Innocent Treatment And Utilization Of Water Hyacinth

As an alien invasive species,water hyacinth has caused terrible ecological disaster in many places.How to take full advantage of water hyacinth with high efficiency has become critical to solve the problem after water hyacinth was salvaged.This paper completed the study of water hyacinth’s optimal growth conditions,and obtained the best conditions for water hyacinth growth.Water hyacinth was also applied to ecological treatment,such as purify contaminated water and accumulate heavy metal.Moreover,this paper proposed a new method for innocent treatment of water hyacinth to realize resourceful utilization.The results of this study will have high ecological and social value.In this study,The optimal growth conditions of water hyacinth proliferation were investigated.The results show that the optimized conditions for water hyacinth growth were as follows:earthworm manure concentration 1.27%(TN 14.76 mg/L,TP 3.77 mg/L),carbon source concentration 0.45‰ and pH value 7.0.Under these conditions,the weight gain rate,the main stem growth rate and tiller number of water hyacinth were significantly improved.Moreover,it was found that one week was needed for water hyacinth to adapt to the new environment,and the water pH value rised gradually with the prolonged cultivation time.The optimum conditions were investigated for the treatment of eutrophication water using water hyacinth.As earthworm manure concentration is 1.0%(TN 12.43 mg/L、TP 3.07 mg/L、COD 29.5 mg/L),the optimized batch culture conditions were as follows:water pH value 7.07,growth density 250 g/m2 and circulation flow rate 22.6 L/min.Under these conditions,the removal rate of TN,TP and COD were 92.3%,79.25%and 82.23%,respectively.Growth space limitation led to a poorer purification capacity of water hyacinth at the late growth stage.Thus,it is important to control reasonable growth density of water hyacinth for eutrophication water treatment.Based on these results,the effect of continuous cultivation on the treatment of eutrophication water was also investigated.The results show that the optimal hydraulic loading rate was 0.019 m3/h/m2.Water hyacinth was examined for its ability to endure and accumulate Pb2+ and Cd2+.The results show that the maximum tolerated concentrations of Pb2+ and Cd2+ for water hyacinth were 10 mg/L and 5 mg/L,respectively.Under these conditions,both SOD and POD activity reached the highest value.In addition,the highest enrichment coefficient and removal rate of Pb2+occurred when the concentration of Pb2+ was 1.0 mg/L,along with the Pb2+ concentration of 213.06 mg/Kg and 176.84 mg/Kg,respectively,in the roots and stem leaf of water hyacinth.The highest removal efficiency of Cd2+occurred when the concentration of Cd2+ was 0.5 mg/L,along with the Cd2+concentration of 169.23 mg/Kg and 124.17 mg/Kg,respectively,in the roots and stem leaf of water hyacinth.The preparation process of planting concrete made from water hyacinth was investigated,and its application properties were also evaluated.The results show that the optimized conditions were as follows:water hyacinth content 10%,sand content 68%,cement content 32%and water-material ratio 0.80.Under above conditions,the slump of slurry was 124 mm,the compressive strength,porosity and pH value of planting concrete were 1.15 MPa,33%and 9.2,respectively.Moreover,it was found that the germination rate of seed in planting concrete was much higher than that of plain concrete.Compared with plain concrete and planting concrete,planting concrete combined with plant showed a better performance on eutrophication water treatment and heavy metal accumulation.