We all make decisions on a daily basis…
Fundamental decisions: “Should I go to work today?”
Semi-important decisions: “Can I make this yellow light?”
Trivial decisions: “Cheese and onions on my chili dog?”
Some decisions, though, are more ambiguous than others especially when it comes to descaling. If you need to remove mineral deposits from a heat exchanger, chiller or any equipment that comes in contact with water on a regular basis, there are several different methods from which to choose.
Is it best to go with cleaning it mechanically (e.g. tube cleaners, rod and brush) or chemically (e.g. acids)?
Here’s an overview of the most common cleaning methods, as well as the advantages and disadvantages of each:
Rod and brush
This method is pretty self-explanatory. You have a rigid or flexible rod with a wire or nylon brush on one end that is manually pushed through the tubes to scape off the deposits and then flushed out with water.
• Simple process requiring minimal training
• Fairly low cost of equipment (e.g. brushes)
• Ineffective on dislodging hard or thick deposits; deposits left behind expedite additional fouling
• Extended downtime; labor intensive
• Brushes can get lodged inside tubes or cause breach
• Generates waste that must be properly disposed
Water blasting & rotary/gun tube cleaners
High-pressure air and/or water propel a projectile, such as a metal or plastic scraper or brush, through each tube to dislodge deposits followed by a water flush. Rotary tube cleaners have a rotating flexible shaft encased in plastic that transports water to a cleaning tool located on the end allowing for cleaning and flushing in a single pass.
• Each individual tube can quickly be cleaned
• Effective at dislodging several types of deposits with moderate buildup
• Flexible shaft can reach curves/bends
• System, accessories and service are costly
• Extended downtime; labor intensive; dismantling of equipment necessary to insert and recover projectiles
• Projectiles and other cleaning tools may get lodged inside tubes
• Ineffective on heavy deposits; any deposits left behind expedite additional fouling
• Generates waste that must be properly disposed
• Safety concern; potential for blow-back of projectile at operator under certain circumstances
Chemicals, more specifically harsh acids, are circulated through equipment or systems dissolving deposits and then followed by a water flush. There are several types of acids on the market, including nitric, citric, phosphoric and hydrochloric, among others.
• Effective on dissolving calcium carbonate deposits
• Ability to reach all parts of equipment or systems
• Can be more effective than mechanical methods
• Highly corrosive to metal and other materials if not properly used
• Elevated health and safety risks; must wear proper protective equipment to handle
• Special permits may be required in some circumstances requiring additional time and money
• Disposal can be costly and difficult due to hazardous nature and various disposal regulations
RYDLYME and how it evolved chemical cleaning
After reading the overview of chemical cleanings, you may think the disadvantages far outweigh the advantages. You also might come to the conclusion that we are a few cans short of a six-pack listing the disadvantages of chemical cleanings since we manufacture chemical cleaning products. But the fact of the matter is that not all chemicals are created equal.
Apex Engineering Products Corporation is not just a chemical manufacturer; we are a SAFE chemical manufacturer. Our flagship product RYDLYME, is a safe, biodegradable descaler that has all the advantages of a chemical cleaner with NONE of the disadvantages.
That’s what makes RYDLYME unique and why it has been around for more than 70 successful years. It transcends mechanical cleaning methods and takes chemical cleaning to another level. Here’s why…
• Non-hazardous; non-toxic
• Safe for personnel, equipment and environment
• Can be held in open hand without injury
• Biodegradable; dispose safely down normal plant sewers
• Simple setup
• Safe to use on a wide variety of metals and materials
• Dissolves even the heaviest and hardest mineral deposits (e.g. iron oxide)
• Use for clean-in-place or even online cleanings to prevent shutdown
• Fast; minimal downtime
• NSF/ANSI Standard 60-certified (cleaner for potable water systems)
The decision to clean your equipment may be a simple one, stemming from an immediate need (e.g. overheating heat exchanger), semi-immediate need (e.g. loss of efficiency, increased operating cost), or precautionary need (e.g. routine preventative maintenance).
Deciding on what method or products to use may prove to be a little more difficult, but it shouldn’t. Conduct some research into what might be best suited for your cleaning needs. Whether to go with a mechanical or chemical cleaning (something may be amiss if you end up doing both) may depend on budget, time, regulations, and a variety of other factors.
Though RYDLYME is the “World’s Leading Biodegradable Descaler”, find out for yourself that it’s true.
Contact us or go to our website at www.apexengineeringproducts.com to review our case studies and learn about how we’ve saved companies time and money. Also, contact us to find out who our representative is in your area. They will come out to your facility to discuss your needs, as well as provide a unique demo of the product.
The decision to use RYDLYME should be an easy one. Once that decision has been made, you just need to figure out what you want on your chili dog.
A 6-foot heat exchanger at a facility for a major gas supplier on the east coast was experiencing a 35°F increase in temperature at the water outlet, which resulted in high Delta Ts.
• 10 gallons of RYDLYME circulated for 4 hours via RYDLYME 10MDC pumping system.
• There was a 30°F drop in temperature and the Delta T was returned to normal!
• Client only had one comment, “Unbelievable.”
• Client plans to use RYDLYME on two more heat exchangers and six aftercoolers, as well as the facility’s entire cooling loop system!
