Microalgae cultivation and culture medium recycling by a two-stage cultivation system

摘要

Nutrients and water play an important role in microalgae cultivation.Using wastewater as a culture medium is a promising alternative to recycle nutrients and water,and for further developing microalgae-based products.In the present study,two species of microalgae,Chlorella sp.(high ammonia nitrogen tolerance)and Spirulinaplatensis (S.platensis,high growth rate),were cultured by using poultry wastewater through a two-stage cultivation system for algal biomass production.Ultrafiltration (UF)or centrifuge was used to harvest Chlorella-sp.from the first cultivation stage and to recycle culture medium for S.platensis growth in the second cultivation stage.Results showed the two-stage cultiyation system produced high microalgae biomass including 0.39g·L^-1 Chlorella sp.and 3.45g·L^-1 S.platensis in the first-stage and second-stage,respectively.In addition,the removal efficiencies of NH4+reached 19% and almost 100% in the first and the second stage,respectively. Total phosphorus (TP)removal reached 17% and 83%,and total organic carbon (TOC)removal reached 55% and 72% in the first and the second stage,respectively.UF and centrifuge can reeycle 96.8% and 100% water,respectively.This study provides a new method for the combined of pure microalgae cultivation and wastewater treatment with eulture medium recycling.