169 research outputs found

    Biological treatment of a contaminated gaseous emission from a paint and varnish plant—from laboratory studies to pilot-scale operation

    Get PDF
    A Vapour-Phase Bioreactor (VPB), namely a biotrickling filter, was scaled-up and operated in-situ for the treatment of gaseous emissions from a paint and varnish industrial plant. A microbial culture able to degrade the target compounds was enriched and a laboratory-scale VPB was established in order to evaluate the treatment's performance. The VPB presented removal efficiencies higher than 90% when exposed to Organic Loads (OL) of ca 50 g h−1 m−3 of reactor. The VPB was exposed to dynamic conditions often found in-situ (eg night and weekend shutdown periods) and showed a fast capacity to recover, with and without mineral medium recirculation. After a prolonged interruption period (10 months), the VPB was not able to cope with OL of ca 25 g h−1 m−3 of reactor and re-inoculation was required in order to recover the treatment performance. The VPB also showed limited treatment when exposed to higher OL (ca 500 g h−1 m−3 of reactor). The VPB was then scaled-up and a 3 m3 VPB was operated in-situ, showing removal efficiencies higher than 50% when exposed to an OL of c 5 g h−1 m−3 of reactor, thus complying with current legal demands. The addition of a maintenance feed was shown to be a useful tool for VPB pilot-scale operation when shutdown periods occurred. A factorial design of experiments was carried out, which allowed reduction to one-tenth of the initial supply of the main mineral medium constituents, namely phosphate buffer, ammonium and magnesium salts, and also elimination of the metal supplement. Overall, the VPBs were shown to be robust equipment, being able to respond actively to dynamic treatment scenarios, particularly night and weekend shutdown periods. Copyright © 2003 Society of Chemical Industr

    Enrichment of microbial cultures able to degrade 1,3-dichloro-2 propanol: A comparison between batch and continuous methods

    Get PDF
    Microbial cultures able to degrade xenobiotic compounds are the key element for biological treatment of waste effluents and are obtained from enrichment processes. In this study, two common enrichment methods, suspension batch and immobilized continuous, were compared. The main selection factor was the presence of 1,3-dichloro- 2-propanol (1,3-DCP) as the single carbon source. Both methods have successfully enriched microbial consortia able to degrade 1,3-DCP. When tested in batch culture, the degradation rates of 1,3-DCP by the two consortia were different, with the consortia obtained by batch enrichment presenting slightly higher rates. A preliminary morphological and biochemical analysis of the predominant colonial types present in each degrading consortia revealed the presence of different constituting strains. Three bacterial isolates capable of degrading 1,3-DCP as single strains were obtained from the batch enrichments. These strains were classified by 16S rRNA analysis as belonging to the Rhizobiaceae group. Degradation rates of 1,3-DCP were lower when single species were used, reaching 45 mg l−1 d−1, as compared to 74 mg l−1 d−1 of the consortia enriched on the batch method. Mutualistic interactions may explain the better performance of the enriched consortia

    Efficacy of a preparation of algae interspaced bentonite as a feed additive for all animal species

    Get PDF
    Following a request from the European Commission, the EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP Panel) was asked to deliver a scientific opinion on the efficacy of a preparation of algae interspaced bentonite when used as aflatoxin B1 (AfB1) binder for all animal species; the additive is composed of bentonite feed grade and algae belonging to Ulva spp. The European Commission request follows an opinion of the FEEDAP Panel published in 2016; in that opinion, the FEEDAP Panel could not conclude on the efficacy of the additive. The applicant has submitted additional information to allow the FEEDAP Panel to complete its assessment; these additional data, related to the efficacy of the additive, are the subject of this opinion. In the efficacy study provided, the use of the additive reduced the AfM1 in milk, although this effect seemed to be not consistent over time; this study presented some weaknesses and limitations (incomplete data analysis, reporting and lack of determination of the active substance of the additive in feed) which do not allow the FEEDAP Panel to draw any conclusion on the efficacy of the additive. Due to insufficient evidence, the FEEDAP Panel cannot conclude on the efficacy of the algae interspaced bentonite as a technological feed additive for all animal species

    Chronic wasting disease risk assessment in Portugal: results and future work.

