In this dissertation, by using the method ofin the lab condition, the domestic sewage was direct aerated in testing equipment. The was cultivated step by step by controlling the environment conditions. During the process of cultivating , the laws of change and biodegradation characteristics of microorganism population were emPH atically analyzed according to the experiment PHenomenon. Observed and analyzed large amount of zoogloeas which appeared during the process of cultivating. The influences of load on main microbe by changing the load were studied.The results showed that: 1. The activated sludge was cultivated successfully in lab by controlling the environment conditions. The microbe evolved from low-grade to high-grade during the process of cultivating. 2. During the process of cultivating, the effluent quality indexes changed with the change of main microbial community. At the early stage of cultivating, the free cells were the main microbe. The effluent effect was not good. The removal rate of COD is 40%, of BOD is 26.6%. The sludge settleability was not good enough in Aeration Tank, the value of SV30 is 1.3%.At the medium stage of cultivating, the swimming type of ciliates were the main microbe. The structue of sludge is compacter than at the early stage of cultivating. The effluent effect was improving. The removal rate of COD is 60%, of BOD is 64.5%. The sludge’s SV30 in Aeration Tank is 5%. At the late stage of cultivating, the Vorticella like protozoan appeared and became the dominant population. marked the maturity of the activated sludge. The value MLSS achieved 1949.6mg/L. A large amount of branched zoogloeas made the flocs of activated sludge bigger. The removal rate of COD achieved 74%, of BOD achieved 74.2%. The sludge’s SV30 in Aeration Tank is 15%. The efficiency of sewage treatment is good.3. During the process of cultivating activated sludge, s appeared. The removal rate of COD increased remarkably. possesses stronger tolerance for water quality and shock loading ,which can enhance the reversibility of injured activated sludge.4. Observed the influences of changing organic load on main microbe, the results showed that high load can cause the nematode mass rearing, made the sludge abnormal and the effluent quality bad. Branched zoogloea possesses stronger tolerance for water quality and shock loading, so did not change.
Environmental and Natural Archive
A Study on Ozone Post-treatment of Chloronitrobenzene Manufacture Wastewater from Changshan Chemical Plant
Chloronitrobenzenes, as important building blocks for synthesis of industrial chemicals, are quite recalcitrant and toxic. They have been declared to be the priority persistent toxic substances(PTS) by the EPA of USA, EEC and China, and great interest is taken in the remediation technique. Chloronitrobenzenes are mainly produced in China and then supplid to the world. Chloronitrobenzene manufacture wastewater is generally treated by a pretreatment combined with biological treatment process. Performances of wastewater treatment system of Changshan Chemical Plant, one of the main chloronitrobenzene manufacturers, during the year 2004 and 2005 were evaluated. In order to decolorize the effluent of the wasterwater treatment system, ozone was applied for a post-treatment of the industrial effluent. Besides, removal ofand p-nitrophenol, the main pollutants of the wastewater by ozone was also investigated. The following results were achieved.1. Fe/C-A/O process was employed to treat chloronitrobenzene manufacture wasterwater from Changshan Chemical Plant. Operating results during the year of 2004 and 2005 indicated that this treatment system exhibited well performance for high concentrations of organic pollutants removal, and strong toelrance against fluctuating loadings. The results demonstrated that effluent quality from integrated process could meet the second standard of GB8978-96 with a removal effiency of 91.35% COD, 96.38% nitrobenzenes and 98.75% anilines. The main problem was that the effluent of the wastewater treatment system was still fairly colored.2. Rate constants of reaction of ozone with p-nitrophenol was found to increase with increasing solution pH.and ozone dosage but decrease with increasing the p-nitrophenol initial concentration. Temperature and radical scavenger has little effect on p-nitrophenol degradation. Direct ozone oxidization was predominant to indirect radical oxidation reaction during the degradation process of p-nitrophenol. Rate constants of reaction of ozone with also increased withincreasing solution pH.and ozone dosage but decrease with increasing the initial concentration.But indirect oxidization of radical was predominant to direct oxidation reaction during the degradation process of p-chloronitrobenzene. The difference of the reaction mechanism was probably due to the difference between the dissociation property of two reactants.3.Color could be efficiently removed by ozone as a result of the decomposition of main pollutants in effluent from Fe/C-A/O process of Chanshan Chemical Plant. Effluent quality could be improved by increasing ozone dosage and hydraulic retention time. Comparing with other ozonized reactors, the counterflow presented the best performances. Complete decolorization was achieved at ozone dosage of 100 mg/min and hydraulic retention time of 4 minutes with a removal efficiency of 89.3%. Operation cost for effluent decolorization was about 0.6 ~ 0.8 RMB/t wastewater. These results demonstrated that ozonized decolorization process exhibite the potential of full-scale application.
