Giant Reeds Research Articles

Break oily water emulsion during petroleum enhancing production processes using green approach for the synthesis of SnCuO@FeO nanocomposite from microorganisms.

The aim of this work was to synthesize a green nanoparticle SnCuO@FeO nanocomposite core-shell to break oily water emulsions during petroleum-enhancing production processes as an alternative to chemical and physical processes. In this study, eight bacterial isolates (MHB1-MHB8) have been isolated from tree leaves, giant reeds, and soil samples. The investigation involved testing bacterial isolates for their ability to make FeO nanoparticles and choosing the best producers. The selected isolate (MHB5) was identified by amplification and sequencing of the 16S rRNA gene as Bacillus paramycoides strain OQ878685. MHB5 produced the FeO nanoparticles with the smallest particle size (78.7nm) using DLS. XRD, FTIR, and TEM were used to characterize the biosynthesized nanoparticles. The jar experiment used SnCuO@FeO with different ratios of Sn to CuO (1:1, 2:1, and 3:1) to study the effect of oil concentration, retention time, and temperature. The most effective performance was observed with a 1:1 ratio of Sn to CuO, achieving an 85% separation efficiency at a concentration of 5mg/L, for a duration of 5min, and at a temperature of 373K. Analysis using kinetic models indicates that the adsorption process can be accurately described by both the pseudo-first-order and pseudo-second-order models. This suggests that the adsorption mechanism likely involves a combination of film diffusion and intraparticle diffusion. Regarding the adsorption isotherm, the Langmuir model provides a strong fit for the data, while the D-R model indicates that physical interactions primarily govern the adsorption mechanism. Thermodynamic analysis reveals a ∆H value of 18.62kJ/mol, indicating an exothermic adsorption process. This suggests that the adsorption is a favorable process, as energy is released during the process. Finally, the synthesized green SnCuO@FeO nanocomposite has potential for use in advanced applications in the oil and gas industry to help the industry meet regulatory compliance, lower operation costs, reduce environmental impact, and enhance production efficiency.

First outdoor records in the Old World of the invasive drywood termite, Cryptotermes brevis (Walker, 1853) (Kalotermitidae)

AbstractCryptotermes brevis (Walker, 1853) (Kalotermitidae), commonly called the West Indian drywood termite, is an important structural pest in many parts of the world. Almost all records of C. brevis come from timber or furniture inside human structures. Although originally described for Jamaica, this species appears to be native to the coastal desert area of Peru and Chile, where it commonly occurs outdoors in the dead wood of both living and dead trees in riparian habitats and irrigated agricultural areas. Here, we report outdoor records of C. brevis from an agricultural habitat at the western edge of the Sahara Desert, an area climatically similar to their native range in South America. This constitutes the first outdoor report of the invasive termite in the Old World. In Dakhla, Moroccan Sahara, we found these termites living in the dead wood of a Brazilian peppertree (Schinus terebinthifolia Raddi) and the hollow stems of giant reeds (Arundo donax L.). In North Africa, C. brevis is otherwise known only from structural timbers in northern Egypt. Whether this termite become a significant pest in North Africa remains to be seen.

