Vermicomposting of source-separated human faeces by Eisenia fetida: effect of stocking density on feed consumption rate, growth characteristics and vermicompost production

The main objective of the present study was to determine the optimum stocking density for feed consumption rate, biomass growth and reproduction of earthworm Eisenia fetida as well as determining and characterising vermicompost quantity and product, respectively, during vermicomposting of source-separated human faeces. For this, a number of experiments spanning up to 3 months were conducted using soil and vermicompost as support materials. Stocking density in the range of 0.25-5.00 kg/m² was employed in different tests. The results showed that 0.40-0.45 kg-feed/kg-worm/day was the maximum feed consumption rate by E. fetida in human faeces. The optimum stocking densities were 3.00 kg/m² for bioconversion of human faeces to vermicompost, and 0.50 kg/m² for earthworm biomass growth and reproduction.     

Effect of fresh green waste and green waste compost on mineral nitrogen, nitrous oxide and carbon dioxide from a Vertisol

Incorporation of organic waste amendments to a horticultural soil, prior to expected risk periods, could immobilise mineral N, ultimately reducing nitrogen (N) losses as nitrous oxide (N₂O) and leaching. Two organic waste amendments were selected, a fresh green waste (FGW) and green waste compost (GWC) as they had suitable biochemical attributes to initiate N immobilisation into the microbial biomass and organic N forms. These characteristics include a high C:N ratio (FGW 44:1, GWC 35:1), low total N (<1%), and high lignin content (>14%). Both products were applied at 3 t C/ha to a high N (plus N fertiliser) or low N (no fertiliser addition) Vertisol soil in PVC columns. Cumulative N₂O production over the 28 day incubation from the control soil was 1.5 mg/N₂O/m², and 11 mg/N₂O/m² from the control + N. The N₂O emission decreased with GWC addition (P < 0.05) for the high N soil, reducing cumulative N₂O emissions by 38% by the conclusion of the incubation. Analysis of mineral N concentrations at 7, 14 and 28 days identified that both FGW and GWC induced microbial immobilisation of N in the first 7 days of incubation regardless of whether the soil environment was initially high or low in N; with the FGW immobilising up to 30% of available N. It is likely that the reduced mineral N due to N immobilisation led to a reduced substrate for N₂O production during the first week of the trial, when soil N₂O emissions peaked. An additional finding was that FGW + N did not decrease cumulative N₂O emissions compared to the control + N, potentially due to the fact that it stimulated microbial respiration resulting in anaerobic micro sites in the soil and ultimately N₂O production via denitrification. Therefore, both materials could be used as post harvest amendments in horticulture to minimise N loss through nitrate-N leaching in the risk periods between crop rotations. The mature GWC has potential to reduce N₂O, an important greenhouse gas.     

Production of a refined biooil derived by fast pyrolysis of chicken manure with chemical and physical characteristics close to those of fossil fuels

The chemical and physical properties of raw biooils prevent their direct use in combustion engines. We processed raw pyrolytic biooil derived from chicken manure to yield a colorless refined biooil with diesel qualities. Chemical characterization of the refined biooil involved elemental and several spectroscopic analyses. The physical measurements employed were viscosity, density and heat of combustion. The elemental composition (% wt/wt) of the refined biooil was 82.7 % C, 15.3 % H, 0.2 % N and 1.8 % O, no S. Its viscosity was 0.006 Pa.s and a heat of combustion of 43 MJ kg(-1). The refined biooil fraction contains n-alkanes, ranging from n-C(14) to n-C(27), alkenes varying from C(10:1) to C(22:1), and long-chain alcohols. The refined biooil makes a good diesel fuel due to its chemical and physical properties.     

A sensitive monoclonal antibody-based enzyme-linked immunosorbent assay for chlorpyrifos residue determination in Chinese agricultural samples

A monoclonal antibody-based competitive antibody-coated enzyme-linked immunosorbent assay (ELISA) was developed and optimized for determining chlorpyrifos residue in agricultural products. The IC(50) and IC(10) of this ELISA were 3.3 ng/mL and 0.1 ng/mL respectively. The average recoveries in six agricultural products were between 79.5% and 118.0%, with the intra-assay coefficient of variation being less than 8 %. The limit of detection for all tested products was 30 ng/g. To the best of our knowledge, this assay has the best specificity among all the published research on ELISAs for chlorpyrifos.     

Influence of soluble microbial products (SMP) on wastewater disinfection byproducts: trihalomethanes and haloacetic acid species from the chlorination of SMP

Introduction  

Effluent organic matter from biological wastewater treatment plants is composed of degradation products and soluble microbial products (SMP). Protein, polysaccharide, humic acid, and DNA were major biomolecules of SMP. Little is known about the effects of SMP as microbially derived precursors on disinfection byproduct formation and speciation in biologically treated wastewater. In addition, there has never been any attempt to directly chlorinate the major biomolecules of SMP.     

The endocrine disrupting potential of sediments from the Upper Danube River (Germany) as revealed by in vitro bioassays and chemical analysis

Introduction  

The present study was part of a comprehensive weight-of-evidence approach with the goal of identifying potential causes for the declines in fish populations, which have been observed during the past decades in the Upper Danube River.     

Urban and rural mortality rates during heat waves in Berlin and Brandenburg, Germany

In large cities such as Berlin, human mortality rates increase during intense heat waves. Analysis of relevant data from north-eastern Germany revealed that, during the heat waves that occurred between 1990 and 2006, health risks were higher for older people in both rural and urban areas, but that, during the two main heat waves within that 17-year period of time, the highest mortality rates were from the city of Berlin, and in particular from its most densely built-up districts. Adaptation measures will need to be developed, particularly within urban areas, in order to cope with the expected future intensification of heat waves due to global climate change.     

Comparative performance of flat sheet and spiral wound modules in the nanofiltration of reactive dye solution

Background and purpose

Besides the opportunities for reuse, stringent regulations and growing public awareness demand an enhanced quality of effluent from dye industries. Treatment of an aqueous solution of dye (reactive red 198) was carried out in a nanofiltration unit using both flat sheet and spiral wound modules to obtain a comparative performance evaluation in terms of permeate flux and quality.

Methods

Hydrophilized polyamide membrane with molecular weight cutoff of 150 was used for the experiments. Effects of trans-membrane pressure (TMP), feed concentration and addition of salt on permeate flux were investigated. Percent reduction of color, chemical oxygen demand (COD), total dissolved solid (TDS), and conductivity were determined to assess performance of the membrane.

Results

The maximum flux decline was 16.1% of its initial value at 490 kPa TMP with 50 ppm feed concentration in spiral wound module, whereas the same in flat sheet under same conditions was 7.2%. The effect of TMP showed a quasi-linear increase in flux with increasing pressure. Increased permeate concentration led to the reduction in observed retention of dye in the membrane. The average reduction in color, COD, and TDS were 96.88%, 97.38%, and 89.24%, respectively. The decline in permeate flux was more in case of spiral wound module compared to flat sheet. However, spiral wound module performed better in terms of color removal, COD reduction, and TDS removal.

Conclusion

Substantial removal of color was achieved in the nanofiltration experiments with a marked reduction in COD and TDS. The process allowed the production of permeate stream with great reutilization possibilities.