Evaluating the effect of biochar addition on the anaerobic digestion of swine manure: application of Py-GC/MS

The anaerobic digestion process of swine manure was studied when char was used as supplement for improving performance. The use of pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) was proposed for assessing the organic matter degradation. The assessment on biogas production was carried out using samples of swine manure (SM) supplemented with char in one case and pre-treated by microwave irradiation in the other. This experimental set-up allows for the comparison of the biological degradation observed under these two different configurations and therefore aids in understanding the effect of char particles on the process. Results showed similar performance for both systems, with an average improvement of 39% being obtained in methane production when compared to the single digestion of SM. The analysis of digestate samples by Fourier transform infrared (FTIR) spectroscopy and Py-GC/MS showed improved degradation of proteins, with the Py-GC/MS technique also capable of identifying an increase in microbial-derived material when char was added, therefore highlighting the relevant role of carbon conductive particles on biological systems. Py-GC/MS along with the use of FTIR spectroscopy has proven to be useful tools when evaluating anaerobic digestion

Measurement of biochemical oxygen demand of the leachates

Biochemical oxygen demand (BOD) of the leachates originally from the different types of landfill sites was studied based on the data measured using the two manometric methods. The measurements of BOD using the dilution method were carried out to assess the typical physicochemical and biological characteristics of the leachates together with some other parameters. The linear regression analysis was used to predict rate constants for biochemical reactions and ultimate BOD values of the different leachates. The rate of a biochemical reaction implicated in microbial biodegradation of pollutants depends on the leachate characteristics, mass of contaminant in the leachate, and nature of the leachate. Character of leachate samples for BOD analysis of using the different methods may differ significantly during the experimental period, resulting in different BOD values. This work intends to verify effect of the different dilutions for the manometric method tests on the BOD concentrations of the leachate samples to contribute to the assessment of reaction rate and microbial consumption of oxygen

Analysis of Meso/Thermo AD Process Applied to Pressed Biowaste

Nowadays, anaerobic digestion is a proven technology for the biowaste management. Current research interest is orientated towards process optimization in terms of biogas yield focusing amongst other on mechanical pre-treatment applications to favour solubilisation of biowaste complex organic compounds. A recent mechanical pre-treatment technique involves pressing of segregated biowaste for the physical separation of the material to distinct and more easily handled phases namely semi-liquid and semi-solid biowaste fractions. The aim of the current study is to examine the characteristics of the semi-liquid fraction and to assess the anaerobic digestion process under mesophilic (37 A degrees C) and thermophilic (55 A degrees C) conditions in CSTR pilot scale reactors. The semi-liquid fraction exhibits high biodegradability potential having increased volatile to total solids ratio (0.88) while the low TS content (TS = 188 gTS/kg) facilitates the operating conditions of the process. The mesophilic and thermophilic digestion processes in steady state conditions showed high strength and resilience to the process parameters such as pH, alkalinity, VFA, ammonia and ammonium levels. Mesophilic and thermophilic anaerobic digestion gave an average biogas production of 0.79 and 0.90 m(3)biogas/kgTVS with 66.0 and 68.8 % methane content respectively