THE SUPREME COURT OF APPEAL
REPUBLIC OF SOUTH AFRICA

JUDGMENT

Not reportable

CASE  NO: 655/06

In the matter between :

BUCKMAN LABORATORIES (PTY) LTD
Appellant

and

BROMINE COMPOUNDS LIMITED
Respondent

__________________________________________________________________________

Before:
STREICHER, NUGENT, HEHER JJA, HURT & SNYDERS
AJJA
Heard:
25 FEBRUARY 2008
Delivered:
28 MARCH 2008
Summary:
Patent – revocation in terms of s 61(1)(c) of Patents Act 51 of 1978
– absence of inventive step.
Neutral citation:
Buckman Laboratories v Bromine Compounds (655/06) [2008]
ZASCA 37 (28 March 2008)

__________________________________________________________________________

STREICHER  JA

STREICHER JA:
[1] In an action instituted by the respondent as the patentee of SA Patent
92/4018 in the court of the commissioner of patents (the court a quo) for relief
in respect of the alleged infringement of its patent by the appellant, the
commissioner of patents (Southwood J) ordered absolution from the instance
in respect of the appellant’s counterclaim for the revocation of the patent on
the grounds of lack of novelty and of inventiveness and interdicted the
appellant from infringing certain claims of the patent. With the leave of the
court a quo the appellant now appeals against the judgment.

[2] The patent is entitled ‘Process and Compositions for the Disinfection of
Waters’. Claim 1 of the patent reads as follows:
‘A process for killing microorganisms and controlling biofouling in high chlorine demand
circulating waters, which comprises mixing two components, one of which is an oxidant in
the form of a chlorine precursor in solution and the other an ammonium salt in solution
thereby forming a biocidal mixture, and adding the biocidal mixture immediately to the
high chlorine demand aqueous system to be treated.’
The claim can be divided into the following integers:
a)
A process for killing micro-organisms and controlling biofouling in high
chlorine demand circulating waters;
b)
Which comprises mixing two components;
c)
One of which is an oxidant in the form of a chlorine precursor in
solution;
d)
And the other an ammonium salt in solution;
e)
Thereby forming a biocidal mixture;
f)
And adding the biocidal mixture immediately to the high chlorine
demand aqueous system to be treated.’
Claims 2 to 13 are dependent on claim 1. Claim 14 is a separate independent
claim but has the same scope as claim 1 with the exception that the process is
limited to the treatment of circulating waters of paper industry systems.

Claims 15 to 26 are dependent on claim 14. The priority date of the patent is 3
June 1991.

[3] It is common cause between the parties that, in the event of the
respondent’s patent being valid, the appellant is infringing the patent in that
the appellant, at a number of paper mill plants, is using a process for
disinfecting water in which the features of claims 1, 2, 6, 10, 13, 14, 15, 19,
23 and 26 of the patent are present. The appellant, however, in its
counterclaim, claims that the patent is invalid for the reason that the invention
claimed in these claims was not new and did not involve an inventive step. As
stated above the court a quo dismissed the appellant’s counterclaim. In the
light of the conclusion to which I have come in respect of the question
whether claims 1 and 14 involve an inventive step I shall assume without
deciding that the court a quo’s finding in respect of novelty is correct and deal
only with the question of obviousness in respect of these two claims.

[4] In terms of s 61(1)(c) of the Patents Act 57 of 1978 a patent may be
revoked on the ground that the invention is not patentable under s 25. Under
s 25(1) a patent may not be granted to an invention which does not involve an
inventive step. In terms of s 25(10) an invention shall be deemed to involve
an inventive step if it is not obvious to a person skilled in the art, having
regard to any matter which forms, immediately before the priority date of the
invention, part of the state of the art by virtue of s 25(6). The state of the art,
in terms of that section, ‘shall comprise all matter (whether a product, a
process, information about either, or anything else) which has been made
available to the public (whether in the Republic or elsewhere) by written or
oral description, by use or in any other way.’

[5] The court a quo described the relevant art as the ‘disinfection of high
chlorine demand circulating waters’. In my view this description of the
relevant art is too restrictive. Professor Cloete, the head of the Department of
Microbiology and Plant Pathology at the University of Pretoria, testified that
the title of the patent namely ‘Process and Compositions for the Disinfection
of Waters’ was an accurate description of the art to which the patent relates
and his evidence in this regard was never challenged. The skilled addressee,
according to the court a quo, is a person with a tertiary qualification in
microbiology and chemistry. Neither the appellant nor the respondent took
issue with this finding.

