Table of contents

• 1. General presentation of the DST
• 2. Step-by-step description of the main functions
• 3. Additional information
• 4. Example of analysis
• 5. DST user interface

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1. General presentation of the DST

The Decision Support tools (DST) was developed in the frame of the Interreg European project Phos4You. The project aims at improving the recycling of the Phosphorous (P) from urban wastewater treatment plant (UWWTP) by supporting the development of 6 P-recovery technologies for municipal sewage water and 5 new products from P-recycling processes for fertilizer.

The goal of the DST is to provide relevant information to stakeholders to identify the potential application of P recovery solutions at the scale of UE countries. To that end, the tool is designed to identify the treatment plants according to their characteristics and their local context. These criteria can be used to search plants suitable for the specific constraint of a given P recovery solution.

While UWWTPs and incinerators treating sewage sludge are both targets by the project, the tools focused mainly on UWWTPs due to the lack of detailed information on the incinerators.

The DST offers two approaches to the wastewater treatment data. The first and main one is based on the UWWTPs themself as an entry point. The second use areas (administrative areas, watersheds, or regular grid) to interact with databases.

1.1. Treatment plants approach

The treatment plants approach is based on two essential components:

• The selection of treatment plants
  The website provides a user-friendly tool for exploring wastewater treatment data in multiple dimensions. The underlying database contains information for both UWWTPs and incinerators. For UWWTPs, several data sources are available to combine spatial coverage and data accuracy. The parameters for filtering the data are gathered in three groups (table below): UWWTPs characteristics, the territorial context, and the UWWTPs network.

  List of criteria used in the DST to filter UWWTPs data

  UWWTPs characteristics	Main characteristics of the UWWTPs	Treatment capacity (p.e) Phosphorous removal Phosphorous removal performance
  Territorial context	Regulation and eco-environmental local or regional context of the UWWTPs and their discharge points	P recovery obligation Sensitive areas for phosphorous Ecological water quality of watersheds Livestock density (nuts 2)
  UWWTPs network	Spatial organization of the UWWTPs network based on their proximity for cluster identification or isolated plants	Number of plants located within a specific radius distance of each plants Sum of capacities of the plants located within a specific radius distance of each plant

• The data aggregation
  By default, the DST returns a simple map of the location of the plants selected. An additional aggregation step allows summarizing information at a different spatial scale and with different variables. The DST provides three groups of spatial aggregation further divided into several scale level:
  • Administrative limit: Nuts 0, 1, 2, 3
  • Watershed from Ecrins: Basins districts and sub-basins
  • Regular grid: 50km hexagonal grid

  The following figures show an example of the different aggregation scales:

  

  

  

  

  

  

  

  The aggregation process summarizes the information with 4 indicators:

  • Number of plants selected in an area
  • % of plant selected in the area (number of plants selected in regards to the total of plants in the area)
  • Sum of treatment capacity of the plant selected in an area
  • % of the capacity of treatment of the plant selected in an area (total treatment capacity of the plants selected in regards to the total of treatment capacity in the area)

Note: The two steps described above are mixed in the tool interface for better user experience.

1.2. Areas approach

The area approach aims at providing an overlook of target territories and providing a simple synthetic profile of their UWWTPs system. It provides an interactive tool for the exploration of the UWWTPs of specific areas. Several types or sizes of areas can be selected: administrative limit (Nuts 1, 2, 3), watershed from Ecrins (Basins districts and sub-basins), and regular grid (50km hexagonal grid).

The tool returns 3 types of information for a selected area:

• A map of the selected areas with the UWWTPs. The map symbols provide information about the relative difference of treatment capacity, the P removal, if P removal exists, the performance (pass or fail test), and the type of receiving areas (sensitive areas for phosphorous).
• A histogram of the UWWTPS treatment capacity. The histogram ranges are adapted for better readability.
• A synthetical bar graph of the UWWTPs. The graph gives the % of plants and the corresponding % of capacity (treatment capacity of the selected plants in regard of the total of the area) of 1) the plants with P removal, 2) if P removal exists, the performance (pass or fail test), and 3) the plants discharging in sensitive areas.

