The City of Hamilton, Ontario’s Water Treatment Plant is one of the oldest in Canada and is located on the same property as the Wastewater Treatment Plant. Stainless Steel World Americas had the delight of touring both the water and wastewater sides of the Woodward Avenue Facility.
In Part One, Richard Fee, Water Treatment Plant Supervisor, details the evolution of the water treatment process, the plant’s continued growth, and the important role of various assets throughout its process.
By Charlie Evans
The City of Hamilton, Ontario began treating its water in 1859. The facility started the way most water treatment plants did, as a resource for fire protection. Over time, after a city-wide cholera epidemic, the facility was transitioned into a water treatment plant to provide clean drinking water for the area’s citizens. The founders of Hamilton decided on the location of the plant with highly forward and long-term thinking. The choice was simple, it was based on the natural geography of Hamilton and the proximity to Lake Ontario.
The chosen location allowed for wastewater to flow to the treatment plant by gravity and raw water to be pumped from the lake for drinking water. “It is why both of our plants, the water and wastewater facilities, are located together on the same property,” said Fee.
“We use the topography to our advantage, which makes our facility slightly different than a typical plant.” Subsequently, the operating procedures of this plant also differ as they use the Niagara escarpment to make the plant as efficient as possible.
As the Water Treatment Plant Supervisor, Fee works hard to manage the water plant on a day-to-day basis. “I look after the daily activities of the plant, overseeing the staff, processes, and operational activities,” explained Fee.
The Water Treatment Process
The water treatment process has several process steps to ensure that proper, clean drinking water is sent out to Hamilton and the surrounding serviced areas. The water is filtered from Lake Ontario, entering an intake pipe, and then pumped into the Woodward Avenue Treatment Facility, wherein the water is then filtered and treated.
The plant’s average daily production is about 200 MLD, a fraction of its 900 MLD capacity. This process includes the following:1
• Pre-chlorination,
• Screening,
• Clarification by means of coagulation with polyaluminum chloride,
• Flocculation by mechanical mixing,
• Sedimentation,
• Filtration by 24 dual media granular activated carbon filters,
• Chlorine and ammonia are added to the filtered water to provide secondary disinfection throughout the distribution system,
• Hydrofluosilicic acid (fluoride) is added to the drinking water to promote dental health.1
Each step is vital to the completed process of supplying residents with safe and clean drinking water. For example, an aspect of the filtration system is backwashing the filter. In this process, the flow of water is reversed and fed backward to rid the system of unwanted debris and unwanted floc particles, ensuring the filter’s cleanliness and the drinking water’s high quality. The backwashed water is then sent to the wastewater plant at the facility. The finished treated water is stored in large clearwells prior to being pumped into the distribution system based on usage.
Each process is complex and consists of multiple assets that all play an important part in the overall treatment system. In particular the network of pumps, valves, and specific grades of stainless steel work together to provide a final product for the city.
The Role of Pumps
Pumps play an extremely significant role in the water treatment process. The system comprises primarily centrifugal pumps that move the water through the process. The low-lift pumps convey
water from Lake Ontario through the treatment process into large tanks for storage.1 From there high-lift centrifugal pumps send water into the water distribution system.
The first pumping station, known as the Beach Pumphouse, was built in 1860. It is now out of operation and known as the Hamilton Museum of Steam and Technology. At this time in Hamilton’s water history, there was a filtering basin located at the beach. The lake water percolated through the sand filter as the water was pumped from the Beach Pumphouse via steamdrive pumps to an open reservoir known as the Barton Reservoir.
When the waterworks were overhauled, between 1910 and 1914, the installation of electric-driven pumps was a priority, as the previously used steam-driven pumps had been in operation for 50 years and were inefficient in keeping up with the water demand. The steam-driven pumps were then placed on standby before finally being abandoned in 1938.
The Hamilton distribution system includes 23 distribution pump stations, a low-lift and high-lift pump station, 8 wells, 10 towers, and 10 reservoirs which convey water to all parts of the distribution system and ensure adequate pressure for customer use and for fi re protection.
Pumps are maintained and repaired by the City’s Plant Maintenance team or replaced when at the end of their useful life. Replacement of pumps is, where possible, coordinated with larger rehabilitation projects to ensure efficient use of rate-payers funds.
The Role of Stainless Steel
316 stainless steel is the most widely type of stainless steel used in the facility. It is utilized in sluice gate valves and many of the piping systems. This grade is chosen due to its low resistance to corrosion or oxidization. Corrosion of materials is an ongoing concern at the water facility, monitored on an ongoing basis to preserve both the maintenance of the parts as well as the quality of the water. There is the potential for corrosion due to the chemicals added during the water treatment process. The choice of stainless steel allows for a long-lasting material that requires far less maintenance and repair than others.
Some lower grades of material are used elsewhere in the plant, such as 304 stainless steel which is used in outdoor cabinets that run the risk of weather-caused corrosion.
The Role of Valves
Valves play a role. For example, specialized control valves are use in applications where volumes and flow rate need to be maintained in processes such as filter backwashing. In this scenario the valves allow the proper control to stop the flow of water when necessary.
“The type of valve is usually determined by the design engineer for each application,” explained Fee. “We use a lot of ball valves on various systems in our water plant, typically of two inches or less. There are very few globe valves, except for on heating or cooling systems.”
The majority of valves inside the water plant are either large sluice gates, such as inlet gates to clarifiers, or sedimentation basins driven by an electrical stem-mounted actuator or Acme-treated spindles. “When there are chemical systems, we typically use Chem-line PCV ball valves, as well as pneumatically operated ball valves on some of the polymer systems,” Fee continued.
The plant also has a valve exercise program in place to operate valves that are not used regularly. This helps to ensure that all valves are in working order, despite not being used frequently, which is a form of preventative maintenance at the plant.
Moving Forward
Despite an increasing population, water use remains stable. “Thanks to education and conservation the introduction of low-flow toilets, showerheads, offsets increases as development occurs. Additionally, industry has over the years become more efficient in their water use, largely to reduce operating costs. Whether intentional or not, consumer choices are affecting water conservation in a beneficial way.
The future of the water plant is ensured by constant updates to improve the facility providing the residence of Hamilton access. Each of the industrial assets works hard to make this possible.
Reference:
1. https://www.hamilton.ca/home-neighbourhood/waterwastewater-stormwater/water-treatment- distribution/drinking-water-system
Stay tuned for Part Two of this article discussing the Wastewater Treatment Plant of the Woodward Avenue Facility in Stainless Steel World Americas Journal.