Electrochemical destruction of chloramines using magneli phase titanium oxide electrodes

Overview

This solution uses Magneli phase titanium oxide (Ti4O7) electrodes to electrochemically destroy chloramines in drinking water, eliminating the need for chemical dechlorination or breakpoint chlorination. Chloramines are widely used as secondary disinfectants in municipal water systems but create challenges for utilities, including taste and odor complaints, nitrification in distribution systems, and difficulty in removal prior to discharge. The technology offers a rapid, electrically driven treatment approach that can be tuned based on influent chloride levels, producing only benign end products such as nitrogen gas, chloride, and nitrate.

Technical specifications

Key features:

• Magneli phase Ti4O7 electrodes provide high electrochemical activity and durability for water treatment
• In low-chloride waters, the system oxidizes ammonia to nitrate while releasing inorganic chloride
• In high-chloride waters, the system oxidizes chloride to free chlorine, which then converts chloramines to nitrogen gas
• A paired reducing electrode step can eliminate any residual free chlorine produced during oxidation
• Long-term electrochemical testing has demonstrated rapid ammonia oxidation to below detection limits
• Kinetics of chloride oxidation and formation of oxidized species have been characterized
• System design can be tailored to local water quality parameters, particularly background chloride concentration

Technology readiness level

The technology is at an advanced research and validation stage. The UMass WET Center research group has conducted extensive long-term electrochemical testing of Magneli phase electrodes for contaminant destruction, oxidant production, and mineralization. Ammonia oxidation to below detection limits has been demonstrated, along with characterization of chloride oxidation kinetics. Next-stage validation will test electrode performance across a range of drinking water qualities, spanning chloride levels typical of potable supplies, and will optimize a two-stage oxidizing/reducing electrode configuration. The work is positioned to deliver a targeted electrode system design suitable for pilot-scale evaluation by water utilities and treatment technology partners.