Experimental Research on the Application of Water Hyacinths to the Ecological Restoration of Water Bodies with Eutrophication

[Objective] The study aims to discuss the application of water hyacinths to the ecological restoration of water bodies with eutrophication through simulation experiments. [Method] In this study, water hyacinths were used to restore the simulated eutrophic water with green algae as the dominant algae species, and then the restoration effect of the simulated eutrophic water by water hyacinths was analyzed. [Result] In the simulation test without sediment, the peak chlorophyll concentration was 434.6 mg/m3 in the tank without water hyacinths, which decreased to 285 and 119 mg/m3 respectively in the tanks with 1 and 4 water hyacinths. In the experiment with sediment, compared with the control tank without water hyacinths, a 58% reduction in chlorophyll concentration could be observed in the tank with 4 water hyacinths planted (with a coverage of 51%). The results showed that water hyacinths could inhibit alga growth notably, but there was likely a density threshold (51% coverage), and no significant eco-restoration effect was observed in the simulated eutrophic water with too few water hyacinths planted. [Conclusion] The research could provide scientific references for the ecological restoration of eutrophic water bodies.

Integrated biological control of water hyacinths, Eichhornia crassipes by a novel combination of grass carp, Ctenopharyngodon idella (Valenciennes, 1844), and the weevil, Neochetina spp.

The efficacy of grass carp Ctenopharyngodon idella （Cyprinidae） and weevils Neochetina spp. （Curculionidae） to control the aquatic weed, water hyacinth, is investigated in a square net cage （happas） setting at a farm in Cuddalore District, South India. This novel combination of insects and fish is found to be superior to individual treatments for controlling the weed growth within ll0 d. The biomass of the weed, number of plants, percentage of flowered plants and chlorophyll contents were studied. The weed biomass is reduced from 5 kg （day 1） to 0.33 kg （day 110） when exposed to grass carp and weevils. The number of plants is reduced to 0.75 in grass carp and weevil exposed happas, while it is 741.5 in the control. The mean number of leaves per plant is also reduced. In addition, the chlorophyll a and b are significantly reduced in happas exposed to the combination of fish and insects when compared to the other treatments. Based on the results of this study, we consider the combined use of grass carp and weevils to be more efficient and sustainable for managing water hyacinths than the use of these organisms individually.

Assessment of Electric Power Generation via Water Hyacinths and Agricultural Waste

The importance and the necessary of researches on renewable energy have become a hot topic in recent years due to climate change and global warming. In addition, the fossil fuel reserves is facing rapid depletion on the earth. Currently, most researches have concentrated on producing biogas for heating, lighting, drying, cooking but lack in researching on electricity production because the possibility of producing biogas at households are common at small scale. Studying on alternative energy sources to replace traditional fuel for electric power generation brings new chances and great opportunities for development. This study presents an assessment electric power generation via water hyacinths and agricultural waste. In this paper, the evaluation electric power is generated by operating internal combustion engines which use biogas fuel to replace traditional fuel （diesel, gasoline）. The results of the studies were demonstrated by experiments on the renewable energy production system at Hoa An Biotechnology Research and Experimental Center of Cantho University.

Long-Term Environmental Impacts of Pesticide and Herbicide Use in Panama Canal Zone

The opening of the Panama Canal in 1913 transformed ocean-shipping and the availability of internationally-traded goods, shortened travel time between the Pacific and Atlantic oceans, increased ship tonnage, and sparked the growth of port authorities on both the Atlantic and Pacific coasts of the Panama Canal. Historically, the United States was number one and China was number two in tons of cargo that pass through the canal annually in the high stakes game of import and export markets. Prior to the construction of the Panama Canal, the most efficient way to cross the 82-kilometer isthmus, between the Port of Panama City on the Pacific and the Port of Colon on the Atlantic, was by mule trails through tropical forests and river transportation. Since the construction of the Panama Canal through tropical forests in the 1910s, pesticides have been essential for managing mosquitoes as well as controlling wetland vegetation that blocked lakes, rivers and the canal. The primary objective of this research study is to document the long-term environmental impacts of pesticide and herbicide use in the Panama Canal Zone. Many of these chemicals, including 2, 4,-D, 2, 4, 5-T and DDT, have a long half-life under water and some, like arsenic (As), have no half-life. Pesticides and chemicals flowed into Lake Gatun via surface runoff either in solution or attached to the sediment during the rainy season. The by-product 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) is an unanticipated contaminant created during the manufacture of the herbicide 2,4,5-T. TCDD can bio-accumulate in fish and birds and enter into the human food supply. The extent of the current chemical and pesticide contamination on former U.S. military base grounds and in Lake Gatun is unknown. Systematic soil sampling of current and former military bases, chemical disposal sites and Lake Gatun or the Panama Canal sediments is needed to determine if mitigation is necessary.

