Amount Of NH Research Articles

Electrochemical properties of anisotropic nickel hydroxide structures synthesized from nickel ammine complexes

Synthesis of c-axis grown β-Ni(OH)2 was attempted by rapid hydrolysis and/or direct hydrothermal treatment of the mixed solution of NiCl2, HCl and NH3. The UV–vis spectra revealed the addition of NH3 into NiCl2 solution shifted the peak position to shorter wavelength, indicating the formation of nickel ammine complex. Hydrolysis of the mixed solution containing nickel ammine complex gave β-Ni(OH)2 particles. The amount of NH3 in the mixed solution did not affect the crystallinity or morphology of the β-Ni(OH)2 particle by the conventional rapid hydrolysis. Hydrothermal treatment of the hydrolyzed β-Ni(OH)2 particles was changed the morphology from agglomerated particles to nanosheets-linked structure or hexagonal plates. However, any crystal growth or particular-axis growth was not recognized. Then, the direct hydrothermal treatment of the mixed solution was attempted. The direct treatment at certain amount of coexisting NH3 gave small amount of the precipitates, and the precipitates showed distinctive XRD pattern of c-axis grown β-Ni(OH)2. The electrochemical property of the c-axis grown β-Ni(OH)2 structures indicated that the diffusion control was the rate-determining step for the charge/discharge process.

Influence of urea formaldehyde resin on pyrolysis of biomass: a modeling study by TG-FTIR

Pyrolysis is an efficient and recycling way to utilize waste wood-based panels, in which urea-formaldehyde resin (UF) is the main difference between wood-based board and other kinds of biomass. The present paper studied the three main components (cellulose, hemicelluloses, lignin) of poplar wood, in order to effectively and environmentally utilize or dispose of waste wood-based panels with pyrolysis technique, to study the influence of urea formaldehyde resin on pyrolytic characteristic of wood during the process of the pyrolysis of waste wood-based panels, and to in-depth explore the mechanism of the effect of UF on each component of wood. Innovatively, the weight-loss character and gas evolution rule of the model (made from cellulose, xylan and lignin, based on the chemical components stud of poplar wood), the main components as well as the ones mixed with UF were analyzed by TG-FTIR (thermogravimetric analyzer coupled to a Fourier transform infrared spectrometer). Results indicated that UF promoted the generation of water and carboxylic acid substances during the cellulose pyrolysis process. UF combined with lignin, formed some kind of unstable nitrogenous structure which produced a large amount of NH3, which took part in the low-temperature (200-300 degrees C) pyrolysis of lignin, and directly affected the production of pyrolysis products. It can be concluded that during the process of the pyrolysis of waste wood-based panels, lignin was the one that UF mainly impacted among the three main components of wood.

The Properties and Mechanism of CuO Modified Carbon Nanotube for NOx Removal

Carbon nanotube (CNT) supported copper oxide catalysts were prepared, and the morphology and structure of the catalyst were characterized by using scanning electron microscopy, transmission electron microscopy, X-ray diffraction and temperature-programmed desorption experiments. The CuO/CNT catalysts demonstrated high catalytic activities during the selective catalytic reduction (SCR) of NO with NH3 over a temperature range of 150–250 °C. The amount of NH3 adsorbed on the catalyst surface was greater than that of NO or NO + O2 adsorbed on the catalyst surface. These results suggest that the SCR reaction might proceed on the surface of the CuO/CNT catalysts and occur between the adsorbed ammonia and gas phase NO or weakly adsorbed NO. The CuO/CNT catalysts exhibited good stability at low temperatures, which makes them suitable for potential applications in industry.

