Item 4BCITY OF
SOUTH LAKE
MEMORANDUM
(June 16, 2015)
To: Shana Yelverton, City Manager
From: Robert H. Price, P.E., Director of Public Works
Item 4B
Subject: Approve an annual agreement for providing odor control
treatment at lift stations with Premier Magnesia, LLC in the
amount of $138,000
Action
Requested: Approve an annual agreement for providing odor control treatment
at lift stations with Premier Magnesia, LLC in the amount of
$138,000.
Background
Information: Since the construction of the Shady Lane and Lonesome Dove
sanitary sewer lift stations in 2000, the city has had to treat the
wastewater to prevent hydrogen sulfide production in the sewer
system from affecting the residents of the Kirkwood Hollow
neighborhood. Premier Magnesia has been providing this service
for Southlake and Trinity River Authority since 2006 because
previous attempts to control the hydrogen sulfide with other
products were not successful. Under the proposed agreement, the
cost per gallon will increase 2%, from $2.68 to $2.73 per gallon.
Premier Magnesia is a sole source provider and patent holder of
this technology.
An additional benefit to this technology is the prevention of grease
buildup in the lift stations eliminating the need for City crews to
remove and dispose of excess grease.
Staff is recommending that Council accept the proposal offered by
Premier Magnesia, LLC to guarantee a rate $2.73 per gallon for
their services for a 12-month period with an estimated annual cost
of approximately $138,000.
Financial
Considerations: Funding for this program is provided in the 2015 and 2016
operating budget of the Waste Water Division.
Strategic Link: The annual purchase agreement for the magnesia treatment of
wastewater links to the city's strategy map relative to the strategic
focus area of Performance Management and Service Delivery. The
specific corporate objectives that are met by this agreement
include: Providing high quality customer service by eliminating
odors released in the collection system and optimizing the use of
technology with state of the art treatment of wastewater.
Citizen Input/
Board Review: N/A
Legal Review: None
Alternatives: The City Council may approve or deny the agreement to provide
odor control treatment at lift stations.
Supporting
Documents: Annual Contract Pricing Renewal Letter
Patent Documentation
Staff
Recommendation: Approve an annual agreement for providing odor control treatment
at lift stations with Premier Magnesia, LLC in the amount of
$138,000.
Staff Contact: Robert H. Price, P.E., Public Works Director
Chuck Kendrick, Deputy Director of Public Works - Operations
Q Q DOD Q Q DOD Q
MAGNESIA, LLC
May 20, 2015
Chuck Kendrick
Public Works Operations Manager
City of Southlake
Phone (817) 748-8080
Fax (817) 748-8103
ckendrick@ci.southlake.tx.us
Subject: 2015-2016 Thioguard — Magnesium Hydroxide Pricing
Chuck:
Pursuant to your request for a renewal of the annual contract for Thioguard, I am submitting this letter
to update you on the terms of the agreement. You may submit Purchase Orders either on a per load
basis, or a Blanket PO may be issued for the duration of the price in effect.
The price per gallon for the upcoming year will be $2.73 effective July 1st through and ending June 30tn
2016.
At the current combined rate of usage for Lonesome Dove and Shady Lane of 125 gallons per day, plus
or minus 10% for seasonal variability, estimated annual costs are between $124,556 and $137,012.
Premier Magnesia very much appreciates your cooperation and looks forward to a continued long-
term relationship as a quality supplier.
Sincerely,
y �Z_-
a
Mary P. Evans
South Central Regional Account Manager
Premier Magnesia, LLC
Thioguard TST
Phone: 903.245.6316
20108 CR 186
Flint, Texas 75762
Email: mevans@premiermagnesia.com
Q Q DOD Q Q DOD C�
MAGNESIA, LLC
May 20, 2015
Subject: 2015-2016 Thioguard — Magnesium Hydroxide Pricing
Accepted:
Laura Hill, Mayor
Date
Attest:
Lori Payne, TRMC
City Secretary
Date
2
.mil �!�'11111Fl�
� s ���
CHEM/GALS, LLC
June 1, 2010 300 West Barr Harbor
Suite 250
West Conshohocken, PA 19406
Tel: (610) 828-6929
Mr. Chuck Kendrick Fax: (610)
