Search

Creation of oxygen-containing functional groups on the biochar surface can highly improve its hydrophilicity and amend its behaviour in aquatic systems. Hydrogen peroxide, ozone, potassium permanganate and nitrogen acid were most usually used reagents for the surface oxidation. On the contrary, biochar activation by strong acids can be a costly process at the industrial scale and can raise environmental problems due to the disposal of activated carbon. Hence, there is a need to search for cheaper and cleaner products for the modification of biochar. For this reason, weak acids, such as solution of rhamnolipids or rainfall water solution, can be used. In this study, it was found that lower size biochar particles had higher wettability compared to larger size particles, since it was categorized as slightly hydrophobic (2.67 s). Steam of average concentration of rhamnolipid solution (20 mg/l) had the highest effect on the enhancement of biochar surface area (15.2 m2/g) and satisfactory impact on the reduction of initial hydrophobicity (4210 s). Biochar modified with increased concentration of nitric acid solution (from 65 to 20%) wettability was in accordance with the increase of surface area (from 4210 to 3907 s and from 1.27 to 4.36 m2/g).

In this study, Mn-based multicomponent catalysts supported by two different carriers (lightweight expanded clay aggregate and the Ukrainian clinoptiolite) were prepared by electroless metal deposition method and tested for the selective catalytic reduction of NO with ammonia (NH3-SCR de-NO). Prior to the activity test, all the catalysts prepared were characterized by inductively coupled plasma optical emission spectroscopy, field emission scanning electron microscopy (FESEM), energy dispersive X-ray mapping, X-ray photoelectron spectroscopy, H2-TPR and NH3-TPD techniques. The particular interest of the present study was focused on the investigation of the carrier's role in the NO catalytic reduction and the promoting effect provided by the incorporation of the small amount of Pt (0.1 wt.%) in the Mn-based catalytic layer. The results revealed that the carrier's role in the NO catalytic conversion can be considered as a factor determining the effectiveness of the conversion process. Ukrainian clinoptiolite was proved to be a more attractive carrier for the preparation of the effective SCR de-NO catalysts due to its intrinsic sorption capacity, surface acidity and the redox potential. The high NO conversion efficiency provided by the Mn-based clinoptiolite-supported catalysts can be explained by the synergistic effect between the carrier and the active species deposited. It was shown that both the Mn97.6Cu2.4/clinoptiolite and the Mn97.5Co2.5/clinoptiolite catalysts can be successfully applied as the low-temperature (100-300°C) catalysts for NH3-SCR de-NO. When the NO removal efficiency varies in the range of 86-91%, the additional incorporation of Pt in the active layer in the amount of 0.1 wt.% can enhance the NO reduction by about 5% on average.

Environmental issues near roads become more and more important in our society daily life. One of the most critical environmental issues is traffic noise. The present paper study louvred noise barrier designed by authors. The louvred noise barrier provides sound attenuation while allowing airflow and sunlight through it. Since the airflow resistance of the barrier is low, it requires a shallow foundation compared to conventional noise barriers. The sound attenuation performance of the louvred noise barrier was tested experimentally in a sound transmission chamber. Airflow resistance simulated using a computational fluid dynamics model. The simulation and experimental study were done with different louvred noise barrier setup: change of louvre blade angle and sound-absorbing material thickness. The results showed potential for future development for the field testing. Sound attenuation was highest in 2500 Hz and 3150 Hz octave frequency bands. Depending on the louvred barrier setup, sound attenuation was up to 28 dB(A) in mentioned frequency bands. The equivalent sound pressure level reduced up to 17 dB(A). The results showed that an increase in the louvre blade angle increases sound attenuation and increases airflow resistance.

The aim of the study was to evaluate the performance of two newly developed plate-type biofilters in treating air contaminated with ammonia vapour at different inlet air temperatures (24, 28, and 32 °C). The biofilters had two different structures, straight lamellar plates (SLP) and wavy lamellar plates (WLP), with both having a built-in capillary system for humidifying the packing material made of synthetic hydrophilic fibres and wood fibre. In the packing material of the biofilters, different types of microorganisms were used, including bacteria, micromycetes and yeast. The efficiency of ammonia removal from the air using the biofilters with the two different plate types was investigated. The treatment efficiency of air-containing ammonia vapour reached 81.0–85.2% and 84.2–87.0% in biofilters with SLP and WLP, respectively. The highest ammonia treatment efficiency was obtained in the biofilter with WLP at 28 °C with 87.0% of ammonia being removed. The latter removal efficiency was obtained when a large population of the microorganisms was present with 1.0 ± 0.2 × 107, 1.0 ± 0.5 × 107 and 1.6 ± 0.1 × 109 CFU/g of micromycetes, yeast and bacteria, respectively. The results also demonstrated that at different temperatures of polluted air, different microorganisms predominated in the packing material of the biofilters.

In this study, different types of magnetic biochar nanocomposites were synthesized using the co-precipitation method. Two biochar materials, namely, sewage sludge biochar and woodchips biochar, were prepared at two different temperatures, viz., 450 and 700 °C. These biochars were further modified with magnetic nanoparticles (Fe3O4). The modified biochar nanocomposites were characterized using field emission–scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM), Brunauer–Emmett–Teller (BET), SQUID analysis, X-ray photoelectron spectroscopy (XPS), and Fourier-transform infrared spectroscopy (FTIR). The potential of prepared adsorbents was examined for the removal of hexavalent chromium (Cr(VI)) and Acid orange 7 (AO7) dye from water as a function of various parameters, namely, contact time, pH of solution, amount of adsorbents, and initial concentrations of adsorbates. Various kinetic and isotherm models were tested to discuss and interpret the adsorption mechanisms. The maximum adsorption capacities of modified biochars were found as 80.96 and 110.27 mg g-1 for Cr(VI) and AO7, respectively. Magnetic biochars showed high pollutant removal efficiency after 5 cycles of adsorption/desorption. The results of this study revealed that the prepared adsorbents can be successfully used for multiple cycles to remove Cr(VI) and AO7 from water. Graphical Abstract Electronic supplementary material The online version of this article (10.1007/s11356-020-09275-1) contains supplementary material, which is available to authorized users.

