High-rate composting-vermicomposting of water hyacinth (Eichhornia crassipes,Mart. Solms)

In an attempt to develop a system with which the aquatic weed water hyacinth (Eichhornia crassipes, Mart. Solms) can be economically processed to generate vermicompost in large quantities, the weed was first composted by a 'high-rate' method and then subjected to vermicomposting in reactors operating at much larger densities of earthworm than recommended hitherto: 50, 62.5, 75, 87.5, 100, 112.5, 125, 137.5, and 150 adults of Eudrilus eugeniae Kinberg per litre of digester volume. The composting step was accomplished in 20 days and the composted weed was found to be vermicomposted three times as rapidly as uncomposted water hyacinth [Bioresource Technology 76 (2001) 177]. The studies substantiated the feasibility of high-rate composting-vermicomposting systems, as all reactors yielded consistent vermicast output during seven months of operation. There was no earthworm mortality during the first four months in spite of the high animal densities in the reactors. In the subsequent three months a total of 79 worms died out of 1650, representing less than 1.6% mortality per month. The results also indicated that an increase in the surface-to-volume ratio of the reactors might further improve their efficiency.     

水葫芦对藻类的克制效应

水葫芦对藻类生长有克制作用。其机制主要是由于水葫芦根系向水体分泌的有机物质能伤害和杀死藻类。用水葫芦种植水培养藻类,使藻类的光合作用速率显著降低,叶绿素a破坏,细胞还原TTC的能力下降。在荧光显微镜下可看到藻细胞从鲜红色变为淡蓝绿色。     

Mineral nutrient demands of the water hyacinth (Eichhornia crassipes (Mart.) Solms) in the White Nile

The possibility that the stunted growth of the water hyacinth in Bahr el Ghazal river in Sudan is influenced by nutrient elements is considered. Greenhouse experiments were carried out to determine the effects of deficiency and mineral nutrient additions on the growth of this plant. The water hyacinth was found to grow at a wide range of nutrient levels. Maximum growth was recorded at 21 mg l^–1 N, 62 mg l^–1 P, and 0.60 mg l^–1 Fe.     

Allelopathic influence of algae on the growth of Eichhornia crassipes (Mart.) Solms

The growth of Eichhornia crassipes (Mart.) Solms was inhibited when grown in water containing algae such as Scenedesmus bijugatis (Turp.) Kuetz, Chlorella pyrenoidosa Chick and species of Aphanothece, Euglena, Merismopedia and Coelastrum. The size of plants, their dry weight and chlorophyll a and b contents and their rate of vegetative propagation were very much reduced compared with control plants grown in algae-free water. The hyacinth plants ultimately died after 90–100 days of growth with algae.     

Growth of water hyacinth (Eichhornia crassipes (Mart.) Solms) in the middle Paraná River (Argentina)

The productivity of water hyacinth in the middle Paraná River was measured at three initial biomass levels by means of periodic harvesting of plants contained in 2 m² floating baskets. The measuring period extended between August 1981 and July 1982. Initial biomass densities were 2, 5 and 10 kg (fw) m^–2.Compared with inner island ponds, flowing waters connected to the main river showed better conditions for water hyacinth growth. The duration of the growth period was some 30% longer than in island ponds, probably due to the relatively warmer river waters. Productivity ranged between 108 and 164 g (fw) m ^–2 d^–1 (annual average) for the lower and higher initial biomass values, respectively.     

Effect of rhizobacteria on arsenic uptake by macrophyte Eichhornia crassipes (Mart.) Solms

Wastewater flowing in streams and nallahs across India carries several trace metals, including metalloid arsenic (As), which are considered serious environmental contaminants due to their toxicity, and recalcitrant nature. In this study, we determined the phytoremediation of As by Eichhornia crassipes (Mart.) Solms either alone or in association with plant growth-promoting rhizobacteria. Pseudomonas and Azotobacter inoculation to E. crassipes resulted in enhanced As removal compared to uninoculated control. Co-inoculation with a consortium of Pseudomonas, Azotobacter, Azospirillum, Actinomyces, and Bacillus resulted in a higher As (p < 0.05) phytoaccumulation efficiency. P. aeruginosa strain jogii was found particularly effective in augmenting As removal by E. crassipes. Our findings indicate that the synergistic association of E. crassipes and various rhizobacteria is an effective strategy to enhance removal of As and thus may be utilized as an efficient biological alternative for the removal of this metalloid from wastewaters.     

