Research Of Repair Effect Of Coastal Aquaculture Wastewater By Water Hyacinth

Water eutrophication has become a serious environmental problem because of disposal of aquaculture in mudflats to natural aquatic system. How to improve the quality of mudflats water and decrease the water eutrophication level has become an issue. Water hyacinth, as a floating plant, has a good ability for significantly decreasing water eutrophication. At present, there has been a large amount of research about the ability of water hyacinth on decreasing water eutrophication, but little on the possibility of using water hyacinth to recover the saline-alkaline water. Thus, we conducted a simulated mudflats aquaculture waste water experiment to investigate the ability of water hyacinth on purifying eutropHic water and the growth traits of water hyacinth in2009. The main results are as follows1. From the20th day, the removal speed of N and P in different salinities of Water eutrophication became faster significantly, when the salinity was10.Og NaCl/L, this recovery effect is more obvious and more than a half N were removed while only35%when the salinity was higher. When the salinity reached12.5g NaCl/L and higher, the removal effect of P decreased significantly, less than70%, but the effect had no differences to that in low salinity when in10.0g NaCl/L.2. Water eutrophication grew normally in each set, the increasement of biomass ranged from3.18%to13.93%, when the N concentration became higher, photosynthetic efficiency showed weakening then recovered, P has a certain inhibition to photosynthetic efficiency, stomatal conductance, intercellular CO2and transpiration rate were all enhanced when N concentration was low, but stomatal conductance, intercellular CO2became weaker as N concentration raising.3. After25days in the simulated aquaculture wastewater, Water eutrophication grew normally and had high absorption and use efficiency of N and P. Significant removal efficiency (more than90%) was observed in the treatments with the low-N and medium-N concentration. Uptake of N and P by E. crassipes was slightly higher in the saline/alkaline water than the fresh water. The absorption kinetics followed dual linear equation. The Km for N and P uptake was slightly but not significantly influenced by the different salinity in the water. The Imax for N uptake was not different between the saline and fresh water.4. The Water hyacinth during a short time had a adsorption effect of nitrogen and phosphorus in water, the highest absorb rate of TN reached44.62%and the rest sets were around30.00%, the best absorption effect of TP was58.88%cand the concentrations of TP after treat all were below0.0250mmol/L. The terrestrial-salinity-tolerant plants repair system had a significant purification effect of the water processed by the Aquatic-salinity-tolerant plants repair system in a short treat term, each set’s absorption effect of TP was better than that of TN. The total removal efficiency of TN were above70.00%and the highest one was86.48%while the removal efficiency of TP were all near90.00%and the highest one was99.51which nearly none. Only the root showed a little reduction of water content, other positions showed almost no change, there exist no significant differences each other.