Environmental monitoring is a key function that will add value to businesses seeking operational excellence and allow them to demonstrate due diligence to environmental agencies. In many cases, environmental monitoring is carried out by dedicated instrumentation and recording systems, but some businesses may be surprised to find that the addition of a few more data points to an existing process information management system (PIMS) may make it possible to start analyzing a plant's environmental output.

The resulting analysis can help companies achieve specific business advantage by using data from mandatory environmental record keeping and reporting with other information to improve plant operations.

To provide comprehensive environmental reporting on an enterprise scale, information must be gathered from a range of systems, including:

• Process data from PIMS;
• Laboratory data from laboratory information management systems (LIMS);
• Financial data from enterprise resource planning (ERP) systems; and
• Other systems contributing data, such as maintenance systems.

The size of a supervisory system at the reporting and analysis level is quite small in comparison to contributing systems, as it only needs to record data pertinent to the functions defined for its purpose. Information output is typically lower than the frequency of PIMS data gathering because the environmental system looks at events over longer time periods.

When flows are considered using mass balancing, as in this case where 20 + 40 ? 63, it is possible to adjust their rates and inventories to make the measured values more accurate and better fit the overall balance of the production unit or plant.

Value can be added to reporting data by mapping the plant into operational units. An informational plant model can then define cost centers and product and energy flows between them. Knowledge about the operational characteristics of plant items can also be entered into such a model-based system. With this information, an object-oriented system can be used to define and create performance ratings, production accounting, and mass balances across redefinable but specific areas of the business. This will allow operators to seek and quantify losses to the atmosphere and other waste emissions.

Mass balancing is a cornerstone for such a system¡ªsee 'Mass balance' graphic. Three tags in the graphic have specific flow rates associated with them. The graphic illustrates a situation where, due to measurement inaccuracies caused by errors or the presence of too much instrumentation, the two feeder flows do not equal the total flow. The situation is viewed as 20 + 40 ¡Ù 63, which can be analyzed using reconciled mass balancing to resolve the differences. If the situation is 63 - 40 = X, a mass balance for the third measurement can be performed by inference. When flows are considered in this way, it is possible to adjust their rates and the inventories calculated from them to make the measured values more accurate to better fit the overall balance of the production unit or plant.

Another process benefit is that malfunctioning instrumentation can be more readily identified and problems resolved at an early stage, improving efficiencies and helping operators remain within environmental emission limits.

By providing environmental monitoring functionality on the back of a system that provides wider plant functions, it is possible to corroborate and re-use already verified information, thus keeping the cost of this specific analysis down. This re-use of verified information also saves time and ensures consistency in analysis across an enterprise.

An object-oriented system can be made aware of local and specific emissions limits, as defined by law. This knowledge will improve its functionality and usefulness dramatically. Ability to provide information on the following will also provide useful tools, such as:

• Emissions over specified time periods;
• Average values presented over specified time periods;
• Peak output; and
• Any deviations and violations.

This information will allow a company to demonstrate compliance or discuss any breaches with regulatory bodies. By tying a supervisory system holding environmental data to an electronic log record, information concerning breaches of limits can be recorded alongside details of actions taken to resolve the problem, further demonstrating due diligence to environmental bodies. Electronic logs will also enable better communications between plant shifts.