Industrial Lagoon Solids Reduction Case Study: 42% Reduction Without Dredging
Overview
- 1,267,738 pounds of solids destroyed
- 42% solids reduction achieved
- 571 pounds of solids reduced per pound of product applied
- Dredging avoided while preserving anaerobic biology
- Improved lagoon performance and gas production observed
A large industrial wastewater facility was experiencing severe solids accumulation throughout its lagoon treatment system, compromising both treatment performance and anaerobic digestion efficiency.
The facility included two covered anaerobic lagoons, followed by three open aerobic lagoons and a finishing pond.
At the anaerobic stage, accumulated solids had become so severe portions of the lagoon surface were described as nearly walkable. Flaring capacity had also declined dramatically, dropping from 12 hours per day to only two — a sign that anaerobic digestion performance had deteriorated.
Conventional mechanical dredging was considered, but operators recognized dredging risked disrupting the established anaerobic ecosystem supporting treatment performance.
Instead, the facility implemented biological sludge reduction using Bio Dredger®.
A total of 2,370 pounds of product was applied during treatment.
The result was destruction of 1,267,738 pounds of accumulated solids — a 42% reduction.
Restoring Lagoon Performance Without Mechanical Dredging
Rather than physically removing solids, treatment targeted accumulated organic material within the anaerobic and downstream aerobic lagoon system.
Performance improvements were observed not only through solids reduction but through restored process activity, including improved flaring performance and downstream treatment response.
This case achieved a solids destruction ratio of 571 pounds of solids per pound of product applied — within the typical performance range observed in lagoon applications.
COD Response Confirmed Active Solids Breakdown
Drylet monitored Chemical Oxygen Demand (COD) throughout the treatment period at seven sampling points spanning influent, anaerobic digestion stages, aerobic lagoons, and finishing pond discharge.
A temporary rise in COD at the second anaerobic lagoon effluent indicated active breakdown of accumulated solids.
This response is consistent with decomposition of fats, oils, proteins, and other settled organic material releasing soluble and particulate COD for downstream biological treatment.
Rather than signaling treatment upset, the response reflected mobilization and digestion of previously accumulated solids.
Why Avoiding Dredging Mattered
Mechanical dredging would have removed solids but also risked disrupting the anaerobic biological system already established in the covered lagoons.
Avoiding dredging helped preserve:
- Existing anaerobic digestion activity
- Methane generation potential
- Lagoon treatment stability
- Capital and cleanout costs
- Downstream aerobic treatment performance
For facilities considering expansion or cleanout, optimizing biology before dredging may offer an alternative to mechanical lagoon dredging.
Operational Takeaway
This project demonstrates that severe industrial lagoon solids accumulation may be addressed biologically without immediate mechanical dredging, while preserving anaerobic system function and restoring treatment performance.
For facilities facing solids buildup, declining gas production, or reduced lagoon capacity, biological optimization may provide an alternative to disruptive capital interventions.
FAQ
Can biological treatment reduce solids in industrial lagoons?
Case studies have shown biological treatment can reduce accumulated solids while supporting treatment performance.
Can biological treatment replace dredging?
In some systems it may delay, reduce, or help avoid dredging, depending on solids loading and lagoon condition.
What does a rise in COD during treatment indicate?
Temporary COD increases can indicate mobilization and breakdown of accumulated organic solids.