Browsing by Author "Duarte, E."
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- Anaerobic digestion experiment using Cynara Cardunculus L. StalksPublication . Oliveira, I. D. B.; Di Berardino, Santino; Gominho, Jorge; Duarte, E.
- Anaerobic digestion of a fish processing industry sludgePublication . Carvalho, L.; Di Berardino, Santino; Duarte, E.Due to the fact that all fish processing plants operating in Portugal send their sludge from the wastewater treatment process to landfill, and because it is a costly management policy, the aim of this work was to assess the potential use of this substrate for the production of biogas through the anaerobic process technology. Anaerobic digestion has long proven to be an efficient way for the production of a renewable fuel – Biogas - that can be used as a source of energy to produce electricity and heat. This renewable energy resource can be used to reduce the plant processing costs, reducing also the industry carbon footprint. So, the produced sludge becomes a valuable sub-product of the wastewater treatment process instead of being considered a waste, with disposal costs associated. In this study we performed mesophilic (35 ± 1°C) batch assays during 51 days. The inoculum used was from an anaerobic digester operating in a municipal WWTP, also at mesophilic conditions. The anaerobic digestion of the fish sludge produced 700 m3 of CH4/ton SV, which is a really promising result.
- Biogas production from mediterranean crop silagesPublication . Carvalho, L.; Di Berardino, Santino; Duarte, E.Anaerobic digestion has proven to be an efficient way for the production of a renewable fuel. The aim of this work was to study the potential use of two crop silages, yellow lupine (Lupinus luteus L.) and oilseed radish (Raphanus sativus var. oleifera cv. Pegletta), for the production of biogas through the process of anaerobic digestion. The use of yellow lupine was due to its capacity for nitrogen fixation, reducing the fertilization needs for the succeeding crop cycle and reducing also the GHG emissions due to the fertilizer production and its field application. The utilization of the oilseed radish was due to its root exudates with nematicide effect, reducing the needs for soil disinfection, working as a biological weapon and also due to the effect on soil compaction of its large roots, working as a bio-driller. The yellow lupine gave rise to 400 m3 of CH4.t-1 VS and the oilseed radish silage produced approximately 300 m3 of CH4.t-1 VS, proving to be good anaerobic substrates. The inoculum used for the batch digesters was sludge from an anaerobic digester of a WWTP.
- Pre-treatment experiments for the use of Cynara Cardunculus L. as a substrate for the production of biogasPublication . Oliveira, I. D. B.; Lageiro, Manuela; Di Berardino, Santino; Gominho, Jorge; Duarte, E.The purpose of the present study was to explore and evaluate the influence of different pretreatments on Cynara stalks over anaerobic digestion and potential methane production. Different pre-treatments followed by anaerobic digestion batch experiments, were carried-out to Cynara stalks feedstock in order to select the most effective combination. After selecting the most suitable inocullum/substrate (I/S) ratio, different pre-treatments: mechanical, thermal, thermal chemical and enzymatic were studied to enhance the biogas and methane yield in correlation with volatile solids (VS) reduction. The most promising pre-treatment was submitted to a final experiment, in order to set up optimized operational parameters. The thermal chemical pre-treatment applied to the substrate, in the final assay, doubled the cumulative methane yield in comparison with the trial conducted with the untreated one. The methane yield achieved was 0.59 l/g VSadded and 0.31 l/g VSadded for the pre-treated and untreated substrate respectively. The enhancement achieved is also shown in terms of VS reduction. Enzymatic pre-treatment can contibute to an improvement of untreated substrate hydrolyses and also an increase in methane yield of 18% in comparison with the one without enzymatic addition. Mechanical pre-treatment combined with the addition of enzymes enhance hydrolyses of the substrate improving inoculums efficiency however, more experiments are required within higher incubation times.