be controlled at 2:1. In fact, the NaOH pyrogenation process cannot
entirely avoid the formation of the byproducts [e.g., Mg3(PO4)2
and Mg2P2O7]. Through the analysis of published literatures, it was
found that the large consumption of NaOH and the formation of
byproducts may be the main obstacles to the further development
of struvite recycling technology. To avoid the formation of Mg2P2O7
in the pyrogenation of struvite, Huang et al. (2014) proposed the
chlorination decomposition process of struvite, and found that
the main components of the decomposition process were newberyite,
dissolved HPO4
2−and Mg2+, and magnesium phosphate
(MP).Although this process well resolved the problem ofthe formation
of Mg2P2O7, unfortunately, it only reduced a small amount of
the struvite precipitation cost (34%) due to the large consumption
of sodium hypochlorous. As for how to reduce the consumption of
NaOH, to the best of our knowledge, there is no study dealing with
this problem.