SAVING THE SCRAP FROM THE SEA
If the human race be extravagant in one, more than in any other
direction, it is undoubtedly in connection with the utilization of
the harvests of the sea. It is a failing as strongly asserted by the
primitive as by the cultured races. The aborigine, when there is a
big run, will trap as many fish as he can, not for consumption, but
apparently for the mere sake of catching his prey. He will select what
he requires and leave the remainder to rot. His civilized brother
pursues a broadly similar course, only in this event decomposition may
not be permitted to run its course without fulfilling a beneficial
purpose. The process can be harnessed, as it were, to a more or less
useful function.
Improvidence in the consumption of fish is particularly noticeable
among those nations which are able to point to an extensive salt-water
front, combined with a densely-settled population within a relatively
small area. It becomes accentuated when the country is possessed of an
intricate and excellent system of rapid inland transportation, allowing
the prompt movement of the catches from the points of landing to the
centres of consumption.
Such a country is Great Britain. With us fish is an exceedingly cheap
food and one which, normally, is readily procurable in adequate
quantities. The “long haul” by rail occasions no apprehensions,
inasmuch as the railway transport problem, so far as fish is concerned,
has been magnificently solved, it being possible to move consignments
four hundred, even six hundred miles within a few hours.
The sea’s contribution to the table is prolific. At the same time
it is variable. This factor in itself conduces towards pronounced
wastage. We seem to have failed lamentably in our efforts to cope with
the alternating spells of plenty and relative scarcity in a scientific
manner. We have not mastered the adjustment of seasonal gluts, arising
from the periodic massed movements of the fish, to shortages in order
to maintain a steady and uniform supply the whole year round. In view
of the immense strides which have been made in the art of preserving
perishable foodstuffs, this deficiency is certainly somewhat remarkable.
The extremely low prices at which the bulk of the food from the sea,
particularly of herring and sprat--occasionally mackerel--is available,
are primarily responsible for the extravagance which rules. This
state of affairs offers another interesting illustration of the fact
that extremely cheap living promotes waste. We need only to recall
the experience of the war to assure ourselves upon this point. Under
the system of price control, coupled with abnormally high rates, fish
purchases had to be conducted by the trade with extreme caution to
obviate financial losses, while, similarly, the consumer was compelled
to be more economic and less fastidious in his, or her, tastes. Under
such conditions far less of the single fish was wasted, while greater
ingenuity was exercised in the preparation of the less attractive
edible portions for the table.
Nevertheless, no matter how extreme the care or economy manifested, a
certain degree of wastage is unavoidable. For the most part the offal,
which in itself is appreciable in volume, is regarded as irreclaimable
and valueless except as a fertilizer. But this reasoning is fallacious.
Fish-waste is capable of furnishing raw material in several forms to
feed other industries. As yet this notable circumstance has not become
fully appreciated in these islands, the practicability of using such
refuse only having been established during the past few years.
Ability to turn fish offal to distinct profitable advantage not only
solves the problem in its economic aspect, but at the same time
indicates a promising outlook for glut catches and to which the
ordinary markets are often denied. In this country the conventional
disposal of surplus fish is decidedly deplorable for the reason that it
follows the line of least resistance. A glut or late catch is generally
sold at an absurd price in bulk to serve merely as manure.
If the fish could be turned directly into the soil such a use might
not be exposed to severe condemnation, although it is to be deprecated
because it represents a serious misuse of valuable food. But, as a
rule, this cannot be conducted with the essential promptitude for
obvious reasons. Then the farmer suffers a heavy loss. Vigilant gulls
and other birds having a well-defined penchant for fish diet raid the
land to enjoy a Gargantuan feast with the minimum of effort on their
part. The birds will even follow a train, or road wagons, bearing a
manurial consignment of their food, for miles from the point of landing
and then, after it has been dumped, will swoop down to gorge themselves
to the full. In many instances a farmer has been known to lose at least
50 per cent. of his purchase in this manner. He may essay alert and
effective measures to combat the birds’ attacks, but he will find it
an unequal contest. In one instance, which came before my notice, the
insatiable birds, catching sight of one or two open trucks laden with
a freshly-landed catch _en route_ to the land, attacked the wagons so
vigorously as to cause a very perceptible shrinkage in the load before
it reached its destination. Another farmer, who had been persuaded to
buy two or three truckloads of freshly-landed fish just because it was
cheap, subsequently expressed his doubt as to whether he had driven a
good bargain after all. The birds attacked the field over which the
loads were distributed in such overwhelming numbers as to prompt the
opinion that the field really contained more gulls than fish! So, after
all, it is extremely questionable whether the purchase of a bumper
catch for use as a fertilizer is really such a bargain as it may appear
from a cursory reflection.