The efficiency of a semi-continuous three-stage bioreactor and application possibilities of a chicken manure substrate with birch wood biochar additive (10% by a dry mass) were investigated in this...

In the present work, granular fixed-bed catalysts with active Cu–Mn and Cu–Mn–Nb layers synthesized by electroless metal deposition method were prepared and tested for purification of a flue gas from nitrogen monoxide (NO) by CO. Lightweight expanded clay aggregate with i.d. of 2–4 mm and 8–10 mm was used as a substrate for deposition of the active layer. Elemental composition of the prepared catalytic layers was determined by means of inductively coupled plasma optical emission spectroscopy and energy-dispersive X-ray analysis. Field emission scanning electron microscopy and X-ray photoelectron spectroscopy were applied to investigate morphology of the active layers and the oxidation state of the main components (Mn, Cu and Nb), respectively. Additionally, X-ray diffraction analysis and energy-dispersive X-ray mapping were conducted to provide comprehensive information about the structure and dispersion of active components on the surface of the catalysts prepared. It was demonstrated that electroless metal deposition method allows preparation of a relatively uniform active layer with highly distributed active sites on the substrate surface, while the Cu0.012–Mn0.986Nb0.0012 active layer synthesized by electroless metal deposition can be successfully applied for selective catalytic reduction of NO with the use of CO as a reductant. The effective NO conversion (90–95%) was observed at temperatures of 300–400 °C and higher. X-ray photoelectron spectroscopy revealed that significant amount of Mn3+ and Mn4+ species and predominance of chemisorbed oxygen over the lattice oxygen should be responsible for NO conversion efficiency of the catalyst prepared.

The present work is dedicated to the investigation of NOx removal from flue gases, in particular to NOx catalytic reduction by CO using monolith corrugated cylindrical Cu-Cr-based catalysts prepared by plasma spray coating technique. X-ray photoelectron spectroscopy was conducted to provide comprehensive information about oxidation states and chemical forms of main active components of the catalysts prepared. Investigation of NOx catalytic reduction was carried out under different initial oxygen concentrations (0.0–0.1%, 0.6–0.7% and 1.2–1.3%) and gas flow velocities (0.1, 0.3 and 1.0 m/s) using different amount of catalysts and providing different residence time in the range of 0.1–3 s. The NOx conversion achieved at 0.0–0.1% oxygen concentration was 50%, 75% and 88% for the residence time of 1 s, 2 s and 3 s. The corresponding NOx conversion observed at the O2 concentration of 0.6–0.7% was 37%, 60% and 70%. However, investigated Cu-Cr-based catalysts were found as ineffective at initial oxygen concentrations higher than 1% regardless the residence time. The dependence of NOx conversion on residence time in general was represented by logarithmic regression and can be described by the following formula y = 23.962 ln(x) + 56.575, where “y” is NOx conversion degree (%) and “x” denotes the residence time. It was demonstrated that NOx conversion efficiency decreases along with increasing the gas flow velocity, which can be explained by reduction of residence time of a gas flow inside the catalysts. However, the obtained results revealed that using different gas flow velocities and providing the same residence time by changing the amount of catalysts, different NOx conversion was observed. In particular the degree of NOx reduction obtained at the gas flow velocity of 1 m/s was much lower than that achieved by applying lower gas flow velocity (0.3 m/s) regardless the residence time was the same. The negligible NOx reduction was found for all cases when the gas flow velocity of 1 m/s was used. Therefore, it was supposed that the gas flow velocity of 1 m/s does not ensure the required mass transfer between the gas components and catalyst’s surface inhibiting the catalytic reaction to take place and resulting in extremely low NOx conversion.

The present study aims at removal of Cr(VI) using immobilized Limnococcus limneticus from synthetic wastewater. Four different methods were followed to immobilize test cyanobacterial strain onto ca...

Availability of clean water and sustainable management of water are among the 17 global ‘Sustainable Development Goals,’ established by the United Nations. The increasing technogenesis-related pollution causes increases the concentrations of many metallic elements (MEs) throughout the biosphere. The syngenetic bio-incorporation of MEs changes the biomass's chemical and physical composition and impacts the quality of products, e.g. biochar (BC). This has impacts upon BCs potential for adsorption of water pollutants. While direct, engineered modification of BC can improve its adsorption characteristics, the more indirect alterations of BC composition, based on syngenetic elements, also modifies BCs adsorption functionality. The objective of this study was to identify the characteristics of syngenetically accumulated MEs in ligneous biomass on the adsorptive properties of the BCs derived from such modified biomasses. The authors of this paper investigated the syngenetic pathway of MEs into the ligneous biomass and provided an overview of the forms and quantities of MEs in the biomass and their transformation to BC. The early results of the effects of syngenetic MEs on the adsorptive properties of BC from ligneous biomass are presented. The results suggest that additional syngenetical MEs result in increases in the adsorptive properties of the resultant biomass-derived BCs.

