Study On Water Treatment Techniques And Benefits Of Different Culture Modes Of Litopenaeus Vannamei

Water must be cultivated before shrimp culture.It is very important to develop the equipment of purification technology of aquiculture's water quality in order to improve the culture environment and increase the success rate of aquaculture.In this paper,the removal efficiency and effect of suspended particles,soluble organic matter and nutrients in the water of aquaculture ponds were studied by means of water treatment and purification equipment such as sand filter,foam separator,biological processor,ozone generator,and ultraviolet light.The improvement effect of above equipment on the physical and chemical indexes of water body such as dissolved oxygen,chemical oxygen consumption,p H value,ammonia nitrogen,nitrite nitrogen and were studied respectively.And on this basis,the water treatment links are optimized to achieve the optimal water purification effect.The water purification effect of various water treatments and purification equipment is continuously monitored in both the high-level pond and factory culture modes of Litopenaeus vannameii.The culture period was 91 days,and the growth status,breeding effect and economic benefit of L.vannamei under different culture modes were evaluated..The experimental results are as follows:1.The sand filter has significant purification effects on yellow vibrio and green vibrio and heterotrophic bacteria(P<0.05),and the removal rates are 87.98%,92.30% and 72.26%,respectively.And it has significant adsorption and retention effects on the activity of phosphorus,total phosphorus,total hardness,total iron and COD and other colloids,metal ions and organic substances,and the removal rates are 28.85%,43.07%,5.06%,77.18% and 41.89%,respectively,While the effects on p H and salinity were not significant(P > 0.05).After continuous operation for 50 days,the filtration effect of sand filter decreased obviously,and the content of some water quality indexes increased after the treatment of sand filtration.Therefore,backwashing is required,and the specific backwashing frequency needs further study.2.Under different operating conditions,the average removal rates of SS,ammonia nitrogen,nitrite nitrogen,and COD by the foam separator were 48%,0.4%,4.4%,and 27.9%,respectively.Construct the regression equation for the removal rate Y and initial water concentration X1 n,power X2,hydraulic retention time X3,separator height X4.SS removal rate Y1=0.550+0.001 X11+ 0.008 X2+0.002 X3-0.015 X4;nitrite removal rate Y3 =0.144 X13+0.008 X2;COD removal rate Y4= 0.008 X2+0.038 X14+0.002 X3-0.015 X4.The regression equation model constructed in this study has a certain statistical significance.The power and hydraulic retention time of the foam separator are positively correlated with the removal rate,while the foam separation height has a significantly negatively correlated(P<0.05).3.Both UV and ozone disinfection can significantly remove Vibrio and heterotrophic bacteria in water,but the effects on p H value COD,ammonia nitrogen and nitrite is not obvious.The optimal process of UV disinfection treatment group was power 10 w,treatment time was 15 min,and water body size was 6L.Under there condition,the removal rates of yellow vibrio,green vibrio,heterotrophic bacteria,and COD were 97.59%,100%,94.46% and 0.65%,respectively.The optimum process in the ozone treatment group were ozone concentration was 0.3g/L,treatment time was 30 min,water body size was 4L,and the removal rates of yellow vibrio,green vibrio,heterotrophic bacteria,and COD were 60.95%,60%,54% and 0.41%,respectively.UV disinfection treatment is better than ozone disinfection.4.During the operation of industrialized aquaculture water treatment system,the ammonia,nitrite,chemical oxygen demand,and SS concentration of the system's effluent were 0.51±0.16 mg/L,0.24±0.07 mg/L,2.98±0.33 mg/L and 23.45±3.02 mg/L respectively,significantly lower than that in the culture ponds(P<0.05)whose removal rates were 70%,33.33%,49.91%,and 77.38%,respectively.5.After 91 d breeding in the mode of factory culture,the survival rate of Litopenaeus vannamei was 72%;the unit yield was 7.4 kg/m2,the feed coefficient was 1.12;and the ratio of yield to output was 1:1.46.And in the mode of high-level pond,the survival rate of shrimp was 56%;the unit yield is 3.8 kg/m2;the feed coefficient was 1.42;the ratio of yield to output was 1: 1.47.