Papers by Keyword: Eutrophication

Abstract: Ascendency theory which is developed by Ulanowicz is an index of activity and organization in living systems and is about to quantify the whole-system status. Being calculated in terms of flows, the ascendency is used to quantify the eutrophication of the ecosystem. However, when network magnitudes and topologies are changed from non-eutrophic to strongly eutrophic, the ascendency which is calculated in terms of flows of simple energy is relatively insensitive to such changes. However, when the flows are measured in terms of eco-exergy, it is more advisable. The ascendancies of two different trophic levels which are non-eutrophic and strongly eutrophic are calculated on simple energy and eco-exergy respectively. The analysis of ascendency about the two different trophic levels also proves that ascendency is more sensitive when based on eco-exergy than on simple energy. The ascendency based on eco-exergy is more appropriate to quantify the ecosystem status.

Abstract: In order to study the remedation technology of eutrophic artificial lake, an integrated restoration technique consisted of aquatic vegetation near lakesides, Effective Microorganisms (EM) , fingerlings and intermittent aeration system was constructed in Guilin City, Guangxi of China. The results indicated that the removal rates of Chemical Oxygen Demand (COD),total nitrogen (TN),total phosphorus (TP),suspended substance (SS) and turbidity achieved by this kind of technique were 63.14%~77.10%,54.18%~60.54%,85.76%~87.98%,82.36%,79.28% respectively, and the coverage ratio of duckweed decreases from 90% to 10%. Compared with conventional wastewater treatment systems, the integrated restoration technique do not cause secondary pollution, and has an obvious effect, especially it can maintain good water quality for a long time.

Abstract: Through analyzing the water quality class of TN, TP of 14 reservoirs in Liaoning province and the change trend for many years, the algae experience formula is proposed using stumn combined with the actual weather conditions in Liaoning province . It can be concluded that although the TN pollution of the Liaoning province is heavy, the TP is well controlled. And the eutrophication of reservoir has not occurred for many years, because the restriction of TP is good .

Abstract: According to the analysis results of phytoplankton collected after July 2007, the dominant population is chlorella or cyclotella, and cell density of phytoplankton and content of chlorophyll-a are different as seasonal change. In 2007, reservoir water is classified as light eutrophic. Later degree of eutrophication declines and water quality become better. The occurence of eutrophication is promoted by something including much of nitrogen and phosphorus from upstream water, suitable temperature and illumination. Controlling nitrogen and phosphorus sources and strengthening artificially biologic chain are adopted to prevent eutrophication. Obvious effect has being achieved in recent years.

Abstract: Through the analysis on the data of monitoring water quality of typical reservoirs in Liaoning province, the major reservoirs in the province are in the state of mesotrophication or even eutrophication. The main pollutants are DO-consumption organic pollutants such as ammonia nitrogen and phosphorus. Despite years of special treatment, quality indexes about such nutrients are still high and they severely restrict improvement of the water quality. On the basis of the primary research, this article analyses the main reason for production of phosphorus and nitrogen, estimates the annual load of non point sources pollution and provides a basis for controlling of the pollution.

Abstract: As most of water bodies in urban ecological village landscape are closed or sluggish, in addition to point source and non-point source pollution, they are easy to be eutrophicated. Life and environment nearby will be influenced. In this paper, the combination of microorganism agents and aquatic plants were conducted to treat Xinhe East Canal water body. As a result, after 40 days of running, the removal rates of COD_Cr, NH₃-N, TN and TP were around 58.34%, 92.84%, 89.10% and 86.44%, respectively. And the concentration of Chlorophyll a decreased to less than 3 mg/m³. The main parameters can meet the demands of the standard of fifth type water body according to the Chinese environmental quality standards for surface water.

