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Effects of Anaerobic Digestion and Solids Separation on Ammonia Emissions from Stored and Land Applied Dairy Manure Full text
2015
Neerackal, G. M. | Ndegwa, P. M. | Joo, H. S. | Wang, X. | Harrison, J. H. | Heber, A. J. | Ni, J.-Q. | Frear, C.
Field and laboratory studies were conducted to evaluate the effects of anaerobic digestion (AD) and solids-liquid separation on emissions during subsequent storage and land application. The lab storage tests were conducted for 21 days with manure samples obtained at the following four points in a full-scale AD system: raw manure (RM) delivery, raw manure supplemented with other substrates (AD influent), AD effluent, and AD effluent after solids-liquid separation (AD liquid effluent). Ammonia fluxes from stored AD effluent declined from 3.95 to 2.02 g m⁻² day⁻¹. Lower NH₃ fluxes, however, were observed from AD liquid effluent (1.1 g m⁻² day⁻¹) and AD influent (0.25 g m⁻² day⁻¹). Ammonia emissions from full-scale manure storages were similar to those obtained in the lab. Results also indicated significantly lower volatile fatty acid (VFA) in AD effluent and AD liquid effluent compared with that from the AD influent, indicating significant reduction in odor generation potential due to AD and solids-liquid separation processes. Two manure application methods (surface application and manure injection) for both non-AD and AD manures were simulated in the lab and studied for 9 days. Surface-applied non-AD manure exhibited the highest NH₃ flux (0.78 g m⁻² day⁻¹), while injected AD manure led to the lowest NH₃ flux (0.17 g m⁻² day⁻¹). Similar NH₃ emissions results were observed from the field studies. Overall, while AD of dairy manure resulted in significant increases in NH₃ emissions from stored effluent, the AD process significantly reduced NH₃ emissions following application of AD manure on land.
Show more [+] Less [-]Rapid MPN-Qpcr Screening for Pathogens in Air, Soil, Water, and Agricultural Produce Full text
2015
Orlofsky, Ezra | Benami, Maya | Gross, Amit | Dutt, Michelle | Gillor, Osnat
A sensitive, high-throughput, and cost-effective method for screening bacterial pathogens in the environment was developed. A variety of environmental samples, including aerosols, soil of various types (sand, sand/clay mix, and clay), wastewater, and vegetable surface (modeled by tomato), were concomitantly spiked with Salmonella enterica and/or Pseudomonas aeruginosa to determine recovery rates and limits of detection. The various matrices were first enriched with a general pre-enrichment broth in a dilution series and then enumerated by most probable number (MPN) estimation using quantitative PCR for rapid screening of amplicon presence. Soil and aerosols were then tested in non-spiked environmental samples, as these matrices are prone to large experimental variation. Limit of detection in the various soil types was 1–3 colony-forming units (CFU) g⁻¹; on vegetable surface, 5 CFU per tomato; in treated wastewater, 5 CFU L⁻¹; and in aerosols, >300 CFU mL⁻¹. Our method accurately identified S. enterica in non-spiked environmental soil samples within a day, while traditional methods took 4 to 5 days and required sorting through biochemically and morphologically similar species. Likewise, our method successfully identified P. aeruginosa in non-spiked aerosols generated by a domestic wastewater treatment system. The obtained results suggest that the developed method presents a broad approach for the rapid, efficient, and reliable detection of relatively low densities of pathogenic organisms in challenging environmental samples.
Show more [+] Less [-]CO2 Capture on Metallic Oxide Powders Prepared Through Chemical Combustion and Calcination Methods Full text
2015
Granados-Correa, F. | Bonifacio-Martínez, J. | Hernández-Mendoza, H. | Bulbulian, S.
Mg, Zn, Mn, and Al oxide powders have been synthesized through chemical combustion and calcination methods to compare their CO₂ capture performances. The characteristic properties of the adsorbents were evaluated by X-ray diffraction analysis, scanning electron microscopy, and N₂ physisorption measurements. The porous γ-Al₂O₃ prepared through combustion with a BET-specific surface area of 192.1 m²/g, achieving a maximum gas adsorption capacity of 1.71 mmol/g at 60 °C and 1.5 MPa. The MgO adsorbent performed poorly during CO₂ capture, while that Zn and Mn oxides showed no CO₂ adsorption. The results showed theoretical contribution to the field of separation science.
Show more [+] Less [-]Removal of Trace As(V) from Water with the Titanium Dioxide/ACF Composite Electrode Full text
2015
Peng, Liang | Chen, Yaping | Dong, Hong | Zeng, Qingru | Song, Huijuan | Chai, Liyuan | Gu, J.-D.
