Many UAE factory managers are told their water is "soft because it is desalinated", then find white crust on a pasteuriser plate, a cooling tower fill clogged with deposits or spots on every PET bottle leaving the washer. Both things can be true. The public supply in most emirates starts as desalinated seawater, yet scale still builds inside a food or drink plant because heat, evaporation and storage concentrate the minerals that are there.
This article is for engineering, maintenance and QA teams in food and beverage plants across the Emirates, from bottlers in Dubai Industrial City to bakeries in Sharjah and processors in Abu Dhabi's industrial zones. It works backwards from the symptoms you see on the line to the cause and the fix.
TL;DR
- Desalinated network water carries some hardness after it is remineralised for distribution. Plants concentrate it.
- Start from the symptom: where the deposit is tells you which stream needs treating.
- Cooling towers and boilers are usually the biggest problems, because they concentrate minerals by design.
- Softening protects heated circuits. RO with controlled remineralisation is the route for product water with a defined profile.
- Confirm your food authority's expectations (Dubai Municipality, ADAFSA or your emirate's authority) before changing product or rinse water.
In this article
- Soft supply, hard deposits: why both happen
- Symptom finder: what the deposit is telling you
- Walk the plant before you buy anything
- Fixes by stream
- Authorities and approvals by emirate
- Keeping it under control after commissioning
- Frequently asked questions
Soft supply, hard deposits: why both happen
Hardness means dissolved calcium and magnesium, expressed as mg/l calcium carbonate (CaCO3). Water straight from a thermal or RO desalination plant contains almost no minerals, which makes it corrosive to pipework, so it is post-treated and blended before it goes into the network, a step the World Health Organization's desalination guidance covers.[1] The water reaching your meter is therefore low to moderate in hardness, not zero.
Inside a factory, that modest hardness is multiplied:
- a cooling tower evaporates water and keeps the minerals, so circulating water can be several times harder than make-up;
- a steam boiler concentrates dissolved solids between blowdowns;
- a CIP heater or bottle washer holds water at high temperature for hours;
- a roof or ground tank warms water in summer and may mix network water with a tanker load or a well supply.
Most of the UAE's groundwater goes to farming, while desalinated water supplies the towns and cities.[2] Well water and tanker loads of unknown origin can be far more mineralised than network water, so a site that tops up from them can see a sudden jump.
Symptom finder: what the deposit is telling you
| What you see | Where | Likely cause | First check |
|---|---|---|---|
| White, crunchy crust on tower fill and basin | Cooling tower | Cycles of concentration too high for the make-up hardness | Make-up and circulating hardness, bleed rate |
| Rising pressure drop, drifting outlet temperature | Plate heat exchanger or pasteuriser | Calcium carbonate on the hot side | Hardness at the heater inlet, cleaning records |
| Spots and streaks on bottles, crates or trays | Washer final rinse | Hard or high-TDS rinse water drying on the surface | Rinse water hardness and conductivity |
| More frequent boiler descaling, higher fuel use | Steam boiler or generator | Hard feed, poor blowdown control | Feedwater hardness, TDS in boiler water |
| Blocked spray nozzles | CIP spray balls, washers | Scale in hot recirculated circuits | Hardness at CIP make-up |
| Taste or texture drift between batches | Product | Changing mineral content in ingredient water | Source records, conductivity trend |
Use the table to decide which streams to investigate first. It is common to find that two or three points of use account for nearly all of the scale.
Walk the plant before you buy anything
Sample in the places the water actually is, not only at the meter:
- The incoming connection from DEWA, SEWA, Etihad Water and Electricity or TAQA Distribution in Abu Dhabi.
- The outlet of every storage tank.
- Any well or tanker supply, even if it is used only occasionally.
- The inlet to each item of equipment you want to protect.
- The circulating water in cooling towers and boilers.
Ask the lab for total and calcium hardness, alkalinity, pH, conductivity, chloride, sulphate and silica. Repeat in August, when evaporation and tank temperatures peak, as well as in winter. Record flows and operating hours for each point of use while you are there. Our water quality and TDS guide for the UAE explains the readings.