Deputy Director of Public Works - Operations
Department of Public Works — City of Southlake
1905 E. Continental Blvd.
Southlake, TX 76092
Re: Premier Chemicals, LLC s THIO UARD Magnesium Hydro ide Slurry Proposal to City
of Southlake
Dear Mr. Kendrick,
I have been asked to provide you a brief description of the claim coverage for U.S. Patent No
5,833,864, entitled METHOD FOR THE REDUCTION AND CONTROL OF THE RELEASE OF GAS
AND ODORS FROM SEWAGE AND WASTE WATER, (the "'864 Patent").
The patent relates to using magnesium oxide or hydroxide to control odor in municipal
sewerage or wastewater.
The '864 Patent includes 26 claims directed towards controlling odor in sewers by adding
magnesium hydroxide or magnesium oxide. For example, claim 1 broadly claims controlling odor in
municipal sewerage or wastewater that includes at least one compound which can be reduced to form
hydrogen sulfide. Odor is controlled by simply adding an effective amount of magnesium hydroxide or
magnesium oxide to the municipal sewerage or wastewater.
I have included a copy of the patent with this letter.
Premier has spent a great deal of effort, research, time, trial and error, as well as significant
funds, in order to obtain the patent rights described above and to develop a product of the quality that
our customers require. We believe the efforts expended to obtain such patent is indicative of the effort
our Company will put forward to insure the City of Southlake will receive a competitive, efficient and
high quality product that will produce superior results.
I hope that this helps in your understanding of Premier's patent position, however, if you wish
to discuss the enclosed or have any questions please do not hesitate to contact me.
Very truly yours,
Stephen A. Becker
Vice President, General Counsel
and Secretary
cc: P. AN
M. Madolora
T. Miller
THIOGUARD PATENT LTR.
United States Patent (191
Miller et A
[54] mu, MOD FOR THE REDUCTION AND
CONTROL OF THE RELEASE OF GAS AND
ODORS FROM SEWAGE AND WASTE
WATER
(75] inventors: Thomas M. Miller, Walnut, Calif.;
Mark A• Shand, Findlay, Ohio
[73] Assignee: PSC Technologies, Inc._ King of
Prussia. Pn.
[ m ] Notice: This patent issued an a continued pros-
ecution application filed under 37 CFR
1,53(d), and is subject to the twenty year
patent term provisions of 35 U,S,C.
154(a)(2)•
[21] Appl No..: 690,502
[22] Filed: Jul. 8, 1996
Re4nted U.S. Application Data
(63] Coutionation of Ser No. 386,735, Feb. 10,1995, nbandnned
[51] Inc C16 .- »...-» ••,...». CO2F 1/66, CO2F 11/00
[52] U.S. Cl..,.M..-..m.,•.T.• . 2101724; 210r749; 210/9 3;
[58] Field of Search ....,_._...-..._._ .M, .., 210R24. 749.
2101916.903
[56] References Cited
U,S, PATENT DOCUMENTS
2,852,584
911958 Kline .
....... ._. 2101916
3,080,253
311963 Dietz et al,. .
3,3T1,271
4/1968 Caen
210/45
3,697,322
10/1972 Lea et ol.~
3,705,098
1211972 Shegbetd et al M» .M.••.•.,,•••-•
210163
3,862A51
111975 Sprits ct al. .
3,974,783
811976 Flynn .- ,»,., ».......••...•..
• 11019
4.118,3I9
1011979 Miynnob= ct al, .•, ...............
2ID51
4,125,466
11/1978 N iyanoh= et al ..•..
