By Eamonn Ryan, from a TechTalk hosted by SAIRAC Cape Town Centre.
In a recent technical talk, Pieter de Jager, owner of Procontrol, a leading provider of water treatment solutions, shed light on the critical importance of effective water treatment in cooling systems. This is Part 3 of a 5-part series.
De Jager then discusses the increasing integration of Building Management Systems (BMS) in larger, modern buildings. These systems provide remote monitoring capabilities, allowing operators to track various parameters from a central computer. One crucial feedback point is the make-up water meter. This not only controls the dosing of anti-scaling and corrosion inhibitors but also provides valuable insights into water consumption patterns. A sudden increase in water usage can signal problems such as a malfunctioning ball valve causing overflow leading to wasted water, increased chemical consumption, and a drop in conductivity within the cooling tower. In such cases, the water in the tower might even have the same conductivity as the tap water, indicating a continuous loss and replacement.
Chemical consumption is calculated based on evaporation rates, which fluctuate seasonally. The service reports provided to customers detail chemical usage and other relevant parameters, allowing for transparency and early detection of potential issues.
De Jager extends the discussion beyond cooling towers to highlight other industrial applications where precise dosing and chemical management are crucial. De Jager illustrates the adaptability of their dosing systems in industries such as fruit packing and processing. Here, similar principles of probe-based chemical level monitoring and automated dosing pumps are employed to ensure the wash water meets stringent quality standards, particularly for export purposes. He showcases custom-built control panels, often featuring digital pumps and protective windows to allow monitoring without compromising the enclosed environment.
Another application highlighted was pH control in agricultural settings, specifically for water used in cooling towers. De Jager describes instances where the raw water source, such as borehole water, has a problematic pH that needs adjustment to optimise the effectiveness of the water treatment chemicals. He also touches upon the challenges associated with using borehole water in general. When borehole water, often containing higher levels of iron, is exposed to air in open dams, the iron oxidises and precipitates out, potentially causing fouling and other issues in the downstream systems.
Returning to cooling systems, de Jager points out variations in dosing system configurations based on specific needs. For systems with multiple towers sharing common lines and isolation valves, they implement dosing on the common line to ensure continuous chemical treatment regardless of which tower is operational. He presents an example of a control panel with two diaphragm pumps, catering to such scenarios, sometimes alongside a peristaltic pump for specific dosing requirements.