Why is SO2 Present in Wastewater?

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Hi guys,

I wanted to know why and how SO2 is present in waste water ?

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8 Answers

  2. Basically in a situation where there is a lack of dissolved oxygen in the wastewater which is normal depending on the sewer design anaerobic organisms will start to strip oxygen from whatever source they can. If there is a lot of sulphate in the water this can lead to SO2 and ultimately to H2S formation. The if we could get this to happen with drinking water without having to add organics it would be a lot easier to reduce nitrate concentrations

    1. Sulfur molecules can be found in most groundwater. Whether it occurs as sulfate, bisulfide, or hydrogen sulfide depends on the amount of oxygen in the water and, to a lesser extent, upon its degree of acidity Sulphur occurs naturally in soils, rocks and minerals. In the aquifer, groundwater comes in contact with these solid materials dissolving them, releasing their constituents, including sulphur (S), to the water. In groundwater, under typical pH conditions, sulfur can occur as three separate ions: sulfate ([SO4] 2-), bisulfide ([HS]1-) and hydrogen sulfide (H2S)From an aesthetic point of view, however, the molecule H2S is probably the most offensive, having the distinct and unpleasant odour of rotten eggs.
    2. Number of organic ​compounds have ​traces of ​sulphites, ​including foods ​we eat. Edible oil etc.
    3. Oil refineries, petrochemical.
    4. Anthropogenic Source.
    5. Sulphur Cycle.
    6. Industrial waste.
    7. Sewage waste.
    8. Sulfur is present in human and livestock excreta and sulfates are found in most water supplies. Sufficient sulfur is normally available in domestic wastewater in the form of organic sulfides such as mercaptans, and disulfides for the production of odorous gases by anaerobic and facultative bacteria.
    9. The sulfate ion (SO42-) is one of the most universal anions occurring in rainfall, especially in air masses that have encountered metropolitan areas. Sulfate concentrations in wastewater can vary from only a few milligrams per liter (mg/L) to hundreds of milligrams per liter. Generally, for domestic wastewater, the main source of sulfide is sulfate.
    10. Sulphur mostly present in coal, heavy oil, natural gas, gaseous fuel that is the source of most of the industries waste.
    11. Hydrogen sulfide is the most commonly known and prevalent odorous gas associated with domestic wastewater collection and treatment systems. It has a characteristic rotten egg odour, is extremely toxic, and is corrosive to metals such as iron, zinc, copper, lead and cadmium. Hydrogen sulfide is also a precursor to sulfuric acid formation, which corrodes lead-based paint, concrete, metals and other materials.
    12.  The conditions leading to H2S formation generally favour production of other malodorous organic compounds. Thus, solving H2S odour problems can often solve other odour problems as well. Many of the odours detected in wastewater collection and 

     

    2 Comments

    1. Toute matière organique sur terre est de l’ordre du Vivant. Quand le souffle de Vie du Vivant cesse, Mère Nature enclenche systématiquement son processus d’élimination.  Le sulfure d’hydrogène est l’élément déterminant du processus de destruction de la matière organique: la putréfaction. Les eaux usées composées de matières organiques diverses contiennent de l’eau H2O. Tant qu’il y a de l’eau il y a 2 molécules d’oxygène et même si son taux de présence diminue, nous sommes en milieu Aérobie. Tant qu’il y a de l’eau il ne peut pas y avoir la présence d’un milieu sans oxygène, l’anaérobie. Pour qu’un tel milieu puisse se créer et se maintenir il faudrait des milliards d’années surtout dans un environnement en perpétuellement mouvement. Le transit et le brassage des eaux usées ne favorisent aucunement la création d’un tel état en si peu de temps. A cela il faut ajouter qu’un être Vivant comme la bactérie, qui a besoin d’oxygène pour survivre, va mourrir en si peu de temps avant d’avoir pu changer d’état. L’anaérobie est une simple vue de l’esprit d’un milieu en putréfaction. Le passage de l’état de Vivant à la mort, un état obligatoire et irréversible de destruction/transformation.

      English

      Any organic matter on earth is of the order of the living. When the breath of life of the living ceases, mother Nature systematically initiates her process of elimination.  Hydrogen sulphide is the determining factor in the process of destroying organic matter: rot.
      Sewage composed of various organic matter contains H2O water. As long as there is water there are 2 molecules of oxygen and even if its presence rate decreases, we are in an aerobic environment. As long as there is water there can be no presence of a medium without oxygen, the anaerobic. 
      For such a medium to be created and maintained it would take billions of years especially in an environment in perpetual movement. The transit and mixing of sewage does not encourage the creation of such a state in such a short time. To this it must be added that a living being like the bacterium, which needs oxygen to survive, will die in such a short time before it can change state.
      Anaerobic is a simple view of the spirit of a rotting medium. The transition from the state of living to death, a mandatory and irreversible state of destruction/transformation.

