Autobiography of William Joseph Dibdin F.I.C.,
Section 3 Chapter 2
River and Sewage Work and the Purification of the Thames 1884-1897
In consequence of the exceptional hot and dry weather in the early summer of 1884, the condition of the River Thames in the neighbourhood of the sewage outfalls at Barking Creek and Crossness became distinctly unsatisfactory, and I was instructed by the Board to report upon the cost of deodorising the whole of the London Sewage with the result that an order was placed in my order book instructing me to at once undertake the deodorisation at a cost not exceeding £6000 a week! I had only a day or two to make my reports and had to assume that a suitable deodorant could be obtained in sufficient quantity at the then market prices. To add to my perplexity Sir Joseph Bazalgette ask me to commence operations the same day the order was given ! How was it possible to get any reasonable quantity of any material to the outfalls with such a speed ? But the necessity of doing something at once, even if only to allay public feeling was urgent. The only available material was Chloride of Lime; I could not get an offer of more that a few hundred weights of Permanganate of Potash even at £80 per ton. To show the magnitude of the proposition let it be remembered that the volume of sewage was then computed 156,000,000 gallons per 24 hours, exclusive of storm water. To provide only one grain
[ per gallon of sewage – 1 grain is about 64 milligrams ] of any deodorant for this quantity meant the daily supply of ten tons of material or 70 tons per week. My experience with the River had clearly shown that the satisfactory disposal of the sewage had formerly been brought about entirely through the feeding properties of the living organisms abounding in the water containing sufficient quantity of oxygen dissolved from the atmosphere. This was confirmed by the researches of Prof. Odling, Dr Dupre, Dr Sorley and I accordingly looked for some material that would deodorise with out killing, but absolutely nothing of the kind then could be obtained and the only alternative for the moment was to use chloride of lime in order that something should be done. I according approached the chemical agents and found that in view of the demand for deodorants and disinfectants there was little to be obtained and that at only 50% higher than the usual contract price of £8.10.0 per ton. Then the fun began. I flatly refused to commit the Board to these extortionate prices and declared that I would make chlorine in the works and treat the sewage with it directly instead of buying chloride of lime. This startled the trade and one agent after another called and made offers of special parcels of one hundred or two hundred tons at about £10 per ton as a great secret and favour. Very soon I got sufficient sent to the works and commenced treating the sewage. As I anticipated, however, it soon became evident that the use of such quantities of chloride of lime as we could obtain while making a momentary difference, was totally inadequate especially in view of the fact that after the immediate disinfecting action had ceased the condition of the water was such as to develop an even worse odour. This was because the chlorine was killing such living organisms as were in the river and their dead bodies were only increasing the general mass of corruption. In view of the objections to the continues use of chloride of lime I had already started on the war-path to find an alternative and the joke went round the laboratory that Mr Dibdin had £6000 per week to spend on chemicals and the first thing he did was to buy a sixpenny frying pan ! Exactly true – the frying pan was at once set to work to demonstrate the facility with which we could make manganate of soda ! We then put up a series of furnaces at the Crossness Outfall works, Mr Houghton, the Superintendent and his son Frank, throw themselves heartily into the work and backing up my chemical efforts with their engineering skill in the most whole- hearted manner.
Before long we had a ship-load of oxide of manganese from the Baltic alongside the wharf and barge loads of caustic soda. Great iron pans about 8 feet in diameter were mounted on furnaces ranged round the main furnace shaft which was thus used for the flue and in the following winter of 1884-85, we were making large stocks of manganate of soda in reserve for use in the summer.
The effect was that when the manganate of soda was dissolved and treated with sulphuric acid which we stored in huge lead tanks, the well known permanganate was formed. The effect of our operations was to enable us to obtain practically unlimited quantities of a suitable oxidising deodorant at about £8 per ton, against £40, the lowest price for which I could then obtain only a practically useless quantity. The action of the permanganate solution was to completely deodorise the sewage and supplying chemically active oxygen without injuring the living organisms in the river and the use of chloride of lime was completely avoided.