Production Economical Reinforced Concrete Slabs using Eco-Friendly Material

Concrete is a material that is strong in compression but weak in tension. To overcome this issue, reinforcement must be used to improve the tensile strength of the concrete. However, it is acknowledged that steel has its drawbacks, such as the fact that it has a high cost and corrosion potential, and the rebar is heavy, non-renewable, and non-environmentally friendly. Thus, this experimental study investigates the potential product of economical reinforced concrete slabs using eco-friendly materials. Firstly, to enhance the concrete properties, a compressive, tensile, and flexural test, also a concrete with the addition of polypropylene fiber outlasted the control mix design in terms of strength and durability. The results included the control mix (CM), F1 0.25%, F2 0.50%, F3 0.75%, and F4 1%. The specimen with the highest compression and tensile strength was 24.28 MPa and 3.15 MPa, respectively, for the F1 specimen with 0.25% short fibers. Secondly, the bending test was carried out on ten slabs to check the structural behavior of these slabs reinforced with reed rods as the eco-friendly material. The good results of the bearing capacity of a partially reinforced concrete slab with a reed have been obtained at 23.8 kN. Meanwhile, to obtain better results, this research has enhanced the behavior of the concrete slab by improving the concrete's properties by adding polypropylene synthetic microfiber to the mixed concrete. In addition, giant reeds treated with epoxy increase the bonding strength with concrete, improve tensile strength properties, and reduce the absorption of reeds. Therefore, the bearing capacity results of the reed-reinforced concrete slab became the best, which were 35.83 kN. Thus, reinforcement of one-way slabs by reed partially with appropriate diameters could be substituted to obtain good performance in the reconstruction of low-cost buildings. As a result, economical reinforced concrete slabs have been produced using eco-friendly materials. Doi: 10.28991/CEJ-2023-09-06-010 Full Text: PDF

New highlights on Old World giant Phragmites (Poaceae) using leaf and floral bract microscopic characters

The genus Phragmites includes taxa that are very difficult to distinguish macroscopically, and even genetically. To better discriminate these taxa, microscopic traits, such as the epidermis of floral bracts and leaves, and leaf anatomy, were investigated. In the Old World, four distinct giant reeds species (> 3 m) were delineated: two tropical species, P. karka and P. mauritianus, and two Mediterranean species, P. altissimus and P. frutescens. Previously included within P. australis sensu lato, the rehabilitation of P. altissimus and P. frutescens is supported by relevant distinctive characteristics. Conversely, the small reeds (< 3 m) from temperate to cold regions form a distinct group. Although this group is still difficult to subdivide with epidermis traits, three taxa can be separated using leaf anatomy: both the Afro-European and the Australian-E. Asian P. australis sensu stricto, and P. japonicus. Using iodine green solution, we link our morphological analyses with previous genetic clustering, the green coloration of floral bracts and margin leaf teeth matches with the presence of nuclear waxy gene bands in P. frutescens and P. mauritianus (100 bp), and P. altissimus (200 bp), while P. karka, P. australis subsp. australis and P. japonicus have no coloration nor waxy band. While leaf anatomy features seem to be correlated with eco-climatic conditions, the epidermal traits delimited other clades. For leaf epidermis P. karka, P. mauritianus, and P. frutescens present the more ancestral characters, whereas P. australis, P. japonicus, and P. altissimus possess derived traits. Lastly, floral bract epidermis traits separate two divergent evolutionary lineages from the basal P. karka.

Hydrogen Production from Enzymatic Hydrolysates of Alkali Pre-Treated Giant Reed (Arundo donax L.)

The perennial rhizomatous grass giant reed (Arundo donax L.) can be exploited to produce hydrogen by dark fermentation. This implies a high availability of simple sugars, like glucose and xylose, and, thus, a pre-treatment is necessary to remove lignin and expose the holocellulose to enzymatic attack. This study aimed at evaluating the hydrogen production from giant reed hydrolysates. Giant reed dry meal was pre-treated with diluted NaOH (1.2% weight/weight), then the solid fraction was separated from the alkaline black liquor by filtration, enzymatically hydrolyzed with a cellulase blend (Cellic CTec2), and fermented in mesophilic batch conditions with a microbial consortium derived from pig slurry. The impact on hydrogen yield of initial pH was evaluated by comparing the hydrogen production from hydrolysates with not adjusted (5.3) or adjusted initial pH (8.7) using NaOH or alkaline black liquor. The highest hydrogen yield, 2.0 mol/mol of hexoses, was obtained with alkaline initial pH 8.7, regardless of how the pH adjustment was managed. The yield was 39% higher than that obtained in reactors with initial pH 5.3. In conclusion, thermo-alkaline pre-treatment followed by enzymatic saccharification and initial pH adjustment at 8.7 with the black liquor remaining after pre-treatment is a promising strategy to produce hydrogen from giant reeds in dark fermentation.

