Water Reclamation Center

At the headworks building of the Water Reclamation Center, the incoming wastewater flows through screens designed to capture large objects such as sticks, rags, plastics, and other debris. This initial screening prevents damage and blockages in the subsequent treatment processes. After screening, the wastewater passes through a grit chamber, where smaller particles like sand and gravel are allowed to settle out. These gritty materials, often heavy and abrasive, are then removed from the bottom of the chamber. This step is crucial for protecting pumps, pipes, and other equipment from excessive wear and tear, ensuring that the system operates efficiently as the water moves to the next stage of treatment.

Aeration is a critical process where large amounts of air are pumped into the wastewater. This infusion of oxygen supports the growth of aerobic bacteria, which are naturally occurring microorganisms that consume organic pollutants, breaking them down into simpler, less harmful substances like carbon dioxide, water, and biomass. The aeration process takes place in one of our four aeration basins, where the wastewater is thoroughly mixed with air using diffusers and mechanical mixers. This step significantly reduces the biological oxygen demand (BOD) and the concentration of organic matter in the water, making it much cleaner as it continues through the treatment process.

After aeration, the partially treated water flows into large settling tanks known as clarifiers. The Water Reclamation Center currently operates four clarifiers. In these tanks, the heavier solid particles, now referred to as sludge, settle to the bottom due to gravity. The sludge is then scraped, collected, and pumped from the bottom of the tank for further treatment. Meanwhile, the clarified water at the top is skimmed to remove any remaining floating particles such as fats, oils, grease, or small pieces of trash. The water then gently flows over weirs—a series of small barriers designed to evenly distribute the water as it exits the tank. This clarified water, now significantly cleaner, is directed towards the UV disinfection stage for final purification. The clarification process plays a vital role in separating solid waste from the liquid, ensuring that only the lightest and smallest contaminants remain in the water.

Digestion is a process similar to aeration, but it occurs under conditions with significantly lower oxygen levels. In this stage, the sludge from the clarification process is transferred to one of four large tanks where it undergoes further biological treatment. Here, the oxygen supply is carefully controlled to create an environment where specialized microorganisms can thrive. These microorganisms continue to break down the organic material in the sludge, but at a slower rate due to the lower oxygen levels. This process further reduces the volume and harmfulness of the sludge, stabilizing it and minimizing odors. The digested sludge is then transferred to holding tanks where it will be pumped to the press building for dewatering or land applied.

De-watering is the process of further reducing the water content of the stabilized sludge, transforming it from a liquid or slurry into a more solid, cake-like material. At the Water Reclamation Center this is achieved using a screw press. A small amount of thickening agent is added to the sludge as it enters the screw press, the water is then pressed out and returned to headworks. The resulting de-watered sludge is much easier to handle, transport, and dispose of, as its volume is significantly reduced. The de-watered sludge contains valuable nutrients that are repurposed via land application.

After thorough testing biosolids can be safely applied to agricultural land as a nutrient-rich fertilizer. The application of biosolids to land recycles valuable organic material back into the environment, enriching the soil with essential nutrients like nitrogen, phosphorus, and organic matter, which support healthy crop growth. This sustainable practice not only reduces the need for chemical fertilizers but also improves soil structure and fertility, promoting long-term agricultural productivity. Our process is carefully managed to ensure that the biosolids are applied in a way that protects public health and the environment.

The final stage at the Water Reclamation Center is UV disinfection. In this stage, the clarified water flows through a chamber where it is exposed to ultraviolet (UV) light. The UV light penetrates the cell walls of microorganisms, such as bacteria, viruses, and protozoa, disrupting their DNA and rendering them unable to reproduce or cause harm. Unlike chemical disinfectants, UV treatment does not leave any residual chemicals in the water, making it a safe and effective method for ensuring the treated water is free of pathogens. Once disinfected, the water is safe to be released into McCoy Creek, where it can re-enter the natural water cycle without posing a risk to public health or the environment. Check out the Stormwater Management Division to learn more about McCoy Creek and its success story!