Drain Inlet Protection consists of a tank with separate overlapping compartments that realizes in a single container the one that runs in several tanks of a purifier. It consists of two underground prefabricated reinforced concrete compartments. In the upper one we have the primary sedimentation tank, while in the lower one we have the anaerobic digestion sludge tank.
The upper basin generally consists of a top part with a rectangular section and a lower part with a longitudinal slot through which the sedimentable sludge passes. The hygienic principle that is the basis of every modern sewer system is to obtain the fastest possible removal of human waste and other putrescible waste from homes, to avoid the spread of infectious diseases and the development of nauseating gases harmful to health .
The sewage pipes must therefore be waterproof channels, to prevent any infiltration into the subsoil. Harmful water means both waste water (black water) and rainwater (white water). Wastewater includes both domestic water, which comes from homes but also from public and private buildings, and water produced by cleaning and watering roads; and the waters used by the factories of the industry.
Sewerage is generally natural: sewage flows by gravity from a conglomerate to the purifier. During this route, depending on the obstacles in the area or the height requirements, lifting systems may be present, which mechanically lift the waste water through a series of electric pumps to allow the next route.
Networks can be of two types, mixed or separate. The separate networks have a double piping system: one dedicated to the collection of civil or industrial wastewater up to the purifier, and one dedicated exclusively to the collection of meteoric drainage water, which is sent to surface waterways. Mixed networks, on the other hand, collect both civil / industrial wastewater and meteoric drainage water in a single duct, and along the way have “overflow chambers” that allow the flow of excess flow into the waterways.
The purpose of the Drain Inlet Protection technique is to generate a slight cementation or true cohesion between the grains of the soil by penetrating into the interstitial pores an appropriately calibrated binding mixture (eg silicatic solutions or suspensions). Cementation causes an increase in liquefaction resistance, a reduction in permeability and an increase in stiffness.
The success of the treatment depends on the permeability of the soil layer and the penetrability of the mixture within the layer. It is therefore necessary to carefully select the product to be injected, which must not shift the soil grains (displacement, claquage phenomena), but must permeate them. Generally the silicate solutions or suspensions are highly penetrating, while cement-based mixtures have a limited range of use only for coarse-grained soils.