From privy to full treatment – A history of sewage treatment in Ontario (Ann Marshall, 1982)

Ann Marshall
Environment Ontario Legacy, Vol. 11, No. 1 July 1982. Pg. 28

Once upon a time, when about 220,000 Indians lived in this vast country stretching from the Atlantic to the Pacific, the human wastes produced by the roving tribes were easily absorbed by nature. The environment was left unspoiled and Ontario’s waters clear.

The first settlers in Canada and in Ontario were farmers. They also had few problems with the disposal of sewage.

The situation changed when towns and cities started to grow at the turn of the century.

During the 19th century, medical science had become aware of bacteria as the cause of diseases and of the connection existing between the disposal of sewage and the spread of diseases caused by waterborne bacteria, such as typhoid fever.

This awareness and the frequent incidence of typhoid fever in Ontario communities provided the first impetus for measures that would protect man and the environment and, eventually, for the development of sewage and water treatment systems.

In the 20th century, the typhoid problem was solved, but the continuing rapid growth of large centres of population and the spread of industrialization during and after World War 1 and, especially. World War II, created new pollution problems and presented new challenges.

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In the late 1800s most localities took drinking water from wells and disposed of slops and waste in privies. These privies were emptied from time to time and their contents, “night soil”, were used as manure or left to decompose in more or less suitable places. Cesspools or septic tanks, in which waste could decompose by the action of bacteria, were used rarely.

In large communities, properly constructed and connected sewers were considered to be the best means for the disposal of sewage, but municipalities did not always use the system best suited to their circumstances. Drains and sewers were often improperly built; closets and cesspools were connected to drains unfit to receive and to carry away the contents.

Drains opened into houses and sewage gases were not properly ventilated. Many sewers were not laid to proper grade and had to be flushed. Many sewers were, in fact, underground cesspools.

In the water-carriage sewer system, generally established in densely populated areas, sewers were laid at a proper grade to allow quick passage of waste. A sufficient amount of water had to be provided to carry the waste to the sewer outfall. Effluents were generally discharged into water courses, and the only treatment generally used was simple dilution. Other treatment methods were known at the time, but were rarely used in Ontario because they were either of dubious effectiveness or too costly.

In 1896 a chemical purification treatment system was tried for the first time in Hamilton, but was soon abandoned.

In 1882 the Provincial Health Board was formed in Ontario to advise local health boards. One of the major concerns of the board was typhoid fever. Eighteen persons out of 1,000 suffered from typhoid or similar diseases, and the average mortality rate was much higher than the one statistics registered in European cities.

To institute some means of control, the board gathered information from the United States and from Britain. Britain was. at the time, the leader in the development of sewage disposal methods.

The experiences gained in Europe showed that treatment of municipal water supplies and treatment of sewage wastes could reduce the incidence of typhoid fever. In Frankfurt, Germany, the death rate of typhoid was 8.5 per 10,000 inhabitants in 1856. On completion of a good sewage system, the death rate dropped to 2 per 10,000 inhabitants.

In Ontario, sewage treatment consisted mainly of a dilution of the effluent from the outflow pipes. Aerobic bacteria were expected to decompose the organic matter in the sewage as it travelled downstream.

Unfortunately, sewage outfalls often emptied into the same body of water from which drinking water was taken. In Sarnia, for example, sewage outfall and drinking water intake were only 150 feet apart.

In Toronto the first sewer system was built in 1840, and its content was discharged untreated into Ashbridge’s Bay. The bay became unsightly and a danger to public health. The solution applied to such a problem at the time was to move the sewage outfall elsewhere.

From 1880 on, sewage systems were built to a greater extent in the large communities. By 1891, they consisted generally of small-gauge sewers that excluded all storm and rainwater. They were constructed to be easily inspected and cleaned.

strong opposition from municipalities

Although this system carried a concentrated form of sewage it was considered at the time to be the most sanitary and economical. The main problem of sewage disposal was what to do with the effluent from the sewer.

By 1901 Ontario’s population had grown to 2.2 million. Sewage treatment had become more important than ever before, but its introduction ran into strong opposition. Municipalities situated on the shores of the Great Lakes balked at the costs they were expected to incur and refused to treat their sewage until communities on the U.S. shores decided to treat their own.

