New ZENON MBR Cassette

ZENON have introduced the new ZW500d cassette that has set new standards in membrane treatment for wastewater and potable water treatment. The cassette has improved packing density and educed operational costs. It adds a further dimension to the ZENON family of membranes.

New ZENON MBR Cassette

A ZeeWeed® 500 based water treatment process involves producing treated water by drawing the water through the membrane fibers in an “outside – in” flow path under a slight vacuum. ZeeWeed® membrane fibers are installed directly in the tank of water to be filtered and replace both the clarifier and the granular media filters of conventional drinking water or wastewater treatment systems.

The ZeeWeed® membrane has been approved by the National Sanitation Foundation (NSF) as an ultrafilter (UF). The outside surface of the fiber is a highly water permeable polymeric membrane and will remove biological contaminants, particulates and colloidal species from water, including:



Cysts and Oocysts

Fe and Mn

ZeeWeed® 500 Target Applications

The membranes are versatile and can be used in both water treatment and wastewater treatment applications. They are intended for applications with medium to high suspended solids concentrations. The target applications have been divided into two groups:

1) Water Treatment (Direct Filtration):

Municipal drinking water treatment: membrane filtration of surface or ground water to produce potable water. Membrane filtration can also be combined with:

enhanced coagulation (for organics and arsenic removal)

chemical oxidation (for iron and manganese removal)

powdered activated carbon addition (for taste and odour removal) to achieve particular effluent requirements

Reverse osmosis (RO) pretreatment: membrane filtration of surface water or ground water to reduce SDI of RO feed

Tertiary treatment: membrane filtration of secondary effluent from wastewater processes for recycle/reuse or simply to ensure optimum quality effluent is continuously discharged

2) Wastewater Treatment (Membrane Bioreactor Systems):

Municipal/industrial wastewater treatment: combining membrane filtration with a conventional activated sludge process to treat a variety of municipal or industrial wastewaters.

Shipboard wastewater treatment: for wastewater treatment on a variety of ocean-going vessels.

Commercial or private development wastewater treatment: for property owners who wish to treat their wastewater on the premises (typically because they cannot be connected to a municipal sewer because of capacity limitations or distance).

In wastewater treatment, the combination of membrane filtration and biological treatment is otherwise known as “membrane bioreactors” and is offered by ZENON as the ZeeWeed® MBR Membrane Bioreactor process. In this process, the ZeeWeed® membrane serves to replace the clarifier in a wastewater treatment system. The benefits of substituting a ZeeWeed® membrane for the clarifier are significant and include:

Tertiary quality effluent is produced without extra equipment since the membrane is an absolute barrier to suspended and colloidal solids

Capacity of existing wastewater treatment plants can be increased without requiring more tanks as the MLSS in the activated sludge tank can be increased to 10,000 – 12,000 mg/l

Nutrient removal is improved because of the effective retention of suspended solids by the membrane

ZeeWeed® 500 Membrane Fiber

The membrane is a reinforced fiber with a nominal pore size of 0.04 µm.

ZeeWeed® 500 Module

The membrane module is the building block of the system. An individual membrane module is the smallest replaceable unit within a ZeeWeed® filtration system. The ZeeWeed® 500 membrane module consists of hundreds of membrane fibres oriented vertically between two headers. The hollow fibres are slightly longer than the distance between the top and bottom headers and this allows them to move when aerated. It is the air that bubbles up between the fibers that scours the fibers and continuously removes solids from the surface of the membrane.

ZeeWeed® 500 Cassette

A cassette is the smallest operable unit of the filtration system. Standard cassette configurations are available ranging in size from 1 -36 modules.

ZeeWeed® 500 System Design

A system typically consists of a 2 or more parallel trains. Each train consists of:

a process pump

automatic valves


The following components are generally required in a system and can either be dedicated to a specific train or shared amongst trains:

a tank (into which cassettes are immersed)

metering pumps (for chemical addition)

membrane blowers (to provide air for scouring the membranes)

reject or sludge pump

vacuum pump (for entrained air removal)

“clean-in-place” pumps

backpulse or wash tank

control system

Other components may or may not be needed depending on the design or application:

strainers (for pre-screening the feedwater)

process blowers (biological treatment systems only)

feed pumps


sludge recirculation pumps

cassette removal hoist or other mechanism

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