The Equipment

A full-scale ZeeWeed treatment facility is comprised of a given number of modular components: modules, cassettes, and trains.

A module is the basic building block and the heart of a ZeeWeed system. Each module contains thousands of horizontally strung membrane fibers that have millions of microscopic pores in each strand. Water is filtered by applying a slight vacuum to the end of each fiber which draws the water through the tiny pores and into the fibers themselves. The pores form a physical barrier that allows clean water to pass through while blocking unwanted material such as suspended solids, bacteria, pathogens and certain viruses.

Modules are joined together to form a cassette, which is the smallest operable unit of the filtration system. Each cassette can have a variety of module configurations depending on the amount of water that the cassette is required to treat.

Multiple cassettes are joined to form what is known as a process train. The train is a production unit containing a number of cassettes immersed in a membrane tank. Multiple process trains form a ZeeWeed treatment plant.

Treatment Process

Feed water flows into the membrane tanks and treated water is drawn through the membranes during Production by applying a vacuum to the inside of the membrane fibers. The water removed by permeation is replaced with feed water to maintain a constant level in the tank.

The particles that are rejected by the membrane pores remain in the process tank and are periodically removed by a process called a Backwash (BW). During a backwash, filtered water reversed through the membrane fiber to dislodge any particles that may be physically lodged in the membrane fiber. Simultaneously, aeration scours any solids that are attached on the surface of the fibers.

To prevent fouling of the ZeeWeed membranes operators are required to perform regular maintenance cleans (MC). Maintenance cleaning begins by draining the membrane tank and soaking the membranes in a cleaning solution for several minutes. The solution is then drained and chemical residues are flushed from the membranes before the system resumes normal operation.

Coupling ZeeWeed to Upstream Processes

ZeeWeed membrane systems can remove particles that are larger than the pores on the membrane fiber. Contaminants that exist in dissolved form, or are smaller than the pore size, can also be removed by the membranes if they are first transformed into insoluble species or larger particles. Treatment processes commonly coupled to ZeeWeed to accomplish such conversions include enhanced coagulation and oxidation.

Typical Applications

• Tertiary Filtration
• Removal of turbidity, bacteria, viruses and cysts
• Removal of iron and manganese
• Removal of organics, color and THM precursors
• Treatment of filter backwash
• Retrofit of conventional multi-media filters
• Pretreatment for reverse osmosis
• Emergency response systems
• Mobile systems

Treatment Results

Water Treatment Results
Turbidity	< 0.05 NTU
Bacteria	> 4 log removal
Giardia Cysts	> 4 log removal
Cryptosporidium Oocysts	> 4 log removal
Virus Rejection	> 4 log **
Total Suspended Solids	Non-detect
Total Organic Carbon	50-90% removal*
Color	< 5 PCU
SDI	< 1
Wastewater Effluent (As part of a tertiary process)
TSS	Non-detect
Turbidity	< 0.05 NTU
SDI	< 1

*with coagulant addition
** Virus rejection may vary depending on application