Preparation and antibacterial activity of magnesium oxide nanoplates via sol–gel process

Magnesium oxide (MgO) nanopowders were synthesised by a sol–gel method with different amounts of ammonium hydroxide (NH3·H2O) and characterised by a combination of thermo gravimetric analysis, X-ray diffraction and transmission electron microscopy. It was found that the structure and morphology of MgO nanopowders can be regulated by the addition of NH3·H2O. When an appropriate amount of NH3·H2O was added into the reaction system, plate-like nanoMgO was obtained. The antibacterial activity of MgO nanoplates was also investigated by the minimum inhibition concentration (MIC) test and bactericidal efficacy against Escherichia coli (E. coli, ATCC 25922). The tested results revealed that the MgO nanoplates have great antibacterial effect with an MIC value of 600 mg/l and the bactericidal rate was about 99.8% at a concentration of 500 mg/l. Furthermore, the effect of NH3·H2O on the structure and morphology of MgO nanopowders and on the growth mechanism are briefly discussed. The hydroxide ion of NH3·H2O, in favour of Mg(OH)2 generation in the precursors, is essential for the formation of MgO nanoplates.

Evaluation of spatial and vertical variability of nitrogen and phosphorus in sewage-irrigated soil in Tongliao, China

The reuse of wastewater for the irrigation of farmlands is gaining popularity, and the nutrient leaching associated with wastewater irrigation is becoming a matter of concern. The variability of nitrogen and phosphorus fractions in wastewater-irrigated soil was investigated in both horizontal and vertical directions in Kongjiaxiang, Tongliao, Inner Mongolia, China. The results showed that wastewater irrigation resulted in the concentrations of available N and P being 40.36% and 66.49% higher, respectively, than those with groundwater irrigation. Different forms of N and P exhibited significantly different distribution patterns. Higher concentrations of NO 3 − and total available N, as well as of those of Ca-P and total available P were observed near wastewater irrigation channels. Ca-P has a spatial distribution pattern similar to that of available P. The concentrations of NO 3 − and NH 4 + were the highest in top soil and decreased with depth. The complex interactions between nitrate leaching and nitrogen transformation processes (e.g., nitrification, denitrification, and mineralization) determined the vertical profile of NO 3 − . The significant amount of NH 4 + loss inhibited its deep seepage. The Ca-bound compound contained more P than other inorganic fractions as a result of high Ca levels throughout the soil profile. The differences in the concentrations of Ca-bound P at different depths could be due to the upward flux or translocation of Ca from subsurface to surface soil and the sequestration of P.

Study on Rural Sanitary Sewage Treatment in Compound Purifying Tank

In the present work, a novel compound purifying tank was adopted in the rural sanitary sewage treatment. The cultivation and acclimation of biological film could be completed in a short start-up by aerobic precoating. According to the running results,the average COD removal rate reached 59.62%,and the removal efficiency of TP was 33.4%.For the denitrogenation,the removal rates were not remarkable (21.7 to NH4+-N,21.9 to TN),but the large removal quantity of NH4+-N and TN were abtained as 8.58mg/L and 9.12mg/L,respectively. The study suggests that the compound purifying tank is a potential alternative for rural sanitary sewage treatment.

Phase- and shape-controlled synthesis of cadmium hydroxyl chloride microstructures via an ammonia-assisted conversion of 1D CdQCl (Q=quinoline) complex microwires

In this paper we reported a NH3·H2O-assisted solvothermal route for successful synthesis of cadmium hydroxyl chlorides (Cdx(OH)yClz) microstructures with different phases and shapes, employing 1D CdQCl (Q=quinoline) complex microwires as the precursor. Experiments contained two processes: firstly, CdQCl complex microwires with 500–600nm in diameter and several hundreds of micrometers in length were prepared by the complexation between CdCl2·2.5H2O and quinoline at room temperature; then, CdQCl microwires were solvothermally treated at 150°C for 10h in the presences of different amounts of NH3·H2O to produce Cdx(OH)yClz microstructures with various phases and shapes. The as-obtained precursor and Cdx(OH)yClz microstructures were characterized by scanning electron microscopy, transmission electron microscopy, Infrared spectrometry and X-ray powder diffraction. Experiments showed that hexagonal Cd(OH)Cl was obtained from water–methanol system, while rhombohedral Cd4(OH)5Cl3 from methanol system. Also, it was found that the shapes of Cdx(OH)yClz could be tuned by the amounts of NH3·H2O. Furthermore, the UV diffuse reflection and photoluminescence spectra of the precursor and Cdx(OH)yClz were also investigated.