Evapotranspiration by Eichhornia crassipes (Mart.) Solms and Typha latifolia L.

Evapotranspiration (E) by Eichhornia crassipes (Mart.) Solms and Typha latifolia L. growing in 5.77-m² tanks and evaporation (E₀) from control tanks were measured over a 6-month period at Auburn, Alabama (32.5° N latitude). The E/E₀ ratios for E. crassipes and T. latifolia were 1.31–2.52 (mean = 1.75) and 1.05–2.50 (mean = 1.62), respectively. Evidence is presented which demonstrates that E/E₀ values were similar to those which occur in natural populations of the two species. Both plant characteristics and meteorological variables influenced evapotranspiration. Equations for estimating evapotranspiration were E_Ec = (4.19 + (7.32 × 10⁻⁸) S² + (0.00035 × 10⁻³)H²)D R² = 0.92E_Tl = (1.43 + (2.79 × 10⁻¹⁵)S⁴ + 1.44L)D R² = 0.93 where E_Ec and E_Tl are monthly water loss in mm/month for E. crassipes and T. latifolia, respectively; S is the average daily solar radiation in W m⁻² integrated over 24 h for the month; H is plant height in m; L is leaf area index (dimensionless); and D is the number of days in the month.     

Production of biogas from water hyacinth (Eichhornia crassipes) (Mart) (Solms) in a two-stage bioreactor

A two-stage rumen-derived anaerobic digestion process was tested for the conversion of water hyacinth shoots and a mixture of the shoots with cowdung (7:3) into biogas. Under conditions similar to those of the rumen and loading rates (LR) in the range of 11.6–19.3g volatile solids (VS) l–1d–1 in the rumen reactor, the degradation efficiencies were 38% for the shoots and 43% for the mixture. The major fermentation products were volatile fatty acids (VFA) with a maximum yield of 7.92mmolg–1 VS digested, and biogas with a yield of 0.2lg–1 VS digested. The effect of varying LR, solid retention time (SRT) and dilution rates on the extent of degradation of the water hyacinth–cowdung mixture was examined. Overall conversion of the substrate was highest at the loading rate of 15.4gVS.l–1d–1. Varying the retention times between 60 and 120h had no effect on the degradation efficiency, but a decrease was observed at retention times below 60h. The overall performance of the reactor was depressed by changing the dilution rate from 0.5 to 0.34h–1. By applying a LR of 15.4VS. l–1d–1, a SRT of 90h and a dilution rate of 0.5h–1 in the rumen reactor, and connecting it to a methanogenic reactor of the upflow anaerobic sludge blanket type, 100% conversion efficiency of the VFA into biogas with a methane content of 80% was achieved. The average methane gas yield was 0.44lg–1 VS digested.     

The silent invasion of Eichhornia crassipes (Mart.) Solms. in Italy

This article provides general information and original data on the period of first introduction in Europe (1823–1825) and in Italy (first half of the 19th century), and on the current distribution and impacts in Italy of the invasive macrophyte Eichhornia crassipes. Two main pathways are responsible for the presence of this species in Italy: (i) introduction as an ornamental and (ii) research and use for phytoremediation. After a time lag of more than 100 years, E. crassipes has recently started invading the Italian freshwaters. A specific action plan for this species is required, including local eradication and awareness campaigns. Furthermore, regulations in the trade sector of invasive aquatic plant species need to be introduced and the possibilities for biological or integrated control evaluated.     

Production of biogas from water hyacinth (Eichhornia crassipes) (Mart) (Solms) in a two-stage bioreactor

World Journal of Microbiology and Biotechnology - A two-stage rumen-derived anaerobic digestion process was tested for the conversion of water hyacinth shoots and a mixture of the shoots with...     