In our large cities and towns the treatment of fish offal and surplus
supplies drawn from the markets, stores, and retail shops, as well as
the hotels, restaurants, and clubs, for industrial exploitation, should
present no difficulty whatever. It is an offal apart and a noisome one.
Its susceptibility to rapid decomposition and the emission of obnoxious
odours during the process demand its prompt removal. It cannot be
handled with other refuse owing to its offensiveness. Consequently the
system of special collection by vehicles of the closed tank type has
become the general practice. In this manner the disconcerting factor
pertaining to the utilization of organic waste--effective segregation
at the source--is assured.
Although, so far as we are concerned, the record of practical
achievements concerning the industrial utilization of fish-waste is
slender, owing to the few firms having been persuaded to embrace this
phase of trading, it is consoling to learn that we possess what may be
described as the leading authorities competent to deal with this issue
in all its varying aspects, and to be equipped with the best approved
facilities for conducting this work along the latest and most promising
lines. There is one firm in particular which has built up a unique
reputation in this direction, having been responsible for the design
and construction, as well as installation, of the largest fish-waste
reclamation plants in operation throughout the world. Some of these
equipments are most elaborate in character, and their very dimensions,
activity, scale of operations and prosperity, serve to demonstrate, in
the most convincing manner, the enormous wealth capable of being won
from fish scrap when the task is conducted along the lines advanced
by scientific development. The British firm in question, to whose
apparatus I have devoted extensive description in a previous chapter,
has been responsible for the complete installations forming part and
parcel of the huge canneries scattered along the western seaboard of
the North American continent.
It somewhat redeems our own short-sightedness and lack of enterprise to
know that we have a firm in our midst which has achieved many distinct
triumphs in the great issue of waste reclamation. It retains an
imposing staff of highly-trained chemists who have become specialists
in this privileged province, and they have devoted especial attention
to the exploitation of fish-scrap in the anticipation that this may
yet develop into a pretentious British industry. The presiding genius
of this organization has also associated himself intimately with
the problem from the severely scientific side, as well as becoming
thoroughly familiarized with the latest methods as practised in
Germany, Scandinavia, and other countries in order to reap full
advantage from the lessons which they are able to extend in point
of equipment and practice. In the opinion of this active-minded and
enterprising authority we have nothing to learn from the foreigner
either in point of processes, plant, or efficiency. We merely lack the
necessary imagination, initiative, and commercial acumen to be able to
reap the full financial and trading harvest to be gathered from the
exploitation of fish-scrap. While we are apathetic and backward in this
connection our Dominions are alert and astute. We need only to turn to
the extensive installation recently laid down in Australia--a model of
its type--and which was completed by the firm in question, to grasp
what can be accomplished in this peculiar field.
It was extremely fortunate for us, as a nation, to be possessed of
the knowledge and creative resources of a progressive firm. During
the war, when the economic conditions became so tense, the question
of the economic disposal of fish-waste to full commercial advantage
suddenly assumed an unexpected significance. Specific raw materials
were urgently demanded, and it was decided to search sedulously
for additional domestic sources of supply. In the conduct of these
investigations the potentialities of fish-scrap were forced to the
forefront. The enemy was exploiting this field to its absolute limits,
so why should we continue to ignore it? Cognizant of the precise
possibilities of this industry and the financial attractions which it
possessed the head of the firm of which I have written expressed his
readiness to extend all assistance in his power. His knowledge of the
craft, together with that of what the enemy could and could not do,
proved invaluable, and enabled us to place the recovery of the wealth
from this waste upon a solid foundation, and in such a manner as to
allow of its indefinite expansion in the future.
So far as turning fish-scrap to commercial account has been concerned
in these islands the axiom pertaining to the prophet and his own
country has not been wholly applicable. The Germans endeavoured to
establish an industry upon this raw material among us but signally
failed. One or two small plants were laid down along the broad lines
in vogue upon the other side of the North Sea, but they fell so far
short of expectations or requirements, and were so strikingly inferior
to British thought as to fall into disuse. They have long since been
broken up.