[6] Regarding the state of the art at the relevant time the appellant relied on
various articles, amongst others: Hirschkind, Chloramine, Its Preparation,
Properties, and Uses Western Construction News, dated 25 October 1930;
Enslow, Ammonia-Chlorine Reactions and Chloramine Production – In
Water and Sewage Treatment Contract Record and Engineering Review,
dated 11 March 1931; Schirtzinger, Chlorine compounds for microbiological
control Paper Mill News, dated 29 July 1963; and Beck and others,
Preformed Monochloramine Used as a Post-Disinfectant in Drinking Water
Treatment at Sjælsø Water Works Aqua (1) 1986. The appellant also relied on
a number of patent specifications, amongst others: USA Patent No 1,378,644
titled Process of Sterilizing, dated 17 May 1921 (‘the Baker patent’); and GB
Patent No 1600289 titled ‘Sterilisation of Water for Nutrient Film Systems’
dated 26 August 1977 (‘the Wilson patent’). The respondent did not tender
any evidence while the appellant called Professors Cloete and Pretorius as
expert witnesses. Prof Pretorius obtained a DSc degree in the field of
microbiology from the University of Pretoria and an MSSan Engineering
degree from the University of California. Before his retirement he held the
chair of Water Utilisation in the Department of Chemical Engineering at the

University of Pretoria. In the light of these publications, the specification and
the evidence, the state of the art, in so far as it is relevant, can be summarised
as follows.

[7] Biological fouling of circulating water is a known and well documented
problem. It involves the growth of unwanted micro-organisms in water
systems. The unwanted micro-organisms include bacteria, fungi, protozoa and
algae. Such biological growth, according to the specification, can foul
pipelines, accelerate corrosion, attack wood, decrease heat transfer, plug
filters, cause imperfections in paper sheets, decompose sizing mixtures, and
cause many other process interferences. The micro-organisms can be killed
and the water can thus be disinfected by the use of oxidising biocides.
Chlorine is such an oxidising biocide and is widely used in circulating water.
It will kill or chemically incinerate the micro-organisms through an oxidation
reduction reaction.

[8] When chlorine is added to water the chlorine reacts with substances in
the water and is thereby reduced or converted to inert or less active forms of
chlorine.  Breakpoint is reached when a complete reaction has taken place
with all chlorine-reactable materials. The quantity of chlorine required to
reach this point ie the quantity of chlorine that is reduced or converted to inert
or less active forms of chlorine by substances in the water over a given period
is known as the chlorine demand of the water. Such demand is expressed as
the difference between the amount of chlorine applied and the amount of free
chlorine remaining at the end of the contact period eg 1.8 parts per million
(‘ppm’) out of 2.0 ppm chlorine after 60 minutes.

[9] When a chlorine precursor in solution, eg hypochlorous acid, is mixed
with an ammonium salt in solution, a chloramine is formed. Like chlorine,

chloramine is an oxidising biocide ie it will kill micro-organisms. Depending
on the pH level of the water three types of chloramine compounds can be
formed namely monochloramine, dichloramine and nitrogen trichloride. If the
pH is below 4.5 the dominant compound would be nitrogen trichloride, if it is
between 4.5 and 7.5 the dominant compound would be a dichloramine and if
it is above 7.5 it would be monochloramine. Chloramine is an effective
sterilizing agent and has the advantage that it remains unabsorbed for a much
longer period than free chlorine.

[10] The sterilizing effect of chloramines has been known since about 1910
and by the priority date of the patent a large amount of material had been
written on the effectiveness of chloramine compounds in water. In 1930
Hirschkind dealing with the preparation, properties and uses of chloramine
wrote that the low oxidation potential of chloramines causes them to persist
for a longer time than chlorine alone and makes their application possible in
cases where chlorine alone would be immediately used up by oxidation, as for
instance in industrial slimes. He stated that large dosages of chlorine, which
are sometimes resorted to, to take care of heavy bacterial loads or to kill
algae, and which may leave disagreeable odours and tastes, can be subsituted,
without these adverse side-effects, by chloramines alone. For most
commercial uses, he said, it may be found advantageous to prepare the
chloramine first and add it as such to the point of application. Dealing with
the production of chloramine by the reaction of chlorine with ammonia he
concluded that the pH level of the solution plays an important role in
stabilizing chloramine solutions and that if acid conditions are avoided the
chloramine decomposition is slow.

