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Submerged vegetation restoration on water source protection zones Gonghu river pollution reduction technology

Author: WangYangYang
Tutor: QuXianCheng；HePeiMin
School: Shanghai Ocean University,
Course: Hydrobiology
Keywords: Eutrophication Assessment Submerged aquatic plants Photosynthetic characteristics Nitrogen and phosphorus absorption Ecological restoration
CLC: X524
Type: Master's thesis
Year: 2011
Downloads: 123
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Abstract

Currently, water pollution and water shortages are faced in today's global freshwater resources of the two crises. In particular water source occurrence of cyanobacterial blooms drive growth trend, a great threat to people's drinking water safety. Therefore, controlling water source protection areas exogenous and endogenous nutrient load, reducing the level of eutrophication in lakes, rivers, restore the health of freshwater ecosystems has become an important issue to be solved. In this paper, Taihu Lake water source protection zones tribute land protection within the river into the lake pollution characteristics for pollution abatement technology research, and to evaluate the effects of ecological restoration research. First, the source protection zones Gonghu river eutrophication status of the investigation and assessment; Secondly, the study of light, temperature screening of indigenous and submerged plant photosynthetic characteristics; Third, carried out with different nitrogen turbid waters submerged plants Phosphorus Uptake studies, and based on laboratory findings by conducting cold water purification submerged plants in situ enclosure experiments; Fourth, in the villa Gonghu Golden Bay rivers carry water source to recover submerged plants mainly river pollution reduction technology research, build and optimize Daphnia magna guided submerged vegetation restoration ecological restoration engineering technology and continuous adjustable beds of submerged plant cultivation ecological restoration techniques, and the results were evaluated ecological restoration research. The main results are as follows: 1. Gonghu water source rivers into the lake eutrophication survey and evaluation of the 2008-2009 water in Taihu Lake tribute to Kim villa Hong Kong, frog Hong Kong, Tong Hong Kong and other three major rivers of water quality and aquatic seasonal biological characteristics were investigated. Gonghu river water source eutrophication risk, primarily nitrogen and phosphorus pollution indicators, the annual average concentration of TN was 3.094 mg / L, TP average concentration of 0.112 mg / L. June total phytoplankton density was significantly higher than in March, mainly in Cyanophyta, Chlorophyta and diatoms dominated the door. Macrophytes survey results show that only see reeds spring, summer and autumn, but a large increase in the amount of a single type of aquatic plants, which are mainly denominated in Hong Kong gold villa daisy grass-based, which cover up to 90%, followed by a Ceratophyllum, Myriophyllum spike algae and other submerged plants; floating plants Spirodela biomass maximum coverage of 60%. Three river water hyacinth and floating-leaved reed biomass of emergent plants more. Winter no large aquatic plants. Water sources are in the spring and summer eutrophic state, in which the spring reaches moderate eutrophication (LTI (Σ) = 64.113), the autumn season in the source water quality of nutrition (LTI (Σ) = 53.526) 2. Light, temperature Submerged plants on photosynthetic characteristics of fluorescence was measured using the PAM Vallisneria (Vallisneria spiralis) optical system PS Ⅱ photochemical efficiency (Fv / Fm) and other photosynthetic parameters. Low-light conditions at different temperatures between eelgrass optical system PS Ⅱ photochemical efficiency (F _v / F _m) value was not significant (P gt; 0.05). 25 ℃, the experimental light range F _v / F _m values ??with the highest average value 0.75. The entire temperature range, the initial fluorescence F ₀ with light did not change significantly (P gt; 0.05), low temperature on F ₀ almost no effect, suggesting that F ₀ has a certain resistance to low temperature, and the initial fluorescence F ₀ in response to high temperature is 35 ℃, 25 ℃ relative increase. Maximum temperature on eelgrass relative electron transport rate was significantly affected than light (P lt; 0.05). Transparency and underwater light intensity displayed in the derivation of water clarity is less than 0.9 m when submerged plant Vallisneria was growing light confinement system came under in the end, photosynthesis efficiency. 3 Different turbid waters submerged plant nitrogen and phosphorus absorption properties of studied eelgrass (V. spiralis), green chrysanthemum grass (Cabomba.sp), Hydrilla (Hydrilla verticillata) in the muddy waters of the nitrogen and phosphorus absorption characteristics and three plants on water turbidity effects. The results showed that three kinds of submerged plants on water turbidity removal had good results, three kinds of submerged plants mixed group training, its turbidity decreased rate of 99.73%, while Hydrilla and Vallisneria were 96.64% and 90.36%, while the control group was 80% decrease. In turbid water, three kinds of submerged plants mixed planting, TN, NO ₃ ^{- -N and Chl a content decreased significantly higher than other groups (P lt; 0.05 ); against PO ₄ ^{3 - -P, TP, COD _Mn absorption effect is not obvious. 4 hardy submerged water purification plants in situ mesocosm study through laboratory experimental study of cold acclimation submerged plant Vallisneria (V. spiralis), Elodea (Elodea Canadensis) in the winter on the water quality of water sources Gonghu purifying effect. Eelgrass experimental group, the experimental group Elodea, Vallisneria Elodea experimental group were reduced to three forms of nitrogen before the experiment 78.76%, 70.20%, 83.42%, 81.85%, 72.30%, 75.55%, 88.80%, 78.80 %, 86.21%, while the control group and the nitrogen concentration of water outside the enclosures changed little, TN concentrations were reduced by 37.12% and 15.87%; eelgrass Elodea experimental group the TP and COD _{Mn The removal efficiency was significantly higher than the purification efficiency was significantly higher than other enclosures (P lt; 0.05), respectively, 86.97% and 76.16%; through domestication bitter grass and Elodea better in the winter and water purification effect purifying effect: eelgrass Elodea gt; eelgrass gt; Elodea. 5 Gonghu submerged vegetation water source construction and pollution reduction effects Daphnia magna boot field experiments submerged vegetation restoration ecological restoration system on the gold villa Bay creek water bodies TN, TP, COD _Mn, NO ₂, NO ₃ removal of a significant role in promoting (P lt; 0.01), concentrations were lower than before restoration of 52.9%, 73.1%, 47.1%, 78.0 percent and 71.1 percent, increase transparency 70cm, up to the national surface water quality standard Ⅲ. Adjustable beds submerged plant network technology on the river and creek water NH ₄-N removal rate was significantly higher than other forms of nitrogen. Purifying effect on total phosphorus than PO ₄ ^{3 - -P high purification effect. Phosphorus concentration in the control area did not change significantly. Exogenous load bearing capacity experiments show that the introduction of 1/4 volume, the river ecosystem nutrient reduction effects were higher, in which the reduction of orthophosphate rate of 80%. With exogenous nutrient load continues to increase, the purification efficiency of the river journey downward trend, while TN load 5310.018g, the river still on the TN removal of 44%.}}}}

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CLC: > Environmental science, safety science > Environmental pollution and its prevention > Water pollution and its control > Lakes and reservoirs
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