Sewage Odour

Sewage carries biological and chemical contaminants the nature of which will depend on the activities within the catchment and treatment area. Sewage is treated to remove these contaminants to ensure the effluent stream is biologically and chemically safe before discharging it back to the environment.

Under anaerobic conditions in presence of bacteria, sewage effluent produces malodourous gaseous compounds arising from the breakdown of organic material. The main odours produced are hydrogen sulphide (H₂S), with a characteristic rotten egg smell; mercaptans (thiols, R-SH), which resemble smelly socks or decaying cabbages (e.g., methyl and ethyl mercaptan); and ammonia (NH₃), which has a pungent, urine-like odour.

Activated Carbon is used to remove these unpleasant offending odours. VOC’s are efficiently removed using steam activated carbon. H2S, other sulphur species and acid gases are treated using enhanced products either chemically impregnated activated carbons or surface modified catalytic non- impregnated carbons. Historically chemically impregnated carbons have been heavily utilised in H2S acid gas removal. Potassium hydroxide and Potassium iodide bring commonly used impregnants. This type while able to target acid gas species, has a reduced ability to adsorb the organic vapours in the sewage odour mix.

Typically, a layer of non- impregnated steam activated carbon is incorporated as layer in the odour removal vessel specifically to remove VOC’s. Nowadays while we carry the range of standard impregnated Addsorb products, Jacobi’s Addsorb OX30 coconut shell-based surface enhanced activated carbon is increasingly the preferred option. AddSorbTM OX30 is a high-performance activated carbon, based on a sustainable raw material, exhibiting an enhanced capacity for the removal of Hydrogen Sulphide (H2S).

The product is manufactured using a unique process, which establishes the high H2S capacity without the use of a chemical impregnation being applied to the activated carbon. In its place, a reactive surface functionality is established which can convert H2S to sulphur compounds which may be physically adsorbed. In addition, the product retains an appreciable capacity for organic contaminants.

Acid and alkali gases can be harmful to health, to the environment and to the systems with which they are processed.

Occupational exposure to acid gases can irritate the respiratory system causing symptoms of coughing shortness of breath and chest tightness. Prolonged exposure can lead to systemic effects including headache, nausea, vomiting, dizziness and fatigue.

Acid gases causing corrosion in plant equipment and can lead to equipment failure, safety risk and economic losses due to increased plant maintenance requirements. Alkali gas is predominately ammonia but may also comprise sodium hydroxide fumes and odours from light amines.
Jacobi AddSorb range of enhanced activated carbons are used to remove acid gases such as hydrogen sulphide (H2S), carbon dioxide (CO2), hydrogen chloride (HCl), sulfuric acid (H2SO4), hydrogen fluoride (HF), and nitric acid (HNO3) from gas and air. Often used as a polisher after technologies such as wet scrubbing, it is also employed in air condition systems protecting control room and environmental air.

Specialist products capture other inorganic contaminants such as ammonia,
mercury, arsine, formaldehyde and phosphine.