Microscreening costs

Introduction Microscreening Process Design Criteria Backwashing Design oe Microscreens Energy and Costs Design Example Nomenclature Reeerences Appendix... 

The microscreens construction and operation and maintenance costs (1979 dollars, Utilities Index = 257.20) are illustrated in Figs. 3 and 4, respectively (9). To obtain the values in terms of the present 2004 US dollars, using the Cost Index for Utilities (Appendix A), multiply the costs by a factor of 506.13/257.20 = 1.97 (20). The costs are based on the following assumptions ... 

The biomass concentration in the microscreen backwash is low. We have established however that centrifugation at 2800 g appears to allow concentration up to 2 or 3% dry solids, or by about a factor of ten. The pasty cake obtained could be used directly as an animal-feed additive if there were a market nearby, or could be dried for shipment. Centrifugation of microscreen backwash is a relatively low cost operation we estimate that it would add 10,000 to the capital cost and 2 hp to the power requirement of the estimates in Table 1. 

Revolving drum filter (microscreen), rotary screen mechanism, motor and drive. FOB cost 250000 at screen area = 15 m with n = 0.83 for the range 1-950. L-i-M = 3-3.2. 

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