Review on Pond Aquaculture Tail Water Treatment Technologies

Carrying out the treatment of aquaculture tail water and realizing the discharge and recycling of the aquaculture tail water are the inevitable trend in the development of the fishery industry at present and in the future.For this reason,this paper reviewed the characteristics of pond aquaculture tail water,the sources of pollutants in intensive aquaculture tail water,the important parameters in the water body that affect the growth of cultured organisms,and the water treatment methods in the process of aquaculture,and prospected from the technical level and industrial policy level,hoping to accumulate data for promoting the green development of aquaculture and cleaner production.

Comparison on Purification Effect of Two Macroalgae Species on Prawn Tailwater

[Objectives]This study was conducted to investigate the purification effects of two common large seaweeds on the tail water of prawn farming in greenhouses,and to determine the best culture density of seaweeds.[Methods]Two large seaweed species,Gracilaria lichevoides and Ulva lactuca,were selected to set four culture densities of 0.5,2,4 g/L and a blank control group,respectively.The seaweeds were cultured in 100 L white polyethylene buckets,each of which contained 50 L of tail water from prawn culture.[Results]After 5 d,the nutrient removal rates of the two seaweeds were directly proportional to the density.There was no significant difference in NH_(4)-N removal rate between G.lichevoides and U.lactuca(P>0.05)by two-way analysis of variance,and the NH_(4)-N removal rate of the latter was higher.The removal rates of NO_(3)-N,TN and TP by G.lichevoides were significantly higher than those by U.lactuca(P<0.05).The specific growth rates of seaweeds were negatively correlated with their culture densities.The specific growth rates of G.lichevoides were 5.73%,1.654%and 0.48%,respectively,and those of U.lactuca were 2.01%,1.187%and 0.138%,respectively,when the culture densities were 0.5,2.0 and 4.0 g/L.Two-factor analysis of variance showed that the former was significantly higher than the latter,when the culture density of the two species of seaweeds was 0.5 g/L(P<0.05).The two-way analysis of variance showed that when the culture density of the two kinds of seaweeds was 0.5 g/L,the specific growth rate of G.lichevoides was significantly higher than that of U.lactuca(P<0.05).Based on the above research,the two macroalgae could reduce the nutrients in the wastewater to a large extent,but the culture density determined the scale and economic benefits of seaweed cultivation and further affected the normal growth,metabolism and quality of the seaweeds.[Conclusions]This study provides some theoretical basis for large-scale seaweed farming and biological selection of in-situ ecological restoration of eutrophic seawater.

THE SYSTEM OF MODEL CONTROL AND DATA ACQUISITION IN THE HUAIHE RIVER FLOOD CONTROL MODEL

The area of the Huaihe river flood control model is 4000m2. A computer system is employed to control models and collect experimental data.It can control 7 inflows which simulating 9 typical years flood process, a tail water level, 6 sluices, 11 outlets of breaking dike, and collect the water level of 37 points and velocity of 32 points.After running long time,the system has ben proved that it possesses steady character and exact accuracy.It is essential precondition for the experimental study of the Huaibe river find control model.