A significant proportion of pollutants arise from the heat production equipment in private households. The processes of combustion and product treatment (drying, adding chemical compounds) generate aggressive gas flows containing solid particles (SPs). Common methods employ high-efficiency gas purification to remove SPs, the most popular include electrostatic and sleeve-type filters. However, the operation of these types of filters is complex, and thus their application is very limited. This is especially evident when collecting adhesive and wet FSPs or when purifying aggressive gas flows. New design multi-channel cyclone has a few principal elements of the structure such as secondary inlets, inner slits and convex bottom. These improvements allow to avoid an adhesion of sticky and moist SPs on the inner surfaces of the cyclone. This study focuses on estimating the effect of separating wood and wood ash SPs. The obtained results are presented and the comparison of the advantages and disadvantages of two different design multi-channel cyclone are provided.

In this study, Mn-based multicomponent catalysts supported by two different carriers (lightweight expanded clay aggregate and the Ukrainian clinoptiolite) were prepared by electroless metal deposition method and tested for the selective catalytic reduction of NO with ammonia (NH

Based on the air quality in Europe - 2019 report of European Environment Agency, nitrogen oxides (NOx) are included to the most harmful air pollutants in terms of damage to ecosystems. Moreover, NO2 is one of the most Europe’s dangerous pollutants to human health. Anthropogenic emissions of NOx are mainly generated by combustion of fossil fuels. Nitrogen oxides being emitted into the atmosphere cause such environmental problems as acid rains, acidification of soil, lakes and rivers, eutrophication and photochemical smog. The most effective and widely used technology achieved for today to purify flue gases from NOx is selective catalytic reduction using ammonia (NH3-SCR de-NOx). Nowadays, one of the most significant directions in the field of NH3-SCR de-NOx is applying of new nonconventional methods and preparation of new catalysts possessing high specific surface area, uniformity, dispersion of active sites, high activity and selectivity. Atomic layer deposition (ALD) is an attractive technique for deposition of uniformly distributed active catalytic layers or nanoparticles on highly porous substrates being characterized by a complex structure and highly developed surface, where the application of conventional methods (e.g. impregnation or deposition precipitation) can be problematic. The significant advantage of ALD application for preparation of supported catalysts is that the preparation process can be controlled on the atomic scale providing the required thickness of an active layer synthesized with accuracy of up to one atom. Moreover, ALD ensures the formation of catalysts in a gas phase instead of a liquid phase, which enhance the possibility of active species to be deposited inside pores which are very small in size. In this study ALD was applied for preparation of VxOy-based NH3-SCR de-NOx catalysts. Highly porous silica gel powder (63-100μm) with a specific surface area of up to 450 m2·g-1 was used as a substrate for active layer deposition. VxOy/SiO2 with different metal loadings (wt.%) and (VxOy+TiO2)/SiO2 catalysts were prepared by applying the following metal precursors: vanadium (V) tri-i-propoxy oxide (VTIP) and titanium tetrachloride (TiCl4), while deionised water was used as the co-reactant. ICP-OES results revealed that vanadium loadings in VxOy/SiO2 catalysts were 0.3, 0.7, 1.1 and 1.6 wt.%, while the metals loading in the TiO2-promoted VxOy/SiO2 catalyst was 1.04 wt.% and 0.15 wt.% for V and Ti, respectively. According to XPS spectra V2O3 and V2O5 species were identified in the prepared VxOy/SiO2 catalyst with the predominance of vanadium (V) compounds (V2O5/V2O3 ratio was 1.6 and 6.3 for as-synthesized and calcined samples, respectively). V2O5 is found as an active vanadium form for NH3-SCR de-NOx. Additionally, TEM, XRD and BET analyses were conducted to provide a comprehensive characterization of the catalysts prepared.

The equipment used for the analysis of the aerodynamic characteristics of biological air treatment systems (e.g. air flow velocity and aerodynamic resistance) as well as the results of experimental research of biofiltration systems with natural materials and nature-based phenomena are described in this chapter. By considering the cases of biofiltration systems, it is demonstrated how engineering solutions can be used to the most efficient performance of the components ensuring the sustainability of the systems. The results obtained in the investigation of air treatment efficiency for organic pollutants (i.e. ammonia, acetone and xylene) are presented. The developed theoretical models of the performance (e.g. aerodynamic processes) of designed biofilters are presented.

This chapter presents the effect of natural (favoured by natural microorganisms) and engineered (governed by introduced microorganisms) phenomena on sustainability of biofiltration system constructed using natural materials for microorganism substrate. The results obtained in studying activities of microorganisms to produce cellulose and xylanase needed for lignocellulosic component hydrolysis as well as the provision of the load’s microorganisms with nutrients and the selection and the properties of microorganisms (i.e. bacteria, microscopic fungi and yeast) for effective biofiltration are presented in this chapter. The influence of such parameters as temperature and pH on the activities of the biofiltration system’s microorganisms as well as generated odours and their measurements by using the olfactometric method are described.

This chapter continues the description of the third sustainability level and features of environmental protection technologies with the example of biofiltration systems. Attention is given to the natural materials used in biofiltration systems to better sustain the technological performance. The analytical equipment used in the study of physical properties of the loading of the biological air treatment systems and the lab-scale biological air treatment systems are described in this chapter. Besides, the results of studying the influence of the moisture of the loading material of the filters and the conduction for the gas stream as well as the air cleaning effectiveness, temperature, acidity (pH) and oxygen distribution within the load are presented.