The result of this work was such that in the following summer of 1885 we took time by the forelock and the river was kept in fairly good condition at a cost far below the original estimate.
These operations were continued during the years 1885-86 at an expense of less that one half the contemplated sum then considered necessary for permanent works for dealing with the sewage, it being remembered that these deodorising operations were only tentative pending the construction of necessary plant whatever that might be decided to be. However before the summer of 1887 arrived doubt was thrown on the wisdom of my action in using permanganate by Mr Rider Cook, the member of the Board for Popular, and in order to make certain Sir Henry Roscoe was asked to report. I always consider that this course was forced on the Board in the interests of the chloride of lime manufacturers who were saddened at the loss of orders for chloride of lime. However Sir Henry commenced by using chloride of lime, a £10,000 order being given for that material.
When Sir Henry was appointed, Lord Mapheranome, the chairman of the Board suggested that I should call upon him with a view to friendly relations in regard to the Board’s action. This I did and took the opportunity of pointing out to Sir Henry why I preferred the permanganate telling him that the problem was more a biological than a chemical one, as under no circumstances must we kill off the living organisms. It has always been a matter of profound regret to me that my reception was something more than cold and the friendly advance I had made, at the kindly suggestion of our chairman, was treated in a manner totally different from that which I had a right to expect.
However the summer arrived and deodorising operations with chloride of lime commenced, the workmen who had hitherto been employed being superseded by men specially sent from the manufacturers works! All concerned were treated with neither more nor less than a supercilious scorn but little concealed. It was really wonderful. But the end came on one very hot July day. I was making an inspection of the river in a small launch accompanied by Mr Baker, Sir Henry Roscoe’s chief Assistant. We were rounding Silvertown Point and the launch was churning up filthy black mud in equally black water and the combined and peculiar stench of mixed chloride of lime and sewage sludge was equally evident.
I am an old chess player and like to move quietly and with effect when possible. I quietly remarked to Baker "By Jove it is bad today !" He replied "Yes it is " I then said I really do not think it could be worse" to which he replied "No, I don’t think it can". There I had him and speaking warmly I said "You admit it cannot be worse, then why do you go on wasting the ratepayers money by using chloride of lime? Don’t you think it would be better to go back to Sir Henry and advise him to try permanganate again? I have plenty in stock and can get it to work again at once. We have been ready all along".
Baker was so struck with the force of the facts that he at once saw Sir Henry who consented to stop the chloride of lime and to use permanganate. I think it was the next day he went down to Barking Creek with me and witnessed the effect of treating the sewage with permanganate. I told him I could turn the sewage with a solution of permanganate and use it to deodorise the river if necessary and he agreed to an experiment which we tried then and there of adding less than 40 grains of manganate plus sulphuric acid per gallon and turning the sewage into a red stream which on meeting the river turned the black to brown.
As a result the chloride of lime was given up and the permanganate used. When Sir Henry made his report he said "I find the permanganate preferable" and not that he confirmed my action in using it, thus trying to take all the credit to himself and I have been once told how clever it was of Sir Henry to use permanganate for treating the London sewage !
One of the side issues in this connection was the use I made of the permanganate to deodorise the sewage in the sewers, before it arrived at the Outfalls. This arose from two causes. First complaints made from the smell from the sewers and second the necessity if doing something to mitigate the effects of the discharge with the river in London of large quantities of sewage at storm periods from the storm outflows. As it was clear that the use of permanganate under the prevailing conditions was distinct I agreed that we might as well put some of it into the sewers as they passed through London. To this the Board agreed and some twenty stations were arranged from which the permanganate was added to the sewage day and night, with marked effect. Of course these were only temporary measures and unnecessary when the new works and pumping stations were completed.
In 1890 when the river was in a very bad condition during the summer months, one of the sludge boats was loaded with 1000 tons of a strong solution of manganate of soda and sulphuric acid, making the red permanganate solution and this was discharged into the river as the vessel slowly steamed up towards Woolwich – the effect being to turn the black water into brown. This was a drastic remedy, but it had a marked and good effect. I remember the Harbour Master coming on board to know what we were doing!