氧化塘生物处理污水及回用

植物水浮莲具有较强的耐污、吸污能力 ,在氧化塘污水处理系统中生长良好 ,经处理的含油污水出水排放基本达到TB T30 0 7- 2 0 0 0《铁路回用水质标准》的要求。污水处理运行费较低 ,管理方便 ,出水水质好 ,污水再回收利用 。

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%).

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.

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.

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.

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.

Separated Hydrolysis and Fermentation of Water Hyacinth Leaves for Ethanol Production

Water hyacinth is a raw material for long-term sustainable production of cellulosics ethanol. In this study, the acid pretreatment and enzymatic hydrolysis were used to evaluate to produce more sugar, to be fermented to ethanol. Separated hydrolysis and fermentation （SHF） studies were carried out to produce ethanol from water hyacinth leaves. Dilute sulfuric acid pretreatment and enzymatic hydrolysis were conducted to select the optimum pretreatment conditions. The optimum pretreatment conditions included T = 135 ℃, t = 30 min, and sulfuric acid concentration = 0.1 M. The residue was enzymatically hydrolyzed using the mixture of enzymes cellulase, xylanase and pectinase. The maximum enzymatic saccharification of cellulosic material （76.8%） was achieved. SHF by mono-culture of Saccharomyces cerevisiae KM1195 achieved the highest yields of ethanol. Furthermore, ethanol production was accomplished with the co-culture ofS. cerevisiae TISTR5048 and Candida tropicalis TISTR5045 which produced the highest increase in ethanol Yield. In this case, the ethanol concentration of 3.42 （g/L）, percentage of the theoretical ethanol yield of 99.9%, the ethanol yield of 0.27 g/g and the productivity of 0.22 g/L/h were obtained. This suggested that mild acid pretreatment and co-cultureare promising methods to improve enzymatic hydrolysis and ethanol production from water hyacinth.

The Effect of Water Hyacinth （Eichhornia Crassipes） Infestation on Phytoplankton Productivity in Lake Naivasha and the Status of Control

The paper presents data collected in an assessment of the effects of water hyacinth （Eichhornia crassipes） infestation on phytoplankton productivity in Lake Naivasha. A summary of the status of control and strategies used is given. The ecological effects of water hyacinth on the lake have received little attention compared to the large body of work available on the weed＇s socioeconomic impact. This study was conducted to determine the effect of hyacinth infestation on the phytoplankton productivity. Several sampling stations were set up in the lake at sites containing floating mats of the weed and at sites where the weed was absent. Phytoplankton chlorophyll-a concentration and dissolved oxygen were measured at each station and used as proxies for phytoplankton productivity. The findings show that phytoplankton productivity in weed covered areas is reduced with significant change in species composition and biodiversity suggesting that water hyacinth can alter the ecology of the lake. Although water hyacinth has continued posing serious ecological consequences, the control strategies already adopted will continue to reduce deleterious impacts and allow sustained development in the Lake Naivasha Basin. There is need however to undertake research to quantify the level of ecological damage and the costs of control. There are other effects such as livelihood loss, diseases, and disruption of normal operations that also need to be quantified.

Study on Aerobic Composting of Mixed Municipal Sludge, Kitchen Waste and Water Hyacinth

In this study, a in vessel aerobic composting method is adopted to investigate the variation rules of various evaluation parameters （temperature, moisture content, pH, organic matter, water soluble ammonia nitrogen, water soluble nitrate nitrogen and germination index） in cocomposting of municipal sludge, kitchen waste and water hyacinth at different proportions. The results show that, in composting, the parameters of moisture content, pH, water soluble ammonia nitrogen and water soluble nitrate nitrogen demonstrate marked dynamic change rules during composting process; the temperature of three groups of compost materials rapidly rise to above 55 ~C within 96h, and last for 3 - 7d, meeting the harmless requirements, and their organic matter degradation rate excess 30%, the GI index is higher than 83%, in line with the requirements on maturity, which proves that the co-composting of municipal sludge, kitchen waste and water hyacinth can realize harmlessness and resource reutilization after composting.

再论“司南”

指南针是我国的伟大发明。王振铎设计的"司南"模型号称是它的雏形。但这一设计全然不合理,其中的勺形器竟然是用电磁铁做的。其所据之《论衡》"司南之杓"一语,实应为"司南之酌",有宋刊本和萧梁·吴均诗为证。"杓"既然是错字,所以建立在这一认识基础上的设计完全落空。"司南之酌"指司南车在地上行驶,与磁勺毫无关系。近来有人认为汉代以前我国的科学技术水平制造不出指南车,这个看法亦无充足的科学依据。又有人认为"司南之酌"是以磁针和小葫芦瓢组成的水浮指南仪,也只是根据推理提出的想法,无任何考古材料作支持。此类武断和臆测之说,科技史家实应引以为戒。因为在发明指南针这种大事件中,添上一些不实之词,反而会降低其可信性,不利于加强我们的文化自信。