Abstract: This research has examined the aquatic plants ability of removing N and P with the experiment materials of the aquatic plants in the river system in Chaohu Region. Results revealed that Ludwigia peploides subsp, Vallisneria spiralis, Water Hyacinth and Cyperus papyrus contribute to removing TN in water to the effect which correlates the growth rate of the plants. 1) Particularly, Water Hyacinth, which grows the fastest among the sample plants, effects with the highest efficiency in removing TN, with the removal ratio of about 77%, 6.8 times that of the control group; 2) 4 aquatic plants function with higher efficiency in removing NH3-N than TN, and the plants in Test 8d remove NH3-N up to the removing ratio of 65-92% or so; 3) 4 aquatic plants tend to degrade NO₃^--N at the ratio similar to TN, and the absorptive effect of Water Hyacinth tops among the 4 plants, while under the same conditions, the papyrus remains the lowest with the absorptive ratio of only 31.7%; 4) and the regulation that the experiment plants remove the TP in water differs from TP degradation, for, in the early stage of the experiment, plants in Test 20d remove phosphorus at the high rate; however, in the later stage of the experiment, the concentration of phosphorus in water remains stable. At the end of the experiment, the phosphorus removal ratio reached 47.2%, while the ratio that the papyrus removed the phosphorus was only 21.5%. These data suggest that the aquatic plants in Chaohu Region can exert efficient remediation effect upon the eutrophic water.

Abstract: Objectives To assess the current eutrophication and heavy metal pollution condition of South Lake by monitoring the water quality of South Lake Central Ecological Park in Tangshan city and to provide basic information and science basis for the continuity environmental monitoring and further treatment. Methods The water samples in South Lake were collected during 10th-12st May, 2011. Samples of surface water in Xixingchi, Yanglongshui, and Qingtianjing were determined temperature, pH, turbidity, dissolved oxygen (DO), biochemical oxygen demand (COD), biological oxygen demand (BOD₅²⁰), total phosphorus (TP), ammonia nitrogen, nitrite nitrogen, nitrate nitrogen, Hg, As, Cr, Cu, Zn, Ni, Pb, Cd and so on. Single water quality index and the integrated pollution index were calculated to assess water quality of sampling point. Results The sense character of all sample points did not accord with national standards.The BOD₅²⁰ of Xixingchi, West Yanglongshui, North Yanglongshui and the four sampling points of Qingtianjing were more than national standards. The TP, ammonia nitrogen and nitrate nitrogen of Qingtianjings sample points exceeded national standards. Indicatorss of other sample were accord with national standards. Xixingchi, whichs comprehensive pollution index was 0.27, belonged to clean water. Yanglongshui, which`s comprehensive pollution index was 0.22, belonged to clean water too. Qingtianjing, whichs comprehensive pollution index was 1.99, belonged to polluted waters. Conclusions Xixingchi and Yanglongshui belongs to clean water. Qingtianjing belongs polluted water. The TP, ammonia nitrogen and nitrate nitrogen of Qingtianjings four sample points exceeded national standards. The severity of the pollution is: Qingtianjing>Yanglongshui>Xixingchi.

Abstract: Water blooms occurred in Xinlicheng reservoir in 2007 and eutrophication was paid attention on. The method of comprehensive eutrophication state index was adopted to assess eutrophication state and change of TN, TP, COD_Mn and pH were analyzed based on water quality monitoring data of Xinlicheng reservoir from 2000 to 2010. From 2003 to 2007, degree of eutrphication changed from mesotrophication to light eutrohpication. Eutrophication of Xinlicheng reservoir was caused by the pollution of nitrogen and phosphorus and the pollutant sources include extraneous and endogenous sources. Extraneous sources come from upstream water and periphery of the reservoir, while endogenous sources come from sediments. Ecological wetland should be constructed in estuarine area, fish and bivalves should be put into the reservoir and other comprehensive measures should be taken to control nitrogen, phosphorous and algae. Obvious effect has been achieved by eutrophication treatment measures.

Abstract: Based on the field measured results in the typical periods of flood season and dry season of Gucheng Lake, the present eutrophication levels of the lake were investigated by the Model of Butterfly Catastrophe, in which series of the environmental factors were considered including the ecological indicator of chlorophylla, the nutrient indicator of total nitrogen and total phosphorus, and the physical index of water transparency. The results showed that: the water eutrophication levels of Gucheng Lake were mal-distributed in space and time; the lake eutrophication tendency in flood seasons were more obvious than that in dry seasons; the eutrophication levels in the south part of the lake were relatively lower than that in the north and the average comprehensive mutation of fuzzy membership value in the south was about 0.3006 in the dry seasons. Due to the increased pollution load and the hydrodynamic conditions, the eutrophication degree in the estuary areas were higher and the fuzzy membership value was close to 0.235, achieving the medium eutrophication level.