A process is disclosed for treating water, such as wastewater, with ozone under alkaline and acidic conditions to decompose and remove acrolein and acrolein byproducts from the water and/or wastewater. The process is able to lower the concentration of acrolein and acrolein byproducts from water to a sufficiently low level suitable for discharge to a municipal sewer collection system with reduced occurrence of the decomposition by-products of acrolein converting back to acrolein in the water. One embodiment of the process treats contaminated water containing acrolein with ozone by sparging or bubbling ozone through the contaminated water. The contaminated water can be treated with ozone where the contaminated water is initially adjusted to a pH greater than 7.0 for a time to convert at least a portion of the acrolein to 3-hydroxypropanal to obtain a partially treated water. The pH of the partially treated water is then adjusted to a pH below 7.0 while continuing the ozone treatment for a time sufficient to react with and decompose the 3-hydroxypropanal to inhibit the conversion of 3-hydroxypropanal back to acrolein.