Water eutrophication has become a worldwide environmental problem in recent years.Once a water body is eutrophicated,it will lose its primary functions and subsequently influence sustainable development of society and...Water eutrophication has become a worldwide environmental problem in recent years.Once a water body is eutrophicated,it will lose its primary functions and subsequently influence sustainable development of society and economy.Therefore,analysis of eutrophication becomes one of the most essential issues at present.With the ability to deal with vague and uncertain information,and express knowledge in a rule form,the rough set theory(RST) has been widely applied in diverse domains.The advantage of RST is that it can compress the rule and remove needless features by reduction inference rule.By this way,the rule gets effectively simplified and inference efficiency gets improved.However,if data amount is relatively big,it could be a process with large calculated amount to search rules by looking up tables.Petri nets(PNs) possesses so powerful parallel reasoning ability that inference result could be obtained rapidly merely by simple matrix manipulation with no need for searching rules by looking up tables.In this work,an integrated RPN model combining RST with PN was used to analyze relations between degrees of water eutrophication level and influence factors in the Pengxi River of Three Gorges Reservoir.It was shown that the RPN model could analyze water eutrophicaion accurately and quickly,and yield decision rules for the decision-makers at water purification plants of the water quality and assist them in making more cost-effective decisions.展开更多
Based on ecological niche theory, Microcystis Aeruginosa(MA) immobilized in the complex of polyvinyl alcohol(PVA)and sodium alginate(SA) crosslinked by CaCl2, was treated as a new kind of special species, and its prop...Based on ecological niche theory, Microcystis Aeruginosa(MA) immobilized in the complex of polyvinyl alcohol(PVA)and sodium alginate(SA) crosslinked by CaCl2, was treated as a new kind of special species, and its properties were investigated.Chlorophyll a was used to characterize the bioactivity of the immobilized MA. Results reveal that the gel beads have mechanical strength and chemical stability even under non-sterile harsh conditions, which may be attributed to the rarely seen structure(including three different layers: dense surface, tubular-shaped divergent structure and honeycomb crystal lattice layer) of the immobilized MA determined by scanning electron microscope(SEM). SEM also displays that more quantity of MA is attached to the inwall after cultivation, which demonstrates that the MA within beads maintains high bioactivity. Removal capacities on phosphorous(P) removal in wastewater in the presence and absence of the BG-11 medium were examined, and the removal ratios are 80.3% and76.7%, respectively, which indicates that the beads without providing ample nutrients still have high capacity of P removal. In addition, control experiment, utilizing polyvinyl alcohol and sodium alginate(PVA-SA) beads without immobilized MA,demonstrates that MA within beads plays the key role in absorbing P.展开更多
Polymeric phosphate ferric sulfate (PPFS),a new improved coagulation reagent,was prepared by polymeric ferric sulfate (PFS),Na2HPO4 and NaOH. The degree of iron polymerisation (Fepol) of PPFS was determined by means o...Polymeric phosphate ferric sulfate (PPFS),a new improved coagulation reagent,was prepared by polymeric ferric sulfate (PFS),Na2HPO4 and NaOH. The degree of iron polymerisation (Fepol) of PPFS was determined by means of the ferron-timed spectroscopy method. Furthermore,the effect of n(P)/n(Fe),alkalization degree,pH value,and PPFS dosage on the removal rate of eutrophic water turbidity and chl-a and ζ-potential of products were also investigated. The experimental results show that the best n(P)/n(Fe) of flocculation effect in stable product of PFFS is 0.3; the best alkalization degree of flocculation effect is 0.2,while the n(P)/n(Fe) is 0.3. Under the neutral and subalkalic (pH value is 7-8) conditions,PPFS achieves the best processing efficiency. PPFS has more excellent turbidity and higher chlorophyl removal rate by studying treatment eutrophic water in comparison with PFS.展开更多
基金Project(2014ZX07104-006)supported by the National Scientific and Technological Major Project of China
文摘Water eutrophication has become a worldwide environmental problem in recent years.Once a water body is eutrophicated,it will lose its primary functions and subsequently influence sustainable development of society and economy.Therefore,analysis of eutrophication becomes one of the most essential issues at present.With the ability to deal with vague and uncertain information,and express knowledge in a rule form,the rough set theory(RST) has been widely applied in diverse domains.The advantage of RST is that it can compress the rule and remove needless features by reduction inference rule.By this way,the rule gets effectively simplified and inference efficiency gets improved.However,if data amount is relatively big,it could be a process with large calculated amount to search rules by looking up tables.Petri nets(PNs) possesses so powerful parallel reasoning ability that inference result could be obtained rapidly merely by simple matrix manipulation with no need for searching rules by looking up tables.In this work,an integrated RPN model combining RST with PN was used to analyze relations between degrees of water eutrophication level and influence factors in the Pengxi River of Three Gorges Reservoir.It was shown that the RPN model could analyze water eutrophicaion accurately and quickly,and yield decision rules for the decision-makers at water purification plants of the water quality and assist them in making more cost-effective decisions.
基金Projects(51178172,51308076)supported by the National Natural Science Foundation of ChinaProject(13JJ4107)supported by Hunan Provincial Natural Science Foundation,ChinaProject(K1207026-31)supported by Changsha Planning Project of Science and Technology,China
文摘Based on ecological niche theory, Microcystis Aeruginosa(MA) immobilized in the complex of polyvinyl alcohol(PVA)and sodium alginate(SA) crosslinked by CaCl2, was treated as a new kind of special species, and its properties were investigated.Chlorophyll a was used to characterize the bioactivity of the immobilized MA. Results reveal that the gel beads have mechanical strength and chemical stability even under non-sterile harsh conditions, which may be attributed to the rarely seen structure(including three different layers: dense surface, tubular-shaped divergent structure and honeycomb crystal lattice layer) of the immobilized MA determined by scanning electron microscope(SEM). SEM also displays that more quantity of MA is attached to the inwall after cultivation, which demonstrates that the MA within beads maintains high bioactivity. Removal capacities on phosphorous(P) removal in wastewater in the presence and absence of the BG-11 medium were examined, and the removal ratios are 80.3% and76.7%, respectively, which indicates that the beads without providing ample nutrients still have high capacity of P removal. In addition, control experiment, utilizing polyvinyl alcohol and sodium alginate(PVA-SA) beads without immobilized MA,demonstrates that MA within beads plays the key role in absorbing P.
基金Project(20777095) supported by the National Natural Science Foundation of ChinaProject(CSTC, 2006AB7055) supported by Chongqing Science and Technology Commission of ChinaProject(708071) supported by the Cultivation Fund of the Key Scientific and Technical Innovation Project,Ministry of Education,China
文摘Polymeric phosphate ferric sulfate (PPFS),a new improved coagulation reagent,was prepared by polymeric ferric sulfate (PFS),Na2HPO4 and NaOH. The degree of iron polymerisation (Fepol) of PPFS was determined by means of the ferron-timed spectroscopy method. Furthermore,the effect of n(P)/n(Fe),alkalization degree,pH value,and PPFS dosage on the removal rate of eutrophic water turbidity and chl-a and ζ-potential of products were also investigated. The experimental results show that the best n(P)/n(Fe) of flocculation effect in stable product of PFFS is 0.3; the best alkalization degree of flocculation effect is 0.2,while the n(P)/n(Fe) is 0.3. Under the neutral and subalkalic (pH value is 7-8) conditions,PPFS achieves the best processing efficiency. PPFS has more excellent turbidity and higher chlorophyl removal rate by studying treatment eutrophic water in comparison with PFS.
