Water & Wastewater Solution
Developing innovative solutions and capabilities to secure a sustainable supply of water.
Developing innovative solutions and capabilities to secure a sustainable supply of water.
At Horsol Switz Engineering, we provide the expertise required in Material Procurement, Pre-Treatment Systems, SWRO Process Islands and Post-Treatment Systems for desalination plants.
DAF is the process of removing suspended solids, oils and other contaminants via the use of air bubble flotation. Air is dissolved into water, mixed with the waste stream. Air bubbles form and attach themselves to contaminants causing them to surface. The contaminants can then be mechanically skimmed and removed from the tank.
DAF with mechanical sludge scraper
DAFF with hydraulic sludge decanting
Mechanical scraper - the floated sludge is removed by a carbon steel-rubber lined mechanical scraper running at low rpm. The scraper has twin spiral wound blades along the shaft that will scoop the sludge on a specially designed plate towards the sludge channel and also ensure that sludge being scooped is not in a fine floated form that is likely to break off, a frequent occurrence when a travelling bridge scraper is used.
The scrapper is driven by a VSD motor to provide adjustment to the rotational speed and can be operated intermittently or continuously to optimise sludge removal operation. Sludge with 1% - 4% dry solids content can be expected with a mechanical scraper.
A dual media filter/multi-media filter is primarily used for the removal of turbidity and suspended solids as small as 10-20 microns. Dual media filters provide very efficient particle removal under a high filtration rate. Inside a sand-anthracite filter is a layered bed of filter media. The bed is graded from bottom to top as follows:
Having the filter media graded this way enables the sand anthracite filter to run for a longer time before a backwash is necessary. A sand anthracite filter or multi-media filter consists of 2 main parts:
Internally, the dual media filter is fitted with an inlet distributor and a bottom collecting system. Externally, the system is fitted with frontal pipe work and isolation valves. Sand is used to remove the suspended particles and anthracite is used to remove colour and make the water fit for various applications. Gravels and pebbles are provided to support both of the media. Periodically, the sand-anthracite filter will need to be backwashed, which is done by reversing the water flow through the sand-anthracite filter.