    2. Thanks 

  5. Bonjour 

    il et très difficile de comprendre comment un milieu liquide en état "Aérobie", en mouvement, à l'air libre,  peut comporter dans un endroit indéterminé, un milieu en état "anaérobie" sans oxygène. 

    On se pose la question de la barrière qui sépare ces deux états, quel facteur permet à un milieu sans oxygène "anaérobie", de se créer librement dans un milieu oxygèné, comment des micros organismes "aérobie" deviennent comme par miracle des micros organismes "anaérobies". 

    L'environnement terrestre est toujours en mouvement, comme l'est également l'effluent d'eaux usées,  décrit  dans le post de Robert qui définit qu'il est oxygèné.

    Il faut des milliards d'années pour qu'un état sans oxygène puisse se créer dans de telles conditions, qu'il puisse se stabiliser et qu'une flore bactérienne n'ayant pas besoin d'oxygène, puisse pérenniser.

    On est dans l'utopie. L'"anaérobie" n'existe pas sur terre, l'"anaérobie" ne peut pas exister sur terre. 

    Dans un milieu qui entre en putréfaction, le pourcentage d'oxygène diminue, et inversement proportionnel, le taux de méthanisation augmente.

    La perte d'oxygène fait ressortir la présence de SO2 d'où qu'il vienne il est important.

    English

     Hello it is very difficult to understand how a liquid medium in an « aerobic" state, in motion, in the open air, may contain in an indeterminate place an « anaerobic" environment without oxygen. We ask the question of the barrier separating these two states, what factor allows an environment without « anaerobic" oxygen, to create freely in a oxygèné medium, how microorganisms « aerobics" become as a miracle micros "anaerobic" organisms. 

    The terrestrial environment is still in motion, as is also the wastewater effluent, described in Robert's post which defines it as Oxygèné. It takes billions of years for a state without oxygen to be able to create itself under such conditions, that it can stabilize and that a bacterial flora that does not need oxygen, can perpetuate.

    We're in Utopia. « Anaerobic" does not exist on Earth, « anaerobic" cannot exist on Earth. In a decaying environment, the percentage of oxygen decreases, and inversely proportional, the rate of digestion increases.

    The loss of oxygen highlights the presence of SO2. Wherever he comes from, he's important.

    1 Comment

    1. Assuming the wastewater we are talking about is from households, that water is typically conveyed through pipes to a wastewater treatment plant.  In many situations, the wastewater is collected from areas at elevations below the location of the treatment plant.  Those waters are collected in tanks called lift stations.  Those lift stations pump out based on the levels in the tank. If the flow into the lift stations is low, as it often is in the middle of the night, the lift stations don't pump out frequently enough. As a result the oxygen in the water is used up by aerobic (oxygen using) bacteria.  

      Once the water is anaerobic, with little to no oxygen, the anaerobic bacteria become more active. That is the process described previously.  

      I have performed many odor investigations over the years and have found that this condition is almost always the source of significant sulfur odor issues.

  6. Mr. Linton may have gone to college - but his education did not provide him with class or strength of character.  Mr. Ahmed asked a question, and I've always maintained the policy that no question is foolish.  Why did you find it necessary to insult this man instead of providing him with useful information?  Shame on you!

    Ed Baquerizo

  7. Dear Mr. Ahmed, I see you have an undergraduate majoring in chemistry, so unless this is a hypothetical question...designed to test the knowledge of others, I suggest you go back to college and learn something about chemistry.  I am Lippy.  Hear me roar.

     

    2 Comments

    1. Brother actually I rise this question to get the correct answer and many of my friend are working in WWTP plant they face problm so2 is present in areation feed water I rise this question to know how many you are facing same problm if you all facing so2 problem then will I give some useful ideas to slove it I think u don't know they answer so why you said me to go college again I think book and college lectures are our missed thing for example if you missed anythg and lost it and you find it in road or any other place it's your thing same were ever I get knowledge I use gain and understand it because knowledge is my lost thing.

      Hope you understand bro

  8. Many organic compounds have traces of sulfites, including foods we eat..  Many bottled wines for example have sulfites added to prevent spoilage. Those sulfites pass through the human digestive track and end up  in the wastewater as sulfates.  As long as the wastewater stays aerated, oxygen rich, they will stay as sulfates.

    If the wastewater sits in lift stations or in piping connected to pumped sections of sewers too long, the oxygen will get used up by the aerobic bacteria.  At that point anaerobic bacteria will begin breaking down the sulfates in the organic matter and release hydrogen sulfide.  When pumped into oxygenated water in the your wastewater plant, some of the hydrogen sulfide (H2S) reacts with the oxygen in the water to from SO2.  

    The hydrogen sulfide has an even lower odor threshold than the SO2, but both contribute to odors from wastewater plants and the piping and pumping facilities.  Keeping the wastewater from going anaerobic by adding bubblers or chemical oxidizers to the pump stations can help to reduce the odors.