TABLE OF CONTENTS This chapter presents calculations on stream sanitation. The main portion covers the evaluation of water assimilative capacities of rivers or streams. The procedures include classical conceptual approaches and pragmatic approaches: the conceptual approaches use simulation models, whereas Butts and his coworkers (1973, 1974, 1981) of the Illinois State Water Survey use a pragmatic approach. Observed dissolved oxygen (DO) and biochemical oxygen deman (BOD) levels are measured at several sampling points along a stream reach. Both approaches are useful for developing or approving the design of wastewater treatment facilities that discharge into a stream.
In addition, biological factors such as algae, indicator bacteria, diversity didex, macroinvertebrate biotic index, and fish habitat analysis are also presented.
Point source pollutants are commonly regulated by a deterministic model for an assumed design condition having a specific probability of occurrence. A simplistic dilution and/or balance equation can be written as
| where C d | = completely mixed constituent concentration downstream of the effluent, mg/L |
| Q u | = stream flow upstream of the effluent, cubic feet per second, cfs |
| C u | = constituent concentration of upstream flow, mg/L |
| Q e | = flow of the effluent, cfs |
| C e | = constituent concentration of the effluent, mg/L |
Under the worst case, a 7-day, 10-year low flow is generally used for stream flow condition, for design purposes.
A power plant pumps 27 cfs from a stream, with a flow of 186 cfs. The discharge of the plant's ash-pond is 26 cfs. The boron concentrations...