[11] In 1931 Enslow in his article on ammonia-chlorine reactions and
chloramine production in water and sewage treatment, stated that it may in

certain instances prove to be desirable to employ a ready prepared chloramine
solution in preference to the application of ammonia and chlorine separately.
He then described how monochloramine could be produced by adding an
ammonia salt in solution to hypochlorous acid, a chlorine precursor in
solution.

[12] In the specification of the Baker patent (1921) it is stated that the
inventor had found that in certain liquids such as sewage ie high chlorine
demand water, or other chlorine consuming liquids, sterilization may be
effected with a lesser proportion of nitrogen trichloride than would be
required of chlorine. The specification describes how nitrogen trichloride, a
chloramine, can be produced by mixing hypochlorous acid with an
ammonium compound such as ammonium sulphate, an ammonium salt, in
solution. Claim 2 of the Baker patent requires the solution so produced to be
utilised ‘immediately as produced as a sterilizing agent’. The respondent, in
oral argument before us, submitted that regard could not be had to the Baker
patent in that the appellant was not relying thereon. However, the Baker
patent is mentioned in the appellant’s counterclaim as one of the prior art
documents relied upon, respondent’s counsel dealt with the Baker patent in
his cross-examination of Prof Cloete, and, in their heads of argument,
respondents’ counsel referred to the Baker patent and stated: ‘It does not teach
the preforming of an unstable biocide and adding that biocide immediately to
the water to be treated.’

[13] In 1963 Schirtzinger, writing about slime control in white water
systems in the pulp and paper industry ie high chlorine demand circulating
waters, said that current water treatment practice used free chlorine rather
than combined forms of chlorine for microbiological control but that in white
water systems chloramines were more effective. According to him, the use of

chloramines will produce effective slime control at exceptionally low cost in
paper white water systems. Slime consists of a gelatinous mass caused by
bacteria, in which fungi and algae accumulate, propagate and become highly
objectionable. Schirtzinger stated furthermore, and Prof Cloete agreed, that
there is no resistance of any particular strain of microorganism to chlorine
compounds and that the combination of chloramines concentration and
contact time would destroy slime-forming organisms.

[14] Prof Cloete testified that it would be ‘a natural step to take an excellent
disinfectant technology [from waste water applications] and move it into other
applications [for instance paper mills, cooling towers and the like]’. Prof
Pretorius, referring to chloramines, testified that ‘the disinfectant that is
supplied is supplied to . . . virtually the whole spectrum of water that we are
using, whether it is waste water or drinking water or whatever it be, it is a
universal oxidant or a universal disinfectant’.

[15] The Wilson patent relates to the sterilisation of water in a system called
a nutrient film system in which plants are grown with their roots immersed in
a flowing film of liquid containing plant nutrients. In the specification the
system is described as follows: ‘Typically, a shallow waterproof trough is
formed and a film of aqueous nutrient solution flows through the trough, is
collected, e.g. in a sump tank, and recycled, e.g. to a header tank, from
whence it is fed back to the trough. During the cycle, water and nutrients are
taken up by the plant and these require replacement before the nutrient
solution is recycled.’ The nutrients consist of a water soluble fertilizer
composition. According to the specification chlorine can be used as the
sterilizing agent and in this regard it is said that chloramines provide a
particularly preferred form of available chlorine since they have a slower
action than uncombined available chlorine. The chloramine is conveniently

formed in situ in the water or in a separate vessel from which it is dosed at the
desired rate into the water. Where an aqueous solution of the pathogenicide is
being dosed this may be done by any suitable means eg by feeding it to the
throat of a venturi in the water feed line or into the circulating nutrient
solution in the nutrient film system. Claim 1 of the Wilson patent reads as
follows:
‘1.
A process for treating water fed to or circulating in a nutrient film system which
comprises incorporating a plant physiologically acceptable amount of a
pathogenicide into the water.’
In terms of claim 5 the pathogenicide is a chloramine, in terms of claim 10 a
preformed pathogenicide may be added and in terms of claim 12 a preformed
pathogenicide may be fed to the water in association with fertilizer
ingredients.

