The Importance Of An OdaLog In Wastewater Collection Testing

Questions that most often come to mind when testing wastewater collection streams are, "where do odors originate from?", "what type of odors are present and in what quantities?" and, "what can I do to resolve these odor/corrosion issues?'". There are many tools available to help answer these questions such as the LaMotte H2S field testing kit for liquid sampling, nitrate residual strips and pH and temperature meters. Through my experience, however, I've found the most important and valuable tool is the OdaLog, a data logger for sampling H2S in the vapor or gaseous phase. 

An OdaLog oddly resembles a yellow soda can but is made of a tough, exterior material. It has a recessed button on top with a stainless steel rod shape resembling an inverted 'U'. Through countless hours of field testing with an OdaLog, I've found they can survive almost anything (except being dropped down the sewer)! The most commonly used OdaLogs are in the H2S detection ranges of 0-200 ppm and 0-1000 ppm. The OdaLog can be set to record data at different intervals. The most common intervals are every 60 seconds and every 360 seconds (the range is from once a second to once an hour). During the time the OdaLog is recording H2S data, it's also recording the corresponding temperature.  

Besides placing an OdaLog in a manhole, the device may be placed in wet wells, clarifiers, inlet scrubber monitoring, headworks facilities, aeration and oxidation ditch processes and bar screens.  After the data has been recorded on the OdaLog it can be downloaded directly to a computer. At that time, you can analyze when and why the H2S increases or decreases. You may also zoom in and enlarge certain time frames to further analyze data. By having the H2S gaseous data over a 7 to 10 day time frame, one can determine how chemical feed rates should be adjusted or if timers need to be used on a second chemical feed pump to eliminate the H2S peaks. The data may even tell you that the addition of chemicals to eliminate H2S is not necessary. 

Graphs of the H2S data can be placed in documents as a wonderful visual aid, helping the everyday individual understand the diurnal pattern of most wastewater collection systems.

Contact Aulick Chemical Solutions for a complimentary survey of your collection system and a recommendation regarding any odor and corrosion control issues. We will be happy to put our data collection tools to use for you!

Eve Sanders

Corporate Sales

Eve Sanders has been in the water industry for 9 years having previously worked in the Odor Control Division for Siemens and for Houston, TX based Altivia. She's served on the Cincinnati State Environmental Programs Advisory Board, which is currently schooling future water and wastewater facility operators.

Eve is also an attorney licensed in Kentucky, Texas and the United States District Court, Southern District of Texas.