, ....•,.-.• 210167
4,169,906
1011979 I1allstrOm et al. ,
4,456,05
6/1984 Albmesa et al• -
4,615,918
10/1986 Reicbert et al. -
4,668,541
511997 Fagedund .
4,67%315
611997 Memr3er et. ol, .
l
- g1gHi'
STORAGE TANK OR DRUM
IN 1111 VI IN 11 H 11111111111 IN UP 1111111
[l1] Patent Number; 5,833,864
[45] Date of Patent: *Nov. 10, 1998
4,675,114 6/1987 Zagrai et al ,.••.,.. , •- •.--•.•• 2101666
4,710,404 1211997 Reichert et al
4,786,525 1111998 Kayser et al. .
5,220,995 711993 Storer .... .-- 210191.7
5,246,641 9/1993 Perrin et al.
5,422,015 6/1995 Angell zion51
FOREIGN PATENT DOCUMENTS
1326682 4/1963 France .
424919 311935 United Kingdom -
2123516 211984 United LGngdom
()TM PUBLICATIONS
Excerpts from ASCE Manuals and Reports on Engineering
Practice —No. 69 titled "Sulfide in Wastewater Collection
and Treatment Systems".
Davis Process Division of Dais Water & Waste industries,
Inc.; Process Division Techtucal Bulletin No. B-401. Bimx-
ide ... the natural solution., APreprietary Product Designed
to Promate Nammlly Occwming Process Within Wastewater
Collection and Treattneat Systems Which Elltuinnte Order
Producing Compounds.
Sewer Corrosion Control and Rehabilitation, County Sani-
tation Districts of Los Angeles County, 5 Pages.
Caustic Spray For Sewer Crown Corrosion Control, by
Jamie Balda. 11 Pages.
Microbial Energy Generation/Oxidation of Inorganic Sub-
strates. pp. 158--159.
Preparing Collection Systems for Water Conservation, pp-
52 -57. Water Environment & Terlenology, Aug, 1993,
(List continued on mart page.)
primary Ewrniner—Nail McCarthy
Anome)l Agin; or Firm—Ostrolenk. Faber, Gerb & Soffeh,
LLP
[57] ABSTRACT
A method for reducing and controlling the formation and
release of add gases and odors associated therewith. par-
ticularly from hydrogen sulfide, in sewerage or waste water,
wherein magnesium hydroxide and/or magnesium oxide are
added to the sewerage or waste water.
26 Claims, 3 Drawing Sheets
2 4\
3
pH = 6 8, H25=0-3 porn pH =9.1, H25 - 0,07ppm
DIRECTION OF FL.OW
5,833,864
Pale 2
917HER PUBLICATIONS
Metals Meetlheir Match pp. 69 73, Water Environment &
Technology, Sep, 1993.
Product Reportl5urfactants for household detergents—pat-
rochernical raw materials and uses, pp. 40-41 & 46, MEN,
inn. ?A,. 1994,
Generation and Control Sulfide in Filled Pipes. by Dr.
Richard D. Pomeroy, Pomeroy and Associares. Pasadena,
Calif.. Frmn Sewage and industrial Wastes. col. 31. No. 9.
1959,
Process Design Manual for Sulfide Control in Sanitary
Sewerage Systems. U.S. Environmental Protection Agency
Technology Transfer. Oct. 1974. 9 Pages.
U.S. Patent Nov. 10, 1998 . Sheet 1 of 3
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5,833;864
METHOD FOR THE REDUCTION AND It is also an object of the present invention io provide a
CONTROL OF TKE RELEASE OF GAS AND method of maintaining a level of hydrogen sulfide which is
ODORS FROM SEWAGE AND WASTE below an acceptable level.
WATER It is a further object of the invention to provide methods
CROSS-REP13RENCE TO RELATED 5 of reducing or eliminating odor associated with Waste water
APPLICATIONS or sewerage,
This application is a continuing application of U.S. Sec, It is also an object of the present invention to provide a
No. 0888035 filed Feb 10. 1995 now abandoned method to minimize the formation and release of both
hydrogen sulfide and ammonia in waste water or sewerage.