Biochemical Processes Controlling Soil Nitrogen Mineralization under Waterlogged Conditions

Changes in precipitation patterns in recent years have resulted in flooding or ponding of many farmlands in the North Central region of the United States. In this work, 11 field‐moist surface soils (0–15 cm) and their air‐dried counterparts were incubated at 30°C under waterlogged conditions for times ranging from 3 to 15 d, and the amounts of NH4–N released were determined. Results showed that, presumably because of slaking effects, the rates of NH4–N release were greater in air‐dried than in field‐moist soils. The mineralization rates of the field‐moist soils were significantly correlated with organic C (r = 0.59, P < 0.05), organic N (r = 0.69, P < 0.05), and microbial biomass C (r = 0.62, P < 0.05) and N (r = 0.63, P < 0.05). The corresponding r values for the air‐dried soils were 0.76 (P < 0.01), 0.87 (P < 0.01), 0.84 (P < 0.01), and 0.85 (P < 0.001), respectively. Estimation of the amounts of N mineralized per hectare of field‐moist soils in 1 d ranged from 2.2 to 4.9 kg (average = 3.3). Those values for air‐dried soils ranged from 5.2 to 26.2 kg (average = 15.5). The rates of hydrolysis of six enzyme substrates studied were significantly correlated with the rates of NH4–N release in the field‐moist soils. The relationships were amidase (r = 0.82, P < 0.01), arginase (r = 0.90, P < 0.001), asparaginase (r = 0.86, P < 0.001), glutaminase (r = 0.88, P < 0.001), β‐glucosidase (r = 0.83, P < 0.01), and β‐glucosaminidase (r = 0.84, P < 0.01). Temperature coefficient (Q10) values ranged from 1.2 to 1.4 (average = 1.3) for the field‐moist soils and from 1.0 to 1.3 (average = 1.1) for their air‐dried counterparts. This study showed that microbial biomass, a number of hydrolases, and slaking seem to play a significant role in hydrolysis of N in temporarily flooded soils.

Phosphorus recovery from artificial wastewater by microbial fuel cell and its effect on power generation

The effects of ammonium (NH4) and magnesium (Mg) on the precipitation of phosphorus in artificial wastewater by an air-cathode single-chamber microbial fuel cell were investigated. When both NH4 and Mg were added to the wastewater, phosphorus was precipitated as struvite. Almost no precipitation occurred with the addition of only NH4, while phosphorus was precipitated as cattiite with the addition of only Mg. However, the amount of precipitate was less than that observed in experiments in which NH4 was also added. As the amounts of NH4 and Mg were increased, more precipitate was observed. Precipitated phosphorus on the cathode was recovered by dissolution in Milli-Q water and MES buffers. It was discovered that the formation of a precipitate reduced the performance of the cathode. Dissolution treatment caused the performance of the cathodes to increase to their initial level.

Surfactant-free sacrificial template synthesis of submicrometer-sized YVO4:Eu3+ hierarchical hollow spheres with tunable textual parameters and luminescent properties

For the first time, well-dispersed submicrometer-sized YVO(4):Eu(3+) hollow spheres were successfully synthesized though a surfactant-free method by employing Y(OH)CO(3):Eu(3+) colloidal spheres as a sacrificial template and NH(4)VO(3) as a vanadium source. The synthetic process mainly consists of two steps, i.e., hydrothermal reaction and acid erosion. By simply changing the amount of NH(4)VO(3) added, the textural parameters of the as-obtained hollow spheres, such as the inner diameter and shell-thickness, can be easily tuned. Moreover, double-shelled hollow spheres could also be obtained when the amount of NH(4)VO(3) was increased to a certain extent. Particularly, the amorphous colloidal spheres of the template could be completely consumed when the amount of NH(4)VO(3) was in large excess, giving rise to the direct formation of uniform hollow spheres without acid erosion. The possible formation process is discussed in detail. Under ultraviolet excitation, the obtained hollow YVO(4):Eu(3+) phosphors showed strong red emissions, and the Commission Internationale d'Eclairage (CIE) coordinates of the YVO(4):Eu(3+) phosphors were closely related with the textural parameters such as the inner diameter, shell-thickness and number of shells, indicating a size-dependent characteristic.

