Getting water to you

Aluminum Sulphate or "alum" is a coagulating agent that is injected in the water at a respective dosage that is dependent on the raw water quality. In the flash mix or rapid mix chamber the alum is dispersed evenly with the aid of a mixer. 

After the alum is dispersed in the water, its positive charge allows for the attraction with negatively charged particles. The "dirt" in water mostly carries negative charge and therefore coagulates with alum. With the aid of the baffles and slow mixers, these particles collide together to form "flocs." As the flocs grow in size, due to the contact created as a result of slow mixing, they become heavier and easier to settle (Sedimentation). 

After the water has passed through the last baffle, it is fed into the “Clarifier” to begin the “Clarification Process”. There is a Clarifier in use for each respective plant at the Double Run facility, Plant A and Plant B. The Clarifiers’ purpose is to remove any additional organic material that escaped sedimentation adding more clarity in the process.

Water flows through the Clarifier basins where a large portion of the floc settles at the bottom as sludge. A “Rake Arm” is used to slowly rake the settled sediments and sludge at the bottom of the clarifier for easy cleaning and disposal. Plant B employs the use of “Lamella Plates” to assist with the sedimentation of particles and increase of flow in the clarifier. This sludge is drained three times daily to reduce sludge build-up. Clarified or "settled" water then flows over the top into the launders and to the next stage in the water treatment process.

At this point in the process, the water looks clear, but there is still bacteria and other very small particles suspended in the water. Particles that have not been separated are removed by filtration. The different layers of filtration material include stone, gravel, sand, and anthracite. Using the Rapid Sand Filtration process, the water flows through a bed of filter media where particles are caught as they run out of space to flow through these filters.

All filters are cleansed using a backwash process twice a day. In this process, a flow of clean water and air are reversed from the bottom of the filter bed to dislodge any remaining particles. This water carrying the dirt, known as backwash effluent, exits through the top of the filter basin via overflow drain.

At the end of the filtration process the water is clear, but disinfection is required to ensure the proper removal of harmful bacteria and or pathogenic microorganisms. 

For the water to be classified as safe for consumption (Potable), the water must be disinfected to kill any remaining harmful microorganisms and or disease-causing pathogens. Disinfection is done via Chlorination at Double Run Water Treatment Plant by using Calcium Hypochlorite (Chlorine). 

The Chlorine Treatment requires adequate contact time of about thirty (30) minutes in order to effectively kill bacteria and other pathogens from the water. The design of the system from the Disinfection stage to the Distribution stage provides the necessary contact time for an effective treatment.

Below the HighLift Pump Station building the potable water is stored in clear wells awaiting Transmission and Distribution to various reservoirs and consumer homes.

The Distribution System includes a 24-inch transmission main that feeds water to three (3) reservoirs in Belize City. These reservoirs are located at the Belize Water Services Headquarters on Central American Boulevard, and on Wilson Street in Belize City. These reservoirs supply water to customers in the Belize City Southside Area through mile 10 on the George Price Highway as well as the Northside Area.

The Distribution Systems also has a 14-inch distribution main line that works 24/7, to supply water directly to all customers from Princess Margaret Drive all the way up to mile 29 on the Northern Highway, including Burrell Boom and Belize River Valley if needed.