Effect of Remineralization on Ozonation and Biodegradation of
R. Desjardins, C. J. Zoungrana, M. Provost.
Polytechnic of Montreal, Canada.
Surface water with low mineralization is often high in natural
organic matter. These characteristics make treatments designed to
produce drinking water difficult. In order to improve the
treatment, some water distributors have introduced a
remineralization stage in the treatment line that consist in
increasing alkalinity and the hardness of the water by adding
calcium ions and bicarbonates ions. The position of the
remineralization in the line varies, depending upon the desired
objective (buffer effect at the coagulation stage, correction of
aggressivity, direct oxidation by ozone, etc.). Tests were carried
out in order to show the effects of remineralization on the
evaluation of biodegradability of natural organic matter and on
some disinfection of by-products during ozonation and
biodegradation. These treatment steps are preceded by coagulation-
flocculation-decantation and sand-anthracite filtration. Results
have shown that remineralization increase the reduction of UV
absorbance by ozonation. Remineralization also increases the
production of oxalate and biodegradable dissolved organic carbon
(BDOC). Results have also shown that remineralization increase
removal of chlorine demand, chloropicrine and haloacetic acids by
biological treatment (ozonation and biodegradation).
Source: 2nd International Symposium on Ozone Applications
Havana, Cuba – Mach 24-26, 1997.