The Teuton, however, was not solicitous of the welfare of the British
nation in exploiting British fish-waste. He was merely prompted to
plant himself here because the necessary refuse--raw material from
his point of view--was obtainable in such huge quantities and at a
low figure. The output was shipped to Germany, where it commanded an
attractive price and was in keen demand. The spurned and rejected of
Britain became the highly prized of Germany.
Fish-waste falls into two broad classes, which are yet somewhat sharply
defined. These are white fish and oily offal respectively, the herring
being the best example of the latter category. Consequently, to conduct
fish-waste reclamation and exploitation for the by-products upon a
sufficiently comprehensive scale in these islands it would be necessary
to separate the offal into the two distinctive classifications at
the source. However, this would not be such a perplexing problem as
it might appear at first sight. Such segregation is imperative for
specific technical reasons, while one must also remember that the salt
content of the offal varies widely in the two classes of fish.
Scrap of this character can be induced to yield three commercial
products as a result of inexpensive treatment. They are respectively
meal for poultry and cattle, oil, and fertilizer. A fourth commodity
might be included, namely, fish-glue. Hitherto we have been content to
draw upon other countries for our supplies of this article, although
abundant raw material for its production has always been readily
obtainable. But manufacture was doubtless regarded as being extremely
speculative for the simple reason that the demand for this article
was severely limited. For some reason or other fish-glue, though
extensively used by the peoples of other nations, has never been
regarded with pronounced favour in British circles although it cannot
be excelled as an adhesive. Probably its peculiarly pungent odour has
been responsible for our indifferent appreciation of its virtues. One
or two small factories were equipped to conduct domestic manufacture,
but they were far from being pretentious in their scale of operation.
Fish-glue has attained its greatest vogue in Germany, Scandinavia,
Canada, and the United States of America--the last-named more
particularly. Yet there is no reason why it should not become equally
popular here. All that is required is to enlighten the community
concerning its properties, and here is a grand opportunity for
propaganda in support of a new industry. There is no secret associated
with its production as might possibly be imagined. The quality most
essential to secure its widespread appreciation is merely a display of
grim energy, push, and go. It is not a case of being called upon to
advance the claims of an entirely new product. It is known more or less
throughout the country from the circumstance that it is being exploited
in varying degree throughout the world. In these circumstances the
manufacture of British fish-glue from British fish-waste presents
enormous possibilities, capable of illimitable development.
There are signs that we are bestirring ourselves in this direction.
Heretofore fish-glue has always been made from the skins of white fish.
It has now been suggested that, in this country, the bones might be put
to similar account, the gummy content thereof being quite pronounced.
Expert opinion favours the contention that such might be carried out
to advantage, but there is one supreme difficulty--the adequate supply
of the essential bones. They could be drawn from the filleting trade,
but the extent of this supply is somewhat problematical. Fish-bones as
such have not yet attained the high estate of recognition as a distinct
article of commerce. Nevertheless a possible way out of this difficulty
has been suggested. It should be quite practicable, when employing the
oil extraction process to which I refer later, to sift out the larger
bones before submitting the dry residue to the grinding process. In
this way it would be possible to secure a ready supply of the necessary
raw material for the production of the glue.
It has also been suggested in certain home circles that herring
offal might be treated in such a way as to yield fish-glue, but this
represents a venture upon untrodden ground. From such a statement it
must not be inferred that this residue could not be induced to yield
the substance desired, but so far as is known the offal has never
been devoted to this purpose. Nevertheless, the suggestion is to be
applauded. It is indicative of the new spirit attending the disposal of
fish offal and goes to prove that British commercial pioneering is far
from being numbered among the lost arts. The mere launch of the inquiry
has sufficed to spur the chemist to investigate the problem, and any
success achieved in the laboratory in this direction will represent
an enormous progressive stride owing to the magnitude of our herring
fishery.
At the moment it is the recovery of the oil, meal, and fertilizer
which constitutes the primary objectives of the industry. Of the three
possible by-products the meal is doubtless the most remunerative.
