The main goal of the present study was to examine the operating characteristics and mechanisms of membrane fouling in integrated membrane bioreactors (IMBRs) at diff erent temperatures. Two IMBRs, each with identical dimensions and confi gurations, were used in the study using synthetic domestic sewage at a low temperature (10°C) and high temperature (25°C). The results indicated that the removal effi ciency of chemical oxygen demand reached 93–96%, but the membrane contribution rate of IMBR2 (10°C) was higher than that of IMBR1 (25°C). The separation burden of the membrane on organic compounds increased at low temperature, which may have sped up the rate of membrane biofouling. The absolute rate of trans-membrane pressure build-up was faster at low temperature, leading to shorter IMBR operating times. Soluble microbial products (SMPs) and extracellular polymeric substances (EPSs) in the IMBRs signifi cantly increased at low temperature. These substances intensifi ed defl occulation, with an accompanying reduction of fl oc size and the release of EPSs at low temperature, which facilitated the formation of cake foulants on the surface, covering the entire membrane area. The protein and polysaccharide concentrations of SMPs and EPSs in the IMBRs were correlated with the concentration of C8-HSL. It was demonstrated that temperature aff ected the concentration of C8-HSL, which controlled the excretion of EPSs and SMPs and thus the membrane biofouling process.
A representative group of hydrophilic fungi from the genus Trichoderma isolated from lignocellulose composts with varying degrees of maturity was analyzed for their ability to biodegrade a harmful anthraquinone dye, i.e. Remazol Brilliant Blue R (RBBR). In RBBR-containing post-culture liquids, there were determined the degree of RBBR decolorization, horseradish peroxidase-like, superoxide dismutase-like, and xylanase activities, and the concentrations of low-molecular phenolic compounds. The study results demonstrated that Trichoderma asperellum, T. harzianum, and T. lixii strains isolated from compost containing larger amounts of easily available lignocellulose fractions, i.e. grasses, exhibit higher RBBR decolorization effi ciency ranging from 0.3 to 62% than T. citrinoviride strains isolated from compost II, which contained greater quantities of hardly degradable lignocellulose. The decolorization of remazol blue R by the investigated Trichoderma strains intensified signifi cantly with the increase in peroxidase activity and it was correlated with a decline in the content of low-molecular phenolic compounds. The dynamics of changes in the horseradish peroxidase-like, superoxide dismutase, and xylanase activities in the aqueous post-culture liquids of the investigated fungal strains depended largely on the duration of the culture. Given their ability to adapt to water environments, e.g. wastewater, and to decolorize and detoxify the RBBR anthraquinone dye, Trichoderma fungi can be used for bioremediation of such environments.
Bacterial infections that are due to consumption of poor quality water are still an important threat to human health and life. The aim of the article was to investigate the bacteriological threat of water from home wells. The results of water testing from individual wells constituted research material. On their basis, the health risk of fecal streptococci, coliforms and Escherichia coli was assessed and an attempt was made to assess the impact of pollution on the health of residents. The results of water testing in private wells showed unacceptable values for bacteriological pollution. A signifi cant health risk was found for fecal streptococci, coliforms and Escherichia coli. The authors pointed out the need to take extensive actions aimed at raising environmental and health awareness of the inhabitants in terms of water quality used for living purposes, in particular for consumption.
Demonstrating the impact of time-dependent ground adsorption capacity on the change in chemical composition of groundwater is an important issue in understanding the groundwater mass transport process. Commonly used parameters characterizing ground adsorption capacity (Ra, ��xu = ux/Ra, Δ ������ C�� ) were analyzed in this work to demonstrate time-varying values of this capacity for a chosen type of ground. Analysis of values of the selected parameters showed a gradual time decline in ground adsorption capacity as well as a gradual increase of groundwater contamination. This gradual increase in groundwater contamination over time is also important in practice. It implies the necessity to use more and more advanced (expensive) methods of water treatment in groundwater intakes.