Seasonal variation in the nitrate content of water hyacinth (Eichhornia crassipes [Mart.] solms)

Water hyacinth was cultured in a flow-through system with constant nutrient availability and 1.4 mg 1^?1 NO₃-N as the nitrogen source. Tissue nitrate content ranged from 0.05 to 0.21% of dry wt. and accounted for 1.7–6.6% of the total nitrogen in the plant. Highest tissue nitrate levels occurred during the winter period of low plant growth rates and decreased as dry matter productivity increased. In the winter, the nitrate content of water hyacinth exceeded levels considered safe for conventional forage crops used for livestock feed.     

Allelopathic effects of water hyacinth [Eichhornia crassipes

Eichhornia crassipes (Mart) Solms is an invasive weed known to out-compete native plants and negatively affect microbes including phytoplankton. The spread and population density of E. crassipes will be favored by global warming. The aim here was to identify compounds that underlie the effects on microbes. The entire plant of E. crassipes was collected from El Zomor canal, River Nile (Egypt), washed clean, then air dried. Plant tissue was extracted three times with methanol and fractionated by thin layer chromatography (TLC). The crude methanolic extract and five fractions from TLC (A-E) were tested for antimicrobial (bacteria and fungal) and anti-algal activities (green microalgae and cyanobacteria) using paper disc diffusion bioassay. The crude extract as well as all five TLC fractions exhibited antibacterial activities against both the gram positive bacteria; Bacillus subtilis and Streptococcus faecalis; and the gram negative bacteria; Escherichia coli and Staphylococcus aureus. Growth of Aspergillus flavus and Aspergillus niger were not inhibited by either E. crassipes crude extract nor its five fractions. In contrast, Candida albicans (yeast) was inhibited by all. Some antialgal activity of the crude extract and its fractions was manifest against the green microalgae; Chlorella vulgaris and Dictyochloropsis splendida as well as the cyanobacteria; Spirulina platensis and Nostoc piscinale. High antialgal activity was only recorded against Chlorella vulgaris. Identifications of the active antimicrobial and antialgal compounds of the crude extract as well as the five TLC fractions were carried out using gas chromatography combined with mass spectroscopy. The analyses showed the presence of an alkaloid (fraction A) and four phthalate derivatives (Fractions B-E) that exhibited the antimicrobial and antialgal activities.     

Azotobacter chroococcum in the phyllosphere of water hyacinth (Eichhornia crassipes Mort. Solms)

Summary Water hyacinth (Eichhornia crassipes) harbours Azotobacter chroococcum in large numbers on and in its leaves. This may account for its prolific growth of the plants in water containing only traces of combined nitrogen. re]19721201     

Effects of 2,4-D on mature and juvenile plants of water hyacinth (Eichornia crassipes (Mart.) Solms)

The effects of various concentrations of the herbicide 2,4-D were investigated on two vegetative forms of water hyacinth including juvenile and mature forms. The results obtained suggest that efficient chemical control of water hyacinth may be best applied at the early stages of vegetative development of the water hyacinth, i.e. at the juvenile phase. This would require the use of 2,4-D at a concentration of 60 000 ppm (2.2 kg/ ha) which equals to half the rate of 2,4-D normally used for control of water hyacinth in the Sudan. The lower rate of 2,4-D not only means a considerable reduction in quantity and cost of the consumed herbicide but also a substantial minimisation in the level at which pollution may build up in the White Nile of the Sudan.     

Cyanide degradation by water hyacinths. Eichornia crassipes (Mart.) Solms

Summary Cyanide degradation by water hyacinths, Eichornia crassipes (Mart.) Solms, in solutions containing 3–300 mg/l cyanide was investigated in batch tests. Water hyacinth was more efficient to remove free cyanide in the first 8 hours, compared to cyanide controls, free of plant. Gold mill synthetic effluents containing free cyanide (9 to 20 mg/l), thiocyanate (14 to 23 mg/l), and metallocyanides (iron, copper and zinc) was fed to a continuous lab. scale unit (6 l/h) to confirm the ability of water hyacinth to degrade free cyanide and that it can remove zinc and small amounts of iron. However, copper and thiocyanate remained untouched in the solution. According to the results, water hyacinth is only suitable to be used in conjunction with other cyanide wastewater treatments.     