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2. Step-by-step description of the main functions

The following steps correspond to the suggested method for using the DST. The entry point can be done trough the treatment plants or trough the territory

2.1. Treatment plants approach

1. Add treatment plants data:
   Click on Treatment plants to add a treatment plant layer.
2. Open Treatment plants settings:
   On the layer click on the setting button
3. Select the type of treatment plants targeted:
   Select on the dropdown list UWWTPs or incinerators.
4. Select the source of data:
   Select the data source in the dropdown list. Differents options are only available for the UWWTPs.
5. Select the parameters and the values targeted:
   Change the values of the parameters of the UWWTPs characteristics, the territorial context and the UWWTPs network (spatial organization).
   To update the map with the new settings, click on the button Click to Update on the top of the panel (the map is not updated automatically).
6. Select the data aggregation:
   In the data aggregation section selected the aggregation for the output: none (map of the plant), administrative scale (nuts 0, 1, 2, 3), water catchment scales and a regular grid.
   The aggregation process returns the number of plants or the sum of the treatment capacity of the plants selected. Optionally, the value of the outputs can be expressed in percentage % (number of plants selected in regards to the total of plants in the area or the total treatment capacity of the plants selected in regards to the total of treatment capacity in the area).
7. Explore the map:
   A click on the map symbol provides further details on the corresponding element.
8. Explore the data through the attribute table:
   Display the attribute table of the current analysis by clicking on the attribute table button in the layer options panel.
9. Export results:
   If required, export the attribute table in .csv by clicking on the export button and the right side of the attribute table.

2.2. Areas approach

1. Add territory data:
   Click on Territory to add a treatment territory layer.
   A new layer is loaded with the NUTS 3 delineation by default.
2. Open territory settings:
   On the layer click on the setting button
3. Select the scale/size of territory:
   Several territory scale are available: none (map of the plant), administrative scale (nuts 1, 2, 3), water catchment scales and a regular grid.
   
4. Select the source of data:
   Select the data source in the dropdown list. Differents options are only available for the UWWTPs.
5. Select the target territory:
   On the map, click on the territory of interest to display the UWWTPs of the area and charts
   Note: To be able to select a territory, the territory layer setting should be open.

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3. Additional information

Information supporting the criteria for the treatment plant selection are also available as individual map layers. In addition, other relevant datasets, such as census data, were added as complementary information.

To display the additional maps, click on Additional data and select the dataset to display on the map.

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4. Example of analysis

For example, a company is developing a recovery solution that has been designed specifically to handle P recovery for small UWWTPs (<5000 p.e.) without P removal, remote (isolated), and in areas with high eutrophication pressure.

They would like to identify the UWWTPs that match their criteria to have a better perspective on their potential development.

On the DST, a new treatment plants layer is added. Then the layer settings are adjusted to match the company criteria:

List of criteria used in the DST to filter UWWTPs data

Treatment capacity	<5000 p.e.
P removal	No
Type of discharge area	Sensitive area
Ecological water quality status	More than 60% of water bodies in poor or bad ecological status Note: The water quality status is still not included for the UK area. As a consequence, if this setting is adjusted, all plants from the UK are excluded.
Cluster analysis	UWWTPs remote or isolated. The plants are selected if they have less than one neighboring plant at less than 20 km.

The map provides the location of all the plants filtered. More information is available through the attribute table that can be downloaded for further analysis.

Some small clusters of plants can be identified on the map. But, do these plants represent an important share of the relevant authority? For example, at the smallest administrative limits available in the DST, the NUTS 3, do these plants represent a significant proportion of the plants in the area.

In the layer settings, the study scale is set to Nuts 3 and the output values to the Nb. of plants in %.

The resulting map shows that the selecting plants never represent a very high percentage of the treatment solution in nuts 3 areas. However, they are significant for at least 3 locations.

Important note: those results are based on the EU database that lacks information for small UWWTPs. For a more accurate analysis, alternative databases should be used.

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4. DST user interface

Layers management

To improve map readability, the layers can be reordered by simply drag and dropping them inside the layer list.

Layers have options that are displayed when clicking on a specific layer of the layer list.

These options allow setting the layer opacity , to display attribute table , to get additional information , and finally to remove the layer .

Background layer selection

Three background maps can be selected according to user preference or to improve the final map readability:

• CartoDB Positron
• Stamen Toner Lite
• Esri World Topo

To change the base map, click on the layer button on the right side of the map. Then, select the background map in the dropdown list that appears.