[Driving Factors Analyze of Phytoplankton Community by Comparison of Population and Functional Groups and Water Quality Evaluation in Dongting Lake].

Phytoplankton is the most important component of water ecosystems, which could indicate the state of the water environment owing to its sensitivity to water environment variation. However, its response to the environment is influenced by classification methods. To understand the phytoplankton population(phyla and genera) and functional groups(FG) for driving response characteristics and applicability to the environment in Dongting Lake, a total of four samples were collected from the lake from March to December 2019, and the distribution characteristics of the phytoplankton population and functional groups and their responses to environmental factors were compared and analyzed. Meanwhile, the applicability of the TLI index, Shannon-Wiener index, and Q index was compared in Dongting Lake. The results showed that a total of 61 genera belonging to six phyla of phytoplankton were detected in Dongting Lake, which could be divided into 23 functional groups and nine dominant functional groups. The succession trend of functional groups was P/MP/D(March)→MP/P/J(June)→MP/H1(September)→Y/P/MP(December). The results of hierarchical segmentation showed that the population distribution and change in phytoplankton were driven by environmental factors more than the area in Dongting Lake. The main environmental factors affecting phytoplankton population and functional groups were water temperature(WT), permanganate index, dissolved oxygen(DO), conductivity(Cond), water level(WL), and total phosphorus(TP). RDA analysis showed that phytoplankton functional groups identified phytoplankton response to environmental factors better than phytoplankton population. It was shown that using the Q index to evaluate water quality had better applicability in Dongting Lake.

Coagulation-flocculation: a potential application for mosquito Larval Source Management (LSM).

Larval mosquitoes have a more limited home range and lower resistance to adverse environment than adults, thus can be ideal targets for vector control in some cases. Coagulation-flocculation technology, which could be used for water treatment in breeding sites of several vector mosquito species, can significantly change both the distribution of organic particles and surface sediment characteristics in water environment. The aim of this study was to explore the effect, principle and possibility of using coagulation-flocculation technology in immature mosquitoes killing. In this study, dechlorinated water was treated with Poly Aluminum Chloride (PACl, sewage treatment using), and we observed the impacts of PACl treatment on the development and survival of immature Culex pipiens pallens mosquitoes. When exposed to PACl treatment, physical effect is believed to be a main reason of coagulation-flocculation caused high larvae mortality: Ⅰ) alum floc layer increases the difficulty of larvae foraging, leads larvae starving to death; (Ⅱ) the little floc particles could attach to the lateral hair of larvae, which impede floatation process and then surface respiration by larval mosquitoes. The alum floc layer had a good killing effect on the mosquito larvae, presented the half lethal time (LT50) of 2d, the 90% lethal time (LT90) of 8.7±7.3 ∼ 14±4.5 d, and the pupation rate of 0 ∼ (6.5±0.5)%, respectively. Our results indicates alum floc, produced by PACl coagulation-flocculation, was shown to be highly active against 1st∼2nd instar larvae, the high mortality rate of immature mosquitoes as a result of physical effect. The observations suggest that coagulation-flocculation technology offers a novel potential approach to a sustainable and low-impact mosquito control method.

[Research on Remediation of Heavy Metals in Sediment with Lotus and Water Lily].

The aquatic landscape plants lotus and water lily were selected to repair the heavy metal in black odorous river sediments. With ICP-AES inductively coupled full spectrum of direct reading plasma emission spectrometry, the total and forms of content of heavy metals Cd, Cr, Cu, Ni, Pb in sediment and plants, the distribution of heavy metals in plants to were determined .The results showed that the average removal rate of the lotus in terms of the removal of heavy metals in the sediments was 20.42% while that of water lily was 18.23%; after lotus and water lilies were planted, the forms of content of heavy metals in sediments were decreased, the phytoremediation of main forms of Cr, Pb, Ni in sediments were theresidual state; the main forms of Cd, Cu were extractable. The distribution of Cu, Ni among the water lilies was stem

[Optical signatures of chromophoric dissolved organic matter in water body of Tien Lake].

