Wastewater Infrastructure Challenges in U.S. Wastewater Infrastructure

Thioguard ® TST A common sense solution to a billion dollar problem.

The American Society of Civil Engineers (ASCE) has reported to Congress and the Senate… American wastewater systems currently require $12 billion* a year more than available funds to replace and failing infrastructure. aging And the shortfall is increasing every year… *American Society Of Civil Engineers “U.S. Water Infrastructure Needs” 3/28/01

However… Compared with roads and bridges, aging is not the underlying problem in this case.

In 1977 the clean water act* increased treatment requirements for municipal wastewater. *Recommended by ASCE

The result has quietly cost U.S. taxpayers billions of dollars. This legislation has contributed to subtle changes in wastewater chemistry which increased sulfide production across the country. The result has quietly cost U.S. taxpayers billions of dollars.

Wastewater has changed. It’s become more corrosive. Today, wastewater infrastructure is subject to much more corrosion than before 1980. Data courtesy of the City of L.A., CA More Corrosion Data provided by the City of Los Angeles

Sulfide gas is converted to corrosive sulfuric acid on surfaces inside sewers. This acid dissolves concrete and metal.

That’s why, in 2000 the EPA estimated municipal sewers subject to corrosion were failing six times faster than the rate they’re being repaired.

By 2016 the EPA now expects more than 50% of the country’s 600,000 miles of major sewer lines will be in poor, very poor or inoperable condition. Tucson, Arizona

Acid corrosion is the problem. Here’s how it happens…

Bacteria in the wastewater consume oxygen. Sewer When the dissolved oxygen concentration falls below 0.1 mg/l, the water becomes septic. Other bacteria present in the water convert sulfates to sulfides. This causes the rotten egg smell, hydrogen sulfide gas (H2S). Bacteria in the wastewater consume oxygen. H2S Gas H2S Gas H2S Gas H2S Gas Wastewater O2 O2 pH ~ 7 D.O.<0.1 mg/l Bacteria O2

In water at pH 7, about 50% of the dissolved sulfide converts to H2S gas.

And virtually nothing is being done to stop it from happening. Thiobacillus On the surfaces above the water, H2S gas is converted to strong sulfuric acid by Thiobacillus bacteria. And virtually nothing is being done to stop it from happening. This acid corrosion, not “aging”, then dissolves the infrastructure. Acid Attacks Concrete H2S + O2 = H2SO4 SO42- HS- H2S

Once rebar is exposed, the sewer is structurally compromised. Collapses routinely occur when preventable corrosion is allowed to continue unchecked. Acid Attacks Concrete H2S + O2 = H2SO4 SO42- HS- H2S

Hydrogen sulfide corrodes cast iron pipe, valves and fittings:

Hydrogen Sulfide corrodes cast concrete sewer mains:

Hydrogen sulfide corrodes manhole and wet well structures:

Resulting in SSO’s, disruptive flows and expensive emergency repairs:

How could this happen? Widespread corrosion is “relatively” new and although much faster today, it still happens gradually. Structural problems and collapses take years to develop. (But they are happening regularly now.) Few wastewater professionals really recognize and understand the extent of the problem.

How could this happen? When odors or sewer collapses draw public attention, engineering consulting firms tend to recommend capital intensive solutions. (See the ASCE reports to congress where, for example, the problem is incorrectly presented as aging infrastructure instead of corrosion.)

The rate of corrosion can be assessed with a simple surface pH test.

Corrosive conditions are the problem and that can easily be detected using a simple, inexpensive surface pH test.

Surface pH tells the whole story…

Red is bad, green is good. 7= Neutral Above 7 = Basic Below 7 = Acidic

Red is bad, green is good.