This chapter continues a discussion on the second sustainability level of environmental protection technologies and focuses on the use of natural materials for removing pollutants (for example, potentially toxic elements) from the aqueous media. This chapter describes PTEs found in waters and the use of biochar as a sustainable material for removing them. This part of the book looks into the adsorptive capacity of biochar and the effectiveness of contaminant removal subject to its type and the characteristics of the adsorbable material. Moreover, the influence of biochar composition as an adsorbent on its capacity is analysed with respect to syngenetic elements.

The chapter discusses the major trends in technogenesis that caused the contamination footprint in the twenty-first century, defines the concept of the contamination footprint and the methods for evaluating it as well as formulates the concept and role of biogeochemical and engineered barriers forming a part of sustainable natural and engineering environmental protection technologies for decreasing the contamination footprint caused by technogenesis. The fundamental framework comprising the classification of biogeochemical and engineered barriers and their description is provided. The chapter explores the sustainability of environmental protection technologies at three levels, including natural technologies, the analysis of using natural materials in environmental engineering systems and the components ensuring the sustainability of environmental engineering systems.

The development of sustainable technologies from the laboratory to the pilot scale and the modelling in the case of biofiltration systems is presented in this chapter. A description of aerodynamic, physical and sorptive characteristics of the loads, their efficiency and microbiological characteristics in biological air treatment systems is given. The design of the developed biological air treatment filters of the plate and tubular types with the capillary load irrigation system and the conditions of their application are analysed.

The chapter provides the classification of barriers. The position of natural and artificial biogeochemical barriers in this classification is defined as an example of the first-level sustainability of environmental protection technologies. The role of the barriers is shown considering the bio-accumulating properties of the ligneous and phytoremediation capacity of gracious plants. The chapter also discusses the application of the method for dynamic factors used for assessing the risk of contamination and the effectiveness of the considered barriers. The obtained results are discussed based on the studies into real operational conditions for waste incineration and oil refining plants.

In this chapter the third level of sustainability of environmental protection technologies is presented with the example of biological treatment of air. The major principles and applications of the method of biological air treatment, the loadings used, their characteristics and influence on air cleaning effectiveness, as well as the analysis of biological air treatment facilities and their influence on air cleaning effectiveness are discussed in this chapter. The method used in the study of physical and aerodynamic characteristics of the loads includes the factors supporting the activities of microorganisms oxidizing volatile compounds found in the biological air treatment systems and their characteristics. Theory of biological treatment principles is analysed and the models describing biofiltration processes and the simulation programs of the processes are presented.

The use of sustainable natural materials in environmental engineering systems is presented as the second sustainability level of environmental protection technologies. This chapter focuses on employing such materials in the stabilization of soil pollution and waste management, explores biochar produced from various kinds of waste materials containing potentially toxic elements (e.g. sewage sludge and waste from paper manufacturing), deals with a comparative analysis of its properties, presents research into the stability of potentially toxic elements found in biochar, evaluates environmental risk and discusses the results of investigating the use of biochar for stabilizing metallic elements in the polluted soils and the effect of biochar on the bioavailability of these elements in the soil.

A multi-channel cyclone is a new-generation cleaning device, which purifies a gas flow by removing fine dispersion solid particles of 2 μm and larger in diameter from it. An aggressive dispersed gas flow can be formed under various conditions, for example, in combustion and processing of various products such as drying of chemical compounds, etc., at high temperature and/or high humidity. Multi-channel cyclones of a new generation have a number of advantages over the most widely used equipment for separating the particulate matter from the air flow such as electrostatic and bag filters, which are rather expensive, difficult to maintain and to be used for separating sticky and moist particles from the aggressive gas flow. The paper examines wood and lignin solid particles of different nature and properties present in a gas-vapour flow. Their adhesion and cohesion, depending on the time of the multi-channel cyclone operation aimed at purifying a dusted gas-vapour flow at high gas-vapour temperature and humidity are investigated. The research is aimed at determining the optimal separation efficiency and the aerodynamic parameters of a multi-channel cyclone and their variation by creating an aggressive dispersed gas flow. It assesses the detrimental effect of the deposition of wood and lignin solid particles on its interior surfaces, their cohesion and adhesion and clogging the system. The efficiency of the cyclone's operation is investigated for the flow, moving at medium rates and containing solid particles of various sizes. The highest cyclone's efficiency is determined for its separation of medium- and small-size solid particles. The theoretical study of kinematic and dynamic gas flow viscosity and the calculation of its coefficients as well as the dew point temperature of the flow are performed and the relationships between them are determined. The obtained results are presented and some recommendations for improving the structure of a multi-channel cyclone for separating sticky and moist particles from a humid and hot gas flow are provided.

The analysis of the two-level multi-channel cyclone operation requires the investigation of the treated air flow movement. The two-level multi-channel cyclone was designed for separating solid particles from the air flow and constructed at the Institute of the Environmental Protection of Vilnius Gediminas Technical University. The study was aimed at determining airflow distribution in a two-level six-channel cyclone and measuring air treatment efficiency. To determine the velocity of airflow in the channels, a multi-functional measuring instrument Testo-400 and the dynamic Pitot tube were used. The concentration of particles in the air inlet and outlet ducts was determined by the weight method. The obtained results showed that the same air volumes on both cyclone levels are equal and the velocity of the airflow was uniformly distributed in the channels. The maximum airflow velocity was recorded in the first channel. The mean airflow velocity in the channels did not differ significantly.