Study on Restoration Models of Vegetation and Their Characteristics in Typical Karst Rocky Desertification Area
The difference of climate inrocky desertification area in our country is bigger, and partial entironment is rich. The approach of restoring the vegetation was various. Therefore, studying the characteristics of different models and different succession stages of vegetation restoration in the different typical rocky desertification areas, and opening out the ecology rule, the physics and chemistry character of soil in different models can provide the important academic basis for combating the Karst rocky desertification.This paper mainly studies the characteristics of different stages of hill closing for forest, dendrocalamus latiflorus forest, bamboo-deciduous forest, zenia insignis forest, choerospondias axillary forest and agroforest model in Lingyun County Guangxi Zhuang Autonomous Region. Studies the characteristics of different stages of hill closing for forest, plum forest, cupressus duclouxiana forest and agroforest model in Puding County Guizhou Province. And studies the characteristics of different stages of hill closing for forest, armand pine forest and pine-deciduous forest in Fuyuan County Yunnan Province. Main conclusion as follows:(1) In the last succession stage of hill closing for forest, the plant in different layers is neuter and forbearing shade species. But the difference of species composition in different stages in the three studying place is bigger. There are mainly evergreen broad-leaved trees when entering the stage of arbor-shrub in the west Guangxi area. There are not only evergreen species but also defoliating species in this stage in central Guizhou Province. But there are mainly evergreen species in this stage in east Yunnan Province. The plant species in tree layer is humdrum in human forest, and the plant species in herbosa and shrub layers was effected by jamming.(2) The changing tendency of in different layers of hill closing for forest was not consistent in three typical Karst rocky desertification areas. has respective succession rule in every area. The in herbosa layer was the most in the stage of herbosa of hill closing for forest in west Guangxi, then declined gradually. This diversity index changed unconspicuously from the stage of herbosa-shrub to arbor-shrub, but declined obviously to the last succession stage in this area. In central Guizhou, the diversity in herbosa layer raised firstly, then declined. The species richness was the most in the stage of herbosa-shrub, but simpson and shannon index was the most in that of vine-shrub. The diversity index in herbosa layer changed undeely. In west Guangxi and central Guizhou, the diversity index in shrub, arbo layer and community raised firstly and reached the most in the stage of arbo-shrub, then declined. In east Yunnan, the diversity index in shrub and arbo layer changed undeely, and that in the community raised firstly and reached the most, then declined, but the time when the index reached the most was not consistent.At the beginning of hill closing for forest, the diversity in herbosa layer was greater than that in shrub layer .Then the diversity in shrub raised and exceeded that in herbosa layer finally, but the stage when that appeared was not consistent. was in the stage of vine-shrub in west Guangxi, in the stage of arbo-shrub in central Guizhou and east Yunnan. When arbo appeared, the diversity in shrub layer was the greatest, and that in arbo layer was the least.(3) In central Guizhou, the diversity of plum forest was affected by human disturbance largely. The diversity of every layer and community was the least in beginning fruit stage. when developed after the abundant fruit stage, raised. It reached the most in declined stage. The diversity in herbosa layer of cupressus duclouxiana forest raised from herbosa layer, and reached the most to beginning lignum stage. That in shrub was the least in beginning lignum stage. That of community declined gradually as succession. In east Yunnan, the diversity of armand pine forest in every layer and community raised as succession and reached the most in the beginning lignum stage, then declined gradualy. That in shrub layer and community reached the least in ripe lignum stage. Compared with defoliate- latifoliate forest, the diversity of dendrocalamus latiflorus forest is lower. The diversity in arbo layer and community of bamboo- latifoliate forest can be improved, but that in herbosa and shrub layer was restrained.