Transcript In Plant Benefits - Presentation

Thioguard ®
TST
A common sense solution for wastewater management
October 28, 2005
It is an environmentally
safe, or
less
expensive
Produced
from natural deposits
extracted
from
replacement
foriscaustic
soda
that
provides
many
seawater,
Thioguard
solves
many
of
the
problems
Thioguard
Mg(OH)
,
milk
of
magnesia.
2
valuable
benefits
in
wastewater
collection
facing wastewater professionals
today. and
treatment.
Mg(OH)2
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
We’re an industry
leader in the
production and
application of
Magnesia Specialty
Chemicals.
Premier has been
in the business for
over 50 years.
Premier Chemicals
Locations
Headquarters
Philadelphia, PA
Manufacturing Facilities
 Port St. Joe, FL
 Gabbs, NV
 Brownsville, TX
 York, PA
Toll Manufacturing
 Santa Fe Springs, CA
 Phoenix, AZ
 New Bern, NC
Sales Office
Cleveland, Ohio
Thioguard ®
TST
Biological,
The Culmination
Chemical
of and
20 Years
Bio-chemical
of Magnesia
Interactions
Field Application
and Mechanisms
and
Research in Wastewater Treatment
In general, municipal wastewater treatment plants and
collection systems operate better under proper, stable pH
with lower acidity and adequate alkalinity.
Alkalinity contributes to the properties of wastewater, many
of which positively affect the physical, biological and
chemical processes required for treatment.
For example…
Nitrification
Every molecule of ammonia-N requires one
molecule of alkalinity.
1 mg/L NH4-N
= 7.14 mg/L CaCO3
= 5.50 mg/L NaOH
Acidity, Alkalinity & pH
The term “pH” stands for the
“power of Hydrogen”
pH is a measurement of the free hydrogen ion
in a solution.
pH = -log [H+]
pOH = -log[OH-]
pH + pOH = 14
Commercial Sources of Alkalinity (OH-)
Na, Ca, Mg and K
1A
Monovalent
1
H
Divalent
2A
NaOH
KOH
3 4
Li Be
Mg(OH)2
Ca(OH)2
Sodium AN 11, AM 22.989
11 12
Na Mg
Magnesium AN 12, AM 24.312
Potassium AN 19, AM 39.102
19 20
K Ca
Calcium AN 20, AM 40.08
37 38
Rb Sr
Commercially Available Options
Caustic Soda – NaOH
Despite hazardous handling, environmental concerns, and wide price
fluctuations, it has been the most commonly used acid
neutralization reagent for industrial or municipal purposes. NaOH
has been favored for ease of application and soluble by-products.
Lime Slurry - Ca(OH)2
Commonly used for settling, alkalinity, metals removal, and biosolids
handling. Limited because of hazardous handling, equipment
requirements and insoluble by-products. Not recommended for
municipal wastewater addition.
Magnesium Hydroxide - Mg(OH)2
“Milk of Magnesia” is a safe, cost-effective alternative to caustic soda
and lime. Safer handling, better cost stability, soluble by-products
and measurable benefits increase its attractiveness for wastewater
applications compared with NaOH and lime.
Solubilities and Stoichiometry
For 50 mg/L Mg(OH)2 Equivalence:
2NaOH  2Na+ + 2OH2(40)g/mol  2(23)g/mol + 2(17)g/mol
Typical Dosage: 68.5 mg/L
