Influencing factors for nutrient removal from piggery digestate by coupling microalgae and electric field

ABSTRACT

Microalgae show great potential for nutrient removal from piggery digestate. However, full-strength piggery digestate have been found to severely inhibit microalgal growth. In this study, microalgae were coupled into the electric field (EF)system to form an electric field-microalgae system (EFMS). The effects of EF characteristics and environmental conditions on the growth of Desmodesmus sp. CHX1 and the removal of nitrogen and phosphorus in EFMS were explored. The results indicated that the optimal EF parameters for forming a fine EFMS were electrode of Zn (anode)/graphite (cathode), electric frequency of three times per day (10 min/time) and voltage of 12 V. The suitable light intensity and microalgae inoculation concentration for the EFMS were 180 μmol photons/(m²·s) and 0.2 g/L, respectively. Ammonium nitrogen and total phosphorus removal efficiencies were 65.38% and 96.16% in the piggery digestate by EFMS under optimal conditions. These results indicate that EFMS is a promising technology for nutrient removal from piggery digestate.

GRAPHICAL ABSTRACT

KEYWORDS:

• Microalgae
• electric field
• nutrient removal
• electrode materials
• light intensity

Acknowledgement

The authors thank the financial support from the Key Research and Development Project of Shangrao City, Jiangxi Province, China (NO. 2021D001) and Key Program of the Natural Science Foundation of Guizhou province, China (No. 20191452).

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

Data are available on request from the authors.

Additional information

Funding

This work was supported by Key Research and Development Project of Shangrao City, Jiangxi Province, China [grant number 20191452]; Key Program of the Natural Science Foundation of Guizhou province, China [grant number No. 20191452].