    Get PDF
    Número da Revista Portuguesa de Ciências Veterinárias, dedicado à publicação dos "Proceedings of the 10th Iberian Congress on Prions" que decorreu em Vila Real, Portugal de 19 1 20 de maio de 2022.Chronic wasting disease risk assessment in Portugal: results and future work.This work was supported by the project WastingPrionRisk [POCI-01-0145-FEDER-029947 / PTDC/ CVT-CVT/29947/2017] funded by the Portuguese Foundation for Science and Technology (FCT). FCT PhD grant [SFRH/BD/146961/2019] financed by FCT through FSE (Fundo Social Europeu). This work was also supported by national funds [UIDB/CVT/00772/2020], [LA/P/0059/2020] and [UIDB/04033/2020] by FCT.info:eu-repo/semantics/publishedVersio

    Chronic wasting disease (CWD) risk assessment in Portugal : The genetic approach to study prion protein gene (PRNP) variability in Portuguese populations of three cervid species: red deer, fallow deer and roe deer.

    Get PDF
    Número da Revista Portuguesa de Ciências Veterinárias, dedicado à publicação dos "Proceedings of the 10th Iberian Congress on Prions" que decorreu em Vila Real, Portugal de 19 1 20 de maio de 2022.Among the transmissible spongiform encephalopathies (TSEs), chronic wasting disease (CWD) in cervids is now the rising concern in wildlife within Europe, after the first case was detected in Norway in 2016, in a wild reindeer and until October 2021, a total of 34 cases were described in Norway, Sweden and Finland.This work was supported by the project WastingPrionRisk [POCI-01-0145-FEDER-029947 / PTDC/ CVT-CVT/29947/2017] funded by the Portuguese Foundation for Science and Technology (FCT). FCT PhD grant [SFRH/BD/146961/2019] financed by FCT through FSE (Fundo Social Europeu). This work was also supported by national funds [UIDB/CVT/00772/2020], [LA/P/0059/2020] and [UIDB/04033/2020] by FCT.info:eu-repo/semantics/publishedVersio

    Safety and efficacy of TYFER\u2122 (Ferric tyrosine chelate) as a zootechnical feed additive for chickens, turkeys and minor poultry species for fattening or reared for laying/breeding

    Get PDF
    Following a request from the European Commission, EFSA was asked to deliver a scientific opinion on the safety and efficacy of the product TYFERTM (ferric tyrosine chelate) as zootechnical feed additive for chickens, turkeys and minor poultry species for fattening or reared for laying/breeding. The additive is safe for chickens for fattening at the maximum expected level of 200 mg TYFERTM/kg complete feed; this conclusion can be extended to chickens reared for laying/breeding and extrapolated to turkeys and all minor poultry species for fattening or reared for laying/breeding. No concerns for consumer safety are expected from the use of the additive in poultry nutrition. The EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) considers that the additive poses a risk to users by inhalation, and should also be considered as an irritant to skin, eyes and mucous membranes. Due to the presence of nickel, ferric tyrosine chelate should also be considered as a dermal and respiratory sensitiser. The supplementation of feed with the additive is not expected to pose an environmental risk. TYFERTM used at the minimum recommended level (20 mg/kg feed) in chickens diets has the potential to improve zootechnical parameters of birds. The additive at 20 mg/kg feed has the potential to reduce the caecal load Campylobacter spp. by at least 1 log10-units in chickens for fattening, thus with a potential impact to reduce the risk of human campylobacteriosis; however, the Panel notes that the load of Campylobacter in the chickens caecum is one of the multiple factors that contribute to Campylobacter load in carcases-meat. The conclusions on the efficacy of the additive can be extended to chickens reared for laying/breeding and extrapolated to turkeys and all minor poultry species for fattening or reared for laying/breeding. The Panel recommends including a specification for maximum lithium content in a potential authorisation of the additive

    Safety and efficacy of aluminosilicate of sodium, potassium, calcium and magnesium as a feed additive for pigs

    Get PDF
    Following a request from the European Commission, the Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) was asked to deliver a scientific opinion on aluminosilicate of sodium, potassium, calcium and magnesium as a feed additive for pigs. The additive, that contains at least 66% of aluminosilicate of sodium, potassium, calcium and magnesium as main component, is intended for use as a technological additive (functional groups: (i) anticaking agents) in premixtures and feedingstuffs for pigs at a maximum inclusion level of 30,000 mg/kg. In the absence of data, the FEEDAP Panel could not conclude on the safety of the additive for the target species and the users. The additive is considered safe for the consumer and the environment at the proposed conditions of use. The additive has the potential to act as an anticaking agent in complete feed of pigs at a concentration of 30,000 mg/kg feed
    • …
    corecore