Investigating the Effects of Eichhornia Crassipes Biodiesel and Liquefied Petroleum Gas on the Performance and Emissions of a Dual-Fuel Engine

This study considers the effect of Eichhornia Crassipes Biodiesel(ECB)blends on the performances,combustion,and emission characteristics of a direct injection compression ignition engine operated in a dual-fuel mode(DFM)and equipped with an Exhaust gas recirculation technique(EGR).In particular,a single-cylinder,four-stroke,water-cooled diesel engine was utilized and four modes of fuel operation were considered:mode I,the engine operated with an ordinary diesel fuel;mode II,the engine operated with the addition of 2.4 L/min of lique-fied petroleum gas(LPG)and 20%EGR;mode III,20%ECB with 2.4 L/min LPG and 20%EGR;mode IV,40%ECB with 2.4 L/min LPG and 20%EGR.The operation conditions were constant engine speed(1500 rpm),var-iation of load(25%,50%,75%,and 100%),full load,with a compression ratio of 18,and a time injection of 23°BTDC(Before top died center).With regard to engine emissions,carbon dioxide(CO_(2)),carbon monoxide(CO),hydrocarbons(UHC),and nitrogen oxide(NOX)were measured using a gas analyzer.The smoke opacity was measured using an OPABOX smoke meter.By comparing the results related to the different modes with mode I at full load,the BTE(Brake thermal efficiency)increased by 20.17%,11.45%,and 12.66%with modes II,III,and IV,respectively.In comparison to the results for mode II,the BTE decreased due to the combustion of ECB blends by 7.26%and 6.24%for mode III and mode IV,respectively,at full load.In comparison to mode II,the Brake specific energy consumption(BSEC)increased with the ECB substitution.With ECB blends,there is a noticeable decrease in the CO,CO_(2),and UHC emissions at a partial load.Furthermore,the 20%ECB has no effect on CO emissions at full load.For modes II and IV,the CO_(2)increased by 33.33%and 19%,respectively,while the UHC emissions were reduced by 14.49%for mode III and 26.08%for mode IV.The smoke of mode III was lower by 7.21%,but for mode IV,it was higher by 12.37%.In addition,with mode III and mode IV,the NOx emissions increased by 30.50%and 18.80%,respectively.

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.

Allelopathic Effects of Eichhornia crassipes on the Growth of Microcystis aeruginosa

Algal blooms caused by eutrophication in fresh water are one of the major environmental problems in the world. Using biological methods to control algal growth, especially based on allelopathic inhibitory effects of aquatic macrophytes on phytoplankton growth, have been received world-wide attention. In this study, the allelopathic activity of the invasive macrophyte, Eichhornia crassipes （water hyacinth）, on blue-green algae, Microcystis aeruginosa （PCC7806） was investigated using coexistence assay. Our results showed that water hyacinth had disparate effects on the growth ofM~ aeruginosa （PCC7806） under different initial algal densities. Under lower initial algal density （OD650 = 0.10 and OD650 = 0.05）, the algal growth was significantly inhibited by water hyacinth （inhibition ratio was 95.6% and 97.3%, respectively）. While it was stimulated at higher initial algal densities （OD650 = 0.20）. Water hyacinth inhibited the growth of algae mainly through its root system. Culture water from water hyacinth and aqueous methanol extracts from dry roots samples also showed inhibition effects on algal growth. The inhibition effects increased as the increase of crude extract concentration, suggest that water hyacinth may excrete inhibitory substances from root system and show allelopathic inhibitory potential to the growth ofM. aeruginosa.

A NOVEL STEROID FROM EICHHORNIA CRASSIPES

6 -Hydroxy-stigmasta-4,22-diene-3-one 1,a novel steroid, was isolated from the Eichhornia Crassipes.Its structure was deter- mined by ~1H and ^(13)C NMR spectroscopy and further confirmed by authen- tic sample,which was synthesized from stigmasterol 2.

Effects of Eichhornia crassipes Growth on Aquatic Plants in Dianchi Lake

[Objective] The aim was to study the effects of Eichhornia crassipes as an invasive plant on aquatic plants in Dianchi Lake. [Method] Based on the determination of chlorophyll content of phytoplankton and submerged plant (Potamogeton pectinatus) in Dianchi Lake in different months, the effects of E. crassipes on aquatic plants in Dianchi Lake were studied, and the allelopathy effect of root culture solution of E. crassipes on Microcystis aquaticum was discussed. [Result] The growth of E. crassipes in Dianchi Lake reduced the chlorophyll content of phytoplankton and submerged plant (P. pectinatus), and it showed that E. crassipes had certain inhibitory effect on their growth; the culture solution of E. crassipes root inhibited M. aeruginosa growth obviously. [Conclusion] The study could provide scientific references for the prevention and control of ecological safety of E. crassipes.

