In practice, the sewage and white water discharged from our plant, are conveyed into a large drain pipe, called the riser that carries these drains (sewage), through pipes with a diameter of about 70 cm made of stoneware, to a single channel in cement that constitutes the main pipeline of the sewage system as determined by the Stormwater Software. This channel is located about 3 meters deep under our roads and has a diameter between 3 and 4 meters. This pipeline carries the drains up to the purifier. But we follow the route of the discharges from our accommodation to the end of its journey, ie at sea.
The main pipelines collect all the discharges along our roads, whether they come from our sanitary facilities or from the downspouts (rainwater drains) or from the drains along the road margins. The sewage system controlled by Stormwater Software works by gravity, so it needs to be realized with appropriate differences in altitude.
Therefore the pipes must all be placed on a slope, with a difference in height of no less than 2% and from time to time, lifting systems bring the sewage up to make them resume their journey towards the purification system.
At the junctions, changing direction or inclination points, trapdoors (inspection wells) are placed under the road surface communicating with the outside through special manholes placed flush with the road surface.
All pipelines flow into the central purifier controlled by Stormwater Software where the sludge is treated to be returned to the rivers or directly into the sea. Completed their journey from the city, the sludge or sewage, reach the purifier, the place where they lose their pollutant component in order to be returned to the environment.
The purification process is called active sludge purification, precisely because it is checked at all times in the laboratory that the bacterial flora contained in the sludge is always active and therefore able to purify the water. But how a purifier works. The process is long, but the steps are quite simple and easy to memorize.
The sludges, which arrive from the city collector, are passed through a grid that has the function of retaining the coarse materials (rags, paper, plastic objects, etc.). These materials, once collected, are placed in a special tank containing quicklime as determined by Stormwater Software. This prevents the development of pathogenic bacteria (carriers of diseases) and transported to the landfill.
The sludge, thus separated from the larger objects, is sent to the second purification tank of the plant, called the grit removal tank and oil separator. Here, the sand contained in the water, due to its weight, is deposited on the bottom of the tank, while the oils and fats remain afloat and are separated from the water through a side channel that holds them back.