AWWA ACE61659

Experiments were performed in the presence and absence of background ammonia tostudy the significance of the direct reaction(s) of monochloramine (NH₂Cl) with dissolvedorganic matter (DOM) in the haloacetic acid (HAA) formation during chloramination. Directreactions were found to play a major role in the HAA formation compared to the reactions ofNH₂Cl decomposition products (i.e., hypochlorous acid and dichloramine) with DOM.Dihalogenated HAAs (DXAA) constituted the major HAA₉ species formed duringchloramination. The extent of DXAA formation decreased with increasing pH. Experimentsconducted with sodium sulfite (Na2SO3) and ammonium chloride (NH4Cl) showed that selectionof quenching agent is important to obtain reliable results from chloramination kineticexperiments. When preformed chloramines are employed, the use of NH₄Cl, the quenchingagent recommended by USEPA Method 552.3 for HAA samples, may result in false high HAAconcentrations at early reaction periods. The type of quenching agent used in different studiesappears to be the cause of different kinetic patterns reported for chloramination kinetics in theliterature. Includes 16 references, tables, figures.

Product Details

Edition:

Vol. - No.

Published:

06/17/2005

Number of Pages:

16

File Size:

1 file , 1.2 MB