[Comparison of the treatment performance in fresh and mature landfill leachates by Fenton process].

The experiments focused on comparing the removal efficiencies of organic matters in fresh and mature landfill leachate by Fenton treatment. The changes in dissolved organic matter before and after Fenton treatment were assessed using gross organic parameters such as organic compound relative molecular mass (Mr) distribution, chemical oxygen demand (COD), total organic carbon (TOC) and the ratio of COD to TOC. The results from this study demonstrate that high Mr fractions of mature landffill leachate are more easily converted into dissolved small Mr fractions (Mr < 10(3)) by Fenton reaction than those of fresh landfill leachate, since the average Mr of mature landfill leachate is higher than that of fresh landfill leachate and the Mr > 10(5) fraction of the mature leachate account for 64% of the total mass.

Nitroglycerin in the prevention of post-ERCP pancreatitis: a meta-analysis.

The objective of this research paper is to evaluate the effect of prophylactic nitroglycerin in the prevention of post-endoscopic retrograde cholangiopancreatography (ERCP) pancreatitis (PEP) by performing a meta-analysis of randomized controlled trials (RCTs). Electronic databases, including PubMed, EMBASE, the Cochrane library, and the Science Citation Index, were searched to retrieve relevant trials. Outcome measures were the incidence of PEP.

Regulating the hydrolysis of organic wastes by micro-aeration and effluent recirculation.

In this study, the effects of micro-aeration and liquid recirculation on the hydrolysis of vegetable and flower wastes during two-phase solid-liquid anaerobic digestion were assessed. To accomplish this, we evaluated the hydrolysis of five batches of waste that were treated under the following conditions: anaerobic, insufficient micro-aeration (aeration for 5 min every 24 h), and sufficient micro-aeration (aeration for 5 min every 12, 4 and 1h). Hydrolysis was found to depend on the level of micro-aeration.

Co-removal of phthalic acid esters with dissolved organic matter from landfill leachate by coagulation and flocculation process.

The aim of the present study was to evaluate the feasibility of removing phthalic acid esters (PAEs) from fresh and partially stabilized landfill leachates by a coagulation and flocculation (CF) process. This study was focused on the characterization of leachate dissolved organic matter (DOM) and its relationship with PAEs removal, through measures such as: three-dimensional excitation emission matrix fluorescence spectroscopy, UV/Vis absorbance and molecular weight (MW) fractionation of leachate. The results showed that less than 32% of the PAEs in the fresh leachate could be removed with a CF process.

[Effect of operational modes on community structure of type I methanotroph in the cover soil of municipal solid waste landfill].

Type I methanotroph is crucial for methane oxidization and it responses fast to the changes in environment. In this study, 16S rDNA-based denaturing gradient gel electrophoresis (DGGE) gene fingerprint technology was applied to investigate the effect of operational modes, i. e.

[Effects of leachate-loading and irrigation depth on N2O and CO2 emissions from leachate-irrigated soil].

By using prefabricated probe and static chamber, the N2O concentration at different depths along the soil columns irrigated by landfill leachate as well as the N2O and CO2 fluxes were determined. The results showed that leachate irrigation could promote the N2O emission. Within the first 24 hours after irrigation, the N2O fluxes from the soil columns were significantly correlated with the N2O concentrations in the columns at the depths of 10 cm (r = 0.

[Impact of liquid volume of recycled methanogenic effluent on anaerobic hydrolysis].

Methanogenic effluent was recycled to regulate hydrolysis during two-phase anaerobic digestion of organic solid wastes. In order to study the impact of recycled effluent's volume on hydrolysis, four hydrolysis reactors filled with vegetable and flower wastes were constructed, with different liquid volumes of recycled methanogenic effluent, i.e.

Stratification structure of sludge flocs with implications to dewaterability.

Sludge dewatering has proven to be an effective method to reduce the volume of sludge. In this study, a novel stratification approach aimed at better understanding the factors influencing the sludge dewaterability (as determined by capillary suction time, CST) was developed. The sludge flocs from 14 different full-scale wastewater treatment plants (WWTPs), including sewage, leachate, industry, and special-source sludge, were stratified through centrifugation and ultrasound into five layers: (1) supernatant, (2) slime, (3) loosely bound extracellular polymeric substances (LB-EPS), (4) tightly bound EPS (TB-EPS), and (5) pellet.

Estrogenic activity of fractionate landfill leachate.

