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WaterOperator.org Blog

Articles in support of small community water and wastewater operators.

Focus on Chemical Feed Control

Focus on Chemical Feed Control

Chemical dosing at the water treatment plant is a critical, but often underrated step in producing safe drinking water. Historically, process control points have focused on the hazards present in incoming source water - with emphasis on the filtration and disinfection steps to minimize microbial risks. But while many hazards do indeed enter the plant with the raw water, it is just as important to identify the multiple risks associated with treating this raw water.   

One significant hazard in the treatment of water at the plant is overfeeding, resulting in discoloration, strong smells, or health hazards at the tap. Some of the most common root causes of overfeeding problems are pump or equipment failures, variations in water temperature, and source water characteristic fluctuations, to name just a few. In addition, bringing new technology online can sometimes trigger an event as well. This is why it is important to carefully document chemical handling and feeding information specific to your system on forms such as this one from the New Jersey Department of Environmental Protection.  

It is also essential to be on top of monitoring, chemical feed math skills and feed pump maintenance in order to correct situations as they arise (not to mention how to use activated carbon or sulfur dioxide to correct water quality issues). This resource from MASSDEP lists immediate action levels for water treatment plant chemicals. This tool from Missouri Rural Water can help you quickly size a chemical feed pump. This NCSE Tech Brief can help you calibrate a liquid feed pump. In addition, overfeed alarm systems are another solid choice for avoiding this problem. 

Finally, if and when an overfeed occurs in your system, prompt reporting can help speed up remediation. The Minnesota Department of Health provides this emergency response guide to its community PWSs in the case an event is affecting functionality or water quality. Learning who to call for help sometimes is the most difficult step in an emergency response situation, so preparing ahead can save you critical time and effort!  

*WaterOperator.org staff member Phil Vella contributed to this post.

Featured Video: Wastewater Microbiology

If you're a wastewater treatment operator, you know your "bugs" are what helps make the whole thing go. Most wastewater treatment plants rely on the action of various microscopic creatures to clean and break down the waste at their plant. And these bacteria, protozoa, and other life forms do more than just treat your wastewater. Correctly identifying and counting the "bugs" in your system can also give you an idea of what's going on in your plant, like what nutrients or other levels might be high. This can then give you ideas on what other tests or treatments need to be run to mitigate any problems before they get out of hand.

What if you want to be friends with your bugs, but you don't know how to start? This video could be a good first step. In this eight-and-a-half minute video, you're introduced to the basic kinds of microbes found in a wastewater treatment plant. This includes microscope video of several varieties of critter, and discussions of their significance as indicator organisms.

If you'd like to learn more about your tiny wastewater treatment buddies, go to our document database and type "wastewater microbiology" (without the quote marks) into the keyword search field. Then click "Retrieve Documents." To see what operator training may be available near you, visit our calendar and select your state using the drop-down menu options.