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Hydrogen sulfide (H2S) has been the source of
countless odor complaints directed to those responsible for
operating municipal and industrial wastewater facilities --
probably the source for more complaints than any other
malodorous compound. In addition to the rotten egg odor, H2S
poses serious corrosion problems costing many millions of
dollars each year, serious health and safety concerns, and can
diminish the effectiveness of any wastewater facility.
The biological transformations involved in the sulfur cycle
are tremendously complex, but it is generally accurate to say
that sulfate-reducing bacteria are the principal causal agents
-- reducing sulfate to sulfide. The biological production of H2S requires anaerobic conditions (conditions deficient in
dissolved oxygen [DO]), but the problem often occurs where
design intends largely aerobic conditions. For example, sludge
blankets in clarifiers are frequent culprits; stabilization
ponds often stratify with heavy loadings, creating anaerobic,
facultative and aerobic layers. (See Figure 1.)
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Figure
1. H2S production in clarifier sludge blanket and
anaerobic stratum of pond.
All of the following have been used to combat H2S.
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| Aeration |
Turbulence
prevents settling, releases H2S |
| Chlorination |
Hazardous |
| Containment
and Scrubbing |
High
capital and operating costs |
| Hydrogen
Peroxide |
Expensive
(not reaction-specific with sulfide) |
| Iron
Salts |
Rarely
fully effective |
| pH
Shocking |
Kills
or inhibits treatment |
| Potassium
Permanganate |
Expensive |
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There is no magic involved with the biological creation of H2S.
Neither is there any magic involved with its biological removal.
PERSNICKETY® 713 is a carefully developed, precisely
balanced blend of proprietary, naturally occurring, strict and
facultative anaerobic bacteria in a liquid medium. They are
selected and cultured for their ability to reduce H2S
to elemental sulfur, which is stored intercellularly. The
function is as follows:H2S
+ PERSNICKETY® 713 ---> S + new
PERSNICKETY® bacteria.
All
members are non-toxic, non-pathogenic, harmless to aquatic life
and compatible with other desirable bacteria found in
wastewater. They become a synergistic part of the biomass, and
simply do what nature intended them to do.
Much of our marketing focus is on ponds and lagoons because odor complaints commonly create the greatest sense of urgency for many of our clients, but potential benefits are much broader. You can reduce cost of and improve plant operations and effluent with Persnickety® 713.
Here's an important example: 713 can reduce electrical cost. Since some members of 713 are facultative and can use combined oxygen, they can tap into a huge, unused resource. Other members are photosynthetic and will use CO2 and produce oxygen when functioning in sunlight. While photosynthetic bacteria are uncommon, they do exist and should not be confused with algae. In fact, in most facilities algae commonly seen in clarifiers will be out-competed and slowly leave the system. Aeration in activated sludge basins can sometimes be markedly reduced and sufficient DO still retained. We have observed up to a seventy-five percent reduction in aeration employed.
Pre-Treatment, Collections/Lift Stations: H2S and grease control, reduced septicity, collections start to become part of the treatment system, improved safety.
Primary Treatment: H2S and grease control, improved settling, improved BOD and solids removal, higher DO.
Secondary Treatment: H2S and grease control, improved BOD and solids removal, improved flocculation, higher DO, aeration electrical savings, ponding and fly control in filters, better settling and improved clarity in final clarifiers.
Solids Handling: H2S control, less solids, better settling, improved supernatant.
The benefits and limitations described below apply to ponds, lagoons, and mechanical plants.
- Complaints due to H2S odors cease or
are greatly diminished. As importantly, corrosion damage and the
health and safety dangers posed by H2S are
correspondingly reduced. Cost of treatment is very competitive.
- Even low levels of highly toxic H2S can adversely
affect the health of a biomass, greatly reducing its activity
and efficiency. The impact of H2S varies in specific effect
from location to location, but a detoxified, rejuvenated biomass
will perform more efficiently. Thus, potential exists for
improving biochemical oxygen demand (BOD) and solids removals
and for decreasing accumulations of organic solids.
PERSNICKETY®
713 will also help to control animal and vegetable fats, oils
and greases (FOG). These compounds are exceptionally stable and
require extended time for breakdown. Certain members of 713
speed the process, creating intermediates (proteins, fatty
acids, glycerols). These simpler compounds are converted far
more readily by normally present bacteria. This benefit will
usually be seen in domestic plants with normal domestic FOG
loadings.
PERSNICKETY® 713 is
appropriate in all circumstances. It is formulated to function
in open tanks, ponds, lagoons, ditches and the like, where
anaerobic conditions allow sulfate reducing bacteria to flourish
and produce H2S. It is not normally recommended for
severely anaerobic conditions such as those found in anaerobic
digesters and highly septic collection lines. Here are a few
simple checks to determine appropriateness:
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A biological process takes time. 713 populations must build to
equal the problem. PERSNICKETY® 713 is not an
instant answer, but once established (approximately 10 days), it
serves remarkably well.
