The sewerage network in Poland, built in the early 20th century, has been losing its original water-tightness and flow capacity. To bring these characteristics back, rehabilitation works are performed. The initial capacity of sewers can be restored without affecting the urban environment thanks to the trenchless technology. The sewer subjected to rehabilitation receives a new internal leakproof layer capable of preventing groundwater infiltration as well as sewage leaks, which can contaminate the environment. This paper intends to compare the trenchless technology with traditional open cut trench excavation. In the study, two variants of trenchless rehabilitation were considered: one performed with the help of GRP panels and the other using cured-in-place pipe (CIPP) lining. Flow velocities and flow rates in the sewers before and after rehabilitation were compared. Also, selected economic and environmental aspects of sewer rehabilitation methods were examined.
Soumya Chatterjee, Sibnarayan Datta, Sonika Sharma, Sarika Tiwari and Dharmendra K. Gupta
Life on Earth harbours an unimaginable diversity of microbial communities. Among these, gut microbiome, the ecological communities of commensal, symbionts (bacteria and bacteriophages) are a unique assemblage of microbes. This microbial population of animal gut helps in performing organism’s physiological processes to stay healthy and fit. The role of these microbial communities is immense. They continually maintain interrelation with the intestinal mucosa in a subtle equilibrium and help the gut for different functions ranging from metabolism to immunologic functions like upgradation of nutrient-poor diets, aid in digestion of recalcitrant food components, protection from pathogens, contribute to inter- and intra-specific communication, affecting the efficiency as disease vectors etc. The microbial diversity in the gut depends upon environmental competition between microbes, their sieving effects and subsequent elimination. Due to wide diversity of anatomy and physiology of the digestive tracts and food habits, the gut microbiome also differs broadly among animals. Stochastic factors through the history of colonization of the microbiome in a species and in situ evolution are likely to establish interspecies diversity. Moreover, the microbes offer enormous opportunity to discover novel species for therapeutic and/or biotechnological applications. In this manuscript, we review the available knowledge on gut microbiome, emphasising their role in health and health related applications in human.
Krzysztof Gondek, Agnieszka Baran, Monika Mierzwa-Hersztek and Michał Kopeć
The aim of the research was to evaluate the effect of temperature during the treatment process as well as the effect of adding plant materials to sewage sludge on selected chemical properties and Vibrio fischeri response. The mixtures were placed in a chamber furnace, under airless conditions. Two temperature procedures were applied: 300 and 600ºC; the exposure time in both cases was 15 minutes. Thermal treatment of sewage sludge without a plant component is not well-founded and may cause an increase in concentration of trace elements. Using the temperature of 300ºC caused significantly lower changes in the contents of total forms of trace elements than using the temperature of 600ºC. The metals extracted from the studied mixtures were not toxic for the Vibrio fischeri. In the case of the fractional composition of humic compounds, thermal treatment of mixtures of sewage sludge and plant materials is not beneficial in terms of labile fractions, but it had a beneficial effect on stabilizing the durable bonds between C compounds in those mixtures.
Asim Yaqub, Mohamed Hasnain Isa, Huma Ajab, Shamsul Rahman Kutty and Ezerie H. Ezechi
Produced water is actually the wastewater separated from petroleum crude oil. Electrochemical-oxidation experiments was conducted for degradation of 16 priority polycyclic aromatic hydrocarbons (PAHs) using DSA type Ti/IrO2 anode. Laboratory scale batch reactor was used for degradation studies. To get the maximum PAHs removal electrochemical process optimized on three independent variable current density, pH and electrolysis time. The response surface modelling (RSM) based on a Box-Behnken design was applied to get appropriate experimental design. X1, X2 and X3 are the coded factors of independent variables such as the current density, pH and electrolysis time, respectively. Maximum removal was 95.29% at optimized conditions such as current density of 9 mA/cm2, pH 3 and electrolysis time 3.7 h. Quadratic model was suggested best fit model. The results of the Analysis of Variances (ANOVA) for PAHs demonstrated that the model was highly significant.
Edyta Kudlek, Daniele Silvestri, Stanisław Wacławek, Vinod V.T. Padil, Martin Stuchlík, Lukáš Voleský, Pavel Kejzlar and Miroslav Černík
Recently electrospinning has gained significant attention due to unique possibilities to produce novel natural nanofibers and fabrics with controllable pore structure. The present study focuses on the fabrication of electrospun fibres based on gum karaya (GK), a natural tree gum, with polyvinyl alcohol (PVA), and functionalization of the membrane with TiO2 nanoparticles with further methane plasma treatment. The GK/PVA/TiO2 membrane was analyzed with several techniques including: fourier-transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX), and water contact angle, in order to characterize its morphological and physicochemical properties. The GK/PVA/TiO2 membrane was further successfully used for the degradation (under UV irradiation) of bisphenol A and diclofenac from aqueous solution. It was also observed that the degradation kinetics of these compounds are faster in comparison to the UV treatment alone.