Advanced Biomethane Production from Biologically Pretreated Giant Reed under Different Harvest Times

Increasing energy demands and fossil fuel consumption causing global warming has motivated research to find alternative energy sources such as biofuels. Giant reed (Arundo donax L.), a lignocellulosic, perennial, rhizomatous grass has been proposed as an important bioenergy crop for advanced biofuel in the Mediterranean area. Anaerobic digestion for advanced biomethane seems to be a promising approach. However, the presence of lignin in lignocellulosic biomass represents the main obstacle to its production (due to its recalcitrance). Thus, to use effectively lignocellulosic biomass in anaerobic digestion, one or more pretreatment steps are needed to aid microorganisms access to the plant cell wall. To this end, the present study investigated the effect of fungal pretreatment of giant reeds obtained from two different harvesting time (autumn and winter) on biomethane production by anaerobic digestion using two white rot fungi (Pleurotus ostreatus and Irpex lactus, respectively). The highest biomass lignin degradation after 30 days incubation with P. ostreatus in both autumn (27.1%) and winter (31.5%) harvest time. P. ostreatus pretreatment showed promising results for anaerobic digestion of giant reed achieving a cumulative yield of 130.9 NmL g−1 VS for the winter harvest, whereas I. lacteus showed a decrease in methane yield as compared with the untreated biomass (77.4 NmL g−1 VS and 73.3 NmL g−1 VS for winter and autumn harvest, respectively). I. lacteus pretreatment resulted in a loss of both holocellulose and lignin, indicating that this strain was less selective than P. ostreatus. Further studies are necessary to identify white rot fungi more suitable to lignocellulosic biomass and optimize biological pretreatment conditions to reduce its duration.

A Comparison between Numerical Simulation Models for the Prediction of Acoustic Behavior of Giant Reeds Shredded

Giant reeds represent a natural fiber widely available in some areas of the world. Its use can be particularly useful as the uncontrolled growth of giant reeds can be a problem because large areas are invaded by them and the crops are damaged. In this study, two models of numerical simulation of the acoustic behavior of giant reeds were put in comparison: the Hamet model and a model based on artificial neural networks. First, the characteristics of the reeds were examined and the procedures for the preparation of the samples to be analyzed were described. Then air flow resistance, porosity and sound absorption coefficient were measured and analyzed in detail. Finally, the results of the numerical modeling of the acoustic coefficient were compared. The neural network-based model showed high Pearson correlation coefficient value, indicating a large number of correct predictions.

Mechanical Harvesting Line Setting of Giant Reeds

This study evaluated the possibility of adopting haymaking farming machinery in giant reed (Arundo donax L.) harvesting. The test shows the technical and energy aspects of mechanical harvesting using only one specific machine, a shredding machine, designed and developed by an Italian constructor for large biomass herbaceous crops (giant reed, sorghums, switchgrass, Mischantus, etc). It is designed for high vegetative growth crops, as it is able to spread products over all soil surfaces or, alternatively, carry out windrowing. Tests were conducted in the south of Italy (Campania region) on the experimental farm Torre Lama in Bellizzi (SA). Biomass was shredded, dried in the field, and baled for use in a logistic chain and storage. The first step was the cutting and shredding of biomass crops with the specific shredder rear-mounted in an agricultural tractor. The biomass then was dried on the field, constantly monitored for moisture content, and finally, baled with a trailed round baler for storage (second step) and used in a specific logistic chain. The test showed good performance of the shredder machine between 1.17 and 1.77 ha h−1 with an operative speed between 3.9 and 5. 9 km h−1. To define the hourly production, a high wet production level of 60.70 t ha−1 and a low level of 56 t ha−1 were used as references. Under the climatic conditions of the experimental test, this harvesting system showed some advantages, such as the possibility of immediate and long-term biomass storage (less than 14% moisture content), the potential alternative use of the biomass, and the reduced resource use compared to that of other ordinary crops growing in the area.

