Updated on January 18, 2024


Created on July 21, 2020

Waterbackpack PAUL

WaterBackPack PAUL is a community water filter system.

Tested By
  • Federal Environment Agency
  • Göttingen
  • Prof. Franz-Bernd Frechen, University of Kassel
  • SGS Institut Fresenius
  • The Gambia Dept. of Water Resources
Content Partners


Product Description

WaterBackPack PAUL (Potable Aqua Unit for Living) is a 20 kg transportable small-scale water purification system designed by Prof. Dr.-Ing. F.-B. Frechen to serve several families or a small village. This product was developed primarily for humanitarian responses. The filtration capacity of the system ranges from 1,200  L/day to 5,000 L/day, and it can provide drinking water capacity for up to 400 people. The system has a gravity-driven ultrafilter membrane with the ability to remove bacteria and viruses up to 99.99% i.e. log 4.

Target SDGs

SDG 6: Clean Water and Sanitation

SDG 3: Good Health and Well-Being

Market Suggested Retail Price


Target Users (Target Impact Group)

Community, Small and Medium-sized Enterprises, Public Sector Agencies, NGOs

Distributors / Implementing Organizations

As of 2020, WaterBackPack PAUL systems have been implemented in 85 countries. In most cases the product has been donated by local or international organizations such as: Welthungerhilfe, Probono, Shanti Leprahilfe and many more. This product is also available at the online market India Mart.

Competitive Landscape

Manufacturing/Building Method

This product is mass-produced in Germany. The vertical flat sheet Ultra Filtration (UF) membranes are manufactured by Martin Membrane Systems AG, Germany; and the assembly is carried out in Kassel Disabled Workshop, Germany.

Intellectural Property Type


User Provision Model

Users can either order the product directly from Prof.Dr.-Ing. F.-B. Frechen at the Urban Water Management Department of Kassel University, purchase it from WaterBackpack Company GmbH, or through the online market India Mart.

Distributions to Date Status

3,124 PAUL units have been distributed in over 85 countries, as of January 2020.

Target use case

This product was designed for emergency settings, but it is also widely used as a permanent community-based decentralized water treatment system.

Manufacturer-specified flow rate (L/hr)

1200 L/day

Bacteria reduction

<log 4 & < log 7

Type of membrane filtration

Ultra low pressure – Ultra filtration membrane

Virus reduction

<log 4 & < log 7

Protozoa reduction


Heavy metals and/or arsenic reduction


Maximum recommended influent turbidity level (NTU)

Exact data unknown but tested up to 4,000 NTU

Effluent turbidity levels (NTU)


Material of construction

Grid plate and frame Polypropylene (PP); UF module FM10; membrane material Polyethersulfone (PES); plastic body, valves, and pipes.

Safe water storage capacity (L)


Manufacturer-specified lifetime volume (L)

10+ years

Design Specifications

WaterBackPack Paul falls under the category of a small scale water supply system (SSS), as the flow rate is around 1200 L/day. The filter facilitates the treatment of a variety of water types, such as surface water, pond water, stormwater, rainwater, and groundwater. The filtration is done by an ultra-low pressure and ultra-filtration process, integrated with an organic PES membrane. The membrane has a cake layer control and is gravity-driven. Design specifications: Weight of 20 kg Dimensions of the system 0.4 x 1.2 x 0.4 m Membrane area of 9.5 sq.meters Membrane pore size of 35 nm   The filtration unit accommodates two ways of filtration: Bucket filtration Raw water or source filtration

Product Schematics

Technical Support

There is no technical support provided and users are expected to maintain the product on their own. However, a well-articulated manual is provided as guidance for the installation and use of the product.

Replacement Components

The filter does not require any extra replacement components for operation.


10 + years

Manufacturer Specified Performance Parameters

This filter was designed to reduce bacteria by 99.999% and virus by 99.99%. Designer specified performance targets include lightweight, durable, portable, free of electricity, chemical-free, and faster in bulk filtration.

Vetted Performance Status

Testing performed by Institut Fresenius and Federal Environment Agency, Dessau/Roßlau determined this product removes 99.999% of bacteria and 99.99% of viruses.


No known safety hazards are related to this product.

Complementary Technical Systems

Raw Water Storage Tank (SWT), Filtered Water Storage Tank (FWT), Overflow Protection Valve (OPV), Single Valve (SV), water meter and metal frames or concrete blocks for the tank storage are some of the complimentary technical systems used in PAUL unit for smooth operation.

Academic Research and References

Andrade, J. A. O, 2018, Small-scale water supply system (SSS) for remote and rural areas in developing countries: A case study of the use of Ultra-Low Pressure Ultrafiltration (ULP-UF) as main technology on a decentralized small-scale water treatment plant for remote and rural communities in Colombia. Kassel University Press GmbH.

Trinh, N. D, 2018, Development of a Decentralized Drinking Water Treatment Plant Based on Membrane Technology for Rural Areas in Vietnam. Kassel University Press GmbH, Vol. 42.

Frechen et al., 2011, Long-term behaviour of a gravity-driven dead end membrane filtration unit for potable water supply in cases of disasters. Water Science and Technology: Water Supply, 11(1), pp. 39-44.

Quelch, J. A., 2016, Consumers, corporations, and public health: A case-based approach to sustainable business. Oxford University Press.

Freundeskreis-nepal.de. Available: https://www.freundeskreis-nepal.de/dokumente/upload/78698_waterbackpackpaul.pdf

“Paul Waterbackpack,” indiamart.com. Available: https://www.indiamart.com/proddetail/paul-waterbackpack-20884676491.html 

Goal 6. (n.d.). Sdgs.un.org. Available: https://sdgs.un.org/goals/goal6

“Paul Waterbackpack,” indiamart.com. Available: https://www.indiamart.com/proddetail/paul-waterbackpack-20884676491.html 

Station Manual, “The WaterBackpack Company GmbH,” Waterbackpack.org. Available: https://waterbackpack.org/download/PAUL_Station_Manual_en.pdf 

Small-scale water supply system (SSS) for remote and rural areas in .,” Google Books.

Compliance with regulations

PAUL complies with the drinking water standard of WHO 2011 for the microbial test and also complies with SPHERE Handbook (2011) for the minimum standard in water supply regarding the basic survival water need for 3 liters per capita a day (LPCD).

Evaluation methods

This product has been evaluated for bacteria (99.999%) and virus (99.99%) reductions.

Other Information

WaterBackPack PAUL received an Aqua Award in 2017 and a Green Tech Award in 2016.

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