in pool water depends on type of the pool (indoor, outdoor), water replacement frequency, water treatment system, chlorine dose and TOC content. In most collected samples, the THMs concentration exceeded the admissible norm (100 µg/L).