To a certain degree the contemporary concentration of effort upon
the conversion of the offal into meal is due to the fact that this
constituted the essence of German endeavour in these islands before
the war. This meal was in keen demand in Germany, and the bulk thereof
was dispatched to that country and Japan. The interruption of this
supply to the former, as a result of the outbreak of hostilities, hit
the enemy somewhat severely. Not only was he thus deprived of the
crude meal prepared in Britain, but he was also denied the opportunity
to turn the waste accruing from the consumption in the Fatherland of
the heavy imports of British herring which were also summarily cut
off. Doubtless Germany cherishes hopes that her industrious sons, who
specialized in this distinctive craft, will be permitted to return to
the scene of their former labours and to exploit British fish-scrap
once again to the advantage of the German nation upon the conclusion of
peace. May the wish become no more than father to the thought. We have
not failed to profit from the many lessons taught by the war: we have
been forced to recognize the many virtues of fish-meal and have made,
and still are making, spirited efforts to repair the losses in this
line of trading which, from our indifference and lack of imagination,
we lost.
To galvanize British effort the fish-meal and fish-manure (guano)
manufacturers have joined hands. Propaganda has been waged vigorously
by the association, while agricultural societies and colleges have
willingly co-operated to spread the gospel of enlightenment. Farmers
have been canvassed sedulously, and the value of these by-products
for feeding stock and soil have been brought convincingly before
them. As a poultry food fish-meal is declared to be unsurpassable,
and this circumstance has been driven well home. The result of this
onslaught has been to force the farmer, an admittedly difficult
individual to convince, into the admission that these products are
possessed of far-reaching potentialities, the result being that,
to-day, an increasing demand for fish-meal and guano prevails, which
has exercised the obvious effect of stimulating the exploitation of
fish-scrap to a very pronounced degree.
During the war circumstances militated against the fulfilment of any
impressive programme of development along modern lines. Plant and
machinery could not be procured owing to the prior claims advanced by
other industries. Consequently the problem became resolved rather into
the modernization and adaptation of existing plants, many of which
suffered from being woefully inefficient. But even in this direction
much was achieved which cannot fail to be of distinct value, since it
has served to illustrate what can be done in this field to financial
profit. Now that trade is returning to the normal we may safely
anticipate a striking advance along the whole industrial line in the
installation of comprehensive plants coinciding with the very latest
expressions of scientific thought, and which will not fail to conduce
to the winning of impressively additional wealth from this hitherto
sadly-neglected material.
So far as the white fish is concerned the conversion of the offal
into meal represents a straightforward operation. It is merely dried
under vacuum along the lines already described, a steam-jacketed
drier or concentrator being used for the purpose. If the waste be
stale or heavily impregnated with salt it cannot be used as food, the
product in this instance being bagged for sale as a fertilizer. But
the manufacturer, owing to the enhanced profit to be derived from the
sale of the product in the feeding-meal form naturally strives to
secure this article, and so, if designed for this use, the meal, after
issuance from the drier, is passed through a disintegrator and is then
graded through a sifting reel.
It is the exploitation of the herring and the sprat, both in the form
of offal, glut catches, and condemned consignments, which presents the
most attractive future in these islands. When it is remembered that
the annual yield of the sea to the fishermen of Britain represents
a round 4,000,000,000 herrings, it will be conceded that here must
be a Klondyke of waste. Unfortunately, however, the issue is not so
straightforward as it would seem to be. An enormous quantity of the
catches are set aside for salting and curing to allow of export to
foreign markets. In the past Russia and Germany were our largest
customers for this foodstuff, their combined purchases running to
a round 800,000,000 lb. and exceeding £4,000,000--$20,000,000--in
value. When the fish is salted the treatment of the offal presents a
rather teasing problem. Its excessive salt content reacts against its
conversion into poultry-meal except in very small quantities which are
almost too insignificant to demand attention. When a fish-meal carries
salt in excess of 5 per cent. it can be used as a constituent of
blended or compounded foods, and then only sparingly. Consequently the
possible consumption in this field can only be relatively trifling.
By salting the herring the saline content is increased to 20 or even 25
per cent., and the removal of the added salt offers a supreme obstacle.
Fortunately it crops up only at certain seasons, but, at these periods,
the quantities of offal and scrap to be treated assume imposing
dimensions. As may be imagined, from what has been related, salt is
the bugbear to the meal manufacturer and he is hard put to it to bring
the figure down to one coinciding with trading requirements. What he
desires is a simple, inexpensive process whereby the excessive salt may
be eliminated without impairing the other virtues of the material in
any way. Needless to say the discovery of such a preliminary treatment,
meeting with his desires, will be received with unfeigned delight.
The suggestion has been advanced that the extraneous, or added,
salt might be removed by subjecting the offal to a washing process.