(4) The effect that hill closing for forest could improve the species diversity was the best, while the lignum forest was the worst. At the beginning of vegetation succession, the species composition and diversity was determined by the land utilization way. The plant species in droping out farmland was primaryly the one year growth herbosa and the diversity of it is high. The plant species in afforestation in the wild is perennial herbosa, preponderant species was obvious, and the diversity was worse. In metaphase stage, the difference of species diversity of all models came out. The diversity of hill closing for forest was the hightest in all models from metaphase stage to the last succession stage. The diversity in shrub layer and community of lignum forest was higher than that of fruit tree forest, while it was contrary in herbosa. The diversity of agroforest model was the lowest in all models. In the last stage, the diversity in all layers and community of lignum forest declined, and it became the model that the diversity is the lowest. That of fruit tree forest raised, and it became the human forest model that the diversity was the highest.(5) Hill closing for forest could improve the physical and chemic characteristics of soil obviously. At the beginning of hill closing for forest, soil hardened in a short-term. After the herbosa-shrub stage, the physical character improved, the volume weight decreased and the air permeability increased gradualy. In the process of vegetation succession, the soil pH value reduced unceasingly, and the soil became alkalescence from acidic except east Yunnan. The quantity of OM and N in soil was the lowest in herbosa-shrub stage, then increased. That in west Guangxi and east Yunnan achieved the highest in the last stage of succession, but that in central Guizhou achieved the highest in arbo-shrub stage. In the vegetation succession, the quantity of P and K had different rule of movement. The quantity of P in soil in west Guangxi decreased from the beginning to metaphase stage fleetly, then rebounded little. The quantity of available K changed little, but the quantity of total K decreased ceaselessly in forepart, and became steady in metaphase. In central Guizhou, the quantity of P was the least in herbosa-shrub stage, then increased gradualy. The available K increased ceaselessly in the whole course of succession, but that of total K was contrary. In east Yunnan, the quantity of P and available K was the least in herbosa-shrub stage, then increased gradualy. The total K fluctuated greatly. The quantity of OM and N moved conformably in the three experimental point, but the rule of movement about the quantity of P and K was different obviously.(6) The model of plum forest can not improve the volume weight and air permeability. The soil became acidic from alkalescence in the course of plum growth. The plum required large numbers of OM, N and P from the stage of springwood to rich fruit forest, while the requirement decreased after the recessionary stage. In the whole course of growth, the plum require litter K. So, the K in soil got together ceaselessly. The cumulation of Ca, Mg and Fe in soil was greater than loss.The volume weight and air permeability in soil in cupressus duclouxiana forest did not change before the stage of beginning lignum. Then the volume weight decreased and air permeability increased. The same as hill closing for forest, the soil in cupressus duclouxiana forest became alkalescence from acidic and the air porosity rised. Before the stage of beginning lignum, the growth of cupressus duclouxiana required large numbers of OM, N and P .Then, the cumulation was greater than expenditure. the growth of cupressus duclouxiana required liter K, so it cumulated ceaselessly. The loss of Ca and Mg is great.The armand pinus forest can not improve the physical and chemic character of soil obviously. The volume weight was the least, and the air permeability, quantity of OM and N was the most. Then, the soil hardened more. The quantity of OM and N decreased gradualy because of not supplement. The quantity of P and K cumulated, because it was consumed few. The quantity of Ca and Mg was the most in the stage of ripe forest.In the Karst area in west Guangxi, the physical and chemic character of soil in defoliating-latifoliate forest was the best, agroforest took second place, while that in dendrocalamus latiflorus was the best. Bamboo- latifoliate forest could improve the character of soil, but it was not as good as defoliating- latifoliate forest.