BACKGROUND OF TAP. INVEbrIION
1, Feld of the Invention
The present invention relates to the control of gaseous
release and of odors associated with sewerage and waste
water and more particularly, to the reduction and control of
the release of acid gases, such as hydrogen sulfide. from
sewerage or waste water,
2. Description of the Related. Art
Sewerage and waste water gearrally contain sulfates and
other contaminants which, upon reduction. become (directly
or indirectly) gaseous compounds which are released gen-
erating unpleasant odors. For example. sulfates are reduced
to sulfides associated with the release of hydrogen sulfide
gas. The reduction of sulfates can proceed by the action of
sulfate -reducing bacteria including Derulfovibro sulfricans,
Hydrogen sulfide and other acid gases which are released
include potentially dangerous contaminants and lead to
unpleasant odors.
Several methods have been proposed and used to control
the release of hydrogen sulfide, These include methods
which reduce the growth of the anaerobic bacteria or which
chemically bind sulfides. However, these methods have
drawbacks. such as high costs, implementation difficulties
and safety concerns.
In particular ferrous and ferde chloride (iron) and liquid
caustic soda (sodium hydroxide- pH 13-1¢) are currently
added to sewers to control sulfide generation and catrosion.
The iran is added continuously to bind the sulfide as a
nonsoluble iron sulfide precipitate.
Caustic Coda is gcaerally added semi -weakly to provide a
thirty minute, high pH, shock dose to the anaerobic bacteria_
The addition of caustic soda acts by neutralizing the sulfuric
acid which has already been formed by the bacteria, inac-
tivating and destroying the bacteria. and limiting the forma-
tion of new colonies of bacteria.
The use of caustic soda has been found to have several
drawbacks, Fast, caustic soda only has a bsnporary effect on
the bacteria. Second, caustic soda is hazardous and is highly
toxic to humans. Sven a small amount of caustic soda can
cause permarent blindness.
It is expected that in the future the generation of hydrogen
sulfide (H2S) will increase, particularly as more municipali-
ties adopt water conservation programs that include the
installation of low -flow plumbing devices. As a result of the
reduced flows in such systems, water may be retained longer
in the pipes, wet wells and force mains of the colleciion
system; damming caused by settled solids and grease may
increase; and less dissolved oxygen (DO) may be present
due to increased biochemical oxygen demand (BOD).
Absent the teachings of the present invention. all of these
changes might otherwise exacerbate the problems addressed
by the invention.
SUMMARY OF THE INVENTION
it is therefore an object of the present invention to provide
methods which are safe and effective for controlling the
formation and release of acid gases. particularly hydrogen
sulfide.
10 It has been found that the formation and release of acid
gases, particularly hydrogen sulfide, which are associated
with the unpleasant odor of sewerage and waste water can be
controlled or eliminated by introducing magnesium hydrox-
15 ide andlar magnesium oxide into the contaminated watCL
Moreover. It has surprisingly been shown that magnesium
hydroxide is able to maintain a pH level which minimizes
the levels of both hydrogen sulfide and ammonia. Further,
the levels of hydrogen sulfide and the pH of the contami
20 aaLad water can be maintained at an acceptable level for a
significant period of time.
Other features and advantages of the present invention
will become apparent from the following description of the
invention which refers to the accompanying drawings.
25 BRIEF DESCRIPTION OF THE DRAWINGS
For the purpose of illustrating the invention, there is
shown in the drawings an embodiment which is presently
preferred; it being understood, however. that the invention is
30 not limited by the precise arrangements and instrumentali-
ties shown.
FIG, 1 is graph of the relative concentrations of hydrogen
sulfide and ionized hydrogen sulfide at various pH levels;
F103 2 is a graph of the pH level and aqueous sulfide level
35 after the addition of magnesium hydroxide; and
FIG. 3 is a diagram of a representative configuration for
the addition of magnesium hydroxide and/or oxide to waste
water or sewerage,
40 DETAILED DES(RIMON OF THE
INV=ON
It has been found that the addition of an agent including
magnesium hydroxide (ivMg(OH)2), and/or magnesium oxide
as (MgO) to sewerage or waste water which is contaminated
with compounds which can be reduced to acid gases,
reduces or eliminates the release of these gases and the odor
associated therewith.