Dissolved organic matter (DOM) in leachate samples collected at Laogang Sanitary Landfill in Shanghai, China were fractionated using size exclusion chromatography and were characterized using estrogen receptor-alpha competitor screening assay as toxicity activity index. The estrogen activity of leachate was determined mainly by the hydrophobic acid DOM with moderate MW (3000-14,000 Da) and low MW (<630 Da) and with high aromaticity and fluorophores of possibly pyrenyl characteristics. Landfilling for up to seven years or oxic storage for one month degraded a few of these estrogens.

Dissolved organic matter with multi-peak fluorophores in landfill leachate.

Dissolved organic matter (DOM) sampled from municipal landfill leachate of different ages with/without anoxic or aerobic treatment, was intensively fractionated via size exclusion chromatography (SEC) and hydrophobic resins, and was studied with fluorescence excitation and emission matrix (EEM). Six fluorophores with multiple EEM peaks (fluorophore A-F) were identified based on the collected EEM spectra and validated by bi-variate analysis, principal component analysis, and parallel factor analysis, as follows (excitation wavelength Ex and emission wavelength Em): (Ex 240, 310, 360 nm, Em 460 nm), (Ex 220, 280 nm, Em 340 nm), (Ex 220, 270 nm, Em 300 nm), (Ex 220, 280 nm, Em 360 nm), (Ex 230, 320 nm, Em 420 nm) and (Ex 220, 310 nm, Em 400 nm). The spectral characteristics of these fluorophores were discussed using fractional EEM and apparent molecular weight (AMW) data obtained via SEC analysis.

Characterization of water-extractable organic matter during the biostabilization of municipal solid waste.

For the purpose of characterizing the evolution of water-extractable organic matter (WEOM) during the biostabilization of municipal solid waste (MSW) and investigating the correlation between biostability and WEOM characteristics, this study conducted 100-day investigation on biostabilization of MSW and applied various analytical approaches to characterize WEOM. The results showed that the respirometric activity of MSW was reduced by 93% to 10.7 mg kg(-1), and the dissolved organic carbon concentration of WEOM kept steady at around 4.

[Effects of leachate irrigation and cover soil type on N2O emission from municipal solid waste landfill].

By the method of static chamber, the seasonal and diurnal variations of N2O fluxes in two full-scale municipal solid waste (MSW) landfills covered with sandy and clay soils were measured to study the effects of leachate irrigation and cover soil type on the landfill N2O emission. The results showed that the N2O flux in the MSW landfill covered with sandy soil was (242 +/- 576) microg N2O-N x m(-2) x h(-1) in summer, being 3.2 times (P > 0.

[Isothermal studies on liquid-phase adsorption of bisphenol A and dibutyl phthalate by paper].

Adsorption behavior of bisphenol A (BPA) and dibutyl phthalate (DnBP) from aqueous solution onto newsprint was investigated through batch adsorption experiments. Adsorption isothermal data was interpreted by the Freundlich, Langmuir, Dubinin-Radushkevich (D-R), Flory-Huggins (F-H), BET and Temkin equations. In order to determine the best fit isotherm, three error analysis methods were used to evaluate the data: correlation coefficient (R2), residual root mean square error (RMSE) and chi-square test (chi2 test).

Effect of inoculation time on the bio-drying performance of combined hydrolytic-aerobic process.

The study aimed at investigating the effects of inoculation time on the bio-drying performance of combined hydrolytic-aerobic process. Results showed that the addition of inoculating material at different time exhibited various effects not only on the degradation rate of total organics, but also on the performance of water removal and water content reduction. The beginning of aerobic stage (day 5) was suggested to be the optimal time for inoculation.

Minimisation of N2O emissions from a plant-soil system under landfill leachate irrigation.

The irrigation of a plant-soil system with landfill leachate should promote the formation of N2O due to the introduction of organic carbon and mineralized-N and the elevation of the moisture content. Laboratory incubation was performed to minimize N2O emissions from a leachate irrigated plant-soil system by manipulating leachate NH(4)(+)-N loading, moisture content, and soil type. A field investigation, consisting of three plots planted with Cynodon dactylon, Nerium indicum Mill, and Festuca arundinacea Schreb, was then conducted to select plant species.

Toward understanding the mechanism of improving the production of volatile fatty acids from activated sludge at pH 10.0.

A well-defined fractionation approach for sludge flocs was applied to a better understanding of the underlying mechanism of improving the production of volatile fatty acids (VFA) in the hydrolysis and acidification processes at pH 10.0. Specifically, sludge flocs were fractionated through centrifugation and ultrasound into four fractions: (1) slime, (2) loosely bound extracellular polymeric substances (LB-EPS), (3) tightly bound EPS (TB-EPS) and (4) pellet.

Flow analysis of heavy metals in MSW incinerators for investigating contamination of hazardous components.