In recent years, the studies on ecosystem services are taken into account, which is the front topic of science study. This text regards the remote sensing and the geographic information system as the main technological means. Unifying the land utilization and the vegetation situation of the region, the coastal wetland area of Liaoning Province is divided into 11 kinds of landscapes type. They are sea wetlands, river or drainage or ditch, beach land, forest land, bush or grass, swampy ground, reservoir or pond, paddyfield, salt field and aquiculture area.analyzes dynamic evolution of various landscape types from 1990 to 2005.Through the inquiry on the wetland of coastal area in Liaoning Province in 2005, based on the techniques of remote sensing, GIS(Geographical Information Systems) technology, with the Eco-economic and Resources-environmental theory, this article evaluates wetland ecosystem service function and its value with various methods, for example market value method, travel cost method and shadow project method etc. The conclusion can be drawn that the total assets value of the wetland resources is 1157.22×10~8 RMB in wetland of Liaoning, is 19.45% of total GDP of in 2005. Of which, about 516.33×10~8 RMB to water storing value, about 414.03×10~8 RMB to tourism value, about 364.88×10~8 RMB is ascribed to the value of main plants and animals, about 202.95×10~8 RMB to revetment, about 47.54×10~8 RMB to service function value, about6.90×10~8 RMB to water purification value, about 2.71×10~8 RMB to CO2 fixing, O2 releasing, about 1.88×10~8 RMB to habitat value. Their respective proportions are 33.16%, 26.59%, 23.27%, 13.03%, 3.05%, 0.44%, 0.17% and 0.12%.Finally, analyzes ecosystem service function of the coastal wetland area in Liaoning Province and its value. According to population, , , resources and its present environment situation of Liaoning Province, it maintains balance of the wetland ecosystem, and protects wetland function and the biological multiplicity, and improves water environment. It takes resources sustainable as the starting point, persisting the policy of comprehensive protection, prior ecology, prominent key, reasonable use, continues developing, providing the science reference for the coastal wetland area in Liaoning Province in land development plan.
Several industrial wastewater streams may containsuch as Cr, Cu, Pb, Zn, Ni, etc. including the waste liquids generated by metal finishing or the mineral processing industries. The toxic metals, probably existing in high concentrations must be effectively treated/removed from the wastewaters. If the wastewater were discharge into the sewerage system may effect negatively the subsequent biological wastewater treatment.Previous works also mentioned that the synthetic had higher efficiency in the removal of (Pb2+, Cd2+, Cu2+, Hg2+) than HAP. In this study present a new process for synthesis by using eggshell waste, historically a waste byproduct from the food products industry, for decrease the cost of sorbent. Carbonate hydroxylapatite samples were prepared as follows: the pretreated （washed and dried） eggshell wsate was ground and sieved into powder （30 mesh） at first. Then, the eggshell was added to H3PO4 aqueous in molar ratio 1:1, kept at 3040℃for 2 to 3 hours, under pH 13. Insoluble matter was separated and removed by filtration. Subsequently, Ca（OH）2 was added into the solution, kept at 5060℃for 24 h, adjusting pH 912 by NaOH, The adjusting pH to 7 by NH4Cl. At last, the suspension was dried and ground into powder manually （30 mesh） to get the sample. The sample was studied by Scan Electron Microscope and Energy Disperse Spectroscopy.The adsorption of heavy metals with was divided into two parts, including the adsorption to single heavy metal and the multi- metals at the same time. The effect of various parameters on adsorption process such as initial concentration of metal ions, solution pH, contact time, amount of CHAP and temperature were studied to optimize the conditions for maximum adsorption. The sorption isotherm, the dynamic and thermodynamic