Ultrafast Spectral Studies of the Primary Processes of Photosynthesis in Spinach and Water Hyacinth Leaves

The authors have studied the spectroscopic characteristics and the fluorescence lifetime for the chloroplasts from spinach (Spinacia oleracea L.) and water hyacinth (Eichhornia crassipes (Mart) Solms.) plant leaves by absorption spectra, low temperature steady_state fluorescence spectroscopy and single photon counting measurement under the same conditions. The absorption spectra at room temperature for the spinach and water hyacinth chloroplasts are similar, which show that different plants can efficiently absorb light of same wavelength. The low temperature steady_state fluorescence spectroscopy for the water hyacinth chloroplast reveals a poor balance of photon quantum between two photosystems. The fluorescence decays in PSⅡ measured at the natural Q A state for the chloroplasts have been fitted by a three_exponential kinetic model. The slow lifetime fluorescence component is assigned to a collection of associated light harvesting Chl a/b proteins, the fast lifetime component to the reaction center of PSⅡ and the middle lifetime component to the delay fluorescence of recombination of P + 680 and Pheo -. The excited energy conversion efficiency (η) in PSⅡ RC is 87% and 91% respectively for the water hyacinth and spinach chloroplasts calculated on the 20 ps model. This interesting result is not consistent with what is assumed that the efficiency is 100% in PSⅡ RC. The results in this paper also present a support for the 20 ps electron transfer time constant in PSⅡ RC. On the viewpoint of excitation energy conversion efficiency, the growing rate for the water hyacinth plan is smaller than that for the spinach plant. But, authors' results show those plants can perform highly efficient transfer of photo_excitation energy from the light_harvesting pigment system to the reaction center (approximately 100%).

Effect of Growing Media on Growth and Flowering of Different Hyacinth Cultivars （Hyacinthus orientalis L.）

A pot experiment has been conducted in Faculty of Agricultural and Forestry, Lath House of Horticultural Department, School of Plant Production, Duhok University during the growing season 2010-2011. The study consisted of testing the effects of four different growth media （Clay, Loam, Clay ＋ sheep manure （1：1） and Loam ＋ sheep manure （1：1） as volumetric rates on vegetative and flowering growth characters of five different cultivars of Hyacinths plant （Blue Giant, City of Haarlem, Jon Bos, Delf Blue and Fondante）. The experiment was laid out in randomized complete block design （RCBD） of two factors in three replicates. Media mostly affected the parameters studied during the experiment. Early emergence （22.53 days） and flowering （73.13 days） was recorded in medium consisting of loam and sheep manure, while maximum plant height （19.75 cm）, leaves number （6.13）, leaf area （31.47 cm2） were recorded in clay medium. Maximum number of florets plant-l （31.93） and spike length （7.95 cm） were recorded in medium consist of clay and sheep manure. Maximum length of spike stem （9.61 cm） and total chlorophyll percentage （53.45%） were recorded for loam medium. Among the cultivars, some parameters showed significant variation. Early emergence （20.42 days）, maximum plant height （20.35 cm）, leaf area per plant （33.01 cm2） and length of spike stem （15.10 cm） were given by cv. Fondante. Maximum number of florets plantl （35.58） and spike lengths （8.63 cm） were recorded by cv. Blue Giant. High percentage of total chlorophyll （58.15%） was recorded in cv. Jon Bos..

