Relative proportions of organic carbon functional groups in biochars as influenced by spectral data collection and processing.

Solid-state 13C Nuclear Magnetic Resonance (NMR) and synchrotron-based X-ray Absorption Near-Edge Structure (XANES) have applications for determining the relative proportions of organic C functional groups in materials. Spectral data obtained by NMR is typically processed using integration (INTEG) whereas XANES spectral data is typically processed using deconvolution (DECONV). The objective of this study was to examine the impact of spectral data collection and processing on the estimated relative proportions of organic C functional groups in biochars. Biochars showed large variations in aromatic C (45-97%), alkyl C (0-23%), O-alkyl C (1-41%), phenolic C (0-20%) and carboxylic C (0-20%). NMR had a better ability than XANES to differentiate % aromatic C across biochars, and the mean % aromatic C was always greater for NMR-INTEG and NMR-DECONV than for XANES-INTEG or XANES-DECONV. NMR-INTEG showed significant associations with NMR-DECONV and XANES-INTEG for % aromatic C and alkyl C, but there were no significant associations between NMR and XANES for % O-alkyl C, phenolic C and carboxylic C. As well, there was no association between NMR-INTEG and XANES-DECONV for any organic C functional group, and in some cases, spectral data collection and processing influenced the quantification of organic C functional groups in a given biochar to the extent that the differences observed were as large as differences observed between biochars when analyzed using the same spectral data collection and processing technique. We conclude that great caution must be taken when comparing studies that determined organic C functional groups in materials using NMR-INTEG versus XANES-DECONV.

Advanced biological sequential treatment of mature landfill leachate using aerobic activated sludge SBR and fungal bioreactor.

This study utilized Penicillium spp. to treat mature landfill leachate (MLL) in a continuous bioreactor and batch experimental tests under non-sterile conditions. MLL characteristics such as chemical oxygen demand (COD), soluble COD (sCOD), total carbon (TC), total organic carbon (TOC), and color removal efficiency were determined. The lignocellulosic enzymatic activity of laccase (Lac), lignin-peroxidase (LiP), and manganese-peroxidase (MnP) was also determined. The batch experimental test was carried out with raw and pretreated MLL containing the initial NH4 +-N concentrations of 0, 105, 352, and 914 mg/L. A maximum COD reduction of 41% and maximum enzymatic activity of 193, 37, and 25 U/L for Lac, LiP and MnP was recorded for the MLL containing 352 mg/L NH4 +-N. The continuous bioreactor exhibited maximum values of 52, 54, 60, 58, and 75 percentage of COD, sCOD, TC, TOC, and color removal efficiency with MLL containing 352 mg/L NH4 +-N that was pretreated at HRT 120 h, while the maximum detected lignocellulosic enzymatic activities were 149, 27, and 16 U/L for Lac, LiP, and MnP, respectively. A total of 64% COD reduction was achieved from the raw MLL considering 12% COD and 100% NH4 +-N reduction in the aerobic activated sludge sequencing batch reactor pretreatment process. The steady and higher removal efficiency of the bioreactor over the entire study period is promising for further exploration to enhance removal of refractory contaminants from the MLL.

Fungal treatment of mature landfill leachate utilizing woodchips and wheat-straw as co-substrates.

Mature landfill leachate (MLL) tend to be highly contaminated due to the presence of refractory contaminants such as humic-fulvic substances, xenobiotic compounds, and heavy metals. This study investigated the treatment efficiency of MLL by deploying Cladosporium sp., Trichoderma asperellum, and Tyromyces chioneus fungal strains. Chemical oxygen demand (COD) and soluble COD (sCOD) removal efficiencies were assessed along with the evaluation of lignocellulosic enzymatic activities of laccase (Lac), lignin-peroxidase (LiP), and manganese-peroxidase (MnP). Glucose, woodchips, and wheat straw were utilized as co-substrates. Higher percentage of COD and sCOD reduction efficiencies and lignocellulosic enzymatic activities were found for woodchips than glucose and wheat-straw. The highest sCOD removal rates were 44%, 38% and 59% by Cladosporium sp., T. asperellum, and T. chioneus, respectively. Overall, Lac activity was significantly higher than LiP and MnP activity for all three species. Tyromyces chioneus was the most effective strain among the three selected fungi in terms of COD and sCOD reduction efficiencies and high enzymatic activities of 165, 14 and 20 U/L were detected for Lac, LiP, and MnP, respectively. Tyromyces chioneus is a potentially effective fungal strain for the enhanced bioremediation of MLL and its further investigation is recommended to explore the removal of recalcitrant contaminants from problematic wastewater.

Statistical modeling of phosphorus solubilization from chemical sludge and evaluation of optimal sodium hydroxide dose.