Undoubtedly, in this way, the desired end could be consummated to a
certain degree, but, at the same time, there is the danger that the
water would not only carry away the salt but would bear with it an
appreciable proportion of the valuable nitrogenous matter which it is
imperative should be retained. Unfortunately the salt is not completely
free; it permeates the fish through and through and is held by the
tissues. In view of the difficulty obtaining the manufacturer, as
a rule, converts the heavily salted offal into fertilizer, but the
enhanced salt content of the manure is regarded with certain misgivings
even by the farmer.
This problem assumed its maximum intensity during the war. Huge
quantities of barrelled herrings, destined for export to the countries
upon the other side of the North Sea, were held up by the authorities,
who feared that they might ultimately find their way into enemy
countries. As there was no other outlet for this produce, the salted
herrings not being regarded with favour here, these prohibited exports
were ultimately thrown upon the hands of the meal manufacturers. Such
an instance is decidedly abnormal, but as already mentioned the issue
arises to a lesser degree under conditions of ordinary trading, and,
consequently, demands a certain amount of attention.
The engineering firm specializing in plants for the exploitation of
fish-scrap, to which I have alluded, is attacking this problem in its
extensive well-equipped laboratories. The chemist favours the theory
that the extraneous salt is capable of ready removal. He also realizes
that the perfection of a simple and cheap process to this end will
probably accomplish a further beneficial purpose. Traces of blood
are occasionally encountered in the offal, and their presence tends
to discolour the resultant meal. These might possibly be eliminated
contemporaneously with the removal of the added salt.
While I have dealt somewhat at length with the artificial salt problem,
as it were, it must not be imagined that it constitutes a constant or
inseparable feature of the fish-waste by-product recovery industry:
far from it. Herring offal, while extremely varied, falls into certain
distinctive classes. There is the scrap, or waste, as well as condemned
consignments and surplus incidental to the fresh fish trade, which
during the recurring periods undoubtedly touches a very high figure.
Then there is the kippering and curer offal, the yield of which is much
more formidable and easily recoverable from accumulations at central
plants where such work is carried out upon a large scale. The kippering
refuse, of course, represents that incurred in the process of kippering
the herring and, comprising for the most part the gut of the fish,
presents a material having little body or substance.
This waste is difficult to treat except along the most modern lines.
For this reason, in pre-war days it was exploited only to a limited
degree. Yet its accumulation was enormous. At some plants the piles of
such refuse, which were to be seen, contained several hundred tons. It
failed to arouse earnest attention until the famine in oil burst upon
us during hostilities. Then these dumps created interest because it was
realized that such residue is rich in oil, enormous quantities of which
were lying dormant. Forthwith plants were erected and equipped with the
very latest types of machinery, which augurs well for the continuation
of this manifestation of industrial enterprise in the future, owing to
the great possibilities attending such reclamation.
Curer offal presents the heads and other waste portions as well as a
material quantity of broken fish. This refuse has far more body, and
so can be more readily treated to allow the valuable by-products to be
recovered.
While we undoubtedly lagged behind our competitors in turning
fish-scrap to commercial account it must not be imagined that we
completely ignored this potential source of wealth. Nevertheless, for
the most part, we were content to conduct operations along obsolete,
inefficient lines, obtaining a return far below what might have
been recorded. Had these plants been of modern design and equipment
fish-waste reclamation would have advanced by leaps and bounds during
the war period. As new machinery could not be obtained the main
task was to adapt the existing plant to satisfy the demands of the
authorities, which proved a task of distinct magnitude in itself,
because the majority of the installations in operation possessed no
striking feature other than that of being extremely wasteful from every
point of view, offering, in fact, the most convincing illustrations of
How _not_ to do it!
In some works the practice was to cook the offal in steam-jacketed
cookers. Now, when kippering offal, for instance, is being treated,
the material, owing to lack of body, tends to coagulate at a certain
stage in the process, a large volume of oil being liberated. This oil
was skimmed and the residue, resembling a stiff mud, was removed to
be wrapped in cloths for submission to extreme pressure in hydraulic
presses. This action served to express a certain proportion of the oil
remaining in the sludge. The compressed cakes were then transferred to
a steam-jacketed drier to be reduced to meal.
