Environmental Engineering Reference
In-Depth Information
FIGURE 20.6
Single-home graywater system.
Collection main
Fats, Greases, & Oils
Interceptor tank
Service
lateral
Inflective
gradient
Soluble BOD
Building
sewer
Settleable solids
Euent
FIGURE 20.7
Settled-sewage collection system. Reprinted from EPA (1991).
CLUSTER TREATMENT SYSTEMS
While subsurface-flow constructed wetlands are suitable for smaller cluster
systems, other forms of ecological wastewater management become more cost-
effective as systems grow larger. These include surface-flow wetlands and pond
systems, as discussed in chapter 18. A typical surface-flow wetland is shown in
Figure 20.9.
Because these passive ecological systems are land intensive (see Table 18.1),
semipassive systems (wetlands or ponds that rely on some degree of mechanical
assistance) are often used. The advantage of semipassive systems is that they occupy
less land area, retain some of the resiliency of passive ecological systems (not all
Search WWH ::
Custom Search