Nowhere To Hide

I've been in the wastewater business for 30 years - 15 in municipal management and operations, and 15 with a rural water organization. I've seen populations and communities continue to grow and expand, and subsequently, the need to treat wastewater means more facilities near homes. The old saying in odor control, "out of sight, out of mind", doesn't work anymore. Years ago, wastewater treatment plants were located far away from communities, and the odor was only a problem for those at the facility. Today, with new home developments booming and urban growth extending into even the most remote areas, odor has become an issue in some communities. Smell is one of the most sensitive of our senses, and people can readily detect almost any odor in their surroundings. Now that many wastewater treatment plants are being surrounded by neighborhoods, the potential for complaints, bad community relations, and hard feelings is immense -- and growing. 

Once communities become aware of an odor event, regardless of how small or short in duration, complaints can be triggered. Therefore, it's becoming essential for wastewater professionals to manage and control odors before the neighbors notice. Odors aren't simply an issue of bad public relations. The same compounds that create these odors can also corrode and damage treatment plants and collection systems. It's important to be proactive to address corrosion, to prevent negative images of facilities, and to avoid a crisis by allowing time to implement the appropriate solution. Most wastewater professionals are faced with learning all they can about odor control and finding someone who can solve their odor control problems effectively. 

Where They Start 

Wastewater-related odors typically develop in the liquid phase early in the treatment process during collection and transportation to the plant. While traveling through sewer lines, wastewater can become anaerobic (the dissolved oxygen can become depleted) as a result of the bacteria commonly found in wastewater. Under anaerobic conditions, certain types of bacteria generate hydrogen sulfide (H2S) as a byproduct. Unfortunately, H2S, because of its composition, easily escapes from wastewater and moves into the air -- the vapor phase. H2S is recognized by its strong, offensive, rotten-egg odor. 

In addition to creating odor along sewer lines and at lift stations, H2S is released into the air in areas such as wet wells, equalization basins, headworks, grit chambers, primary clarifiers, and biosolids processing areas. H2S isn't just an odor issue. It can also cause severe corrosion problems and toxic conditions within wastewater conveyance and treatment facilities. Other odorous compounds such as mercaptans and organo-sulfide compounds are found in wastewater systems where H2S problems exist. Together, these compounds are usually considered "sewer odor" compounds or "organics." Their effect on odor conditions is secondary to H2S, but it must be considered. Each waste collection and treatment system is unique, with complex and variable conditions, which can prove challenging when selecting the appropriate odor control solution. Understanding the makeup and sources of odor can help utility personnel better manage odors effectively. 

Odor Control Services 

For many communities, especially those experiencing incredible growth, keeping up with odor control can seem unmanageable. By outsourcing the odor management function to full-service odor-control experts, utilities can control personnel and labor costs, meet the demands of a growing community to reduce customer complaints, and manage costs associated with odor control. A service contract can involve a wide range of scenarios, but the most comprehensive service offerings have the vendor take responsibility for all odor-related problems. Under a single contract, a vendor would respond to all odor complaints, investigate the associated problem(s), and suggest an appropriate solution to each problem. At times, this could involve operations or treatment process changes, specific pretreatment activities, or even the addition of equipment. There are no capital costs to the utility as all products and services are provided on a consumption or time basis. The contract, based on performance, encourages implementation of the most efficient solutions. 

Start Early, Engage Experts 

Most wastewater treatment systems require a variety of technologies, so there are no easy answers to odor control. Faced with ever-expanding wastewater treatment networks, new neighbors, and ever-present budget constraints, utility managers are challenged to effectively manage wastewater odors. If not managed correctly, out of control odors could cause a negative image of the treatment facility, or worse yet, a public relations crisis with neighbors contacting elected officials and media about their odor plight. It's essential that utility managers start early, do their homework, and engage industry experts to effectively manage odors. A good example is a sanitation district sending their wastewater to a regional wastewater plant that has strict H2S limits and also had several odor issues through their system. They consulted with technicians from Aulick Chemical Solutions for help. Aulick designed and strategically located complete Nitra-Nox chemical feed systems to place in several locations throughout their collection system. To date, this district meets H2S limits, and there have been no odor complaints reported since the product has been introduced.

If your company or utility have H2S or odor problems, call or email Aulick today to request additional information and schedule a trial - info(at)aulickchemical(dot)com, 859-881-5422. 

Keith Bevins

Water & Wastewater Treatment Consultant