The application of PERSNICKETY® 713 is
straightforward -- batch dose 2 times per day, either manually
or by metered pump, at a point which provides maximum
dispersion. All members of 713 will metabolize and reproduce.
However, it is important to recognize that the normally present
bacteria have an ecological advantage over those introduced.
PERSNICKETY® 713 can never dominate a system.
Without repeated inoculations, the 713 populations will be
overwhelmed and will eventually disappear.
Table
1 details required rates of inoculation. The task is to build
and maintain populations of PERSNICKETY® 713 in
sufficient numbers to keep up with the amount of H2S
produced. Potential for H2S production is governed by
favorable conditions for its production and the amount of food
available for conversion. The figures on the next page are good
starting guidelines. Once H2S is firmly controlled,
it may be possible to reduce inoculation levels slowly and
incrementally to determine minimum amounts.
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For
the first 10 days of inoculation, triple the recommended
rates.
If
a system is killed by toxic shock, start over.
If
organically shocked, triple rates until recovery is
complete.
If
H2S control is only partial or sporadic, increase
incrementally until control is firm.
If
wastes are known to be rich in sulfur compounds, double
recommended rates.
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| BOD
STRENGTH IN MG/L |
*
713 PPM : FLOW/VOLUME |
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<100 |
1 |
2 |
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100-299 |
2 |
2 |
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300-499 |
4 |
3 |
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500-699 |
6 |
4 |
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700-999 |
8 |
5 |
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1-2000 |
10 |
6 |
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2-3000 |
20 |
7 |
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3-4000 |
30 |
8 |
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4-5000 |
40 |
9 |
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5-6000 |
50 |
10 |
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6-7000 |
60 |
11 |
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7-8000 |
70 |
12 |
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8-9000 |
80 |
13 |
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9-10000 |
90 |
14 |
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>
10,000 - consult your sales representative. |
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When treating problematic ponds or lagoons
receiving no flow, read Volume column only.
For those receiving Flow, add both Flow and
Volume columns and use this level until H2S
has been reduced to desired level. Then treat
using Flow column only. |
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Your nose will tell you of your success, but it will not
quantify reductions in H2S. Quantification can be
accomplished using Standard Methods testing. Both the iodometric
and methylene blue methods can suffer from interfering
substances. It is vital to pretreat samples (Standard Methods
427 B. "Sample Pretreatment to Remove Interfering
Substances or to Concentrate the Sulfide") for accurate
results. Another, and very simple way to measure dissolved
sulfide is to use sulfide ion analyzer tubes. They will provide
a reading in less than two minutes, and are very useful field
tools. They will not provide the precise accuracy of Standard
Methods testing.The
importance of measuring reductions is two-fold. Firstly,
reductions can be demonstrated to those concerned. As
importantly, the measurements will allow you to optimize
inoculation rates - i.e. if readings begin to creep up,
increase; if control is steady and firm a decrease may be
possible.
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| General
Description - Strict and facultative
anaerobes in a liquid medium. Gram-negative.
Cell shape varies from spherical to rod shaped
to vibrio and spiral shaped. Individual cell
size from .3 microns to over 6 microns. Color
of cell suspensions from purple-violet,
purple, red, orange-brown to brown.
Multiplication normally achieved through
binary fission although some members have a
polar type cell growth and multiply by
budding. |
| Key
Characteristics - Motile via polar
flagella. Some members exhibit excellent
growth at low (4°C) temperatures. Growth over
6.0 - 9.0 pH. Growth possible using sulfide as
sole electron donor. Will utilize molecular
hydrogen or organic compounds as the electron
donor in the absence of hydrogen sulfide/ |
Weight
per Gallon
Weight per Liter |
8.34
lbs
2.2 lbs. |
Specific
Gravity @ 77° F
Specific Gravity @ 25° C |
1.0
1.0 |
Boiling
Point ° F
Boiling Point ° C |
208°
98° |
Flash
Point ° F
Flash Point ° C |
>
200°
> 93.3° |
| Odor |
Slight
H2S odor |
| Color |
Clear
to light gray |
| Toxicity |
Non-toxic,
non-hazardous. Good housekeeping procedures
and general principles of safety should be
observed. |
| First
Aid |
Skin
contact - in cases of prolonged skin contact,
wash off with soap and water. If any
irritation exists, seek medical advice.
Eye contact - wash eyes with lots of water for
at least 10 minutes and seek medical advice. |
| Packaging |
55
U.S. gallon drums, bulk |
| Shelf
Life |
36 months or more in proper storage conditions. |
| Storage |
Protect
from freezing. Do not store in temperatures
above 108° F, 42 ° C, nor in direct
sunlight. |
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Our only obligation shall be to
replace or pay for any material proved
defective. Beyond the purchase price of
materials supplied by us, we assume no liability for
damages of any kind and the user accepts the product
"as is" and without warranties, expressed or
implied. The suitability of the product for an
intended use shall be solely up to the user.
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