T75 Boosting methane production from mixed microalgae (Scenedesmus sp., Chlorella sp.) anaerobic digestion: Influence of Pretreatment and digestate concentration
Tuesday, April 26, 2016
Key Ballroom, 2nd fl (Hilton Baltimore)
In this study, microalgae consortia was cultivated using digestate (source of N (nitrogen) and P (phosphorous) as substrate using microalgae consortia from a natural ecological niche. Three digestate concentrations were prepared using water as diluting agent and are denoted as I, II, III. The corresponding N (NH4-N) and P (PO3-P) concentrations were noted as 230, 90, 70 and 24, 7, 5 mg/L, respectively. After a cultivation period of 40 days, the N and P concentrations were 100% removed at 15th day. Additionally, first time an attempt towards the combination of ultra-sonication and electrolysis has been reported. The energy utilization and the organic matter solubilization is comparatively better in combination conditions than the individual conditions. Combination conditions yielded the soluble protein and carbohydrate as 279 and 309 mg/L, which is the recovery of nearly 85 and 90% in terms of total content of them. sCOD (chemical oxygen demand) release was measured as 1452 mg/L, around 88% of the tCOD (total COD). BMP tests were performed by using the digested sludge. The results indicated that more solubilization of organic matter does not enhance the methane production performances. After 40 days of anaerobic digestion, peak methane production performance was observed with the hydrolysate of combined pretreatment as 22 mL/g VS added, compared to the control experiment 10 mL/g VS added. The enhanced performance is attributed to the solubilized organic matter and also the formation of less inhibitors. This study, explored a possible pretreatment method for optimal bio refinery and AD from microalgal biomass.