Evaluation of Growth Rate of Invasive Aquatic Macrophytes and Contribution to Its Use in Organic Fertilizer Production: A Case of Eicchornia crassipes (Mart.) Solms, 1883 in the Lobé Creek (Littoral-Cameroon)

From 20 January to 20 July 2023, a study was carried out on the Lobé Creek, a waterway subject to considerable natural and man-made pressures, with a negative impact on its biodiversity and habitats. The aim was to evaluate the growth rate of invasive aquatic macrophytes and their contribution to the use of organic fertilisers: a case of Eicchornia crassipes (Mart.) Solms, 1883 in the Lobé Creek (Littoral-Cameroon) with a view to its appropriate use in agronomy. The specific objective was to examine the impact of anthropogenic actions on Lobé Creek, characterise physico-chemical environment of the study area, and evaluate the growth rate of E. crassipes and its chemical composition with a view to producing an organic biofertiliser. The results show that E. crassipes represents a considerable threat to the populations of these localities. As for the physico-chemical parameters, the temperature values vary from 24 ± 1.41˚C to 26.5 ± 1.13˚C;pH from 6.3 ± 0.1 to 7.2 ± 0.07;conductivity and dissolved oxygen vary respectively from 40.7 ± 1.83 µS/cm to 19.6 ± 3.11 µS/cm and from 7.3 ± 0.14 mg/l to 5.8 ± 1.55 mg/l. Its average growth rate varies from 0.69 feet/day to 0.63 feet/day. With regard to the nitrogen, phosphorus and potassium content of water hyacinth plants, the results show that the average total nitrogen content ranges from 6.11 ± 1.59 g/kg to 5.2 ± 2.03 g/kg;total phosphorus, from 0.52 ± 0.54 g/kg to 0.88 ± 0.38 g/kg;and potassium, from 1.43 ± 0.45 g/kg to 2.61 ± 0.89 g/kg.

The effects of two free-floating plants (Eichhornia crassipes and Pistia stratiotes) on the burrow morphology and water quality characteristics of pond loach (Misgurnus anguillicaudatus) habitat

Loach exhibit conspicuous drilling behaviors in the mud of shallow waters,yet their burrow morphology and the factors affecting this behavior have received little attention.We characterized the burrow morphology and water quality of the pond loach Misgurnus anguillicaudatus in three scenarios:in tanks without plants,tanks with the free-floating plant water hyacinth Eichhornia crassipes,and tanks with water lettuce Pistia stratiotes.Water hyacinth effectively removed water TN,COD,NO3-N and NH4-N,and water lettuce removed water TP and NH4-N.Water hyacinth and water lettuce markedly reduced water turbidity and DO,increased TOC and EC.Water hyacinth purified water more effectively than water lettuce,providing a suitable habitat for loach feeding,living and burrowing.The burrow structures were V-shaped,Y-shaped,inverted L-shaped,or complicated dendritic networks composed of multiple V shapes.The hyacinth treatment was characterized by the greatest burrow volume,length,depth,and structural complexity,but the opening size was reduced by dense root mat coverage.Burrows in the water lettuce treatment were characterized by intermediate volume,length,branches and sinuosity,but they had the largest opening and pit size.The control treatment had a flat bottom with the smallest,shortest burrows.This study indicates that free-floating plants improve habitat suitability and change burrow morphology and may be used to improve loach breeding methods。

Chemical Composition of the Neochetina eichhorniae and Neochetina bruchi and Their Potential for Use as Livestock Feed

