Abstract: At present,ecological environment pollution from large-scale poultry and livestock breeding has become increasingly serious due to the release of feces containing huge amount of nitrogen and phosphorus,heavy metals and organic pollutants;therefore,the duty of treating the wastewater is extremely urgent. Since the deficiency of traditional wastewater harnessing,the wastewater treatment based on microalgae biotechnology has become more attractive. Microalgae is a kind of unicellular organism that widely exist in water,has efficient ability of removing nitrogen and phosphorus and detergency;the major mechanism of which is as such,it adsorbs the nitrogen by anabolism,absorbs and precipitates phosphorus by phosphorylation,besides,the functional group of its cell membrane plays an important role on heavy metal enrichment. The adsorption rate of most microalgae for nitrogen,phosphorus and enrichment rate of heavy metals was 80% based on these physiological foundations. The researches about microalgae disposing the polluted compounds of breeding wastewater are focused on nitrogen,phosphorus and heavy metals,and the High Rate Algal Ponds（HARP）,active algae,immobilization technology,and the photobioreactor are usually choices for practical application. However,there are still a lot of challenges for this technology,such as the rare research on molecular mechanism and the deficiency of practical experience. Based on the mechanism of harnessing livestock wastewater by microalgae,this paper overviews the efficiency of several algae removing nitrogen,phosphorus and heavy metals,summarizes the status and existing problems in domestic and international researches of wastewater harnessing by microalgae,and prospects the future of microalgae-wastewater engineering.

Key words: livestock wastewater, microalgae cultivation, sewage purification, nitrogen and phosphorus removal, heavy metal enriching