1. Oil & Gas Industry
CleanOxide 75 - Applications
in the Oil & Gas Industry
CleanOxide 75 is a practically pure solution of
chlorine dioxide – one of the most powerful
and safe disinfectants known as well as a highly
effective oxidising agent for converting sulphide
to sulphate.
Chlorine dioxide is also very efficient at oxidising sulphides to
sulphate; thus, providing a method of simultaneously controlling
sulphur reducing bacteria and removing sulphides.
Sulphides are formed by the action of sulphate reducing bacteria
found in oil well systems. The sulphides react with iron in the
water to form insoluble iron sulphide that in conjunction with
bacterial biofilm acts as a plugging agent.
The presence of sulphides also causes what is known as sour
crude which is of lower quality and more expensive to refine.
Controlling sulphide levels in oil and gas wells is not only
necessary for ensuring a higher quality product and to minimise
plugging, it is also necessary for the protection of personnel from
exposure to extremely toxic hydrogen sulphide gas.
CleanOxide 75 can also be used in place of or in addition to
conventional biocides to control bacteria in drilling mud and
hydraulic fracturing fluids, downhole cleaning of injection and
disposal wells, and as an emulsion breaker.
CleanOxide 75
CleanOxide 75 from Activ8H2O is the simple modern
method of generating high purity chlorine dioxide as
and when required by mixing two precursor
solutions (see Natural Water Solutions brochure
CleanOxide 75 for more information).
CleanOxide 75 is a 0.75% solution of chlorine
dioxide in water containing only a small amount of
sodium sulphate and sodium chloride as by-products
of mixing.
The precursor solutions have a shelf life of at least
two years when stored in a cool, dry place out of
direct sunlight.
Advantages of CleanOxide 75
• CleanOxide 75 is effective over a broad pH
range (4-10).
• CleanOxide 75 controls bacteria, bacterial spores,
fungi, viruses, biofilm, protozoa and algae.
• CleanOxide 75 does not react with ammonia and
does not produce toxic compounds in contact
with organic materials present in water.
• CleanOxide 75 is not toxic at the recommended
dose rates.
• CleanOxide 75 rapidly degrades to harmless
inorganic chemicals when used at the
recommended dose rates.
• CleanOxide 75 does not contribute to corrosion.

2. Corrosion
The use of oxidising biocides such as
hypochlorite and ozone is associated with
increased rates of corrosion.
Chlorine dioxide generated by traditional methods also
suffers from this problem because of free chlorine and other
corrosive by-products formed in the manufacture.
Chlorine dioxide itself is not a corrosive substance.
CleanOxide 75 is a solution of pure chlorine dioxide.
CleanOxide 75 does not contain any corrosive by-products
nor does it breakdown to form any corrosive compounds.
Even at elevated levels, the use of CleanOxide 75 will not
result in increased corrosion.
For further information, see Activ8H2O Technical Data Sheet
Chlorine Dioxide – Corrosion Data.
Control of Biofi lm
CleanOxide 75 controls biofilm more effectively than chlorine
or non-oxidising biocides even when dosed intermittently.
The reason why CleanOxide 75 is so effective at controlling
biofilm. because it is a solution of pure chlorine dioxide
in water.
Chlorine dioxide does not hydrolyse in water and does not
react with the polysaccharides holding the biofilm together.
Consequently, it is able to diffuse deep into the biofilm layers
destroying the microorganisms that are present (for further
details, see Activ8H2O Technical Data Sheet Control of Biofilm
with CleanOxide 75).
Non-oxidising biocides are generally ineffective at controlling
biofilm.
Environmental Impact of CleanOxide 75
The environmental impact of chemical discharge is of major
concern to the oil and gas industry. CleanOxide
75 has a much lower impact than alternative chemicals for a
number of reasons:
• CleanOxide 75 can replace the use of persistent organic
compounds such as biocides and hydrogen sulphide
scavengers. Many non-oxidising biocides such as
isothiazolines are extremely toxic compounds and often of
relatively low biodegradability.
• CleanOxide 75 is extremely efficient and thus reduces
overall chemical demand.
• CleanOxide 75 does not form organochlorine compounds
by reaction of organic compounds with chlorine.
Organochlorine compounds are both suspect carcinogens
and known persistent pollutants.
• CleanOxide 75 does not form chloramines by reaction
with ammonia.
• CleanOxide 75 has no potential to bioaccumulate.
• CleanOxide 75 degrades rapidly at the recommended dose
rates (typically <72hours) to harmless inorganic compounds.
Dose Rates
Oxidation of Sulphites
The optimum dose rate of CleanOxide 75 will depend on many
factors including water quality, the degree of contamination
present and the details of the application. In general, the
performance of CleanOxide 75 is unaffected by pH or the
presence of other organic matter.
If CleanOxide 75 is dosed continuously at a rate slightly higher
than the sulphides oxidative demand as determined by a
demand study.
For intermittent treatment, CleanOxide is applied at a much
higher rate from 200 to 3,000mg/L depending on the sulphide
level and frequency of treatment.
Ideally, CleanOxide is dosed into the system where good
mixing and uniform distribution is achieved. In some cases,
multiple treatment points may be required. To prevent
volatilisation of chlorine dioxide, the feed point should be
below the water level.
Residual chlorine dioxide in the waste water is rapidly
biodegraded to harmless inorganic materials. Consequently
disposal of waste water poses no environmental hazard.

