Information Sheet

PO Box 348 Official Distributor New ZealandYarrambat Lohil Industrial Services LtdVictoria 3091 487 Te Irirangi DrivePhone / fax: 03 9717 0200 Flatbush

Mobile: 027 2404195 email: noelsmith.sis@gmail.com www.enzymatic.biz Email: Lohil.industrial@vodafone.co.nz

www.lohil.co.nz

Enzyme PRO / Enzymatic and Odour Control Degradation of organic compounds in the absence of oxygen is a principle cause of foul odours. Organosulphur compounds which are naturally present in all organic waste materials break down in the absence of oxygen to yield hydrogen sulphide (H2S) gas associated with the smell of rotten eggs. Incomplete degradation of organic compounds under anaerobic conditions also produces volatile organic compounds (VOC’s). These compounds can vary enormously in chemical composition and are characteristic of the waste from which they are derived. Under anaerobic conditions organosulphur compounds generally degrade to simpler substances containing a sulphur-hydrogen moiety (S-H bond), known as thiols or mercaptans. The mercaptans can further degrade under anaerobic conditions to hydrogen sulphide. If oxygen is available then aerobic digestion takes place. Under these conditions, the biochemical processes lead to the conversion of organosulphur compounds to water and sulphate (H20 and SO4) which are odourless. Also, under aerobic conditions, VOC’s are not produced because organic compounds are completely degraded to carbon dioxide and water which are odourless. The odour that is perceived and that enables humans to differentiate between different odours is the result of a complex interaction between the particular spectrum of VOC’s and the hydrogen sulphide that a given waste produces. Hydrogen sulphide is detectable at extremely low concentrations (the recognition threshold is 0.47ppb). The detectable concentration of many malodorous VOC’s is similarly very low. Thus, although a particular smell may be subjectively identified as “strong” this does not necessarily indicate a high concentration of odour causing compounds. It is a reflection of the response to the particular spectrum of VOC’s that is present. It is rarely possible to detect hydrogen sulphide alone. The assessment of odour resulting from the interplay of hydrogen sulphide and VOC’s is highly subjective. Even a small alteration in the composition of VOC’s or the concentration of VOC’s relative to hydrogen sulphide can result in substantial changes in the subjective assessment of odour. Enzymatic suppresses or controls odour by two different mechanisms. Firstly, it is able to complex with or “capture” volatile organic compounds producing a practically instantaneous reduction in perceived odour. This effect explains why odour may be controlled subjectively even though hydrogen sulphide is still detectable by objective chemical methods of analysis.

Secondly, Enzymatic affects digestion of organic contaminants in two ways:

1. Direct enzymatic catalysis of catabolic processes to breakdown complex molecules into progressively smaller less complex molecules.

2. The smaller less complex molecules act as food substrate for microbes which can then proliferate and further promote biochemical breakdown of the organic substrate. For hydrogen sulphide control, it is primarily the first method of action that is at play. Mercaptase enzymes break the hydrogensulphur bonds of the mercaptans and thiols that are generated at the surface of the organic waste, thus suppressing the generation of hydrogen sulphide. This is the most effective means of controlling the hydrogen sulphide component of the odour.

Hydrogen sulphide itself is a stable and potentially toxic gas. By eliminating the mercaptans and thiols from which it is produced, and thus preventing its formation, Enzymatic eliminates the need for the more difficult task of degrading H2S after it has formed.

It is for this reason that a fine aerosol spray onto the surface is the best way to deal with odor. This needs to be repeated as frequently as required to maintain odor control at the surface once the Enzymatic has been absorbed from the surface into the organic waste or has biodegraded.

A fine aerosol spray is also the most effective way for Enzymatic to capture volatile organic compounds. An aerosol spray generates a large surface area allowing the VOC’s to be efficiently and rapidly absorbed.

When a more comprehensive Biotechnology Solution is implemented in a waste water situation, aeration increases the available oxygen to ensure that efficient full aerobic digestion of the organic waste takes place. This ensures that no H2S is produced and all of this substrate is fully aerobically digested to produce H20 and SO4. In addition, under aerobic conditions, malodorous VOC’s are reduced or eliminated.