Invasion and control of water hyacinth (Eichhornia crassipes)in China

By the time of primary 21st century, water hyacinth had become a serious environmental problem in China. Water hyacinth contributes to the major part of ecological hazards from the invasion of foreign plant species, which is estimated about USD 7 billion a year in values. In the past 10 years, herbicides glyphosate, 2,4-D and paraquat have been used in controlling water hyacinth in China. Al- though the herbicides provided effective control on the weed in some areas, they could not provide the sustainable inhibition on the weed population, while would lead to pollution on water at various levels. At present, the herbicide application on water hyacinth is forbidden in many areas of China such as Shanghai. In this situation, the asexual reproduction inhibitor, KWH02, was invented for controlling water hyacinth and it provided about 70% of growth inhibition without any risk of dead plant pollution. It has been about 10 years for bio-control of water hyacinth in China. Works focused on mainly the efficacy and safety of the utilization of foreign insects. Researches on microorganism herbicides to control water hyacinth were started and obtained primary achievements in recent years. Although there are different opinions on how to face the water hyacinth problem in China, it is accepted widely that the control methods should be high efficient and safe with low cost. Some practical measures for integrated management of water hyacinth are suggested.

Performance of a water hyacinth(Eichhornia crassipes)system in the treatment of wastewater from a duck farm and the effects of using water hyacinth as duck feed

Nowadays, intensive breeding of poultry and livestock of large scale has made the treatment of its waste and wastewater an urgent environmental issue, which motivated this study. A wetland of 688 mz was constructed on an egg duck farm, and water hyacinth （Eichhornia crassipes） was chosen as an aquatic plant for the wetland and used as food for duck production. The objectives of this study were to test the role of water hyacinth in purifying nutrient-rich wastewater and its effects on the ducks＇ feed intake, egg laying performance and egg quality. This paper shows that the constructed wetland removed as much as 64.44% of chemical oxygen demand （COD）, 21.78% of total nitrogen （TN） and 23.02% of total phosphorus （TP）. Both dissolved oxygen （DO） and the transparency of the wastewater were remarkably improved, with its transparency 2.5 times higher than that of the untreated wastewater. After the ducks were fed with water hyacinth, the average daily feed intake and the egg-laying ratio in the test group were 5.86% and 9.79% higher, respectively, than in the control group; the differences were both significant at the 0.01 probability level. The egg weight in the test group was 2.36% higher than in the control group （P 〈 0.05）, but the feed conversion ratios were almost the same. The eggshell thickness and strength were among the egg qualities significantly increased in ducks fed with water hyacinth. We concluded that a water hyacinth system was effective for purifying wastewater from an intensive duck farm during the water hyacinth growing season, as harvested water hyacinth had an excellent performance as duck feed. We also discussed the limitations of the experiment.

Anatomical studies on water hyacinth (Eichhornia crassipes (Mart.) Solms) under the influence of textile wastewater

Water hyacinth (Eichhornia crassipes (Mart.) Solms) is a prolific free floating aquatic macrohpyte found in tropical and subtropical parts of the earth. The effects of pollutants from textile wastewater on the anatomy of the plant were studied. Water hyacinth exhibits hydrophytic adaptations which include reduced epidermis cells lacking cuticle in most cases, presence of large air spaces (7～50 μm), reduced vascular tissue and absorbing structures. Textile waste significantly affected the size of root cells.The presence of raphide crystals was noted in parenchyma cells of various organs in treated plants.

Can Water Hyacinth Clean Highly Polluted Waters? —A Short Paper for Discussion

Recently local government and environmental protection authorities in China have turned to the water hyacinth, one of the world’s worst aquatic weeds, to reduce nutrient concentrations in highly eutrophic lake waters, especially in Lake Dian in southwestern China’s Yunnan Province. Although we do not reject using water hyacinth to reduce lake eutrophication, it is not a complete solution. In our view, a more complete solution requires a holistic consideration of watershed or drainage characteristics, and a solid understanding of the limnological features of individual lakes. Before the bio-geochemistry and toxicological effects of water hyacinth be thoroughly understood, applying it widely to lake restoration and overstating its practical value is not only irresponsible but also dangerous.