The novel titanium oxide/active carbon fiber (TiO₂/ACF) electrode was prepared, and electrosorptive properties for As(V) in aqueous solution were investigated. The structure of TiO₂/ACF was characterized with transmission electron microscopy (TEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). Furthermore, the As(V) electrosorptive properties of TiO₂/ACF electrodes with calcination temperature, ionic species, and loaded amount of TiO₂ were measured, and the electrosorption isotherm and kinetics were investigated at the applied voltage of 1.5 V. The optimal load quality of TiO₂ was 0.80 g per ACF electrode (length × width × height = 2 cm × 1 cm × 0.4 cm, 0.30 g), and optimum calcination temperature was 450 °C. The maximum electrosorption capacity of TiO₂/ACF was 8.09 mg/g, about 200 % higher than that of ACF. Moreover, the electrode performance was stable than other materials such as pure ACF, manganese oxide/ACF, and iron oxides/ACF. It can process 100 ppb As(V) of water to 6 ppb (reach the drinking water standards of WHO), demonstrating that our novel electrode is with potential practical application.
Show more [+] Less [-]A Combined Electrocoagulation-Electroperoxidation Process for the Tertiary Treatment of Domestic Wastewaters Full text
2015
Senghor, Fatou | Drogui, Patrick | Seyhi, Brahima
The aim of this study is to develop a process that combines electrocoagulation and electroperoxidation (EC-EP) and to evaluate its performance in treating domestic wastewaters (DWW). Electrolysis was performed using a parallelepipedic electrolytic cell (0.5 L) containing one sacrificial anode (mild steel or aluminum) and one cathode (vitreous carbon). The effects of the treatment time, current density, and type of anode electrode on the process performance were examined. The experimental results revealed that a current density of 4.0 mA cm⁻² was beneficial for DWW treatment. There was a decrease in the chemical oxygen demand (COD), suspended solid (SS), turbidity, color, and total phosphorus (Pₜₒₜ) by 67 ± 9, 98 ± 2, 55 ± 10, 61 ± 9, and 97 ± 0 %, respectively, for a treatment time of 60 min in the electrolysis cell in the presence of mild steel (anode) and vitreous carbon (cathode) electrodes. The process was also determined to be effective for removing pathogens (99 ± 1 % removal), such as fecal coliform (the log-inactivation was higher than 2 units).
Show more [+] Less [-]Removal of Ammonium and 4-Methylphenol from Synthetic Wastewater by Cell-Free Extracts of Nitrifying Sludge Full text
2015
Covarrubias-Vallejo, J. | González-Blanco, G. | Prado-Barragán, A. | Beristain-Cardoso, R.
The feasibility of using cell-free extracts of nitrifying sludge to treat synthetic wastewater containing 4-methylphenol and ammonium was examined. Nitrifying cells were broken by sonication and encapsulated into calcium alginate. Cell-free extracts (CFE) of nitrifying sludge oxidized 4-methylphenol threefold faster than whole-cells, but CFE were not able to oxidize ammonium. The CFE encapsulated into calcium alginate (CFEA) displayed partial nitrification and 4-methylphenol oxidation. Five hours was enough to oxidize 100 % of ammonium and 4-methylphenol, at volumetric rates of 20.80 mg N/L h and 42.86 mg C/L h, respectively. It is inferred that an interaction between the CFE and calcium alginate resulted in the protection of the enzymes.
Show more [+] Less [-]Physiological and Cytological Responses of Deschampsia cespitosa and Populus tremuloides to Soil Metal Contamination Full text
2015
Mehes-Smith, Melanie | Nkongolo, Kabwe K.
Soil metal contamination represents serious threats to plant ecosystem sustainability. Knowledge of metal distribution in plants and the effects of long-term exposure to high levels of metals on cytological stability in Deschampsia cespitosa and Populus tremuloides population is limited. The objective of the present study was to determine how D. cespitosa and P. tremuloides plants cope with soil metal contamination. The effects of high copper (Cu) and nickel (Ni) soil concentrations on cytological stability were also analyzed. The results provide strong evidence that D. cespitosa plants cope with metal contaminations by accumulating them in their root system with limited translocation to their aerial plant parts. Metal bioaccumulation factors were high with values of 5.53 (Cu), 35.19 (Fe), 151.21 (Mg), 24.38 (Ni), and 27.42 (Zn). On the other hand, the bioaccumulation factors in P. tremuloides were 0.42 (Cu), 1.67 (Fe), 4.77 (Mg), 0.94 (Ni), and 5.53 (Zn). The translocation factors (TFs) from roots to leaves for poplar (P. tremuloides) were high for Ni (8.38) and low for Cu (0.71). Cytological analysis clearly showed that long exposure of roots to high levels of metal contamination lead to significant mitotic disruption. Overall, 100 % of the plants from metal-contaminated sites showed a high level of mixoploidy compared to 17 % from the reference sites. Lagging chromosomes in mitotic anaphase were observed in most of the plants from metal-contaminated sites. These mitotic abnormalities appear to have no detectable effects on plant growth and survival.
