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FAQ

 

QUESTION:

1) What are the main elements in the raw waters coming from both Surface water & Groundwater, this system can treat?   And what is the log removal for each ?
In other words, we are here in Beheira governorate, Egypt have algae, ammonia and organic matter in our Surface water while we have Fe, Mn, TDS, Nitrite and Arsenic with high unacceptable contents. What is the log removal for each by your treatment system?

ANSWER:
Regarding all the above mentioned elements coming from raw waters (that is to say algae and organic matter), they will be retained by the filter. If the iron and manganese are in a form of precipitated elements, it is supposed to be retained by the filter too. As for nitrites, arsenic and ammonia, we have no experiences until now.  But a pilot plant would allow precisely determine the effectiveness of treatment and it will strongly depend on the concentration of these elements. 


QUESTION
 :
2) What is the meaning of the water turbidity unit, UTF? and what its relation to the turbidity unit, NTU?

ANSWER
:
UTF unit is "old" name of NFU (Formazine Nephelometric Unit).
For information, the NTU (Nephelometric Turbidity Unit) up to 20 NFU, 1 NFU = 1 NTU.
Upper than this, 1NFU = 0.6 NTU.
But what is important is that our Filter can handle water up to approx. NFU 150 (90 NTU) and the finished product is close to 1, when the installation is working properly.


QUESTION
:
3) What are the dimensions of the settling tank?

ANSWER
:
The purpose of the decanter is mainly to allow the flocculating product to act by increasing the time between injection and filter. In Cameroon, for example, our system installation is operating without a decanter. We only increased the diameter of the pipes between the injection of the flocculating product and the filter to lengthen the contact time. On the other installation, the water purifying system treats rainwater in majority, and so the decanter is 300 litres.


QUESTION
:
4) It is mentioned that no chemicals used at this system on contrary to what is shown at the schematic drawing of this system, there is aflocculation unit and chlorination unit?!

ANSWER
:
We actually use chlorine only for the disinfection of the filtering mass during washing against the current. Regarding the flocculating product, of course, it helps the settling of large particles in suspension, but it is primarily used to agglomerate the small particles and more important to facilitate their retention by the filter. We do not throughout chlorine in the drinking water container before it is drunk by the beneficiaries. In that way, we do not use chemicals as it is sometimes advices to household in some countries to poor some drops of chlorine in the water.


QUESTION
:
5) How and where is the backwash water drained?

ANSWER
:
Let’s see our schematic drawing attached hereto (as for an example).
As for example of performance, we will send you  also results (our engineer is on vacations) of water analysis performed by the Laboratory of the Public water operator of Geneva and also bacteriological results made in our operating plant in Africaso that you may evaluate yourself  the efficacy of our water purifying system. We wish also to mention that our water purifying system does not compete with the official ones of Geneva and we can not get exactly the same results! But as we mentioned, the water quality would be respecting the WHO standards and Swiss standards.


QUESTION:
6) What is flocculation?

ANSWER:
Flocculation is, in the field of chemistry, a process where colloids come out of suspension in the form of floc or flakes. The action differs from precipitation in that, prior to flocculation, colloids are merely suspended in a liquid and not actually dissolved in a solution. In the flocculated system there is no formation of a cake since all the flocs are in the suspension.
Flocculation and sedimentation are widely employed in the purification of drinking water as well as sewage treatment, stormwater treatment and treatment of other industrial wastewater streams.


QUESTION:
7) What are the Flocculants or Floculating agents?

ANSWER:

Particles finer than 0.1 µm (10
-7m) in water remain continuously in motion due to electrostatic charge (often negative) which causes them to repel each other. Once their electrostatic charge is neutralized by the use of coagulant chemical, the finer particles start to collide and agglomerate (combine together) under the influence of Van der Waals's forces. These larger and heavier particles are called flocs.
Flocculants, or flocculating agents (also known as flocking agents), are chemicals that promote flocculation by causing colloids and other suspended particles in liquids to aggregate, forming a floc. Flocculants are used in water treatment processes to improve the sedimentation or filterability of small particles. For example, a flocculant may be used in swimming pool or drinking water filtration to aid removal of microscopic particles which would otherwise cause the water to be turbid (cloudy) and which would be difficult or impossible to remove by filtration alone.






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