Comparison of Different Electricity-Based Thermal Pretreatment Methods for Enhanced Bioenergy Production from Municipal Sludge

This paper presents results for a comprehensive study that compares the performance of three electricity-based thermal pretreatment methods for improving the effectiveness of anaerobic digestion (AD) to process municipal wastewater sludge. The study compares thermal pretreatment using conventional heating (CH), microwave (MW), and radio frequency (RF) heating techniques. The effectiveness of the pretreatment methods was assessed in terms of chemical oxygen demand (COD) and biopolymers solubilization, AD bioenergy production, input electrical energy, and overall net energy production of the sequential pretreatment/AD process. The heating applicators for the bench-scale testing consisted of a custom-built pressure-sealed heating vessel for CH experiments, an off-the-shelf programmable MW oven operating at a frequency of 2.45 GHz for MW heating experiments, and a newly developed 1 kW RF heating system operating at a frequency of 13.56 MHz for RF heating experiments. Under identical thermal profiles, all three thermal pretreatment methods achieved similar sludge disintegration in terms of COD and biopolymer solubilization as well as AD bioenergy production (p-value > 0.05). According to the energy assessment results, the application of CH and MW pretreatments resulted in overall negative energy production, while positive net energy production was obtained through the sequential pretreatment/AD process utilizing RF pretreatment.Applied Science, Faculty ofEngineering, School of (Okanagan)ReviewedFacult

Bioenergy production data from anaerobic digestion of thermally hydrolyzed organic fraction of municipal solid waste

The presented dataset in this data article provides quantitative data on the production of bioenergy (biogas and biomethane) from mesophilic batch anaerobic digestion (AD) of thermally hydrolyzed organic fraction of municipal solid waste (OFMSW). The discussion and interpretation of the data are provided in another publication entitled “Hydrothermal Pretreatment of Source Separated Organics for Enhanced Solubilization and Biomethane Recovery” (Razavi et al., 2019). The data and information presented in the current data article include (1) the ratio of soluble to particulate chemical oxygen demand (COD) under different thermal hydrolysis condition, (2) the daily measured biogas and biomethane data, (3) the cumulative methane yield data in terms of mL CH4 produced per gram of volatile suspended solids (VSS) as well as feedstock added, (4) the ultimate methane yield data as well as the relative improvement in methane recovery compared to the control (non-hydrolyzed) digester, (5) the data of first-order organics biodegradation rate constants, (6) the procedure of measuring biogas composition via gas chromatography, (7) the procedure of converting the biogas/methane volume data acquired under the actual experimental condition (mesophilic temperature of 38 °C and atmospheric pressure) to the standard temperature (0 °C) and pressure (1 atm) condition, and (8) the procedure of determining the first-order kinetic rate constants

Degradation of azo dye CI Acid Red 18 using an eco-friendly and continuous electrochemical process

Continuous anodic oxidation of azo dye C.I. Acid Red 18 by using PbO2 electrode in aqueous solution was studied. To reach the best conditions of the process, the influence of various operating parameters such as pH, current density, hydraulic retention time (HRT) and dye concentration on the removal rate of chemical oxygen demand (COD) and color, as indexes showing the amount of efficiency, was investigated. The findings showed that, respectively, 99.9 and 80.0 of the dye and COD were removed (at optimized conditions). Mineralization current efficiency results indicated that at the beginning of the reaction mineralization occurred quickly at a low current density, whereas at high amounts the rate of mineralization the efficiency decreased. At the optimum conditions, the majority of COD was removed only with 38.2 kWh/kg COD of energy consumption in 120 min. By controlling HOaEuro cent/dye concentration ratio via the parameters adjustment, particularly HRT and current density, this system can treat Acid Red 18 well even at high concentrations. Furthermore, the voltammetry study illustrated that electroactive intermediates created during the process were mineralized at current density of 8.6mA/cm(2)