Equation 1
$$
1 - {N \over {N_0 }} = {{\left( {{N \mathord{\left/
{\vphantom {N
\kern-\nulldelimiterspace}
}} \right)_
t} \over {K_S + t}}
$$
or it also can be represented as:
$$
{N \over {N_0 }} = {{K_S + t - \left( {{N \mathord{\left/
{\vphantom {N
\kern-\nulldelimiterspace}
}} \right)_
t} \over {K_S + t}}
$$
where
N is the effluent turbidity [-]
No is the maximum/initial effluent turbidity during settling state [-]
(N/N0)max is the maximum value that the hyperbolic function will asymptomatically approach to.
t is the time [T]
KS is the rate of settling flocs [T].
Terminal velocity is the velocity of the flocs settling in the column.
$$
v =
$$
where
v is the terminal velocity [L/T2]
L is the distance of the column above turbidimeter [L]
t can be redefined as:
Equation 2
$$
t =
$$
substitution of Equation (2) in Equation (1) yields:
Equation 3
$$
1 - {N \over {N_0 }} = {{\left( {{N \mathord{\left/
{\vphantom {N
\kern-\nulldelimiterspace}
}} \right)_
L} \over {K_S v + L}}
$$
Reciprocating both axes in Equation 3 gives:
Equation 4
$$
{1 \mathord{\left/
{\vphantom {1 {\left( {1 - {N \over
\kern-\nulldelimiterspace} {\left( {1 - {N \over
}} \right)}} = {{K_S v} \over {\left( {{N \mathord{\left/
{\vphantom {N
\kern-\nulldelimiterspace}
}} \right)_
L}} + {1 \over {\left( {{N \mathord{\left/
{\vphantom {N
\kern-\nulldelimiterspace}
}} \right)_
}}
$$
For the experimental data that is less than number of window specify (at lower end), Equation 5a is used and Equation 5b is used at the upper end.
Equation 5a
$$
{{\sum\limits_
^
} \over {2i + 1}}
$$
Equation 5b
$$
{{\sum\limits_
^
} \over {2n - 2i - 1}}
$$
For any other experimental data in between these two condition, Equation 6 is used.
Equation 6
$$
{{\sum\limits_
^
} \over w}
$$
where
w is the number of window (odd number)
Y is the data
n is the length of experimental data
m is (w-1)/2