The addition such an agent to sewerage or waste water is
50 able to alter the pH of the solution into a preferred range of
approximately 7.5 to 9,5, and to maintain pH in that pre-
ferred range for extended periods, The amount of the agent
needed to achieve the preferred pH varies with the amount
of water to be treated. Monitoring pH of the treated water
$5 during addition of the agent is recommended so that the
operator may increase or decrease the amount of agent as
necessary.,
In general. the fraction of hydrogen sulfide relative to
ionized hydrogen sulfide which is present in solution is
6a dependent on the pH of the solution. It is desirable to reduce
the level of hydrogen sulfide which is not ionized so as to
reduce the unpleasant and harmful odors associated there-
with. As discussed in more detail below, applicants have
discovered that a pH of 7.5- 4,5 (especially &0-9.0) is
65 particularly preferred both for reducing release of acid gas
and also for maintaining better levels of other compounds as
well,
5,833.864
As shown in FIG. 1. which compares the ratio of hydro--
tolerance of common acid producing bacteria, It is noted that
amounts of lime (calcium hydroxide) can be added to
gen sulfide to ionized hydrogen sulfide, at a constant
temperature, the percentage of ionized hydrogen sulfide
small
magnesium hydroxide and/or magnesium oxide slurry to
increases with an increase in pH, The largest effect is seen
in the pH range of 6.0 to 8,0. In particular, at a pH of 6.0. 5
increase the pH and enhance the sIttrry's ability to kill
bacteria. It is anticipated that other biocides or hardening
90.1% is hydrogen sulfide. while at a pH of 8.0. only 8.3%
agents such as sodium silicate. sodium bi-sulfate, magne-
magnesium chloride, phosphates, or other
is hydrogen sulfide. Further, at a pH of 8,5. 3% is hydrogen
sulfide and at a pH of 9.0. the hydrogen sulfide level drops
sium sulfate,
materials intended to $apart mechanical strength, may be
to less than M,
added to further enhance its performance.
Therefore. due to the relative insolubility of the agent of 10
in
Secondly, as the bacteria is re-cstablished, the alkalinity
by the magnesium hydroxide and/or magnesium
the invention, conditions can be maintained over time
which the amount of hydrogen sulfide which is present or
provided
oxide neutralizes the acids produced by the bacteria and
is reduced and therefore. the odors associated with
prevents the rapid re-establishment of bacteria -
released
the release or presence of hydrogen sulfide are minimized or
A magnesium hydroxide and/or` magnesium oxide slurry
eliminated. In some embodiments, hydrogen sulfide levels 15
can be prepared by adding, caustic calcined magnesium
arc desirably reduced to six parts per million or less
the
oxide (MgO).preferably in a dry powder four. to water,The
magnesia can be obtained from any of the known suppliers
Further, it has surprisingly been found that, at pre-
ferred pH's of the invention, the undesirable release of
iacluding Premier Services Corporation. King of Prussia,
ammonia is also minimized. In contrast to hydrogen sulfide
of 20
Pa. Premier Services sells magnesia in dry powder form
under the trademark MAGM&
levels. which decrease. as the pH increases, the release
ammonia gas increases with an increase in pH_ Therefore, a
When magnesium oxide is added to water it undergoes
to magnesium hydrox-ide. The
balance is preferred in which the pH level is both (1) high
enough to seduce the formation and releast of hydrogen
hydration and is converted
rate of this reaction can be varied depending upon the
sulfide and (2) row enough to prevent the formation and
surface area of the MgO, starting water tempemtitre, vessel
of ammonia. It has been found that the optimal 25
configuration. and agi�p Either a slowly h
release
baLmce can be achieved by maintaining a pH in the range of
or a fully by g( H)z slurry added to the
approximately 7.5 to 9.5. especially 8.0 to 9.0- and most
by maintaining a pH of approximately 8.3.
contaminated water.
A magnesium hydroxide slurry can also be purchased
preferably.
