Hydrogen Sulfide Reduction In Waste Water Collection Systems - Buznew.com


Hydrogen Sulfide Reduction In Waste Water Collection Systems

By Harriett Crosby

When organic material is digested in absence of oxygen in what is known as anaerobic digestion, it results to production of hydrogen sulfide gas among other products. This gas is colorless and has a characteristic of foul smell. Normally, this kind of bacterial activity occurs in sewers and swamps. It is no wonder sewers produce a bad smell like that of rotten eggs because of this gas. There is need for hydrogen sulfide reduction in the sewers as showcased in this article.

There are usually a lot of concerns among environmental specialists with the production of this gas in the sewage system. This is because it contributes greatly to the rust problems in the sewer structures and also people living near sewage systems always complain of odor problems. For people wondering how corrosion comes about, it results when the sulfide gas produced combines with water in the system resulting to formation of hydro sulfuric acid that corrodes infrastructure.

There is thus need to control the production of this gas in waste water collection system to very low levels. One way which specialists have found to reduce production of this gas is through addition of a strong alkali or soluble basic solution. The basic solution for instance sodium hydroxide (NAOH) or magnesium hydroxide when added to sewage increases the pH and this leads to limited formation of the gas.

Another way devised to control the odor problems is through addition of chemical compounds also known as chemical treatment. The most used compounds in this treatment are chlorine compounds like sodium hypochlorite, calcium hypochlorite, ferric chloride and bleach. They are added to the sewage and they oxidize the sulfides hence preventing formation of the gas.

There is usually problem however when using this chemical treatment; when there is no pumping section to feed the chemicals into the system, this procedure cannot work well. For this reason, specialists have to create a pumping section first before beginning the procedure. When the feed system is established, it has to be monitored constantly to ensure the treatment is effective. Other than this, safety is always considered during this procedure.

For the rust problems, several measures exist to control this. The first one involves increased ventilation in sewer system to allow aerobic digestion to occur rather than anaerobic. The other measure is use of protective coatings when manufacturing sewer pipes and tanks. These coatings can be polythene linings, cement, vinyl, tar products and the do prevent corrosion of the infrastructure.

Crown and manhole spraying is yet the other measure used in corrosion control. When the hydro sulfuric acid is forms, it collects mostly at the crown part of the pipe. The effect on this area is intense decomposition leading to weakening of the pipe and in worst cases collapse. Therefore a Sulfa Lock Gel is sprayed on these areas so as to prevent the bad effects of hydro sulfuric acid.

There is also a monitoring instrument known as a liquid phase sulfide meter that monitors the amount of sulfides in industrial wastes. When the sulfide content is beyond the required amount, the industrial discharge undergoes pretreatment before being released to sewer system. All these control strategies used in hydrogen sulfide reduction in sewers work together to prevent corrosion and odors. Scientists are however still coming up with new chemicals and instruments to effectively manage this problem.

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