Identification of indicators of giant reed (Arundo donax L.) ecotypes for phytoremediation of metal-contaminated soil in a non-ferrous mining and smelting area in southern China

An investigation of giant reed (Arundo donax L.) in a non-ferrous mining and smelting area in southern China was carried out to select indicators to identify ecotypes suitable for phytoremediation in terms of their morphology, biochemistry, and sustainability. Giant reed populations were found to be able to survive in extremely contaminated soils in the studied non-ferrous mining and smelting area of southern China, with soil pH ranging from 2.9 to 9.59, cadmium (Cd) content of up to 525 mg/kg, and lead (Pb) content of up to 57194 mg/kg. The giant reed population at Hunan (HN), with a soil Cd content of up to 2.3 mg/kg, and that at Yunnan (YN), with a soil Pb content of up to 33.8 mg/kg, were selected as suitable sources of ecotypes with high phytoremediation potential in the studied area’s soil. The leaf area, height, and photosynthetic pigment content of plants of the HN and YN ecotypes were not significantly affected by metal contamination compared to some other populations, while the malondialdehyde (MDA) content of giant reeds was increased by up to 30 μmol/g by Cd and Pb contamination. In the results of a principal component analysis (PCA) of all the giant reed indicators assessed, the different giant reed ecotypes were most clearly identified by the biochemical and morphological indicators included in principal component 2. The biochemical and morphological indicators of giant reed, including their leaf area, height, and content of malondialdehyde (MDA) and chlorophyll a could thus be regarded as decisive indicators for the identification of giant reed ecotypes, which was confirmed by a further detrended correspondence analysis (DCA) and redundancy analysis (RDA). The irregular granular excretion was also a reliable indicator of giant reed ecotypes with phytoremediation potential, especially of the solid ecotypes examined using a scanning electron microscope (SEM). The identified indicators were consistent with the finding that these giant reed ecotypes could be pseudo-metallophytes. In addition, the level of genetic variation was not significantly reduced by heavy metal accumulation, identifying a sustainability of a giant reed population. Considering the similarity in the proportion of cellulose content, the giant reed could also be widely used as bioenergy crop producing abundant cellulose for the economical phytoremediation of large areas of non-ferrous contaminated soil. The methods and conclusions of this study could also serve as a reference and source of guidance for the identification of indicators of other plants with promising phytoremediation potential.

Genetic Diversity, Cytogenetics, and Biomass Yields among Taxa of Giant Reeds (Arundo Species)

Genetic diversity and cytogenetics of 31 accessions of Arundo L., collected from North America and South Asia, were characterized using 20 intersimple sequence repeat (ISSR) markers, flow cytometry, and cytology. In addition, field trials of 23 Arundo donax L. accessions were established in 2011 and harvested in 2012 to 2013 to assess annual biomass yields. Cluster analysis, based on Jaccard’s similarity coefficient method, clearly differentiated Arundo formasana Hack. from A. donax and a third unidentified Arundo taxon. Arundo donax further contained two subgroups representing North American (naturalized and cultivated) and South Asian collections. Within each A. donax subgroup, genetic distances were very low (0.03 for North America and 0.07 for South Asia). Principle coordinate analysis further supported distinct clusters. Relative genome sizes were determined using Pisum sativum L. as the reference genome and 6-diamidino-2-phenylindole (DAPI) fluorochrome. Chromosome numbers (2n), ploidy levels, and 2C relative genome sizes ranged from ≈62 to 105, near 12x to near 18x, and 2.78 to 4.13 pg, respectively, and were similar within each taxa/subgroup. While there was a low level of genetic variability among A. donax accession, dry biomass yields varied significantly ranging from 6.5 to 65 Mg·ha−1 per year for the third growing season.