Biogas Production Using Water Hyacinth (Eicchornia crassipes) for Electricity Generation in Kenya

Water hyacinth, E. crassipes, an invasive water weed thrives in fresh water bodies causing serious environmental problems. In Kenya the weed has invaded Lake Victoria and poses great socioeconomic and environmental challenges. Currently the weed is harvested from the Lake and left in the open to rot and decay leading to loss of aesthetics, land and air pollution. There is therefore need for development of value addition and economic exploitation strategies. The aim of the study is to assess the potential for utilization of the weed as a renewable energy resource for biogas production. Samples were collected from Lake Victoria, pulped and blend with cow dung at a ratio of 3:1 as inoculum. The resultant mixture was mixed with water at a ratio of 1:1 and fed into a 6 m3 tubular digester. The digester was recharged with 20 kg after every three days. The temperature, pH variations, gas compositions, upgrading and gas yields were studied. The temperature ranged between 22.8°C - 36.6°C and pH 7.4 - 8.5. Biogas was found to contain 49% - 53% methane (CH4 ), 30% - 33% carbon dioxide (CO2 ), 5% - 6% nitrogen (N2 ) and traces of hydrogen sulphide (H2S). The biogas was upgraded using solid adsorbents and wet scrubbers increasing the methane content by up to 70% - 76%. The upgraded gas was used to power internal combustion engines coupled with an electricity generator and direct heat applications. The study concludes that E. crassipes is a potential feedstock for biogas production especially in areas where it is abundant.

Sorption of Manganese （II） and Chromium （III） Ions from Aqueous Solution Using Water Hyacinth Biomass （Eichhornia crassipes）

The use of water hyacinth biomass as adsorbent for Cr3＋ and Mn2＋ ions from aqueous solution by means of batch-adsorption technique was investigated to determine the potential ability of the biomaterial for metal ion removal. The equilibrium isotherm study showed that the maximum monolayer coverage on the biomass surface was 0.933 mg·g-1 and 0.874 mg·g-1 for Mn2＋ and Cr3＋ ions respectively. The highest percentage of Cr3＋ and Mn2＋ ions adsorbed by the biomass was 86.4% and 82.6% at the optimum pH of 4.0 and 6.0 respectively. The results also showed that the highest percentage removal 82.5% and 78.3% was obtained at 30 and 20 minutes respectively for Cr3＋ and Mn2＋ ions. The sorption process was examined by means of the Langmuir model. The adsorption equilibrium data were found to follow the Langmuir isotherm model with high coefficients of determination （R2 = 0.990 and 0.999） for Cr＋ and Mn2＋ ions respectively. The adsorption capacity of water hyacinth showed that water hyacinth will be useful in recovering chromium （III） and manganese （II） ions from solution and their subsequent removal from industrial effluents.

Cr(VI) Ions Removal from Aqueous Solutions Using Natural Adsorbents – FTIR Studies

The ability of eight natural adsorbents were investigated for adsorptive removal of Cr(VI) from aqueous solutions. Various physico-chemical parameters such as pH, initial metal ion concentration, adsorbent dose level and equi-librium contact time were optimized in batch adsorption technique. A detailed Fourier Transform Infrared Spectrophotometer (FTIR) study of adsorbents and Cr(VI) loaded adsorbents at the optimized condition was carried out to identify the different functional groups that were responsible for the adsorption. The important functional groups like hydroxyl, alkene, aromatic nitro, carboxilate anion, silicon oxide, sulphonic acid etc. were present in the natural adsorbent and were responsible for the chemical adsorption of Cr(VI) from aqueous solutions. The sorption energy calculated from Dubinin-Radushkevich isotherm indicated that the adsorption process were chemical in nature.

Extraction and Application of Natural Mordant Dyes from Eichhornia Crassipes(Water Hyacinth)

Metallic salts are often added as extra mordant when dyeing the fabrics with natural dyes. Eichhornia crassipes,namely water hyacinth( WH),is an environmentally problematic aquatic weed with high affinity for metals. In this paper,WH was selected as the source of natural mordant dyes,and extracted by absolute ethyl alcohol using a soxhlet apparatus. The colorants in WH were extracted and separated by column chromatography and thin layer chromatography( TLC). UV-visible spectrophotometer( UV-VIS),mass spectrometry, chemical identification with chromogenic reaction,and Fourier transform infrared spetroscopy( FTIR) were used to identify the main components of each pigment band. The total metal contents before and after extracting of the WH were determined by using an inductively coupled plasma atomic emission detector. The WH extracts were then used to dye wool fabric. The dyeing properties of WH extracts with and without metal mordant were investigated and compared. The results show that the main components of WH extracts are pheophytin and phyllins. The major metallic elements identified in WH are magnesium, manganese,zinc,and iron. Samples dyed with WH extracts without metal mordant exhibits high K / S values and good dyeing properties. This study indicates that the WH extracts can be used as a natural mordant dye on wool fabrics directly.