(2” of sacrificial concrete) Source L.A.County San District 0.001 0.01 0.1 1.0 Corrosion Rate (in./year) 7 6 5 1 pH Corrosion Range 4 3 2 0.25 Years of Life (2” of sacrificial concrete) 200 years 100 50 20 Surface

Sewer design life is generally based on 100 years of useful service. Surface pH ≥ 4; Life Cycle = 100 yrs

Surface pH ≥ 4; Life Cycle = 100 yrs Source L.A.County San District 0.001 0.01 0.1 1.0 Corrosion Rate (in./year) 7 6 5 1 pH Corrosion Range 4 3 2 0.25 100 years of useful life 4 200 100 50 20 8 Years of useful life

1250% When the surface pH falls below four, sewer life cycle costs increase exponentially… For example, the difference in annual cost between surface pH 4 and 2 is…

>200 years of corrosion life 7 Source L.A.County San District 0.001 0.01 0.1 1.0 Corrosion Rate (in./year) 7 6 5 1 pH Corrosion Range 4 3 2 0.25 6 5 100 years of useful life 4 3 8 years 2 200 100 50 20 8 Source L.A.County San District Years of useful life

Surface pH of two or lower is now common. But most cities (or consulting firms) don’t measure for it.

The value of U.S. sewers is estimated to be over $1 Trillion*. Why is this important? The value of U.S. sewers is estimated to be over $1 Trillion*. *Wade, Mark, “ Controlling Inflow and Infiltration In Wastewater Collection Systems”,

About 10% are large diameter (>18”) which are subject to corrosion. These sewers alone are worth more than $100 billion.

Surface pH ≥ 4; Life Cycle = 100 yrs Simple Life Cycle Cost; $100 Billion/100yrs = $ 1 Billion/yr

But if the pH is allowed to fall… Surface pH 2.0; Life Cycle = 8 yrs Simple Life Cycle Cost; $100 Billion/8yrs = $12.5 billion/yr

That’s $11.5 billion/yr caused by preventable corrosion, not . $ 12.5 billion - $1 billion = That’s $11.5 billion/yr caused by preventable corrosion, not . aging

According to the American Society of Civil Engineers – “Standard operating practices must change.” “New solutions are needed.”

Thioguard is a simple new solution to this billion dollar problem.

Total System Treatment Thioguard® TST Total System Treatment A practical, non-hazardous, system-wide strategy for cost effective management of odor and corrosion in wastewater collection and treatment networks.

Thioguard is industrial strength milk of magnesia. Thioguard neutralizes the acid processes that cause sewer corrosion. Thioguard is a registered trademark of Premier Chemicals and is patented for use in municipal collection systems under U.S. patent numbers 5,718,944 - 5,833,864 - 5,554,355 - 5,834,075, 6,056,997

Corrosion which limits system life expectancy Thioguard

And it improves wastewater treatment at the plant. Thioguard ® TST And it improves wastewater treatment at the plant. Biological Treatment Secondary Clarifier Digestion Effluent Conditioning Dewatering Primary Collection System Disinfection Primary Treatment Collection System Secondary Clarifier Biological Treatment Disinfection Effluent Digestion Conditioning Dewatering Biosolids

Recall this slide showing the relationship between wastewater pH and hydrogen sulfide gas? SO42- HS- H2S H2S Gas

The red area represents how much gas is produced in this example. The amount of gas produced is affected by the wastewater pH. Higher pH = less gas. Here’s what Thioguard does. > 80% Reduction H2S Gas Wastewater

Twenty gallons of Thioguard added to one million gallons of wastewater reduces corrosion by over 80%. The cost to treat 10% of the entire U.S. wastewater flow is less than $50 million/year.

Corrosion Rate Vs. Wastewater pH Without Thioguard Corrosion > 80% Less Corrosion With Thioguard

Total System Treatment Thioguard ® TST Total System Treatment Added directly to wastewater Thioguard stops odors, corrosion and grease buildup that cause blockages and sewer failures. And Thioguard is environmentally safe and improves wastewater treatment and discharge water quality.

What color is your system? Red is bad, green is good. What color is your system?

Thioguard ® TST A common sense solution to a billion dollar problem.

Thioguard ® TST