The Biddeford And Saco Water Company operates a 13 MGD Conventional Water Treatment Plant. Every drop of water delivered to our customers is processed through our treatment facility which is composed of a series of treatment barriers (five total) to ensure the removal of pathogens and substances regulated under the US EPA Safe Drinking Water Act. The treatment barriers are, chemical coagulation, flocculation, sedimentation, filtration, and disinfection. Each "barrier" is looked at as its own distinct process. We continuously review our operations to optimize the efficiency of each barrier, the end result being the consistent production of water which meets or exceeds all water quality parameter regulated under the Safe Drinking Water Act. In 1998, our treatment facility was among the first in the nation to be awarded a "Directors Certificate" by the Partnership For Safe Water for outstanding water quality well in excess of current regulatory standards and treatment facility optimization efforts.
      The original treatment facility was constructed in 1884 with coagulation and filtration being added between 1895-1900. In 1936, a major modernization and expansion of the facility was completed, resulting in the facility still in use today. The current treatment facility, now over 60 years is a fascinating blend of old and new drinking water technologies. Unusual in today’s age of computer automated treatment facilities, our facility is one of the last in the country still manually operated. The facility boasts an extensive array of some of the most "state of the art" instrumentation available in the industry. This instrumentation includes chlorine analyzers, turbidimeters, laser particle counters, and streaming current detectors to help plant operators make prudent decisions to ensure water quality standards are consistently met. The installation of new pumps over the years has increased the facility’s maximum output from it’s original design of 10 million gallons per day to it’s present maximum of about 13 million gallons per day.


Coagulation-

This is the first treatment process, and begins immediately as the water is drawn from the river into our facility. The goal of this process is to chemically convert dissolved naturally occurring organics in the river water into solids. Most of the organics we see are from the decomposition of leaves and plant material within the watershed which give the river water it’s typical brown tea color.
We add a combination of Aluminum Sulfate, Sodium Aluminate seasonally, and Calcium Hydroxide (lime) to properly condition the water. This chemical conditioning, which is an instantaneous reaction, is critical because failure to convert the organics to a solid can severely compromise the efficiency of the next three treatment barriers. To ensure proper chemical conditioning at all times we utilize two continuous on-line Streaming Current Monitors. These instruments measure the net electrochemical charge of this chemical process ensuring that optimum conditions are maintained at all times.
This entire process occurs within the piping network of our intakes, low lift pumps, and feed lines to the influent of the sedimentation basins.

Flocculation-

This is a physical process. The tiny pin head size particles created in the coagulation process are gently mixed, and as they collide, they join together creating larger sized particles. We will occasionally add a slight dosage of polymer, which is a sticky compound to help the particles bind together. We are currently replacing our static flocculators with two stage mechanical mixers. The first phase of this project was completed in early 1999 and is working extremely well. We intend to complete this multiphase project in the coming year. This entire mixing process typically lasts about 25 minutes.

Sedimentation-

This is a physical process. The floc particles are now introduced into large, deep retangular shaped basins where the velocity of the water is greatly reduced allowing the floc particles to settle out of the water stream. This process typically lasts about 2 hours. The water, now relatively free of floc particles is then piped to the next treatment barrier. The photo to the left shows one of our settling basins while empty. When in operation (full) the water level is approximately one foot below the wall on the right or about 17 feet deep! The combined volume of our two basins is about 1.3 million gallons.

Filtration-

This is a physical process. Effective filtration ensures that potentially harmful microorganisms are removed and ensures the removal of particulate mater that could have a detrimental effect on the disinfection process. The "settled" water, now relatively free of floc particles is passed through filters consisting of about 5 feet of sand and anthracite coal. The first application of chlorine is made at this point to minimize biological growth on the filter media. The extremely high quality water emerging from these filters is continuously monitored for turbidity (a measure of cloudiness or suspended particles). The filters require regular maintenance in order to operate efficiently. Filters are backwashed (cleaned) at a frequency dependant on their finished water quality. All individual filter units possess state of the art turbidity monitoring instrumentation linked to a SCADA (Self Controlled Automated Data Acquisition) system which immediately alerts plant staff of inefficient filter performance. We were the first filtration facility in Maine to introduce laser particle counting technology to this process. This instrumentation qualifies and quantifies particulate breakthrough from the filter as small as two microns in size (two thousandth’s of an inch!). It has proven to be a very effective tool to improve filtration performance.

Disinfection-

This is a chemical process and is considered the final "treatment barrier" before the water is delivered to the public for consumption. Disinfection is the inactivation of organisms harmful to man. We use chlorine gas as a disinfectant. A slight dosage of chlorine is injected to the water at the end of the filtration process. All filtered water is introduce into a series of water storage tanks located within the treatment facility which we call Clearwells. Federal drinking water regulations require that minimum disinfection standards be met at all times before the water can be delivered to the public. The water is held within the treatment facility in these storage tanks until at least the minimum disinfection requirements are met before it is pumped to the public for use. We carefully monitor the chlorine residual in this process using continuous on-line analyzers to ensure that federal disinfection standards are continuously met. The accuracy of our chlorine process instrumentation is verified in our laboratory hourly by plant staff to ensure its accuracy. We try to add the minimum amount of chlorine at all times to minimize customer complaints, but Federal drinking water standards do require that a disinfectant (chlorine) be added to the water at all times.

Special Water Quality Programs-

A description of our treatment process cannot end without mention of other special water quality programs. Although not part of the "multiple barrier" treatment concept described above, we feel these programs are of significant importance to the water quality supplied our customers.

Fluoridation Program-

In 1987, our customers voted in support of a referendum to implement fluoridation of the public water supply. Fluoridation is the introduction of a fluoride compound to drinking water for the prevention of tooth decay. The Saco River typically has about 0.3 mg/l of naturally occurring fluoride, so we add approximately 0.8 mg/l of additional fluoride. We carefully monitor the fluoride residual to maintain a 1.2 mg/l residual as mandated by the State Of Maine, Dental Health Program.

Corrosion Control Program-

The Biddeford And Saco Water Company has maintained a formal corrosion control program for over 50 years to control corrosion of distribution system and customer owned piping. Corrosion of plumbing materials can cause elevated levels of iron, lead, and copper in the drinking water. We utilize a phosphate based corrosion inhibitor to minimize the corrosivity of the drinking water.

Backflow Prevention Control Program-

The Biddeford And Saco Water Company maintains this program to help minimize the potential of accidential contamination of the distribution system. The State Of Maine, Plumbing Code requires that any customer who connects a potential source of contamination to a water supply install, register, maintain, and have regularly tested a device which prevents water from flowing back into a water main after flowing through the meter.