Monochloramine Injection Suppresses Bromate in Groundwater AOP
Solution Overview
Problem
Advanced oxidation processes (AOPs) used to remove 1,4-dioxane from water produce bromate, a suspected human carcinogen, when bromide ions are present, necessitating a reduction in bromate formation.
Innovation Solution
The controlled injection of monochloramine into the influent line of groundwater, prior to hydrogen peroxide and ozone treatment, suppresses bromate formation while effectively destroying 1,4-dioxane. Additionally, removal of iron with a sand filter further reduces bromate production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If advanced oxidation processes (AOPs) using ozone and hydrogen peroxide are used to remove 1,4-dioxane from groundwater, then 1,4-dioxane destruction is effective, but bromate is formed as a harmful byproduct
Solution Approach 1:
Monochloramine is injected into the groundwater before the oxidation process begins. This preliminary addition of monochloramine modifies the chemical environment in advance, creating conditions that favor 1,4-dioxane destruction while suppressing bromate formation during the subsequent oxidation process
Solution Approach 2:
Monochloramine acts as an intermediary substance that mediates between the oxidants (ozone and hydrogen peroxide) and the contaminants. It provides an alternative oxidation pathway that destroys 1,4-dioxane without generating bromate, thus serving as a protective intermediary in the chemical reactions
2Object-generated harmful factors
If monochloramine is injected into the influent line before oxidation treatment, then bromate formation is suppressed, but process complexity increases
Solution Approach 1:
The invention changes the chemical parameter composition of the treatment process by introducing monochloramine in addition to the standard oxidants. This parameter change (adding a third chemical component) modifies the reaction dynamics to suppress bromate while maintaining effectiveness against 1,4-dioxane
3Object-generated harmful factors
If iron is present in groundwater subjected to AOP treatment, then iron removal is needed, but additional treatment steps increase process complexity
Solution Approach 1:
The sand filter is positioned in the treatment train to remove iron from the groundwater before it enters the oxidation contactors. This preliminary iron removal prevents iron-catalyzed bromate formation during the oxidation process, addressing the problem before it can occur
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach significantly reduces bromate formation to levels of 1-3 ppb, achieving effective destruction of 1,4-dioxane while minimizing the production of harmful bromate compounds.
Implementation Method 1
a closely controlled injection of monochloramine into the influent line of ground water that has been subjected to the oxidant hydrogen peroxide and prior to subjecting the treated effluent to an injection of the oxidant ozone suppresses the formation of bromate while destroying 1,4-dioxane
Implementation Method 2
Advanced oxidation processes (AOPs) are chemical treatment procedures designed to remove organic, and sometimes inorganic, materials in water and wastewater by oxidation through reactions with hydroxyl radicals
Implementation Method 3
If iron is present the ground water, removal of the iron from the treated effluent with a sand filter further reduces the production of bromates
Data Source
AI summary
An improved method for removing contaminants, such as 1,4 dioxane, from ground water using an advance oxidation process. The improved method uses a controlled injection of monochloramine into the effluent in an amount that suppresses formation of bromates but does not interfere with the oxidative destruction of 1,4 Dioxane destruction. Removing iron from the effluent with a sand filter further improves the removal of bromates from the treated water.