of process were study. Then the sample after the adsorption of heavy metals was studied by Scan Electron Microscope and Energy Disperse Spectroscopy.At last the desorption was studied with NaCl（0.2mol/L）, NaNO3（0.2mol/L）, HAC（pH=3.93）, HAC（pH=4.93）, CaCl2（0.05mol/L）, CaCl2（0.1mol/L） and ultrasonic to the sample of CHAP after adsorption the Zn2+.The present study showed that the CHAP was effective in removing Cd2+, Zn2+, and Ni2+ from aqueous solutions. The results showed that the removal efficiency of Cd2+ and Zn2+ by CHAP could reach 93% and 98.67% respectively, when the initial Cd2+ concentration 80mg/L and Zn2+ concentrarion 100mg/L and the solid/liquid ratio was 2.5g/L, and when solution pH and contact time was 6 and 67 and 1h and 45 min, respectively. The equilibrium sorption data for single metal systems at 40℃could be described by the Langmuir and Freundlich isotherm models. At low pH the main mechanism between CHAP and metal ions are ion-exchange and surface adsorption. Possibly some precipitation of metal could occur at higher pH. The results showed that zinc adsorption on CHAP would be an endothermic process, and might occur more effectively at relatively high temperatures. The results of multi- heavy metals adsorption showed that the capacity adsorption less than single metal, which competitive for the active point. Desorption experiments showed that various extractant reagents were not efficient enough to desorb substantial amount of metal ions from the CHAP. The results obtained show that CHAP has a high affinity to heavy metals. Neddle-shaped minerals were found after adsorption heavy metals.
This article was based on the oil contained wastewater which has launched significant impact on environment and human.The preparation of , cationic flocculant and modified polyaluminum chloride and treatment of oil contained wastewater were illustrated by the method combinding theoretical analysis and experimental verification.Study explained these following facts: the effect of absorption of was better than diatomite; using both two modified agent was better than one and the best ratio was CTMAB∶TMAB=1.0∶2 .0; the dosage of modifier had effects on absorption; and the optimal conditions of absorption were pH=7～8, the best time of absorption 50min; Then the removing rate of oil from water using modified diatomite was 75.45%. And the optimal technics ready for were concluded, includes: the reaction of ethanediamine and CS2 in alkaline solution with mass ratio of 12.00:28.88:16.00, the reaction temperature of 10～15℃,20～28℃, the stirring time of 90 min with speed of 100r/min, 10ml alkali salt and little ethanol and aether. Then the removing rate of oil was 85.43% by using of PDTC with 10ml. Moreover, the optimal conditions of preparation for were pH=5～6,the concentration of SiO2=2.5%,A1/Si=1.0。The operational parameters for wastewater treatment were investigated.The best operational parameters were found that dosage was 125mg/L, pH=8,stirring time was 20min,stirring temperature was 50℃. The experiment for application showed that PASC has better flocculation efficiency in wastewater treatment than PAC.Just because of the potential advantage of aiming at treating complicated , to get the optimal water treatment technological process were necessary through studying different ratio of these three flocculant, that is, at ordinary temperatures, fast stirring for 3～4min(100～120r/min)and slow stirring for 14～16min(60r/min)in alkaline solution with mass ratio of modified diatomite: PDTC: modified polyaluminum chloride= 2.5g/L :0.025g/L:0.025g/L, and the removing rate of oil can get over 92%, and 91.1% when treating polluted water of refinery in Yan’ an, furthermore, the removing rate of COD and turbidity were 68.3%, 98% and 70%, 85.7% accordingly when treating coal-washing wastewater and paper-making wastewater. In all, we can conclude that this kind of flocculant has good function in treating not only , but other wastewater with high degree of turbidity.At last, mechanism of flocculant and microcosmic rules of mechanism were analyzed.