The correlation between cellulose allomorphs (I and II) and conversion after removal of hemicellulose and lignin of lignocellulose

H2SO4, NaOH and H3PO4 were applied to decompose lignocellulose samples (giant reeds, pennisetum and cotton stalks) to investigate the correlation between cellulose allomorphs (cellulose I and II) and conversion of cellulose. The effect of removal of hemicellulose and lignin on the surface morphology, crystallinity index (CrI), cellulose allomorphs (cellulose I and II), and enzymatic hydrolysis under different pretreatments was also studied. CrI caused by H3PO4 pretreatment reached 11.19%, 24.93% and 8.15% for the three samples, respectively. Corn stalk showed highest conversion of cellulose among three samples, irrespective of the pretreatment used. This accounted for the widely use of corn stalk as the renewable crop substrate to synthesize biofuels like ethanol. CrI of cellulose I (CrI-I) negatively affects cellulose conversion but CrI of cellulose II (CrI-II) positively affects cellulose conversion. It contributes to make the strategy to transform cellulose I to cellulose II and enhancing enzymatic hydrolysis of lignocellulose.

Bending test for capturing the vivid behavior of giant reeds, returned through a proper fractional visco-elastic model

This paper presents results of experimental investigations made to evaluate the vivid behavior of giant reed Arundo donax. In particular, attention was paid to the relationship between visco-elastic properties and moisture content, which is widely recognized as one of the key factor that influences the mechanical properties of all wood-based materials. To this aim, after a controlled drying treatment on samples of reed, stress relaxation tests in three point bending configuration were performed to evaluate the effects of moisture content on visco-elastic behavior of the giant reed. Further, the novel aspect of this paper is that of using an Euler–Bernoulli model embedded with an advanced visco-elastic constitutive law to fit experimental data of bending tests. Such a model of continuum beam takes into account different constitutive laws of viscoelasticity, being natural materials visco-elastic.

Use of Green Material for Acoustic Correction inside Rooms

The green materials are products obtained by the transformation of materials of vegetable origin; and they have the advantage that at the end of their useful life, they are scattered in the environment without causing damage. In this work the green material considered and used from acoustic application, is made from giant reeds of sweet water (arundo donax). The giant reeds have been cut, dried and shredded, and a loosened granular material has been obtained, which is very porous, and it presents good characteristics, both in thermal isolation and in acoustic absorption. This paper shows giant reeds application in the room acoustic. Panels with giant reeds shredded were made and they were used in a classroom for the reduction of reverberation time. DOI: http://dx.doi.org/10.5755/j01.sace.3.4.4708

Xenobiotic phytoremediation in marine environments: Potential impact of climate changes

An investigation of giant reed (Arundo donax L.) in a non-ferrous mining and smelting area in southern China was carried out to select indicators to identify ecotypes suitable for phytoremediation in terms of their morphology, biochemistry, and sustainability. Giant reed populations were found to be able to survive in extremely contaminated soils in the studied non-ferrous mining and smelting area of southern China, with soil pH ranging from 2.9 to 9.59, cadmium (Cd) content of up to 525 mg/kg, and lead (Pb) content of up to 57194 mg/kg. The giant reed population at Hunan (HN), with a soil Cd content of up to 2.3 mg/kg, and that at Yunnan (YN), with a soil Pb content of up to 33.8 mg/kg, were selected as suitable sources of ecotypes with high phytoremediation potential in the studied area’s soil. The leaf area, height, and photosynthetic pigment content of plants of the HN and YN ecotypes were not significantly affected by metal contamination compared to some other populations, while the malondialdehyde (MDA) content of giant reeds was increased by up to 30 μmol/g by Cd and Pb contamination. In the results of a principal component analysis (PCA) of all the giant reed indicators assessed, the different giant reed ecotypes were most clearly identified by the biochemical and morphological indicators included in principal component 2. The biochemical and morphological indicators of giant reed, including their leaf area, height, and content of malondialdehyde (MDA) and chlorophyll a could thus be regarded as decisive indicators for the identification of giant reed ecotypes, which was confirmed by a further detrended correspondence analysis (DCA) and redundancy analysis (RDA). The irregular granular excretion was also a reliable indicator of giant reed ecotypes with phytoremediation potential, especially of the solid ecotypes examined using a scanning electron microscope (SEM). The identified indicators were consistent with the finding that these giant reed ecotypes could be pseudo-metallophytes. In addition, the level of genetic variation was not significantly reduced by heavy metal accumulation, identifying a sustainability of a giant reed population. Considering the similarity in the proportion of cellulose content, the giant reed could also be widely used as bioenergy crop producing abundant cellulose for the economical phytoremediation of large areas of non-ferrous contaminated soil. The methods and conclusions of this study could also serve as a reference and source of guidance for the identification of indicators of other plants with promising phytoremediation potential.

