23 JULY 2003
Prepare equipment design layout (i.e., engineering drawing and details) and
design analysis. The design analysis should include a detailed description of the
dewatering process and supporting calculations.
Prepare project equipment specifications from guide specifications.
DESIGN EXAMPLES. Following are three examples that follow the design
approach described in Paragraph 5-1 of this chapter and design calculations presented
in Chapter 3. The design criteria presented in these three examples are primarily based
on information presented in Paragraph 2-4 and other referenced paragraphs of Chapter
Design Example Number 1. This is a design example with supporting
calculations for sizing a sludge-dewatering system.
Assumptions. The following assumptions and criteria are used for the design
of the sludge-dewatering system.
The characteristics of the sludge stream are given below.
Design liquid sludge flow = 37,850 L/d (10,000 gpd)
Concentration of solids
Specific gravity of feed
The minimum dry solids allowed in the sludge cake will be 30% by weight.
5-2.2.3 A fixed-volume recessed plate filter press will be used for this example.
Typical ranges of design criteria for this type of filter press are presented in Paragraphs
2-3 and 2-4.
5-2.2.4 This example assumes that treatability testing has been done and the
following design data were obtained.
5-220.127.116.11 Sludge Cake Characteristics.
32 mm (1.25 inch)
1280 kg/m3 (80 lb/ft3)
Wet cake density
5-18.104.22.168 Optimum Chemical Conditioning.
Lime dosage (CaO)
10% by weight of dried solids
Ferric chloride dosage (FeCl3) =
5% by weight of dried solids