Study on the Treatment of Synthetic Detergent Wastewater Using the Technology of Anaerobic Biofilter and Biological Contact Oxidation Process
The composition ofwhich was produced by Xi’an Nanfeng Daily Chemical Plant, is very complicated, and the content of organic matter is high. The wastewater contains a lot of linear alkyl benzene sulfonate ( ), which is hard to be biodegradable, and the color is tan, partial alkaline, multi-bubble. has a certain toxicity, and has a greater impact for the the water environment. Furthermore, also has a strong foaming and emulsifying properties, so the treatment is very diffcult. As for the properties of , investigations had been performed on biodegradability of synthetic detergent firstly , and emphases had been put on experimental analysis on Anaerobic Biofilter . During the proess of hydrolytie acidifieation, big molecules had been divided into small molecules , and unbiogradable substances were also converted into biodegradable substances in the wastewater , so as to lay the foundation for the aerobic biological treatment of the follow-up. On this basis, deside to adopt the two-stage membrane model of AF anaerobic biological filter – aerobic biological contact oxidation Joint Process to treat wastewater.The two-stage membrane experiment showed that AF operated in the conditions of HRT=24h and temperature 32±2℃, the macromolecules organic pollutants had been degraded effectively ,and the removal rate of LAS and COD can be up to 50% and 30% respectively. The ration of BOD/COD had been increased from 0.3 to 0.5 around, and the biodegradability of wastewater improved greatly. Aerobic biofilter operated in the conditions of LAS<40mg/L, HRT=12h and DO=4-5mg/L, the final effluent of comprehensive biochemical treatment is COD<40mg/L and LAS<5mg/L, reaching I-class criteria specified in Integrated Wastewater Discharge Standard(GB 8978-1996). In practice, the national policy of protecting the ecology and the environment, which as the strategy of sustainable development had been executed well.The two-stage membrane joint technology provided a reasonable and reliable technology programmes and technical operating parameters for industrial application, and deduced the matrix degradation dynamic model of aerobic biological contact oxidation treatment LAS: 0.72( 0.3288) K S=37.69mg/L, and the coefficient R2=0.9879。
As the industrial structure is irrational,extensive mode of economic growth there is no fundamental change by now,environmental pollution situation is deteriorating.Therefore strengthenof pollutants is a very urgent and important task in the current and future environmental prevention.Pollutant emissions forecast is an important component of of pollutants.Given the situation,Zhenhai District is taken as case.The total emissions of pollutants was forecasted and then the pollutants emission was projected in the Zhenhai District during the year 2006-2020 by taking scenario analysis method.And then we developed a scenario under optimize the distribution of programmes and environmental protection measures,so as to provide decision-makers alternative proposals and scientific basis.Firstly,the situation of socio-economic development and geographical features were evaluateed.In particular,we made a system study on environmental situation in Zhenhai District.The major environmental pollutants and source is identified According to Zhenhai District actual situation,the specific method of of pollutants is developed.Based on the ecological function zoning method, the study area is divided into a number of control units.In the control unit level,we set of several scenarios on pollutant emission.Finally,we optimized scenarios by discrete planning approach.Secondly,the economic and industrial output trend is projected by LEAP2008 model in Zhenhai District. for 2010 and 2020 the population was 234,622 and 260,068 people By 2020,industrial output is expected to reach 394.6 billion yuan which is growth of 306.7 percent over 2005.And on this basis,the industrial sources and life source of emissions scenarios are the projected.Life source of pollutants has an increase of 66.9 percent in emissions of COD which grown from 5118 t to 8543 t.On the contrary,the life source of NH3-N rose from 483.5 t to 607.52 t grew only 25.6 percent.The growth rate of COD is faster than the one of NH3-N.Industrial sources of pollutants emissions projections showed that:COD,SO2 and NH3-N pollutant emissions were three different variations of living trends.Emissions of COD has the M-type trend,the minimum 1608.95 t,the highest 3497.56 t.Emissions of SO2 show the trend of gradually decreasing throughout the forecast period.NH3-N emission is the smallest one among three pollutants. increase after declining trend, the largest emissions in 2015,up to 93.59 t.Third,the various scenarios for the programme of the control unit have been optimized by the use of discrete planning method.After repeated set parameters, Economic benefits has been the best to meet At the same time,overall control objectives and requirements of the optimization scenarios is met.Under the scenarios: 2020 the total industrial output value will reach 405.18 billion yuan,up 317.6 percent growth in 2005.Industrial emissions by sources COD,NH3-N and SO2 is 3450 t, 73.48 t,13104.43 t respectively.Finally,a programme in total amount control of pollutants was developed,on the basis of the relevant Zhenhai District policies,regulations and optimization scenarios. Emission of SO2 reduce to the 17,890 t in 2010 from 2005′s 60,270t.Emission of COD calls for a reduction of 15%,which reduce to 4,910 t in 2010,from 5,780 t in 2005.The cost-benefit analysis found that the programme can obtain better economic, and ecological benefits.
