The aim of this study was to characterise conditions and factors affecting fine sand clogging by septic tank effluent on the basis of physical modelling. The physical model consisted of 12 sand columns dosed with sewage from one household (5 persons), preliminary treated in a septic tank. Hydraulic loadings of the sand filters were equal to 82 mm/d. The mean discharge from sand columns, measured as the effluent volume collected during 10 minutes, decreased significantly over the experiment period from 34 cm³/min in August 2000 to 20 cm³/min in August 2001 at the same temperature of about 20°C. First the columns clogged almost completely after 480 days in December 2001, however six columns had remained unclogged till the end of the experiment (March 2002). The temperature had a significant impact on hydraulic conductivity. A vertical distribution of accumulated mass and biomass was investigated in partly clogged sand. Microscopic survey of the clogging layer showed a presence of live micro-organisms, residuals of dead micro-organisms, particularly pieces of small animal armour and many fibres. These particles accelerated the accumulation of solids in the upper clogging layer. The study indicated that temperature impact on the filter hydraulic conductivity was more significant for biological activity, than for sewage viscosity.

The natural environment is constantly under threat from man-made pollution. More and more pharmaceuticals are recognized as emerging pollutants due to their growing concentration in the environment. One such chemical is ibuprofen which has been detected in processed sewage. The ineffectiveness of water methods treatment currently used raises the need for new remediation techniques, one of such is photodegradation of pollutants. In the present study, zinc(II) and copper(II) phthalocyanines were grafted onto pure anatase TiO₂ nanoparticles (5 and 15 nm) to form photocatalysts for photodecomposition of ibuprofen in water. The nanoparticles were subjected to physicochemical characterization, including: thermogravimetric analysis, X-ray powder diffraction, X-ray photoelectron spectroscopy, Brunauer–Emmett–Teller surface area analysis and particle size measurements. In addition, they were assessed by means of electron spin resonance spectroscopy to evaluate the free radical generation. The materials were also tested for their photocatalytic activity under either UV (365 nm) or visible light (665 nm) irradiation. After 6 h of irradiation, almost complete removal of ibuprofen under UV light was observed, as assessed by liquid chromatography coupled to mass spectrometry. The reaction kinetics calculations revealed that the copper(II) phthalocyanine-containing nanoparticles were acting at a faster rate than those with zinc(II) derivative. The solutions after the photoremediation experiments were subjected to Microtox^® acute toxicity analysis.

Guidelines for the design of infiltration trenches of rectangular cross-sections are compared. Four concepts of infiltration into a native soil from linear soakaways of rectangular cross-sections are discussed. The results of calculations using analytical equations were compared with numerical two-dimensional (2D) simulations using HYDRUS computer code and field measurements. Satisfactory agreement was achieved for Kozeny’s concept of infiltration and the free-surface approach, applied to a trench in a highly saturated sandy loam. Theoretical solutions, neglecting matric potential, suggest that the mean infiltration rate along the wetted perimeter of a rectangular trench varies in the range 1.0 to 1.5 of the value of saturated hydraulic conductivity.

This article presents a small diameter gravity sewerage system in a rural area. In this system, domestic wastewater was preliminarily treated in septic tanks equipped with outlet filters, so the effluent features were similar to those of clear water. Additionally, some outlets were equipped with floating-ball check valves to avoid backflow. One of the pressure mains was used as a gravity collector conveying septic tank effluent in the direction of the pumping station during pump idle time. The operation of the system was simulated using SWMM computer code. The simulation results were validated for data obtained from part of a sewerage system in Kolonia Zolkiew and Rozki village consisting of two pumping stations and 86 serviced households using polyethylene pipes of outer diameter 50–63 mm. The results of the measurement of the outflows from one pumping station are presented. The simulation results showed good agreement with the empirical data, especially after several simulation days. The greatest discrepancy during the start-up period was the consequence of the initial conditions describing the empty pipework. Thanks to storage in the pump sumps, septic tank and pipes, as well as their smart operation, a relatively uniform inflow to the pumping stations was achieved. Simulations in SWMM showed that there is still potential to optimize the sewerage system through more adequate pump selection and pipe diameters.