Moreover, a pH level substantially above 9.0 can be
harmful to bacteria which are beneficial to treatment of 3o
form any of the known suppliers. including Premier Services
which sells a magnesium hydroxide slurry under the trade -
waste water and sewerage. Io comparison to other pH
mark AQUAMAC4.
increasing compounds, magnesium hydroxide has been
pHin the desired range
In a preferred embodiment of the invention. a spetially
hydrated and formulated slurry, marketed by Premier Ser-
found to slowly reach and maintain a
wilhout substantially overshooting the maximum level, As
vices Corporation under the trademarkTHIOGUARDTm. is
such; there is less osmotic shock and the helpful organisms 35
added to sewerage or waste water, Without intending to be
arc not'destroyed
broad by theory. It is believed that this slurry offers a safe.
Thcrafine, magnesium hydroxide and/or oxide have been
economic alternative reagent for acid neutralization and
treatment and has been found to be particularly
found to be particularly suitable for the prevention of odor
in sewerage and waste water since the alkalinity and 40
water
effective in controlling odors later alia by achieving the pH
release
properties of magnesium hydroxide are such that it is easy
and other effects discussed herein, it is believed to neutralize
wwnful sulfuric acid It is an off-white slurry composed
for the operator to keep PH levels within the preferred range
discussed above, without inadvertently raising pH so for
predominately of agglomerated magnesium hydroxide par -
above the preferred range that the undesirable effects dis-
titles and is made from hydrated calcined natural magnesite
from sea water. bitterns, or brines. Table 1
cussed above become problematic 45 or precipitated
Moreover, it has been found that the low solubility of the below, sets forth a representative cbemical analysis of it on
magnesium leads to a time released alkalinity so that the pH
a loss free basis.
level is more stable and is maintained upstream for a longer
TABLE I
period of time, As shown in FIG. 2. magnesium hydroxide
was able to maintain a pH of above 75 and a level of 5o viscosity, wutipoise Boa-6000, typK-BUY 5000
aqueous sulfides at or below 5 ppm for thirty days.
In addition to the benefits of magnesium bydroxide and/or
% Solids 55--65 , _,
Specific Sattaee Area Typically tom g
Chemical AaatyBis BsuL), wt �o
oxide discussed above, the use of magnesium hydroxide
and/or oxide is preferable for a number of reasons First it
MRo 90-99
is noted that magnesiumhydroxide requires no placarding or 55
Coo 03-4 n
n �D
special handling and presents no chemical hazard to the
b
SiR,o 0.t-2.0
eaviroument, users, or the public. Second, magnesium
'
hydroxide has a higher neutralizing capacity per mole than
soda due to its two OH ions. Third. the by-products
The component R.203 refers to natural impunities Such as
caustic
produced by the reaction of magnesium with hydrogen 6o A1203 and Fe.03 which are indigenous to ore bodies Other
in to) SiO2, e.g. M9CO3
sulfide tend not to be hazardous as with some by products of
Finally, the magnesium require-
insolubles besides (err addition
and/or CaCO3 may be included, The product THIQ-
hydrogen sulf€dereactions.
ments are less dependent on sulfide eonceutxation-
is believed that two mechanisms are respoasihIe for the
GUARD'S is made from natural ore and there are some
natnrnl variations in the percentages of various ingredients
it
r$ec&bness of magnesium hydroxide and/or magnesium 65 as shown inter alia in 'liable L
In a preferred embodiment. as shown in FIG. 3, the
oxide, First. magnesium hydroxide has a pH of apprnxi-
is the
magnesium hydroxide or magnesium oxide in the form of a
mately i0.5, which. while safe to humans. above
5,933.864
5
slurry is topically applied to a stream of sewerage or waste
water. In particular, a storage tank or drum I which holds
magnesium hydroxide and/or magnesium oxide pumps the
magnesium through a maintenance hole 2 to a sewerage flow
3. Odors from downstream maintenance holes d and carco-
sion on crowns and maintenance holes 5 are reduced or
eliminated.
