title: Outdoor cultures of Chlorella pyrenoidosa in the effluent of anaerobically digested activated sludge: The effects of pH and free ammonia.
abstract: A freshwater algae Chlorella pyrenoidosa was cultured outdoors using anaerobically digested activated sludge effluent. The effects of pH variations were evaluated. The coupled pH variations and free ammonia toxicity significantly affected the algal growth, lipids accumulation and contamination control during every season. The free ammonia toxicity at high pH levels actually inhibited the algal growth. Compared to an optimal algal growth at a pH of 5.7-6.5, biomass productivity at a high pH of 8.3-8.8 was reduced by 67.15±6.98%, 54.39±6.42% and 83.63±5.71% in the spring, fall and summer, respectively. When the pH rose above 9.1-9.6, algae were unable to grow in the wastewater. However, high pH levels reduced contamination (e.g., bacteria and microalgae grazers) and triggered lipids accumulation in algal cells. These findings suggest that pH control strategies are essential for this type of algal wastewater system, where ammonia is the dominant nitrogen source.
authors.affiliation: State Key Laboratory of Pollution Control and Resources Reuse, Key Laboratory of Yangtze Water Environment for Ministry of Education, College of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China.
authors.forename: Xiao-Bo
authors.initials: XB
authors.lastname: Tan
authors.affiliation: State Key Laboratory of Pollution Control and Resources Reuse, Key Laboratory of Yangtze Water Environment for Ministry of Education, College of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China. Electronic address: zhangyalei@tongji.edu.cn.
authors.forename: Ya-Lei
authors.initials: YL
authors.lastname: Zhang
authors.affiliation: State Key Laboratory of Pollution Control and Resources Reuse, Key Laboratory of Yangtze Water Environment for Ministry of Education, College of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China.
authors.forename: Li-Bin
authors.initials: LB
authors.lastname: Yang
authors.affiliation: State Key Laboratory of Pollution Control and Resources Reuse, Key Laboratory of Yangtze Water Environment for Ministry of Education, College of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China.
authors.forename: Hua-Qiang
authors.initials: HQ
authors.lastname: Chu
authors.affiliation: State Key Laboratory of Pollution Control and Resources Reuse, Key Laboratory of Yangtze Water Environment for Ministry of Education, College of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai 200092, China.
authors.forename: Jun
authors.initials: J
authors.lastname: Guo
mesh_terms: D000641:Ammonia / Q000737:chemistry*; D000693:Anaerobiosis; D018533:Biomass; D002708:Chlorella / Q000254:growth & development*; D004952:Esters; D005227:Fatty Acids / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008055:Lipids / Q000737:chemistry; D058086:Microalgae / Q000254:growth & development; D009584:Nitrogen / Q000737:chemistry; D010758:Phosphorus / Q000737:chemistry; D012722:Sewage; D013696:Temperature; D062065:Wastewater / Q000382:microbiology
chemical_list: D000641:Ammonia; D004952:Esters; D005227:Fatty Acids; D008055:Lipids; D009584:Nitrogen; D010758:Phosphorus; D012722:Sewage; D062065:Wastewater
keywords: Anaerobically digested activated sludge; Chlorella pyrenoidosa; Contamination control; Free ammonia; pH