Dinâmica de nutrientes na solução do solo em pomar fertirrigado de citros

O objetivo deste trabalho foi avaliar a dinâmica de nutrientes na solução do solo após a aplicação, via fertirrigação, de nitrogênio, fósforo e potássio a laranjeiras. O experimento foi realizado entre setembro de 2007 e outubro de 2009, em pomares de laranjeiras 'Valência' e 'Hamlin', enxertadas sobre citrumeleiro 'Swingle'. Foram avaliadas cinco doses de N, P2O5 e K2O (0, 25, 50, 100 e 200% da dose recomendada). A solução do solo foi extraída a 30 e 60 cm de profundidade, com o auxílio de extratores com cápsulas porosas. Foram realizadas 11 avaliações durante o período experimental, com as extrações iniciadas após 12 horas das fertirrigações. O aumento das doses reduziu o pH (pH~3,5, na maior dose), e aumentou a condutividade elétrica (CE~1,5 dS m-1, na maior dose) e os teores de NH4, NO3, P, K, Mn e Zn na solução do solo, nas duas profundidades amostradas. Nos meses com maior precipitação pluvial, houve perda potencial de nutrientes por lixiviação, pois maiores concentrações de NO3, K e B foram observadas à profundidade de 60 cm. A análise da solução do solo, obtida por extratores com cápsula de cerâmica porosa, pode ser considerada ferramenta auxiliar para monitorar e avaliar a disponibilidade de nutrientes às plantas.

Comparison of different extract methods on extractable nitrogen in sediments from an urban polluted river

以城市污染河道——南京仙林大学城九乡河表层沉积物为研究对象,探讨沉积物常用提取剂(1 mol/L KCl、2 mol/L KCl、4 mol/L KCl和0.01 mol/L CaCl₂)在不同液土比(5:1、10:1、50:1和100:1)条件下,对城市污染河道沉积物可提取态氮(NH₄⁺-N、NO₃^--N)测定的影响.结果表明:KCl的提取效果要优于CaCl₂,二者NH₄⁺-N提取量分别为312.17~479.23、177.52~339.31 mg/kg,NO₃^--N提取量分别为4.49~21.56、4.25~8.53 mg/kg;可提取态氮提取量随液土比增高而增大,其中1 mol/L KCl组,液土比100:1时NH₄⁺-N和NO₃^--N提取量分别比液土比5:1时增加41.97%和187.08%;NH₄⁺-N提取量随提取剂浓度增高而增大,NO₃^--N随提取剂浓度增高而降低;采用1 mol/L KCl提取剂、液土比100:1的组合联合提取城市污染河道沉积物中的NH₄⁺-N、NO₃^--N,提取效果较好.;To explore the influence of different extractant (1 mol/L KCl, 2 mol/L KCl, 4 mol/L KCl and 0.01 mol/L CaCl₂) and ratio of water to sediment (5:1, 10:1, 50:1 and 100:1) on the determination of extractable nitrogen in sediments from an urban polluted river, surface sediments of Jiuxiang River in Xianlin university town of Nanjing was used in the experiment. Result showed that KCl extract nitrogen more effectively than CaCl₂. The amount of NH₄⁺-N extracted by KCl and CaCl₂ ranged from 312.17 mg/kg to 479.23 mg/kg and 177.52 mg/kg to 339.31 mg/kg, respectively, while NO₃^--N extracted by them ranged from 4.49 mg/kg to 21.56 mg/kg and 4.25 mg/kg to 8.53 mg/kg, respectively. The amount of extractable nitrogen increased with water-sediment ratios. In the experiment group of 1 mol/L KCl, the extract amount of NH₄⁺-N and NO₃^--N increased by 41.97% and 187.08%when the ratio of water to sediment ranged from 5:1 to 100:1, respectively. The amount of NH₄⁺-N extracted increased with higher extractant concentrations, while NO₃^--N decreased with lower ones. The experiment suggested that 1 mol/L KCl as extractant and the water-sediment ratio of 100:1 make a better combination when using for extracting NH₄⁺-N and NO₃^--N from the urban river sediment.