The effect of ionic form and level of nitrogen on the growth and composition of Eichhornia crassipes (Mart.) Solms

The average daily dry matter yield, percentage nitrogen and chlorophylla content of water hyacinths were found to differ significantly when cultured in nutrient solutions containing either NH₄-N or NO₃-N. Average daily ash-free dry matter yield, cell-wall fraction, and nonstructural carbohydrate content were not significantly affected by the ionic form in which nitrogen was supplied. Varying the amount of nitrogen supplied to the water hyacinths resulted in significant differences in yield and composition. Low supplies of nitrogen result in decreased yields and fibrous plants with lower nitrogen and higher nonstructural carbohydrate content.     

Abiotic and microbial decomposition of pre- and post-bloom leaves of water hyacinth (Eichhornia crassipes (mart.) Solms)

Rates of abiotic and microbial decomposition in pre- and post-bloom leaves of water hyacinth are determined under laboratory conditions. Decomposition in all types of hyacinth leaves is dominated by physical leaching in an initial phase of 4 days duration, and later by microbial processes. The largest part of physical leaching takes place within the first 4 h. Thereafter, the weight loss due to physical leaching declines exponentially. The weight loss by microbial decomposition is minimal in the initial phase but increases exponentially in the later phase. Pre-bloom leaves decompose significantly faster than post-bloom leaves, and post-bloom green leaves decompose faster than post-bloom brown leaves. The rate constants of abiotic decomposition are significantly higher in post-bloom leaves as compared with pre-bloom leaves, while microbial decomposition is significantly higher in pre-bloom leaves. After 30 days, the dry mass loss by abiotic and microbial decomposition is 15% and 55%, respectively, in pre-bloom leaves, 33% and 19% in post-bloom green leaves, and 24% and 6% in post-bloom brown leaves.     

Effect of nitrogen and fiber content on the decomposition of the waterhyacinth (Eichhornia crassipes [Mart.] Solms)

In situ rates of waterhyacinth decomposition were found to vary with tissue nitrogen and fiber content. High nitrogen (2.8%), low fiber (49%) waterhyacinth aerial tissues collected from a eutrophic site decomposed more rapidly than low nitrogen (1.3%), high fiber (58%) aerial tissues collected from a nutrient-poor site. In addition, waterhyacinth roots (65% fiber) decomposed much more slowly than aerial waterhyacinth tissues (49% fiber). Because the biomass distribution (aerial/root) and nitrogen and fiber content of waterhyacinths fluctuate both seasonally and with nitrogen availability, considerable temporal and site-to-site variability in decomposition dependent processes (e.g., sedimentation, mineralization) exist in aquatic systems infested by this species.     

Population dynamics of Eichhornia crassipes (C. Mart.) Solms in the Nile Delta,Egypt

The present study aims to evaluate the growth and seasonal allocation of the biomass of water hyacinth (Eichhornia crassipes) under natural conditions in the south Mediterranean region (the Nile Delta, Egypt). In this study, the population characteristics (density, morphology and primary production) over a one‐growing‐season cycle were described. In the Nile Delta, the biomass of the shoot and root systems of E.crassipes was sampled monthly along three water courses from April 2014 to November 2014 using five quadrats (each of 0.5 m × 0.5 m) at each water course. The shoot system started to grow in April (121 g/DM/m²), reached a maximum biomass of 887 g/DM/m² in July, and then decreased until reaching a minimum of 299 g/DM/m² in November. The biomass of the root system increased from 75 g/DM/m² in April to a maximum of 235 g/DM/m² in August and decreased to a minimum of 100 g/DM/m² in November. Water hyacinth allocated ca. 2% of its total biomass to stolons, 22% to laminae, 24% to roots and 52% to petioles. Peak density as high as 144 individual/m² occurred in May, but it reduced to 33–50 individual/m² during July to November. The average rate of change of biomass was maximum (17.3 g/DM/m²/day) during April and May and minimum (?8.9 g/DM/m²/day) during October and November. Relative growth rates were found to be lowest during the cooler months, October and November (?0.017 g/DM/g /day), whereas highest yields were recorded during the spring months, April and May (up to 0.044 g/DM/g/day). The correlation coefficients between the water characteristics and the first two canonical correspondence analysis axes indicated that the separation of the population parameters of water hyacinth along the first axis was negatively influenced by Zn. On the other hand, the second axis was positively correlated with electric conductivity, total N, total P, Mg, Na, K and Mn and negatively with pH.