During the first decades of this century a number of sewage treatment methods were available to municipalities;
— Imhoff tanks and filters were used to a minor degree.
— One fine-screening plant was used in Sudbury for a short time but proved to be not very effective.

sprinkling filters – first bio-treatment

— Sedimentation tanks were popular. They are still generally used today as primary treatment.
— Septic tanks, and a combination of septic tanks with other forms of treatment such as sprinkling filters, were popular. Sprinkling filters, also called percolation systems, were the first biological treatment systems used extensively in Ontario. One of the first ones was installed in Stratford.

Other plants of this type were built in Brampton in 1906, in Guelph in 1909 and in New Toronto in 1913.

activated sludge duplicates nature

In Stratford, sewage was first passed through screening chambers and a liquifying tank. It was then sprinkled through filters over a bed of crushed rock . The stones were coated with slime which consisted of bacteria which fed on the organic matter in the sewage.

Sprinkling filters were gradually replaced with activated sludge plants which have a greater treatment capacity. They can remove up to 95 per cent of the contaminants against an 80 per cent removal in sprinkling filters.

The activated sludge system duplicates and accelerates nature’s waste treatment process. In it air is entrained into the sewage flow. The oxygen content of the entrained air provides a good environment for aerobic bacteria and enhances their ability to decompose sewage.

True activated sludge plants did not come into use in Ontario until, the mid-’20s.

In 1928 Ontario experienced more building activity than in any year since 1913. By 1929 there were 95 municipal sewage systems in operation in Ontario, serving 1,800,000 people. Forty-six systems were equipped with treatment plants: 16 of these plants used sedimentation tanks, nine Imhoff tanks and filters and 19 were activated sludge plants. Plant effluent was not chlorinated.

typus control by chlorination

From 1903 to 1913 the typhoid death rate was 24.4 per 100,000 people in Ontario. In Europe the rate was considerably lower at 8/100,000.

Typhoid was scattered throughout the province. Ottawa suffered two major outbreaks between 1910 and 1913. One in 10 persons that contracted the fever died.

To stop the spread of the virulent disease, the Ontario Board of Health was given the responsibility to approve all sewers and watermains.

Dr. Albert E. Berry, who joined the Board of Health in 1920, recognized that the incidence of typhoid could only be controlled by the introduction of chlorination of effluent and of water, and by the pasteurization of milk. As director of the division of sanitary engineering, Dr Berry worked diligently from 1926 on to promote the use of chlorine. He was also responsible for the introduction of the compulsory pasteurization of milk.

By his initiative, Ontario became one of the first jurisdictions in the world to apply chlorination and pasteurization against much resistance, mainly from dairies which feared an alteration of the taste of milk by the process.

To gather firsthand information, then Ontario Premier Mitchel Hepburn toured the typhoid ward of the Hospital for Sick Children in Toronto. One visit was enough to persuade him of the need of compulsory pasteurization. Dr. Berry was given the assignment to provide the suitable legislation and to enforce it.

An important tool in the battle against typhoid fever was the development of the biochemical oxygen demand (BOD) test in the 1920s.

excessive oxygen demand by industrial waste

Another important step in the control of pollution of Ontario waters was the formation of the International Joint Commission in January, 1909, by an agreement between Canada and the U.S. In the agreement, both countries promised to co-operate to protect their boundary water, principally the Great Lakes, from pollution.

The first major action of the new commission was the completion of a study designed to determine the extent of pollution in boundary waters. As pollution indicator, the incidence of coliform bacteria was used.

The study , completed in 1912, showed that the water in certain areas of the Great Lakes was dangerously polluted, and that all municipal water supplies taken from the Great Lakes were unsafe if the water was not treated. In the few municipalities that supplied treated water, the treatment was minimal.

Every municipality on the shores of the Great Lakes discharged untreated sewage into the lakes, and the typhoid rate in these municipalities was the highest in Ontario and in the U.S.

The report of the IJC recommended a daily bacteriological examination of drinking water, the treatment of all water supplies and the installation of proper sewage treatment.

After a good start in the 20s, the construction of sewage treatment systems decreased in the years 1930 to 1955.

recommended treatment: sedimentation, disinfection

During the depression years the limited funds available to municipalities were generally used to alleviate social problems.