The water samples of the Tien Lake were collected for the three-dimensional fluorescence spectrum detected. And parallel factor analysis (PARAFAC) and principal component analysis (PCA) were used for the spectra analyzing to know the main factor and relative contribution of the chromophoric dissolved organic matter (CDOM). PARAFAC decomposed CDOM into four components, the humic-like: C1 (240, 415), C3 (265, 525), C4 (255, 505) and the protein-like: C2(230/280, 330). The fluorescence intensity of CDOM components was high in north and estuary of the lake, but low in the other region. All the four components show significant positive correlations (p < 0.01), this result means they may have the same sources. Principal component analysis shows that these four components of the Tien Lake are all from terrestrial organic matter, meanwhile its DTN, DTP, DON may also come with the terrestrial substance. These components of Tien Lake can well be connected with dissolved nutrient salts by nonlinear multiple regression, which means we can use the three-dimensional fluorescence spectrum results of CDOM to indicate the eutrophication degree of Tien Lake.

Molecular phylogenetic analysis of dominant microbial populations in aged refuse.

The phylogenetic analysis of dominant microbial populations in 8-year-old refuse samples was done in terms of the whole Bacterial and Archaeal domains. The results indicated that the Bacterial 16S rRNA genes sequences from the aged refuse were largely affiliated with the genus Bacillus, and that more than 60 % of the Archaeal sequences were closely related to the methanogenic archaeon. Some inferentially identified extremophilic organisms, particularly alkaliphiles and/or halophiles, were noted to be present in the aged refuse. Moreover, molecular evidence for the occurrence of ammonia-oxidizing Archaea in aged refuse was reported, which opens up avenues for elucidating its role in ammonia transformation in landfill systems. It seems reasonable to assume that the highly complex environment within the landfill systems may select for microbial populations with versatile metabolism and strong adaptation. These findings underline the need for further biochemical and ecological study of these organisms in aged refuse.

Seasonal variations and aeration effects on water quality improvements and physiological responses of Nymphaea tetragona Georgi.

Seasonal variations and aeration effects on water quality improvements and the physiological responses of Nymphaea tetragona Georgi were investigated with mesocosm experiments. Plants were hydroponically cultivated in six purifying tanks (aerated, non-aerated) and the characteristics of the plants were measured. Water quality improvements in purifying tanks were evaluated by comparing to the control tanks. The results showed that continuous aeration affected the plant morphology and physiology. The lengths of the roots, petioles and leaf limbs in aeration conditions were shorter than in non-aeration conditions. Chlorophyll and soluble protein contents of the leaf limbs in aerated tanks decreased, while peroxidase and catalase activities of roots tissues increased. In spring and summer, effects of aeration on the plants were less than in autumn. Total nitrogen (TN) and ammonia nitrogen (NH4(+)-N) in aerated tanks were lower than in non-aerated tanks, while total phosphorus (TP) and dissolved phosphorus (DP) increased in spring and summer. In autumn, effects of aeration on the plants became more significant. TN, NH4(+)-N, TP and DP became higher in aerated tanks than in non-aerated tanks in autumn. This work provided evidences for regulating aeration techniques based on seasonal variations of the plant physiology in restoring polluted stagnant water.

[Spatial distribution and contamination assessments of heavy metals in sediments of Wenzhou River network].

In order to investigate the spatial distribution pattern and degree of heavy metal pollution in river network sediments of Wenzhou, 29 sediment samples were collected, and using atomic fluorescence spectrometry (AFS) and inductively coupled plasma-optical emission spectrometry (ICP-OES) heavy metal concentration in the samples were analyzed. The Kriging interpolation map reflected the spatial distribution of heavy metal. Comprehensive geo-accumulation index based on the Nemerow index method was established to assess the pollution degree. Pearson correlation analysis method and principal component analysis method were employed in sources analysis. Results show that heavy metal concentration varies significantly at different sites. The area with highest Cd and Zn concentrations is the centralized urban and industrial area of the main stream of this river network, while the highest concentrations of As, Pb, Hg, Cu, Ni and Cr were found to be in machinery industrial park. Sediments are contaminated by Hg, Cd, Cu, Zn, Ni and Cr. The order of degree of contamination is as follows: machinery industrial park > urban areas of the main stream > Sanyang Wetland>outskirt and rural area > drinking water source area. Hg, Cd, Cu, Zn, Ni and Cr have similar pollution sources which are mainly anthropogenic sources.

[Influence of disturbance intensity on nitrogen, phosphorus and permanganate index release of Potamogeton crispus during soaking in water].