Neochetina eichhorniae and Neochetina bruchi have been used for over four decades as Eichhorniae crassipes classical biological control agents globally. Despite the success of bio-control against the water hyacinth globally at different levels and environmental sustainability, biological control against water hyacinth seems to have overlooked the socio-economic sustainability in assisting the ravaged communities, gain resilience and adapt to the challenges of the invasive alien species. This manuscript evaluates the potential to draw out more from biological control of the water hyacinth by evaluating the potential to utilize Neochetina eichhorniae and Neochetina bruchi as feed. The live insects of the two species were collected from the water hyacinth marts in the nearby L. Victoria in Siaya county, Kenya. Where they were then transferred for semi-cultivation in localized ponds for reproduction and closer monitoring. The ponds having been set up in completely randomized design while in the open within the same climatic region mimicked the water quality and most abiotic conditions of the lake necessary for the insects’ and host plant acclimatization and reproduction. The samples for proximate analysis were collected from these ponds as per the research and experimental design. The chemical compositions of the Neochetina bruchi, N. eichhorniae and their larvae composite, satisfactorily compared to basic fish feed requirements, specifically as a protein source having crude protein (CP) percentage per DM of 55.0350 ± 0.025, 54.4350 ± 0.035 and 62.2750 ± 0.025 respectively.

凤眼莲入侵对洪湖湿地CO_(2)、CH_(4)、N_(2)O通量的影响初探

为揭示外来植物入侵对湖泊湿地温室气体排放的影响机制,选择入侵植物样地和本土植物样地,通过漂浮箱-气相色谱法原位研究了洪湖湿地温室气体排放规律及其控制因子,探讨了外来入侵植物对洪湖湿地温室气体排放的影响。结果表明,外来植物凤眼莲(Eichhornia crassipes)入侵洪湖湿地后,CO_(2)通量高于开阔水域,但低于挺水植物区莲+菰群落和浮水植物区欧菱群落;入侵植物区凤眼莲群落监测点CH_(4)通量高于浮水植物区欧菱群落监测点,但低于开阔水域和莲+菰群落监测点;凤眼莲群落监测点N_(2)O通量均低于莲+菰群落、欧菱群落和开阔水域监测点。相关分析表明,莲+菰群落和凤眼莲群落监测点CO_(2)通量与温度显著正相关,莲+菰群落监测点N_(2)O通量与温度显著正相关,而4个监测点CH_(4)通量与环境因子无显著相关性。洪湖湿地CH_(4)排放通量(1.11~534.40 mg·m^(-2)·h^(-1))比通常观测到的数值高1~2个数量级,可能是由于该湖泊湿地水体污染严重,湖泊呈富营养化。

Study on the Feeding Intensity of Grass Carp at Different Physiological Stages on Water Hyacinth ( Eichhornia crassipe )

[Objectives]This study was conducted to investigate the feeding intensity of different sizes of grass carp on water hyacinth.[Methods]Grass carp of 10 sizes,i.e.,50,100,150,200,250,300,350,400,450 and 500 g,were put in cages.Thirty grass carp were stocked in each cage,and only water hyacinth was fed.The grass carp were caught after 120 d,and the food intake and growth of the grass carp were analyzed.[Results]The body weight of all sizes of grass carp increased significantly,and the overall length of grass carp increased significantly.Compared with feeding feed,the body length and body weight in the experimental treatments were lower,and they were more slender;and the feed coefficient of small-sized grass carp was slightly larger than that of large-sized grass carp.When the stocking size was above 414.7 g,the net weight gain of grass carp increased rapidly,and the total food intake also increased.[Conclusions]This study provides a theoretical basis for achieving an ideal purification effect of water hyacinth on aquaculture water by maintaining the growth of grass carp and the biomass and coverage of water hyacinth within suitable ranges.

凤眼莲、大薸对水体重金属复合污染的富集及去除效果研究

研究了凤眼莲（Eichhorniacrassipes）和大藻（Pistiastratiotes L．）对水体中Hg^2＋、pb^2＋、Cd^2＋、Zn^2＋、Cu^2＋、复合污染的富集和去除效果。结果显示：凤眼莲和大藻对5种重金属的富集系数都较大，凤眼莲的富集系数大小顺序为Pb^2＋〉Zn^2＋〉Cd^2＋〉Hg^2＋〉Cu^2＋，大藻的富集系数大小顺序为pb^2＋〉Cd^2＋〉Zn^2＋〉Hg^2＋〉Cu^2＋。凤眼莲对5种重金属离子的最大去除率分别为〉95．45％、98．33％、90．40％、84．64％、27．43％，大藻的最大去除率分别为〉95．45％、97．23％、84．00％、84．53％、38．54％。凤眼莲、大藻与对照组相比去除率差异均极显著（P〈O．01），而2种植物间去除率差异不显著（P〉0．05）。除了cu^2＋之外其他4种离子（Hg^2＋、Pb^2＋、Cd^2＋、Zn^2＋）在4～12d内从0．0011、0．1359、0．0125、0．2780mg／L。降到了符合《渔业水质标准》。

