ASP - Wastewater treatment and sludge dewatering process
The ASP (Automated Sludge Press) can work in two modes – sludge dewatering and wastewater treatment. Both are completely automated processes and perform solid separation resulting in dry solids.
The diagram shows the process – for the wastewater there is an added step of filtering out the water.
Detailed explanation below, for a visual presentation – Automated Sludge Press (ASP) in process video.
The base of the wedge screen is blocked by the lower sliding door and sealing membrane.
Sludge is pumped into the mechanical Flocculator where it mixes with flocculent. The flocculated slurry then enters the void between the inner screen and the pressing diaphragm, the excess filtrate is percolated through the screen slots, while the thickened sludge (about 10% DS), is retained internally. The semi dry sludge is accumulated on the bottom of the cylindrical screen and settles upward.
Relevant to wastewater mode, the wastewater is filtered through the ASP screen, and the solids retained are simultaneously thickened and later dewatered by the pressing operation.
For dewatering mode, the sludge is thickened while filling (merge with filling).
When the void is full, a sensor signal stops the filling/thickening sequence and the pressing sequence is started, the flexible membrane is inflated while pushing the solids against the screen surface by a radial force, which is the fastest and most efficient way to dewater slurries.
The excess fluids is drained out externally, this step is time controlled for few minutes with both pressing and pulse pressing steps controlled by the PLC program..
Unloading / Sludge downloading
At the end of the pressing sequence the drain tray swings away, the lower door membrane deflates and the door retracts.
The scraper carriage is then activated cycling up and down the internal surface of the wedge screen dislodging the sludge cake allowing it to fall freely to the collection container below.
After the scraping sequence has been completed the drain tray swings back around ready to capture the cleaning residue.
With the use of both water and air the screen is automatically backwashed by a ring of spray heads moving up and down the outside surface forcing any remaining sludge caught in the screen back into the void and down into the drain tray.
A new filing sequence is started.
The on board PLC enables friendly and smart parameters in order to optimize the press operation.