A comparison study on the high-rate co-digestion of sewage sludge and food waste using a temperature-phased anaerobic sequencing batch reactor system

Assessing contemporary anaerobic biotechnologies requires proofs on reliable performance in terms of renewable bioenergy recovery such as methane (CH₄) production rate, CH₄ yield while removing volatile solid (VS) effectively. This study, therefore, aims to evaluate temperature-phased anaerobic sequencing batch reactor (TPASBR) system that is a promising approach for the sustainable treatment of organic fraction of municipal solid wastes (OFMSW). TPASBR system is compared with a conventional system, mesophilic two-stage anaerobic sequencing batch reactor system, which differs in operating temperature of 1st-stage. Results demonstrate that TPASBR system can obtain 44% VS removal from co-substrate of sewage sludge and food waste while producing 1.2 m³CH₄/m³_system/d (0.2 m³CH₄/kgVS_added) at organic loading rate of 6.1 gVS/L/d through the synergy of sequencing-batch operation, co-digestion, and temperature-phasing. Consequently, the rapid and balanced anaerobic metabolism at thermophilic stage makes TPASBR system to afford high organic loading rate showing superior performance on OFMSW stabilization.     

Eliminating methanogenic activity in hydrogen reactor to improve biogas production in a two-stage anaerobic digestion process co-digesting municipal food waste and sewage sludge

Laboratory scale two-stage anaerobic digestion process model was operated for 280 days to investigate the feasibility to produce both hydrogen and methane from a mixture feedstock (1:1 (v/v)) of municipal food waste and sewage sludge. The maximum hydrogen and methane yields obtained in the two stages were 0.93 and 9.5 mL/mL feedstock. To eliminate methanogenic activity and obtain substantial hydrogen production in the hydrogen reactor, both feedstock and mixed liquor required treatment. The heat treatment (100 °C, 10 min) for feedstock and a periodical treatment (every 2-5 weeks, either heating, removal of biomass particles or flushing with air) for mixed liquor were effective in different extent. The methane production in the second stage was significantly improved by the hydrogen production in the first stage. The maximum methane production obtained in the period of high hydrogen production was more than 2-fold of that observed in the low hydrogen production period.     

Comparative evaluation of biogas production from dairy manure and co‐digestion with maize silage by CSTR and new anaerobic hybrid reactor

This study aimed to investigate potential methane production through anaerobic digestion of dairy manure and co‐digestion with maize silage. Two different anaerobic reactor configurations (single‐stage continuously stirred tank reactor [CSTR] and hybrid anaerobic digester) were used and biogas production performances for each reactor were compared. The HR was planned to enable phase separation in order to improve process stability and biogas production under higher total solids loadings (≥4%). The systems were tested under six different organic loading rates increased steadily from 1.1 to 5.4 g VS/L.d. The CSTR exhibited lower system stability and biomass conversion efficiency than the HR. The specific biogas production of the hybrid system was between 440 and 320 mL/gVS with 81–65% volatile solids (VS) destruction. The hybrid system provided 116% increase in specific biogas production and VS destruction improved by more than 14%. When MS was co‐digested together with dairy manure, specific biogas production rates increased about 1.2‐fold. Co‐digestion was more beneficial than mono‐material digestion. The hybrid system allowed for generating methane enriched biogas (>75% methane) by enabling phase separation in the reactor. It was observed that acidogenic conditions prevailed in the first two compartments and the following two segments as methanogenic conditions were observed. The pH of the acidogenic part ranged between 4.7 and 5.5 and the methanogenic part was between 6.8 and 7.2.     

Enhanced degradation of phenanthrene in a solid–liquid two‐phase partitioning bioreactor via sonication