The contribution of hazardous components in municipal solid waste (MSW) to environmental risks has seldom been quantified due to their heterogeneous streams and irregular disposal patterns. A material flow analysis, in which the input metals in major MSW compositions (excluding discriminable hazardous components) were subtracted from the total output metals in the treatment products, was proposed to estimate the heavy metal contamination in MSW due to hazardous components. The statistical data from 1-year field measurements for two large-scale incinerators in Shanghai city were used as an illustrative example.

Reliable experimental model of hepatic veno-occlusive disease caused by monocrotaline.

Background: Hepatic veno-occlusive disease (HVOD) is a severe complication of chemotherapy before hematopoietic stem cell transplantation and dietary ingestion of pyrrolizidine alkaloids. Many experimental models were established to study its mechanisms or therapy, but few are ideal. This work aimed at evaluating a rat model of HVOD induced by monocrotaline to help advance research into this disease.

Enhancement of anaerobic biodegradability of flower stem wastes with vegetable wastes by co-hydrolysis.

The vegetable wastes and flower stems were co-digested to evaluate the anaerobic hydrolysis performance of difficultly biodegradable organic wastes by introducing readily biodegradable organic wastes. The experiments were carried out in batches. When the vegetable wastes were mixed with the flower stems at the dry weight ratio of 1 to 13, the overall hydrolysis rate increased by 8%, 12%, and 2% according to the carbon, nitrogen, and total solid (TS) conversion rate, respectively.

Minimizing N2O fluxes from full-scale municipal solid waste landfill with properly selected cover soil.

Municipal solid waste landfills emit nitrous oxide (N2O) gas. Assuming that the soil cover is the primary N2O source from landfills, this study tested, during a four-year project, the hypothesis that the proper use of chosen soils with fine texture minimizes N2O emissions. A full-scale sanitary landfill, a full-scale bioreactor landfill and a cell planted with Nerium indicum or Festuca arundinacea Schreb, at the Hangzhou Tianziling landfill in Hangzhou City were the test sites.

Implication of heavy metals distribution for a municipal solid waste management system--a case study in Shanghai.

Heavy metal contamination in municipal solid waste (MSW) is of increasing concern. The occurrence and distribution of heavy metals in MSW and their implications for the integrated MSW management system in mega-cities have been investigated by means of material flow analysis based on a case study of Shanghai in China. A good statistical basis was provided through a one-year monitoring program on the mass and metals composition of the waste from three MSW treatment facilities.

N2O emissions from municipal solid waste landfills with selected infertile cover soils and leachate subsurface irrigation.

This study presents the field investigations into the effects of cover soils and leachate subsurface irrigation on N2O emissions from municipal solid waste landfills. Landfill Site A and Site B, covered with carefully chosen infertile soils, were selected to monitor their diurnal and seasonal variations of N2O emissions. The annual average N2O flux was 469 +/- 796 microg N2O-N m(-2) h(-1) in Site B with leachate subsurface irrigation, three times that of Site A without leachate irrigation.

Bio-drying of municipal solid waste with high water content by aeration procedures regulation and inoculation.

To improve the water content reduction of municipal solid waste with high water content, the operations of supplementing a hydrolytic stage prior to aerobic degradation and inoculating the bio-drying products were conducted. A 'bio-drying index' was used to evaluate the bio-drying performance. For the aerobic processes, the inoculation accelerated organics degradation, enhanced the lignocelluloses degradation rate by 10.

Dissolved organic matter and estrogenic potential of landfill leachate.

The estrogenic potentials of leachate samples collected at Laogang Sanitary Landfill in Shanghai, China were measured together with the associated dissolved organic matter (DOM) in leachate samples. Over 99% of the DOM in fresh leachate was removed upon 3-7 years of landfill, leaving only DOM with strong fluorescent activity. Anoxic or aerobic treatment of landfill leachate can further degrade DOM of MW<300 Da and transform those with fluorescent activity of MW>10(5) Da to those of 2000-10(5) Da.

[Modeling research on impact of pH on metals leaching behavior of air pollution control residues from MSW incinerator].

Metals leaching behavior of air pollution control residues (APC residues) from municipal solid waste incinerator (MSWI) is greatly dependent on the leachate pH. pH-varying leaching tests and Visual MINTEQ modeling were conducted to investigate the mechanism of pH effect on the metals leaching characteristics from MSWI APC residues. Results show that, under acidic environment (for Cd, Zn, and Ni, pH < 8; for Pb, Cu, and Cr, pH < 6; for Al, pH < 4), leaching concentrations of metals increase greatly with the decrease of pH.