Electroless nickel plating waste water

I have problems with Phosphorous in my waste water plant. The FeCl3 and Ca(OH)2, even in great quantity, are not sufficient to precipitate the Phosphorous salts, probably because the main quantity of them is due to the Hypophosphites and Phosphites that have lower reactivity than Phosphates.

Can someone indicate me how to solve the problem?

I'm speaking of about 100 ppm of P to be reduced within a limit of 10 ppm.

Many thanks

I don't have an answer other than to try to close loop your rinse water to the plating tank. But I would like to point out that in addition to the hypophophite you also have orthophosphite formed from the 'consumption" of the hypophosphite". It is this material that may be the cause of your problem.