The two human senses that respond to molecular stimuli are taste and smell. The sense of taste responds to dissolved substances. They are characterized as being sweet, salty, sour, or bitter. The sense of smell responds to volatile chemicals in the air. There are at least seven basic odor types, but they are not as well characterized as the taste classifications.
As we all know, odors range from pleasant to obnoxious. The former are enjoyed, and the latter have been cause for development of strategies for their control. It has long been known that substances that have more pleasant odors, such as perfumes, can mask obnoxious odors. A more sophisticated though less well developed strategy of odor control is the prevention of release of obnoxious volatile organic molecules into the air or their removal from the air. Greening Solutions Inc. products exploit these mechanisms to control odors. Before discussing mechanisms of odor control, we should discuss those substances that cause the odors we want to control.
The types of odor causing compounds that elicit negative reactions are most commonly hydrogen sulfide, ammonia and carboxylic acids of medium chain length. By adjusting solution pH, all of these may be converted to ionized forms, which are not volatile and, consequently, have no odor. For example, raising the pH above about 9 converts dissolved H2S to HS- and S=. Likewise, raising the pH of a carboxylic acid above 4 or 5 converts R-CO2H to R-CO2-. However, some other substances may be converted to non- volatile forms by lowering the pH below 8, which will, for example, convert NH3 to NH4 +.
Making the pH changes to convert substances to non-volatile, ionized forms is not always practical. If two or more odor-causing components are present, it may not be possible to pick a pH range where all are in an ionized, non-volatile form. Thus, more practical strategies of controlling or preventing odor at their source or in the atmosphere are required. Odor Control in Liquid-Phase and Wet Sources Wastewater, Sludge, and compost piles are commonly characterized by foul odors. Compounds causing offensive odors, such as hydrogen sulfide and ammonia, are often the products of anaerobic metabolism using nitrate and sulfate as an oxygen source. Fostering aerobic microorganisms and aerobic metabolism of waste materials can often bring about prevention of formation of these compounds at their sources.
Greening Solutions Inc. products contain enzymes and proteins that convert odor-causing molecules to non-volatile or inoffensive forms. Furthermore, the product promotes the
growth of aerobic bacteria, which, in the presence of sufficient aeration, oxidatively metabolize molecules that may otherwise go into the vapor phase and be detected as obnoxious odors.
When used in treating compost, they are sprayed over the pile, and the pile is turned. A beneficial effect is usually obvious within hours. Odor Control in the Vapor Phase Once odor-causing molecules have escaped into the atmosphere, their control is no longer a matter of simple pH control or oxidative metabolism by microorganisms. Skunk Out acts by physically removing odor causing molecules-both obnoxious and pleasant-from the air. The system releases an ultra-fine aerosol that absorbs these molecules. The chemical and enzyme components of this aerosol may further react with the odor causing molecules to prevent them from returning to the vapor phase. The Company’s Odor Control System removes obnoxious odor from air in seconds.