100% Solubility  High pH triggers carbonate formation and bacterial kills
Ca(OH)2  CaOH+ + OH-  Ca+2 +
(74)g/mol
 (57)g/mol
2OH-
+ (17)g/mol  (40)g/mol + 2(17)g/mol
Typical Dosage: 63.5 mg/L
100% Solubility  High pH triggers carbonate formation and bacterial kills
Mg(OH)2  MgOH+ + OH-  Mg+2 +
(58)g/mol
 (41)g/mol
2OH-
+ (17)g/mol  (23)g/mol + 2(17)g/mol
Typical Dosage: 50 mg/L
18% Solubility  Moderate pH favors bicarbonate formation and bio-stability
Properties of Bases
Mg(OH)2 provides non-toxic, non-carbonate source of
slowly released (on demand) alkalinity
Property
% Hydroxide
Solubility (H2O, g/100ml)
Per million gallons
50% NaOH
30% Ca(OH)2
42.5
45.9
60.3
42
0.185
0.0009
1750 tons
60% Mg(OH)2
7.7 tons
75 lbs
Reactive pH
14
12.5
9.0
Freezing Point °F
61
32
32
1.37
1.25
1
Weight Equivalency
One Truckload of
50% Thioguard
1.37 Truckloads of
50% NaOH
1 Ton of Thioguard = 1.37 Tons of Caustic Soda
It’s not only less expensive, it provides many
benefits.
At say $400/ton,more
Thioguard
costs $292 on an
equivalent use basis.
Unlike other alkali choices, Thioguard contains
slowly dissolving Mg(OH)2 particles. These particles
have high surface pH and high surface area, but
relatively low solubility.
(Surface area = nearly 1 acre per gallon).
Undissolved magnesium hydroxide particles react
directly with H2S converting H2S to magnesium
polysulfide.
Slowly Dissolving
Mg(OH)2 Particle
Surface
High pH zone
~ 10.5
Nitrification
Every molecule of ammonia-N requires one
molecule of alkalinity.
1 mg/L NH4-N
= 7.14 mg/L CaCO3
= 5.50 mg/L NaOH
= 4.16 mg/L Mg(OH)2
Caustic Soda Addition
Because it is highly soluble, caustic
causes “HOT” zones near the addition
point.
pH distributions across a basin are less
stable and contribute to variability away
from optimal biological operating
conditions.
With Thioguard
With Thioguard, an even distribution of
alkalinity and pH balance provides a
bacteria friendly working environment.
®
Thioguard
Total System Treatment
Added directly to wastewater it stops odors,
corrosion and grease buildup (FOG) that cause
blockages (SSO’s), and sewer failures.
And
Magnesia is environmentally safe, saves chemical
costs, improves wastewater treatment and
discharge water quality.
Scrubbers/
Filters
ADD
THIOGUARD TST
AIR
Odors
Chemicals
Energy
Headworks
Bar Screen
Grit Chamber
Primary
Clarifier
Collection
System
Odors
Corrosion
Fats, Oils, Grease
Odors
Corrosion
Odors
Corrosion
Settling
FOG
WATER
Disinfection
Odors, Corrosion
Chemical Efficiency
UV Efficiency
Aeration Basin
Bio-Reactor
Effluent
SAR
Plant Efficiency
Secondary
Clarifier
Process
Efficiency
Capacity
Odors
Corrosion
Settling
FOG
Digestion
Typical Wastewater
When
added inConcerns
the collection system,
Treatment
Odors
Thioguard TST can reduce odors
and
Dewatering
corrosion system-wide and improve
Conditioning
Disposal
overall treatment plant performance.
Land Application
Odors
Corrosion
Process
Bio-Solids
Processing
SOLIDS
Benefits To The Plant

