Comparison with Traditional Methods

This cost comparison graph has been produced to demonstrate the potential cost and CO₂ emission reduction achievable by introducing sludge treatment in reed beds as opposed to traditional disposal routes.
The comparison is based on a sludge production of 1,000 tonnes of dry solids, equivalent to a population of 50,000.

Cost reduction
The cost of designing, constructing, operating, maintaining and taking sludge to agricultural land from a Sludge Treatment Reed Bed is compared to a traditional sludge disposal route.

The traditional route is based on adding polymer and thickening with belt pressers on the sewage treatment works, transportation to a sludge centre, dewatering in centrifuges adding polymer and finally taking sludge to agricultural land. All costs for designing, constructing, operating, chemical usage and transport are included.

All numbers are displayed as an accumulated yearly Net Present Value (discounted cashflows).

In some cases in Denmark, Sludge Treatment in Reed Beds have proven themselves so well, that existing new centrifuge installations have been taken out and replaced with reed beds.

CO₂ emissions
The same comparison has been made for the emission of carbon dioxide.
The calculation of emissions is based on the production of CO₂ involved with producing power for running the two plants, and includes the emissions from trucks transporting the sludge.