Technological Features
Function
The AQQA®-system is a submerged ultrafiltration system of the next generation, which combines proven and new, unique features.
The filter is submerged into the untreated water. With a gentle pressure the water is sucked into the filter, leaving all particles and bacteria on the outer surface of the membrane.
An optimized flow of air bubbles and water cares for a constant cleaning effect with high shearing forces on the membrane surface. This cleaning effect alone can keep the filter clean for up to one year.
The AQQA®-filter is the first filter with solid plates that can be back-flushed by reversing the flow and pressing a cleaning liquid into the filter. By doing this, all pores are kept open and the filter can operate sustainable with a much higher output.
In normal operation, the filter remains in the water and does not have to be removed from the tank, as it was the case with filters of the first generation.
Applications:
Treatment and reuse of waste water, municipal and industrial
Reuse of Greywater
Treatment of cow or pig manure
Sludge thickening
Treatment of surface water for production, irrigation or drinking water applications
Pretreatment of water for desalination plants
Design
The AQQA®-filter is made up of stacks of filter plates. These stacks are preassembled and the filter plates are connected with a snap-on system. A stack can be easily lifted out of a frame and filter single filter plates can be removed within minutes.
The stack builds an extremely robust unit, which ensures straight plates and a uniform gap of 6 mm. No matter how tough the operating conditions are, this setup does not change its geometry. Together with the optimized aeration system, this system is not prone to clogging and can be operated under very harsh conditions. The complete unit is submerged into the mixed liquor, either directly into the aeration tank or in an externally placed membrane tank.
In normal operation the filtrate is removed with a self-priming pump (PIC3, P01). A fraction of the filtrate is stored in the filtrate tank and can be used for the cleaning of the filters. The AQQA®-system is back-flushable with 350 mbar (5 psi). It combines the robustness of a plate system with the advantage of easy cleaning by pumping a cleaning liquid into the filter. PIC 3. shows a possible setup for the operation.
The AQQA®-system is designed as a modular construction system. Three basic blocks are available. AQQA®xx (xx stands for 1,5 up to 8 m²), AQQA®25 (25, 50, 75 m²) and AQQA®80 (80, 160 and 240 m²). Always one aeration element (light green) is combined with the resp. number of basic filter blocks.
With a standardized mounting system the AQQA®-filter can easily be installed into an existing tank. The system hangs on two bars, that are supported with brackets at the wall. The system is secured against swinging and buoyancy.
Features of the AQQA® System
Feature #1: The membrane of the AQQA®-system is fixed to the plate not only at the edge, but with fixation points, that are distributed evenly over the complete surface. This leads to a number of advantages. The membrane can be back-flushed and does not tear. While the membrane is relaxed (no filtration pressure), the aeration can be kept running and the membrane does not flutter. The membrane is made of 2 layers, the active filtration layer and an extremely robust backing, that is bonded to the filter frame with a molten polyolefin.
Advantages for the operator:
The filter membrane is anchored to the plate and cannot tear.
The hygienic safety is significantly higher, than filters made with conventional welding technologies.
With the unique fixation point technology, water can flow through the filter plate in two directions. In filtration mode the water flows from the outside to the inside. The untreated water is filtrated through the membrane, which retains bacteria, virus and particles. The filtrate can flow to the outlet with practically no pressure loss.
In backflushing mode the flow direction is reversed and filtrate flows from the inside to the outside, removing the dirt layer and particles. Adding a chemical to the backflush (chemical enhanced backflush) allows for an efficient cleaning of the membrane, while the filter remains in place. This makes maintenance a lot easier and effective.
For cleaning filtrate is used, that has been stored in the filtrate tank. It is pumped into the filter with a backflush pump. Optional the filtration pump can be reversed and the filtrate is pumped into the filter with the filtration pump. Simultaneously, a cleaning chemical is added with a dosing pump. This process takes approx. 40 minutes. In most installations, this procedure is carried out every two to four weeks.
Advantages for the Operator:
A robust filter plate with full backflush capability up to 350 mbar. Replacement of existing hollow fiber systems without changes to the system.
The cleaning of the filter can be done in the membrane tank. It is not necessary to remove the filter from the tank. Cleaning cycles can be automated.