Show more [+] Less [-]Geostatistical Microscale Study of Magnetic Susceptibility in Soil Profile and Magnetic Indicators of Potential Soil Pollution Full text
2015
Zawadzki, Jarosław | Fabijańczyk, Piotr | Magiera, Tadeusz | Rachwał, Marzena
Directional variograms, along the soil profile, can be useful and precise tool that can be used to increase the precision of the assessment of soil pollution. The detail analysis of spatial variability in the soil profile can be also an important part of the standardization of soil magnetometry as a screening method for an assessment of soil pollution related to the dust deposition. The goal of this study was to investigate the correlation between basic parameters of spatial correlations of magnetic susceptibility in the soil profile, such as a range of correlation and a sill, and selected magnetometric indicators of soil pollution. Magnetic indicators were an area under the curve of magnetic susceptibility versus a depth in the soil profile, values of magnetic susceptibility at depths ranging from 1 to 10 cm, and maximum and background values of magnetic susceptibility in the soil profile. These indicators were previously analyzed in the literature.The results showed that a range of correlation of magnetic susceptibility was significantly correlated with magnetic susceptibility measured at depths 1, 2, and 3 cm. It suggests that a range of correlation is a good measure of pollutants’ dispersion in the soil profile. The sill of the variogram of magnetic susceptibility was found to be significantly correlated with the area under the curve of plot of magnetic susceptibility that is related to the soil pollution. In consequence, the parameters of microscale spatial variability of magnetic susceptibility in s soil profile are important measures that take into consideration the spatial aspect of s soil pollution.
Show more [+] Less [-]Adsorption of Natural Organic Matter onto the Products of Water-Pipe Corrosion Full text
2015
Świetlik, Joanna | Laskowski, Tomasz | Kozyatnyk, Ivan
Natural organic matter (NOM) interaction with corrosion sediments is important because it can adversely affect the behaviour of many organic and inorganic pollutants in drinking water distribution systems. NOM accumulation onto corrosion sediments can cause serious problems for water supply, such as bacteria regrowth and deterioration of water quality. Corrosion sediments have different structures from the well-known iron oxides. The interaction among corrosion sediments and water organic matter can also differ. The main goal of this work was to understand the adsorption mechanism of the processes of NOM interaction with corrosion sediments. Fulvic acid (FA) isotherms on corrosion sediments in logarithmic coordinates of the Freundlich equation have different segments with different slopes, representing the non-adsorbed and adsorbed conditional component of the FA. The formation of structures with a molecular weight higher than the initial FA was observed. FA adsorption on corrosion sediments depends on time. Almost 60–70 % of the FA was removed during the first 10 min of contact. Such rapid adsorption indicates that FA was accumulated onto corrosion sediments mainly due to physical-chemical interaction. The pseudo-second-order kinetics model was demonstrated to better describe the adsorption of FA onto corrosion sediments than the pseudo-first-order model. External mass transfer is the limiting stage of the process of FA adsorption onto corrosion sediments. This knowledge is useful for understanding of corrosion processes and biological regrowth in water supply pipes and thus further decrease of drinking water quality.
Show more [+] Less [-]Odour Samples Degradation During Detention in Tedlar® Bags Full text
2015
Szyłak-Szydłowski, Mirosław
In indirect olfactometry analysis, to avoid condensation or adsorption processes during or storage of the sample, containers made of suitable materials should be used. Also, reaction between the chemicals during transport from the source of the odour to the research laboratory is an important process which can influence on examinations’ results. Study included determination of the odour and compound concentrations of six gas mixtures. Gas samples were collected by silicone hoses into Tedlar® bags and tested by Nasal Ranger, SM-100 olfactometers and Photovac Voyager gas chromatograph. Time of keeping gas in bags was 78 h, and concentration of compounds was measured every hour, eight times per day. For benzene, acetone, 1,1-dichloroethylene, c-1,2-dichloroethylene, t-1,2-dichloroethylene, methyl ethyl ketone and vinyl chloride, 100 % decrease of concentration has been noticed within 78 h of holding in the bag. Average rate of loss of most compounds concentration was from 0.01 to 2.50 % for the first 30 h and from 0.35 to 18.50 % during the last 48 h of examination. Decreasing of odour concentration measured by Nasal Ranger (NR) in all series was between 0.00 and 4.98 % till 30 h, between 1.91 and 100 % in the last 48 h of test and between 1.61 and 100 % in 78 h. In case of odour concentration measured by SM, those values were, respectively, 1.26–4.93 %, 1.39–4.93 % and 2.40–3.18 %. Values of average rate of intensity decreasing were, respectively, 0.77–1.75 %, 2.36–4.67 % and 1.18–2.07 %. Statistically significant correlation coefficients for compound concentrations and intensity, odour concentration obtained by SM-100 as well as NR were, respectively, 0.55–0.97, 0.47–0.99 and 0.37–0.98.
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