Organic Waste Recycling

430 Organic waste reuse and recycling: technology and management

For fecal coliform removal
Assuming that during wastewater application, the height of wastewater is 5 cm
throughout the entire down slope distance

Wetted area

Hydraulic radius, R =

Wetted perimeter

Q 100 m^3 /day

Width of the applied area = = = 41.7 m

q 0.1 m^3 /hr-m

≈ 42 m

42 (0.05)

R = = 0.05

42+2(0.05)

1

v = (0.05)2/3 (0.02)1/2 = 0.05 m/sec

0.38

100

Fecal coliform reduction = exp (-0.2 t)

6x10^5

t = 43.5 min

Slope length for fecal coliform removal = 0.05x43.5x60

= 130.5 m

Choose slope length of the OF area of 130.5 m to provide the treated effluent
quality meeting the required BOD 5 and fecal coliform concentrations. Width of
the applied area is 42 m.

8.6 System monitoring

Monitoring of land treatment systems involves the observation of significant
changes resulting from the application of wastewater. The monitoring data are
used to confirm environmental assessment and to determine if any corrective
action is necessary to protect the environment or maintain the renovation
capacity of the system. The components of the environment that need to be
observed include wastewater, groundwater, and soils upon which wastewater is
applied and, in some cases, vegetation growing in soils that are receiving
wastewater.