[16] Professor Pretorius testified that a nutrient film system such as the one
discussed in the Wilson patent, will have a high chlorine demand. According
to his evidence, anybody that is knowledgeable about these systems knows
that any plant growing in water is liberating organic material from the root
phase which accumulates in the water as humus and causes a high chlorine
demand apart from the nitrogen introduced as a nutrient as well as any
microorganisms or pathogens that may develop. This evidence was never
challenged in cross-examination. Counsel for the respondent put to him that
‘the document does not describe how to get to the arithmetic . . . to determine
if it is high or low chlorine demand’ and Prof Pretorius agreed. He also agreed
that in the case of the mixing of a chlorine precursor with fertilizer containing
an ammonium salt in a separate chamber before addition thereof to the
circulating water, the chlorine demand is created by the fertilizer. However,
his evidence that the system would have a high chlorine demand for the other
reasons given by him, was left unassailed.

[17] Beck, writing in 1986, in dealing with the use of preformed
monochloramine as a post-disinfectant in drinking water treatment, described
how a stable monochloramine could be produced by the use of ammonium
sulphate and hypochlorite solutions.

[18] It follows that as at the priority date of the patent it was well
documented that a biocidal mixture (chloramine) could be formed by mixing
two components consisting of an oxidant in the form of a chlorine precursor
in solution and an ammonium salt in solution and that such biocide could be
used to kill microorganisms and to control biofouling in high chlorine demand
circulating waters by adding the biocidal mixture to the high chlorine demand
aqueous system to be treated. This is the process described in claim 1 and 14
with only one exception and that is that according to these claims the biocidal
mixture must be added immediately. In the cross-examination of the
witnesses it was repeatedly stressed by the respondent’s counsel that, in the
processes being referred to, it was not said that the chloramine had to be
added immediately after its formation. However, in the case of the Baker
patent immediate addition of the chloramine is required because of the
volatitilty of nitrogen trichloride.

[19] Professor Cloete, referring to the claims of the patent, testified that he
did not know what the inventive step was as all that has been said was known.
Professor Pretorius’ evidence was to the same effect. In regard to the
requirement that the biocide be added immediately Prof Cloete  testified that
he did not ‘think that there would be any disadvantage of adding it
immediately’ and that ‘when you produce any compound and particularly
where you are dealing with oxidising biocides, which are generally less stable
than non-oxidising biocides, you would actually want to get them into your
water system as soon as possible. . . .the maximum efficacy you will actually

get just after you have actually made the product and I would argue that it . . .
makes common sense’.

[20] Notwithstanding the fact that the inventor, Dr Ayala Barak, was
available to testify and that a summary of the expert evidence that she would
give had been delivered, the respondent did not call her as a witness. The
court a quo nevertheless had regard to her summary to determine what the
inventor claimed the inventive step to be and concluded: ‘Thus, according to
the summary, the process of the invention, contrary to the conventional
wisdom of the time, deliberately aims to produce an unstable biocide. It is
because of that instability that the biocide mixture is added to the aqueous
system to be treated immediately.’

[21] Dealing with the contention that the process of the invention
deliberately aimed to produce an unstable biocide the court a quo said that if
that was the aim of the invention ‘this seems to be essential to an
understanding of the invention and required emphasis to show why the
biocide is added immediately to the high chlorine demand aqueous system.
The absence of any reference to the biocide being unstable is indicative of this
not being the case. The evidence relating to the examples in the 1995 patent
seems to put the matter beyond doubt.’

[22] The reference to the 1995 patent is a reference to South African Patent
95/8275 which is also in respect of a method of treating liquids to inhibit the
growth of living organisms and in respect of which the inventor is also stated
to be Ayala Barak. According to the specification the decomposition rates of
various biocidal mixtures were monitored and in the case of a concentrated
solution of ammonium sulphate (an ammonium salt) and sodium hypochlorite
(a chlorine precursor) the rate of decomposition of the active biocidal

ingredient (a chloramine) was found to be relatively stable for a period of two
and a half hours.

