Impact of different structures of biochar on decreasing methane emissions from sewage sludge composting.

Methane (CH) emissions from sewage sludge composting can be reduced by using biochar more effectively. This study investigates the impact of different structure of biochar on CH emissions during sewage sludge composting. Corncob biochar (CB, pore size = 35.

Effect of organic concentration on biological activity and nitrogen removal performance in an anammox biofilm system.

The effects of different concentrations of organic matter on the biological activity and nitrogen removal performance of the anaerobic ammonium oxidation (anammox) system was studied. The results showed that under the conditions of low influent total organic carbon (TOC ≤ 100 mg/L), the activity rate of anammox bacteria was basically unaffected, the anammox bacteria and denitrifying bacteria formed a good synergistic effect, and the maximum total nitrogen (TN) removal efficiency reached 95.77%.

Determination of water content in municipal sludge by multiple headspace extraction gas chromatography.

This paper reports a new method for the determination of sludge water content by a multiple headspace extraction gas chromatographic (MHE-GC) method. It is based on measuring the GC signals for the water vapor in a sample vial from the first five headspace extractions, from which the water content in the sludge sample can be extrapolated according to the established calculation equation. The results show that the method has a good repeatability (the relative standard deviation is less than 1%) and accuracy.

Determination of activity of denitrifying enzyme in soil samples by a headspace gas chromatographic technique.

This paper reported a headspace gas chromatography (HS-GC) for the determination of denitrifying enzyme activity in soil samples. It was based on measuring the NO signal in a set of closed/air-free vials containing soil samples that incubated at the designated conditions. The results showed that the method has a good measurement precision (RSD < 5.

Effect of emerging pollutant fluoxetine on the excess sludge anaerobic digestion.

Fluoxetine (FLX), an emerging pollutant, has been detected in the sewage and excess sludge (ES) at substantial levels. So far, however, the impacts of FLX on the ES anaerobic digestion and the related mechanisms have never been investigated. In this work, the effects of FLX on the ES anaerobic digestion were explored by the batch test under moderate temperature condition.

Municipal solid waste incineration fly ash exposed to carbonation and acid rain corrosion scenarios: Release behavior, environmental risk, and dissolution mechanism of toxic metals.

This study investigated the leaching behavior, environmental risk, and dissolution mechanism of toxic metals (TMs) in solidified/stabilized municipal solid waste incineration fly ash (MSWI FA) exposed to alternative "carbonation + acid rain corrosion" disposal scenarios. The content of TMs (mg/kg) showed a trend of Zn (12,187.10 ± 168.

Determination of total phosphorus in soil and sludge by an effective headspace gas chromatographic method.

This paper reported a novel method for the determination of total phosphorus (TP) content in soil and sludge by a headspace gas chromatography (HS-GC) method. It was based on a reaction between the soluble phosphate in the digestion solution and calcium oxalate solid to form a calcium phosphate precipitate and release oxalate ions, which can react with permanganate to form carbon dioxide, which was then measured by HS-GC. The results showed the complete conversion of phosphate (meanwhile to free oxalate ions in calcium oxalate) in 15 min at 60 °C.

In-situ determination of the observed yield coefficient of aerobic activated sludge by headspace gas chromatography.

This paper describes a headspace gas chromatographic (HS-GC) method for the in-situ determination of the observed yield coefficient (Y) of aerobic activated sludge from domestic wastewater treatment plants. It is based on the measurement of oxygen and carbon dioxide in samples that have been incubated in headspace vials for relatively short periods of time. The method has good precision (the relative standard deviation < 5.

Preparation of cotton-based fibrous adsorbents for the removal of heavy metal ions.

Cotton fiber functionalized with tetraethylenepentamine and chitosan (CTPC) was prepared and used as absorbents for the removal of Cu(II), Pb(II) and Cr(III) ions from aqueous solution. The functionalized materials (CTPC) were characterized by SEM/EDX, FTIR, BET and XRD to confirm the characterization and structural changes of fibers before and after the modifying process. The adsorption performance of CTPC was investigated with different pH, contact time and initial concentration of three kinds of metal ions.

Simple and efficient dual-wavelength spectroscopy for the determination of organic matter in sewage sludge from wastewater treatment.

In this study, a dual-wavelength spectroscopic method for rapid determination of organic matter in sludge was developed. The contents of the organic matter were calculated by determining the consumption of potassium dichromate (KCrO) based on the production of trivalent chromium ions (Cr). Cr could be determined by subtracting the absorption at 800 nm (spectral interference) from the absorption at 650 nm (only contributed by Cr).

[Mechanism of Action of Activated Sludge Properties in Nitrogen Removal by Endogenous Denitrification Through an Intelligent Aeration-controlled A/O Process].

In order to evaluate the mechanism of action of activated sludge properties in nitrogen removal by endogenous denitrification (henceforth EDNR), a new kind of automatic oxygen supply device(AOSD), was applied to the A/O process. The domestication effect of the aeration mode on the activated sludge properties and microbial communities was investigated under the intelligent aeration-controlled A/O process (I-A/O)and the continuous aeration A/O process (C-A/O). The results demonstrated that the effluent NH-N and NO-N components showed obvious accumulation efficiencies and activated sludge generated conspicuous limited bulking in the I-A/O process.

Remediation of chromite ore processing residue by pyrolysis process with sewage sludge.

The present work developed a novel technique to treat chromite ore processing residue (COPR). The process involved mixing the COPR with sewage sludge followed by pyrolysis. The gaseous organic fraction generated during pyrolysis of sludge was beneficial to Cr(VI) reduction.

Factors affecting the sorption of trivalent chromium by zeolite synthesized from coal fly ash.

This research was initiated to determine the effects of different constituents and properties of zeolite synthesized from fly ash (ZFA) on Cr(III) sorption. The uptake of Cr(III) by ZFA was influenced greatly by pH, increasing with the increase in pH. The pH was controlled mainly by calcium-related components (especially CaCO3 and free CaO) and zeolite components in ZFAs.

Changes in chlorinated organic pollutants and heavy metal content of sediments during pyrolysis.

Background: There has been an increasing concern about the treatment and disposal of contaminated sediment from dredged rivers, harbors or estuaries due to the accumulated toxic organics such as dioxins and inorganics, particularly heavy metals like Cr, Pb, Zn, Cu, Hg and Cd. However, considering the huge amount of materials and financial costs involved, any candidate technology must ultimately result in reusable, residual by-products. This can only be made possible if the toxic pollutants are removed or stabilized in the raw sediment and then fed back into the materials cycle.

Removal of PCDD/Fs and PCBS from sediment by oxygen free pyrolysis.

Abstract: Few studies have dealt on the evaluation of volatilization and decomposition reactions of dioxins from sediment by oxygen free pyrolysis. In this study, the performance of pyrolysis on the removal of dioxins from sediment was investigated. Dioxin concentrations of the raw sediment and the solid residues after pyrolysis were analyzed at different conditions.

Removal of phosphate from aqueous solution by zeolite synthesized from fly ash.

Fifteen Chinese fly ashes were converted hydrothermally into zeolites, and phosphate immobilization capacity (PIC) of the synthesized zeolites and the corresponding raw fly ashes were determined using an initial phosphate concentration of 1000 mg/L. Results showed that there was a remarkable increase in PIC (from 1.2 to 7.