Influences of iron and calcium carbonate on wastewater treatment performances of algae based reactors

• Published in: Bioresource technology 2016-09, Vol.216, p.1-11
• Main Authors: Zhao, Zhimiao, Song, Xinshan, Wang, Wei, Xiao, Yanping, Gong, Zhijie, Wang, Yuhui, Zhao, Yufeng, Chen, Yu, Mei, Mengyuan
• Format: Article
• Language: English
• Subjects: Algae based reactor; Bacteria; Bioreactors - microbiology; Calcium carbonate; Calcium Carbonate - chemistry; Iron; Iron - chemistry; Waste Water - chemistry; Wastewater treatment; Water Purification - methods
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2016.05.043

[Display omitted] •Accumulated HCO3− driven by carbonate–bicarbonate increased algae biomass.•10μM Fe3+ allowed 20-day continuous operation with high removal efficiency.•A synergistic effect exists among Fe3+, iron, and CaCO3. The influences of iron and calcium carbonate (CaCO3) addition in wastewater treatments reactors performance were investigated. Adding different concentrations of Fe3+ (5, 10, 30 and 50mmol/m3), iron and CaCO3 powder led to changes in algal characteristics and physico-chemical and microbiological properties. According to the investigation results, nutrient removal efficiency in algae based reactors was obviously increased by the addition of 10mmol/m3 Fe3+, iron (5mmol/m3) and CaCO3 powder (0.2gm−3) and the removal efficiencies of BOD5, TN, and TP in Stage 2 were respectively increased by 28%, 8.9%, and 22%. The improvements in physico-chemical performances were verified by microbial community tests (bacteria quantity, activity and community measured in most probable number, extracellular enzymes activity, and Biolog Eco Plates). Microbial variations indicated the coexistence of Fe ions and carbonate–bicarbonate, which triggered the synergistic effect of physico-chemical action and microbial factors in algae based reactors.