COALSI special filter mats — Why it stinks from the sewer and what the solution looks like

As soon as summer is within reach, the authorities are receiving complaints about odors from the sewage system, because the combination of higher temperatures and lower amounts of precipitation causes rapid bacterial growth. COALSI offers activated carbon filters for shaft inlets, which already filter up to 90 percent of bad odors, for other pollutants that exceed the “normal level”, such as hydrogen sulphide (H2S), ammonia and acidic odors, the COALSI system has been expanded to include new special filters that specifically neutralize odour generators.

Why it stinks out of the canal on warm days and what helps

If it rains less, the sewer is not sufficiently flushed, which causes material to be deposited from the waste water. Organic substances such as fats, food scraps and faeces are broken down by hard-working microorganisms, which release H2S, among other things. The warmer it gets, the faster this bio-chemical reaction takes place in the sewage system. In summer, wastewater temperatures can be up to ten degrees higher than in winter, doubling the rate of the bio-chemical reaction when crossed by thumb.

“For bacteria, this is a celebration! At warm temperatures, the microorganisms are at their best, resulting in smelly decomposition products, such as sulfur compounds, which are particularly displeasing to the human nose. In addition, organic compounds of sulfur, nitrogen, oxygen and hydrocarbons quickly damage the structure of the canals, as this mix leads to corrosion,” explains Ulrich Bethge, Head of Sales & Administration at COALSI, an expert in sustainable solutions for roads and canals.

The difference in temperature between the duct and the environment also causes more odour pollution among residents and passers-by — if it is cooler under the manhole cover than above, there is an automatic exchange of air and the stench rises unchecked upwards. The fact that many unpleasant odors are harmless to health is only a slight comfort to those affected.

Filter mats for every area of application

The environmentally friendly way to counter the stench is to send bacteria into the field against bacteria. COALSI hybrid mats fermented with special microorganisms filter the odorous substances so that the channel can continue to “breathe”. The microorganisms metabolize the odour generators; but the filter also works on a chemical and physical level. The activated carbon insert is important: The fine-pored carbon has a catalytic effect and thus neutralizes many odorous components. The positive effect of triple filtration Confirms, for example, the city of Hockenheim, which was able to significantly reduce odour emissions from the sewer with COALSI.

The hybrid mat, which COALSI incorporates as standard in its products, reduces the emission of polluted exhaust air by up to 90 percent. Special filter mats are used for cases of hardship, such as strong odors of fat, fish or hydrogen sulphide:

• Special mat against hydrogen sulphide — for example in the area of yeast-containing waste water
• Special mat against bases — e.g. ammonia in the fishing industry, from paper production or in public toilets
• Special mat against acids
• Combination of the standard hybrid mat with all three special mats

Since the special mats can also be used serially and in parallel, a suitable combination can be found for every odour situation and industry. The COALSI multi-chamber filter can hold up to eight mats.

“There is a suitable solution for almost every problem. Unpleasant odors from wastewater and manufacturing plants should no longer be an issue for citizens, municipalities and polluters, regardless of the season,” says Bethge. The COALSI filter mats are used in road sewer filters, road drain filters, multi-chamber filters and Volumenmax, offer breathable gas exchange and have been proven to be highly effective.

For more information, download the pamphlet down or contact our team.

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