this is super easy and cheap, Anghel. put in a small in situ bioreactor. it will keep on producing probiotics for many years. you never have to buy microbes. the probiotic will remove all H2S smell. and you don't need to buy, you can rent for cheap for many years.
I have some assumptions about your problem: I assume your WWTP is an aerobic process and you may have a sludge digester.
I also assume the digester is under control and is NOT the source of odors. I say this because the gases usually are collected and incinerated or used as bio-gas for heating-steam generation.
To have some guidance into the control of odors we may have insight into the generation of such odorous gases.
Odors in general are mercaptane gases (gases with a double link of Sulfur to alkanes) which generate on anaerobic conditions. If you were in certain regions of the world where sulfates are very low, most probably you will NOT have this problem. In places where the sulfates are relatively high mercaptanes appear easily and give you odors. This may occur even inside pumping wells. If the sewer has medium strength (or higher strength) and if the sewer system is long this is even easier.
In the process of generating the odorous gases, there is a step where Sulfur becomes detached from the Sulfate oxygen and chemically active. It is at that time that you can act. I have used Ferric chloride to do so, because the ionic iron is very reactive with the sulfur creating an insoluble compound (an not odorous) named pyrite FeS. This addition has to be followed closely, because Ferric chloride is also a coagulation-flocculation agent.
There are compounds sprayed, masks or either favor oxidation or change the odor, but in general this methods are after the odorous gas is already there.
Bio filters are good but take a large toll on your real state and maintenance, thus I only suggest them after the optimization of the process and measure to correct the generation of odorous gases is tried.
If you need clarification or further assistance contact me at rafael.gaydemontella@gmail.com or call 514 575 5290 (whatsapp)
L'odeur qui se dégage de votre STEP est la même qui émane de toutes les STEP du monde. Cette odeur provient de la matière organique en putréfaction. Une putréfaction enclenchée par la méthanisation du milieu. il n'y a rien à y faire.
la seule solution qui a été trouvée jusqu'à ce jour est celle que vous devez certainement utiliser: le bac d'aération. L'apport d'air libre tue l'action de la méthanisation du milieu avec des dommages collatéraux: une forte émanation d'air vicié dans l'atmosphère environnant.
Ce bras d'aération supprime également toute possibilité de création d'un état sans oxygène par l'injection d'oxygène. Pour qu'un état sans oxygène puisse se créer il faudrait du temps (compris en année), que l'on injecte pas d'oxygène libre, que le mileiu reste stable durant des années.
Hors vu le débit entrant sur une STEP c'est loin d'être le cas. Je suis effaré que des personnes puissent encore parler d'état sans oxygène sur la terre qui est totalement aérobie.
En assainissement biologique il n'y a pas d'émanation de putréfaction par la méthanisation car l'action du process est justement de conserver totalement les caractéristiques biologique du milieu en état aérobie.
Hello
The smell that emerges from your step is the same that emanates from all the steps of the world. This odor comes from rotting organic matter. A rot triggered by the anaerobic digestion of the medium. There is nothing to do.
The only solution that has been found to date is the one that you definitely need to use: the aeration bin. The supply of free air kills the action of the digestion of the environment with collateral damage: a strong emanation of stale air in the surrounding atmosphere.
This aeration arm also removes the possibility of creating an oxygen-free state by injecting oxygen. For a state without oxygen to be created it would take time (included in the year), that no free oxygen is injected, that the medium remains stable for years.
Out of sight the flow entering on a STEP is far from the case. I am frightened that people can still talk about oxygen-free State on Earth which is totally aerobic.
In biological sanitation There is no rot emanation by the anaerobic digestion because the action of the process is precisely to preserve the biological characteristics of the environment in aerobic condition.
See Edward Blackmore. Biofilters are a very good option and are not hard to build. I have smelled them work on ATAD air with reduced sulfur compounds. Quite a feet since some of those compounds you can smell to half a part per billion. I have worked with mechanical/ chemical systems and there is less operator input to the biofilter.
Rising Temperatures - Temperatures are rising as we come into the summer months and with this, the temperature of the wastewater also increases. As a result, aerobic bacteria become more active and begin digesting BOD and other nutrients at a faster rate. The warmer the water becomes, the more active they are and the more oxygen they consume. This results in low dissolved oxygen.
Anoxic Zones - Low dissolved oxygen coupled with rising temperatures can lead to an increase in anoxic zones at the bottom of wastewater aeration basins. Anaerobic digestion releases sulphur dioxide, along with a variety of other noxious gases that are the causes of wastewater odour.
Usual Solutions (to act on causes):
Increase Oxygen Supply - Increasing oxygen supply ensures that the aerobic bacteria have the oxygen they need to aerobically digest BOD. This will help to control odours as anaerobic digestion will slow down.
Wastewater Circulation - Ensuring dissolved oxygen is reaching the very bottom of an aeration basin is key to avoiding odour as this is where the odour-causing anaerobic digestion occurs. By circulating the wastewater effectively, you can create nearly equal dissolved oxygen throughout. This in turn will promote odour-free aerobic digestion.
Could you share the type of effluent is it and /or some data of the activated sludge aeration?
Containing and filtering the gases may be another solution. Capex and opex depends a lot on the size of your plant.
Is the odour being generated in the treatment plant or odour arriving from the influent to the treatment plant? Ferric chloride dosed in the sewer catchment works well but is a dangerous good, Magnesium hydroxide liquid (MHL) also works well, but is difficult to dose. Biosol an Australian product, has been shown to out perform both MHL and Ferrous chloride in terms of odour reduction when dosed correctly. Its foot print is about 1/3 of what is required for MHL or Ferrous chloride, it is non hazardous and also has far better phosphorus control than ferrous chloride. Contact sales@biosol.net
Our media is used to capture P from final effluent however when used in the treatment process not only will it bind P but also considerably reduce odour.
we would need to design a solution around the source of the odour this is very effective our solution is used on landfill an reduces the odour.
Be mindful that the odour problem may not come from the WWTP! As I found out in one of my case where complaints were recorded at a time where the wind direction recorded made it impossible for the people to have smelt anything from the WWTP another source was identified.
If you want to investigate our solution please get in touch.
As already answered, and as you wish, we have to know the sourse of the smell. First of all we have to know the waste water type, quality and treatment. After this, we have to undestand the sourse and the chemical composition of the odour, in order to deside if it is possible to prevent it from the source or to deminuish it (the odour) using chemical reagents.
I would recommend a biofilter to treat the off gases. The media used in the biofilter can be specially impregnated to treat the exact mix of H2S, VOC, mercaptans etc.
Our company specializes in industrial and municipal odor control. There are no simple answer to this questions, and it is important to understand the source and nature of the odor to suggest a suitable solution. Feel free to contact me at lleroux@bioairsolutions.com and we would be happy to discuss this in more detail. Here is a possible helpful link -
As one of the responses above, I would suggest covering the odor sources and venting to a biofilter. Assuming the major sources are the headworks and dewatering should be fairly easy to accomplish. The activated sludge process should not be causing odors if it is healthy. Be very careful if you consider adding chemicals to avoid killing off the activated sludge biomass.