Influence of various disturbance intensities on nitrogen, phosphorus and permanganate index (PI) release of Potamogeton crispus were investigated during the plant soaking in water, and the plant materials were collected in an urban lake of Beijing. Results showed that more rapid release of TP and PI from Potamogeton crispus were caused by disturbance, NH4(+) -N and TN in water were significantly increased (ANOVA, p < 0.05) under the condition of high disturbance (120 r/min) for 240 h. However, PI and TP were significantly decreased (ANOVA, p < 0.05) after 240 h disturbance in all treatments. When the release equilibrium of 2.13 g dry mass Potamogeton crispus in one liter of water was reached, the PI, TN, and TP released from unit mass Potamogeton crispus were 35, 5.1 and 4.1 mg x g(-1), respectively. The release ratio of TP from Potamogeton crispus was the highest, while the release ratio of PI was the lowest. The simulated experiment results showed that the highest pollution load to water released from Potamogeton crispus was the TP among the three nutrients. Phosphorus is one of the key factors which causing water eutrophication in lake, thus after submerged plants declining in lake, the field research of phosphorus release and migration from submerged plants into water is the focus of future research work.

[Exploration of relationships between phytoplankton and related environmental factors in the Daning River during sensitive period of algal blooms].

To elucidate relationships between phytoplankton and related environmental factors, phytoplankton and environmental parameters of water quality in the Daning River were conducted using multivariate statistical analysis. Most of the investigated physico chemical parameters [water temperature, total nitrogen, nitrate-N (NO3(-) -N), pH and dissolved oxygen concentration (DO)] in Daning River are significantly different among those sampling sites (ANOVA, p < 0.05). The results indicate that the Daning River has a comparatively high spatial and temporal heterogeneity in the phytoplankton community composition (ANOVA, p < 0.05). The maximum cell density was recorded in Dachang and the minimum density was found at Wuxia-kou sites. Multi-algal species blooms were observed in the same time and place with the maximum density appeared. Correlation analysis was performed to illuminate the relationships between algae density and environmental variables, TN (r = - 0.789, p < 0.05), NO3(-) -N (r = - 0.825, p < 0.05) and NO2(-) -N (r = -0.803, p < 0.05) were negatively correlated with algae density. The results indicate that nitrogen soluble nutrients are key regulatory factors for phytoplankton abundance. The results of redundancy analysis (RDA) indicate that main soluble nutrients (TN, TP, NO3(-)-N and NO2(-)-N), suspended substance (SS) and transparency contributed significantly to phytoplankton community composition. Phytoplankton growth could enhance the pH value. The environmental characterizations and sample sites adjacency contributed significantly to phytoplankton community composition.

[TTC-ETS activity monitoring of A2/O process for combined sewage treatment].

The influences of variations of temperature and F/M on the TTC-ETS activity have been experimentally studied. The correlation between TTC-ETS activity and COD degradation was also analyzed. Comparing TTC-ETS activities with physical and chemical indexes when high C/N ratio impacted A2/O process, the advantages and disadvantages of using TTC-ETS activity to characterize the status of A2/O process were illustrated. The results showed that both temperature and F/M were positively correlated with TTC-ETS activity. TC-ETS activity was in the range of 13.2-48.3 mg/(g x h) and the maximum value was 60 mg/(g x h) which had a significant relationship with COD removal rate. In this system, abnormal state was pre-warned by TTC-ETS activity. The highest removal rate of COD appeared when TTC-ETS activity was 41.0 mg/(g x h).

[Systematic investigation into winter and spring algal blooms in Daning River of Three Gorges Reservoir].