Odors
 FOG
 Loading control
 Aeration
 Foaming
 SVI (filaments)
 Effluent quality
 Clarifier denitrification

Inhibited nitrification
 Filter performance
 Chlorine demand
 Stable disinfection
 Improves digestion
 Biosolids handling and
disposal cost
 Energy cost

Without Thioguard






FOG Accumulation
Odors
Pin Floc
Floc Carryover
High MLSS
High VSS%

With Thioguard






Reduced FOG
Marked Odor Decrease
Better Clarification and
Settleability
Improved VSS Reduction
Increased Sludge Blanket
Density
Improved O2 Efficiency
Divalent Cation Bridging
• Negatively charged sites on exocellular
biopolymer are bridged by divalent cations
such as Ca2+ and Mg2+
• This bridging helps to stabilize and
strengthen the microbe-biopolymer floc
matrix
Mg2+ affects bioflocculation or
aggregation of microbes.
Divalent Cations Compete With Monovalent Ions
For Sites on Exocellular Biopolymers
+
+
+
+
+
+
+
+
Divalent Bridging Improves Floc Matrix
+
++
++
++
++
FOG
Floating on the water surface, low density FOG’s
are less accessible to bacteria for digestion.
Broken down into glycerols and organic salts by
Thioguard, FOG’s are more evenly distributed
throughout a body of water and more accessible
to bacteria.
NOTE: Excess pH during the saponification process can lead to
insoluble soap salts.
Saponification
Thioguard slowly releases
hydroxyl ions which
breakdown low-density,
OHlarge-chain fatty acids
(FOG) into glyerol and
Low-density,
long-chain fatty acids
various types of soap,
both
accumulate on the water surface
of which are more readily
and can
digested by bacteria of
in low velocity structures
OHbuild up on pipe walls causing
wastewater.
The soaps that are occlusion and eventually SSOs.
produced further facilitate
the breakdown of
accumulated blankets by
OHsolubilizing FOG’s.
TG HYDROXYL
CARBOXYLATE
SALTSIONS
- SOAP
O
||
RCO-
CH2
O
||
R’CO-
CH2
O
||
R”CO-
CH2
FATTY
GLYCEROL
ACID
FOG causes odor, increases
maintenance costs and
contributes to SSO’s.
Most systems require only 30 Gal/MGD for
adequate treatment.
90
80
%H2S Gas Reduction
70
60
50
40
30
20
10
0
0
10
20
30
40
Gallons Thioguard/Million Gallons Treated
50
American wastewater systems
currently require $12 billion* a year
more than available funds to replace
failing infrastructure.
And the shortfall is increasing every year…
*American Society Of Civil Engineers
“U.S. Water Infrastructure Needs” 3/28/01
In 1977 the clean water act increased
treatment requirements for municipal
wastewater.
This legislation required secondary
treatment and it has contributed to subtle,
but important changes in wastewater
chemical needs.
15
10
5
DISSOLVED SULFIDE
CONCENTRATION (mg/l)
Today, wastewater
infrastructure is often
subject to about one order
of magnitude more acid
s
e
corrosion than before
d
i
f
l
u
S
1980.
Corrosion Threshold
1980
1985
1990
0
1995
Data courtesy of the City of L.A., CA
Data provided by the City of Los Angeles
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
Sewer
When
the
dissolved
Other
bacteria
present
Bacteria in the
oxygen
concentration
inwastewater
the water
convert
falls
below
0.1
mg/l,
sulfates
to
sulfides.
consume
the
water
becomes
This
causes
the
rotten
oxygen.
septic.
egg smell, hydrogen
sulfide gas (H2S).
H2S Gas H2S Gas
Wastewater
pH ~ 7 O2
O2 Bacteria
D.O.<0.1 mg/l
O2
In water at pH 7,
about 50% of the
dissolved sulfide
converts to H2S gas.
1200
5.00
H2 S(g)
4.00
H2 S(aq)
HS -
1000
800
3.00
600
2.00
400
1.00
200
0.00
0
3
Skip
4
5
6
7
pH
8
9
10
H2 S (g) in air (ppm)
H2 S (aq) and HS - in solution (mg/L)
6.00
H2S
H2S
H2 S
H2S Gas
