Water Journal : Water Journal August 2012
source management refereed paper technical features 80 AUGUST 2012 water under the network schematic. From this screen the trade waste officer can: • Change details of individual pump stations; • Access a network pump station's flow summary that compares the modelled flows to the design average daily flow and the design duty flow. The output can be filtered to show flows that exceed the design average daily flow; • Access pump station flow details. STP capacity mass balance page (Figure 3) The model provides a schematic of the significant processes in overview form, with streams in and out of the STP shown. Trade waste officers can select and view six contaminant or flow parameters at a time (from an extensive list of parameters of interest), all with relevant units applied. The trade waste officer can select a year from 2011 to 2050, and the model will make projections of flow and mass load based on catchment growth projections contained within a relevant planning report (in this case, the 2006 Oxley Creek Upgrade Report). The flow condition can be chosen (from a dropdown menu) and this will update mass balance flows and loads based on the selection. The four flow conditions are based on typical ratio assumptions defined below: • ADWF (average dry weather flow); • PDF (peak daily flow condition) 2.2 x ADWF; • PWWF (a sustained 24-hour flow condition) 1.6 x ADWF; • Peak Hourly Flow (sustained 1-hour flow condition) 4 x ADWF. Care must be taken to ensure that the selection of flow condition is relevant to the particular area of the model being observed (i.e. peak flow conditions are relevant for observing constraints at inlet works or pump stations, but not the effect on contaminant levels in treatment processes and sludge handling). A detailed view of input and output streams for any particular segment within the STP can be viewed (by clicking on the relevant segment). The detail provides capacity analysis that compares the design/typical values to those predicted in the model. If a capacity limitation has been breached, the relevant cell will be highlighted in red. All assumptions made within the STP capacity mass balance can be changed from this page (by clicking on the "Mass Balance Assumptions" button). Output summary reports The following output summary reports are able to be generated: • Network and STP Capacity Highlighted Issues This report shows capacity issues that have been breached (only), and can be used to highlight significant issues before and after a new trade waste connection is added to the model (Figure 4). • Network and STP Capacity Triggers Summary This report shows all of the capacity triggers that are tested in the model, and can also be used to highlight changes before and after a new trade waste connection has been made. • Individual Constituent Summary This report shows the sources for a particular contaminant in tabular and graphical form. A complete mass balance through the STP is also shown in tabular and graphical form. • Brief Summary of All Constituents This report shows the sources of each constituent (municipal, commercial or imported sludge), and the fate of the contaminants. This form is intended to be used as a calibration tool for the database model (i.e. to fine-tune inputs into the database model). • Individual Trade Waste Connection Summary This report shows the details of any individual Cat D trade waste connection, and the summary of the individual trade waste connection flows and contaminants used in the database model compared to: -- The sample average, maximum, minimum or latest sample; -- The trade waste approval conditions. This form is also intended to be used as a calibration tool for the database model (i.e. to fine-tune inputs into the database model). Maintenance QUU recognises that the maintenance of the mass load model is as important as its development. Although the data input duties are not onerous, regular input data updates are necessary -- requiring the Figure 2. Pumping station network screen. Figure 3. STP capacity mass balance screen (hypothetical data).
Water Journal September 2012-1
Water Journal July 2012