According to the survey conducted from winter and spring algal blooms, the changes of water quality and characteristics of Daning River of Three Gorges Reservoir (TGR) were studied. The results suggested that during the period of winter algal blooms centered on Tangjia bay in Daning river, chlorophyll a (Chl-a) had a wide range (the rates of (Chl-a)max and (Chl-a)min is 260). The contents of total nitrogen (TN), total phosphorus (TP) and potassium permanganate index were at very high levels because of bioaccumulation from algal blooms, but the values of dissolved oxygen (DO) and pH were very low. During winter algal blooms fastigium poor algae were observed accounting for 2 phylum 4 species, dominant species are Microcystis aeruginosa and Microcystis flos-aquae, the maximum value of algal density was 3.15 x 10(7) cells/L, and the correlation weighted nutrition state index was 80, which indicated water body was at high eutrophication level. However the spring algal blooms belonged to whole watershed outbreak, the values of Chl-a, TN, TP and potassium permanganate index became all markedly high with outbreak of algal blooms. There were 5 phylum 44 species algae being observed during spring algal blooms fastigium, different sections observed different dominant species and algal density values. The correlation weighted nutrition state index showed water of Dongping bar and Baishui River sections was at slight eutrophication level. During winter algal blooms there were significantly positive correlations between Chl-a and TN, TP, potassium permanganate index, water temperature, between pH and SD. Significantly negative correlations were observed between Chl-a and DO, SD, between pH and TN, TP, potassium permanganate index. In spring algal blooms significantly positive correlations were observed between Chi-a and TP, potassium permanganate index, DO, pH, between pH and Chla, TP, potassium permanganate index, DO, air temperature. Significantly negative correlations were observed between Chl-a and SD, between pH and SD.

[Diurnal variations in purifying-tanks when use Pontederia cordata treating the Malodorous River water].

Aquatic plants (Ponsederie cordaza) were waked in two purifying-tanks to investigate the effects of illumination intensity and aeration on diurnal variations of Chla, SP, POD of Ponsederia cordaza and pH, DO, COD, NH4+ -N, TP of water from purifying-tanks when treating the malodorous river water at seven different times, another blank purifying-tank was set as a control. Comparative studies and correlation analysis of these different indicators were carried out to improve the plants working efficiency and provide scientific basis for optimal operation of plant purifying-tanks. Results showed that all indicators affected by changes of light, TP shows best correlation coefficient Cr = 0.93, p < 0.01) of physicochemical indicators and SP behaves best correlation coefficient Cr = 0.91 , p < 0.01) of plant physiology indicators in non-aeration purifying-tank;aeration is necessary as diurnal average of DO shows an increase of 0.13 mg/L by treatment of plant meanwhile 1.8 mg/L by plant with aeration,purifying-tanks with aeration got 7.1%, 6.3% higher removing rates of COD, NH4+ -N and 38% less TP removing rate than non-aeration plant purifying-tanks (p < 0.01); with aeration treatment, significant reduction of Chla, SP content (p < 0.05) and increase of POD activity (p < 0.05) observed in plants; the changes of illumination intensity and aeration can significantly affect physiological characteristics of plants and should be considered carefully and need further study when treating malodorous river water by plant purifying-tanks.

[Analysis of algal blooms in Da-Ning River of Three Gorges Reservoir].

According to the survey conducted from Apr. to Jun. 2007 and from Apr. to May. 2008, the changes of water quality, forms and distributions of nutrient salts and characters of algal blooms in Da-ning River of Three Gorges Reservoir (TGR) were studied. The results indicated that the concentrations of nitrogen and phosphorus nutrient were abundant during sensitive period of algal blooms in Da-ning River. Total nitrogen (TN) and total phosphorus (TP) values are 0.84-3.21 mg/L and 0.011-0.531 mg/L respectively, and the nutrients concentrations become high gradually from upstream to downstream. Total dissolved nitrogen (TDN) is the major form of TN accounting for 84%, and total dissolved phosphorus (TDP) is dominant (TDP/TP = 60%). Algal blooms bring phosphorus nutrient bio-concentration. The rates of TN and TP are all in excess of 16, which show eutrophication is limited by phosphorus. Potassium permanganate index and dissolved oxygen (DO) are at low levels and change stably. But chlorophyll a (Chl-a) becomes frequently, the value is 1.41-219.04 mg x m(-3). Significant positive correlations are all observed by correlation analysis between Chl-a and the main parameters (r(Chla-TP) = 0.453, r(Chla-potassium permanganate index) = 0.641, r(Chla-DO) = 0.584, r(Chla-pH) = 0.409, p < 0.01), but significant negative correlations are observed between Chl-a and Secchi depth (SD) (r(Chla-SD) = - 0.392, p < 0.01). The pH is fluctuated by multiparameter esp. in algal blooms. Widespread algae are observed by microscope during sensitive period of algal blooms in Da-ning River accounting for 8 phylum 82 genus 124 species, which Bacillariophyta and Chlorophyta are dominant, and then Cyanophyta and Pyrrophyta. Three whole watershed algal blooms break out in Da-ning River during the period, and the highest values of algal density are 14-1 427 times as many as the normal values. The dominant species of algal blooms are mostly involved with O. borgei, C. microporum, Chlorococcum humicola, P. morum and C. vulgaris of Chlorophyta; P. pleuronectes and T. oblonga of Euglenophyta; Cyclotella, Stephanodiscus astraea and Navicula of Bacillariophyta; P. elpatiewskyi of Pyrrophyta. Multi-algal species blooms are observed in the same time and place, and there are few algae in the estuary of Da-ning River to Changjiang River.

