What do they cost
The Aquafilter community is on sale to Rotary Clubs and other organisations at
a cost of £250.00
What do Aquafilters do?
They remove biological contaminants (germs) and solids from water, making it normally safe to drink.
How do they work?
The heart of Aquafilters is a “membrane filter” made by a specialist supplier.
The membrane filter comprises small tubes (1 mm bore) with 0.00002 millimetre pores (holes)
in their walls.
Water flows up the tubes, and the microscopic holes in the walls allow water to pass through,
but hold back dirt, bacteria and viruses.
Sand and other coarse particles are stopped in washable pre filter, by a gauze screen with
0.12 millimetre holes in it. Finer particles pass through the screen into the membrane, where they flow up and down the inside of the tubes, keeping them free from clogging. This dirty
water is periodically flushed out of the system.
Water is fed through the system with a hand pump.
How are they used?
Water from a well, stream, pond, or lake is collected and poured into a container, usually the
box the filter came in, and in the case of the family unit also in a bucket or jerry can. The Aquafilter then pumps the water from this container, cleans it, and pours it into a clean water vessel.
This method is better than pumping directly from surface water, as it allows some dirt to settle instead of going into the filter.
Also pumping directly fro a well is not recommended, as it takes a lot of pumping effort to lift
the water, considerably reducing the flow of clean water.
Do chemicals need adding?
No. The membrane removes germs mechanically.
How is the membrane prevented from being clogged up?
This is can be done in several stages depending on the condition of the input water.----
- · Coarse particles are held back by the pre filter screen, which can be washed off.
- · Water flows along the membrane tubes in both directions when pumping, continually washing them out.
- · Clean water can be pushed backwards through the pores, freeing small particles
stuck in them.
- · It is possible for micro organisms to grow inside the tubes, blocking the pores. The Aquafilter then needs to be treated with tablets from a pot attached to the unit.
- In many applications some of these tasks are not needed.
Are there contaminants that the filters do not remove?
They do not remove dissolved substances which sometimes occur in water from deep wells. Examples are salt, calcium, or arsenic. Where it is proposed to use an Aquafilter for contaminated deep well water, the water should first be analysed to find the nature of the contamination.
What About the Appearance of the Water?
The water will be clear and free from particles. It is possible for it to be tinted by dissolved substances, for example water may be slightly green from pond weed. This does not make it unsafe to drink.
Can the clean water be stored?
Water from a public water supply is normally treated with chlorine to kill the bacteria,
which stays in the water you drink, so it can be can be stored.
Water from Aquafilters is free of chemicals, so the water cannot be stored for more than about
a day before the germs get back into it. (This is also the case with bottled water or clean well water).
What are the advantages of a membrane filter over other methods of making water safe to drink?
- · Removes all solid particles such as bacteria, viruses, cysts, and protozoa.
- · Long lasting without replacement parts.
- · Produces pure clear water free of chemicals.
- What is Special about Aquafilters?
- · The hand pump allows water on demand. You do not have to decide at breakfast what you will need for lunch!
- · There is continuous flushing of the membrane.
- · They are cost effective.
- · They are the right size for the job. The Aquafilter Community can provide water for a school or clinic, yet it is portable so that it can be carried to a locked room at night.
- · The Aquafilter Family fits neatly in a bucket, box, or adapted jerry can for instant use
by a family.
How long do Aquafilters last?
- The life of a membrane depends on the input water used. The membrane may eventually become permanently clogged, with reduced water flow. We have as yet have no evidence of this, as no unit in the field has yet shown reduced flow, in one case after two years heavy use. Membrane filters in industrial use normally last over 5 years.
Do parts need replacing?
So far the only part which has been replaced is the pump seal. This is a simple “o” ring. Spare rings are stored on the piston rod, and it is an easy task to move one to the piston.
How can know that they are working properly?
The only way the filters can fail to clean the water is if there is a break in the wall of the membrane tube which will then allow dirty water through. Fortunately the membrane tubes allow water through their walls, but not air when they are damp. This enables simple tests for air leaks to be carried out by the user. These are described in the operation manuals.
Do Aquafilters meet international standards?
There are no international standards for point of use water purification. However system providers tend to use an American EPA (environmental protection agency) guide lines. The University of Newcastle Upon Tyne has carried out a test for bacteria, and found the Aquafilter exceeds these guidelines by a large factor. Details are attached below.
Independent testing for viruses is in progress.
Where are they being Used?
To date (June24 2010) 32 Aquafilter Communities are in use in schools, clinics, and villages in Gambia, Ghana, Haiti, India, and Honduras. At this stage in the project we send them only to locations where we can get feedback, which has so far been very positive.
The Aquafilter Family has been developed more recently, and there are 10 in use in Gambia. One of these has been successfully operated for 6 months
What is the Safe Water Trust?
