Wastewater Odor & Corrosion Control

Reduce odor, corrosion & maintenance.

It is well known that highly oxic conditions support rapid oxidation of H2S and other reduced sulfur compounds present in wastewaters.

As long as oxic conditions are maintained, H2S formation is prevented. Therefore successful oxygen transfer technology would significantly lessen capital outlay and provide many extra years of infrastructure usefulness. However, until recently serious difficulties were encountered in trying to dissolve high levels of pure oxygen into raw wastewater. The Speece Cone by ECO2 was designed to perfect this process.

Collection Systems

Eliminate Hydrogen Sulfide

Corrosion Control

Where there is odor, there is corrosion. When gaseous H2S reaches the surface of the sewer infrastructure, Thiobacillus Thiooxidans bacteria oxidize H2S to sulfuric acid (H2SO4), which quickly and tenaciously corrodes concrete and steel.

Eliminate Sulfides

According to the ASCE Manual for manhole rehab, H2S concentrations of 20ppm corrode concrete at a rate of 1 inch per 5 years. It is therefore crucially important to not just reduce sulfide concentrations, but to eliminate the formation of sulfides, in order to achieve effective corrosion control.

ECO2 has proven for many years the ability to reliably reduce H2S to near non-detect levels to protect your infrastructure from corrosion damage.

Wastewater Odor & Corrosion Control

Force Main Odor Control

The ECO2 SuperOxygenation Technology prevents your sewage from going septic. By effectively dissolving a sufficient amount of oxygen into the force main, the ECO2 SuperOxygenation System maintains aerobic conditions, under which the formation of sulfides (H2S) is prevented.

Untreated H2S Levels

Average: 145 ppm

Laguna Beach Graph

Proven Technology

ECO2 has proven this concept time and time again. No matter how high H2S concentrations are at the discharge of a force main, where the ECO2 technology is a fit, it will eliminate sulfides and H2S at a fraction of the cost of conventional chemicals. ECO2‘s oldest 3 installations on force mains have been in operation since 2003 and are still providing reliable odor & corrosion control today.

Treated H2S Levels

Average: 0.4 ppm

Laguna Beach Graph 2

Robust Design

ECO2 Systems distinguish themselves through robust design with few moving parts and wide openings, capable of passing raw wastewater. Our non-pressurized systems have the lowest operating costs on the market.

Sulfide Oxidation with Time

Gravity Systems

A gravity system naturally limits the amount of oxygen that can be added to the water. This is where ECO2‘s years of experience come into play in determining the best points of application for oxygen.

Technology At Work

The ECO2 Technology works equally well in gravity systems as in force mains. A great way to apply dissolved oxygen to gravity collection systems is shortly upstream of the odor release point. Low levels of dissolved oxygen can be used to oxidize and remove existing sulfides from the water before they can strip out as H2S in sensitive areas.

With ECO2 there’s no risk for effervescence. Our side stream systems operate under low pressure and do not supersaturate to a point where spontaneous off-gassing of pure oxygen would occur.

Headworks & Primary Clarifiers

Strategically placed upstream of the headworks, an ECO2 System can remove sulfides from the influent wastewater, preventing H2S stripping and the associated odor and corrosion at the headworks.

Wastewater Treatment Processes

Prevention Is Better Than Cure

Let’s face it: headworks equipment is expensive and to expose it to high H2S concentrations is irresponsible. While air scrubbers may address the odor before it gets outside, H2S is still in the air and around your equipment inside. So why not remove sulfides before they get to the plant, prevent odors AND corrosion, while also lowering your oxygen demand for dissolved sulfides upstream of your aeration basins.


Primary Clarifier Odor & Corrosion Control

ECO2‘s low pressure side stream SuperOxygenation System can effectively keep primary clarifiers aerobic and free from H2S without upsetting the settling cycle.

Reduce Existing, Prevent New Sulfides

Primary clarifiers are often a significant source of odors at wastewater treatment plants. Naturally occurring dissolved oxygen is consumed quickly during the settling process and sulfides are produced as the water goes septic.

H2S is released when the water flows over the effluent weirs. Adding dissolved oxygen helps reduce existing sulfides and prevents the formation of new sulfides during the settling process. ECO2 is an inexpensive alternative to covering and scrubbing the primary clarifiers.

Anson Madison ECO2
Anson Madison, ME. ECO2 SuperOxygenation Installation

Sludge Tanks & Transfer Lines

Control Odors and Corrosion in Sludge Holding Tanks

Preventing Odors & Corrosion

High levels of hydrogen sulfide (H2S) exist in Primary and Waste Activated Sludge. This presents a problem in the sludge holding tanks and solids handling facilities, where the H2S gas causes foul odors and equipment deterioration due to its highly corrosive properties.


The ECO2 sludge treatment alternative involves adding a small amount of high purity oxygen on a sidestream, using a Speece Cone and a process called SuperOxygenation. Although sludge has a very high oxygen demand, the reaction to oxidize H2S has a much faster rate of oxygen demand than that of carbonaceous BOD.

SuperOxygenation can be used to maintain micro-aerophilic conditions (D.O. near zero) in the sludge, by supplementing dissolved oxygen (D.O.) at a rate less than the total uptake rate.

In this environment, the biological conversion of H2S stops at elemental sulfur rather than being oxidized all the way to sulfate, resulting in a low cost, low maintenance method for eliminating the odorous and corrosive H2S compounds common to all wastewater sludge holding tanks and solids handling facilities.

ECO2 System Design
ECO2 - Primary Clarifier Odor Control

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