Auto-flocculation microalgae species Tribonema sp. and Synechocystis sp. with T-IPL pretreatment to improve swine wastewater nutrient removal

It is recognized coupling microalgae, which is rich in lipids or protein with wastewater treatment offers extra economic benefits that can potentially make microalgal production feasible by reducing production costs and providing environmental benefits. However, the pretreatment of high concentration nutrients such as ammonia nitrogen (NH3-N), total phosphorus (TP) and chemical oxygen demand (COD) in swine wastewater is the premise of application for microalgae in wastewater treatment. This study two auto-flocculation microalgae Tribonema sp. and Synechocystis sp. were selected for evaluation; they were cultivated in diluted swine wastewater together after it was pretreated with titanium dioxide (TiO2) plus intense pulsed light (T-IPL). The results showed that the growth of the two strains in the wastewater pretreated with T-IPL grew better than when grown without the pretreatment. The content of lipid in the two algae, cultured in the pretreated wastewater, was also higher than the lipid content from the un-pretreated wastewater; but protein content was lower. Overall, the removal efficiencies of pollutants NH3-N, TP, and COD by the two microalgae in anaerobic digestion of swine wastewater (ADSW) with T-IPL pretreatment, were higher than the removal efficiencies without pretreatment. This research also indicates that these two auto-flocculation microalgae have the potential to reduce harvesting costs. And, using T-IPL to pretreat wastewater could provide a promising method for the pretreatment of wastewater.