Browse

1 - 10 of 535 items :

  • Electrical Engineering x
  • Energy Engineering x
Clear All
Modernizing and increasing performance of Building Services

Abstract

The aim of the study was to determine the effectiveness of leachates from municipal landfill co-treatment with the dairy wastewater in an aerobic membrane bioreactor. It was working in MSBR (sequential membrane bioreactor) systems twice daily and was equipped with the immersed membrane module installed inside what enabled its back-washing performance. The system was working. The concentration of activated sludge in the membrane bioreactor was equal to 4.0 g/dm3. However, the sludge load was at the level of 0.06 g COD/(g d.m. · d). The oxygen concentration was at the level of 3.0 g O2/m3. The share of leachate was varied in a range of 5 to 15 % vol. The evaluation of the effectiveness of the treatment process was based on the change of parameters characterizing the crude sewage and treated sewage. All analysis was carried out according to standards. Following parameters were determined: COD, BOD5, TOC and concentrations of phosphate phosphorus, total nitrogen and ammonium nitrogen. Chemical analysis is often not enough to define the degree of wastewater treatment. It was used toxicological research to determine the effect on the environment. Toxicity of wastewaters was measured using biotests with Vibrio fischeri and Daphnia magna. The results revealed that the volume of leachate in the treated mixture should not exceed 10 % vol. The following conclusion can be drawn from the present research - co-treated wastewater was not toxic. Landfill co-treatment with the dairy wastewater impacts on the effectiveness of biological wastewater treatment. Leachate includes substances which have low susceptibility to biodegradation; on the other hand, dairy wastewaters provide a lot of organic compounds, which can help to treat them.

Abstract

Pretreatment is an essential step in the conversion of lignocellulosic biomass into valuable products. It aims to increase the biomass susceptibility to enzymatic saccharification to generate fermentable monosaccharides. In this study, the efficiency of 2 % potassium hydroxide (KOH) solution used as a pretreating agent for various lignocellulosic feedstocks, such as corn straw, corncob, and poplar wood, was evaluated. The influence of the pretreatment time, which varied from 0.5 to 24 h at 50 °C, on the alteration of biomass composition was investigated, as well as the enzymatic digestibility. Finally, the overall sugar yields were determined. For corncob, the yield on average amounted to 453.9 ±18.9 mg·g−1 raw (untreated) biomass, regardless of the pretreatment time. The overall sugar yield for both the corn straw and poplar wood biomass increased with increased pretreatment time and ranged from 333.0 to 438.4 mg·g−1 raw biomass and from 123.2 to 215.7 mg·g−1 raw biomass, respectively. Based on the results obtained, the most appropriate pretreatment times for all types of biomass were proposed. The results of this study may be useful for the development of lignocellulosic biomass processing technology.

Abstract

In the present study, the creeks and lakes located at the western shore of Admiralty Bay were analysed. The impact of various sources of water supply was considered, based on the parameters of temperature, pH and specific electrolytic conductivity (SEC 25). All measurements were conducted during a field campaign in January–February 2017. A multivariate dataset was also created and a biplot of SEC 25 and pH of the investigated waters was performed. The average temperatures of the investigated waters were 0.10-8.10 °C. The pH values indicate that most of the water environments of the analysed area are slightly acidic to alkaline (5.26–8.50) with two exceptions: Siodlo II Creek (9.26) and Petrified Forest Creek (8.95), which are characterised by greater alkalinity. At the measurement points closest to the Baranowski Glacier and Ecology Glacier, SEC 25 values were the lowest (26.8–61.1 µS·cm–1), while the remaining values ranged from 79.0 to 382 µS·cm–1 for the whole studied area. Based on the results it is concluded that the periodic intensive inflow of ablation waters, combined with morphological changes in the glacier front, causes a significant variability in the outflow network, creating the conditions for changes in basic physicochemical parameters. Moreover, it is observed that local depressions in the terrain form sedimentation traps in which, alongside fine-grained deposits, compounds can accumulate that originate from in situ sedimentation and that are also associated with surface runoff from the melting of snow cover, buried ice and permafrost.

Abstract

Using survey, we discuss how climate and environmental issues awareness affects residents’ low carbon use behaviour. The results are following. Firstly, climate and environmental issues awareness positively affects residents’ low carbon use. Secondly, perceived effectiveness has mediate effect on the relationship between climate and environmental issues awareness and low carbon use behaviour partly. Thirdly, perceived value has negative moderate effect on the relationship between climate and environmental issues awareness and low carbon use conduct. The results of this study show that when residents feel higher perceived value about their low carbon consumption, they will engage in low carbon use even with lower climate and environmental issues awareness. It tells us that we should treat the residents differently with classification when advocate low carbon use. Specifically, there are some product and service in which consumers can gain high perceived value if the residents frugally use them with high efficiency. And we need to make effort to the following things: we improve the perceived value with hard working, and on the other hand, we make enough effort to enable the residents to deeply experience the perceived value via multiple means.