The Safe Water Trust is a non profit making Company by Guarantee, dedicated to developing and promoting systems for clean water at the point of use. It has evolved from and has close links with the Rotary organisation. The work is being carried out in close association with Aquabox.
What is Aquabox?
Aquabox (aquabox.org), a Rotary linked organisation, provides emergency relief in boxes.
They are partners in the Aquafilter project, and distribute Aquafilter Community units on their standard boxes for emergency relief. They are planning to assemble Aquafilter Family units,
and will incorporate them in the boxes to replace the chlorine tablets and carbon filters.
SPECIFICATIONS
|
Membrane property
|
Aquafilter
Community
|
Aquafilter
Family
|
|
Inner tube diameter
|
0.9 mm
|
0.9 mm
|
|
Molecular weight cut off
Equivalent pore size
|
100K
0.02 microns
|
100K
0.02 microns
|
|
Applicable pH
|
2 to 12
|
2 to 12
|
|
Applicable temperature
|
5 to 45 deg C
|
5 to 45 deg C
|
|
Tube material
|
PVC
|
PVC
|
|
|
|
|
|
Washing with sodium
Hypochlorite (bleach).
Maximum free chlorine
|
100 ppm
|
100 ppm
|
|
Washing with NADCC tablets
Maximum free chlorine
|
200 ppm
|
200 ppm
|
|
Working pressure
|
1 to 3 bar
|
1 to 3 bar
|
|
Breaking pressure
|
13 bar
|
13 bar
|
|
|
|
Filter Unit
|
Aquafilter
Community
|
Aquafilter
Family
|
|
Output
|
300 litres/hour
|
1 litre/minute
|
|
Dimensions
|
260x260x500mm
|
100x130x500
|
|
Weight
|
12 kg
|
1.5 kg
|
TESTS 16 April 2010
Laboratory evaluation of the performance of an Aquadyne Membrane Filtration Unit.
Aim
To evaluate the filtration efficiency of an Aquadyne Membrane Filtration Unit using a water sample contaminated with Escherichia coli.
Method
A 10 L sample of ¼ strength Ringers solution at 22 C was contaminated with E. coli, from a batch grown culture in nutrient broth, to give a final concentration of more than 109 cell per 100 ml. This was subjected to filtration through an Aquadyne hand-pumped membrane filtration unit and samples of filtrate collected after at least 6 L of filtrate had been produced. Duplicate samples of filtrate and duplicate samples of the unfiltered contaminated water were subjected to serial dilutions and counted by the Membrane Filtration Method using membrane lauryl sulphate broth medium, and incubated for 18h at 44C before counting.
Results
Table 1 shows that counts of E. coli in the contaminated water were extremely high, more than 109 per 100 ml, a concentration which is far greater than that of many contaminated surface waters (104 to 106 /100 ml, personal communication of the author).
After filtration, neither of the filtered samples showed any evidence of E. coli, giving a minimum removal efficiency of
9-log removal.
Conclusion
On the evidence of the tests conducted on this Aquadyne unit, the high removal efficiency of E. coli indicates that the filter should be capable of removing very substantial quantities of pathogenic microorganisms present in
untreated water supplies.
Table 1. Enumeration of E. coli in contaminated water before and after filtration through an Aquafilter membrane filter unit.
|
Contaminated Water
|
AFC6
|
AFC5
|
AFC4
|
AFC3
|
AFC1
|
AFC2
|
|
Sample Dilution
|
10-8
|
10-8
|
10-7
|
10-7
|
10-6
|
10-6
|
|
CFU on plate
|
8
|
8
|
101
|
109
|
>201
|
>201
|
|
E-Coli CFU/ 100ml
|
8.00E+08
|
8.00E+08
|
1.01E+09
|
1.09E+09
|
TNTC
|
TNTC
|
|
Contaminated Water
Average
CFU/100ml
|
8.00E+08
|
1.05E+09
|
TNTC
|
|
|
|
|
|
|
|
|
Filtrate
(treated water)
|
AF1
|
AF2
|
|
|
|
|
|
Sample Dilution
|
100
|
100
|
|
|
|
|
|
CFU on plate
|
0
|
0
|
|
|
|
|
|
E-Coli CFU/ 100ml
|
< 1
|
<1
|
|
|
|
|
|
Filtrate
Average
CFU/100nl
|
<1
|
|
|
|
|
|
|
|
|
|
|
|
Removal Efficiency
|
Log Reduction
|
|
|
|
|
|
Compare (AFC3 , AFC4) with (AF1, AF2)
|
>9 Log Removal
|
|
|
|
|
TNTC = too numerous to count
CFU = colony forming units
Dr Paul Sallis
Senior Lecturer in Environmental Engineering School of Civil
Engineering and Geosciences
Newcastle University Cassie Building
Claremont Road Newcastle upon Tyne
NE1 7RU
p.j.sallis@ncl.ac.uk