The paper presents an application of Life Cycle Assessment (LCA) method for the environmental evaluation of the technologies for the fertilizers production. LCA has been used because it enables the most comprehensive identifi cation, documentation and quantifi cation of the potential impacts on the environment and the evaluation and comparison of all signifi cant environmental aspects. The main objective of the study was to assess and compare two technologies for the production of phosphorus (P) fertilizers coming from primary and secondary sources. In order to calculate the potential environmental impact the IMPACT 2002+ method was used. The fi rst part of the LCA included an inventory of all the materials used and emissions released by the system under investigation. In the following step, the inventory data were analyzed and aggregated in order to calculate one index representing the total environmental burden. In the scenario 1, fertilizers were produced with use of an integrated technology for the phosphorus recovery from sewage sludge ash (SSA) and P fertilizer production. Samples of SSA collected from two Polish mono-incineration plants were evaluated (Scenario 1a and Scenario 1b). In the scenario 2, P-based fertilizer (reference fertilizer – triple superphosphate) was produced from primary sources – phosphate rock.
The results of the LCA showed that both processes contribute to a potential environmental impact. The overall results showed that the production process of P-based fertilizer aff ects the environment primarily through the use of the P raw materials. The specifi c results showed that the highest impact on the environment was obtained for the Scenario 2 (1.94899 Pt). Scenario 1a and 1b showed the environmental benefi ts associated with the avoiding of SSA storage and its emissions, reaching -1.3475 Pt and -3.82062 Pt, respectively. Comparing results of LCA of P-based fertilizer production from diff erent waste streams, it was indicated that the better environmental performance was achieved in the scenario 1b, in which SSA had the higher content of P (52.5%) in the precipitate. In this case the lower amount of the energy and materials, including phosphoric acid, was needed for the production of fertilizer, calculated as 1 Mg P2O5. The results of the LCA may play a strategic role for the decision-makers in the aspect of searching and selection of the production and recovery technologies. By the environmental evaluation of diff erent alternatives of P-based fertilizers it is possible to recognize and implement the most sustainable solutions.
Due to the lower energy consumption and waste production compared to traditional methods, the environmental bioremediation methods based on natural processes have been gradually becoming more prevalent in environmental engineering. Biological methods are used in waste management, wastewater treatment, gas treatment or soil remediation. For the low solubility of some pollutants and lower bioavailability, the use of biological methods may be hampered. This problem might be mitigated with the use of surfactants. This paper presents the results of studies regarding the eff ect of dosing a selected surfactant from the Tween group (Tween 20) on the efficiency of toluene elimination from the air by biofi ltration. The obtained maximum biofi ltration rate was 21.2 g/m3/h and 19.8 g/m3/h for the control bed and for the bed to which the Tween 20 solution was dosed, respectively. The eff ect of Tween was neutral (the effectiveness of toluene removal was insignificantly comparable to the effectiveness of the control series), it did not affect the effectiveness or limited the development of the biofilter microflora.
Results of fly ashes from combustion of hard coal and co-combustion of alternative fuel (SRF) with coal in the stoker boiler WR-25 type studies have been shown. Samples of fly ashes were acquired during industrial combustion tests of hard coal and blend of coal with 10% SRF. The scope of comparative research included: chemical composition, contents of combustible parts and trace elements and also of microscopic analysis. The specific surface area SBET was established and tests of water extract were conducted. Chemical composition of mineral substance of both studied ashes is similar. Main ingredients are: SiO2, Al2O3, Fe2O3 and CaO. Fly ash from co-combustion of SRF with coal in a stoker boiler is characterized by high contents of combustible parts (on 30% level), higher than ash from hard coal combustion. Both tested ashes are characterized by specifi c surface area SBET on the level of 8–9 m2/g. In porous structure mesopores are dominant (>60%), and their volume is higher for fly ash from co-combustion of SRF with coal. Fly ash from co-combustion of waste is characterized by high contents of heavy metals. Nevertheless these metals and also other pollutants do not show leachability exceeding acceptable values for wastes different than hazardous. The microscopic structure of fly ashes from combustion of hard coal and co-combustion of alternative fuel studies showed crucial differences, especially in reference to organic material. Presented research results have shown that fly ash from co-combustion of SRF with coal in a stoker boiler can obtain the status of non-hazardous waste.
The article presents the results of preliminary tests obtained from the analysis of ash coming from the combustion of various types of waste in household furnaces. The aim of this work was to examine the infl uence of various types of waste burned in household furnaces on the elemental composition of the generated ash. As part of the research, analyses of ash generated from the incineration of mixed waste, plastics, wood, textiles, rubber waste and paper were made. The content of selected metal ions: Mn, Cu, Mo, Zn, Cd, Tl, Cr, Co, Ni, As, Sn, Sb, Pb, V was determined in the tested samples, according to PN-EN ISO 17294-2: 2016-11 standard. The highest concentrations of zinc were found in the large-sized waste, rubber and textile ash samples and highest concentrations of copper were found in the plastic and paper ash samples. The highest concentrations for elements such as copper, lead, cobalt and chromium were recorded for samples of rubber and large-sized waste containing e.g. varnished furniture boards. The obtained results showed that depending on the waste incinerated, the content of selected metals was signifi cantly diff erent, and the highest concentrations were noted for samples of large-sized waste, waste from segregated plastics and waste from rubbers.