Effects of soil nitrogen and phosphonium on leaf nitrogen and phosphonium stoichiometric characteristics and chlorophyll content of <I>Oligostachyum lubricum</I>

Aims Organ stoichiometric characteristics are the bridge that connects environment and plant organ traits.The relationships among environment,organ stoichiometric characteristics and organ traits reveal mechanisms of environmental effects on plant organ traits and make it possible to regulate plant traits.Our objective was try to find the relationships among soil and leaf nitrogen(N),phosphonium(P) stoichiometric characteristics and leaf chlorophyll content for Oligostachyum lubricum.Methods Total N,P concentrations of the original soil in pots were 421.76 and 37.35 mg.kg –1,respectively,and the original soil was treated as the control(1N1P).Total experimental N,P concentration were two,three and four times as high as the control.Different N,P levels were combined into 10 combinations(2N2P,2N3P,2N4P,3N2P,3N3P,3N4P,4N2P,4N3P,4N4P and 1N1P) and every combination except the control was achieved by adding different amounts of NH 4 NO 3 and NH 4 H 2 PO 4.Leaf samples were collected from ramets of O.lubricum after grown in the pot soil with different N,P level combinations for 45 days.Leaf total N concentration was determined by employing the Kjeldahl method and leaf total P concentration by the acid melt-molybdenum stibium anti-color method.Leaf chlorophyll concentrations were measured based on acetone-ethanol mixture(1 : 1) extraction method.Soil and leaf total N,P concentrations were expressed as mg.kg –1 DW.Important findings Soil total N concentration was significantly positively correlated with leaf total N concentration and leaf N : P ratio,whereas soil total P concentration had no significant correlation with leaf total P concentration and leaf N : P ratio.Leaf N : P ratio increased with the increasing of soil N : P ratio,and the rate of increase of soil N : P ratio was faster than that of leaf N : P ratio.At the same soil condition,leaf N : P ratio of ramets growing in soil with 2N2P and 3N3P had no significant difference,but the both were higher than the control(1N1P) and lower than that growing in soil with 4N4P.Leaf N : P was the main factor that affected leaf chlorophyll content.Results suggested that soil total N concentration had more effect on leaf N,P stoichiometric characteristics than soil total P.Sufficient supply of soil total N lead to the luxury uptake of N by leaves of O.lubricum.The growth of O.lubricum was limited by low soil total N concentration before N and P addition.

Response of Salvinia cucullata to high NH4+ concentrations at laboratory scales

Growth, morphology, NH4+ uptake and mineral allocation in Salvinia cucullata Roxb. ex Bory grown with different amounts of NH4+ were investigated. Plants of uniform size were grown on full strength Smart and Barko medium with different NH4+ concentrations (0.5, 1, 5, 10 and 15mM) and incubated in a greenhouse for four weeks. Salvinia cucullata grew well in the medium with 0.5–1mM NH4+ with a relative growth rate of 0.11–0.12d−1 without exhibiting NH4+ toxicity symptoms. With an NH4+ concentration above 5mM, plant growth was suppressed and signs of NH4+ toxicity were observed. NH4+ toxicity symptoms were obvious in plants supplied with 10mM and 15mM NH4+. These plants had low growth rates, short roots, low numbers of roots and showed chlorosis. Rotted roots and stems were also found in plants fed with 15mM NH4+. This species had a high uptake rate even though the NH4+ concentrations increased, making it an ideal candidate for growth in eutrophic environments. The high NH4+ concentration had a negative effect on K uptake resulting in low K concentration in the plant tissue, but the plants increased N content in plant tissue. Thus, harvested plants can be used as soil fertilizer or for animal feed. Furthermore, maintaining plant biomass can improve the efficiency of water treatment.