The depression years were followed by World War II which imposed a different set of priorities together with the lack of materials and manpower for non-military uses.

The war years were followed by the postwar slump, which lasted till about 1955. In this time materials were still scarce and an escalation of prices prevented municipalities from building new sewage treatment facilities or from improving the old ones, strained as they were by the growth of population in large centres and the development of industries.

As the growth of cities and of industrial development continued, sewage purification works were overloaded not only by sewage inflow but also by liquid industrial wastes dumped into the system.

To support municipal sewage and water treatment projects, the Municipal Act, as amended in 1943. allowed municipalities to finance such projects by a user rate rather than from taxes. In 1950 the Municipal Improvement Corporation was established to help municipalities to borrow money for sanitary works at low interest rates.

Despite all the difficulties, some progress was made. At the end of 1930, 25 of 70 sewage disposal plants provided activated sludge treatment. By 1936, although dilution was still the most frequent used method, 26 plants had activated sludge treatment, nine had sprinkling filters, 33 sedimentation tanks and two had fine screening facilities.

In 1943 , 70 per cent of the population of cities enjoyed sewage treatment. In 1955, 10 new sewage treatment plants were put into operation, for a total of 54 activated sludge, 19 sprinkling filters and 129 primary treatment (principally sedimentation) plants.

By 1950 the typhoid death rate had decreased to 0.02 per 100,000.

From 1946 to 1949 the IJC conducted another study of Great Lakes water quality. At the time, 96 percent of the population of the area had sewers and 86 per cent had primary treatment of wastes. Only a small percentage of communities were served by secondary or activated sludge treatment. Despite the increased number of plants providing primary treatment, the concentration of bacteria in some of the Great Lakes waters was three to four times greater than the concentrations detected in 1912.

control of pollution in the Great Lakes

At the time of the 1912 study , industrial wastes were of little concern. During the following decades, however, industry spread tremendously. At the time of the 1946-1949 study, the oxygen demand of industrial wastes was equal to the BOD of the untreated sanitary wastes that could be expected from a population of 4 million people.

In fact , industrial wastes placed a greater demand on the receiving waters than the combined total sewage produced by the study area population of 3.5 million.

The study recommended the treatment of all municipal wastes by sedimentation and disinfection, the introduction of more efficient secondary sewage treatment and the treatment of industrial waste.

In 1956 Ontario established its Ontario Water Resources Commission as the first organization of its type in the world. The commission’s mandate was to build, finance and operate sewage disposal and water treatment facilities in the province.

There were many reasons for the establishment of the OWRC.

Until World War II, water was taken for granted in Ontario. The war, industrial boom, increase in population, and increase in capital costs and interest rates made it difficult for municipalities to meet a suddenly increased demand for services. In some areas water was in short supply. Increased pollution required costly additional treatment.

Practically all municipalities were required to build secondary treatment works unless situated on large bodies of water. In the mid-1950s. Ontario’s water situation was deplorable and some authority was needed to bring order to the situation.

It was Premier Leslie Frost who was directly responsible for setting up the OWRC. At an informal gathering in 1953, President Dwight Eisenhower of the U.S. challenged him, “Mr. Frost, you people here have a great country with great possibilities so don’t let them ruin your water . . . You really should remember that pure water is one of your greatest assets. But when you’ve got it, you don’t think about it.”

This statement provided the impetus to Mr. Frost to form the OWRC.

Following the passage of Bill 98, a ruling body of five members of the commission was appointed: A.M. Snider, J. A. Vance, W.D. Conklin, R. Simpson and W.H.C. Brien. At the first meeting, on May 17, 1956, Dr. Berry, ‘one of the foremost authorities in North America, probably in the world” was appointed general manager and chief engineer. Brian Larmour was appointed secretary.

The former Act of 1956 was replaced by the Ontario Water Resources Commission Act, 1957. It came into effect on April 3, 1957.

During the OWRC’s years of service, much progress was made and many sewage treatment facilities were constructed. By 1961 , 277 sewage treatment plants were in operation in Ontario. The commission expanded in size and responsibility: regional offices were opened; training courses for sewage and waterworks plant operators were initiated; and ‘Great Lakes studies were gradually undertaken for the commission’s own use rather than for IJC only.

