Due to increasingly strict environmental regulations, the cost of handling
various waste streams is gradually rising. Therefore, it is crucial to
minimize unnecessary stream merging when designing distributed wastewater
treatment systems, to reduce the overall treatment flow rate whenever
possible. In a distributed wastewater treatment system, the wastewater
streams are separated for treatment and only combined when necessary. This
results in a significant reduction in the total treatment flow rate compared
to traditional centralized treatment systems where all the streams are
merged before treatment. Design of a distributed wastewater treatment system
can be accomplished using pinch analysis and mathematical programming
approaches. This paper suggests a straightforward approach for designing
such networks, with the following steps in the design process: First, the
primary function of each treatment unit is determined. Next, using the pinch
method, the lowest treatment quantity is determined for the primary
pollutant for each unit. Finally, a three-unit group is selected, with the
pinch stream partially treated, the streams above the pinch completely
treated, and the stream below the pinch completely bypassed. Two literature
case studies demonstrate the viability and effectiveness of this strategy.