Membrane filtration modules Alfa Laval
17.03.2015

According to the UN, almost one-fifth of the world’s population lives in areas experiencing water scarcity. By 2025, it is estimated that two-thirds will experience water shortages. Yet at the same time, vast amounts of wastewater are generated daily, most of which is dumped into rivers and seas without adequate treatment, creating health and environmental hazards.

So increased focus is being put on water reclamation and efficient wastewater treatment, with ever-stricter regulations. “More and more people are realising that wastewater is a valuable resource,” says Mai Møllekær, Managing Director of Alfa Laval Ashbrook Simon-Hartley. “With the right solution, reusing wastewater is environmentally, socially and economically beneficial. Alfa Laval offers two filtration methods that help turn municipal and industrial wastewater into clean water.”
MEMBRANE BIOREACTORS (MBR) are an increasingly common solution for producing exceptionally clean effluent from biological wastewater treatment processes. They treat over 4 million cubic metres of wastewater every day – a figure that is expected to triple by 2018

“Alfa Laval has developed a unique MBR technology, based on membrane filtration modules incorporating patented hollow sheet technology. Compared to other MBR solutions it offers improved safety, simplicity of operation, plus low operation and maintenance costs,” says Thomas Møller, Segment Manager for Water and Waste Treatment at Alfa Laval. “Our MBR solution proves its value every day at numerous installations worldwide. Several customers specifically chose this because of its exceptionally clean final effluent, which they can reuse.”

1.    General description
The MFM (Membrane Filtration Module) from Alfa Laval is designed to boost efficiency and reduce operating costs for the filtration of biologically treated waste water of both industrial and municipal origin. This membrane filtration solution for membrane bioreactors (MBR) combines the best features from flat sheet and hollow fibre membrane technologies into the unique hollow sheet membrane design offered by Alfa Laval. Thanks to combining two technologies into one, Alfa Laval achieved many unique features of their modules, such as:
  • Low energy consumption
  • Fully gravity operated membrane at ultra low TMP, giving ground-breaking simplicity for the total MBR installation
  • Exceptionally high packing density - 1 m2 membrane for 1 m2 of factory area
  • Design that is much less prone to fouling than conventional hollow fibre and flat sheet membrane filtration configurations
  • High cleaning efficiency by circulating cleaning liquid through the Membrane Filtration Module – long intervals between cleaning
  • Membrane materials that are highly resistant to acids, caustic substances and oxidation, for extended service life
  • Gravity-driven MBR module – simple, reliable and cost-efficient solution

The unique design feature of the gravity operated Alfa Laval Membrane Filtration Module is that it operates with an exceptionally low transmembrane pressure (TMP) – up to 10 times lower than today’s technology - across the entire surface of the membrane. This means that the mixed liquor is not squeezed against the membrane surface.

A unique Alfa Laval design ensures that permeate (cleaned effluent) is drained from the entire surface of the membrane and that it emerges all the way round the edges, exiting through connectors at the top of the unit. This means the pressure drop over the membrane is close to zero and there are no dead spots on the membrane itself. This extremely low TMP means the membranes are significantly less prone to fouling, resulting in a longer lifetime and extended operating periods between cleaning.

Ultralow TMP The unique design feature of the gravity operated Alfa Laval Membrane Filtration Module is that it operates with an exceptionally low transmembrane pressure (TMP) – up to 10 times lower than today’s technology - across the entire surface of the membrane. This means that the mixed liquor is not squeezed against the membrane surface which reduces fouling and consequently the need for cleaning, resulting in a longer service life between replacements.

And when cleaning is eventually needed, it is easy to deal with the entire membrane surface effectively using cleaning sequences that include relaxation, back pulse, Cleaning In Place (CIP) by circulation.

There are many specific benefits resulting from Alfa Laval membrane filtration modules for end users, subcontractors and companies using Alfa Laval modules as components of their devices (see Table 1).
 

Fig. 2. Flat sheet module + hollow-fibre module = Alfa Laval Hollow-sheet membrane filtration module

Tab. 1. End-user benefits resulting from Alfa Laval membrane filtration module
Solution Advantages and benefits
Utilization of the full membrane surface Less fouling
Ultra low TMP – up to 10 times lower than hollow fibre and flat sheet membranes Less fouling
Robust module design Long module lifetime
Gravity-operated MBR Simple system (fewer pumps and Simple control system needed)
Stackable design Better utilization of scouring air – ma king it energy-efficient
Multiple cleaning methods – back flush, circulation and soaking Easy cleaning
Strong PVDF membrane Suitable for multiple applications
Compact design High packing density
 

Fig. 3. Element of membrane filtration module


Schwander Polska®
Since 2013 membrane filtration modules manufactured by Alfa Laval are distributed by Schwander Polska® company. Schwander Polska® has extensive knowledge and broad experience in the field of design and construction of wastewater treatment plants based on MBR (Membrane Biological Reactor) technology.  

MBR wastewater treatment plants are not only perfect for municipal and industrial wastewater treatment but also for one-family residential units, multi-family residential, commercial buildings such as hotels, inns, petrol stations, schools or housing estates.
 
 

Fig. 4. Stanisław Malinowski, CEO at Schwander Polska® with Alfa Laval Certificate



Fig. 5. Wastewater treatment plant in Piątkowa
  1. Examples of wastewater treatment plants engineered by Schwander Polska® using membrane filtration modules manufactured by Alfa Laval
 
2.1. Municipal wastewater treatment plant in Piątkowa
Wastewater treatment plant in Piątkowa is located at the plot bordering with a school playground in Piątkowa. Treated sewage is discharged to the Łętówka Stream.
 
2.2. Extension and reconstruction of the wastewater treatment plant in Mała Wieś
Wastewater treatment plant is located at the site of existing wastewater treatment plant, which was deactivated after construction of MBR wastewater treatment plant. Treated sewage is discharged to the Dunajec River.
Two projects are being executed right now:
  • Extension and reconstruction ofwastewater treatment plant in Chełmiec
  • Extension and reconstruction ofwastewater treatment plant in Wielogłowy
 
In 2015 and 2016 Schwander Polska® will execute another 6 projects using membrane filtration modules manufactured by Alfa Laval in Poland and Slovakia.
The article features fragments of „Wastewater: an untapped water resource”, Alfa Laval Here Magazine, author: Nic Townsend and commercial materials of Schwander Polska® and Alfa Laval.

Link to electronic edition: http://seidel-przywecki.pl/pl/p/Forum-Eksploatatora-nr-78-e-wydanie-32015-/505

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