Katarzyna Pawęska, Aleksandra Bawiec and Krzysztof Pulikowski
Treatment of wastewater produced in Service Areas (SA) located on expressways and highways is a worldwide problem because of increasing amount of roads and specific composition of those kinds of sewage. Insufficient removal of pollutants from wastewater discharged into surface water may cause serious environmental problems. In the present study efficiency of treatment of wastewater with high ammonium concentration in biological membrane system used on SA was investigated. Concentrations of ammonia nitrogen in wastewater flowing into bioreactor in none of the tested objects did not fall below 99.0 mg of N-NH4·dm−3. Because of high ammonium content in sewage and high pH reaching value about 9, it is almost impossible to create favorable conditions for microorganisms that run purification processes resulting in low efficiency of phosphorus and nitrogen removal (reduction of biogenic compounds did not exceed 15%). Treatment of wastewater consisting mainly of urine with commonly used biological membrane technology has to be widely tested to perform suitable quality of discharged wastewater, to provide safety of surface water environment.
Dorota Brzezińska, Marek Dziubiński and Adam S. Markowski
Despite the fact that LPG (Liquefied Petroleum Gas) is used in a large number of cars, tests have not yet been carried out to ascertain how hazardous can be the release of LPG from the car when parked in enclosed garages. The problem applies to both public and industrial parking areas, especially in Poland, where more than 10% cars are fueled by LPG. The paper describes full scale experiments, which demonstrate conditions that may occur in a garage in the event of accidental LPG release from the car installation. Over the course of the tests, a series of six LPG spillage tests were performed to study emission time and flammable cloud formation depending on the accidental gap diameter. Additionally, to enable the visual observation of the gas dispersion and influence of the ventilation system the experiment was conducted using well visible CO2 gas cloud, produced from dry ice. The experiments have shown that without ventilation LPG can accumulate on the floor of the enclosed garage for a long time, which generates a high explosive hazard. However, good ventilation (especially jet fan systems) can quickly remove hazardous flammable LPG clouds. Moreover, very important for effective LPG detection is the location of detectors closer to the floor than is currently recommended - at a height of 30 cm.
The method based on rough set theory (RST) was used in the study to establish the rate of mass accumulation of waste in households in rural areas, which are characterised by different economic types, in case of which traditional statistical analyses are usually hardy reliable. The following indicators available in the General Statistical Office’s statistics were used in the analysis: population density, income level, main source of income, economic type of the municipality, area of agricultural land, age of the buildings and participation of gaseous fuels in meeting heat demands. The method shown should not be considered as a competition for statistical methods, but it could complement them, especially in cases when there are few objects to analyse, the more so as it proves useful in cases where input data are general, imprecise and uncertain. As has been shown in the study, with such data and a small number of objects, the relative error of estimation was 13% on average.
The CO2 absorption process using aqueous amine solutions has been the most promising technique used for the removal of CO2 from gas streams in energy sector. In recent years, many researchers tested solutions which are composed of several compounds: a slow reacting tertiary amine- and a fast amine acting as an activator. In this paper, the CO2 absorption rate in an aqueous solution of N,N-diethylethanoloamine (DEEA) and activated solutions DEEA is investigated experimentally. The activators considered are sterically hindered amines: 2-amino-2-methyl-1-propanol (AMP), 2-amino-2-methyl-1,3-propanediol (AMPD) and N-methyl-1,3-propanediamine (MAPA) from the group of polyamines. The experiments were conducted over the temperature range of 303-333 K and the total amine concentration of 2 M. From the CO2 absorption experiments into mixed aqueous solutions of DEEA and MAPA, it was found that the addition of small amounts of MAPA into aqueous DEEA solutions has a significant effect on the enhancement of the CO2 absorption rate. The application of hindered amines: AMP or AMP as activators resulted in a marginally improvement of the absorption rate of CO2.
Energy willow as a species with broad adaptation possibilities, large production capacity and a wide range of applications, takes a special place among the plants grown for energy production. In this work an analysis was conducted in respect of the usefulness of this type of wood from experimental plantations as a clean source of energy generated in the combustion process. The heat of combustion and net calorific value of dry matter of energy willow wood, including selected sorts and classes of thickness were determined. Energy willow has a natural ability to accumulate heavy metals which are oxidized during the combustion process or remain in the ash, and consequently repollute the environment. In order to determine the environmental impact the content of heavy metals was examined in energy willow wood and in the soil of the experimental plantation. Metal concentrations were determined by the Atomic Absorption Spectrometry method (AAS). Results of the tests confirmed a close relationship between the heat of combustion, calorific value and wood thickness as well as its location in the tree structure. Furthermore, very large differences were found in the content of heavy metals in the samples of both willow wood and soil. The levels of heavy metal content in the wood of energy willow determine the agricultural use of ashes produced during combustion.