Behaviours of 7 organic phosphate esters (OPEs) in several water treatment processes were studied. The results are as follows :
1) TOP,
TPP
and TCP showed rapid decrease (48 hours after, 40-60%) in activated sludge biodegradation. TBP and CRP were in the intermediate range, and TCPP and TCEP were degraded hardly. Effect of acclimation was appeared for TBP, TCPP,
TPP
and TCP.
2) The OPEs except for TBP and TCPP showed NaOH hydrolysis. TCEP, CRP,
TPP
and TCP showed rapid decrease (1 hour after at pH 13, 80-100%), and TOP were degraded more slowly.
3) TOP and TCP were removed by the coagulating sedimentation with
Al22
(SO
4)
3, FeCl
3 and PAC effectively (maximum, 80-95%), and
TPP
was removed with FeCl
3 and PAC (20-25%). In the coagulating sedimentation with Al
2(SO
4)
3, maximum removal rate was shown in the range between pH 5 and pH 8.
4) All OPEs were adsorbed on activated carbon powder very effectively (at 0.1 g/l, 90-100%), and
TPP
and TCP were most adsorbent. Freundlich equation was applicable to the adsorption isotherms of OPEs.
5)
TPP
amd TCP were rapidly destroyed by UV irradiation with low and high pressure mercury lamps (1 hour after, 100%). TBP and TOP were in the intermediate range, and TCPP, TCEP and CRP were destroyed more slowly.
6) TOP,
TPP
and TCP reacted with chlorine, especially under acidic conditions, even at the low chlorine concentration (3 mg/l).
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