Dredging with BioSpikes® 4000 at a municipality treatment plant increased the plant’s lagoon capacity through effective sludge reduction and postponed a $600,000 project. 
  
Benefits 

  • A 28% improvement in sludge reduction levels in the treated area
  • An increase in lagoon treatment capacity from 9% to 35% in the treated area
  • Defers a $600,000 dredging project without associated negative impacts on effluent quality 

Background 
A municipality was concerned about potential problems from years of poor sludge reduction, resulting in sludge buildup in its wastewater treatment lagoon. The 2.5 hectare (6-acre) lagoon is 3.4 m (11 ft.) deep, and sludge levels ranged from 2.4 to 3.0 m (8 to 10 ft.) throughout the lagoon, severely limiting treatment capacity. Looking for alternatives to a $600,000 dredging quote, the municipality teamed up with Novozymes Biologicals to evaluate BioSpikes® 4000. 
  
Application 
The lagoon is aerated by two floating mixers in the front end. BioSpikes® were added to an area of the lagoon with significant sludge buildup, and lacking sludge reduction. Sludge measurements were performed monthly for 6 months and compared to the untreated control area. 
  
Results 
After 60 days the sludge levels were reduced in the treated area by 28% – 0.87 m (2.8 ft.), while the sludge levels in the untreated areas increased by 19% – 0.47 m (1.5 ft.). The drop in sludge levels led to an improvement in operating capacity from 9% before the trial to 35% after the trial – a 289% increase. 
  
Conclusion 
The addition of BioSpikes® 4000 to the municipal lagoon system successfully deferred dredging and increased treatment capacity by improving sludge reduction. The municipality is planning to scale up the application and treat a much larger area. 
  
  
Fig. 1. The application of Novozymes BioSpikes resulted in a 28% improvement in sludge reduction in the treatment area over 60 days.