Mathematical models of activated sludge process are well recognised and widely implemented by researchers since 1980's. There is also numerous software available for modelling and simulation of activated sludge plants, but practical application of those tools is rather limited. One of the main reasons for such a situation is a difficult process of model calibration the requires extended data sets collected at investigated plant. Those data are usually not included in a standard plant monitoring plan. In the paper the problem of model calibration with the data sets derived from standard monitoring plan is discussed with a special regard to simulation objectives and data availability. The research was conducted with operational data from Białystok Wastewater Treatment Plant. The model of the plant was based on Activated Sludge Model No.3 developed by IWA Task Group and implemented in ASIM simulator. Calibration and validation of the model gave promising results, but further applications should be carefully considered, mainly due to uncertainties underlying input data.

Water and energy are the main natural resources, and their rational use is the basis for sustainable development. Therefore, the energy efficiency of water supply networks is one of the priorities for the management system of water utilities. Many methods and indicators can be used to assess the energy efficiency of water distribution networks (WDNs), and their choice should be adapted to the characteristics of a WDN. This paper presents an energy audit of WDNs that are supplied from five reservoirs located above the supply area, to which water is supplied from four underground and surface water intakes. In the analysis of the system operation, a hydrodynamic computer model of the water distribution network was used to estimate the operating parameters that are necessary to determine the energy efficiency indicators. A new method for calibrating the emitter coefficient used for water loss modeling is also proposed. The conducted audit showed that more than 70% of the energy supplied to the WDS was “lost”, mainly due to friction (37%) and water losses (27%). Thanks to hydraulic modeling, it was possible to indicate that 34% of the energy lost in the system was related to the use of pressure-reducing valves (PRV), and that only 3% was directly related to friction. In turn, the majority of leaks are attributed to service connections (17.4% vs. 8.8% in the water distribution network).

The purpose of the study was to present the principles of creating and implementing an integrated water and wastewater management system based on hydrodynamic modeling of water distribution and sewage disposal systems in small and medium-sized municipal enterprises. The computer modeling of water and sewerage networks is an efficient tool for finding the causes of increased costs of operation of these plants. The simulations carried out in modeling programs enable to quickly find the optimal variant to solve the problem of exploitation or economically effective direction of their modernization. Geospatial data (GIS) is being increasingly often being used to optimally manage the municipial water and sewage infrastructure. This gives an additional analytical tool for planning, designing, obtaining operational data, etc. The integration of hydraulic models of the water supply and living and economic networks into one coherent management system is possible, owing to which, a holistic assessment of the functioning of the water and sewage management system in the city is possible. The decision support systems based on the spatial information system (GIS) associated with various specialized software, are becoming the standard of modern management of a water and sewage company. To date, only about 40% of enterprises in this industry in Poland have used systems of this type. In addition, most of the GIS-based management systems used in practice are limited to an inventory of existing network resources and integration of many databases in one coherent IT system. Only in a few cases, the systems of this type contain modules modeling the network operation under dynamic conditions, which results primarily from the additional implementation costs related to the construction of sufficiently reliable models of the water supply and / or sewerage network. Implementation of the proposed solution includes: construction of a water supply network simulation system, construction of a domestic and economic sewage system simulation system, devising scenarios for system operation under the conditions of city development and climate change, multi-criteria assessment of the economic effectiveness of systems operation taking into account social and environmental criteria, development of an integrated management system the system, taking into account the guidelines for increasing the effectiveness of its operation and work safety.Keywords: computer modeling of water supply and sewerage networks, GIS

The age of water in the municipal water supply system is one of the main factors influencing water quality. To create a good quality hydraulic model, one must achieve a high level of calibration accuracy with real life measurement data. Before we start building our model, we must decide on the model’s level of detail, that is, its complexity. We must know if skeletonization of the network graph and different hydraulic timesteps have an influence on simulation results. This study strives to prove that this decision can lead to unforeseen problems during the calibration process, thus making it impossible to achieve the required calibration precision. In order to prove this, two different model variants were created with different levels of graph detail, and simulation data results were used to determine which model variant is best suited to achieve the highest fidelity simulation results. Following this, the chosen model was run with different hydraulic timestep settings, which made it possible to showcase the large influence this setting has on achieved results.

Monitoring and computer modeling of water networks is an effective tool supporting water management in the city. The aim of this paper is to present the results of measurement campaigns carried out in Polanica-Zdrój, preceding the construction, calibration and validation of the hydrodynamic model of the water supply network. The obtained results showed that the changed conditions of the functioning of the local community during a pandemic also significantly affect the way water is used. Daily distribution of water consumption by residents of multi-family housing has been significantly “flattened” due to remote work and extended time at home. This confirms the necessity to conduct on-line measurements in order to calibrate the model reliably and effectively use the results of computer simulations.