Controlling Biological Odors in Paint Spray Booth Systems

Problem Description

Industrial wet paint spray booth systems can be the source of many odors, be it in the booth itself or in related locations such as the booth sump or sludge room.  Many of the odors are a direct reflection of the materials that make their way into the system – paints, solvents, chemical additives, and more.  Other odors, such as biological odors, could be the signal of a much more serious problem.

These unpleasant odors can lead to worker complaints, lost productivity, and health concerns.  What the odors could also be indicating is that the system is in trouble and that other problems are on the horizon, such as booth operating efficiency, stack emissions control, increased booth maintenance costs, and booth component longevity.

Most biological odors are caused by anaerobic bacterial.  These microorganisms prefer to hide underneath deposits and aerobic biological slime, or deep within sludge masses which have accumulated in the paint spray booth system.  Aside from the obvious unpleasant odor, the bacteria could be working overtime plugging up back sections, spray headers/nozzles, and other booth water components.  This can lead to loss of scrubbing efficiency and untreated paint overspray, resulting in live paint emission and live paint deposits throughout the system.  The anaerobic bacteria which reside underneath the deposits are corrosive, creating the potential for premature both component failure and spiraling maintenance costs.

The Solution

Paint spray booth systems can provide all the ingredients needed for biological growth – moisture, chemical nutrients, oxygen for aerobic bacteria and hiding places or growth sites (solids) for anaerobes, the primary odor causers.

Adequate paint detackification (detack) and solids removal are necessary to minimize the solids build-up which can be the seed for biological growth.  Galaxy offers a broad spectrum of paint detackification and solids agglomeration programs to work in tandem with the sludge processing equipment.

Routine clean-up of booth water locations where solids tend to accumulate is the single most important maintenance chore, aside from chemical treatment, for reducing the ability of anaerobic bacteria to hide out and send their odorous signals.

All odors outside of the booth can be dispersed with adequate ventilation.  However, this doesn’t address the source of the problem (the bacteria), but can provide temporary relief until longer term solutions are in place.

The use of odor maskants can also provide temporary relief, but this only hides the problem leaving the impression the odor has gone away.  In reality, booth performance could be fading every day as the real source of the problem cuts into profits slowly but surely.

Treating the booth recirculating water and booth humidification systems with approved and effective biocides is many times a necessity in paint spray booth systems.

There are two general families of biocides – oxidizing and nonoxidizing.  Some general comparisons of these two biocide groups are shown below:

Oxidizing Biocides (Halogens) Nonoxidizing Biocides
Nonselective organic oxidizer – consumed by organics and oxidizable substances – aka “demand” Not consumed by organics – specific to biological organisms.  Some are consumed by high bulk water solids
Relative low cost per pound (gas/liquid/solid) Moderate to high cost per pound
Use cost variable depending on “demand” Use cost a function of bio-demand
Gaseous chlorine – safety concerns Generally sold as liquids
Liquid chlorine can degrade in container over time esp. in light and with temp. Shelf lives can be 1 year + when stored properly – closed container/cool location
Halogens can be corrosive Generally not corrosive
Halogenated compounds (i.e. chloramines) can release odors Some biocides have an odor
Versatile – effective on many types of organisms Can be specific to certain types of microorganisms

Bio dispersants/wetting agents can be used to supplement a biological control program.  These products allow faster penetration of the biocide into the biomass and can indirectly help with biological control by preventing the biomass from accumulating.

So, biological odors can be kept in check when the proper combination of chemical treatment, equipment maintenance, and biocide application are used together.

Consult with Galaxy Chemical for all of your paint spray booth chemical and technical needs.

Controlling Biological Odors in Paint Booth Systems