Dissolved organic carbon (DOC) interacts with dissolved trace metal affecting their mobility and bioavailability through the formation of DOC–metal complexes. Several types of biochar (BC) produced from slow pyrolysis of wood chips (WC), lignin (LG), and digested sewage sludge at 450 and 700 °C were tested for DOC leaching via batch and up-flow percolation test methods. Trace metal (Cd, Cu, and Pb) speciation modelling in BC eluates was carried out combining measured data (i.e., DOC, ph, temperature, and dissolved trace metal concentrations) with data reported in the literature regarding fractions of DOC that are inert or active (i.e., fulvic acids (FA) and humic acids (HA)) in metal binding. BC from LG (BCLG) and WC (BCWC) at 700 °C released lower cumulative amounts of DOC compared with BC at 450 °C in the range 0.02–0.07% and 0.06–0.09% of total carbon content, respectively. For both pyrolysis temperatures, BCWC exhibited a higher tendency to release DOC compared to BCLG. Speciation modelling results showed the predominance of FA and HA complexes of Cd, Cu, and Pb in all the eluates from BCWC and BCLG irrespective of the inert fractions of DOC or the different fractions of active FA and HA considered.

The examined equipment is a batch bioreactor intended to produce biogas from sewage sludge, vegetal and other organic wastes. The maintenance of an optimal temperature and oxygen concentration inside the devise, as well as the intensity of mixing a substrate, result in methane CH4 actively generated by methanogenic bacterial colonies. Manufacturing biotechnologies and biogas deal with environmental protection, energy and economic problems. For research purposes, considering organic loading (hereinafter, VS/L), four different types of the packing material of sewage sludge, including VS/L = 3.5 g L-1, VS/L = 5.0 g L-1, VS/L = 10.0 g L-1 and VS/L = 15.0 g L-1, were used. The highest concentration of CH4 (75.1%) and yield of biogas (36.78 L d-1) were found using a packing material, the organic loading of which made 15.0 g L-1. Throughout the experiment, the temperature of the mesophilic process reached 35-37°C, and the concentration of oxygen was 0.0-0.1%. The research carried out has disclosed the dependencies of the components of biogas on the number of the days of the performed experiment. With reference to experimental research conducted at the laboratory, a small-sized batch bioreactor can be designed and successfully used in a small farm.

Special cyclone – gas treatment device which can be applied to remove the fine particulate matter bigger than 2 micrometres from aggressive gas flow at a temperature of 50–145 °C and a relative humidity of more than 95% and can be achieved the cleaning efficiency over 90%. Cyclone work is based on centrifugal forces and the resulting additional filtration process operation. Cyclone structure equipped with primary and secondary gas flow inflows through which gas dispersed flow is supplied parallel to all channels of the cyclone. Analysed modified multi-channel cyclone can be effectively treated from fine particulate matter, during the cleaning of aggressive gas flow an adhesion/cohesion phenomena could be reduced. Research of aerodynamic parameters it’s the first step of studies to determine the optimal case, at the average gas flow velocity in cyclone channels were 8, 12 and 16 m/s, the gas flow dynamics dependencies into cyclone were determined. Article in Lithuanian. Specialaus ciklono su antriniais srautais aerodinaminių parametrų tyrimai Santrauka Specialus ciklonas-dujų valymo įrenginys geba pašalinti iš užteršto agresyvių dujų srauto, kurio temperatūra 50–145 °C ir santykinis drėgnis daugiau nei 95 %, smulkiadisperses kietąsias daleles nuo 2 µm dydžio bei pasiekti didesnį nei 90 % valymo efektyvumą. Įrenginio darbas pagrįstas išcentrinių jėgų bei papildomai atsirandančio filtracijos proceso veikimu. Ciklono konstrukcijoje įrengti pirminis ir antriniai įtekantys dujų srautai, per kuriuos oro dispersinis srautas patenka lygiagrečiai į visus ciklono kanalus. Tiriamas patobulintas daugiakanalis ciklonas, kuris efektyviai išvalytų iš srauto smulkiadisperses kietąsias daleles, sumažintų adheziją ar autoheziją valant agresyvių dujų srautą. Aerodinaminių parametrų tyrimai – pirmasis šio įrenginio tyrimo etapas, siekiant nustatyti optimalius atvejus esant 8, 12 ir 16 m/s vidutiniams dujų srauto greičiams ciklono kanaluose bei dujų srauto dinamikos priklausomybes ciklone. Reikšminiai žodžiai:daugiakanalis ciklonas; antriniai srautai; aerodinaminiai parametrai; kietosios dalelės.

