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The Ultimate Guide To Good Wastewater Odor Control: Part Two

Odor control is something most of us never give a second thought to until it’s no longer working as expected. Once we’ve been confronted by the sulfurous smells that can come from untreated wastewater, it’s clear how much of a difference our usual treatment processes really make!


The thing with odor control is, it’s an ongoing battle. Whether it’s from the collection system or the plant itself, odors are likely to show up at some point and cause a literal and figurative headache. Imagine trying to sell your home in a neighborhood that is starting to smell of untreated sewage - you can bet it will have an impact on how quickly you find a seller.

This puts a lot of pressure on treatment plants and local governments to keep these systems running in tiptop shape, all the time. Something easier said than done.


There are several ways to take on odor control when it comes to untreated wastewater. In a recent post, we brought you part one of the guides to good wastewater odor control, which you can read here. Here in part two, we’ll be talking about liquid phase treatment options that are considered to be ideal for wastewater collection systems and more.


With that being said, It’s difficult to directly compare vapor-phase and liquid-phase treatments to each other. While they’re generally grouped into the same category, there are some key differences and even places where they can complement each other to lead to a cleaner, safer end product.


Keep reading as we dive deeper into the various liquid-phase technologies that are available for better wastewater odor control - what they are, how they work, and what are the best options for the future?


Introducing Liquid-Phase Technologies For Odor Control


If you’re unfamiliar with how liquid-phase technologies work, the easiest way to think about it is that they reduce odors by adding chemicals to the wastewater to prevent the build-up of smelly compounds. What’s worth noting here is that this approach is commonly used in wastewater collection systems more than it is used in actual treatment plants. You may even consider it a pre-treatment.


When it comes to liquid-phase treatment methods, they’re driven mainly by the rate of wastewater flow and how many contaminants are still present in the liquid stage. This will also dictate what kind of chemicals are used and the strength of the concentrations needed to achieve a pollutant-free result.


This part is especially important because not all contaminants can be treated by the same chemicals. Using liquid-phase technologies means it’s easier to inject what’s needed when it’s needed instead of using the same costly chemicals over and over with little results. This is expensive, and can even become dangerous if elevated levels persist over time.


There is another advantage to using liquid-phase technology, namely the ability to reduce corrosion. Corrosion in the wastewater collection system is a recurring issue for many municipalities that can require costly maintenance. In liquid-phase treatments, compounds like hydrogen sulfide are trapped in the liquid state which makes them less likely to settle on pipes and infrastructure and cause lasting or expensive damage than they would be if they were vaporous.


And that’s not all. Liquid-phase treatment is multi-pronged and can tackle odors in several different ways. We’ve already mentioned how smelly compounds are trapped up in liquid chemicals to prevent them from becoming airborne vapors, but when set up correctly liquid-phase treatment also uses odor release areas like:


  • Manholes

  • Re-pump stations

  • Valves and vents


Without proper measures in place, these odor release areas can quickly become a nightmare. Smelly bacteria can build up in the biofilm of the sewer and other collection areas to become a concern to general public health.


Now we’ll take a closer look at the different odor control technologies falling into the liquid-phase treatment category:


Approach #1: Iron Salts


When treating odiferous wastewater, iron salts are one of the liquid-phase methods used to reduce bad smells. Iron salts are used mainly to dissolve sulfides present in the collected wastewater. These ferric salts oxidize a large amount of the sulfides, while the remnants are simply transported downstream to the treatment plant for further processing.


Iron salts are typically administered via a pump system upstream of the treatment plant, with the dosage being set based on the rate of flow, the concentration of dissolved sulfides, and more. The dosage can differ based on the season or on a variety of other factors.


One thing worth noting is that the sulfates and ferric irons that are present in this type of treatment can be highly hazardous to human health, and even to the infrastructure. Solutions made up of iron salts need to be stored in special double-walled tanks and be transported via reinforced piping. Employees also need to wear protective gear including goggles and gloves to handle any of the equipment or chemicals.


Despite this hazard, iron salts are typically used because they’re affordable. Iron salts are purchased cheaply from the steel industry where they are a by-product. At the same time, they need to be used in higher concentrations than other chemicals.



Approach #2: Oxidizing Agents


Another method of liquid-phase control that makes use of chemical input to oxidize wastewater and reduce bad odors. By injecting strong chemicals into the collected wastewater, odorous compounds are treated and smells are largely dissolved.


The type of oxidizing agent used will depend on the contaminants present in the wastewater that is in need of treatment. Based on the quality of the water, the selected oxidizing agent will determine which chemical reaction will take place to remove bad odors.


Some common examples of oxidizing agents include:


  • Oxygen

  • Hydrogen peroxide

  • Nitric Acid

  • Sulfuric Acid

  • And more


The oxidizing agents used in this approach to odor control can also be hazardous, especially as hydrogen peroxide is one of the most commonly used chemicals. Similar to iron salts, special additional measures need to be taken to keep the plant and employees safe.


Approach #3: Anthraquinone


Anthraquinone is a liquid-phase treatment method that uses a specific chemical compound in order to reduce bad odors caused by sulfides. Unlike many of the other chemicals used in liquid-phase treatments, Anthraquinone is actually non-hazardous.


There are several interesting things to know about this approach. Anthraquinone works by encouraging a metabolic process by which sulfide-reducing bacteria are placed into an anaerobic state. This interrupts their ability to develop and ultimately create bad odors.


With that being said, Anthraquinone won’t be effective against every type of contaminant and is best used in conjunction with another type of treatment for best effects.


Approach #4: The In-Pipe Solution


There is another solution available, one that makes use of no expensive chemicals and actually helps treatment plants and local governments save time and money over the long term. How? By going back to the source.


What if you could find a scientifically proven way to eliminate odor at its source without running around playing Whack-a-Mole throughout your system? Believe it or not, there is a better solution than expensive scrubbers and filters or dumping potentially toxic hydrogen peroxide or calcium nitrate into your system.


Odor problems can occur in multiple areas in the process, but if you attack the problems at the point where they germinate you’ll have much better success at preventing issues later in the system. It’s all about being proactive instead of reactive.


In-Pipe Technology’s solution is designed to fight fire with fire, eliminating odor problems at their source with a proven bioscience solution that targets the cause of the odor and destroys it.


Don’t wait to fight Hydrogen Sulfide (H2S) and foul sewer odors after they have formed, go after them at the source: the sewer biofilm. No harsh chemicals. No expensive scrubbers or other equipment. Just a biological battle in which the bad bacteria loses, and the source of the odor is washed away – well before you have to deal with it at a lift station or the treatment plant - and before it stinks up your community.


If odor-causing bacteria are stuck inside a pipe, they likely have plenty of nutrients to keep it going. To combat this, In-Pipe will continually dose its proprietary mix of bacteria into the affected area, which will get to the nutrients three times as fast to effectively starve the bad bacteria. The result is that the odor-creating bacteria die off and dissolve into the wastewater.


With the added benefit of being good for the environment, providing top-notch service, and being quick and easy to get started with, In-Pipe’s innovative solution to persistent odor problems stands out in the market because it takes care of the problem at its source. Cities are looking for inexpensive, long-term, green solutions and In-Pipe will make it possible for you to fix it and forget it.


Contact us today to find out more about how we can help you to take care of those pesky bad odors by building you a customized solution: https://www.in-pipe.com/odor-control

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