Wastewater Calculations - Mathematics and Statistics for the Environment - page 717

Log
Growth

Declining
Growth

Endogenous
Respiration

Residual
Mass

Time

FIGURE 24.8 Bacteria growth curve.

Totalsolids(g)
Biosolidssample(

%Solids = ×100 (2 4.115)

g)

Solids(lb/day)
Biosolids(lb/day)

%Solids = ×100 (2 4.116)

■ EXAMPLE 24.85
Problem: The total weight of a biosolids sample (sample only, not the dish) is 22 g. If the weight of
the solids after drying is 0.77 g, what is the percent total solids of the biosolids?

Solution:

Totalsolids(g)
Biosolidssample(

0.77 g
22 g

%Solids = ×= ×= 100 100 3.5%

g)

24.11.6 b iosolids p umping C alCulations
While on shift, wastewater operators are often required to make various process control calcula-
tions. An important calculation involves biosolids pumping. The biosolids pumping calculations the
operator may be required to make are covered in this section.

24.11.6.1 Estimating Daily Biosolids Production
The calculation for estimation of the required biosolids pumping rate provides a method to establish
an initial pumping rate or to evaluate the adequacy of the current withdrawal rate:

(Influent TSSconc.Eff − luentTSS conc.) × Flow × 8.34

Estimated pumprate = (2 4.117)

%Solidsinslud ge ×× 8.34 1440 min/day