One of the most reliable sewage treatment systems on the market is a Sequential Batch Reactor (SBR) type system. As the name suggests, the sewage is treated in batches, not as one continuous flow. The advantage of this is that a shock load of a sudden inflow of sewage is buffered, and does not force partially treated or untreated wastewater to be discharged. Instead the incoming sewage is stored until the reactor is ready to treat it.
The system is made up of two chambers within a tank. The first chamber stores the wastewater and also provides primary treatment in the form of settlement of heavy solids. The second chamber is the reactor which houses the treatment equipment made up of two pumps and a mechanical aerator.
The treatment of the wastewater is completed in an 8 hour cycle. At the beginning of the cycle a batch of wastewater is drawn across to fill the reactor. Once the reactor has been filled, the 6 hour treatment phase begins. The aerobic bacteria which breaks down the organic waste thrives in oxygen, so in order to increase the efficiency of the system, oxygen is added to the wastewater by a mechanical aerator. The aerator mixes the wastewater with an impeller and introduces water through an air intake hose. This increases the dissolved oxygen level. Aeration is an intermittent process tailored specifically for each household situation. This ensures both optimum treatment and reduced power consumption.
At the end of the treatment phase, clarification occurs by leaving the reactor undisturbed for 2 hours. This allows suspended solids to settle to the reactor floor, preventing them from being discharged. After clarification, the treated and clarified water is pumped out into a suitable percolation area.