Drapper Environmental Consultants is the Australian Licensee for this innovative technology that removes the solids from emergency sewer overflows.
WATSOL Sewer Overflow Technology
About the Watsol Sewer Comb Technology
The WATSOL Sewer Comb provides a cost-effective, high-efficiency, low-maintenance solution to remove >6mm solids from sewage during overflow events.
Using proven, unique, self-cleansing technology, captured materials are able to be returned to the sewer for transport to the treatment plant once the overflow event recedes. It can be easily retrofitted into existing manhole structures or supplied in precast/cast in-situ chambers, or designed to each specific site constraint.
As well as those mentioned above, the Watsol Sewer Comb has many advantages over other overflow technologies, such as:
It has no mechanical parts
It requires minimal cleaning or ongoing maintenance
The screening takes place below the weir, meaning backwater in the upstream sewer is avoided
Installation and maintenance time and costs are usually significantly less than mechanical screens
How does the Watsol Sewer Comb work?
The Watsol Sewer Comb uses stainless steel combs to block, filter, or screen solids from the overflowing weir nappe.
A hydrostatically-actuated ball valve helps to isolate solids in a holding chamber as water flow increases.
The combs intercept and capture the solids in the holding chamber. The combed nappe then passes through a perforated screen to a filtered water chamber before discharging to the receiving water.
As flows recede, the quick-acting ball valve releases the captured sewer solids back to the sewer chamber
Click the "BUILD MY WATSOL DRAWING" button below to develop a custom drawing to suit your site.
Click here to view the WATSOL Emergency Overflow Comb in action.
Watsol Sewer Comb FAQ
In Australia, there are separate underground drainage networks for stormwater and wastewater (sewage) in most cities. The sewer network transports the wastewater (from toilets, showers, and industrial processes) to the wastewater treatment plant, often using large pumpstations and over long distances. Stormwater is carried to the nearest waterway and released. Sometimes, the sewer pumps fail due to blockage from wet wipes, "fat bergs" or other items that shouldn't be flushed. Sometimes stormwater makes its way into the sewer network through cracked pipes, or illegal roof connections, and exceeds the capacity of the sewer pump and/or the sewer network. When this occurs, the sewer network needs to overflow at a specific point to prevent it backing up into private properties. This wet weather overflow often results in those flushed items being released to the surface creating a public health issue, and poor environmental outcomes.
Whilst it would be ideal to never have any overflows, the reality is that designing and building a sewer network to have zero overflows is prohibitively expensive. As Authorities across Australia have already discovered, even if that goal is attempted, the changing climate is quickly proving the designs inadequate, and creating enormous maintenance issues.
Not at all. The WATSOL Sewer Overflow Comb is supplied in just three parts,
1. Left hand guide rail;
2. Right hand guide rail;
3. WATSOL Assembly.
This makes installation (and removal, if ever required) very simple.
The guide rails are Dyna-bolted to the side walls of the concrete chamber (square or round), and the WATSOL assembly is lowered down the rails. Once at the desired height, the securing bolts are tightened. The entire installation process can be less than 1 hour.
The WATSOL Sewer Comb technology was designed to filter out solids greater than 5mm (eg. cotton tips, corn kernel, and larger). It captures these solids in the internal storage chamber during an overflow event. These are then released back to the sewer chamber once the overflow ends, to return to the WWTP for treatment.
Each WATSOL Sewer Comb device is custom designed to suit the specific location and constraints. Whilst there are standard models, the design flow rate and storage chamber capacity can be modified, if required. Most overflow events don't last for an extended period, and contain mostly water (instead of solids), so it is unusual for the storage chamber to completely fill. However, if this occurs, the WATSOL Comb will continue to capture solids on the comb until the water level exceeds the "relief" level and overtops the entire Assembly.
After the overflow event ends, if maintenance is required because the Comb is blocked, this can be performed from the surface with a high pressure hose. This will wash any captured solids back into the bottom of the chamber to be transported to the WWTP. It is not necessary to remove the WATSOL Sewer Comb Assembly for cleaning. This reduces WHS risks, and removes the need for Confined Space Entry.
