Filters
Hydraulic Calculations of a Slotted Separator Using the SSIIM Program
Analysis of the results of the hydraulic calculations of a slotted separator, allowed for changes in the separator design taking into account the reduction of flow turbulence, ensuring the continuity of water flow and sediments as well as optimal location of the slots. The separator is an important element of the installation for hydromechanical removal of sediments from the bottom of a water reservoir. Tests were carried out on the physical and mathematical model. Hydraulic calculations and numerical simulations were carried out using the SSIIM (Simulation of sediment movements in water intakes with multiblock option) program. The program enables three-dimensional analysis of flows and transport of sediments in rivers and canals by solving the Navier-Stokes equation and the turbulent model k-. A number of numerical experiments of the separator work were carried out for various design solutions regarding the geometry of the inlet and outlet channels and their connection with the chambers as well as slots system. The numerical simulations and conducted research on a physical model, allowed to develop an optimal solution.
The impact of grey water on yield and aesthetic properties of perennial ryegrass
Selecting optimal turf varieties is crucial for the sustainable management of urban green areas. This study focused on enhancing the overall quality and resilience of urban, suburban, and peri-urban areas. It aimed to assess the aesthetic acceptability of perennial ryegrass turf irrigated with greywater. Sand pots containing perennial ryegrass were irrigated with semi-natural greywater and tap water at two irrigation levels of 15 and 30 mm∙week−1 to examine their effects on aesthetic properties. The experiment included two variations: with and without fertilisation. The study objectives were evaluated using a visual aesthetic scale and by measuring the total dry and wet mass yield of ryegrass. While the aesthetic properties of the grass were found to be relatively low, they were deemed acceptable. The presence of fertilisation had significant impacts on both aesthetic properties and biomass yield. The experiment demonstrated that perennial ryegrass can be cultivated effectively at relatively low irrigation levels, even in soil lacking an organic fraction. The results indicate the possibility of maintaining this type of vegetation in the form of green roofs and vegetative swells. In the case of sandy soil lawns, their purpose should not include intensive trampling due to relatively poor rooting and low soil stability. These findings underscore the potential for sustainable landscaping practices that incorporate greywater irrigation and highlight the importance of considering various factors to optimise aesthetic appeal and productivity of green spaces.
The Influence of Fibers from Domestic Laundry Wastewater on the Clogging Process of a Filter
This study presents the impact of the size and shape of particles in laundry wastewater on the clogging process of a porous material. Clogging can be defined as a mechanical limitation of flow through porous media. The process of mechanical clogging was investigated in this study. The research was conducted in laboratory conditions in a filter column filled with glass beads whose diameter corresponded to coarse sand. The results reveal the influence of graywater quality on filter hydraulic conductivity and bed clogging, showing the impact of fiber particles in wastewater (sewage from home laundry) on the clogging process in soil. The results confirm that fiber particles significantly reduce filter permeability, particularly due to the formation of a filter cake. As analyzed in this paper, the distribution of quantitative data on particles of different sizes found in laundry wastewater indicates that they mainly accumulate in the upper layer, where particles with fiber lengths ranging from 0 to 1600 µm can be found. The average length of the fibers decreased with increasing depth. At a depth of approximately 10 cm, fibers with dimensions in the range of 0 to 100 μm were predominantly observed.
Application of Physical and Numerical Modeling for Determination of Waterway Safety under the Bridge in Kaunas City, Lithuania
The main problem presented in this paper is the safety inlet navigation of the waterway below the bridge in the city of Kaunas in Lithuania. The analyzed reach is located in the Nemunas river downstream of the Kaunas dam. It is a part of the waterway E–41 leading to the Klaipeda harbor on the southern coast of the Baltic Sea. The work was initiated by the Lithuanian company UAB “Inžinerinis projektavimas” with funds from the project called European Union Trans-European Transport Network (EU TEN-T). The main requirement imposed along this reach is to keep sufficient depth even in the range of the lowest flows. The depth is sufficient if it is not lower than 1.15 m for minimum flows such as Q95% and Q95% with ice. The hydraulic conditions for maximum flow Q50%, Q5%, and Q1% are also taken into account for control because the threat of hydraulic jump generation was also noticed. The research is based on georeferenced data from public and non-public sources. The hydrologic data were received from the Lithuanian Hydrometeorological Service. The physical model was created in the Water Laboratory of the Department of Hydraulic and Sanitary Engineering at Poznan University of Life Sciences, Poland. The preprocessing of spatial data in ArcGIS 10.8.2 and rules of hydraulic similarity were implemented in the process of physical model preparation. Three experiments were conducted in the laboratory with scaled values of Q95%, Q5%, and Q1%. The measurements of the water surface and evaluations of the average velocity were used to validate the 2D numerical model prepared in HEC-RAS 6.3.1. The basic layers of the HEC-RAS model were preprocessed in ArcGIS 10.8.2 by ESRI company. The numerical model was implemented to test different values of unknown roughness of the channel bottom. The simulations were conducted for the real values of Q95% and Q95% with ice and Q50%. The results of the simulations were depth and Froude number maps. These maps were classified into zones of no risk, middle risk, and high risk. ArcGIS in the post-processing phase was applied to identify the locations of the hazards. The magnitude of risk was expressed in terms of minimum depth achieved, maximum Froude number, as well as the length of the reaches with high risk related to these two factors. The threat of hydraulic jump formation below the bridge was also noticed. Conducted results confirmed that the combination of hydrodynamic simulations and geoprocessing in the pre- and post-processing stages could be a powerful tool in hydraulic engineering analyses. Additionally, it is worth noting that numerical modeling enables a wider analysis of potential conditions than could be possible with a physical model only.