Water Quality Month Spotlight: The Domino Effect of Water Efficiency
As you progress towards your water efficiency goals, have you considered the downstream effects of reducing water usage? We’re addressing what emerges from the pipe because water efficiency cannot be achieved without the treatment of wastewater.
It’s crucial to approach water efficiency holistically, as reducing water usage in production can have cascading consequences for your facility. While achieving a 50% reduction in water usage or attaining best-in-class water-use ratios is great, there’s a risk of tunnel vision. Focusing solely on reducing water intake without considering the challenges downstream can lead to unforeseen complications.
The Domino Effect of Water Efficiency
When you reduce water usage upstream in your production facility, you inevitably generate wastewater that is more concentrated in pollutants. The less water you use, the less water you discharge, but since pollutants remain the same, the wastewater becomes more concentrated. This increase in concentration requires a different approach to wastewater treatment than what you were previously doing.
The problem arises when you do not plan for this, leading to potentially significant consequences in your wastewater treatment that can ultimately impact your production. Whether you’re treating wastewater onsite or discharging it to the sewer, it’s essential to consider the downstream effects of water efficiency.
Navigating the Challenges
If you’re discharging to the sewer, you could encounter issues with your utility. Despite reducing the volume flowing down the drain, the increased concentration of pollutants poses challenges for downstream centralized wastewater treatment facilities. Your utility anticipates a specific concentration of pollutants from your production processes, and likely you will have a discharge permit specifying these limits, so they may request dilution or the addition of cleaner water to your wastewater before discharge. In some cases, they might even require you to transport the wastewater offsite to another facility or for land application instead of sending it to the sewer as before.
If your facility already has an existing wastewater treatment system, you’ll need to adjust its operation to handle the higher concentration of waste streams. This adjustment may lead to increased energy consumption, higher sludge production, or more chemical addition, and in turn, increased costs, especially if you have an aeration system. In some instances, the existing aeration system may no longer function effectively, regardless of how much energy input is increased.
You may now require an anaerobic digester that’s more adept at handling higher concentration wastewaters. However, due to the smaller volume, your typical anaerobic digester may not be the best solution. These systems typically make the most financial sense with volumes upwards of 100,000 gallons per day; lower volumes would not make this the most cost-effective solution. The traditional approach to addressing this issue has been to simply dilute the concentrated wastewater by adding cleaner water back in. While this increases the volume and decreases the concentration of your wastewater, it negates all the water efficiency progress you made upstream.
Another option for managing these high-concentration streams is to utilize offsite alternatives such as land application or incineration. The implications of these alternatives are significant, ranging from environmental concerns to business risks and costs.
Land application and incineration degrade the land and watersheds by dumping concentrated wastewater into landfill pits or burning it in the case of incineration. Both methods also release large amounts of greenhouse gas emissions as the pollutants in the wastewater break down. Utilizing either alternative requires offsite hauling of the wastewater, which is not only costly but also poses pollution risks to your business if something happens on the road. There’s a risk of spillage, reputational damage, and in cases where the hauling company is unable to accept your wastewater, production shutdowns may occur.
So, you find yourself stuck between a rock and a hard place. How can you reduce water usage in your production while still maintaining efficiency, cost-effectiveness, and value in your wastewater treatment?