Abstract:

In order to reduce the aquaculture wastewater,this paper discussed the effect on water quality by the snail(Bellamya purifica)and macrophyte(Vallisneria spiralis)through constructing the snail and macrophyte ecological system and comparing the purification effects by the snail and macrophtye with different density.The result showed that all the snail and macrophyte treatments of various density had good purification effects,but by contrast,the middle density one(50ind/m3)worked best.The removal rates of Chla,CODMn,TN, TP,NH4+N,NO3-N and the turbidity were 98%,397%,442%,869%,582%,823% and 91%,respectively in the 25 days’experiment,among which the 17~25 days’nutrient had the highest removal rate.And the water quality had evolved from the level of Ⅳ and Ⅴ to Ⅲ.Since there was only a slight difference in purification between the Bellamya purifica and Vallisneria spiralis,the mutually beneficial relationship between them was not obvious.However,perhaps due to the loess sediment caused by the shortage of heterotrophic microorganism,the removal effect of CODMn and TN by 〖WTBX〗Bellamya purifica and Vallisneria spiralis was not perfect