Buffered Iron Slurry for Wastewater Sulfide Control

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Solution Overview

Problem

Current methods for controlling hydrogen sulfide in wastewater collection systems, such as iron salt solutions, are hazardous and impractical for smaller tributary segments in residential and commercial areas, leading to increased costs and safety concerns, while alternative solutions like oxygen injection and nitrate treatments are inefficient or costly.

Innovation Solution

A non-hazardous iron product is developed, comprising a slurry of Fe2+ and Fe(OH)2, produced with minimal alkali hydroxides, using sodium bisulfite and sodium carbonate to create a stable, cost-effective solution that effectively neutralizes sulfides in wastewater, reducing storage and handling issues.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If iron salt solutions are used to control hydrogen sulfide in wastewater, then sulfide binding efficiency is improved, but safety hazards and storage requirements worsen

Engineering Contradiction:

Improvesulfide binding efficiencyVSAvoidsafety hazards

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the chemical form of iron from hazardous concentrated salt solutions to a stable slurry form with controlled pH (maintained between 3-4 using buffers like sodium bicarbonate). This parameter change maintains sulfide binding efficiency while eliminating safety hazards associated with concentrated iron salts, allowing safe storage and handling without specialized facilities

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention creates a composite slurry system combining iron salts with buffers (sodium bicarbonate, sodium citrate) and stabilizers. This composite approach maintains the sulfide-binding capability of iron while the buffer components neutralize harmful effects and provide stability, resulting in a non-hazardous material that can be stored and handled safely

Inventive Principle:

Principle #40Composite materials

2Reliability

If iron salt solutions are used for wastewater treatment, then sulfide control is improved, but storage and handling complexity worsen

Engineering Contradiction:

Improvesulfide controlVSAvoidstorage and handling

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

By adjusting and controlling the pH parameter to remain between 3-4 through buffer systems, the iron product transitions from a highly reactive, unstable concentrated solution to a stable slurry that resists premature reaction with atmospheric oxygen and maintains sulfide binding capability. This enables simple storage in standard containers and easy handling without specialized infrastructure

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The slurry formulation includes buffers and stabilizers that automatically maintain pH and prevent degradation without requiring active monitoring or control systems. The product is self-stabilizing, eliminating the need for complex storage facilities, temperature control, or specialized handling procedures

Inventive Principle:

Principle #25Self-service

3Reliability

If conventional iron salt solutions are used, then sulfide neutralization is effective, but cost increases due to storage facility requirements

Engineering Contradiction:

Improvesulfide neutralizationVSAvoidcost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

Changing the physical form from concentrated solution to buffered slurry and controlling pH to 3-4 eliminates the need for expensive hazardous material storage facilities, specialized handling equipment, and trained personnel. The product can be manufactured, stored, and applied using conventional, low-cost infrastructure while maintaining effective sulfide neutralization

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The stable slurry formulation allows use of simple, inexpensive packaging and storage containers rather than expensive hazardous material infrastructure. The product can be manufactured locally or on-site, reducing transportation and storage costs, making it economically viable for small tributary segments

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

4Reliability

If smaller tributary segments in residential areas are treated with conventional methods, then sulfide control is achieved, but practicality worsens due to hazardous storage requirements

Engineering Contradiction:

Improvesulfide controlVSAvoidpracticality

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

By transforming the iron product into a stable, buffered slurry with controlled pH and reduced reactivity, the invention enables deployment in residential and commercial areas where hazardous material storage is prohibited or impractical. The product adapts to small tributary segments by eliminating infrastructure requirements while maintaining sulfide control effectiveness

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The self-stabilizing slurry formulation with built-in buffers and stabilizers requires no specialized storage facilities, temperature control, or handling expertise. This makes the solution practically applicable in residential areas where infrastructure is limited and regulations prohibit hazardous material storage, enabling widespread adoption

Inventive Principle:

Principle #25Self-service

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

The solution provides a stable, cost-effective means to control hydrogen sulfide in wastewater, maintaining sulfide binding efficiency and reducing infrastructure corrosion, suitable for residential and commercial zones without the need for hazardous chemical storage facilities.

Implementation Method 1

adding an amount of sodium hydroxide to the aqueous solution to increase the pH of the aqueous solution to between 2-2.5

Methodology Applied

Scientific EffectpH adjustment:

Implementation Method 2

determining an amount of sodium bicarbonate and adding the identified amount of sodium bicarbonate to the aqueous solution, wherein the sodium bicarbonate adjusts the pH of the aqueous solution to a desired pH

Methodology Applied

Scientific EffectpH adjustment:

Implementation Method 3

providing a buffer to the aqueous solution to generate a slurry

Methodology Applied

Scientific Effectbuffering:

Implementation Method 4

adding sodium bisulfite to a solution comprising iron, creating an aqueous solution

Methodology Applied

Scientific Effectchemical reaction: Chemical Bonding

Data Source

PatentUS20230042185A1Creation of an iron product for wastewater treatment

Publication Date: 2023.02.09 U S PEROXIDE LLC

AI summary

An embodiment provides a method for making a non-hazardous iron product for treating wastewater, including: adding sodium bisulfite to a solution comprising iron, creating an aqueous solution; adding an amount of sodium hydroxide to the aqueous solution to increase the pH of the aqueous solution to between 2-2.5; determining an amount of sodium bicarbonate and adding the identified amount of sodium bicarbonate to the aqueous solution, wherein the sodium bicarbonate adjusts the pH of the aqueous solution to a desired pH; and providing a buffer to the aqueous solution to generate a slurry. Other embodiments are described and claimed.