Veolia Water Technologies & Solutions

Greenleaf* Gravity Backwash Filter System

Low-maintenance siphon technology to control multiple granular media gravity filters

The Greenleaf Filter Control system uses low-maintenance siphon technology to control the operation of multiple granular media gravity filters. Our unique design eliminates bulky piping and valves and complex instrumentation, delivering low-cost, trouble-free performance proven in hundreds of installations.


Greenleaf Technology

Greenleaf filter control triumphs over conventional systems in a number of ways.  

Improved Plant Performance 

Greenleaf filters offer excellent stability because they are always under a positive head. All flow rate changes are gradual to eliminate the shocks and surges that can upset the filter bed. Flow is equally divided among operating filters using simple hydraulics — no mechanical flow controllers are required. 

Centralized Controls 

Centralized control economizes operation. Operators can easily select and control any filter cell from a central control center. Choose from local or remote operation and any degree of automation. Housed in free-standing modular cabinets, all controls are visible and readily accessible for maintenance and service. 

Operational Efficiency 

Our filters are designed to your specifications, so in many cases, a filter cell may be backwashed with effluent from remaining filter cells without depleting the clearwell capacity. Siphon valves that initiate and stop the flow during both the filtering and backwash cycles are easy to operate from the control center. 

Reduced Capital Costs 

The Greenleaf Filter Control offers significant savings over conventional control systems in equipment cost, site preparation, excavation, and installation. Prefabricated assemblies that require fewer components reduce field construction costs, and common wall construction with a neighboring clarifier affords additional savings.

How it Works

How the Greenleaf System Works

The Greenleaf Filter Control can be designed for plant flows of less than 1 mgd to much larger systems — and requires only two-thirds of the space needed for a conventional system operating at the same filter rate. Greenleaf’s clearwell need not be located under the filters, avoiding substantial costs in excavation and support structures, especially where poor subsurface conditions such as rock or groundwater exist.

Greeleaf Diagram


Main Advantages of Greenleaf Filter Control

The Greenleaf® filter control system can be used for drinking water filtration, tertiary wastewater & phosphorus removal, and industrial process water applications. Key advantages include 

  • Smaller footprint - Up to 30% less space versus conventional filter layouts 
  • Centralized flow splitting and backwash using simple hydraulics reduces complex piping, siphons replace large valves 
  • Self-backwashing for energy savings – eliminate or reduce the backwash pump 
  • Customizable media and underdrain type 
  • Customizable backwash procedures 
  • Customizable filtration rates