The E.B. Eddy Digester Tower is a five-storey stone masonry structure 32m tall and 10m by 13m in plan, which was constructed approximately 100 years ago. The tower contains a large digester tank, which extends from the ground to the fourth floor level. Between the fourth and fifth floors, there is a large wooden hopper, which is supported on structural steel framing
The Digester Tower is comprised of stone masonry load bearing walls and reinforced concrete slabs at floor levels 2 through 4. The fifth floor and the roof are of timber construction.
The old E. B. Eddy stone digester tower is of historical importance in several respects. It exemplifies the beginnings of an important industrial activity not only in the local and regional economy of the Ottawa Valley, but nationwide. In fact, for half a century, from the 1920s to the 1970s, the pulp and paper industry dominated the entire industrial sector of the Canadian economy, and the digester was a key element in this type of production. The E. B. Eddy tower was the first vertical digester, a model that would rapidly supplant the horizontal digester.
Ezra Butler Eddy, an American entrepreneur who moved to Hull in 1854, was already interested in the production of cellulose before 1878, when he obtained a patent to produce pulp. This product was used to make indurated fibreware articles, such as kettles and washboards. In 1883, Eddy rented from Hannah Wright land and buildings on the site of Wright, Batson & Currier, which had been closed since 1878. In 1888, always on the alert for new ways to increase the profitability of his company, Eddy began producing paper pulp, which he sold in the United States, and manufacturing paper. He purchased the property that he had been renting and erected new buildings on this site and near the Chaudière Falls.
In 1888, one year after Charles Riordon became the first Canadian manufacturer of sulfite pulp, Eddy built a factory using this process. With its four horizontal digesters, it went into operation in December 1889. The old landing structures that Eddy took over from Wright, Batson & Currier became part of the operation. The former stone storehouse continued to house the steam boilers. A brick floor was laid in the old hotel so that sulphite boilers could be installed; the rest of the building was used for storing the sulphide and other acids and oil. The former stable became a shed for vehicles.
Once he had become a master of pulp production, Eddy did not rest on his laurels. His company entered the twentieth century as a major producer of paper in Canada. But the Great Fire of April 26, 1900 burned nearly all of the company's installations to ashes. Only the sulfite plant survived. During the reconstruction, the company engineers perfected a new digester that would improve the production of sulfite pulp.
The type of horizontal digester installed in the late 1880s had been developed in 1874 by the Austrian Alexandre Mitscherlich, perfected, and marketed for the first time in the United States in 1882. It produced pulp relatively cheaply by chemically dissolving the lignin in the wood to liberate the cellulose. Tree trunks were reduced to chips, and introduced into the digester - a sort of pressure cooker. Under high pressure, the chips were heated in steam before being soaked in sulphite and cooked again for several hours. The end result was a kind of paste called "pulp". This process left room for improvement: The chips had to be shovelled into the digester, and the pulp had to be shovelled out. Furthermore, the quality was inconsistent because the acid did not penetrate the shavings evenly. Finally, it was a slow process, taking about 30 hours to produce the pulp.
To remedy these problems, the Company engineers designed a completely automated vertical digester in 1901: a square stone tower about 9 metres wide by 34 metres high. The digester itself, enclosed in stone and a layer of fireproof bricks, was 14 metres by 5 metres. Above the digester, a large funnel received wood chips transported on a conveyor belt. The fact that this digester remained in operation until the demolition of the plant in 1972 is eloquent testimony to its efficiency. The four horizontal digesters were abandoned in 1924 and replaced by two other vertical digesters, further attesting to the superiority of this installation.
Plaque reads; Once part of a sulphite mill that began operation in 1888, the Digester Tower was part of a revolutionary chemical pulp technology invented by George Millan, an associate of the E.B. Eddy company.
Furthermore, to the best of our knowledge, this tower is the last one of its kind still standing in the country. (see link below).