The research was intended to develop a biocomposite as an alternative biodegradable material, for the production of, e.g., disposable utensils. The author’s tested thermoplastic maize starch, both without additives and with the addition of crumbled fl ax fi ber in the share of 10, 20 and 30 wt%. The plasticizer added was technical glycerin and the samples were produced by a single-screw extruder. The mechanical strength tests were performed, including the impact tensile test and three-point bending fl exural test. Afterwards, the samples were tested for biodegradability under anaerobic conditions. The methane fermentation process was carried in a laboratory bioreactor under thermophilic conditions with constant mixing of the batch. All samples proved to be highly susceptible to biodegradation during the experiment, regardless of the fl ax fi ber share. The biogas potential was about 600 ml·g-1, and the methane concentration in biogas ranged from 66.8 to 69.6%. It was found, that the biocomposites can be almost completely utilized in bioreactors during the biodegradation process. The energy recovery in the decomposition process with the generation of signifi cant amount of methane constitutes an additional benefi t.
This paper presents the results of a fi eld study on using mineral materials (fine-grained sand and medium-grained gravel) to reduce the concentration of readily soluble salts in a roadside environment. The investigated soils were Rendzic Sceletic Leptosols from an urban area characterized by a shallow humus horizon with a high content of skeletal parts, as well as a lack of homogeneity of the material in the soil profile. All soil samples were taken from five plots located along the main streets in the city of Opole (Southern Poland). It was revealed that the use of fine-grained sand and medium-grained gravel improved the structure of the surface soil layer, and thus favoured the migration of Na+ and Cl- ions into the soil profile. In comparison to control surfaces readily soluble salts were reduced with gravel and sand application. Furthermore, the mineral materials introduced on the soil surface for salinity neutralization did not affect the quality of the tested roadside calcareous soils. The results indicate that the use of mineral materials reduces soil salinity caused by NaCl. They also show the need to find new methods of salt neutralization, especially of roadside soils in order to improve and protect the quality of the environment.
Non-point source pollution is a primary cause for concern globally. Various models have been developed to tackle this situation with much emphasis placed on best management practices. This practice has, however, proven to be insufficient to solve the NPS pollution situation. Existing non-point source models are watershed-based and complicated both in operation, parameter estimation and data requirements. A non-point source model is proposed using the concept of the Hybrid Cells in Series model. The model is a three-parameter model made up of three zones, which describes pure advection through time delay in a plug zone, with combined advection and dispersion occurring when the other two zones are considered as thoroughly mixed. The proposed model is tested using synthetic data and fi eld data from the Snake River, Colorado, USA, obtained from literature. Simulations were performed at four sample points; two from the tracer injection point along the Snake River before a confluence and two further downstream after the confluence. A regression analysis was carried out to determine the model’s capability to simulate pollutant transport for the four sampling points. The coefficients of determination are 0.98, 0.94, 0.84 and 0.97 while the standard error for each reach is 2.28E-2, 2.70E-2, 2.32E-2 and 9.35E-3 respectively. The results show good agreement between the measured and the simulated data. The response of the C-t profiles produced by the proposed model for both synthetic and field data demonstrates its ability to effectively simulate pollutant transport in natural rivers subject to non-point source pollution.
This article presents results of research concerning the possibility of reducing the level of toxic nitric oxides (NOx) emission to the atmosphere. The research has been conducted on DKVR 20-13, PTVM-50 and DE 25-14 gas boilers. The complex character of this issue requires individual consideration regarding each boiler configuration. Each case requires consideration of characteristics and details of all elements constituting the boiler-furnace unit. The main problem was to establish the reference level to which the reduction of nitric oxides occurs. The actual maximum emission of nitric oxides was assumed as this level. It was verified with the maximum allowable emission of nitric oxides for each boiler. Three levels of the potential influence of emission on the atmosphere have been taken into account. This experimental research allowed for proposing an effective method, which led to reducing nitric oxides emission by around 30%.
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