Ammonia toxicity is a major disadvantage of microalgal growth when high-strength ammonium wastewaters like manure-free piggery wastewater (MFPW) were used as microalgal growth medium. In the present study, the effect of ammonium concentration, carbon/nitrogen ratio, and pH on ammonia toxicity of Chlorella vulgaris cultivated in the MFPW and nutrients removal was investigated. The three important parameters affected ammonia toxicity of C. vulgaris and nutrients removal of the MFPW significantly. The ammonium concentration of the MFPW could be decreased by air stripping. Microalga grew best at a carbon/nitrogen ratio of 25:1 with the maximum biomass concentration of 3.83 g L−1, the highest cell viability of 97%, and the removal of 100% ammonia, 95% of total phosphorus, and 99% of chemical oxygen demand. Ammonia toxicity was alleviated by pH control. The application of the established strategies can enhance nutrients removal of the MFPW while mitigating ammonia toxicity of C. vulgaris.
Bibliographical noteFunding Information:
This work was supported in part by grants from the National Natural Science Foundation of China (Grant No. 21767017 ), and the Science and Technology Project of Jiangxi Provincial Department of Science and Technology , China (Grant No. 20171BBF60024 ), and the Innovation and Entrepreneurship Development Fund of “Thousand Talents Program” Talent of Jiangxi Province, China (Grant No. 1001-02102082 ).
- Ammonia toxicity
- Manure-free piggery wastewater
- Nutrients removal