Abstract: This article mainly studied the biological purification of greenhouses prawn effluent with the blood clam (Tegillarca granosa) and different levels of effective microorganisms (EM), in order to build a new and efficient integrated farming structure, and to reduce the marine sewage discharge. The blood clams and EM were reared in 100 L white polyethylene plastic barrels added with 60 L prawn pond effluent per barrel. There was no water exchange and no throw in bait during a trial for 7 days. Five groups with three replications each were set up. Group 1-4 had 33 blood clams and 390 μL, 510 μL, 720 μL and 0 μL EM bacteria, respectively. Group 5 used as control with no blood clam and EM bacteria. The results showed that the purification efficiency of group 1-4 was higher than that of the control group. The nutrient removal efficiency of group 2 was the highest, which can remove 68.61%±0.25% of nitrate, 85.34%±2.94% of phosphate, 72.85%±3.62% of ammonia nitrogen, 59.24%±3.16% of total nitrogen and 79.82%±2.15% of total phosphorus. Purification effect reduced successively in group 1, 3 and 4. The analysis showed that the 510 μL EM bacteria and 33 blood clams were the most suitable proportion, and their ability to purify waste water was significantly higher than that of other groups, which could provide reference for constructing new and efficient integrated breeding structure.

Key words: EM(effective microorganisms), blood clam, aquaculture effluent, purifying effect, microecologics