Wss-Homogenizer
FLOW HOMOGENIZER
THE ISSUE
In the usual sizing process of a lamellar settling tank, we always start from a basic error, considering the ascent speed through the lamellar package as homogeneous and as a function only of the flow rate and the available passage surface. This is an error for the following reasons:
- The effluent inlets are localized and of limited section.
- Generally horizontal, forcing a change of direction.
- It is not possible to control the inertia of the water.
- Even in inputs with a large flow section available, the effluent will tend to generate fluid veins with speeds much higher than the average input speeds considered.
- Affecting the flow of the support profiles acting as deflectors.
- The inertias are conserved in the upper zone of the lamellar package.
CONSECUENCES
The consequences of all this are:
- Preferential flow in certain areas of the lamellar package depending on the mentioned inertias.
- Very high ascending speeds in these areas, depending on the tank geometry and effluent inlets, it is usual to find values of up to 400% of the nominal speed, even higher.
- As compensation, many zones will work with zero or negative speeds of up to –200%.
- Between 400% and –200% the rest of the speeds will be distributed. All the zones with higher speed than the nominal one will present a lower efficiency and all the zones with lower speed will suppose a loss of effective surface.
- The support grid generates high velocity zones in the upstream channels according to the flow direction and negative velocities in the rear channels.
- High speed zones will allow the passage of large amounts of solids.
- Given the homogeneity of the evacuation and the mentioned zones of zero or negative velocities, horizontal flows will be produced through the upper zone of the lamellar package.
- During these horizontal trajectories the sludge that crossed the lamellar package in the high speed zones will settle generating fouling.
- It is the main factor of loss of efficiency and fouling.
THE SOLUTION
Wss-Homogenizer is a system developed and patented by WssDynamics® that allows the total homogenization or balance of the flow through the entire installed lamellar surface. That is, the ascent speeds will be practically the same in each and every one of the installed lamellar modules, regardless of their location in the tank.
This unique behaviour of the Wss-Homogenizer installed together with the WssDynamics® lamellar modules, allows us to have a global lamellar settling system with an operation very close to the conceptual values of the technology.
