Advanced chloramine reduction technologies for water treatment using LED photolysis and electrochemical oxidation

Overview

This research addresses the challenge of removing combined chlorine (chloramines) from drinking water to concentrations below 100 ppb using two compact, small-footprint treatment technologies. The first approach uses a tunable LED reactor that targets the specific photon wavelengths matching the peak absorptivity of mono-, di-, and tri-chloramine species, enabling efficient direct photolysis primarily into chloride and ammonia. The second approach employs a flow-through electrochemical cell with a Ti4O7 (titanium suboxide) anode and stainless-steel cathode that indirectly oxidizes chloramines through hydroxyl radical generation. Both methods are being evaluated for their ability to provide precise control over reaction conditions, minimize undesirable byproducts, and deliver superior economic value compared to conventional chloramine management approaches.

Technical specifications

LED photolysis reactor:

• Small-footprint design with photon wavelength tuning capability
• Uses an array of LEDs aligned with peak absorptivity of mono-, di-, and tri-chloramine
• Degrades chloramines via direct photolysis into chloride and ammonia
• Allows dosage control through photon intensity adjustment

Electrochemical reactor:

• Stack or flow-through cell configuration
• Ti4O7 anode paired with stainless-steel cathode
• Indirect oxidation of chloramines via hydroxyl radical generation
• Enables precise control over reactivity and byproduct formation
• Expected to offer better economic value than the LED system

Experimental evaluation parameters:

• Influent flow rates
• Influent chloramine concentrations
• Feed water temperatures
• Photon or electrical dosage levels
• Total chloramine and byproduct measurement using in-house analytics

Technology readiness level

This research is at an early stage, with the underlying technologies identified as promising small-footprint treatment methods but with relatively unknown reaction rates, byproduct profiles, and energy consumption characteristics. Future validation will involve bench-scale experiments using tap water as the feed source, systematically varying flow rates, chloramine concentrations, temperatures, and dosage levels. The anticipated project timeline is approximately two years, though flexible. The team is currently seeking personnel support and supplies to advance the research. No prior validation procedures have been completed, and the project represents an opportunity for collaborative development and optimization of these water treatment approaches.