Biogas – ecological fuel, which is assigned to alternative energy sources. It should be noted, that biogas – renewable energy source, which does not require any specific climatic conditions or geographical position of a country. This power source is available and can be successfully produced and used in all countries of the world. The main components of biogas – methane CH4 and carbon monoxide CO2. This gas is formed under anaerobic conditions, when microorganisms decompose biodegradable biomass. In biological sciences biomass means a living matter content, expressed in grams per unit area. Meanwhile, in the energy sector, the definition of biomass is limited and biomass is characterized as fuel source, produced from plant materials and organic waste (food waste, wood, sludge, manure, vegetables, etc.). Currently, to produce biogas from biomass, bioreactors are used worldwide. However, in order to increase the quality and yield of biogas, in the world practice various bioload additives are used: vegetable waste, clay minerals, and a large amount of the protein-containing waste. The goal – to evaluate the impact of biochar on biogas quality and yield using sewage sludge load. It was found, that 10% biochar additive increased average CH4 concentration of 7.9%, reduced the CO2 concentration of 3–4% and totally removed H2S from biogas. Article in Lithuanian. Biodujų gamybos eksperimentiniai tyrimai taikant nuotekų dumblo įkrovą su bioanglies priedu Santrauka Biodujos – ekologiškas kuras, kuris priskiriamas prie alternatyvios energijos šaltinių. Pažymėtina, kad biodujos – atsinaujinantis energijos šaltinis, nereikalaujantis jokių specifinių klimato salygų ir nepriklausantis nuo šalies geografinės padėties, t. y. šis energijos šaltinis yra prieinamas ir gali būti sėkmingai gaminamas bei naudojamas visose pasaulio šalyse. Pagrindinės biodujų komponentės – metanas CH4 ir anglies monoksidas CO2. Šios dujos susidaro esant anaerobinėms sąlygoms, kai mikroorganizmais yra skaidoma biomasė. Biologijos moksluose biomasė traktuojama kaip gyvos medžiagos kiekis, išreikštas gramais per ploto vienetą. O energetikos sektoriuje biomasės apibrėžimas yra ribojamas ir biomasė charakterizuojama kaip kuro šaltinis, susidarantis iš augalinių medžiagų ir organinių atliekų (maisto atliekos, mediena, dumblas, mėšlas, augalinės kilmės atliekos ir pan.). Šiuo metu pasaulyje biodujoms iš biomasės pagaminti naudojami bioreaktoriai. Tačiau siekiant padidinti biodujų kokybę ir išeigą, pasaulinėje praktikoje naudojami įvairūs bioįkrovos priedai: augalinės kilmės atliekos, molio mineralai bei didelį kiekį baltymų turinčios atliekos. Šio darbo tikslas – įvertinti bioanglies priedo įtaką biodujų kokybei ir išeigai naudojant nuotekų dumblo įkrovą. Nustatyta, kad 10 % bioanglies priedas padidino CH4 vidutinę koncentraciją 7,9 %, sumažino CO2 koncentraciją 3–4 % ir sumažino H2S koncentraciją iki 0 ppm. Reikšminiai žodžiai:bioreaktorius; biodujos; bioįkrovos priedai; nuotekų dumblas; bioanglis.

Purpose This purpose of the paper is to examine the multi-channel cyclone created at the Vilnius Gediminas Technical University (VGTU) Research Institute of Environmental Protection. The paper aims to predict the possible trajectories of solid particle motion in the cyclone with reference to the mechanical forces only. Design/methodology/approach The numerical calculations were performed on the basis of experimental results. The system of differential equations describing particle motion in the cyclone is analysed and numerically solved using Runge–Kutta–Fehlberg method. Research consists of three examples that illustrate the impact of particle density and velocity on collection and analyses the particle motion trajectories in the first and second channels of the cyclone. Findings Numerical calculations were performed according to the data from Vilnius Gediminas Technical University Research Institute of Environmental Protection. The particulate matter of wood ash and granite were used. The collection of solid particles of different size was examined when the air inflow velocity varies from 10 to 20 m/s. The possible motion trajectories of the solid particles are defined and the parameters of collected particles have been discussed. Research limitations/implications The obtained results can be used for the analysis of air cleaning efficiency and particulate matter removal from air in a multi-channel cyclone. Practical implications The results lead us to improve the structure of the cyclone so as to effectively collect the solid particles of different size. Originality/value This paper presents the results obtained for the multi-channel cyclone created at the Vilnius Gediminas Technical University Research Institute of Environmental Protection.

Ultrafine particles are dangerous to human health and are usually difficult to separate from airflow because of their low inertia, which helps them to stick easily to surfaces because of adhesive forces. This characteristic provides opportunities for adhesive ultrafine particle separation by designing air-cleaning devices that exploit the sticking ability. To understand governing effects in such air-cleaning devices, which can be designed as multi-channel cyclones, the sticking of adhesive spherical glass particles under oblique impact has been investigated numerically by using the discrete element method. An adhesive dissipative contact model was applied by implementing different interaction forces for various-sized ultrafine pollutant particles. Normal loading is represented by the elastic Hertz contact model, whereas viscous damping is described by the modified nonlinear Tsuji model. The influence of deformation-dependent adhesive forces for a range of ultrafine particle sizes is illustrated during the sticking process. Dissipative oscillations during the sticking process were observed because of the influence of viscous damping forces.

The environmental legislation and strict enforcement of environmental regulations are the tools effectively used for developing the market of materials for environmental protection technologies. Sustain ability criteria shift environmental engineering systems to more sustainable-material-based technologies. For carbon-based medium materials in biofiltration, this trend results in attempts to use biochar for biofiltration purposes. The paper presents the analysis of biochar properties based on the main criteria for biofiltration medium integrating the environmental quality properties of biochar, following the European Biochar Certificate guidelines. Three types of biochar produced from feedstock of highly popular and abundant types of waste are analysed. A multi component approach was applied to summarize the results. The lignocellulosic type of biochar was found to be more competitive for use as a biofiltration medium than the types of biochar with high ash or lignin content. (C) 2016 Elsevier Ltd. All rights reserved.

