BVT-Merkblatt zu Abwasser- und Abgasbehandlung

Annexes
Its concept is to define and find water saving potential by, e.g. piping and control changes, and
to minimise waste water discharge by process modifications, thus enabling selective waste water
regeneration and reducing treatment costs. It is also used to design or re-design distributed
effluent treatment so as to lower capital costs by reducing the hydraulic load of a central
WWTP.
Its application can be broken down into four steps [cww/tm/86]:
Step 1:
Drawing a flowsheet of the entire water system (supply, discharge) that shows all places where
water is used, and all points where waste water is generated.
Developing a water balance accurate to within 10 % of the amounts of the larger streams.
Defining the appropriate data for the analysis by determining water sources and water sinks.
A profile is presented in Abbildung 7.3 [cww/tm/86].
Abbildung 7.3: Pinch Technology – Analysis, Source and Sink Curves
Step 2:
� Selecting key contaminants or properties that prevent the direct re-use of the respective
waste water stream
� Choosing design concentrations – maximum allowable for sinks, and minimum practical for
sources.
Step 3:
� Developing the multi-dimensional pinch analysis to determine optimum matches between
sources and sinks. Appropriate software is available for this. The procedure includes identification
of pinches and a consideration of process modifications and regeneration options
resulting in lower targets.
Step 4:
� Repetition of step 3 until a practical design has evolved.
Waste Water and Waste Gas Treatment 325