Characteristic features of the molecular dynamics and phase transitions of mixed [(NH4)1−xRbx]3H(SO4)2 (x=0, 0.8, and 1) crystals using 1H and 87Rb NMR

Abstract In this study, we grew [(NH4)1−xRbx]3H(SO4)2 (x = 0, 0.8, and 1) mixed crystals using a slow evaporation method and determined their lattice constants by X-ray diffraction. We investigated the molecular dynamics and phase transition temperatures of the crystals using 1H and 87Rb nuclear magnetic resonance (NMR) relaxation and differential scanning calorimetry. When a fraction of rubidium ions in the pure Rb3H(SO4)2 crystal is partial replaced by ammonium ions, we compared the physical properties of the three types of crystals. A small amount of NH 4 + added to Rb3H(SO4)2 led to a change in the physical properties, bringing about a shift in phase transition temperatures and showed a superprotonic phase transition.

EFFECTS OF INORGANIC NITROGEN SOURSE AND NH+4 :NO-3 RATIO ON PROLIFERATION OF DOG ROSE (ROSA CANINA)

Dog rose (Rosa canina) is one of the most important ornamental and medicinal plants which are used as rootstock for ornamental roses as Rosa hybrida and Rosa floribunda. The effects of different concentrations of NH4NO3 (10-15 and 20 mM), KNO3 (15-20 and 25 mM) and NH4:NO3ratios (10:25, 10:30, 10:35, 15:30, 15:35, 15:40, 20:35 and 20:45) was investigated on proliferation stage of dog rose cultivated on Ms media with total nitrogen levels (35; 40, 45, 50, 55, 60 and 65 mM). The relative amounts of NH4+ and NO3- ions influenced the tested parameters. The highest shoot length and most node numbers were obtained with 20:45 NH4+:NO3- ratios. Chlorosis leaf number was less with 15:35 and 20:45 NH4+:NO3- ratios. When NO3- was higher than NH4+, shoot length and node numbers were produced more and chlorosis leaf number was decreased. This study also demonstrates that with increasing nitrogen levels, the growth of shoots and node numbers were more but leaf chlorosis was decreased, therefore proliferation was better. The percentage of axillary shoot was affected by NH4NO3 concentrations and it was highest in 20 mM concentration, but with increasing KNO3, the leaf necrotic and feeble callusing percentage at the cut ends of explants were more and lower in row. Key words: Dog rose, in vitro culture, MS nitrogen source, NH4+: NO3- ratio, proliferation.

Biogeochemistry of terrestrial soils as influenced by short-term flooding

Many terrestrial soils in the US Midwest are temporally flooded during the spring. The effects of short-term flooding on biogeochemical processes that occur in these soils are not fully understood and are the subject of this study. To evaluate these processes we investigated the redox-induced changes in the soil solution for three-cultivated and three-uncultivated/forest soils with different organic matter concentrations. The soils were flooded for 1, 3, 7, and 14-days under anoxic conditions in a biogeochemical reactor. Samples were analyzed for Eh; pH; NO3−; NH4+; total dissolved Mn and Fe; soluble P; dissolved organic and inorganic carbon (DOC–DIC); and evolved CO2. We found strongly contrasting responses of the terrestrial soils to flooding. Reducing conditions were established quickly in the uncultivated and more slowly in the cultivated soils. Concomitant changes in pH were higher for the uncultivated soils. The uncultivated soils showed a higher increase in the amount of NH4+, P, Fe, Mn than the cultivated soils over the 14-day incubation. The total amount of carbon decomposed was much greater for the uncultivated soils with approximately 900 μg C (CO2 + DOC + DIC) decomposed per gram of soil compared to a total decomposition of 240 μg C gsoil−1 for the cultivated soils indicating differences in the type of carbon decomposed. The rapid onset of reducing conditions for the uncultivated soils is attributed to a reactive carbon component that is either absent or occluded in the cultivated soils. This study demonstrates that the biogeochemically-induced changes in carbon dynamics in terrestrial soils are strongly influenced by short-term flooding and the history of soil management.