Semi-continuous and periodic biogas production processes were investigated. Dry chicken manure containing 40.0 ± 0.5% volatile solids (VS) was used for the production of bioloading. Semi-continuous operation bioreactor and periodic bioreactor were used to implement research. Bioloading was additionally supplemented with newly prepared parts by removing 10% of decomposed mass and by adding the same amount of preheated mass every 7 days (semi-continuous process). The process was periodic when the mass was completely decomposed (after 45 days of the experiment) and fully removed (bioreactor was loaded with a new portion of raw material to 100% of the working volume again). Total duration of both experiments was 90 days. The results show that biogas production by semi-continuous process is more effective than periodic process due to higher total biogas yield (up to 39.7%) and higher methane yield (up to 33.5%). The maximum concentration of CH4 was determined during the periodic biogas production process, but the difference was only up to 2.1% (68.9% and 66.8%, respectively). Since the produced biogas had quite high average CO2 and H2 S concentrations (

Reducing the pressure drop in biofilters is important for the reduction of the energy consumption of these devices. Usually, the pressure drop increases with time due to the biomass growth within the packing material. The aim of this study was to evaluate the aerodynamic processes in a laboratory-scale wavy lamellar (WL) plate-type biofilter equipped with a capillary system for humidifying the packing material. The packing material of a designed biofilter consisted of wavy polymer plates (WPP) vertically arranged next to each other. The pattern of arrangement of the plates allowed sufficiently large spaces, and therefore, the use of such structure had an impact on a decrease in the pressure drop of the biofilter. WPP were coated with three different kinds of materials, namely (I) wood fiber (WF), (II) non-woven caulking material (NWCM) and WF, and (III) linen material (LM) and WF. The results showed that the composition of the packing material influenced pressure drop of the biofilter. The packing material, which consisted of WPP covered with WF, had the lowest pressure drop compared with the other two packing material compositions. In this study, the experimental results were also compared with the results of the performed mathematical modeling of airflow movement.

Removal of heavy metals through biosorption using biomass offers several advantages over other conventional techniques such as low cost, high efficiency, environmentally friendly, etc. In the present article, biosorption of Nickel(II) and Lead(II)was investigated using dried biomass of cyanobacterial consortium. OFAT (one-factor-at-a-time) analysis was used to assess the effect of input parameters on the removal of potentially toxic elements by varying initial metal ion concentration (2–10 mgL−1), adsorbent dose (0.1–1.0 gL-1), pH (for Pb(II): 2–6, for Ni(II): 2–8) and temperature (25°C–45°C) individually, at constant shaking speed of 150 ​rpm. Results showed that removal using biomass attained highest values in as short time as 15 ​min. The investigations also showed the removal is highly effective at lower initial concentrations of heavy metals. Maximum removal of Lead(II) (87.27 ​± ​1.75%) and Nickel(II) (92.57 ​± ​0.77%) was obtained at pH 6 and 45°C and at pH 7 and 25°C, respectively, within 15 ​min with 0.1 gL-1 biomass. Both the Langmuir model and Freundlich model were seen to fit the equilibrium data. Further, Artificial Neural Network was used to model the biosorption process. Subsequently, Particle Swarm Optimization was applied to optimize the operating conditions for the removal of both the metals.

Research into gas flow motion as a transported phase and pollutant – particulate matter (PM) is of crucial importance, their changes in particular areas of the object require knowledge of improving the apparatus. A cyclone is considered one of the most popular devices due to the new modified multi-channel design that involves combined separation and filtration phenomena. The findings of an accurate numerical model provide an opportunity to verify long-term experimental studies. In addition, it is possible to determine the impact of the designed principal elements of the structure comprising secondary gas inlets, inner slits and the convex bottom on gas and PM motion through verification conducting experimental research. The study focuses on simulating the upgraded cyclone using the SST k-omega model. The research has been conducted under the specified gas flow conditions such as high temperature and relative humidity (aggressive) gas and presents the results of the physical model to compare with. To achieve greater computational accuracy, a digital model of the cyclone made of specific volumetric elements has been developed thus expanding the grid and stepping to form the boundary zone. As a result, numerical simulation results differ by no more than 12.8% compared to the experimental studies results.

Changing the concepts of economic development and introducing new amendments can hardly decrease the accumulation in the soil of such pollutants as metals, remaining there for a long time. The predictive models for describing the balance of metals in the soil, which are based on the ‘atmosphere–plant–soil’ system and reflect the complicated physical–chemical nature of the metals’ migration, expressed by coefficients obtained in long-term observations in natural conditions, allow for evaluating long-term concentration of metals in the soil. The model BALANS evaluates self-purification of soil, taking into account the uptake of metals of aerogenic origin by the soil together with amendments, their physical–chemical migration and the type of microrelief determining its intensity as well as the absorbed biomass of plants and the removal of metals with crops. In this model, the half-period of metals’ washing out from the soil, found for the microrelief characteristic of low places, exceeds 200 years for Ni, Cr and Pb and makes 90 and 150 years for Zn and Cu, respectively.

A multichannel cyclone is new generation air treatment equipment that can remove fine stiff particles of up to 2 μm from air flow and reach the general effectiveness of 95%. The carried out research is aimed at establishing parameters for the dynamics of the gas–vapour two-phase flow in the cyclone and treatment efficiency removing stiff lignin particulate matter, i.e. under the increased humidity and temperature of the purified flow. The article describes the peculiarities of parameters for the cyclone—separator and analyses the results of the cyclones having different inner structures under conditions of an aggressive environment. The flow polluted with lignin particulate matter has been treated under simulation conditions in the laboratory, at the gas flow temperature of 28–30 °C and gas flow humidity of 85–95%. Under an average vapour-PM flow velocity of 12 m/s in the cyclone polluted with ultra-dispersive 20 μm lignin particulate matter and conditions of the aggressive environment, treatment efficiency equals 82.5%.