The Effect of Water Hyacinth (<i>Eichhornia crassipes</i>) Compost on Tomato (<i>Lycopersicon esculentum</i>) Growth Attributes, Yield Potential and Heavy Metal Levels

The potential of different water hyacinth compost application rates in influencing growth attributes, yield and heavy metal accumulation of lead (Pb), copper (Cu), nickel (Ni) and zinc (Zn) in tomato fruit was studied in Masvingo. Four treatments of water hyacinth compost rates of 0, 37, 55.6 and 74.1 t·ha-1 were each replicated three times and applied in a randomized complete block design set up. Results showed that water hyacinth compost application rates significantly affected plant height, days to maturity and yield but had no influence on the number of tomato fruits per plant. The plant height at application rate of 74.1 t·ha-1 was 25%, 56% and 63% higher than the control at week 6, 9 and 12, respectively. At application rates of 56.6 t·ha-1, plant heights were 11%, 13% and 12% higher than the control whilst marginal plant height differences of -4%, 6% and 4% were recorded between application rate of 34.7 t·ha-1 and the control at week 6, 9 and 12, respectively. Tomato plants under compost rates of 34.7, 56.6 and 74.1 t·ha-1 in comparison to the control delayed maturity by 10, 17 and 20 days, respectively. Yields of 52, 55, 60 and 68 t·ha-1 were realized from hyacinth compost rates of 0, 34.7, 56.6 and 74.1 t·ha-1, respectively. Heavy metal concentrations increased with increase in the water hyacinth compost rate but at all application rates, the average concentrations were 85%, 93% and 86% lower than the Codex Alimentarious Commission permissible levels for Pb, Cu and Zn. Water hyacinth compost at a rate of 74 t·ha-1 therefore can be used for increased tomato yield without exposing consumers to heavy metal toxicity.

A Comparative Study of ESTs Induced under Drought and Salinity Stress in Hyacinth Bean (<i>Lablab purpureus</i>)

Abiotic stressors like drought and salinity are major causes for loss of agricultural productivity. Comparison of expressed sesquence tags (ESTs) under different abiotic stresses provides insight into underlying mechanism of stress response, and candidate genes to improve tolerance to abiotic and biotic stresses via breading and transgenic methods. In order to identify and compare stress-specific ESTs from drought and salinity stressed Hyacinth Bean, ten days old seedlings were subjected to respective stresses and RNA was extracted from control and stressed leaves for EST identification. 31 and 12 ESTs, respectively, were characterized from leaves of drought and salinity stressed seedlings of Hyacinth Bean, Lablab purpureus by differential display RT-PCR using identical combinations of 48 primers and validated using quantitative RT-PCR. Relative fold expression was higher under salt stress than drought stress. Whereas 19 EST overexpressed under drought, 12 EST were down regulated. Of the 12 EST under salinity, 9 EST were downregulated and 3 EST upregulated. Putative functions predicted from sequence homology indicated that 11 drought specific EST corresponded to metabolic functions, and 4 of them corresponded to transcription regulation. Under salinity, 4 and 2 EST, respectively, corresponded to metabolic and RNA associated functions. Under both stresses, there were ESTs associated with unknown functions, whose characterization may throw light on the regulatory mechanism. Differing number of ESTs differentially expressed under drought and salt stress, and their predicted functionalities, suggested distinct set of response genes involved under these two stresses, despite a good number of physiological players being common. From the predicted functions of ESTs, the paper attempts to explain the possible mechanism of response of Hyacinth Bean to these two stresses.