Addition of sufficient THiOGUARDTm to the sewerage to
raise the pit to 9.0-9.5., which takes somewhere between
8.5-100 mg/L dependent upon type of sewerage is sufficient
to reduce odor and corrosion problems in sanitary sewers.
This occurs because at this pH dissolved hydrogen sulphide
gas is at a minimum and does not tend to escape into gaseous
phase and contribute to odor and corrosion. For instance
addition of IMOGUARDTAI to sewerage at approximately
100 nigh results in an almost instantaneous drop of aqueous
sulphides from an initial 16 ppm to less than 1,0 ppm for a
period of 4 days and a subsequent rise to between 6-6.5 for
a period of 50 days,
Apart from its ability to alter sewerage pH to reduce
dissolved hydrogen sulphide gas, there is a surface reaction
berweenTfROGUARDTm and dissolved hydrogen sulphide.
which results in adsorption of the gas onto the solids phase.
Mg(03)p+HrS„ L,-Mg(OH)1(HtS),iMg(HS},+20s-+MRSOA
Further reaction results in the formation of magnesium
hydrosulphide, which can be oxidized by dissolved oxygen
to form soluble magnesium sulphate which does not sub-
stantially, contribute to odor or corrosion.
Due to its limited solubility in water, it is very slow to
release hydroxyl ion (OH—) in normalpH range of sewerage
compared to other alkalis such as lime and caustic soda,
M6(OH)a-4Mg�-+201r-
6
sulated in sodium silicate, In some embodiments, this dry
farm may constitute the agent added to sewerage or waste
water in accordance with the invention. Ilse acid produced
by surface bacteria is neutralized by the sodium silicate, in
5 addition, as the sodium silicate dissolves, the magnesium
oxide is exposed, thereby dehydrating the bacteria and
neutralizing the hydrogen sulfide,
Although the present invention has been described in
relation to particular embodiments thereof, many other
10 variations and modifications and other uses will become
apparent to those skilled in the art- It is preferred, therefore,
that the present invention he limited not by the specific
disclosure herein. but only by the appended claims.
we claim
1. A method for reducing the formation and release of
15 hydrogen sulfide in municipal sewerage or waste water,
comprising the step of..
adding an effective amount of an agent that includes a
compound selected from the group consisting of mag-
nesium hydroxide and magnesium oxide to said
20 municipal sewerage or waste water, wherein said
municipal sewerage or waste water includes at lease
one compound which can be reduced to form hydrogen
sulfide.
2. The method. as recited in claim 1, wherein said agent
25 is a slurry further including sodium silicate.
1 The method, as recited in claim 1. wherein said agent
is a hard alkaline material composite of unhydrated magno-
sium oxide encapsulated in sodium silicate.
4, The method, as recited in claim 1,, wherein the com-
30 position is a slurry including:
35
Consequently. MIOGUARDT"t is able to continue to raise
the pH downstream of the original point of addition without
resulting in excessively high loml pH's. For instance, add-
ing it at a rate of 100 mg(l to sewerage is capable of
sustaining a pH greater than 84 for 24 hours. 40
Its use to control odor/corrosion problems in sewerage is
not limited to just hydrogen sulphide but could encompass
other acidic gases/vapors such as sulphur dioxide and sul-
phur compounds which contain an ionizable hydrogen ion.
such as mereaptans containing the --SH group. 45
It should be realized by those skilled in the art that the
magnesium hydroxide and/or magnesium oxide can be
added to any other water or liquid solution that is contami-
nated by compounds which can be reduced to acid gases.
particularly sulfates and mercaptans, 50
The characteristics of the magnesium hydroxide and/or
magnesium oxide slurry can be varied to provide the opti-
mum pumping eharadetisties and to treat different levels of
contamination
The properties of the slurry can be varied by any of the 55
known methods including changes in the solids to water
ratio, or by the use of polymers to enhance or alter these
properties as desired for differing field conditions or equip-
ment configurations, a g... increasing or decreasing the water
content or by adding in more magnesia powder, 60
It is recommended that the slurry should include at least
30%, preferably at .least 50%. by weight magnesium com-
pound in the form of magnesium oxide, magnesium hydrox-
ide or a rnil[rure thereof.
