Bromate Control By Ammonia In Ozonation

Ozone-based technology has been applied widely in the drinking water treatment. But it may create a high carcinogenic bromate by-product for human body. Bromate has a variety of control methods at present and ammonia is one of them. However, researchers have just many studies for NH4 +relatively at present, gas phase ammonia is currently no studied. Therefore, this issue presents a new method to explore inhibition effect of bromate for gas phase ammonia through the comparison of gas phase ammonia and liquid phase ammonia on bromate inhibition.At first, paper studies the reverse-flow bubble column experiment and results show: bromate inhibition rate of gas phase ammonia is 52%-60% and bromate inhibition rate of liquld phase ammonia (ammonium chloride) is 53%-62%. Gas phase ammonia and liquild phase ammonia have a similar bromate inhibition rate. So gas phase ammonia is not for the advantages of liquid phase ammonia in bromate inhibition. For the changes in effluent ammonia concentration, concentration of gas phase ammonia has volatility, but the volatility is not high and the effluent ammonia concentration is in the range of 0.030-0.166mg/L. Liquid phase ammonia concentration is also fluctuate but the fluctuation is little and effluent ammonia concentration is in the range of 0.030-0.165mg/L. In the meantime, experiment also examines the change of ammonia concentration along the column direction and its experiment results is that gas phase ammonia is gradually reduced, while liquid phase ammonia is then gradually increased.Paper continues to study bubble column experiment with the same flow and the experiment results show that bromate inhibition rate of gas phase ammonia is 60%-71%, while bromate inhibition rate of liquid phase ammonia (ammonium sulfate) is 55%-62%. Compared with the bromate generated by liquid phase ammonia, the bromate generated by gas phase ammonia is reduced by 20%-32%. So gas phase ammonia has a better bromate inhibition effect than that of liquid phase ammonia. Without changing the other conditions, increasing ammonia concentration, inhibition effect of bromate by gas phase ammonia and liquid phase ammonia are both enhanced; increasing concentration of bromide ion and ozone respectively, bromate inhibition rate of gas phase ammonia and liquid phase ammonia has been lower, but drop a little. If the ozone concentration is unchanged while concentration of bromide ion and ammonia is changed, that is N / Br is unchanged, bromate inhibition effect in this condition has not regularity. For the effluent ammonia concentration, its magnitude of change is not large. Generally, the effluent ammonia concentration of gas phase ammonia is lower than that of liquid phase ammonia. Ammonia concentration change along the bubble column direction is first increased and then decreased for gas phase ammonia, while liquid phase ammonia is gradually increased.Based on the above results, we can conclude that gas phase ammonia inhibition effect on the bromate is better than that of liquid phase ammonia in the direction of water intake using the same way. Compared with the bromate generated by liquid phase ammonia, the bromate generated by gas phase ammonia is reduced by 20% -32%. Gas phase ammonia can be controlled by regulating the flow of ammonia dosage, so that it can achieve on-line control in the actual project.