Treatment and resource utilization of dairy liquid digestate by nitrification of biological aerated filter coupled with assimilation of Chlorella pyrenoidosa.

Qin, Lei; Wang, Bo; Feng, Pinzhong; Cao, Yinghan; Wang, Zhongming; Zhu, Shunni

Ammonia inhibition is considered a key issue when using liquid digestate for microalgae cultivation. To study the effect of pretreatment with a biological aerated filter (BAF) on microalgae culture with dairy liquid digestate, nitrification characteristics of BAFs under different hydraulic retention time (HRT) and the growth characteristics of Chlorella pyrenoidosa in effluents of BAFs were investigated. Results showed that the BAFs can rapidly nitrify ammonia nitrogen and significantly improve the light transmittance of liquid digestate (the maximum promotion rate was ~260%), and the effect improved as the HRT increased. Pretreatment of liquid digestate with BAFs can eliminate ammonia inhibition for C. pyrenoidosa. Furthermore, lipid, crude protein, and higher heating value (HHV) output were also not affected by HRT. The similar removal of nitrate nitrogen in microalgae culture systems using effluents with 6-h and 12-h HRT (21.59% and 21.07%, respectively) were recorded. The results suggested that BAF coupled with microalgae culture is a novel option on the resource utilization of dairy liquid digestate.

CHLORELLA pyrenoidosa; NITRIFICATION; LIQUIDS; RF values (Chromatography); MICROALGAE; UPFLOW anaerobic sludge blanket reactors

Environmental Science & Pollution Research, 2022, Vol 29, Issue 3, p3406

0944-1344

Academic Journal

10.1007/s11356-021-15903-1