386 Organic waste reuse and recycling: technology and management
Figure 8.1 Soil type vs liquid loading rates for different load application approaches
(U.S. EPA 1976)
The objectives of SR process are: treatment of the applied wastewater;
conservation of water through irrigating landscaped areas; and economic gain
from the use of wastewater and nutrients to produce marketable crops.
The principal limitations to the practice of SR are: the considerable land area
required, its relatively high operating cost, and the treatment site is usually long
distance away from the wastewater sources. As shown in Figure 8.1 and Table
8.1, wastewater application rates for SR are smaller than the other two land
treatment processes. The SR application rates vary from 2.5-10 cm/week
depending on the types of crops and soil. In some cases, certain wastewater
characteristics, such as high salt and boron concentrations, may preclude
irrigation of many crops, especially in the arid regions.
AVERAGE LIQUID LOADING RATE, IN/WKInch = 2.54cmIRRIGATIONOVERLAND
FLOWINFILTRATION
PERCOLATION