A 1,200-ton ammonia condenser at a turkey processing facility experienced scaling on the exterior of the tubes. This scaling caused significant issues with proper heat transfer and in turn, not cooling the ammonia inside the tubes for proper refrigeration temperatures.
• 660 gallons of RYDLYME circulated for 8 hours via inline pumps.
• Scaling throughout the tubes was dissovled restoring proper heat transfer and refrigeration temperatures, which is critical for this and other food processing facilities.
• The client purchased additional totes of RYDLYME to clean three more ammonia condensers.
• RYDLYME has also been incorporated into the preventative maintenance guidelines of these units.
Getting RYD of grease, grime and more!
RYDALL MP Multi Purpose Degreaser & RYDALL DD Definitive Degreaser Case Studies
An industrial cleaning contractor needed a degreaser/cleaner to cut through a significant buildup of oil, carbon black, grease and other contaminants on a Banbury mixer from a tire manufacturing facility.
• 5 gallons of RYDALL MP (50% solution) sprayed on entire unit, soaked for a few minutes and then powerwashed with water.
• In only one hour, and simple soaking and rinse, the mixer was free of grease and other contaminants!
• Client was extremely impressed and contractor was eager to use RYDALL MP for additional jobs!
A waste management company was experiencing problems thoroughly removing contaminants from plastic containers that were being cleaned to prepare them for recycling.
• RYDALL MP diluted (10% solution) into the parts washer, heated to approximately 120°F and sprayed continuously onto the contaminated plastic followed by a water rinse.
• Setup allowed good coverage on material passing through, cleaning each thoroughly for recycling.
Heat exchangers (8-inch diameter, 6 feet long) at a Midwest glass manufacturer had 2 to 3 years worth of baked on oil and other contaminants that no other products were able to remove until they tried RYDALL DD.
• RYDALL DD circulated via pump at 160°F for 4 hours.
• Circulation at elevated temperatures removed the baked-on oil throughout the tubes, restoring proper flow and temperatures.
• The client stated that he was, “Completely astounded by the results. [RYDALL] DD made those tubes look brand new!”
Filamentous bacteria: The culprit to foaming, bulking
Though a vital part of activated sludge processing, these bacteria can also be detrimental to the process if they get out of hand.
Filamentous bacteria is not the name of a punk rock band. They are bacteria that proliferate and play a vital role in the activated sludge process.
These long strands of bacteria interconnect with each other to form a mesh that is the key factor in flocculation or floc formation, which is the separation of a fluid or removal of sediment from a fluid. This mesh holds together the floc to form manageable portions for better settling, as well as snag smaller particles to help maintain acceptable effluent. Filamentous bacteria also do an exceptional job at removing BODs (biochemical oxygen demand).
There are several types of filamentous bacteria, all of which can potentially cause problems. The key to successfully utilizing these bacteria is balance. Too few of them and the floc cannot properly form. Too many of them and the floc cannot properly settle. The overabundance of these bacteria also absorbs excessive amounts of organic material and inhibits the growth of more desirable organisms. The most common issues that stem from this are sludge bulking and foaming.
Sludge bulking occurs when the sludge becomes light, increases in volume and will not settle. Various floc particles begin interlocking (interfloc bridging) forming massive segments. Many times, these segments trap air bubbles, causing it to float on the surface (sludge scum or foam). The increased surface areas of these masses without an increase in mass to accommodate this condition interferes with the compaction and settling of the sludge resulting in bulking. This also results in a high Sludge Volume Index (standard measure of the physical characteristics of activated sludge solids), overload of the solids handling systems, additional haul-off costs, and degradation of quality effluent.
Sludge foaming is the result of the overabundance of specific types of filamentous bacteria, mainly Nocardia and to a lesser extent Microthrix parvicella. An opportunistic strand, Nocardia thrive when nutrients are low and the health of naturally occurring bacteria is vulnerable, as well as the presence of high levels of FOG (fats, oils, grease) among other factors.
Various types of foam can be produced during sludge processing, including at startup of activated sludge plants, which disappear once the process is established. Another type is brown, heavy foam that accumulates on the surface of the aeration tank and then transfers to the clarification tank where it can overflow if the foam gets too thick and won’t settle. The quality of the effluent discharged from the tank is also severely degraded with high levels of TSS (total suspended solids).
This brown foam occurs when undigested nutrients rise to the surface, but can be the result of a fault in the system and not necessarily Nocardia. A key indicator, though, of foam caused by Nocardia is low BOD levels.
Maintaining the desired levels of dissolved oxygen, F/M (low organic loading rate), nutrients and pH are all vital to an efficient and health activated sludge process. When issues (e.g. bulking) do occur, the addition of remedial methods such as chlorination or hydrogen peroxide can temporarily stabilize the filamentous bacteria population when properly applied.
Balance is the key to controlling filamentous bacteria, as well as the overall biological health of the system. Do your research on products and systems that may enhance your specific activated sludge processing system. Take extra caution with products that are designed to introduce a new biological component to your system. This can negatively affect the biological makeup of your system, creating a more substantial and costly problem.
RYDALL WO Water Optimizer naturally controls filamentous bacteria by supplying “good” bacteria with nutrients and vitamins to sustain a healthy and productive biological environment for activated sludge processing. Please visit www.apexengineeringproducts.com to learn more.