H2S Gas H2S Gas
SO42-
HS-
H2S
Thiobacillus
Andthe
This
virtually
acid
corrosion,
On
surfaces
above
nothing
not
“aging”,
isHbeing
then
the
water,
gas is
2S
done to stop
dissolves
the
it from
converted
to strong
happening.
infrastructure.
sulfuric
acid by
Thiobacillus bacteria.
Acid Attacks
Concrete
H2S + O2 = H2SO4
SO42-
HS-
H2S
Once
rebar is
exposed,
the
Collapses
routinely
occur
when
preventable
corrosion
sewer
is structurally
is allowed
to continue
compromised.
unchecked.
Acid Attacks
Concrete
H2S + O2 = H2SO4
SO42-
HS-
H2S
Corrosive surface conditions are can easily
be detected using a simple, inexpensive
surface pH test.
Unfortunately, it is rarely being done.
Rather, most cities implement expensive
CCTV, coring and capital intensive system
evaluations.
Take home message…
Surface pH
tells the whole story…
Red is bad, green is good.
7= Neutral
Above 7 = Basic
Below 7 = Acidic
Surface pH
(2” of sacrificial
concrete)
6
200 years
5
100
4
50
Corrosion Range
Years of
Life
7
20
3
2
1
0
0.001
0.01
0.1
0.25
Corrosion Rate (in./year)
1.0
Source L.A.County San District
Sewer design life is generally based on
100 years of useful service.
Surface pH ≥ 4; Life Cycle = 100 yrs
77
>200 years of corrosion life
66
44
100 years of useful life
Corrosion Range
pH
55
33
8 years
22
1
0
0.001
0.01 100 50 0.1
20 0.25
8
20
Years
ofRate
useful
life
Corrosion
(in./year)
0
1.0
Source L.A.County San District
1250%
When the surface
pH falls below four,
sewer life cycle costs increase
For example,exponentially…
the difference in annual cost
between surface pH 4 and 2 is…
Surface pH of two or lower is now
common.
But most cities (or consulting firms)
don’t measure for it.
Red is bad, green is good.
What color is your system?
Recall this slide
showing the
relationship between
wastewater
H2SpH and
H2S
S
hydrogen
sulfideH2gas?
H2S Gas
1200
H S
H2S
Gas H2S Gas HS
5.00
2 (g)
4.00
H2 S(aq)
-
1000
800
3.00
600
SO42-
HS-
2.00
H2S
400
1.00
200
0.00
0
3
4
5
6
7
pH
8
9
10
H2 S(g) in air (ppm)
H2 S (aq) and HS - in solution (mg/L)
6.00
2+ is
The amount
of gas
produced
by the
Mg(OH)
+ affected
2OH2 (S)  Mg
- causes a shift
wastewater
pH.
Higher
= less
gas.
OH
in the
solublepH
sulfide
equilibrium:
H2S  H+ + HS1200
5.00
H2 S(g)
4.00
H2 S(aq)
HS -
1000
800
3.00
600
2.00
400
1.00
200
0.00
0
3
4
5
6
7
Wastewater pH
8
9
10
H2 S(g) in air (ppm)
H2 S (aq) and HS - in solution (mg/L)
6.00
Hydrogen Sulfide Performance
Thioguard
X
X
X
H2S Gas
Mg(OH)2
addition
90
80
%H2S Gas Reduction
70
60
50
40
30
20
10
0
0
10
20
30
40
Gallons Thioguard/Million Gallons Treated
50
Thioguard
extends
useful life of the
Corrosion
whichthe X
X
life
system limits
whilesystem
controlling
odors and FOG
X
expectancy
Thioguard
Typical Reduction in Hydrogen Sulfide Gas
Corrosion Rate Vs. Wastewater pH
Corrosion Rate (mm/yr)
1.40
1.20
1.00
0.80
Without Thioguard
0.60
0.40 Corrosion
> 80% Less Corrosion
0.20
With Thioguard
0.00
4.5
5.5
6.5
7.5
pH
8.5
9.5
The Benefits of Thioguard Addition
System Wide Corrosion Control
System Wide Odor Control
System Wide FOG Control
Treatment Enhancement Effluent Quality and Plant Capacity SVI, TSS, MLSS, MLVSS, RAS, DOC
Biosolids Volume and Disposal
Safety and Compliance
BOD, COD,
In the greater Los Angeles area alone,
Thioguard is used to treat nearly 200 million
gallons per day
Approximately 150 direct
addition sites.
Thioguard has proven cost effective and
has now been accepted for wastewater
system treatment by over 60 cities across
the U.S.
Thioguard is safe for personnel, the
environment and the wastewater system.
Thioguard
® TST
www.THIOGUARD.com