Wedge wire screens do not reflect a system that is specifically made for seawater intake. They represent a reactive solution to a problem that was underway. They are operation and maintenance intensive. They have to be frequently backwashed and air purged to push away the impinging marine life and debris. The backwashed and purged material returns to the screens along with fresh supplies soon after the backwash pumps and air purging compressors are turned off. The backwashed and purged material is not drained away but all of it or a large part of it would keep coming back and increase the frequency of backwash and air purge.
The InvisiHead has proved to be more cost effective. It is a well engineered proactive intake system which actively addresses operation and environmental requirements compared to the highly reactive wedge-wire screen intake head systems. The overall performance of the Elmosa Seawater Intake System is higher than any other system operating in the water intake industry. The system entirely utilizes the natural process in its entire operation from the start to the end – from the point where the first water molecule at the offshore end of the system is gently drawn to the InvisiHead and smoothly guided through all the way to the pump intake at the onshore NatSep intake basin.
In contrast, the wedge-wire screen intake head employs several reactive layers of measures needed to keep the system in operation. Wedge-wire screens are not a dedicated seawater intake head system like the InvisiHead but modified well screens. They have to be supported by a costly clean up system to convert them into operational seawater intake heads.