OWRC develops financial aid to towns

The OWRC’s first major project was to change Stratford’s sprinkling filter to an activated sludge system, and to add sludge digestion. Stratford was forced to do this because adjacent townships had complained that the river was so polluted and devoid of oxygen that it was as black as tar. The plant started operation in 1958.

More financial aids were developed. In 1960, the federal government agreed to assist municipalities by financing two-thirds of the costs of certain portions of sewage treatment works. The funds were administered by Central Mortgage and Housing Corporation.

The commission agreed to finance the remaining one-third and sections of sewage works not covered under the federal plan. By 1965, the capital and operating costs of approved municipal projects could be paid for by OWRC and recovered through service charges to users based on actual usage.

In the late 1960s and early 1970s, phosphorus removal from sewage effluent became a major concern. Phosphorus draining into the water bodies promotes an excessive growth of water plants. The decay of these plants deprives the water of the oxygen necessary for
other aquatic life.

As a good part of the phosphorus enrichment of Great Lakes waters was provided by the effluent of sewage treatment plants, a province-wide phosphorus and other nutrient control program was established in 1971. The program established 1973 and 1975 as deadlines for phosphorus removal facilities at 210 municipal sewage treatment plants.

On April 1, 1972, the OWRC was integrated into the new Ministry of the Environment which continued with the work initiated by the commission.

U.S. – Canada agreement sets objectives

Under the Canada-Ontario Agreement, the Ministry of the Environment was responsible for the phosphorus removal program. In 1976-77, the provision for phosphorus removal at all significant municipal discharges was completed.

In November, 1978, a new U.S. -Canada agreement set new Great Lakes water quality objectives. They involved tighter controls in the discharge of toxic substances, new phosphorus loading targets and dates for the completion of municipal and industrial pollution abatement programs, and objectives regarding radioactivity.

By 1 980, 220 Ontario wastewater treatment plants with phosphorus removal facilities removed 7,000 tonnes of phosphorus yearly from sewage plant effluents.

In the fall of 1980, the first stage of the York-Durham water pollution treatment system, under construction by Environment Ontario since 1975, was officially opened. While the sewage treatment systems in other communities grew piece by piece following the growth of the municipalities, the $300 million York-Durham system is the largest single planned sewage system in Canada. It is designed to serve the’ present and future needs of the Regional Municipalities of York and Durham with a population expected to grow to 800,000 people.

In 1982 there are 360 publicly owned waste water treatment plants in operation in the province, most of them offering secondary treatment and many of them also providing tertiary treatment or phosphorus removal. They handle together over I billion gallons of sewage daily.

Of the total, the province operates 213 facilities, mostly in smaller municipalities that are unable to afford the full cost of adequate treatment. Municipalities operate 147 facilities handling 74 per cent of the total waste water treatment capacity in the province. Communal waste treatment systems now serve 94 per cent of Ontario’s urban population or 82 per cent of the total population.

The number of stages of treatment required depend upon the nature of the waste to be treated and the effluent quality necessary to adequately protect the environment.
Today, methods are constantly being revised and fine-tuned but activated sludge systems are the main treatment methods used. They remove up to 95 per cent of
the organic matter and BOD.

Primary treatment or sedimentation removes up lo 60 percent of the organic matter and 35 percent of the BOD. and a negligible amount of bacteria unless disinfected: this method is allowed where conditions warrant it. Tertiary treatment removes up to 98 per cent of the organic matter and is used generally on small rivers, such as the Don.
Grand and Thames. Phosphorus is removed by the addition of chemicals in the last stage of treatment.

Progress has been made over the years but, whereas once domestic sewage was the main concern, we now face new and more complex problems with the discovery of numerous hazardous substances — toxics, heavy metals and oil. Some toxic chemicals are highly persistent and accumulate indefinitely in biological tissues and in the environment.

We impose a great number of intensely conflicting demands on our water resources — health, recreation, fisheries, wildlife, esthetic purposes, navigation, and waste disposal — and we have high expectations for a good quality aquatic environment. Let’s hope we stop the trend of continuing misuse and meet this new challenge as we did the old one — typhoid.