By John Caloritis
Cooling Water Filtration can be an extremely valuable tool for building owners to take advantage of. Applied correctly and consistently, the conventional PM chemical treatment program will function well to control problems with dissolved solids, microbial fouling and corrosion. However, pesky “suspended” solids should not be overlooked for the damage they can cause. Suspended solids are a separate and unique challenge from the ones mentioned above, and can contribute to other related problems such as accelerated corrosion/erosion, heavy fouling of transmission lines or heat exchangers, and especially, support the development of disease-bearing organisms.
Suspended solids will typically enter tower systems through the adjacent air stream as tower water and air co-mingle to allow for the rejection of heat. In fact, by their very operation, towers may be considered “air washers” inviting whatever local particulate may be in the nearby environment (parking lots, roadways, fields, pollution, etc). However, suspended particles can also be introduced through other pathways. Among those are a) unchecked micro-organisms allowed to develop into dangerous bio-films, b) unresolved corrosion problems whereby iron or copper are converted into suspended particles, or even c) excessive chemical treatment, whereas certain classes of chemicals themselves become suspended and problematic by oversaturation.
The prevailing wisdom for owners is that their water treatment programs alone can handle all problems. While this may be true where generally clean conditions exist, in most situations, bleed-off and treatment alone will not be enough. So, filtration of suspended particles is the smart option to consider. Filters come in many forms and use different approaches. Among them are sand filters, separators, bags, or cartridges. Coupled with secondary circulation pumps and piped strategically, filter offer building owners many benefits. The primary benefit is of course the reduced potential for water system fouling. Other benefits include reduced biocide demand, lower tower cleaning costs (completed faster), reduced dirt loadings, and improved bacteria control. The aforementioned strategic piping arrangements could also help to provide a separate means of continuous circulation when loads are variable, plus provide a way to “sweep” the pans continuously from debris. Keeping the water moving is another key strategy to minimize fouling, and enhance protection. Owners are encouraged to use water filters wherever warranted.
