Issue 02/2024 (February)

One of the conditions for proper management of the islanded network supplied by LNG regasification stations is planning deliveries based on consumption forecasts. Based on collected meteorological data and gas consumption from a selected station over a two-year period, the impact of atmospheric factors on natural gas consumption was determined using artificial neural networks. The influence of the month and day (artificial parameter) on gas consumption was identified. A neural network model was developed to achieve the best fits using correlation coefficients.

This work presents the results of the analysis of changes in water demand for two selected water companies in Poland caused by the SARS-CoV-2 virus pandemic (first wave). Literature that’s been published so far has been broadly cited in this work, together with selected evidence collected worldwide. The aim of this article is to evaluate the impact of this type of event on the spatial distribution and variability in water demand using GIS software for two selected samples. The resulting geo-statistical analysis allowed to show areas of greatest variability in water demand using measurements from water meters. In order to achieve this the following research tools developed by ESRI were utilised: ‘Space Time Cube’, ‘Emerging Hot Spot Analysis’ and ‘Local Outlier Analysis’. Indicators of space-time trend were calculated by category using the ArcGIS Pro software. Additionally the knowledge base was expanded with results of a survey conducted in Poland on hundreds of water utilities concerning impacts of the pandemic related changes in how they function, their financial liquidity, threats, and challenges. Interesting conclusions from the obtained results were presented and directions of future research in connection to further development of the situation in the world were considered. Given the lack of possibility to reference events of this type from the past, this analysis should be treated as an introductory research of this issue in Poland.

Hydrodynamic computational methods allow for the verification of hydraulic capacity and overload conditions (surcharge and overflow of rainwater) of sewer networks, which were dimensioned using flow duration methods. This paper presents the results of such calculations for given rainfall, which were conducted for a large and complex stormwater drainage system at Warsaw Chopin Airport, based on the hydrodynamic SWMM model (Storm Water Management Model) in version 5.2. The stages of adapting this model for the studied catchment are described. As a result of numerical simulations, overloads were identified in specific stormwater sewer pipes, along with the occurrence of surcharge of rainwater at nodes (overflows). The most adverse condition of the system was identified when the catchment was loaded with Eulerian Type II model rainfall. The simulations considered the throttling (regulation) of flows in the collector using gate valves, the operation of which simultaneously caused an increase of the water level in the sewer pipes. For the example of the adopted catchment, it was demonstrated that the verification of hydraulic efficiency in sewer systems using a hydrodynamic model is justified. The SWMM program serves as a comprehensive tool that enables conducting such calculations.

The article presents the problem of the intensifying influence of the coagulation process on the corrosive properties of water, based on the example of conducted research on the chemical stability of surface water after coagulation with increasing doses of aluminum sulphate. The results of research, methods used to assess the chemical stability of the analyzed water with the use of various stability indices and the comparison of their indications are discussed.

The paper presents experimental results on the effectiveness of forward osmosis (FO) for the recovery and concentration of cationic surfactants (quaternary ammonium salts) from solutions with a wide range of concentrations (50-1000 mg/L). The membrane process ensured an almost 100% separation of cationic surfactants and an effective concentration of the solution components without a leakage into the receiving solution. It has been shown that FO is a membrane technique that allows achieving the goals of a circular economy through an effective concentration and recovery of the compounds and water from the purified solutions