HUBER Grit Treatment System

More product information

Function

2. Process description
The sequence of the RoSF 5 Process is explained in the diagramm. The individual process steps are described as follows.

2.1 Process components
Feed possibilities:

a) Dry feed of the underground intermediate storage tank from e.g. tankers and dosing of raw material from the tank into the wash drum or the grit washing plant by means of a vertical screw conveyor according to the dimension sheets tank 6, tank 9 and tank 15.

b) Dry feed of the surface or underground storage tank from e.g. tankers (underground) or loaders (surface) and dosing the raw material from the tank into the wash drum by means of a horizontal screw conveyor according to dimension sheets tank 4 and tank 9.

c) Wet feed of the underground intermediate storage tank from e.g. tankers and dosage of raw material into a pump sump via horizontal screw conveyor according to dimension sheets tank 4 and tank 9 and layout sheet RoSF 5/HP. The Coanda-Grit Washing Plant is directly fed from the pump sump.

2.2 Dry feed of the underground intermediate storage tank according to dimension sheets tank 6, tank 9V and tank 15

The material nearly dewatered which has to be treated is fed into the intermediate storage tank via e.g. tankers. A bar rack is installed in order to remove big components. Depending on the raw material quality, external vibrators additionally attached to the bar rack guarantee a good flow of material through the rack. A vertical screw conveyor removes the material and feeds the ROTAMAT-Washing Drum. In case of a larger intermediate storage tank, a horizontal screw conveyor transports the material to the vertical screw.

Higher quantities of liquid which possibly accumulate can be directly pumped into the channel or the drain via a small submerged pump.

Volume of the storage tank has to be adjusted to the necessary regulation capacity regarding the raw material delivered. It has to be made of stainless steel or concrete.

2.3 Dry feed of the surface or underground regulation tank according to the dimension sheets tank 4 and tank 9

Underground version:
The material nearly dewatered which has to be treated is fed into the intermediate storage tank via e.g. tankers. A bar rack is installed in order to remove big components.

Surface version:
The material is fed into the regulation tank e.g. via loaders. A bar rack is installed in order to remove big components. Depending on the raw material quality, external vibrators additionally attached to the bar rack guarantee a good flow of material through the rack. A vertical screw conveyor removes the material and feeds the ROTAMAT-Washing Drum which is installed under ground as well in case of a underground tank version.

Volume of the storage tank has to be adjusted to the necessary regulation capacity regarding the raw material delivered. It has to be made of stainless steel or concrete.

2.4 Wet feed of the underground regulation tank according to dimension sheets tank 4 and tank 9 and layout sheet RoSF 5/HP

Raw material (solids and water) is directly added to the regulation directly from the tanker. The tank is covered by a bar grate (mesh size 30 x 30 mm) in order to keep back big components. Several external vibrators additionally cause a good flow of material through the grate. An automatic valve at the end of the horizontal screw conveyor inside the pump sump is still closed.

When a maximum filling level is reached, the liquid phase flows from the regulation tank into the customer-supplied pump sump (made of concrete). At a certain water level inside the pump sump, a submerged pump conveys the grit/organic/water mixture directly into the Coanda-Grit Washing Plant RoSF 4.

When the tanker is empty, the automatic valve opens and a horizontal screw conveyor regularly doses solid matter into the pump sump. At the same time, transport water which is controlled by an automatic shutoff device flows into the pump sump. Waste water from the grit trap (inlet via gravity line or grit pump) is used as transport water as far as this can be realised. Level measurement controls the inflow of transport water into the pump sump during operation.

Rain water which seeps into the shaft of the regulation tank, is transported into the pump sump by a small submerged pump operating via level measurement independently on total control.

2.5 ROTAMAT-Wash Drum

First, the material is homogenised in the ROTAMAT-Wash Press by drum rotation and added wash water, i.e. bigger conglomerations are broken up. At the same time a spray bar washes components < 10 mm out which then reach a pump sump below the rotating drum. Coarse material > 10 mm are kept back by the rotating perforated plate and at the end of the wash drum they are discharged in dewatered condition into a container provided. A spray bar which is at the outside of the wash drum cleans the screen surface.

2.6 Wedge Section Screen Ro 2 in a container

The total outflow of the Grit Washing Plant RoSF 4 is led into the ROTAMAT-Wedge Section Screen Ro 2. There, all organic components > 1 mm are removed and discharged into a container in dewatered condition. The rotating screen drum is cleaned by a spray bar. Operation of the screen drum is controlled via differential level measurement.

This water which is now free of bigger organic material is used as wash and transport water for the ROTAMAT-Wash Drum and is pumped to the corresponding spray nozzles of the wash drum. The remaining water (quantity corresponds to service water quantity which is added to the Coanda-Grit Washing Plant RoSF 4) is led into waste water conditioning (waste water treatment plant) or into wash water conditioning. This water cycle on the one hand considerably reduces water consumption and on the other hand results in a high separation degree regarding fine grit.

2.7 Wash water conditioning / sludge thickening

The surplus, draining water produced after the ROTAMAT-Wedge Section Screen is mechanically treated in the wash water conditioning plant, so that it can be used again as wash water in the Coanda-Grit Washing Plant RoSF 4.

Sludge (silt, fine grit, humus, ...) produced during this conditioning process is dewatered in the ROTAMAT-Sludge Thickening Plant RoS 3 until it is spadable and discharged into a container.