Fixes by stream
Boiler feed, CIP make-up, washers and heat exchangers. Ion-exchange softening removes calcium and magnesium and can be checked in minutes with a titration kit. For a plant working in shifts around the clock, an alternating twin unit such as the Regal Twin 3672 keeps soft water flowing while one vessel regenerates.
A single washer or oven line with a quiet overnight window may suit the Commercial Softener RF1465SO1.
Cooling towers. Treat the make-up, then control concentration. Softened make-up, inhibitor dosing and an automatic conductivity-controlled bleed work together. Your water-treatment specialist should set the cycles of concentration against the analysed make-up water.
Product and critical rinse water. Softening swaps hardness for sodium and leaves TDS where it was, so it is rarely the answer for ingredient water. Reverse osmosis removes most dissolved solids and gives a consistent base that can be remineralised to a recipe. The Industrial RO and Multi-Media Filtration system is designed from the site analysis and throughput.
Membrane protection and remineralisation. Antiscalant dosing keeps RO membranes clean, and a separate dosing line can add minerals or correct pH after the membrane. The Sceptre DS130 dosing system covers these duties.
Devices that promise scale control without removing hardness. Magnetic and electronic units do not take calcium out of the water. Ask for independent evidence in comparable conditions before relying on one.
Authorities and approvals by emirate
Food establishments are licensed and inspected by emirate authorities. In Dubai, the Dubai Municipality Food Safety Department controls food establishments, and in Abu Dhabi the Abu Dhabi Agriculture and Food Safety Authority (ADAFSA) licenses and inspects them.[3][4] In other emirates, check with your local municipality. Water used in food, or on product-contact surfaces, must be potable, and changes to how it is treated should go through your HACCP review.
On the utility side, trade effluent from softener regeneration and RO reject is subject to the drainage rules of your municipality or zone authority. Check the conditions for discharge volume and salinity before the design is fixed.
Keeping it under control after commissioning
- Test outlet hardness on each softened stream to a fixed schedule, for example each shift on boiler feed and CIP make-up.
- Put online conductivity on RO permeate, and a hardness monitor where a failure would stop production.
- Track cooling-tower cycles and bleed, boiler TDS, salt use and regeneration counts.
- Keep tank cleaning and inspection on the plan. Warm storage encourages both scale and biofilm.
- Agree who responds to an out-of-limit reading and what happens to product made in the meantime.
A conductivity reading does not measure hardness, so it cannot prove a softener is working.
Planned visits for resin, valves, membranes and dosing pumps keep performance stable. Sovereign Water's maintenance service can cover this once the treatment train is in place. If you also run commercial buildings, our guide to softeners for UAE buildings, HVAC and boilers covers the building side.
Frequently asked questions
If our supply is desalinated, why do we need a softener at all?
Network water still carries some hardness, and cooling towers, boilers and hot rinse circuits concentrate it. Softening the streams that feed those items usually solves the problem.
Which part of the plant should we tackle first?
Follow the deposits. Cooling towers, boilers and heat exchangers are the usual starting points, followed by washers and CIP.
Can we use softened water in our drinks?
It is not usually recommended. Softening adds sodium and leaves dissolved solids unchanged. RO with controlled remineralisation gives a consistent product water.
Does a well or tanker supply change the design?
Yes. Well and tanker water can be far more mineralised than network water, so treatment must be sized for it if it can reach the line.
How often should hardness be tested?
Set it by risk. Critical streams are often tested every shift, with extra checks after any change of source.
Talk to Sovereign Water about your plant
Send us the deposits you are seeing, your water analyses, sources, flows and operating hours. Our UAE team can then discuss a treatment plan for the streams that need it.
Sources
[1] World Health Organization, Safe drinking-water from desalination (2011): https://www.who.int/publications/i/item/WHO-HSE-WSH-11.03
[2] UAE Government portal, SDG 6 clean water and sanitation: https://u.ae/en/about-the-uae/leaving-no-one-behind/6cleanwaterandsanitation
[3] Dubai Municipality, Food Safety Department: https://www.dm.gov.ae/municipality-business/food-safety-department-2/food-safety-department/
[4] Abu Dhabi Agriculture and Food Safety Authority, about ADAFSA: https://www.adafsa.gov.ae/en/about/Pages/default.aspx