Revisiting organic waste-source-dependent molecular-weight governing the characterization within humic acids liking to humic-reducing microorganisms in composting process.

Humic acids (HAs) coupled with humic-reducing microorganisms (HRMs) can facilitate contaminants reduction. Molecular-weight (MW) of HA governs the chemical and HRMs behavior. However, MW of HAs with chemical characteristics linking to HRMs in different wastes composting have never been investigated.

A novel process for food waste recycling: A hydrophobic liquid mulching film preparation.

Appropriate and effective recycling of food waste (FW) has become increasingly significant with the promotion of garbage classification in China. In this study, a novel and green process was developed to recycle FW to prepare a biodegradable composite liquid mulching film (LMF) through crosslinking with sodium alginate (SA). The solid phase of FW was obtained as the raw material after hydrothermal pretreatment to remove pathogens and salts, and to improve the reactivity of active components at a moderate temperature.

Assessing the environmental impact of phenanthrene in different types of land use based on the binding characteristics with dissolved organic matter.

The binding characteristics of phenanthrene with dissolved organic matter (DOM) were studied by the excitation emission matrix fluorescence spectroscopy with parallel factor analysis in four types of land use which derived from forest (F), meadow (M), cropland (C), and greenhouse (G). The results showed that the humification degree and binding characteristics of phenanthrene with DOM were distinct differences in the four soils. The binding capacities of humic-like components with phenanthrene were stronger than those of protein-like components.

[GIS Spatial Distribution and Ecological Risk Assessment of Heavy Metals in Surface Sediments of Shallow Lakes in Jiangsu Province].

To understand pollution of heavy metals in surface sediments of shallow lakes, surface sediments samples of 11 lakes in Jiangsu province were collected to determine the content of six heavy metals including As, Cr, Cu, Pb, Zn and Ni. GIS was used to analyze the spatial distribution of heavy metals, and geological accumulation index (Igeo), modified contamination index (mCd) pollution load index (PLI) and potential ecological risk index (RI) were used to evaluate heavy metal contamination in the sediments. The results showed that: in the lakes' surface sediments, the average content of As, Cu, Zn, Cr, Pb, Ni in multiples of soil background of Jiangsu province were 1.

[Effects of multi-stage strengthening inoculation on bacterial community diversity during composting].

Effects of multi-stage strengthening inoculation on bacterial community diversity were analyzed using PCR-DGGE method in municipal solid waste composting combined with Cluster analysis and changes of Shannon-Weaver index, and the changes of lignocellulose's degradation rate were also detected during the process. The results showed that Multi-stage inoculation of composting can improve the temperature of cooling and the secondary fermentation period. And the hemicellulose, cellulose and lignin degradation rate increased by 7.

[Effect of pH on the fluorescence characteristic of dissolved organic matter in landfill leachate].

Due to its high sensitivity, good selectivity and nondestructivity nature, fluorescence technique is suitable to the study of DOM. In the present study, fluorescence characteristics of dissolved organic matter (DOM) from three different ages of landfill leachate (1a, 5a, 10a) under different pH value were investigated. The fluorescence synchronous scan spectroscopy showed that, in addition to the characteristic each age of landfill leachate owned separately, DOM from three ages of landfill leachate shared some common characteristics with the change in pH as follows: the fluorescence peaks of DOM exhibited in synchronous scan spectroscopy from 1 and 5-year-old leachate showed the maximum fluorescence intensity at pH 5, while that of DOM from 10-year-old landfill leachate appeared at pH 12, and the fluorescence intensity of most fluorescence peaks of DOM from 10-year-old landfill leachate exhibited in synchronous scan spectroscopy at pH 4 ranked second.

[Spectroscopic characterization indicator of landfill in the process of stabilizing].

In the present study, dissolved organic matter (DOM) extracted from landfill of four different ages was studied with fluorescence and ultraviolet-visible spectroscopy in order to explore the possibility of using spectral characteristic changes of DOM as stabilization indicators for landfill. The three-dimensional fluorescence excitation-emission matrix spectroscopy (EEM) displayed that DOM of 0-year-old contained mainly protein-like matter, while DOM extracted from 1, 5 and 10-year-old consisted chiefly of humic matter-like substance, and the intensity change of DOM of 1, 5 and 10-year-old landfill was disordered. Besides, the fluorescence spectroscopy also showed that the r(A,C) value and the fluorescence index f(450/500) of DOM of four different years both decreased with landfill age, which indicated that the low molecular weight fraction of DOM was translated into the high molecular aromatic matter and the degree of humification was enhanced with the time increasing.

[Fluorescence spectroscopic chracterization of the complexation between mercury(II) and dissolved organic matter].

In this study, conventional fluorescence spectroscopy in the excitation, emission and synchronous scan modes and three-dimensional fluorescence spectroscopy in the form of excitation-emission matrix of fluorescence intensity as a function of excitation and emission wavelengths were applied to study the complexation between DOM extracted from landfill leachates and Hg(II) ions. The emission spectrum of DOM exhibited a broad peak with a center at 425 nm and a disorder change of the peak with increasing Hg(II) concentrations, which suggested that the structure of DOM was comparatively simple and the fluorescence character of DOM-Hg(II) complexes resulted from interaction of all fluorescence groups. The excitation spectrum of DOM showed that the intensities of two peaks at 392 and 458 nm both decreased with the addition of Hg(II), indicating that different sources, hydroxy and amido groups, were all involved in the DOM-Hg(II) complexation process.

[Study on fluorescence characteristic of dissolved organic matter from municipal solid waste landfill leachate].

In the present study, the samples of leachate of 0, 5, 10-years-old landfill were respectively taken from landfill plant, the dissolved organic matter (DOM) was extracted from landfill leachate, and the fluorescence spectra of DOM were determined. The fluorescence synchronous scan spectra of DOM in 0-year-old leachate exhibited a primary peak at 335 nm, a secondary peak at 455 nm, and a shoulder peak at 385 nm. While the fluorescence intensities of DOM at different peaks were decreased for 5-year-old leachate, especially those of the peaks at shorter wavelengths (335 and 385 nm) which may be ascribed that the simpler structural components were decreased sharply.

[Study on spectral characteristic of dissolved organic matter fractions extracted from municipal solid waste landfill leachate].

In the present study, the samples of landfill leachate of 0, 5, 10-year-old were respectively taken from landfill plant. Based on a modified Leenheer fractionation scheme, dissolved organic matter (DOM) extracted from landfill leachate of three different ages was fractioned according to their polarities and charge characteristics by using XAD-8 resin, and the fractions of hydrophobic acid (HOA), neutral (HON) and hydrophilic matter (HIM) were obtained, Then the fluorescence and UV spectra of DOM fractions were determined. The fluorescence synchronous scan spectra of DOM fractions exhibited a primary peak at 280 nm for 0-year-old, while the primary peak exhibited at 340nm for 5 and 10 year-old, suggesting that DOM fractions contained mainly protein-like matter at initial stage of landfill, and with the increase in landfill ages, aromatic structures of DOM fractions in leachate were enriched.