136 research outputs found

    Constructed wetland systems vegetated with different plants applied to the treatment of tannery wastewater

    Get PDF
    Wastewaters from leather processing are very complex and lead to water pollution if discharged untreated, especially due to its high organic loading. In this study the survival of different plant species in subsurface horizontal flow constructed wetlands receiving tannery wastewater was investigated. Five pilot units were vegetated with Canna indica, Typha latifolia, Phragmites australis, Stenotaphrum secundatum and Iris pseudacorus, and a sixth unit was left as an unvegetated control. The treatment performance of the systems under two different hydraulic loading rates, 3 and 6 cmd1, was assessed. COD was reduced by 41–73% for an inlet organic loading varying between 332 and 1602 kg ha1 d1 and BOD5 was reduced by 41–58% for an inlet organic loading varying between 218 and 780 kg ha 1 d1. Nutrient removal occurred to lower extents. Phragmites australis and Typha latifolia were the only plants that were able to establish successfully. Despite the high removal of organic content from the influent wastewater, during 17 months of operation, no significant differences in performance were observed between units

    Treatment of industrial wastewater with two-stage constructed wetlands planted with typha latifolia and phragmites australis

    Get PDF
    Industrial wastewater treatment comprises several processes to fulfill the discharge permits or to enable the reuse of wastewater. For tannery wastewater, constructed wetlands (CWs) may be an interesting treatment option. Two-stage series of horizontal subsurface flow CWs with Phragmites australis (UP series) and Typha latifolia (UT series) provided high removal of organics from tannery wastewater, up to 88% of biochemical oxygen demand (BOD5) (from an inlet of 420 to 1000 mg L-1) and 92% of chemical oxygen demand (COD) (from an inlet of 808 to 2449 mg L-1), and of other contaminants, such as nitrogen, operating at hydraulic retention times of 2, 5 and 7 days. No significant (P < 0.05) differences in performance were found between both the series. Overall mass removals of up to 1294 kg COD ha-1 d-1 and 529 kg BOD5 h-1 d-1 were achieved for a loading ranging from 242 to 1925 kg COD ha-1 d-1 and from 126 to 900 kg BOD5 ha-1 d-1. Plants were resilient to the conditions imposed, however P. australis exceeded T. latifolia in terms of propagation.info:eu-repo/semantics/acceptedVersio

    Treatment of tannery wastewater in a constructed wetlands operating in series with different plant species

    Get PDF
    The treatment of tannery wastewater has been a very important issue for pollution control in leather producing countries due to its high pollutant content. Biological processes offer a natural way of treating wastewaters, when compared to more aggressive types of treatment. Constructed wetlands can be an alternative to more conventional biological treatment systems. The species Phragmites australis, Typha spp, Scirpus spp. and Phalaris arundinacea are some of the plants frequently used in subsurface flow constructed wetlands. The present study aimed at assessing the performance of constructed wetland systems operating in series for the treatment of wastewater derived from a tannery plant. Pilot units were operated with horizontal subsurface flow and planted with Typha latifolia and Phragmites australis in an expanded clay matrix. They were subject to two different hydraulic loadings: 180mm/d and 60 mm/d. For an hydraulic loading of 180 mm/d, maximum removal efficiencies of 2100 KgCOD/had (48%) were achieved for unit 1 and 1500 KgCOD/had (33%) for unit 2. For an hydraulic loading of 60 mm/d, maximum removal efficiencies of 360 KgCOD/had (66%) were achieved for unit 1 and of 250 KgCOD/had (60%) for unit 2. No significant differences in performance were found between units with different plant species

    Zinc accumulation in Solanum Nigrum is enhanced by different arbuscular mycorrhizal fungi

