Basic information and specifications of relevant supporting facilities
Grille is the core auxiliary equipment of sewage pumping station, and usually consists of a group of parallel bars, which are obliquely arranged at the inlet end of the sump of the pumping station with an inclination angle of 60 ~ 80. A workbench should be set behind the grille, and its elevation should usually be 0.5m higher than the highest water level upstream of the grille. When using manual slag removal, the length of the workbench along the direction of water flow should not be less than 1.2m；; When mechanical slag removal is adopted, the length should not be less than 1.5m, and the width of the aisles on both sides should not be less than 0.7m.
brief introduction
Pollutants in sewage usually exist in three forms: suspended (including floating), colloidal and dissolved. The main objects of sewage physical treatment are suspended solids and some colloids that may block the impeller of water pump, pipeline valves and increase the load of subsequent treatment units, so sewage physical treatment is often called wastewater solid-liquid separation treatment. In principle, the solid-liquid separation of wastewater is mainly divided into two categories: one is that when the flow of wastewater is limited, the suspended solids are intercepted and removed with the water flow; The other is that when suspended solids are limited, suspended solids will be intercepted by wastewater flow. Grille belongs to the latter, as the core auxiliary equipment of sewage pumping station, it usually consists of a group of parallel bars, which are obliquely arranged at the inlet end of the sump of the pumping station.
classify
According to the structural form, the grille can be divided into two types: plane grille and curved grille. The plane grid consists of grid bars and a frame; Curved surface grille is further divided into fixed curved surface grille and rotating drum grille.
According to the grid spacing, it can be divided into three types: coarse grid (net spacing of 50~100mm), medium grid (10~40mm) and fine grid (1.5~10mm). Both plane grid and curved grid can be made into three types: coarse, medium and fine. As the grid is the key facility for physical treatment, newly-built sewage treatment plants usually have two grids, namely coarse grid and medium grid, and some projects even use three grids, namely coarse grid, medium grid and fine grid.
According to the slag cleaning method, the grille can be divided into manual slag cleaning grille and mechanical slag cleaning grille. Manual slag removal grid is suitable for small sewage treatment plants; When the amount of grid slag exceeds 0.2m/d, in order to improve the working environment and working conditions, mechanical slag removal grid should be adopted.