Feature #2: The filter plates are rigid and do not bend. This cares for a defined gap between the plates, which guarantees optimised flow conditions. It is not possible, that plates or fibers stick together or form bundles of sludge, hairs and filter elements.
An examination carried out by the Technical University Berlin documents this situation very impressively:
Advantages for the Operator:
The AQQA®-filter does not plug with fibers, which ensures the operational safety and availability
The mechanical cleaning of the filter plates with air bubbles is much more efficient. This minimizes the use of cleaning chemicals and the energy input is reduced.
The filter plates do not stick together like known from to date systems. That is why 100% of the membrane surface of the AQQA®-filters is operating and not just partitions.
Feature #3: By the use of a membrane with a very high porosity (pores per sq.ft) and the filtrate removal almost without pressure loss, the permeability of the membrane is high when new and stays high. The output is up to 100% higher, than with known systems.
Advantage for the Operator:
The total cost for the system (CAPEX) is lower and it needs less space.
Feature #4: The installation of the system can be easily accomplished into new plants, but also into existing plants due to the modular design and the well thought out installation device. This enables the retrofit of plants that are equipped with filters of other manufacturers.
Advantage for the Operator:
Retrofit with most modern filtration technology at lowest cost. No complex and time consuming alteration.
The AQQA® Filter
The AQQA® Filter belongs to the group of so-called submerged “ultrafiltration systems.” These systems are characterized by the fact that they are immersed in the polluted water.
The water is filtered by gravity alone or with a slight negative pressure. The filter plates are cleaned at regular intervals either by air bubbles or by chemical cleaning. This technology has developed since the mid-1990s and through our proprietary improvements are able to be produced in large quantities in a portable unit and supplanted int MBRs.
In the drinking water sector, submerged ultrafiltration is used for the treatment of surface water and for pre-filtration of seawater for desalination with reverse osmosis.
This technology makes it seamless for a variety of applications:
Large municipal sewage treatment plants
Small municipal wastewater treatment plants
On Cruise Ships
In industrial sewage treatment plants
In containerized sewage treatment plants, such as those used for workers’ camps in remote regions
Specification Sheet
Submerged ultrafiltration system for the use in municipal or industrial wastewater.
Plate system with rigid plates made of PP and a uniform gap of 6 mm. Membranes cannot touch each other and stick together. No development of filter cake between the plates due to constant flow velocities.
Single filter plates can be exchanged.
The membrane is fixed to the base plate not only at the edge, but at numerous fixation points, that are evenly distributed over the complete filtration surface. Max. backflush pressure 350 mbar. Max. filtration pressure 500 mbar. Membrane cannot move at different differential pressures. During the relaxation phase, the membrane cannot flutter while the rising air bubbles create areas of suction.
Permeability of a plate > 1000 l/m².h.bar, measured with tap water at 20°C, typical flux in municipal wastewater applications > 25 l/m²h (14,5 g/ft².d). Filtrate output does not depend on the MLSS concentration.
Retention rate for bacteria > 99,9999% (tested with E-coli and GTW1 according to NSFP231).
PES membrane, highly and permanently hydrophilic. pH resistant 1-12, chlorine resistance 500.000 ppmh. Membrane can dry after usage. Nominal pore size < 0,04 μm. Retention of > 90% of particles with a pore size > 0,04 μm.
Max. operating temperature 50°C, 122° F
Each filter leak tested with pressurized air at 0,3 bar, before it leaves the factory.
Plate aeration system with uniform bubble distribution across the complete membrane area. Water enters into the upstream flow channel above the air diffusors to optimize the flow velocity. Medium sized air bubbles (approx. 8 mm) for maximum shearing forces on the membrane surface.
Frame made of stainless steel 1.4301 (SS304), optional 1.4571 (SS316). Modular blocks that can be stacked on top of the aeration unit.
Standardized installation device with two rectangular bars that are supported with brackets at the membrane tank wall. Easy lift out and installation without emptying the membrane tank.
Necessary pre-screening 2 mm punch hole (or mesh wire). For different screening options please contact Weise Water.
Mixed Liquor temperature 5° - 50°, MLSS concentration < 20.000 mg/l, FOG (fats, oil and grease) < 150 mg/l (emulsified), no free oil, less than 10 mg/L of mineral or non-biodegradable oil.