    Get PDF
    Solanum nigrum was found to proliferate in sediments with high levels of metal pollution. The effect of Zn on plant growth and tissue metal accumulation was assessed. The response of the plant to the inoculation with four different isolates of arbuscular mycorrhizal fungi (AMF) (Glomus sp. BEG140, Glomus claroideum, Glomus mosseae and Glomus intraradices) was studied. While the isolates of AMF did not have a significant (P < 0.05) influence on mycorrhizal colonisation, increasing Zn concentration to high levels (500 and 1000 mg kg 1) induced significant (P < 0.05) decrease of the AMF colonisation. In general, the presence of AMF did not affect the growth and biomass of S. nigrum individuals. However, the level of metal in the matrix affected S. nigrum growth; plants grown at 100 mg kg 1 had significantly (P < 0.05) lower leaf, stem, root and total biomass than control ones and plants growing at 500 and 1000 mg kg 1 had the significantly (P < 0.05) lowest biomass. Plants inoculated with the AMF G. claroideum and G. intraradices presented significantly (P < 0.05) higher Zn accumulation in all plant tissues. In general, the stem tissues had the higher Zn content while the leaves registered the lowest values, which indicate a high translocation of the metal. AMF inoculation had no significant (P < 0.05) influence on the metal translocation within the plant. This study suggests that inoculation with the AMF G. claroideum or G. intraradices, can enhance the Zn accumulation in the tissues of S. nigrum, not affecting the plant translocation capacities

    Changes in the bacterial community structure in two-stage constructed wetlands with different plants for industrial wastewater treatment

    Get PDF
    This study focused on the diversity of bacterial communities from two series of two-stage constructed wetlands (CWs) treating tannery wastewater, under different hydraulic conditions. Series were separately planted with Typha latifolia and Phragmites australis in expanded clay aggregates and operated for 31 months. The effect of plant species, hydraulic loading and unit stage on bacterial communities was addressed through bacterial enumeration and denaturating gradient gel electrophoresis (DGGE). Diverse and distinct bacterial communities were found in each system unit, which was related in part to the type of plant and stage position (first or second unit in the series). Numerical analysis of DGGE profiles showed high diversity in each unit with an even distribution of species. No clear relation was established between the sample collection time, hydraulic loading applied and the bacterial diversity. Isolates retrieved from plant roots and substrates of CWs were affiliated with c-Proteobacteria, Firmicutes, a-Proteobacteria, Sphingobacteria, Actinobacteria and Bacteroidetes. Both series were effective in removing organic matter from the inlet wastewater, however, based on batch degradation experiments it seems that biodegradation was limited by the recalcitrant properties of the wastewaterinfo:eu-repo/semantics/acceptedVersio

    Solanum nigrum grown in contaminated soil: effect of arbuscular mycorrhizal fungi on zinc accumulation and histolocalisation

    Get PDF
    Zn tissue accumulation in Solanum nigrum grown in a non-contaminated and a naturally contaminated Zn matrix and the effect of inoculation with different arbuscular mycorrhizal fungi (AMF) on metal uptake were assessed. S. nigrum grown in the contaminated soil always presented higher Zn accumulation in the tissues, accumulating up to 1622 mg Zn kg 1. The presence of both Glomus claroideum and Glomus intraradices enhanced the uptake and accumulation of Zn by S. nigrum (up to 83 and 49% higher Zn accumulation, respectively). The main deposits of the metal were found in the intercellular spaces and in the cell walls of the root tissues, as revealed by autometallography, with the inoculation with different AMF species causing no differences in the location of Zn accumulation. These findings indicate that S. nigrum inoculated with selected heavy metal tolerant AMF presents extracting and accumulating capacities, constituting a potentially suitable remediation method for Zn polluted soils.info:eu-repo/semantics/acceptedVersio

    Hard diffractive quarkonium hadroproduction at high energies

    Full text link
    We present a study of heavy quarkonium production in hard diffractive process by the Pomeron exchange for Tevatron and LHC energies. The numerical results are computed using recent experimental determination of the diffractive parton density functions in Pomeron and are corrected by unitarity corrections through gap survival probability factor. We give predictions for single as well as central diffractive ratios. These processes are sensitive to the gluon content of the Pomeron at small Bjorken-x and may be particularly useful in studying the small-x physics. They may also be a good place to test the different available mechanisms for quarkonium production at hadron colliders.Comment: 7 pages, 3 figures, 1 table. Final version to be published in European Physical Journal
    • …
    corecore