Population dynamics in bioaugmented membrane bioreactor for treatment of bromoamine acid wastewater.

The performances and microbial population changes in laboratory-scale membrane bioreactor (MBR) augmented with Sphingomonas xenophaga QYY were investigated in the present study. It was demonstrated that after 30 days acclimation, the non-augmented MBR system were able to degrade bromoamine acid (BAA) well. However, the efficiency of the system decreased with BAA concentration increasing. While the augmented MBR showed higher capability, in which the color and COD removal were more than 90% and 50%, respectively. By ribosomal intergenic spacer analysis (RISA), it was found that BAA-utilizing populations gradually increased to become the dominant species in the non-augmented MBR. However, the augmented MBR possessed relatively stable treatment abilities, in which the introduced strain QYY could be persistent and co-exist well with the indigenous populations.

Biocalalyst effects of immobilized anthraquinone on the anaerobic reduction of azo dyes by the salt-tolerant bacteria.

The accelerating effect of dissolved redox mediators has been studied in details in the bio-decolorization processes, but there are little literatures about the non-dissolved redox mediators. Here we describe the accelerating effect of anthraquinone as a redox mediator in the bio-decolorization. Decolorization of azo dyes was carried out experimentally using the salt-tolerant bacteria under immobilized anthraquinone and high salt conditions. Anthraquinone as a redox mediator was able to increase the decolorization rate of azo dyes, and was immobilized by entrapment in calcium alginate (CA), Polyvinyl alcohol (PVA)-H(3)BO(3) and agar, respectively. The effects of various operating conditions such as anthraquinone bead number, dissolved oxygen, temperature and pH on microbial decolorization were investigated experimentally. The reusability of the anthraquinone immobilization beads was evaluated with repeated-batch decolorization experiments. After four repeated experiments, the decolorization rate of CA immobilized anthraquinone retained over 90% of their original value. The experiments explored a great improvement of the redox mediator application and the new bio-treatment concept.

A comparison of the energy availability for chickens of ground and whole grain samples of two wheat varieties.

1. The objective of this study was to examine whether the energy availabilities of two wheat samples, which differed in endosperm hardness, were changed when they were fed ground or as whole grains to chickens. Wheat samples of a variety Haven (hard endosperm) and a variety Riband (soft endosperm), both harvested in 1993 from the same growing site, were used in the experiment. 2. True metabolisable energy (TMEn) was measured in a flock of 24 adult cockerels and the mean of all the samples was 14.68 MJ/kg dry matter (DM). The TMEn of ground wheat was 0.306 MJ/kg DM greater (P < 0.05) than whole grain. There was no significant difference (P > 0.05) in TMEn between the Riband and Haven wheat samples and there were no (P > 0.05) variety x wheat form interactions. 3. The apparent metabolisable energy (AMEn) of the wheat samples was determined with 96 broiler chickens from 19 to 27 d of age. Different amounts of either whole or ground wheat samples were added to a basal diet. Extrapolation of the regression lines indicated AMEn concentrations (MJ/kg DM) of ground Haven 14.33, whole Haven 14.28 ground Riband 14.33 and whole Riband 14.51. There was no evidence (P > 0.05) that whole grain wheat had a different AMEn than ground wheat. 4. A feeding trial used 192 broiler chickens in 48 cages from 24 to 42 d of age. They were fed on a broiler grower diet either mixed with ground wheat before pelleting or with the pelleted grower diet loosely mixed with the whole wheat. There were no differences (P > 0.05) between the 2 wheat varieties or the diet form in growth rates or food conversion ratios. The growth rates of the broilers given a conventional grower and finisher dietary regimen tended (P > 0.05) to be slightly greater than the broilers given the wheat-diluted diets.