Sewage Pretreatment

Wastewater treatment: Textile hydraulic barriers to improve the purification capacity of wastewater treatment ponds

The installation of hydraulic barriers resulted in increased degradation rates for COD, BOD and nitrate effluents.

 

Summary

A textile hydraulic barrier was developed to improve the purification capacity of sewage ponds, increasing the hydraulic residence time of the wastewater (preventing short-circuiting in the flow) and increasing the sludge age with the help of microorganisms attached to the biofilm carrier. The installation of hydraulic barriers resulted in increased degradation rates for COD, BOD and nitrate effluents. The hydraulic barriers can be installed retrospectively in existing pond sewage treatment plants with comparatively little effort. They thus offer a solution for overloaded plants to which no further ponds can be added.

The treatment of wastewater in ponds is a simple but very effective method with low structural and equipment requirements. Very little control and maintenance is needed, and the elimination rate for pathogenic bacteria, viruses and parasites is high. However, adverse hydraulic conditions can restrict the purification capacity of such systems. Hydraulic short-circuiting occurs if the residence time in the sewage pond is much too short. This results in a very reduced purification capacity. The textile hydraulic barriers which have been developed serve to lengthen the hydraulic residence time in the sewage pond and thus to prevent short-circuiting. The settlement of microorganisms on the additional surface in the pond increases the sludge age.

Textile hydraulic barrier have the following characteristics:

  • They can be installed retrospectively with comparatively little effort
  • The area-specific mass is 2,270 g/m²
  • The individual modules are fitted with pocket-like tunnels both above and below, making it possible to attach floats or weights.
  • The large specific surface of 571m²/m³ increases the inner surface of the pond and introduces biofilm to the system
  • The technical textiles used are flexible and can be draped, and can be produced in a wide range of forms and sizes, allowing further application of these warp-knitted fabrics
  • Wastewater-resistant polypropylene ribbon material

Environmental benefits:

  • Increase in COD, BOD and nitrate degradation rates
  • Reduction of the surface required in a pond sewage treatment plant
  • Wastewater purification process requiring little energy

More Project Informations

Project number:  InnoWatt IW 041198

Project period:  2004 - 2006

Project region:  Germany (Saxony)

Project contact:

Herr Dipl.-Biol. Mählmann

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Source: Federal Ministry for Economic Affairs and Energy (BMWi)