Primary tanks are designed for the first step of each wastewater treatment system.
If we want to purify the wastewater that comes out of our homes, we obviously need to contain it, which is the first task of a septic tank.
Most importantly, the main tank will provide sufficient time for the wastewater to be deposited and rinsed out. This is why they are often referred to as primary clarifiers or sedimentation tanks. A septic tank is an airtight buried tank designed and constructed to receive and partially treat untreated domestic sanitary wastewater.Heavy solids settle to the bottom of the tank, while fats and lighter solids float to the top. The solids remain in the tank while the wastewater is discharged to the drain field for subsequent treatment and dispersion. Modern tanks are also equipped with effluent filters, which are designed to keep small solids floating in the tank and out of other components of the septic system (where they can cause problems). Advanced treatment systems are designed as a “treatment train” or a logical sequence of treatment components to achieve a certain level of treatment, which can be specified by local, state, or regional government agencies.
A septic tank specifically collects fats, oils, and solids; however, its effluent requires additional purification to prevent any hazardous contaminants from entering the environment. Purification performance is by far the most important difference between septic tanks and wastewater treatment plants. Sand filters provide a high level of nutrient treatment and are good for sites with high groundwater levels or that are close to bodies of water, but are more expensive than a conventional septic system. However, for better water purification, it is possible to adapt most septic tanks with a wastewater treatment plant (see our ECOROCK solution). The most common type of septic tank is built with concrete, although fiberglass tanks are used regularly in lots with limited access to heavy equipment.
Septic tanks are an outdated technology in terms of wastewater treatment, requiring a second stage to produce clean, environmentally safe effluents. If you're looking for an environmentally friendly way to dispose of wastewater, you might be wondering if a septic tank is the right option for you. It is a misunderstood assumption to refer to septic tanks and wastewater treatment plants as one thing, when in reality they are two very different entities that serve to purify waste. While a septic tank has similarities to the primary stage of wastewater treatment, it's not sufficient to qualify as an effective water treatment plant.
The reliance on native soils for wastewater treatment can be a major constraint in areas where soil conditions are not ideal for sewage infiltration and treatment, or where the available land surface is insufficient to handle large water loads. Some aerobic systems may also have a pretreatment tank and a final treatment tank that includes disinfection to further reduce pathogen levels. Unlike a septic tank, wastewater treatment plants can easily treat large amounts of wastewater and even “shock loads” with comfort.