Adsorption of Caffeine and Ciprofloxacin onto Pyrolitically Derived Water Hyacinth Biochar： Isothermal, Kinetic and Thermodynamic Studies

In this work, the adsorptive features of water hyacinth （Eichhornia crassipes） derived biochar for sequestration of ciprofloxacin and caffeine from aqueous solution is reported. The isothermal behaviour, adsorption kinetics, mechanisms and thermodynamic parameters were investigated in batch mode. Langmuir and Freundlich models described the equilibrium adsorption data with regression values 〉 0.9. The kineticsdata obeyed the pseudo-second-order kinetic law while intraparticle pore diffusion was not the only rate controlling step. The computed thermodynamic parameters, namely change in Gibbs free energy （AG）, change in enthalpy （AH） and change in entropy （AS） indicated that the adsorption processes were spontaneous and exothermic with less randomness, pH dependence studies depicted multi-mechanistic adsorption for both compounds and is hypothesized to involve hydrophobic interactions besides other non-coulombic interactions. The findings demonstrate that water hyacinth biochar presents an excellent low cost and environmentally benign adsorbent for mitigation of pharmaceuticals from water with a removal efficiency of above 60 % for caffeine and ciprofloxacin.

Ethanol Production Process by Lignocellulosic Material Fermentation from Water Hyacinth Biomass

In order to take advantage of the lignocellulosic material in water hyacinth （Eichhornia crassipes）, dehydration pretreatment in the first step and then sodium hydroxide and hydrogen peroxide pretreatment was performed. The microorganism used for the fermentation process was Zimomonas mobilis. Batch fermentation experiments were carried out with four tests using 22 factorial design with two levels leadings to evaluate the effect of NaOH concentration, conditioning salts as independent variables and ethanol produced as a dependent variable. The optimum condition with higher amount of glucose hydrolyzed and ethanol was： substrate conditioning cellulases, it was pretreated 10% NaOH, with 92.38% conversion of glucose to ethanol and yield of 0.47 g ethanol per g of glucose and 0.018 g ethanol per g of biomass.

Evaluation of Sunlight and Humidity Protection of a Bioherbicide for Eichornia crassipes Biocontrol

C. piaropi （Cercospora piaropi） and A. zonatum （Acremonium zonatum） have proved to be effective in reducing water hyacinth growth. However, efficacy of these fungi in field is limited by the effect of solar UV （ultraviolet） light and desiccation. In this study, three compounds used as sunscreens and one seed plant that produce mucilage were tested for their effects on the infection produced by C. piaropi and A. zonatum inoculum under laboratory and field conditions. In laboratory conditions, TiO2 （titanium dioxide） and metamucil did not inhibit C. piaropi and A. zonatum viability. Moreover, the addition of TiO2 and metamucil to the inoculum suspension increased fungi infection. The protective effect of TiO2 and metamucil was more evident when the inoculum suspension was applied 4 h before sunset. These results suggest that addition of TiO2 and metamucil provides necessary humidity and solar protection for increasing C piaropi and A. zonatum infection on water hyacinth plants.

Field Utilization of Dried Water Hyacinth for Phosphorous Recovery from Source-Separated Human Urine

This research demonstrated the feasibility of converting source-separated human urine into a solid fertilizer by means of continuous absorption and solar thermal evaporation using dried water hyacinth as adsorbent. In a preliminary experiment, the dried petioles of water hyacinth (DWH) absorbed urine in a mean rate of 18.78 ml·g-1 within 7 d, retrieving about 3.46% urine dissolved solids (UDS). In an advanced experiment, the DWH’s capacity of urine absorption declined from an initial 2.73 L·kg-1·d-1 to 0.68 L·kg-1·d-1, with a requirement of material change in about 25 effective days and an average ratio of 25 (L) to 1 (kg). Phosphorus (P2O5) concentration in the adsorbent increased from 0.46% (material baseline) to 3.14% (end product), suggesting a satisfactory recovery of the element. In field application, the urine was discharged, not in wet weather, onto the DWH via a tube connected to a waterless urinal. There are several ways to use the UDS-DWH as P(K)-rich fertilizer, e.g., making soluble fertilizer for foliage spraying to encourage prolific flowering and fruiting. Apparently, utilization of water hyacinth waste to recover dissolved plant nutrient elements from source-separated urine will benefit the environment in a wide range of perspectives. The herein innovative use of water hyacinth is also expected to be useful in the recycling of certain dissolved hazardous materials.