The current article examined the feasibility of inducing improved delivery and degradation of phenanthrene in a solid–liquid partitioning bioreactor system at bench scale by means of ultrasonic energy input. Initial degradation rates of phenanthrene by a microbial consortium, delivered from Desmopan, were improved 2.7‐fold in the presence of sonication relative to unsonicated controls. Results demonstrated that an operating window involving on/off sonication cycling improved substrate delivery and rational selection of ultrasound cycling profiles could lead to even further enhancements. Additionally, all results were obtained in a conventional bioreactor with commercial ultrasonic equipment and a commercially available polymer. Subsequent DGGE analysis demonstrated that the sonication cycles selected maintained consortium compositions, relative to control cases, and suggest that exposure would not reduce degradative capabilities under the periods of irradiation examined. Finally, consortium members were identified as belonging to the Pandoraea, Sphingobium, and Pseudoxanthomonas genera. Comparison of genetic sequences in the Ribosomal Database Project revealed that some of the bacterial members, identified at the strain level, had been previously observed in PAH degradations, while others have been reported only in the degradation of other aromatics, such as pesticides. Biotechnol. Bioeng. 2010;105: 997–1001. © 2009 Wiley Periodicals, Inc.     

Rapid determination of trace thiabendazole in apple juice utilizing dispersive liquid–liquid microextraction combined with fluorescence spectrophotometry

Food safety has become a large concern and prompts an urgent need for the development of rapid, simple and sensitive analytical methods that can monitor pesticide residues in foods. This study aimed to provide a method for quantitative determination of trace thiabendazole in apple juice. Due to its high sensitivity and selectivity, fluorescence spectrophotometry was utilized as a front end to dispersive liquid–liquid microextraction (DLLME). The experimental parameters that influenced the extraction were systematically investigated. Under optimum conditions, the whole procedure, including DLLME and analysis of one sample, was carried out within 5 min, and linearity was found in the 5–50 µg/L range with a correlation coefficient (r) of 0.9987. The limit of detection value was 2.2 µg/L. Good reproducibility was achieved based with a less than 4.5% relative standard deviation (RSD) for five replicates at different sample concentrations. This method was shown to be suitable for rapid and sensitive quantification of thiabendazole in apple juice. Copyright © 2015 John Wiley & Sons, Ltd.     

The efficiency of evapotranspiration of landfill leachate in the soil–plant system with willow Salix amygdalina L.

The application of a specific species of willow—Salix amygdalina L., marked by high transpiration ability—is a cheap and effective method of landfill leachate disposal. A 2-year study examined the effectiveness of leachate evapotranspiration from soil–plant systems with willow species S. amygdalina L. Evapotranspiration from soil–plant systems planted with willow was from 1.28 up to 5.12 times higher than evaporation from soil surface barren of vegetation. This proves the usefulness of soil–plant systems with willow in landfill leachate treatment through vaporization. Evapotranspiration efficiency, as opposed to total amount of water added into the lysimeter, was not strong enough to vaporize all input of the landfill leachate in the lysimeters. This may indicate that the ground water requires isolation when soil systems remain under landfill leachate irrigation. Linear dependence between willow biomass growth and transpiration was observed to be significant (p < 0.05). Additionally, the research showed that the application of sewage sludge into the soil caused an increase in vaporization efficiency.     

Modulation of the shape and speed of a chemical wave in an unstirred Belousov–Zhabotinsky reaction by a rotating magnet

The objective of this study was to observe whether a rotating magnetic field (RMF) could change the anomalous chemical wave propagation induced by a moderate‐intensity gradient static magnetic field (SMF) in an unstirred Belousov–Zhabotinsky (BZ) reaction. The application of the SMF (maximum magnetic flux density = 0.22 T, maximum magnetic flux density gradient = 25.5 T/m, and peak magnetic force product (flux density × gradient) = 4 T²/m) accelerated the propagation velocity in a two‐dimensional pattern. Characteristic anomalous patterns of the wavefront shape were generated and the patterns were dependent on the SMF distribution. The deformation and increase in the propagation velocity were diminished by the application of an RMF at a rotation rate of 1 rpm for a few minutes. Numerical simulation by means of the time‐averaged value of the magnetic flux density gradient or the MF gradient force over one rotation partially supported the experimental observations. These considerations suggest that RMF exposure modulates the chemical wave propagation and that the degree of modulation could be, at least in part, dependent on the time‐averaged MF distribution over one rotation. Bioelectromagnetics 34:220–230, 2013. © 2012 Wiley Periodicals, Inc.     