This process, which has not yet been completely superseded, suffers
from being involved and prolonged, although these do not constitute
the most adverse features. The greatest objections to it are the
retention of an appreciable quantity of oil in the residue, even after
subjection to pressure, which accordingly becomes associated with
the meal. The last-named being sold for fertilizing purposes, the
presence of the oil is objectionable, while the product also suffers
from being low in ammonia. Furthermore, while the sludge is being
pressed a pronounced volume of watery liquid is driven out to be lost
down the drains. Seeing that this liquid carries valuable manurial
constituents its loss is greatly to be deplored, and materially lowers
the fertilizing--and financial--value of the meal.
A variation of the foregoing process is made in other works, but it
only tends towards greater inefficiency and heavier losses. In this
case only the oil resulting from treatment of the material in the
hydraulic press is recovered! A third system involves the passage of
the pressed cakes through a continuous direct fire-heated drier. This
method is particularly objectionable, not only from the offensive
odours which are thrown off, but because the ammonia content of the
waste undergoes serious depreciation, owing to the high temperature
employed. In certain instances the herring offal is even charged into
the apparatus without any attempt having been made to separate the oil!
Such a system, as will readily be recognized, has nothing whatever to
recommend it.
It is the observance of such indifferent and unscientific methods
as the foregoing which has been responsible for the commercial
possibilities of fish-scrap to be belittled. The oil is undoubtedly
ignored intentionally because fish oils are generally held to be
worthy of inclusion only among the lowest grades of industrial oils.
Nevertheless, were a chemist to be attached to such wasteful plants
much needed reforms could be promptly introduced, although it is highly
probable that the plants would be scrapped instantly at his instigation
because of their lamentable inefficiency.
But we need labour no longer in ignorance. Modern science, as
represented by chemistry and engineering, is able to offer an equipment
capable of extracting the whole of the oil content down to 1 per cent.
In other words, 99 per cent. of the oil contained in the raw offal
and scrap can be recovered both cheaply and easily. The loss of such
a minute fraction as 1 per cent. undoubtedly represents a remarkable
chemico-mechanical achievement.
The new process completely coincides with the dictates of contemporary
science. The fundamental features are cooking the refuse under vacuum
and the ultimate extraction of the oil by the aid of a suitable solvent
such as benzine or other equally volatile spirit, or the benzine
extraction system may be used from the very beginning, in a single
and complete process. I have described this highly ingenious system
in a previous chapter together with the system of operation followed.
Obviously while the highest efficiency can only be derived from the
installation of the complete plant, the processes being interrelated,
the designer found it possible to modernize some of the old-fashioned
and wasteful equipments to a very striking degree by the introduction
of certain features to meet the exigencies of the moment.
A very convincing illustration of what can be achieved in this
connection may be related. A firm specializing in the exploitation
of herring offal desired to extend its plant, but was baulked in its
intentions owing to the various restrictions which were in force.
Accordingly it was compelled to consider the situation of how to
derive more from the existing facilities without adding to them, at
least only to an insignificant degree. At first sight this may seem
to have presented a somewhat intricate, if not actually impossible,
undertaking. Yet it was effected.
The modified arrangement introduced is decidedly interesting. The
offal is cooked in the steam-jacketed cooker, as much as possible
of the oil being skimmed from the mixture at the critical stage of
coagulation. The sediment, or mud-like residue, is then transferred
to an extractor where the remaining oil is recovered. This converts
the residue into a still stiffer substance to be finished off in the
ordinary steam-jacketed drier, instead of being completely dried in the
extractor as originally designed.
This solution has proved to be exceedingly simple and eminently
efficient. Although considerable handling is involved the extracting
capacity of the plant has been nearly doubled. The advantages to be
recorded are:--
(1) Ability to handle very much larger charges of waste when not
reducing the material to a dry meal;
(2) Reduction of the raw material to the extent of the oil removed
from the cookers;
(3) Reduction of the time required for the oil extraction by
approximately 50 per cent.
Consequently, although the adapted, or modified, process entails the
employment of extra labour, a result entirely due in this instance to
the disposition of the plant in the works, the firm in question is able
to obtain the value of the oil which would otherwise be lost, and which
more than offsets the cost of the extra labour involved.
As a result of this development a review of the whole problem
associated with the recovery of the by-products from fish-scrap was
made. Cooking plant is not so expensive as extraction equipment. The
question arose as to whether, or not, it would be possible, by the
introduction of suitable automatic handling and other labour-saving
devices, to obtain highly satisfactory results and efficiency from a
combined plant. If this could be done then it would be comparatively
easy and inexpensive to bring many of the existing recovery plants up
to date to the advantage of the firms concerned. But the factor of
capital outlay demands careful consideration, more especially in all
matters pertaining to the utilization of waste products, because costs
must be forced down to the irreducible minimum to show the necessary
return to render them attractive. The result of close investigation
of the issue led to the ultimate conclusion that the cost involved
in connection with the cookers, extraction plant, and driers, in all
probability, would be heavier than that incidental to the laying down
of a straightforward extraction plant, pure and simple, to deal with
the raw material and to turn it out as a dry product in one operation.
