statements software: Aquacalc

Water quality can be defined by numerous parameters. However, only a few qualitative measurements are installed in-line.

Regularly performed laboratory measurements remain essential for checking the quality of the raw water and of the treated water. Therefore, the operator has no real time data on his plant’s performance.

This performance will gradually be optimised by means of statements software run to check daily that treatment is within applicable limits and controlled from a financial viewpoint. SUEZ has standardised a solution that if offers for all its plants.

The purpose of the Aquacalc software is to provide water treatment plant operators with a tool that can be parametered and that allows them to:

• automatically collect and record all technical data;
• validate this data in order to guarantee its reliability;
• edit this data as regular or occasional statements and reports (in Excel).

Aquacalc functionalities

Data acquisition: this function allows the operator to work with a large number of external data sources (Supervision, Excel, text files and any ODBC compatible database: Access, Oracle…).

Long-term archiving: used to archive data that has been acquired or calculated. These figures are stored in Aquacalc-specific files or in an ODBC compatible database (Access, Oracle…). These archives can be kept for several years.

Automatic data validation: each item of data can be linked to a validation method so that each measurement taken by a sensor is validated by three criteria:

• its value: is the measurement within the acceptable range?
• its variation: is the measurement’s rate of variation within the acceptable range?
• its constancy: has the measurement remained virtually constant over a certain period of time?

A global validity index combining these three criteria will then be linked to each value. This measurement will subsequently be confirmed automatically as valid or invalid depending on whether its global validity index is above or below a threshold (specific to each value) set by the operator.

Calculation of the global confidence index can also use the measurement context. This context is defined by one, two or three all-or-nothing (TOR) sensors. Each of these TOR sensors defines measurement validity according to one criterion:

• availability: is there an ongoing test or maintenance task in hand?
• communication: is the data transfer channel operational?
• the process: is the sensor operational?

If, on a given date, one of these indicators readings is invalid, the sensor’s confidence index is reset to 0.

Data correction: on completion of the automatic data validation phase, the operator can amend data deemed invalid using a graphics plotting editor or a spreadsheet.

Creating reports: Aquacalc is a tool that allows the user to easily create and edit reports as Excel sheets. Report editing can also be scheduled to occur automatically on a set date.

Data and report access: data can be looked up as curves or tables. The web access module allows any user of a company network to easily access data and reports using a browser (Internet Explorer or Netscape Navigator).

In addition to these functionalities, the statements software is ergonomically simple and does not require advanced computerisation skills.