Is seashell powder suitable for phosphate recovery from fermentation broth?

This communication elaborates on the use of seashell powder (SP) for the removal of phosphate from lactic acid-containing fermentation broth. Despite extensive past research regarding the application of SP for phosphate removal from wastewater, no information is available for solutions containing various organic compounds. In order to fill this knowledge gap, tests were performed with pure phosphate solution (PPS) and PPS containing 0.83 M of three alcohols, ethanol, propanol or 1,2-propanediol, or 0.83 M of three organic acids, acetic, propionic or lactic acid. Furthermore, a real fermentation broth (RFB) obtained from the fermentative production of lactic acid from food waste was tested. Using 4.8 g SP, more than 95% of phosphate, present at an initial concentration of 50 mg L−1, could be removed from PPS and PPS containing alcohols after 120 min. The presence of organic acids reduced the removal capacity of SP and only 55%–73% of the phosphate initially present was removed. The presence of lactic acid also substantially affected the removal of phosphate from RFB when 132 mg L−1 phosphate was initially present: after 120 min, only 28.6 mg L−1 of phosphate had been removed. The results indicate the use of SP for phosphate removal from fermentation broth, contributing to multi-component utilization of fermentation broth. However, the effects of respective fermentation products on removal capacity should first be tested.