How Do You Know If Your Lagoon Needs Dredging? 7 Signs

A lagoon can look perfectly normal from the surface while a very different story is developing at the bottom.  Over time, solids from wastewater treatment processes settle and accumulate as sludge and sediment. Some accumulation is expected, but as that material builds up, it can reduce the lagoon's available capacity and affect how effectively the system operates. The EPA notes that accumulated sludge in wastewater lagoons needs to be periodically removed.

The challenge is knowing when normal accumulation has become a problem. So, how do you know when your lagoon may need dredging? Here are seven signs that it may be time to take a closer look.

1. Your Lagoon Is Losing Usable Capacity

One of the biggest concerns with sludge accumulation is the gradual loss of available lagoon capacity.  Sludge settles at the bottom, taking up space that would otherwise be available for wastewater storage and treatment. Because the buildup happens below the water surface, it may not be obvious just by looking at the lagoon.

As accumulation continues, the lagoon has less usable volume for incoming wastewater.  This can become especially important for facilities that experience changes in production, wastewater flow, or seasonal conditions. A lagoon that once had sufficient capacity may eventually have less flexibility to handle changing operating conditions.

2. Sludge Is Building Up at the Bottom

Sludge accumulation is a normal part of many lagoon systems. The problem is allowing it to continue without monitoring how much material has accumulated.

The EPA identifies several factors that can affect sludge accumulation and recommends methods such as sludge judging and core sampling to determine the volume and mass of accumulated sludge.

Instead of waiting until buildup becomes an operational problem, facilities can periodically evaluate sludge depth and track changes over time.  This provides a better picture of what's happening beneath the surface and can help with planning future maintenance.

3. Treatment Performance Is Changing

A lagoon's ability to treat wastewater depends on maintaining the conditions the system was designed to provide.  Excessive solids accumulation can reduce active treatment volume and affect lagoon performance. EPA technical guidance notes that sludge accumulation can decrease active treatment volume and negatively affect lagoon performance.

If your facility begins noticing changes in treatment performance, it may be worth evaluating whether accumulated solids are contributing to the problem.

Dredging isn't automatically the answer to every treatment issue, but understanding the condition of the lagoon can help determine whether accumulated sludge is part of the equation.

4. Your Lagoon Requires More Maintenance

Is your team spending more time dealing with problems around the lagoon?  Increasing maintenance requirements can be another reason to evaluate what's happening below the water's surface.

As solids accumulate, they can create additional challenges for lagoon operations and equipment. Depending on the system, accumulated material may interfere with pumping or other processes used to manage wastewater.  Rather than addressing the same operational problems repeatedly, it may be worth determining whether sediment and sludge accumulation are contributing to them.

5. Water Levels Are Becoming More Difficult to Manage

A lagoon with less available capacity has less room to accommodate changes in incoming flow.  That can matter when wastewater volumes increase or when environmental conditions introduce additional water into the system.

The issue isn't necessarily that the lagoon is visibly "full." The concern is how much of its original usable capacity remains after years of sludge accumulation.  Understanding that difference is important when evaluating whether dredging should be part of a facility's maintenance plan.

6. Sediment Is Affecting Lagoon Operations

Not all accumulated material behaves the same way.  Depending on the wastewater characteristics and the lagoon itself, settled material can include organic solids, inorganic material, sand, and other precipitates. As these materials accumulate, they can become more difficult to manage through conventional pumping alone.

Dredging provides a way to remove accumulated material from the lagoon without necessarily requiring the entire system to be drained.

7. You're Planning for Future Capacity

One of the best reasons to evaluate lagoon conditions is simple: you don't have to wait until there's a problem.  If your facility knows that sludge has been accumulating for years, this may be the right time to determine how much material is actually present and what options are available.

Planning ahead can give facility managers more time to evaluate:

• Current sludge depth
• Available lagoon capacity
• The volume of material that may need to be removed
• Dredging methods
• Dewatering requirements
• Solids handling and disposal
• Project scheduling and site logistics

The more information you have before a project becomes urgent, the more options you may have for planning the work.

What Happens During Lagoon Dredging?

Once a lagoon has been evaluated and dredging is determined to be appropriate, the next step is developing an approach based on the site's specific conditions.

Lagoon dredging involves removing accumulated sludge and sediment from the bottom of the lagoon. Equipment and methods can vary depending on the lagoon's size, depth, material characteristics, access, and project requirements.

For many projects, the dredged material also contains a significant amount of water. That means removing the material is only part of the project.

The next question becomes: What happens to the material after it is dredged?

Dredging and Dewatering: Managing the Material After Removal

Dewatering can be an important part of a lagoon dredging project.  Instead of handling large volumes of water-heavy sludge, dewatering can separate water from solids and reduce the volume of material that ultimately needs to be managed.

Depending on the project, different technologies may be considered, including:

• Centrifuge
• Filter Press
• Belt Press
• Geotube

The appropriate approach depends on the characteristics of the material, the site, project goals, and other factors.

This is why lagoon dredging shouldn't necessarily be viewed as a single service. Dredging, dewatering, and solids management can work together as part of a comprehensive approach to lagoon maintenance.

How Can You Determine If Your Lagoon Needs Dredging?

There isn't one universal schedule that determines when every lagoon needs to be dredged.

Instead, the condition of the lagoon should be evaluated based on factors such as sludge accumulation, available capacity, system performance, wastewater characteristics, and operational needs.

Regular monitoring can help facilities understand how quickly material is accumulating and identify when removal may be appropriate. If you're unsure how much sludge has accumulated in your lagoon, a professional evaluation can help provide a clearer picture of the conditions below the surface.

Plan Your Lagoon Dredging Project With Handex

A lagoon doesn't have to be visibly overflowing with sludge before it deserves attention.

By monitoring sludge accumulation and understanding how much usable capacity remains, facility managers can identify potential problems earlier and plan maintenance before buildup becomes a larger operational challenge.

Handex provides industrial dredging and dewatering services for lagoons, pits, ponds, and other industrial applications. Our team can help evaluate project requirements and develop an approach for removing and managing accumulated sludge.

Need to determine whether your lagoon is ready for dredging? Contact Handex to discuss your project and find the right approach for your facility.

Contact Handex today!