The main objectives of this study were to investigate the characteristics of dissolved organic matter (DOM) extracted from the leachate of different treatment process using the chemical and spectroscopic analysing methods. The humic acid (HA), fulvic acid (FA) and hydrophilic (HyI) were isolated and purified by the XAD-8 resin combined with the cation exchange resin method. The analytical results of fluorescence excitation-emission matrix spectroscopy (EEMs) revealed that the fluorescence peaks were protein-like fluorescence for equalization basin and discharge of reverse osmosis (RO), while the fluorescence peaks for second sedimentation tank were humic-like and fulvic-like fluorescence. Moreover, the results also showed that protein-like organic matter are readily removed by biological process and HA and FA can be removed by RO process. Elemental analysis indicated that the nitrogen content in these isolated fractions followed: HA 4HyI 4FA. The information on the characteristics of DOM indicated important role in optimization of leachate treatment processes.

This study evaluated changes in DNA methylation in Arabidopsis thaliana plants grown from seeds implanted with low-energy N(+) and Ar(+) ions. Methylation-sensitive amplified polymorphism (MSAP) testing revealed altered DNA methylation patterns after ion implantation at doses of 1 × 10(14) to 1 × 10(16) ions/cm(2). Comparison of the MSAP electrophoretic profiles revealed nine types of polymorphisms in ion-implanted seedlings relative to control seedlings, among which four represented methylation events, three represented demethylation events, and the methylation status of two was uncertain. The diversity of plant DNA methylation was increased by low-energy ion implantation. At the same time, total genomic DNA methylation levels at CCGG sites were unchanged by ion implantation. Moreover, a comparison of polymorphisms seen in N(+) ion-implanted, Ar(+) ion-implanted, and control DNA demonstrated that the species of incident ion influenced the resulting DNA methylation pattern. Sequencing of eight isolated fragments that showed different changing patterns in implanted plants allowed their mapping onto variable regions on one or more of the five Arabidopsis chromosomes; these segments included protein-coding genes, transposon and repeat DNA sequence. A further sodium bisulfite sequencing of three fragments also displayed alterations in methylation among either different types or doses of incident ions. Possible causes for the changes in methylation are discussed.

No abstract

In this study, two laboratory-scale simulated landfill bioreactors were established, of which Reactor A was operated only with leachate recirculation and served as the control, and Reactor B was operated as semi-aerobic bioreactor landfill with leachate recirculation. In situ leachate treatment and accelerating organic decomposition in semi-aerobic bioreactor landfill was investigated. The results indicated that the introduction of air into the landfill was favourable for optimising the microorganism growth environment and accelerating the degradation o� organic matter. It can be seen clearly �rom the results that NH � +-N can be removed in situ in the semi-aerobic bioreactor landfill with leachate recirculation. Moreover, semi-aerobic bioreactor landfill showed lower emissions for leachate than those in leachate from anaerobic landfill, with low concentrations of COD, VFA, NH � +-N and TKN, and which saved the disposing process o� the discharged leachate. The three-dimensional e�citationemission matrix fluorescence spectroscopy (EEMs) of dissolved organic matter (DOM) in Reactor B changed greatly, and fluorescence peak changed from protein-like fluorescence at Day 60 to humic-like fluorescence at Day 95 and 250, while in Reactor A, fluorescence peak of DOM was always protein-like fluorescence. The comparison of the EEMs indicated that the semi-aerobic landfill accelerated the organic decomposition.