Effect of Preozonation on the Formation of Chlorinated Disinfection By‐products for River Ruhr

The purpose of the study is to gain a better understanding about the formation of THM (trihalomethanes), HAA (haloacetic acids), and AOX (adsorbable organic halogen) in river water (river Ruhr, Essen) through a chlorination kinetics approach. The effect of chlorination time and preozonation on the formation of THM, HAA, and AOX substances was studied. Preozonation can reduce the chlorine demand and the precursors for AOX and THM. THM generation was reduced further, when the ozone dosage consumed increased from 3.5 to 12.5 mg in the 1.4 L reaction vessel. AOX and TCAA (trichloroacetic acid) concentrations also decreased dramatically when 3.5 mg of ozone had reacted with the river water, but a higher dose of ozone did not further reduce AOX and TCAA formations. Besides, the characteristics of organic matter in raw water, ozonated water, and preozonated/chlorinated water was investigated. The results suggest the formation of low‐molecular‐weight acids with low UV absorbance when high‐molecular refractive matter is oxidized.     

Determination of trihalomethanes and the ionic composition of groundwater at Amman City, Jordan

A water-chemistry evaluation was made of the available springs and wells in Amman and vicinity. Trihalomethanes (THM) were found in all analysed samples with concentrations ranging from 0.2–31.88 μg/L. The probable sources of trihalomethanes in the aquifers originate from three sources: (1) chlorinated Deir Alla surface water, (2) reaction of excess chlorine in the leaky, corroded water-distribution network with organic matter in the vadose zone, and (3) sewage seepage from cesspools in the area. Total organic carbon (TOC) ranged from 0.2–1.4 mg/L. Its probable source is either from the vadose zone or the treated surface water at Deir Alla. It was found that TOC was of vital importance in the formation of THM in the presence of chlorine from the water-distribution system. Major ionic composition of the analysed samples reflected the limestone lithology of the aquifer in the investigated area. Heavy-metal content was relatively low due to the high pH of the groundwater samples. Electronic Publication