Ecosystemis a new theroy that develop in late 80s of 20 century, which derived by the idea of sustainable development. A ecology system contains two abilities: to suffice sober request of human society and to self-sustaining and renovate. Ecosystem is a comprehensive theroy that studies on human activities, society organizations and nature systems. There is only a decade or more after the idea of was put forward. During this time, the study of ecology system often force on explore the concept and substance of , the method and index system to assess , to assess the health status of different types of ecology systems. In the past, the studies usually force on nature ecology system, such as marine ecosystems, forest ecosystems, and also include agro-ecosystems which under human management, whereas less studies on urban ecology system.Urban ecology system counties three subsystems: nature, economic and society. As offers essential ecological services, the level of ecosystem health will finally impact on the level of humanhealth and affect the appropriateness of living Metropolitan area is the core of a city, the level of health of metropolitan area’s ecosystem, will impact on the city’s and economic sustainable development directly. Metropolitan area plays an impotent part in the development of and economic. By take a comprehensive evaluation of metropolitan area of Chongqing we can find out potential risks of the city’s ecosystem and the causes of those problems, and then excogitate a way to adjust the city’s ecosystem. can provide the basis for metropolitan area of Chongqing’s planning, alteration, development and management and make an important sense in lead the development of Chongqing in a logical, harmonious, sustainable way.The layout of this thesis includes six chapters. The introduction part is literature review, as for the emergence of ecosystem health theory, mainly introducing the backgrounds, concepts, contents of study, and assessing methodology and so on. reviews the course of the theory’s study and the hotpots of nowadays, then further discusses about its problem and developing way. The body parts of the thesis introduce the researching methodology and technical way, and construct the evaluating indices system of ecosystem health of metropolitan area of Chongqing by analyze the system by means of (AHP for short) after analyses of the area’s actuality of nature, economic and . Finally, aiming at comprehensively and comparatively analyzing the state of Ecosystem health of metropolitan area of Chongqing from 1997 to 2006(value once every two years). We propose to improve the strategies in environmental management, hope to provide decision-making basis for the Chongqing’s urban construction and sustainable development and provide reference for other cities in ecosystem health assessment. Therefore, the thesis reaches the conclusions as follows:(1) According to the characteristics of urban ecosystem and metropolitan area of Chongqing’s social, economic, environmental and other realities, constructed ecosystem health evaluation index system of metropolitan area of Chongqing. This evaluation index system contends three levels, include 37 indicators of vigor, organization, resilience, maintenance of ecosystem services, human health effects of the system. They fully reflect the connotation of the city’s ecosystem health. Then we set the standard for the reference value by reference the corresponding index value at home and abroad. Formed a system of the city’s ecosystem health assessment methods that including indicators, weight, evaluation criteria.(2) According to the metropolitan area of Chongqing’s ecosystem health comprehensive assessment index system, using AHP, evaluated the ecosystem health of metropolitan area of Chongqing of 1997-2006 (to one year interval). The results show that the ecosystem health of the metropolitan area of Chongqing in was overall upward trend 1997 to 2006, but there are also problems such as uncoordinated development in individual indicators, and the growth rate of different index in subsystems were very different.. Then come to the result that the stress factors of metropolitan area of Chongqing,s ecosystem that limit it’s ecosystem health are: GDP per capita, Green coverage, science and technology spending in , the proportion of tertiary industry in GDP, the number of health professionals per thousand people, the number of College Students per ten thousand people. Furthermore, some infrastructures that effect people’s facilitation of life need to be enhanced.(3)The thesis hopes to provide scientific basis for planning for the development of Chongqing by analysis the state of ecosystem health of metropolitan area of Chongqing. This study prove measures for improving the ecological health of the metropolitan area of Chongqing, they are: promoting the urbanization reasonable, and regulate urban agriculture; softening of the economic structure, increase the technology content of industries; control population growth, building a good urban living environment; adhere the four projects of Blue Sky, Clear Water, Quite and Green, protect urban green space; strengthen urban management, conduct functions and organizations building of urban, make it orderly.