3. 0.1 to 0.3mg/L for potable water. Higher dose rates (up
to 3mg/L or higher) may be used for other applications
depending on the quality of the water, bacterial loading and
degree of control required.
If the water to be treated is high in sulphides then the dose
rate is calculated according to the sulphide demand and
a residual concentration of chlorine dioxide for control of
biological contamination.
To calculate the dose rate of CleanOxide 75 use the following formula:
Dose Rate (L/hr) =
For example, if the flow rate is 25L/s and the sulphide concentration is 2mg/L, the target
chlorine dioxide concentration is 4.2mg/L and the dose rate is,
= 50.4L/hr
If the flow rate is expressed in m3
/hr, the formula becomes,
Dose Rate (L/hr)
For example, if the flow rate is 150m3
/hr and the target concentration is 4.2mg/L, the dose rate is,
= 84L/hr CleanOxide 75
System flow (L/s) x Target concentration of chlorine dioxide (mg/L) x 3600
7500
= System flow (m3
/hr) x Target concentration of chlorine dioxide (mg/L) x 1000
7500
= 25 x 4.2 x 3600
7500
= 150 x 4.2 x 1000
7500
In the reaction of chlorine dioxide with sulphides, one equivalent of sulphide is consumed by one equivalent
of chlorine dioxide. For calculation purposes, this equates to 1 part by weight of sulphide is consumed by 2.1
parts by weight chlorine dioxide.
To calculate the dose rate of CleanOxide 75 use the following formula:

4. discuss your specific requirements.
Please Note: The information contained in this document is based on CleanOxide 75 pure chlorine dioxide and is
not applicable to other sources of chlorine dioxide.
The following tables give the approximate concentration of chlorine dioxide obtained when freshly
prepared CleanOxide 75 is diluted with potable water.
Actual concentrations obtained will depend on the age of the CleanOxide 75 solution and the quality
of the water.
Once diluted for use, solutions should be used immediately.
For further advice on applications of CleanOxide 75, contact Activ8H2O to discuss your specific
requirements.
CleanOxide 75 Part A and CleanOxide 75 Part B are available in 18L/2L, 180L/20L and 900L/100L
CleanOxide Part A (P) and CleanOxide Part B for professional users are available in 1000L pack sizes only.
CleanOxide 75
per 1000L water
Chlorine Dioxide
Concentration
CleanOxide 75
per 1000L water
Chlorine Dioxide
Concentration
2.5L 19mg/L 0.5L 4mg/L
1L 7mg/L 0.25L 2mg/L
0.75L 6mg/L 0.05L 0.4mg/L
For further advice on applications of CleanOxide 75, contact Activ8H2O
specific requirements.
M: 0430 543 439
E:darren@activ8h2o.com.au
www.activ8h2o.com.au