Abstract

The possibility of applying a colloidal solution of nanosilver in the closed circuit of pool water treatment as a complementary disinfectant with chlorine compounds was presented. The applied nanosilver solution is characterized, by hygienic certificate, as having a very high biocidal effect. Samples of pool water for the control were taken from 5 points of a pool circuit. The safety of the water was appraised by comparing the bacteriological and physicochemical test results with the admissible values specified by hygienic requirements. The results show that nanosilver solution can be successfully applied for precoating the filter bed and supporting the disinfection system. Special attention was paid to the bacteriological purity and stability of the disinfectant concentration. The influence of concentration of colloidal nanosilver (0-25 mg/dm3) on bacterial bioluminescence, crustacean mortality and macroscopic effect of root growth and seed germination of selected plants was analysed. The results obtained were related to the current knowledge on the impact of nanoparticles on indicator organisms. It was found that due to many still unknown mechanisms of interaction and transformation of nanoparticles in living organisms, further study of this issue is necessary.

Abstract

To increase the dewatering effect, sewage sludge should be properly prepared before dewatering. Sludge conditioning is a process whereby sludge solids are treated with chemicals or various other means to improve dewatering characteristics of the sludge by reducing the specific resistance and compressibility of the sludge. The aim of the research was to determine the possibility of increasing the efficiency of sewage sludge dewatering by applying chemical agents and ultrasonic field. Some parameters, such as suspension, chemical oxygen demand (COD), phosphorus and ammonium nitrogen content in sludge supernatant, were also analysed. Digested sludge belonged to the group of hardly dewatered sludge, its capillary suction time (CST) was of high value (2639 s). The lowest CST value (88.5 s) was obtained for the unsonicated sludge prepared only with PIX 113 at a dose of 7.0 mg/g d.m. Both the dose and the type of chemicals used, as well as the time of sonication, had an impact on the changes occurring in sludge properties. The increase in mechanical dewatering efficiency was obtained by using a combination of methods applied for sludge preparation, where the sonication of sludge was used at the preliminary stage and followed by dosing chemical substances. This resulted in the reduction of sludge final hydration and changes of other parameters. In addition, combined action of PIX 113 and Zetag 8180 allowed to reduce the content of suspended solids and COD in sludge supernatant.

Abstract

The structure of phytoplankton assemblages in three small water bodies was compared and abiotic factors were described. It indicated considerable differences in the species abundance and biomass of the phytoplankton as well as the chemical composition of water between artificial pond (No. 2) and others. A total of 455 phytoplankton taxa were recorded. All ponds were characterized by greatest species richness of Chlorophyta. The highest biomass was noted in August-September 2015, and it was true for each pond. The CCA models showed dependences between the variables under study and phytoplankton groups. They indicated which environmental variables had the greatest influence on the biomass of phytoplankton in the waterbodies under analysis. The biomass of most of the taxonomic group in the phytoplankton (except Miozoa) depended on the presence of nitrogen not only in form of nitrates but also in the form of mineral nitrogen. The research findings suggest the trend of future studies on the phytoplankton in these ponds. The analysis of its variability should also include the influence of light and the influence of consumers on the food chain in the ecosystem.

Abstract

Lead is a heavy metal with strong toxic properties. This chemical element is found in wastewater and sometimes in drinking water. The article deals with the removal of lead(II) ions from polluted water using a sorption process to determine the most effective sorbent for the removal of lead(II) ions. Three sorbents were used in the research: clay, sapropel, and iron sludge. All three sorbents investigated reduce the concentration of lead(II) ions in water: clay efficiency was of 65.7–90 %, sapropel of 94.3–100 %, and iron sludge of 84.3–97 %, depending on sorbent type and contact duration. The research has shown that the most effective way to remove lead(II) ions from the test water is sapropel. Using different amounts of sapropel (1, 2, 3, 4, 5, 6 g/dm3 and 0.1, 0.2, 0.4, 0.5, 0.6, 0.8 g/dm3) and different duration of contact (30, 60, 90, 120 and 150 minutes), the concentration of lead(II) ions in the test water after purification did not exceed the permissible values for drinking water (10 μg/dm3), so that the lowest sapropel content of 0.1 g/dm3 can be used for sorption. Lead(II) ions are most effectively removed when contact time is 30 min.

Abstract

The presented article relates to aspects of PV module testing using natural sunlight in outdoor conditions. It is a continuation of the article Part III: parameters of atmospheric transparency - determining and correlations. This article discusses the practical application of the indexes: atmosphere purity - k Tm, diffused component content - k s/o, beam clear sky index - K b - in testing various modules in outdoor conditions. Their influence on the conversion of modules made from various absorbers and various technologies is demonstrated. Their practical application in module testing in outdoor conditions is described and it - has been demonstrated that the results of the analyses carried out using the indexes conform to the results obtained using spectral parameters of solar radiation (i.e. APE and UF). These are the measurements that require the use of very expensive equipment.