In dealing with the sewage question during the last century, it will
be an advantage to distinguish between the theory and practice of
sewage purification, as such a division of the subject will render it
less complicated and will tend to avoid misconceptions.
Dealing first with the theoretical side of the question, it is very
doubtful whether at the dawn of the century even a working hypothesis
existed to explain the process of sewage irrigation which was then
adopted in one or two instances, notably at Edinburgh, where the town
sewage was very successfully purified on the Craigentinny meadows. It
is more than likely, that at this time instinct took the place of
theory, and that sewage irrigation was an instinctive imitation of
irrigation with river water employed for many centuries in some
eastern countries.
Later on it is on record, that Cagniard de la Tour in France, about
the year 1825, and Schwann in Germany, about the year 1836, expressed
the view, that organised substances—micro-organisms—played some role
in fermentative and putrefactive changes. Almost diametrically opposed
to this were the views authoritatively laid down by the then star in
the chemical horizon, Justus von Liebig, who, about the year 1845,
maintained that these changes were brought about by the dead inert
matter itself—by molecular movements in the same—and not by organised
substances, the presence of which in fermenting or putrefying
substances was purely accidental. So great was Liebig’s authority
then, that many almost blindly adopted his views, and the strife that
commenced around these opposing views was fought with the greatest
bitterness. But the stronghold of old ideas, which were gradually but
surely being supplanted by new ones, could not hold out for ever
against combined attacks, however stoutly it was defended by its
designer, and its final downfall came about the year 1860, when a
young Frenchman, Pasteur, established beyond doubt by his ever
classical researches, that fermentation and putrefaction were, in the
first instance, due to living organisms and not to dead matter.
Pasteur further demonstrated that living organisms were also the cause
of some and probably of all zymotic diseases.
So far, so good! But unfortunately the methods of biological research
employed by M. Pasteur were very cumbersome and left otherwise much to
be desired, so that his discoveries could not be fully utilised and
extended, until in 1882 Robert Koch of Berlin published his new
methods of investigation. This was the signal of raising the
floodgates of biological (bacteriological) research throughout the
world with this result, that the flood waters pent up until then
inundated practically other branches of scientific investigation and
drowned their individual life for some time to come.
During this interval, 1860 to 1882, investigators who wished to study
the organised impurities in sewage had to proceed by indirect methods.
They had no means of ascertaining by direct biological experiment the
number and character of the micro-organisms contained in sewage: all
they could do, was to determine chemically the dangerous nature of the
sewage by the amount and origin of organic matter it contained, which
would probably act as food to the germs; and the greater this amount
was, so it was inferred, the greater would be the number of germs it
harboured and the more dangerous its character.
This was the condition of things at the time the second Rivers
Pollution Commission carried out its investigations, which in many
respects, and rightly too, are still considered standard
investigations. It cannot be surprising, therefore, that, being
without proper means of biological examination, and having to rely
chiefly on chemical methods only, the Commissioners came to the
conclusion that the changes brought about in sewage purification were
due to mechanical and chemical agencies!
It is frequently a matter of the utmost difficulty to ascribe, after
the lapse of half-a-century, a new theory to one special author, as
several investigators may have been trending the same way quite
independently of each other, but may not have been equally successful
in the matter of their publications becoming generally known.
Theories, as a rule, do not drop out of the clouds like meteorites,
they force themselves gradually upon men’s minds and are elaborated by
them until ripe.
Bearing this in mind, and subject to further research, it would appear
as if Alexander Müller had been the first to apply Pasteur’s general
theories as to decomposition, fermentation and putrefaction to the
problem of the self-purification of sewage. He made his experiments in
1869 and published them in 1873. Since that date a very large number
of investigators have been at work on similar lines, and whilst it
would lead too far to deal with them minutely, it ought to be stated
that the results of their labour confirmed the view of living
organisms playing a very important part in the decomposition of
sewage. Among the many names prominent in this respect are those of
Schloesing, Müntz, Hatton, Warrington, Sorby, Winogradsky, Percy
Frankland, Dupré, Emich and Dibdin. That set of researches, however,
which has done more than any other to consolidate the theory of
bio-chemical changes taking place in the self-purification of sewage
are the investigations of the Massachusetts State Board of Health,
which were commenced in November 1887, and are still being continued.
Since 1895 a large number of additional experiments have been made,
which will be dealt with more in detail later on, but speaking
generally they have not materially increased our knowledge of the
processes taking place in sewage purification.