Phosphorus (P) recovery from sludge has drawn widespread attention across the world to minimize the P load to the watershed, a concern for eutrophication, and to meet the stringent effluent discharge regulations in some countries. Waste activated sludge (WAS) and dewatered sludge (DS) were treated with a wide range of NaOH doses (0-0.75 g g-1 TS). The WAS sludge was diluted to 4.5%-2.25% of TS before the treatment to make comparable amount of TS as of DS (2.25%-1.5%). The kinetic study illustrated that P solubilization reached equilibrium within the first 20 min of treatment duration. Significant positive correlation was found between solution pH and P solubilization, whereas effect of TS was mostly insignificant. The experimental data was well fitted to the exponential models and exhibited maximum P solubilization of about 67% and 56% from the DS and WAS at NaOH doses of 0.71 and 0.27 g g-1 TS, respectively. The optimal NaOH application dose of 0.36 g g-1 TS for DS and 0.20 g g-1 TS for WAS were obtained with 64% and 48% of P solubilization, respectively. The modeling approach and the optimal dose of NaOH illustrated in this study could be utilized for other types of sludges having similar P to TS ratio and P solubilization mechanisms could be further extended to other type of P recovery techniques.

Effect of lignocellulosic enzymes on the treatment of mature landfill leachate.

The inherent necessity to remediate refractory contaminants from the toxic problematic wastewater like mature landfill leachate (MLL) has become a global challenge. This study investigated the effect of a potentially sustainable technological approach, i.e. lignocellulosic enzymatic activities (lignin-peroxidase, manganese-peroxidase and laccase), produced from six selected fungi on the removal efficiency of chemical oxygen demand (COD) and soluble COD (sCOD) from the MLL. The COD/sCOD removal percentage was significantly increased with higher enzymatic activities. Tyromyces chioneus was revealed to be the first ever fungi that produced significant amount of all three enzymes. Penicillium sp. and Tyromyces chioneus were the most effective strains, which removed 66% and 59% of COD, and 64% and 57% of sCOD, respectively. The maximum lignin-peroxidase, manganese-peroxidase and laccase enzymatic activities were 19.3 and 26.9 U/L by Tyromyces chioneus, and 249.8 U/L by Penicillium sp, respectively. It was concluded that lignocellulosic biomass could be a sustainable and advanced biological treatment option to remove refractory components from MLL.

Client satisfaction and risk behaviours of the users of syringe dispensing machines: a pilot study.

INTRODUCTION AND AIMS: The study examines risk behaviours of the users of syringe dispensing machines (SDMs) and evaluates the usefulness of these machines in providing injecting drug users (IDUs) with sterile injecting equipment. DESIGN AND METHODS: Self-administered questionnaires were used among users of SDMs in an Area Health Service of Sydney. RESULTS: The majority of the 167 participants reported being happy with the quality of the SDM services. Problems identified with machines were that they were often broken or jammed (32.8% respondents), not in the right place (21.9%) or require money (16.7%). Just over half (50.9%) of the IDUs use SDMs only from 5 p.m. to 9 a.m., the time when almost all other outlets for accessing sterile injecting equipment remain closed. Relatively young IDUs (age < or = 30 years) were more likely to prefer SDMs over staffed needle syringe programmes (NSPs) compared with older users (age > 30) and to identify stigma (a desire to hide their identity or not liking the way people treat them at staffed NSPs or chemists) as a main reason for using these machines. Primary users of SDMs do not differ from primary users of NSP/chemists in terms of sharing of needles. Those users who had shared in the last month were nearly four times as likely to have never used condoms in sexual encounters over that period (95% confidence interval: 1.2 - 14.5). DISCUSSION AND CONCLUSION: SDMs appear to complement other outlets of NSPs. Providing free-of-cost equipment from SDMs should be considered carefully, as needing money to buy equipment was a reason given for sharing of needles by 35% of those who shared.

The effectiveness and safety of syringe vending machines as a component of needle syringe programmes in community settings.

Syringe vending machines (SVMs) have been introduced in Europe and Australasia as part of the effort to increase the availability of sterile needles and syringes to injecting drug users (IDUs). This qualitative review of 14 published and grey literature studies examines whether community-based SVMs as a component of a comprehensive needle syringe programme (NSP) assist to reduce the spread of HIV and other blood-borne viruses amongst IDUs. The available evidence suggests that SVMs increase access to sterile injecting equipment, reduce needle and syringe sharing, and are likely to be cost efficient. SVMs also complement other modes of NSP delivery as they are used by IDUs who are less likely to attend staffed NSPs or pharmacies. If installed and properly maintained in a well-chosen location and with the local community well prepared, SVMs can enhance the temporal and geographical availability of sterile injecting equipment.