Presentation on theme: "Wastewater Infrastructure"— Presentation transcript:
1Wastewater Infrastructure Challenges in U.S.Wastewater Infrastructure
2Thioguard ®TSTA common sense solution to a billion dollar problem.
3The 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.agingAnd the shortfall is increasing every year…*American Society Of Civil Engineers“U.S. Water Infrastructure Needs” 3/28/01
4However…Compared with roads and bridges, aging is not the underlying problem in this case.
5In 1977 the clean water act* increased treatment requirements for municipal wastewater. *Recommended by ASCE
6The 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.
7Wastewater 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., CAMore CorrosionData provided by the City of Los Angeles
8Sulfide gas is converted to corrosive sulfuric acid on surfaces inside sewers. This acid dissolves concrete and metal.
9That’s why, in 2000 the EPA estimated municipal sewers subject to corrosion were failing six times faster than the rate they’re being repaired.
10By 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
11Acid corrosion is the problem. Here’s how it happens…
12Bacteria in the wastewater consume oxygen. SewerWhen 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 GasH2S GasH2S GasH2S GasWastewaterO2O2pH ~ 7D.O.<0.1 mg/lBacteriaO2
13In water at pH 7, about 50% of the dissolved sulfide converts to H2S gas.
14And virtually nothing is being done to stop it from happening. ThiobacillusOn 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 AttacksConcreteH2S+ O2 = H2SO4SO42-HS-H2S
15Once rebar is exposed, the sewer is structurally compromised. Collapses routinely occur when preventable corrosion is allowed to continue unchecked.Acid AttacksConcreteH2S+ O2 = H2SO4SO42-HS-H2S
16Hydrogen sulfide corrodes cast iron pipe, valves and fittings:
18Hydrogen sulfide corrodes manhole and wet well structures:
19Resulting in SSO’s, disruptive flows and expensive emergency repairs:
20How 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.
21How 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.)
22The rate of corrosion can be assessed with a simple surface pH test.
23Corrosive conditions are the problem and that can easily be detected using a simple, inexpensive surface pH test.
27(2” of sacrificial concrete) Source L.A.County San District0.0010.010.11.0Corrosion Rate (in./year)7651pHCorrosion Range4320.25Years of Life(2” of sacrificial concrete)200 years1005020Surface
28Sewer design life is generally based on 100 years of useful service. Surface pH ≥ 4; Life Cycle = 100 yrs
29Surface pH ≥ 4; Life Cycle = 100 yrs Source L.A.County San District0.0010.010.11.0Corrosion Rate (in./year)7651pHCorrosion Range4320.25100 years of useful life420010050208Years of useful life
301250%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…
31>200 years of corrosion life 7Source L.A.County San District0.0010.010.11.0Corrosion Rate (in./year)7651pHCorrosion Range4320.2565100 years of useful life438 years220010050208Source L.A.County San DistrictYears of useful life
32Surface pH of two or lower is now common. But most cities (or consulting firms)don’t measure for it.
33The 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”,
34About 10% are large diameter (>18”) which are subject to corrosion. These sewers alone are worth more than $100 billion.
35Surface pH ≥ 4; Life Cycle = 100 yrs Simple Life Cycle Cost;$100 Billion/100yrs = $ 1 Billion/yr
36But 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
37That’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, notaging
38According to the American Society of Civil Engineers – “Standard operating practices must change.”“New solutions are needed.”
39Thioguard is a simple new solution to this billion dollar problem.
40Total System Treatment Thioguard® TSTTotal System TreatmentA practical, non-hazardous, system-wide strategy for cost effective management of odor and corrosion in wastewater collection and treatment networks.
41Thioguard 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, ,833, ,554, ,834,075, 6,056,997
42Corrosion which limits system life expectancy Thioguard
43And it improves wastewater treatment at the plant. Thioguard ®TSTAnd it improves wastewater treatment at the plant.BiologicalTreatmentSecondaryClarifierDigestionEffluentConditioningDewateringPrimaryCollectionSystemDisinfectionPrimaryTreatmentCollectionSystemSecondaryClarifierBiologicalTreatmentDisinfectionEffluentDigestionConditioningDewateringBiosolids
44Recall this slide showing the relationship between wastewater pH and hydrogen sulfide gas? SO42-HS-H2SH2S Gas
45The 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% ReductionH2S GasWastewater
46Twenty 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.
47Corrosion Rate Vs. Wastewater pH Without ThioguardCorrosion> 80% Less CorrosionWith Thioguard
48Total System Treatment Thioguard ®TSTTotal System TreatmentAdded directly to wastewater Thioguard stops odors, corrosion and grease buildup that cause blockages and sewer failures.AndThioguard is environmentally safe and improves wastewater treatment and discharge water quality.
49What color is your system? Red is bad, green is good.What color is your system?
50Thioguard ®TSTA common sense solution to a billion dollar problem.