1,721,022 research outputs found
A pilot-scale trial comparing mesophilic and thermophilic digestion for the stabilisation of source segregated kitchen waste
No full textSource segregated food waste was collected from domestic properties and its composition determined together with the average weight produced per household, which was 2.91 kg per week. The waste was fed over a trial period lasting 58 weeks to an identical pair of 1.5 m3 anaerobic digesters, one at a mesophilic (36.5 oC) and the other at a thermophilic temperature (56 oC). The digesters were monitored daily for gas production, solids destruction and regularly for digestate characteristics including alkalinity, pH, volatile fatty acid (VFA) and ammonia concentrations. Both digesters showed high VFA and ammonia concentrations but in the mesophilic digester the pH remained stable at around 7.4, buffered by a high alkalinity of 13,000 mg l-1; whereas in the thermophilic digester VFA levels reached 45,000 mg l-1 causing a drop in pH and digester instability. In the mesophilic digester volatile solids (VS) destruction and specific gas yield were favourable, with 67% of the organic solids being converted to biogas at a methane content of 58% giving a biogas yield of 0.63 m3 kg-1 VS added. Digestion under thermophilic conditions showed potentially better VS destruction at 70% VS and a biogas yield of 0.67 m3 kg-1 VS added, but the shifts in alkalinity and the high VFA concentrations required a reduced loading to be applied. The maximum beneficial loading that could be achieved in the mesophilic digester was 4.0 kg VS m-3 d-1
Attenuation of Mecoprop by a low organic carbon landfill liner material: a comparison between batch and column tests
No full textAssessing the potential for attenuation of organic substances within mineral landfill liners
No full textBiodegradation and sorption of toluene and 1,2,4-trichlorobenzene within UK landfilll liners
No full text
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Leachate dissolved organic matter characterization using spectroscopic methods
No full textThis study investigated the use of ultraviolet (UV) and fluorescence spectroscopy to monitor the changes in biodegradability of dissolved organic matter (DOM) in landfill leachates. Experiments to investigate aerobic biodegradation of leachate DOM were carried out using untreated and treated leachate samples collected from two UK municipal solid waste landfills, L1 and L2. Leachate samples collected at different stages of the aerobic treatment processes were characterized by conventional methods (chemical oxygen demand (COD) and dissolved organic carbon content (DOC)) and also by UV spectroscopy and fluorescence excitation-emission matrix. The laboratory-scale aerobic treatment system achieved reductions in COD and DOC in all of the leachates. Results obtained from UV spectrophotometry indicated that the aromatic character of the leachate decreased during aerobic biodegradation. Additionally, the fluorescence intensity of the leachates decreased to various extents, suggesting degradation of humic, fulvic or protein-like structures during biodegradation. Initial results showed strong relations between fluorescent DOC and fluorescent COD and suggest that the strength of these correlations could be a useful tool in distinguishing sources and biodegradability of DOC cheaply and quickly, although further research using different types of leachates is required
- …
