The multinational company Nestlé has a factory in Senegal with 400 workers where produces the popular Maggi cubes. These workers need to be provided with potable water to ensure their water needs and to guaranteeoptimal and safe working conditions. For this reason Nestlé carries out periodic analysis of chlorine level in all watersupply network and in its 70 water taps distributed throughout the factory.
Water disinfection in Nestlé factory in Senegal
Senegal's case study
Context
Once these analysis have been done, it is shown that the supply network which gives water to the factory has highly variable levels of chlorine, with oscillations from very high ones to almost nonexistent.
Given this situation, and after trying with a dosing proportional to the water inlet that caused over-chlorination, they realize that the only way to get adequate levels of chlorine in the factory is through manual corrections, depending on the level of chlorine in the inlet.
It is then when Nestlé trusts in Aqua’Tec to recommend a solution to this problem.
Aqua'Tec Solution
At Nestlé factory there are two water storage tanks: one of 250 m3, which also feeds the fire circuit, and one of 150 m3 from which the water is distributed inside the location. With the existence of these two tanks, it is proposed to make a pretreatment in the first one and a final treatment in the second, from where the water is distributed to all 70 consumption points.
Considering the variation in chlorine levels, the pretreatment is projected with an initial reading of chlorine in the input through a Redox measuring equipment, combined with a dosing proportional to the water supply flow. Thus, when the levels of chlorine in water supply are too high, Redox controller stops the proportional dosingautomatically.
In the treatment tank there a 40m3/h recirculation system is installed (flow enough to maintain the desired value of free chlorine without oscillations, according to the existent water consumption) on which chlorine reading and correction are made to set it at 0,3 ppm, therefore complying with Nestlé standards.
Location
- Nestlé factory, Senegal
Key Points
- Initial difficulty to set free chlorine due to variability in the level of water supply
- Desired chlorine level: 0,30 ppm
- Automatic activation / disabling of proportional dosing during the pretreatment stage, depending on the level of chlorine in the water inlet
Used equipment
Pretreatment
- WTRpro-RX: Redox measuring equipment
- Redox sensor
- Dositec-Q 2.5l/h: Proportional electromagnetic dosing pump
- Flow Meter
Treatment
- WTRpro Cl-pH panel: pH and chlorine control equipment, with free chlorine sensors, pH and dosing pumps control
- Dositec mA 2.5 l/h: Electromagnetic dosing with analog control for hypochlorite
- Mixer with PE coating
- Holding tank