Magnesium oxide can also be mixed with sodium silicate 65
to produce a slurry which, when dried, yields a hard alkaline
material composite of unhydrated magnesium oxide encap-
Chmakal Analysis (kiss tree basis)
a1 %
M80
about 92-9B%
CIO
about 5-3.5%
R201
about 5-1.5%
mwlables
about 5-10%
Viscosity, cPs
about SOD-1D,000
density, nwo
about 11.E-11, 8
r% soU& by wt %
abota 45-55
5. The method. as recited In claim 1, wherein said agent
Is substantially continuously, added to said sewerage or
waste water.
6. A method of controlling hydrogen sulfide odor associ-
ated with municipal sewerage or waste water, comprising
the step of:
adding an effective amount of an agent that includes a
compound selected from the group consisting of mag-
nesium hydroxide and magnesium oxide to said
municipal sewerage or waste water, wherein said
municipal sewerage or waste water includes at least one
compound which can be reduced to form hydrogen
sulfide.
7. A method of obtaining a minimal level of hydrogen
sulfide and of ammonia in municipal waste water or
sewerage, comprising the step of:
adding an effective amount of an agent that includes a
compound selected from the group consisting of mag-
nesium hydroxide and magnesium oxide to said
municipal sewerage or waste water, wherein said
municipal sewerage or waste water includes at least one
compound which can be reduced to form hydrogen
sulfide.
S., The method of claim 1. wherein said agent is added in
an amount effective to reduce hydrogen sulfide levels to no
more than 6 parts per million.
5.833.864
9, The method of claim 6. wherein said agent is added in
an amount effective to reduce hydrogen sulfide levels to no
more than 6 parts per trillion.
10, The method of claim 7, wherein said agent is added in
an amount effective to reduce hydrogen sulfide levels to no
more than 6 parts per million.
11, The method of claim 1. wherein said agent is added in
an amount effective to maintain pH of said sewerage or
waste water between 7.5 and 9.5,
12. The method of claim 6, wherein said agent is added in
an amount effective to maintain pH of said sewerage or
waste water between about 7,5 and 9.5,
13, The method of claim 7. wherein said agent is added in
ao amount effective to maintain pH of said sewerage or
waste water between about T5 and 9,5.
14, The method of claim 1, wherein said agent is added in
an amount effective to maintain pH of said sewerage or
waste water between about 8,0 and 9.0,
M The method of claim 6, wherein said agent is added in
an amount effective to maintain pH of said sewerage or
waste water between about 8,0 and 9.0,
16, The method of claim 7, wherein said agent is added in
an amount effective to maintain pH of said sewerage or
waste water between about 8.0 and 9.0,
17. The method of claim 1, wherein said agent is added in
an amount effective to maintain pH of about 8,3.
18, The method of claim 6, wherein said agent is added in
an amount effective to maintain pH of about 8,3,,
19. The method of claim 7, wherein said agent is added in
an amount effective to maintain pH of about 83.
5 20. The method of claim 1, wherein lime is also added.
21, The method of claim 6, wherein lime is also added.
22, The method of claim 7, wherein time is also added.
23, The method of claim 1, wherein said agent is a slurry
comprising 30-50% by weight of said magnesium.
24, The method of claim 6, wherein said agent is a slurry
10 comprising 30-50% by weight of said magnesium.
25. The method of claim 7, wherein said agent is a slurry
comprising 30-50% by weight of said magnesium.
26, The .method, as recited in claim 1, wherein the
composition is a slurry including: Physical and Chemical
r5 Properties of THIOGUARDTH Chemical Analysis (Dry
Basis), wt %
M80
About90-99
C20
About 0,3-4,0
Sip,
tabout0.34.0
R30a
obool0.I-U
Mucosity
Boll-600a sat; !=,
96 Solids
about 55-65,