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This work determined the effect of a combination of microwave irradiation and sodium persulfate (Na2S2O8, SPS) on the decomposition of landfill leachate. The effect of treatment temperature, T(60-90°C), SPS concentration, [SPS], (0.05-0.30 M), and solution pH (3.0-8.4) were characterized. As T increased from 60 to 90°C, the observed degradation rate constant of total organic carbon (TOC), kobs, in landfill leachate increased from 0.0032 to 0.0704 min-1. The value kobs fitted the Arrhenius equation and yielded an apparent activation energy of 104 kJ=mol. As [SPS] increased from 0.05 to 0.3 M, kobs increased from 0.0075 to 0.0974 min-1. It decreased as pH increased. Within the design boundaries, T (p < 0.01) significantly affected the TOC removal of landfill leachate but [SPS] did not (p > 0.05). The results demonstrate that microwave-assisted persulfate oxidation can adequately remove organics from landfill leachate. [ABSTRACT FROM AUTHOR]

The research reported in this paper determined the effect of combined microwave irradiation and NaOH pretreatment on solubilization and biodegradation in anaerobic digestion of waste-activated sludge (WAS). Solubilization increased significantly with NaOH concentration (20-60 meqNaOH=L) and microwave final temperature (100-170°C). However, the experimental trials did not adequately approximate the response surface for volatile solids reduction, cumulative biogas production, and biogas yield. Within the design boundaries, the maximum solubilization degree (72%) of WAS occurred at 60 meq=L and 170°C. The highest volatile solids removal efficiency (62.4%) was achieved at 40 meq=L and 170°C. Cumulative biogas production and yield were 2.3-5.7 L=L and 154-393 mL=g added volatile solids, respectively, and both parameters were highest at 20 meq=L and 135°C. [ABSTRACT FROM AUTHOR]

This study evaluates the efficacy of titanium tetrachloride (TiCl4) and titanium sulfate [Ti(SO4)2] on phosphorus (P) removal in synthetic wastewater compared with aluminum sulfate [Al2(SO4)3]. Jar test experiments were performed at various chemical doses and initial pH (pHi) levels to determine the conditions at which P removal was most efficient. The doses with 99% P removal were 0.31 to 0.34 mM for TiCl4, 0.15 mM for Ti(SO4)2, and 0.19 mM for Al2(SO4)3 as Al at 2 mg P/L, 100 mg CaCO3/L, and pHi = 7.0 to 8.0. The optimum pHi was 7 for TiCl4, 5.5 for Ti(SO4)2, and 7 for Al2(SO4)3. The P-removal efficiencies were Ti(SO4)2 > Al2(SO4)3 > TiCl4 at pHi 5.5, and TiCl4 ≈ Al2(SO4)3 > Ti(SO4)2 at pHi 7 and 8.5. P-removal ability of TiCl4 decreased as alkalinity increased. Quadratic models successfully approximated the response surface for P removal efficiency with simultaneous changes in pHi and chemical concentrations [TiCl4 and Al2(SO4)3]. [ABSTRACT FROM AUTHOR]

The effects of the. composition of a mixture containing food waste compost (FWC), rice bran (RB), and oak sawdust (SD) on the antler-type fruiting body (FB) yield of Ganoderma lucidum were studied. Experiments were performed using 0 (control), 5, 10, 15, 20, 25, 30, 35, and 40% (w/w) FWC added to a basal growth medium consisting of 20% (w/w) RB and 80% (w/w) SD. The content of 15% FWC gave the highest FB yield (27.0 ± 1.3 g/bottle), which was 44% higher than the yield (18.6 ± 2.8 g/bottle) of the control treatment. However FWC contents of 20~40% showed reduced yield (2.4~23.0 g/bottle), partly because FWC had a high Na concentration (0.6%). These results demonstrate the potential for use of FWC as a component of a growth medium for production of C. lucidum FBs. [ABSTRACT FROM AUTHOR]

The objectives of this study were to evaluate applicability of food waste compost (FWC) as a substrate for cultivation of Ganoderma lucidum, Lentinula edodes, and Pholiota adipose, and to determine contents of Ca, Mg, Na, and K in fruiting bodies (FB). FB yield per substrate in FWC-free controls was 53 ± 4 g/kg for C. lucidum, 270 ± 90 g/kg for L edodes, and 1,430 ± 355 g/kg for P. adipose. Substrates supplemented with FWC showed the highest FB production at FWC content of 10% for C. lucidum (64 ± 6 g/kg), and 13% for L edodes (665 ± 110 g/kg) and P. adipose (2,345 ± 395 g/kg), which were 1.2-2.5 times higher than the values for the controls. P. adipose contained higher amounts of mineral elements than the other species. Ca, Mg, Na, and K content in FB did not show a significant relation to FWC content. [ABSTRACT FROM AUTHOR]

This research investigated the effect of microwave irradiation (MWI) on cell disintegration in municipal secondary sludge (MSS). A representative MSS Gram-positive bacterium ( Bacillus subtilis) and Gram-negative bacteria ( Acinetobacter calcoaceticus and Pseudomonas aeruginosa) were pure cultured separately and treated using MWI. Compared to untreated controls, MWI significantly increased the soluble chemical oxygen demand (COD) (1.8–4.0-fold), soluble protein concentration (1.1–1.8-fold), and soluble carbohydrate concentration (3.2–14.1-fold), with greater increase in the Gram-negative bacteria. After MSS was MWI-treated with different irradiation times, from 0 to 9 min, soluble COD increased gradually from 0.14 to 2.38 g/L (i.e., 72-fold). Effective disintegration of Gram-negative cell walls and of MSS by MWI was confirmed by scanning electron microscopy. These findings suggest that MWI could be an effective pretreatment method for MSS that is dominated by Gram-negative microorganisms. [ABSTRACT FROM AUTHOR]

For biological nitrification, a set of experiments were carried out to approximate the response of lag period along with ammonia oxidation rate with respect to different concentrations of cyanide (CN−) and ammonia-oxidizing bacteria (AOB), and temperature variation in laboratory-scale batch reactors. The effects of simultaneous changes in these three factors on ammonia oxidation were quantitatively estimated and modeled using response surface analysis. The lag period and the ammonia oxidation rate responded differently to changes in the three factors. The lag period and the ammonia oxidation rate were significantly affected by the CN− and AOB concentrations, while temperature changes only affected the ammonia oxidation rate. The increase of AOB concentration and temperature alleviated the inhibition effect of cyanide on ammonia oxidation. The statistical method used in this study can be extended to estimate the quantitative effects of other environmental factors that can change simultaneously. [ABSTRACT FROM AUTHOR]

The applicability of order-specific primers in minimizing the possible underestimation of microbial diversity was evaluated via denaturing gradient gel electrophoresis (DGGE) analysis of a lab-scale anaerobic digester. Initially, a population analysis with real-time quantitative PCR demonstrated the existence of three methanogenic orders— Methanobacteriales, Methanomicrobiales, and Methanosarcinales—throughout the reaction period. DGGE analyses with three pairs of order-specific primers yielded eight operational taxonomic units (OTUs), whereas DGGE analysis with two independent Archaea-specific primers identified only five. Moreover, the order-specific primers amplified at least one OTU affiliated with each order, whereas no members of Methanobacteriales or Methanomicrobiales were identified with Archaea-specific primers in most samples. These findings provide evidence that order-specific analysis can detect the diversity of methanogens in greater detail than conventional Archaea-specific analysis. [ABSTRACT FROM AUTHOR]