In the present study, we aimed to determine the changes of indoor radon concentrations depending on various environmental parameters, such as the outdoor temperature, relative humidity, and air pressure, in university building premises of different applications and heights. The environmental parameters and indoor radon concentrations in four different premises were measured each working day over an eight-month period. The results showed that the indoor radon levels strongly depended on the outside temperature and outside relative humidity, whereas the weakest correlations were found between the indoor radon levels and indoor and outdoor air pressures. The obtained indoor radon concentration and environmental condition correlations were different for the different premises of the building. That is, in two premises where the ventilation effect through unintentional air leakage points prevailed in winter, positive correlations between the radon concentration and outside temperature were obtained, reaching the values of 0.94 and 0.92, respectively. In premises with better airtightness, negative correlations (R = &minus, 0.96 and R = &minus, 0.62) between the radon concentrations and outside temperature were obtained. The results revealed that high quality air isolation in premises could be an important factor for higher indoor radon levels during summer compared to winter.

With the increase of urbanization and human consumption, the extraction of potentially toxic elements (PTEs) causes higher risk of them to enter sources of human food and potable water. Adsorption has been studied extensively as phenomena to reduce element mobility in both natural and engineered systems. The need to adapt the adsorption models to simulate the adsorption increases as the variety of adsorbents of natural origin is getting bigger and bigger due to their sustainability, availability and low costs. Adsorption of PTEs was analysed in the case of biochar which is a widely studied adsorbent, however, the studies are often limited to standard adsorption equilibrium and kinetic procedures without further analyses into the adsorbate and adsorbent contact zone. Zn(II), Cu(II) and Mn(II) were chosen study due to their nutritional and toxicological features. Diagnostic methods were used to differentiate the metal behaviour during adsorption and dynamic intraparticle model was further employed to simulate the kinetic conditions. Harkins-Jura isotherm model and pseudo-second kinetic model were determined to fit the adsorption of PTEs on biochar. According to the adsorption efficiency and capacity, PTEs fell into the following sequence: Cu(II) > Mn(II)>Zn(II). It was observed that the kinetics of Cu(II) decreased in the solution by about 1.7 times more than of Zn(II) and about 2.3 times more than of Mn(II). Cu(II) decreased faster and more suddenly than Mn(II) and Zn(II) in the solution on the particle surface and in the solution inside the particle.

Biochar as a filtering media has been attracted increasing attention for applications in urban storm-water runoff (USWR) management. Up-flow percolation tests were conducted with pine bark (PB) and biochars from PB (BCPB) for evaluating changes in dissolved organic carbon (DOC) and total dissolved nitrogen (TDN) concentrations varying with pyrolysis temperatures (i.e., 300, 450, and 700 °C) and types of USWR (i.e., roof and pathway USWR). The most suitable pyrolysis temperature for limiting DOC leaching from BCPB depends on the types of USWR. For all the adopted pyrolysis temperature, BCPB released cumulative amount of DOC up to 0.01% of the TC content in the up-flow percolation tests with pathway USWR. High-temperature (i.e., 700 °C) BCPB released lower cumulative amount of DOC (up to 0.02% of the TC content) compared to the low-temperature (

Environmental, biological, and ecosystem-specific properties may influence the transfer of chemical elements (CEs) from soils to plants, including the variation in the chemical elements’ concentration, their types, and physiological parameters, such as biotransformation ability in the plants. The interface between the soil and a plant, or the concentration of a particular chemical element in a plant with respect to its concentration in the soil, is the basis for a widely used biological absorption coefficient, also known as the transfer factor, bioaccumulation factor, mobility ratio, or plant-soil coefficient, which is expressed in terms of the chemical element’s concentration in the plant and soil. However, from the biogeochemical perspective, these coefficients/factors can provide a comparison of the chemical element (CE) concentration in different media (plants and soil), but only in a particular place (under typical environmental conditions) and at a particular time. However, factors that highlight the variation in the processes, rather than the variation in the chemical element quantity under the conditions of the environmental variation, are required. The second-level or dynamic factors can be used for this purpose. A quantitative method, using the dynamic factors of bioaccumulation, biophilicity, translocation, bioavailability, and phytoremediation, is offered to assess the variation in the process of the uptake of chemical elements by different plants, to evaluate the influence of soil modification on their participation in the plants’ metabolism and to perform quantitative evaluation of phytoremediation efficiency over a particular period of time. The use of dynamic factors for describing the chemical elements’ uptake by plants in various cases, representing aerogenic and edaphic chemical elements’ transfer, is discussed.

This chapter presents the analysis of biodegradable waste from small farms and food industry enterprises, their specific features and prediction of flows’ formation, as well as the amounts to be processed, the possibilities of their use for gas production, and the formation and variation, processing and the prediction of their variation results.

This chapter provides quantitative and qualitative evaluation of biodegradable waste from small farms, food industry enterprises and households in Lithuania that is an example of the EU country with the increasing demand for alternative energy. The potential of the small bioreactors’ use in case of Lithuania and the evaluation of economic, social and environmental effects are provided.

This chapter presents the results of the experimental study of biogas quantity and quality, based on using the mixtures of biodegradable waste such as by-products of margarine production and chicken manure; by-products of margarine production and sludge; wastes of meat and vegetables; meat waste products and sludge; meat waste products and pig manure, as well as meat waste products and pig manure and vegetable and fruit waste products; cow manure and green waste from the garden; fruit and meat waste products; fruit and green waste products; vegetable and green waste products; chicken manure and fruit and green garden waste products; fruit, vegetable and meat waste products and pig manure; and brewer’s spent grains and green garden waste products. A general description of quantitative and qualitative experimental analysis of biogas based on various biodegradable waste products is provided.

This chapter includes a description of biogas production characteristics in the small bioreactors, the composition and major properties of biogas, calculations of the predicted amount of biogas and methane generated, description of the typical charge of bioreactors as well as mathematical modelling of biogas generation kinetics.