[Analysis of phosphorus distribution characters and their sources of the major input rivers of Three Gorges Reservoir].

The seasonal characters of the water flux and suspended substance, phosphorus in the water of input rivers of Three Gorges Reservoir (TGR) were discussed, and the their distributions among three major input rivers (Changjiang river, Jialingjiang river and Wujiang river) were studied, according to the survey conducted from Jan. 2004 to Dec. 2005. The results indicate that those parameters' seasonal changes are obvious. The flux and suspended substance in abundant water period are more higher than them in low water period, which displays suspended substance origins from bedload and that the water and soil severely lose in drainage areas of three input rivers. In the three monitor sections of input rivers of TGR, the average contents per year of total phosphorus are about 0.12-0.29 mg/L, which exceeds the 1970s level of the three input rivers. Most of total phosphate is total solid phosphate (TPP) exceeding 75% of them. TP and TPP have both distinct positive correlation with the flux and suspended substance in water of input rivers of TGR, and TPP and TP have also the same correlation, which means that phosphate pollution in the input rivers of TGR comes from bedload. The nonpoint source pollution has had far-reaching influence upon phosphate pollution. Nitrogen and phosphate are not the major limiting factor of the nutritious salts in the input rivers of TGR. The rate of between nitrogen and phosphate (N/P) is in higher level (above 30), that is phosphate first will reach lower level and maybe become the limiting factor of the nutritious salts in the input rivers of TGR.

[Evaluation of the damaging effect of dyestuff on Phanerochaete chrysosporium with amplified fragment length polymorphism (AFLP) analysis].

The AFLP analysis was carried out in order to evaluate the DNA damaging effects of dyestuff of different concentrations on Phanerochaete chrysosporium. The DNA similarity and UPGMA cluster analysis were conducted to determine the relationships between the concentrations of dyestuff and DNA damaging effects. The results showed that the AFLP analysis could reflect the polymorphisms of DNA well, and the primer pairs E-AAC/M-CAA could give more amplified DNA fragments than others primers. From the DNA maps of best primer pairs, 35 clear and stable DNA bands were observed, including 12 polymorphous bands which were accounted for 34.3% diversity. It was indicated from the DNA similarity and UPGMA cluster analysis that DNA polymorphisms correlated with dyestuffs concentrations well. If the concentration of dyestuff was not higher than 50 mg/L, the damaging effect on DNA was finite. If the concentrations of dyestuff were up to 300 mg/L, the DNA of Phanerochaete chrysosporium would have been injured greatly, and would have been bankrupted in its intrinsic function.

[Analysis of nitrogen distribution characters and their sources of the major input rivers of Three Gorges Reservoir].

According to the survey conducted from Jan. 2004 to Dec. 2005, the seasonal characters of nitrogen in the water of input rivers of Three Gorges Reservoir (TGR) were discussed, and the forms and distributions of nitrogen among three major input rivers (Changjiang river, Jialingjiang river and Wujiang river) were studied. The results indicate that some primary hydrologic values of input rivers have seasonal characters, and they are in the danger range, which might bring algal bloom. The average contents per year of total nitrogen are 1.55-2.15 mg/L in the three monitor sections of input rivers of TGR, and Wulong monitor section is more severe than the others. The contents of total nitrogen in abundant water period are much higher than them in low water period, which displays the nonpoint source pollution has far-reaching influence upon total nitrogen. The total dissolved inorganic nitrogen (DIN) is the major form of total nitrogen and further nitrate nitrogen (NO3(-)-N) is dominant accounting for 70% or more of DIN. Ammoniacal nitrogen is the uppermost input form of nitrogen pollution of input rivers of TGR. Ammoniacal nitrogen was oxidated to nitroso-nitrogen, and then it was oxidated to nitrate nitrogen using up a lot of dissolved oxygen of water. Nitrate nitrogen sources include agricultural runoff, city pollution water, city runoff and slow-releasing from submersed soil, whenas nitrogen-ammonia (NH4(+)-N) origins are city pollution water, industrial pollution water, and a little source of living garbage and bilgewater.