Analysis of fexofenadine in pharmaceutical formulations using tris(1,10‐phenanthroline)–ruthenium(II) peroxydisulphate chemiluminescence system in a multichip device

A simple, rapid and sensitive method has been developed for the analysis of fexofenadine (FEX) in pharmaceutical formulations, using a tris(1,10‐phenanthroline)–ruthenium(II) [Ru(phen)₃²⁺] peroxydisulphate chemiluminescence (CL) system in a multichip device. Various parameters that influence the CL signal intensity were optimized. These included pH, flow rates and concentration of reagents used. Under optimum conditions, a linear calibration curve in the range 0.05–5.0 µg/mL was obtained. The detection limit was found to be 0.001 µg/mL. The procedure was applied to the analysis of FEX in pharmaceutical products and was found to be free from interference from concomitants usually present in these preparations. Copyright © 2011 John Wiley & Sons, Ltd.     

Characterization of the interaction of a mono‐6‐thio‐β‐cyclodextrin‐capped CdTe quantum dots–methylene blue/methylene green system with herring sperm DNA using a spectroscopic approach

Novel, water‐soluble CdTe quantum dots (QDs) capped with β‐cyclodextrin (β‐CD) and ~ 4.0 nm in diameter were synthesized in aqueous solution, and characterized using transmission electron microscopy (TEM). A fluorescence‐sensing system based on the photoinduced electron transfer (PET) of (mono‐6‐thio‐β‐CD)–CdTe QDs was then designed to measure the interaction of phenothiazine dyes [methylene blue (MB) and methylene green (MG)] with herring sperm DNA (hsDNA). This fluorescence‐sensing system was based on a fluorescence “OFF–ON” mode. First, MB/MG adsorbed on the surface of (mono‐6‐thio‐β‐CD)–CdTe QDs effectively quenches the fluorescence of (mono‐6‐thio‐β‐CD)–CdTe QDs through PET. Then, addition of hsDNA restores the fluorescence intensity of (mono‐6‐thio‐β‐CD)–CdTe QDs, because hsDNA can bind with MB/MG and remove it from the as‐prepared (mono‐6‐thio‐β‐CD)–CdTe QDs. In addition, detailed reaction mechanisms of the (mono‐6‐thio‐β‐CD)–CdTe QDs–MB/MG–hsDNA solution system were studied using optical methods, by comparison with the TGA–CdTe QDs–MB/MG–hsDNA solution system. Copyright © 2014 John Wiley & Sons, Ltd.     

Development of a gradient elution high-performance liquid chromatography assay with ultraviolet detection for the determination in plasma of the anticancer peptide [Arg, -Trp, mePhe]-substance P (6–11) (antagonist G), its major metabolites and a C-terminal pyrene-labelled conjugate

[Arg⁶, -Trp^7,9, mePhe⁸]-substance P (6–11), code-named antagonist G, is a novel peptide currently undergoing early clinical trials as an anticancer drug. A sensitive, high efficiency high-performance liquid chromatography (HPLC) method is described for the determination in human plasma of antagonist G and its three major metabolites, deamidated-G (M1), G-minus Met¹¹ (M2) and G[Met¹¹(O)] (M3). Gradient elution was employed using 40 mM ammonium acetate in 0.15% trifluoroacetic acid as buffer A and acetonitrile as solvent B, with a linear gradient increasing from 30 to 100% B over 15 min, together with a microbore analytical column (μBondapak C₁₈, 30 cm×2 mm I.D.). Detection was by UV at 280 nm and the column was maintained at 40°C. Retention times varied by <1% throughout the day and were as follows: G, 13.0 min; M1, 12.2 min; M2, 11.2 min; M3, 10.8 min, and 18.1 min for a pyrene conjugate of G (G–P). The limit of detection on column (LOD) was 2.5 ng for antagonist G, M1–3 and G–P and the limit of quantitation (LOQ) was 20 ng/ml for G and 100 ng/ml for M1–3. Sample clean-up by solid-phase extraction using C₂-bonded 40 μm silica particles (Bond Elut, 1 ml reservoirs) resulted in elimination of interference from plasma constituents. Within-day and between-day precision and accuracy over a broad range of concentrations (100 ng/ml–100 μg/ml) normally varied by <10%, although at the highest concentrations of M1 and M2 studied (50 μg/ml), increased variability and reduced recovery were observed. The new assay will aid in the clinical development of antagonist G.