Low-Input Production of Biomass from Perennial Grasses in the Coastal Plain of Georgia, USA

Warm-season perennial grasses are a promising source of biomass for energy production in Southeast USA, and low-input production is desirable. With only residual fertility in the soil and no irrigation, this test compared biomass yields of eight grasses under low-input production: L 79–1002 energycane (Saccharum hyb.), Merkeron and N51 napiergrass (Pennisetum purpureum Schum.), three clones of giant reed (Arundo donax L.), and two switchgrass (Panicum virgatum L.) lines. For the first 2 years napiergrass maintained dry matter (DM) yields over 25 Mg DM ha−1 year−1, and energycane yielded over 20 Mg DM ha−1year−1 for 3 years. Switchgrass yields were lower (8.6 Mg DM ha−1 year−1 average of 4 years), but the biomass contained less moisture at harvest than the other, larger-stemmed grasses. Switchgrass biomass also had the lowest concentrations of N, K, and ash. Average yields of giant reeds were also low (6.4 Mg DM ha−1 year−1), while ash and N concentrations were relatively high compared with switchgrass and energycane. In 4 years of production, energycane and napiergrass removed between 269 and 386 kg N ha−1 and 830–1,159 kg K ha−1, while the other grasses removed significantly less of these nutrients. Giant reed removed 126 kg N ha−1 and 193 kg K ha−1, and switchgrass removed 83 kg N ha−1 and 140 kg K ha−1. In Southeast USA, it is possible to produce biomass from perennial grasses with minimal inputs but the high nutrient removal rates of some species suggest that it may not be sustainable for long periods of time.

USING CONSTRUCTED WETLANDS TO IMPROVE DRAINAGE WATER QUALITY FROM HYDROPONICS FARMS

ABSTRACTIn this work, two types of pilot constructed wetlands were used to treat drainage water from the hydroponics farm in the Jordan Valley. Zeotuff was used as wetland filtering media. The wetlands were planted with giant reeds (Arundo donax L.). The performance of the wetland systems under varying hydraulic retention times (HRT) was investigated in terms of BOD, COD, NO3, PO4, cations, anions, TSS, salinity and water conservation. It has been found that the vertical flow wetland was able to reduce the biochemical oxygen demand (BOD5) concentration by more than 93% at an HRT of 7 days, where the BOD5 removal was about 89% by the horizontal flow wetland at the same HRT. The percentage removal of total suspended solids (TSS) was found to be 98 and 94% by the vertical and horizontal flow wetlands, respectively. Nutrient content (nitrate and phosphate) was reduced in both wetlands at lower HRTs by more than 77%. Both wetlands obtained high efficiency in chemical oxygen demand (COD) removal as the quality of effluent water was found to comply closely with the Jordanian Irrigation Guidelines. The wetlands were able to greatly reduce the cations and anions contained in the influent water. The vertical flow wetland system exhibited more efficiency as a treatment facility than the horizontal flow wetland system. Copyright © 2010 John Wiley &amp; Sons, Ltd.

Effect of operational and design parameters on removal efficiency of pilot-scale FWS constructed wetlands and comparison with HSF systems