[Research of aeration with bio-film technology to treat urban landscape water].

Research of the aeration with bio-film technology was carried out to treat scenic water of a sanatorium in Beijing. The aim of the research was improving the water habitat by increasing the transparency and reducing the concentration of N and P. The equipments were set in a 5,000 m2 water area, which combined the plug flow jet aerator with the elastic biological filler. The research indicated that the transparency increased from 25 cm to 120 cm by the technology. The removal efficiencies of NH4(+)-N, NO3(-)-N and TP were 86.6% , 90% and 73.3%, but there was only 22.4% for TN. The concentration of DO increased from 4.3 mg/L to 7 mg/L. In a word, the aeration with bio-film technology was an effective measure to improve the water habitat by increasing the transparency.

[Relation analysis of phosphorus removal and BOD5 loading using PHB monitoring in A2/O process].

In a pilot-scale anaerobic-anoxic-oxic experimental system for municipal wastewater treatment, PHB consumption in an oxic tank and PHB production in an anaerobic tank had been monitored overtime, and relations among PHB consumption/production, phosphorus removal/release and BOD5 loading had been analyzed. The results indicated that the consumption of PHB was positively related with phosphorus removal, and about 140 mg PHB consumption could result in 1 mg P removal. In the anaerobic tank, about 1.17 mg P release could result in 100 mg PHB production. The PHB production at the loading of 0.176 g/(g x d) was 4 mg/g MLSS less than that at 0.413 g/(g x d). No significant relevance was observed between PHB and BOD5 removal. The PHB of microorganism synthesizes was increased with the increase of temperature. Compared with the lowest temperature (17.1 degrees C), 20% of the total PHB content was increased at the maximum temperature (33.2 degrees C) in active sludge.

[Experimental study on the processes and mechanism of enhanced denitrification by addition zeolite in wastewater treatment].

Aim to enhance nitrogen removal from wastewater, addition zeolite to aeration tank was preformed. The result showed that addition of zeolite could improve the nitrification/denitrification efficiencies by comparing two phase experiment of 25 mg/L with blank and 25 mg/L with 50 mg/L, and the population of nitrifying bacteria in activated sludge increased obviously. When 25 mg/L zeolite was added into aeration tank, NH4(+) -N and TN removal increased 10% - 13% and 13% respectively, endogenous respiration rate of nitrification increased about 138%, and the population of nitrification bacteria increased about 2.2 folds. But the nitrogen removal and endogenous respiration rate of 50 mg/L enhanced indistinct comparing with 25 mg/L. These results indicated that NH4+ ion-exchange and accumulation to the interior/outer surfaces of zeolite, co-existence of aerobic and anoxic micro-environments were responsible for the enhanced denitrifying function.

[Impact of dissolved oxygen on the activity of anaerobic granular sludges].

The effect of dissolved oxygen (DO) on the methanogenic activity of anaerobic granular sludges introduced into the expanded granular sludge bed (EGSB) reactor was measured in serum flasks. Results show that the specific methanogenic activity (SMA) decreases with DO increases. At 22 degrees C, the SMA drops from 75.9 mL x (g x d)(-1), 91.1 mL x (g x d)(-1) to 47.6 mL x (g x d)(-1), 71.4 mL x (g x d)(-1), respectively as DO increases from 0.00 mg/L to 7.00 mg/L. Higher temperature can weaken this trend and significantly promote SMA. As the control levels of temperature is 28 degrees C, 35 degrees C, the SMA average increases by 54.0%, 114.4% compared with that of the first gas production experiment. The study confirms that the presence of dissolved oxygen in the influent of an EGSB reactor does not constitute any evidently detrimental effect on the performance of anaerobic treatment process. Anaerobic granular sludges are demonstrated high tolerance for dissolved oxygen so that in practice this factor can be neglected.