In-situ nitrogen removal from the eutrophic water by microbial-plant integrated system

Objective: This study was to assess the influence of interaction of combination of immobilized nitrogen cycling bacteria (INCB) with aquatic macrophytes on nitrogen removal from the eutrophic waterbody, and to get insight into different mechanisms involved in nitrogen removal. Methods: The aquatic macrophytes used include Eichhornia crassipes (sum-mer-autumn floating macrophyte), Elodea nuttallii (winter-growing submerged macrophyte), and nitrogen cycling bacteria in-cluding ammonifying, nitrosating, nitrifying and denitrifying bacteria isolated from Taihu Lake. The immobilization carriers materials were made from hydrophilic monomers 2-hydroxyethyl acrylate (HEA) and hydrophobic 2-hydroxyethyl methylacrylate (HEMA). Two experiments were conducted to evaluate the roles of macrophytes combined with INCB on nitrogen removal from eutrophic water during different seasons. Results: Eichhornia crassipes and Elodea nuttallii had different potentials in purification of eutrophic water. Floating macrophyte+bacteria (INCB) performed best in improving water quality (during the first experiment) and decreased total nitrogen (TN) by 70.2%, nitrite and ammonium by 92.2% and 50.9%, respectively, during the experimental period, when water transparency increased from 0.5 m to 1.8 m. When INCB was inoculated into the floating macrophyte system, the populations of nitrosating, nitrifying, and denitrifying bacteria increased by 1 to 2 orders of magnitude compared to the un-inoculated treatments, but ammonifying bacteria showed no obvious difference between different treatments. Lower values of chlorophyll a, CODMn, and pH were found in the microbial-plant integrated system, as compared to the control. Highest reduction in N was noted during the treatment with submerged macrophyte+INCB, being 26.1% for TN, 85.2% for nitrite, and 85.2% for ammonium at the end of 2nd experiment. And in the treatment, the populations of ammonifying, nitrosating, nitrifying, and de-nitrifying bacteria increased by 1 to 3 orders of magnitude, as compared to the un-inoculated treatments. Similar to the first ex-periment, higher water transparency and lower values of chlorophyll a, CODMn and pH were observed in the plant+ INCB inte-grated system, as compared to other treatments. These results indicated that plant-microbe interaction showed beneficial effects on N removal from the eutrophic waterbody.

Heavy Metal Accumulation Potential of Some Wetland Plants Growing Naturally in the City of Kolkata, India

Freshwaters are not only used locally in many developing countries but they are often over exploited for domestic purposes, agriculture and disposal of industrial wastes which result in an overload of excess nutrients, harmful chemicals and heavy metals. Plant species together with sediments and water samples collected from eleven aquatic water bodies in the vicinity of industrial units in Kolkata were studied for their potential to uptake Pb, Cd and Cr under field conditions. Cd and Cr concentrations in the sediments were higher than background values considered to be toxic. Alternanthera philoxeroides and Eichhornia crassipes were the two invasive species present, with the former being more widely distributed. Among native plants, Ipomoea aquatica was the most abundant. Metal uptake in the plants differed among species, tissues and sites. Pb and Cd accumulation in root tissues for all plants in most sites suggested an exclusion strategy for metal tolerance. Since I. aquatica is widely consumed in many parts of SE Asia, its metal content should be checked before use since it was found to efficiently translocate both Pb and Cd from roots to shoots. The potential of A. philoxeroides as a metal excluder needs to be explored further since it translocates less to its shoots as compared to E. crassipes and I. aquatica.

不同浓度脱水剂处理对凤眼莲脱水效果及氮磷元素的影响

将一种新型脱水剂应用于凤眼莲(Eichhorniacrassipes)脱水,并用自动进样器和iCAP7600电感耦合等离子体发射光谱仪,分别通过定氮蒸馏法和微波消解法来测量凤眼莲样品鲜重以及氮磷含量.结果表明:凤眼莲样品经脱水剂以30μL∙m^(-2)用量处理过后,在4~6 d后便可出现明显的叶片枯黄、茎秆萎蔫等症状,其鲜重在脱水12 d后下降了约50%.而凤眼莲样品经脱水剂以60μL∙m^(-2)和120μL∙m^(-2)用量处理12 d后,其氮和磷的含量变化并不显著,这说明用该脱水剂处理凤眼莲不会给外部环境带来氮磷富集的影响.