Sign up
Knowledge base

Cost function for the sludge thickener

Cost Functions

The original cost function (A1) for the thickener is as follows:

Función de costos para espesador (1)This function has as variable (x) the diameter of the thickener in feet (ft). To calculate this diameter, a circular structure is considered, therefore:

Función de costos para espesador (2)

Where A is the area of the settler. This area is calculated from the sludge that reaches the thickener, of which the greatest influence is from the settler. For these sludges a concentration of 1% (10 mg / L) is considered, and they are treated approximately at the same time that they are collected in the settler. Additionally, a usual surface load of 20 m / d is taken. With this:

Función de costos para espesador (3)

And replacing:

Función de costos para espesador (4)

This conversion can also be done depending on the solid load like this:

Función de costos para espesador (5)

This value is replaced in the original equation to obtain A2.

Additional modifications to this function correspond to the correction of costs per year, with the CCI ENR index of 9547 of the year 2013, to obtain A3. This function, like the others for sludge treatment, does not require B2 factor of the adjustment for elasticity, this since function A3 already considers the influence of water quality on its costs directly.

According to the above, the following is the function obtained:

Función de costos para espesador (6)

Bibliography

  1. Preliminary Cost Estimation Models for Construction, Operation, and Maintenance of Water Treatment Plants Jwala R. Sharma, Ph.D., M.ASCE; Mohammad Najafi, Ph.D., P.E., F.ASCE; and Syed R. Qasim, Ph.D., P.E., M.ASCE 2013

    Reliable cost estimation of construction, operation, and maintenance (O&M) of water treatment plants is essential for project planning and design. The authors have developed construction and O&M cost models for different unit operations and processes involved in water treatment plants. This paper presents the use of a single cost index to further update construction and O&M costs.

References

Back to top