One admitted advantage accrues from subjecting the material to
preliminary cooking in steam-jacketed cookers. The oil thus obtained is
somewhat better in quality than that derived by recourse to the solvent.
The modified or combined process above described enables one distinct
end to be achieved. The objectionable and wasteful, as well as
expensive pressing plant can be dispensed with. It also enables the
ammonia content of the finished meal to be improved very noticeably,
as the following analyses of typical meals produced by the respective
processes prove somewhat conclusively.
PHOSPHATES. AMMONIA.
Per cent. Per cent.
Pressing process 6·5 7·5
Combined process 9·5 10·5
From the foregoing it will be seen that the enhanced yield of
phosphates and ammonia fully justifies the additional expenditure
incurred in regard to the plant and labour in connection with the
extraction process, quite apart from the main duty of the plant. This
is to extract all the oil, multiplying the usual yield many times over.
Moreover, the quality of the oil-free meal obviously is superior.
With herring offal the extraction process by benzine ensures nothing
being removed except the moisture and the oil. None of the liquor with
its valuable ammonia is lost. Consequently the whole of the nitrogenous
matter is combined with the resultant fertilizing meal.
To indicate the advantage of the benzine extraction process over the
old-fashioned method of cooking, pressing, and subsequently drying the
pressed cakes the accompanying analyses may prove informative. They
refer to herring-mixed meal produced from kippering offal and damaged
herring respectively.
BENZINE EXTRACTION PROCESS.
Per cent.
Ammonia 11·79
Tribasic phosphate of lime 9·66
Oil 1·10
OLD PROCESS.
Per cent.
Ammonia 7·5
Tribasic phosphate of lime 6·5
Oil 15·5
Both essential fertilizing constituents are lower by the second than
by the first process. This is not surprising in view of the fact that
the subjection of the sludge to pressure drives off the watery liquor
which is allowed to escape into the drains, notwithstanding that it
carries a pronounced proportion of the ammonia and phosphate. Then it
will be seen that the benzine process yields a manure carrying a less
proportion of the oil which the farmer regards with misgiving, because
the oil has been recovered for sale as such. In other words it will be
seen that, under the old process, 14.4 per cent. of oil is allowed to
pass to the land where it is not required, instead of to industry where
it is in keen request. At the prices which prevailed during the war
this represented a wastage of £7--$35--per ton of fertilizer.
Under the extraction or solvent process the meal is turned out in
a perfectly dry condition, either for use as a poultry food or
fertilizer, the recovery of the oil and drying being completed in the
one operation. The method is not only the acme of simplicity but it
assures the maximum yield of oil, only 1 per cent. being lost. It is
also rapid, it being possible to treat a charge of 8 tons of offal in
10 to 12 hours in one unit.
White fish and general offal do not contain sufficient oil to warrant
the expense of solvent extraction. If it should be desired to secure 99
per cent. of the slight proportion the offal carries then submission to
the benzine process is imperative, for the simple reason that it cannot
possibly be recovered in any other way. The modern system of drying
such offal is by steam heat under vacuum or reduced pressure.
This process, to which I have also devoted adequate attention
previously, not only enables a product of high quality to be obtained,
enabling it to command an enhanced price in the market, but it also
conduces towards the retention of the nitrogenous contents of the meal.
From the fertilizing point of view this is the main end to be achieved.
Colour of the meal is another factor which demands recognition. It
plays a far more prominent part in the commercial value of the product
than might possibly be conceived. The American drying system, operating
along direct fire-heated lines, while efficient so far as it goes,
namely, the elimination of the moisture, yields a darker coloured meal,
owing to the high temperature which has to be used, while, of course,
the nitrogen content is lowered by such practice.
The vacuum system has also proved highly efficient for the production
of cod-liver oil. The temperature of rendering being low gives an oil
of superior colour and odour, two factors of vital importance when
the oil is being extracted for medicinal purposes. This is a somewhat
delicate product to manufacture, especially when the livers are in a
state of partial decomposition, because in this instance colour and
sweet taste are particularly vital and difficult to assure.