In order to investigate the effect of temperature, hydraulic residence time (HRT), vegetation type, substrate material and wetland shape on the performance of free-water surface (FWS) constructed wetlands treating wastewater, 5 pilot-scale units were constructed and operated continuously from December 2004 until March 2007 in parallel experiments. Four of the units (A, B, C, D) were rectangular in plan view with dimensions 3.40 m in length and 0.85 m in width, and contained substrate material at a thickness of 0.45 m. The fifth unit (E) had a trapezoidal plan view shape, with a width at the inlet of 1.15 m and at the outlet of 0.55 m, while the length and the thickness of the substrate were the same as in the other four. All units operated at a water depth of 0.10 m. Units B–E contained clay substrate and unit A contained sand. The four units with clay were planted as follows: two with cattails (B and E), one with common reeds (C), and one with giant reeds (D). Unit A, containing sand, was planted with cattails. Planting and substrate material combinations were appropriate for comparison of the effect of vegetation and material type on the function of the system. Synthetic wastewater was introduced in the units. During the operation period four HRTs (i.e., 6 days, 8 days, 14 days and 20 days) were used, while wastewater temperatures varied from about 0.0 °C to 29.1 °C. The removal performance of the five constructed wetland units was good, since it reached on the average 77.5%, 67.9%, 60.4%, 53.9%, 56.0% and 51.7% for BOD, COD, TKN, ammonia (NH 4-N), ortho-phosphate (PO 4-P) and total phosphorus (TP), respectively. BOD and phosphorus removal efficiencies showed dependence on temperature in most units. The 14-day HRT was found adequate for acceptable removal of organic matter, nitrogen and phosphorus for most temperatures. A 20-day HRT is recommended for acceptable removal of BOD and PO 4-P in the cold season. The unit with the trapezoidal plan view shape showed the best performance, with mean removals of 80.1%, 73.5%, 70.4%, 68.6%, 64.7% and 63.5% for BOD, COD, TKN, NH 4-N, PO 4-P and TP, respectively. The cattail was found statistically more efficient than the other two plants in COD and PO 4-P removal. The unit that contained the clay substrate was found statistically more efficient in phosphorus removal than the unit containing sand. HSF CW units were found more efficient than FWS units in removal of most pollutant.

Analysis of Phosphorus Behavior in the Giant Reed for Phytoremediation and the Biomass Production System

Macrophyte-cultivated wetlands have a strong potential not only to purify eutrophic water but also to produce biomass resources. Among a variety of macrophytes, we focused on the giant reed (Arundo donax), and its properties of phosphorus uptake, accumulation, and translocation were clarified in this study. Phosphorus uptake experiments using outdoor hydroponic culturing showed the seasonal variation of phosphorus uptake by the giant reed. Furthermore, two kinetic parameters describing the phosphorus uptake by the giant reed were obtained. Phosphorus accumulation experiments using radioactive phosphorus suggested that giant reeds accumulate the absorbed phosphorus in rhizomes, and it is then distributed to the leaves if needed. A phosphorus translocation experiment using radioactive phosphorus indicated that the decreasing of phosphorus in the leaves occurred in the order of location from the bottom to the top, which is relevant to the order of dying down of the plant leaves actually observed in this study. Based on these outcomes, a desirable management method for the giant reed cultivated in wetlands is proposed.

Arundo donax L. stress tolerance under irrigation with heavy metal aqueous solutions

This study investigates the influence of widely ranged soil cadmium and nickel content on the biomass quantity and quality produced by Arundo donax L. (giant reed). The aim was to determine whether giant reed is hypertolerant to these heavy metals and therefore could exploit polluted sites, which could not be used for food production, by producing useful biofuel. A 2-year pot experiment was held in the field and an automated drip irrigation system was established to provide daily the plants with aqueous solutions of cadmium and nickel in concentrations of 5, 50 and 100 mg l −1, against the control (tap water). At the end of each experimental year the soil total Cd and Ni content was determined and ranged between 13.5 mg kg −1 Cd and 68.5 mg kg −1 Ni (low treatment — first year) and 973.8 mg kg −1 Cd and 2543.3 mg kg −1 Ni (high treatment — second year). During both growing periods the number of branches was recorded. In mid October of each year the plants were harvested and the plant height and the fresh and dry weight of stems, leaves, branches, root system, above ground part and total plant were determined. Also, giant reeds biomass allocation, moisture content (%) and water use efficiency were measured. The observed morphological and biomass characteristics were smaller than those reported in literature due to the fact that the plants were grown in pots. Nevertheless, all measured parameters did not differ among treated and control plants, indicating the high tolerance ability of that species to the examined metals.