SOLIA™ Solar Drying

Renewable Solar Energy Source

Kruger has enhanced the efficiency of solar sludge drying by coupling two well-known processes: air drying and aerobic fermentation.

  • Using solar radiation and the action of an automated windrow turner (SOLIA™MIX), water evaporates from the sludge for subsequent removal from the greenhouse.
  • The SOLIAMIX windrow turner keeps the biosolids aerated and promotes digestion of the biosolids which produces heat to aid the drying process.

The automated SOLIAMIX system deposits the biosolids into windrows. In order to renew the drying surface area and promote aeration, the windrows are turned at regular intervals.

Triangular windrow shaping offers a larger exchange surface area than sludge drying beds for the same amount of greenhouse space, resulting in a faster drying process. Furthermore, a higher quantity of sludge can be stored.

The exothermal reactions occurring during the fermentation process generate a biosolidstemperature increase (50 to 60°C) to promote pathogen destruction.

Optimized Drying Via Ventilation and Circulation

The greenhouse is fitted with two types of air handling systems:

  • Circulation fans are used to provide a homogenous drying atmosphere in the greenhouse
  • Extraction fans are used to remove the moist air and further control the drying process

SOLIA™ Benefits

  • Optimized drying surface with sludge windrow layout
  • 60-80% reduction in biosolids quantity
  • Integrated biosolids storage within the SOLIA process
  • Operational flexibility
  • Optional odor control
  • End product traceability
  • Reduced operating costs
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