I have referred to the circumstance that fish oils commercially rule
low in the scale of industrial oils. But even fish oils possess one
feature common to the highest grades of oils. They carry a certain
proportion of glycerine. During the war the oil extracted from
fish-scrap and offal was subjected to further treatment to swell our
domestic supplies of this indispensable commodity. Even under normal
conditions the reclamation of oil from fish waste to secure this
glycerine offers further inducement to this phase of industry, and is
also capable of considerable development.
Fish oils are also destined to play a more prominent part upon the
table than has been the case heretofore. Their inherent fluidity
and refusal to solidify, except at low temperatures, have hitherto
reacted against their use in this direction. But the increasing demand
for margarine as a substitute for butter, and the discovery of the
hydrogenating process for eliminating the two outstanding defects, have
invested the future for fish oils with additional significance, more
especially as by the hardening process, as it is called, the pungent
taste and aroma so distinctively of the sea and its inhabitants are
removed. By virtue of this discovery fish oils are entering more and
more extensively into the manufacture of margarine. The circumstance
that they yield a product so closely allied to the genuine article
from the dairy as to be difficult of detection, except by elaborate
investigation and specialized methods, has served to accentuate this
tendency.
We must derive far-reaching benefits from the utilization of our
fish waste of every description--not only the offal arising from the
preparation of the foodstuff for the table either in a fresh, kippered,
cured, or canned condition, but the inedible contributions from the
trawls. Those members of the sea’s vast and varied population, such
as the whale, which are trapped for certain highly-prized portions of
their bodies, must be fully exploited. For decades the whale fishery
has been conducted along the most wickedly wasteful lines for which we
are paying to-day. The Scandinavian whalers have been among the worst
offenders in this respect, but they are now being compelled to turn
from the folly of their ways and are endeavouring to utilize the whole
of the carcases of their prizes.
So far as the average member of the community in these islands is
concerned it is a moot point whether he, or she, has any tangible
idea of the magnitude of the British sea-fishing industry. From the
abundance and cheapness of the food a vague notion obtains that it
must certainly be somewhat impressive. To obtain a graphic idea of its
enormous proportions we must venture beyond the limits of domestic
consumption and see how we help to feed the foreigner. Under normal
conditions we ship approximately 1,250,000,000 lb. of fish every year,
representing in value a round £7,750,000--$38,750,000. Of this huge
total the humble herring represents nearly 1,120,000,000 lb., valued
at approximately £6,000,000--$30,000,000. Of the total herring catch
about one thousand million--1,000,000,000--lb. are subjected to curing
or salting for the foreign markets, the value of those exports being
£5,350,000--$26,750,000--so that the herring may truly be said to form
the backbone of the British sea-fisheries. In these circumstances, and
bearing in mind the huge quantities handled, the item of waste must
necessarily loom heavy. It cannot be avoided. Therefore it behoves
us to turn our harvest from the sea to the utmost advantage and to
eliminate the item “loss” from our operations.
As the by-products from fish-waste become appreciated we may even
proceed to the lengths pursued along the northern Atlantic seaboard of
the United States. There the harvest of the menhaden, a fish totally
unfit for human consumption, is carried out expressly for the oil
obtainable therefrom. It has become a flourishing trade--one which is
steadily expanding--special vessels being engaged in the fishery. While
it is questionable if much fish of a comparative character and totally
unsuited to the table is to be caught in the waters around our coasts,
Farther Britain can point to a different state of things. Our Dominions
should find it profitable to emulate the American example and exploit
adjacent waters essentially for inedible fish to extract the oil and
to convert the residue either into fertilizer or poultry food. There is
a lucrative and developing market for all three commodities.
But the problem of to-day, in so far as it particularly affects Great
Britain, is to solve the issue incidental to the glut catches, so as
to prevent the wasteful distribution of the raw fish over the land as
the easiest way out of a perplexing dilemma. If we can divert such
unwanted hauls from the sea to reclamation factories, confident in the
knowledge that there they will be worked up to their utmost in the
interests of commerce, we shall be able to record an industrial and
economic achievement of incalculable consequence to ourselves. To dump
newly-caught fish upon the land merely because it cannot be absorbed
by the community as a foodstuff constitutes one of the most deplorably
wasteful, if not actually criminally extravagant, charges ever levelled
against contemporary civilization.