as they arise. Better information is available to more quickly troubleshoot issues, and action can be immediately taken through the control system instead of travelling to the affected location. Improved responsiveness can also result in reduced travel time and labor. It is important to point out that, for many utilities, operators are required to travel to the location of an alarm to investigate the problem. However, proper automation can help identify problems, improve data collection, and increase the ability to “fail” in a predictable manner, thereby improving the overall response to upsets or alarm conditions.
FIGURE 2.1 Performance comparison for a WRRF with manual and automatic SRT process control (Tchobanoglous, 2003).
2.2.4 Enhanced Decision Making
Improved measurement and data collection can lead to better information being available for planning, management, and operational decisions; engineering studies; and maintenance and troubleshooting. For example, if appropriate power monitoring is put in place at a WRRF, then data can be collected and used to evaluate the actual energy consumption of particular pieces of equipment or unit processes. Energy consumption data combined with operational data such as pressure and flow can be used to evaluate equipment efficiency and performance for a wide range of operating conditions. If the data indicate that the equipment is not operating at peak efficiency, this can help identify what the issues could be. For example, it could point to a degradation of equipment performance over time or that the equipment is being operated under condition changes that are less than optimal for the particular equipment. In many instances, minor operational or automation changes can improve energy efficiency or energy costs. Power monitoring should be evaluated so that metering, or submetering, is installed at the correct locations required to understand where energy is being consumed in the facility.
2.2.5 Reduced Risk
Today, penalties for improper risk management include fines; incarceration; wasted resources; and public outrage at facility odors, unsightly receiving waters, and discharged toxics. Instrumentation and controls can reduce the risk of permit violations, which are very costly. By automating repetitive tasks, potential entry errors can be reduced, thereby reducing the potential for accidents (e.g., chemical spills, fires, electric hazards, human fatalities, etc.). Control systems and associated security improvements can improve a utility’s ability to identify security issues and to respond faster.
2.2.6 Workforce Morale and Aging
Automation allows operators to focus on optimizing a facility as opposed to “being” the control system. In addition, institutional knowledge can be incorporated to operating control strategies, reducing labor requirements, and preparing a utility for the loss of long-term knowledgeable staff.
2.2.7 Customer Satisfaction
Automation can help identify potential system upsets earlier, thereby helping to avoid issues and improving overall operational efficiencies of a utility. These issues, in turn, can affect overall end-user satisfaction.
3.0 AUTOMATION COSTS
Automation equipment, including sensing instrumentation, control elements, controllers, software, and programming, typically adds at least 4 to 12% to the total cost of building a treatment facility. Project costs are site-specific and depend on the treatment processes involved and managers’ decisions about the tradeoffs between automation and labor. Once installed, an automation system has ongoing maintenance costs. Such costs should be considered early in the design phase because an automation system that is not maintained properly will eventually fail and fall into disuse.
It is worthwhile to note that many of the benefits identified in the previous section may only be achieved through the application of complex automation solutions with the associated costs. For example, tighter process control may require additional instrumentation, field devices, sophisticated software algorithms, and ongoing operations and maintenance support.
There have been studies that look at correlating the cost of SCADA systems to facility-production capacity (U.S. EPA, 1999). Although the data in these studies indicated a rough correlation, the wide deviation makes it difficult to develop a reasonable cost estimate without completing a detailed analysis.
The American Association of Cost Engineers (Christensen et al., 2011) has established five categories of estimates. Each category includes an expected level of detail and establishes goals for the probable accuracy of the estimates at each level. Many municipalities have their own established guidelines and expectations for the cost-estimate level of accuracy and these are typically tied to the phase of development of the project. The following sections provide several categories of costs to consider when developing an automation cost estimate.
3.1 Planning and Engineering
Planning and engineering services include labor and expenses for both utility and consultants in the planning, preparation, and production of design-plan specifications for construction of the project and the development of control strategies for programming efforts.
3.2 Equipment Procurement
Equipment procurement covers costs associated with the purchase of hardware and software including programmable logic controllers (PLCs), instrumentation, SCADA computers, software, and electrical support equipment (conduit and wiring, etc.). Estimations of control system hardware and software pricing should include vendor quotes, contractor overhead, profits, and bonding and insurance. The level of detail required for accurate quotes includes unit quantities, input/output point counts, operator interface requirements, and construction sequencing or schedule constraints.
Application programming includes programming of PLCs or remote terminal units and development of process graphic displays, reports, and network configuration. Depending on the level of complexity of process control strategies, the actual costs incurred from this work can be highly variable. Application programming also represents the most difficult area of work to estimate correctly.
3.3 Installation, Commissioning, Testing, and Training
This category includes costs associated with installation of automation equipment, construction administration, PLC and human–machine interface software development, system testing, and operator and maintenance training. Installation costs primarily include labor and materials, with labor representing the most significant element, particularly for control system projects.
Commissioning involves preparing the systems for operation including factory acceptance testing, site acceptance testing, instrument and device calibration, loop testing, system checkout, and startup. Training is dependent on the level of familiarity of the owner’s operations and maintenance staff, and the type of training typically depends on the complexity of the project and may be done formally or informally.
3.4 Post Acceptance Support and Maintenance
Post acceptance support and maintenance includes ongoing preventative and corrective maintenance costs, instrument technicians, calibration and maintenance, software maintenance contracts, periodic hardware and software upgrades, training, and so on.
3.5 Intangible Costs
Intangible costs include operational and technology risk, operational changes, staff