[23] In regard to counsel for the respondent’s submission that ‘adding the
biocide formed immediately to the aqueous system to be treated was at least
part of the inventive step of the patent’, the court a quo held:
‘Chlorine (chlorination) and chloramines (chloramination) had been used for the
disinfection of water and water systems for about 80 years when the patent was granted.
Notwithstanding extensive use in paper mill systems which obviously include high
chlorine demand circulating waters, the literature dealing with the processes used does not
suggest the combination of the integers of the plaintiff’s invention to deal with the
microorganisms and other matter found in the water and the circulating waters. The
evidence does not suggest that any other similar process was conceived to deal with the
problems experienced in the paper mills. Whatever the position with regard to the
instability of the biocide produced it seems clear that the invention works. In these
circumstances it seems that the selection of the two components, the mixing of these
components (both in solution) outside the aqueous system to be treated and the immediate
addition of the biocide constitutes the scintilla of the invention required.’

[24] Before us counsel for the respondent submitted that the combination of
all the integers of the invention constituted the inventive step. The
conventional wisdom at the priority date, so he submitted, taught the
production of a stable biocide that has a lasting disinfecting effect while the
patent on the other hand, aims at creating an unstable biocide that is highly
efficient when added immediately.

[25] On the evidence it is clear that chloramines of varying stability can be
produced. The patent makes no mention of the stability of the biocide.
Stability of the biocide is therefore not a feature of the patent at all. At the
priority date it had been stated in various publications that chloramines could
be used to sterilize high chlorine demand circulating waters, including paper

industry systems and that preformed chloramines could be used to treat high
chlorine demand water such as sewage and also high chlorine demand
circulating waters. It follows that ignoring the Baker patent as respondent’s
counsel urged us to do, the inventive step could only have been the immediate
addition thereof. However, according to Cloete, where you are dealing with
oxidising biocides which are generally less stable than non-oxidising biocides
and whose efficiency would be at its maximum just after you have made them
it makes common sense to add them immediately. No reason was suggested
why anybody would have thought that one should not add the preformed
chloramine immediately. In these circumstances it is in my view obvious and
would, as at the priority date, have been obvious to a person skilled in the
relevant art, that preformed chloramine could be added immediately or,
depending on its stability, later.

[26] The fact that the process described in the patent, on the priority date,
had not been used in paper mill systems notwithstanding extensive use of
chloramines in such systems and notwithstanding the use of chloramines for
the disinfection of water for about 80 years does not assist the respondent. It
had been stated that it could be done and that statement proved to be correct.
The fact that the process works, therefore, does not assist the respondent
either.

[27] It follows that the invention embodied in claims 1 and 14 lacked an
inventive step and that the patent should for that reason not have been
granted.  We were asked to also deal with the claims dependent on claims 1
and 14 but that may be an academic exercise on which we do not wish to
embark.

[28] The respondent asked and the appellant did not object that, in the event
of it being held that the patent is invalid, it be afforded an opportunity to
apply for the amendment of the patent.

[29] The following order is made:
a)
The appeal is upheld with costs including the costs of two counsel.
b)
The order made by the court a quo is replaced with the following order:
(i)
The plaintiff’s action is dismissed with costs including the costs
of two counsel.
(ii)
The defendant’s counterclaim for the revocation of SA Patent
92/4018 is granted and, subject to what is ordered in
subparagraph (iii) below, the patent is revoked.
(iii)
The revocation order granted in subparagraph (ii) is provisional.
It will become fully operative in respect of the patent concerned,
if the patentee does not within one month file notice of an
application to amend such patent, or if having filed such
application, the patentee withdraws it. If an application as
aforesaid is made and not withdrawn, it shall be decided at the
hearing of such application whether or not the revocation order is
to be put into operation.
(iv)
The plaintiff is ordered to pay the defendant’s costs in respect of
the counterclaim including the costs of two counsel.

__________________
P E STREICHER
JUDGE OF APPEAL
CONCUR:
NUGENT JA)
HEHER JA)
HURT AJA)
SNYDERS AJA)

THE SUPREME COURT OF APPEAL
REPUBLIC OF SOUTH AFRICA

MEDIA SUMMARY – JUDGMENT DELIVERED IN THE SUPREME COURT OF APPEAL

From:
The Registrar, Supreme Court of Appeal
Date:
28 March 2008
Status:
Immediate

BUCKMAN LABORATORIES (PTY) LTD v BROMINE COMPOUNDS
LIMITED

Please note that the media summary is intended for the benefit of the media
and does not form part of the judgment of the Supreme Court of Appeal.

* * *

The Supreme Court of Appeal today (28 March 2008) held that SA Patent
92/4018 entitled ‘Process and Compositions for the Disinfection of Waters’ is
invalid in that it did not involve an inventive step.