Electrocatalytic Reductive Dechlorination of Polychlorinated Biphenyls by Palladized Aligned Carbon Nanotubes Electrode
The electroreduction process has caused world-wide interest because of its high dechlorination efficicency,simple operation,and environmentally friendly property.In this dissertation,the palladized aligned（Pd/CNTs/Ti）electrode is fabricated for electrocatalytic dechlorination of polychlorinated biphenyls（PCBs）.Well aligned are prepared by chemical vapor deposition on the Ti substrate and purified.The effects of deposited temperature,ferrocene concentration and deposited time on the morphology of CNTs are investigated.The scanning electron microscopy（SEM）and transmission electron microscopy（TEM）indicate that the well aligned CNTs have been successfully grow on the Ti surface,and the preparation conductions of deposited temperature,ferrocene concentration and deposited time are 800℃,24 mg/mL and 5 min,respectively.The external diameter of CNTs is about 80 nm while the inner is about 15 nm.After purification,the morphology of CNTs has not been destructed and the properties of the CNTs electrode could be improved.The constant current electrodeposition is used to load Pd onto the surface of the CNTs to synthesize the Pd/CNTs/Ti electrode.The effect of current density and depoited time on the morphology and property of the electrode are investigated.The TEM image indicates that Pd particles,whose average diameters are 10 nm,are dispersed uniformly on the surface of CNTs. The preparation conductions of current density and deposited time are 1.0 mA/cm2 and 10 min,respectively.The X-ray diffraction（XRD）and energy-dispersive X-ray（EDX）have proven that the Pd has been loaded on the CNTs indeed.The excellent electrochemical property of the Pd/CNTs/Ti electrode is shown by the analysis of cyclic voltammetry.The electrocatalytic reductive dechlorination of the 2,4,5-trichlorobiphenyl is carried out using the palladized aligned carbon nanotubes.The effect of synthesized conditions of electrode,supporting electrolyte,working voltage and initial concentration of PCB29 on the dechlorinated degradation efficiencies are investigated.After 6 hours electrolysis with Pd/CNTs/Ti electrode,the degradation efficiency of PCB29 was up to 90%while the supporting electrolyte and working voltage were 0.05 mol/L H2SO4 and -1.0V,respectively. The performance of the Pd/CNTs/Ti electrode is better than the pallidum-loaded graphite and Ti electrodes.The monochlorobiphenyl,dichlorobiphenyl and biphenyl are detected by the qualitative analysis of the dechlorinated production.Meanwhile,the increasing of the concentration of chloride ion has confirmed in the process of electrocatalytic reductive dechlorination.In a word,the optimal conditions for the synthesis of Pd/CNTs/Ti electrode and electrocatalytic reductive dechlorination of PCB29 are investigated,and the dechlorinated productions are qualitatively analysis in this dissertation.The results will provide the theoretical and experimental basis for the application of electrocatalytic reduction using carbon electrodes in treatment of wastewater containing polychlorinated biphenyls.