Browsing by Author "Carvalho, L."
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- 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.
- Chemical elements variation in leaves with different development stages of Cistus plants from S. Domingos mine area, South PortugalPublication . Batista, Maria Joao; Gonzalez-Fernandez, Oscar; Abreu, Maria Manuela; Carvalho, L.Soils and leaves of Cistus ladanifer L. and Cistus salviifolius L. in different stages of development (young and mature) were sampled in different sites of the S. Domingos mine. The soils are thin and were developed on heterogeneous materials of metallurgical slags, gossanous materials and weathered host rocks. In general, mature leaves have higher concentrations of As, Cu, Fe, Mn, Pb and Zn than young leaves. Nevertheless, in Moitinhos site the young leaves have higher concentrations of As, Cu and Mn than mature leaves. Near the mining buildings C. ladanifer leaves have higher concentrations of As in mature leaves than C. salviifolius. The Pb concentrations in mature leaves are significantly higher and C. ladanifer contain two fold more than C. salviifolius leaves. Cistus plants show different behaviour on the trace elements uptake and translocation. This knowledge is useful in order to implement remediation programs in mine areas of the Mediterranean region using these pioneer plants.