In addition to storage lagoons only designed to hold waste for pumping, most sewage ponds fall into either the processing or polishing category of treatment. Both stages are essential to turning raw sewage into water safe enough to release into the environment. Some sewage may only need basic processing from a single treatment stage, while other mixtures require the further stages known as polishing. Don’t be confused by the similar names for two very different stages of treatment. Find out how processing and polishing lagoons work together to achieve the highest quality wastewater results.
Different Stages of Treatment
Processing is the primary stage of treatment for sewage and mixed wastewater. The majority of large in-ground ponds designed as wastewater lagoons are used as processing spaces. All the primary methods of passively and actively improving sewage wastewater are considered processing treatments. Secondary cells are used for polishing the wastewater by further settling out fine particles or evaporating chemicals. The total surface area of secondary polishing cells should be at least half of the processing stage. Polishing doesn’t need as much surface area as processing since the wastewater is cleaner by the time it reaches that stage, but the lagoons still need durable and chemical resistant liners from BTL Liners.
Is Polishing Possible at the Residential Level?
Most residential sewage lagoons are a single cell that primarily processes the waste. This is handled with passive evaporation in the majority of systems. However, homeowners interested in discharging water to a nearby open field or body of water can invest in a system that includes secondary ponds for polishing. Reed beds and other constructed wetland cells help accelerate polishing, so water is as clean as possible before it exits the system. If a residential system will be designed for discharge, it should definitely include at least one layer of secondary treatment for polishing. Even polishing methods that require powered filters and pumps are possible at the homeowner level.
Equipment Needed for Both Types of Lagoons
All processing and polishing lagoons share a need for connecting plumbing, pumps, and filters to keep water quality in check. Pumps and plumbing help moving sewage from the source and into the primary and secondary treatment stages. Filters aren’t used in all lagoons, but they are commonly included in the form of natural and bio-active filters like reed beds.
Both polishing and processing can only occur if the majority of the water stays in the various lagoons and ponds during the treatment periods. Some anaerobic systems must hold water for multiple months in occur to completely process out unsafe levels of bacteria and other contaminants. Most states require these lagoons to lose 1/8th of an inch of water per day or less to leaks and seepage, so you’ll need a quality liner from BTL Liners to achieve this level of control.
