Has Your Wastewater Treatment System Been Designed for Unusual Weather Patterns?

At the end of 2021, Bellingham, Washington, experienced some of the heaviest rainfall the city has seen. The city received close to two feet of rain in just three months. A blizzard hit Hawaii’s mountains, while low-lying regions in Oahu saw up to ten inches of rain, and Maui got more than a foot over just a few days.

Things haven’t eased up in 2022. The East Coast recently experienced a Nor’easter that left some areas with more than two feet of snow. New York City had already experienced too much water, with the remnants of September’s Hurricane Ida dropping more than six inches of water, resulting in massive flooding and sewage system failures.

When Hurricane Ida hit New York City, the city’s sewer system was designed to handle less than two inches of rain per hour. It led to stormwater backing up into people’s homes and subways. Is your wastewater treatment system set up for unusual weather patterns?

Weather Patterns Are Changing

Weather patterns are changing, and areas with older stormwater systems see the effects. When it rains or snow melts, the excess water goes into storm drains. From there, it creates several problems. With some stormwater systems, the water flows into channels that go to area streams, rivers, and other bodies of water.

Close to 800 cities and towns have combined sewer systems. A combined sewer system is one where stormwater and wastewater are collected into the same system and go to a wastewater treatment plant for processing. With both of these designs, excessive rain causes significant issues.

If there are heavy rains, the channels for stormwater runoff may fill up and have no more room. That water has to go somewhere. It ends up in people’s houses and creates rivers in the streets. All of that flooding causes costly damage, but it also puts people’s lives in jeopardy. As the water levels rise, anyone trying to drive to safety can get caught up in it.

During Hurricane Ida, dozens of people died in vehicles overtaken by floodwaters. In NYC, more than 800 people had to be rescued from the city’s subways. Close to a dozen people were killed when their basements flooded.

With a combined sewer system, the stormwater and wastewater come in too fast for the plant to handle. Some of the untreated sewage must be released to prevent a catastrophe. Bacteria and other contaminants end up in rivers, lakes, and oceans, where people can become ill if they eat shellfish from the contaminated area or swim in it.

It’s impossible to know in advance if unusual weather patterns will hit your municipality. That’s a leading reason why every wastewater and water treatment facility must be designed to withstand flooding. How do you do that when you can’t tell when a blizzard or heavy rainfall will happen? Having a well-designed stormwater management system is essential.

Components in a Stormwater Management System

Stormwater pump systems help push the water away from low-lying areas to prevent flooding. Sometimes, cities are on a slope, so gravity helps move water downhill to a water source. Other regions are at sea level and experience a higher level of flooding. It’s important to make sure this water is pumped to ponds and other water sources. Stormwater pump stations must be designed to move water quickly from one area to another.

Steps to Take to Prevent the Release of Untreated Sewage

What can you do to prevent a worst-case scenario? Start by asking how old your system is? If your wastewater system was designed 40 years ago and the population has tripled, you may not be ready for heavy flooding, especially with a combined sewer system.

Go through your plant and look at the capacity and rates for your pumps, rakes, screens, and other wastewater treatment equipment. Is your system designed for heavy floods? What can you upgrade to get it ready?

The EPA has several rules that apply to combined sewer systems. If your equipment is older, these nine areas must be addressed, and it’s easy to do this through wastewater treatment upgrades.

  1. Routine maintenance – All equipment should undergo routine maintenance and cleaning. To make this easier, look for low-maintenance equipment that’s above the water for easy access. Grit removal systems filter out grit, such as sand and gravel, to help prevent wear and tear on the components.
  2. Storage system capacity – If your stormwater system has a screw pump, you need to make sure that a wet well is large enough to fit the volume of water collected during a heavy storm. Have secondary ponds or storage areas to collect the water until your plant can handle more stormwater. Planning for more than is required is one way to ensure you have enough capacity.
  3. Maximized flow rates – Purchase equipment that adjusts to increasing flow rates to prevent issues. For example, a Type C Enclosed Screw Pump can move anywhere from 540 gallons per minute to more than 35,000 GPM. A design like this ensures that the water moves quickly, even if there’s far more stormwater than usual.
  4. No combined sewer overflows when it’s dry – When it is dry, you shouldn’t have any overflows. If you’re still experiencing overflows in dry weather, it’s time to take a closer look at the amount of wastewater coming into your plant from different neighborhoods. Is a resident running water all day and night? If so, the district needs to look at why that’s happening. Is there an issue with leaking pipes or seals anywhere?
  5. Proper screening of floating and solid waste – Screens and trash rakes should be used to remove any fecal waste and trash. With many energy-efficient models available, your upgrade can save money on energy bills.
  6. Notification system to alert communities of overflows – You need to alert the public when there is an overflow. Have a plan in place so that the proper employees know how to get the word out to everyone. Local newspapers may not be enough. You might need to send out a mailing and post on social media.
  7. Monitoring the impacts of overflows – Once there is an overflow, it’s your responsibility to monitor any effect it has on the environment. Work with area agencies to ensure this is done on a timely basis.
  8. Steps to prevent pollution from overflows – If you experience a surge, it’s crucial to research why it happened. You have to take preventative measures to keep it from happening again for the same reason. If you experienced an overflow because your pumps couldn’t handle the volume of water, upgrade the pumps as a preventative measure.

When is the best time to upgrade your equipment? It’s best to go over your combined sewer system’s design before the unexpected occurs. It gives you time to make upgrades as you can. Even one small step can prevent a catastrophic overflow of sewage into local bodies of water.

Plus, upgrades help reduce your operating costs over time. You might need to spend money to complete upgrades, but the savings in energy end up paying for those upgrades in very little time. Lakeside Equipment can go over your current design and help you find ways to maximize your plant’s capacity while saving you money. Call us to learn more.