Strengthening of ultrafine PM aluminium using nano-sized oxycarbonitride dispersoids

► Al compacts processed with powders milled under different amounts of NH 3 were prepared. ► NH 3 is decomposed during milling and N is incorporated into the Al powder. ► Nano-sized N rich dispersoids, formed during sintering, restrain Al grain growth. ► Compact properties follow a linear trend with respect to the amount of N incorporated. ► Controlling NH 3 allows producing ultrafine Al parts with pre-established properties. Composites consisting of ultrafine aluminium, mainly reinforced by in situ nano-sized oxycarbonitride dispersoids, were prepared by mechanical alloying followed by a simple press and sintering method. The mechanical alloying process was performed under atmospheres with different amounts of ammonia. Even when small amounts of ammonia were used, the gas was able to decompose at room temperature, with N incorporated into the aluminium powder. The sintered compact properties were strongly influenced by the amount of N incorporated into the powders during milling, with an almost linear trend for some of these properties.

Desalination of geothermal water by membrane distillation

Membrane distillation process was used for desalination of hot (333 K) geothermal water, which was applied in the plant producing heating water. The investigated water contained 120 g salts/dm3, mainly NaCl. The mineral composition was studied using an ion chromatography method. The obtained rejection of solutes was closed to 100%, but the small amounts of NH3 also diffused through the membrane together with water vapour. However, the composition of obtained distillate allowed to use it as a makeup water in the heating water system. The geothermal water under study was concentrated from 120 to 286 g NaCl/dm3. This increase in the solution concentration caused the permeate flux decline by a 10-20%. The geothermal water contained sulphates, which was subjected to two–fold concentration to achieve the concentration 2.4-2.6 g SO4 2−/dm3 and the sulphates then crystallized in the form of calcium sulphate. As a results, an intensive membranes scaling and the permeate flux decline was observed. The XRD analysis indicated that beside the gypsum also the NaCl crystallites were deposited on the membrane surfaces. The fresh geothermal water dissolved the mixed CaSO4 and NaCl deposit from the membrane surface. This property can be utilized for self-cleaning of MD modules. Using a batch feeding of MD installation, the concentration of geothermal water was carried out over 800 h, without significant performance losses.

Emission of nitrous oxide and carbon dioxide and dynamics of mineral N in wastewater sludge, vermicompost or inorganic fertilizer amended soil at different water contents: A laboratory study

Liming or vermicomposting eliminates pathogens from wastewater sludge, but might affect CO 2 and N 2O emissions when added to soil. Soil incubated at 40%, 60%, 80% and 100% of its water holding capacity (WHC) was amended with limed or unlimed wastewater sludge, vermicompost or inorganic fertilizer, while emissions of N 2O and CO 2 and mineral N concentrations were monitored in aerobic incubation experiment for 7 days. Application of unlimed wastewater sludge significantly increased the emission of CO 2 compared to the unamended soil, but not the other treatments except when unlimed wastewater sludge was added to soil incubated at 60% WHC. The emission of CO 2, was generally largest in soil incubated at 60% WHC and lowest in soil incubated at 100% WHC. The emission of N 2O after 1 day was significantly larger in soil amended with unlimed wastewater sludge compared to the other treatments, but not when soil was incubated at 100% WHC. The emission of N 2O increased with increased soil water content. The concentration of NH 4 + was largest in soil amended with limed or unlimed wastewater sludge and lowest in the unamended soil and soil water content had no clear effect on it. In soil incubated at 40%, 60% and 80% WHC, the largest amount of NO 3 − was found in soil amended with inorganic fertilizer and vermicompost and the lowest in the soil amended with unlimed wastewater sludge. The concentration of NO 3 − in soil decreased when the soil water content increased in all treatments, except in the soil amended with unlimed wastewater sludge. It was found that water content affected the emission of CO 2 of N 2O and the concentration of NO 3 −, but not the amount of NH 4 + and NO 2 − in soil. Application of unlimed wastewater sludge increased the emissions of CO 2 and N 2O and the concentrations of NH 4 +, but decreased the amount of NO 3 − in soil.