Summarising the remarks on the theoretical aspect of this question,
it may be said that, as to the agencies at work, we know now they are
of a mechanical, chemical and biological nature; but as to the
processes and products brought about by these agencies we know very
little beyond the initial and terminal stages, as will be pointed out
in some of the subsequent observations.
Directing now attention to the practical side of the question, it has
already been stated that the only known sewage treatment at the
commencement of last century was land irrigation. Then about the
middle of the century chemistry seems to have taken the matter in hand
and tried to make a lucrative business out of it. It is on record,
however, that it did not succeed in this attempt, and the financial
loss which this endeavour has caused is a dismal subject to
investigate.
There is before my mind’s eye the case of a gallant officer of His
Majesty’s land forces who, after having reached very near the summit
of his career, retired and employed his time in trying to make a
fortune out of sewage. So enamoured was he of the subject, that—so the
story goes—he commuted his pension to have all the more ready money;
but fortune did not smile on him, and his last days were spent under
the lengthening shadows of the sorrow of financial difficulties,
having practically lost all he possessed.
The emphatic verdict of the first Sewage Commission of 1857, the first
and second Rivers Pollution Commission, and, indeed, of all other
authoritative investigations, was in favour of land treatment; and it
cannot, therefore, be surprising to find that the Local Government
Board insisted, save in exceptional cases, that “any scheme of sewage
disposal, for which money is to be borrowed with their sanction,
should provide for the application of the sewage or effluent to an
adequate area of suitable land before it is discharged into a stream.”
Indeed, had this body taken any different view and neglected the
findings of practically all authoritative inquiries, it would have
been singularly deficient in the discharge of its duties to the
ratepayers of this country.
But the best of land cannot go on for ever doing its duty if by
systematic neglect and ignorance the essential conditions for
successful purification are year after year violated; and the great
pity is that the Local Government Board, after deciding in favour of
land treatment, did not systematically superintend this operation. It
may not have had the power, but it is quite evident that had it done
so, things would not have drifted from bad to worse, until local
authorities, driven to despair by the apparent failure of land and not
discerning the right cause, refused altogether to be ruled by what
seemed to them a very unfair and absurd restriction.
It was at this time that Mr. Dibdin, who, on behalf of the London
County Council, had been carrying out a set of valuable experiments,
came forward with his application of well known theories to sewage
operations on a large scale. As I pointed out at the time, Mr.
Dibdin’s experiments proved beyond a doubt that the application of
sewage to suitable land was right in principle and that the failures
were brought about by the non-observance of the rules laid down by
this gentleman—that, in fact, sewage irrigation was the only natural
method of sewage purification and that all the other methods were
artificial. I described land treatment as the natural self-purification
of sewage and the oxidation or contact bed system as the artificial
self-purification of sewage.
But the swift current of public opinion had set very strongly against
sewage farms, and nothing but the contact bed treatment would do. A
large number of experimental plants on this system grew up like
mushrooms all over the country, and the waves of enthusiasm seemed at
one time to engulf even the Local Government Board itself with its
“antiquated notions,” until Parliament came to the rescue and
appointed on May 7, 1898, a new Royal Commission to study the question
of sewage purification.
This Commission consists of nine members,[4] i.e. six professional men
and three laymen. Of the professional men, one is a biologist, one a
chemist, two are medical men in administrative positions, and two are
engineers likewise in administrative positions. Of the laymen two are
members of special boards for the prevention of the pollution of
rivers.
So far the Commissioners have issued an Interim Report dated July 12,
1901, a volume of evidence and a volume of appendices. Quite lately,
it is stated, they have issued a further Interim Report, to which are
attached separate reports on some special subjects by their officers,
but this report has not yet come to hand.[5]
At the time of their first Interim Report, July 12, 1901, the
Commissioners had held altogether thirty-five sittings, the first of
which was on June 22, 1898, and the last on May 22, 1901. The period
thus covered is nearly two years, and out of the thirty-five sittings
thirty took place in London, and five in the provinces, viz. at Leeds,
Ripon, Manchester, Accrington and Reigate.
On these occasions, all in all, fifty-eight witnesses were examined,
who may be grouped as follows:
1 Zoologist
1 Botanist
2 Laymen
3 Bacteriologists
5 Lawyers
7 Medical men
11 Patentees
14 Chemists
14 Engineers