SCADA Control and Monitoring Of Groundwater Remediation Facilities: Past, Present and Planning For the Future

Transcription

1 SCADA Control and Monitoring Of Groundwater Remediation Facilities: Past, Present and Planning For the Future Obadiah Kilonzo 1 *, Kevin Fleming 1 1 Carolina Automation Systems, 313 F US Hwy 70 East, Garner, North Carolina, USA, (*correspondence: okilonzo@casystems.com) KEYWORDS Remediation, Upgrades, Groundwater, Automation, Systems, Process, Treatment, SCADA, PLC ABSTRACT Groundwater remediation is the process of extracting water from the ground for the purpose of treatment and thereafter using it or discharging it back to the ground. This is achieved by primarily three functions: Extraction, Treatment and Discharge (ETD). Most of extraction involves pumping the water out of the ground; treatment is done by systems that are biological, physical, chemical, and/or natural. Discharge may be to a sewer, stream or to a plant for further reuse. Automation of ETD operations has been progressing as technology advances at the same time where necessary, modifying past technologies. This paper discusses this progression from the past, to the present and into the future. For example, in the past the alarms would be connected to physical indicators such as a loud horn going off and light indicators showing the area of alarm. Currently, these systems can be integrated with modern communications devices such that alarms can further be sent to a phone, and/or web and with the capability of acknowledging alarms remotely based on priority. Future alarm and event monitoring trends will continue to adopt advanced technology and may lead to having maintenance based alarms or alerts relating to plant diagnostics, controller system updates and patches. This progression advances not only the operation of the plant but also its maintenance and performance thus reducing downtime and improving efficiency. Introduction In groundwater remediation, water below the ground surface is extracted for the purpose of treatment and thereafter using it or discharging it back into the ground. This remediation is necessary because groundwater can become contaminated for human use when in proximity to areas such as landfills, industrial sites (contamination from spills), farming lands where pesticides and fertilizers are used, domestic sources and many others. Due to these multiple possibilities of sources of contamination, groundwater remediation is a unique process that provides treatment in various ways- biological, physical, chemical and/or natural. This water can further be used or discharged back to the ground. Groundwater Remediation Facilities (GRF) are the sites that perform

2 Kilonzo and Fleming 2 remediation and though the volume of water that is aboveground onsite is smaller compared to other process system facilities such as wastewater plants, GRF cover a wider area including distant wells. The methods to achieve ETD functions vary and can employ various automation aspects. For a GRF with fully integrated systems, links between the extraction, treatment and the discharge operations have to be addressed. Automation provides a viable link between these operations such that, for example, extraction can be controlled by the rate of treatment and vice versa and this can be achieved using a Supervisory Control and Data Acquisition (SCADA) system. SCADA in a Ground Remediation Facility The SCADA system mainly involves control of field devices and instruments, wiring, PLC with input/output modules and programs, HMIs, electrical control panels, data acquisition systems and servers and networks. Figure 1 Air Stripping Groundwater Remediation System As shown above, groundwater is extracted from the wells using well pumps controlled by the SCADA system in the control Room. Control and monitoring of the remote well pumps is achievable using a wireless radio system. This remediation system has 3 pumps and 2 blowers for treatment. The groundwater after treatment is discharged to a creek that runs nearby. SCADA Past, Present and Future The table below shows a comparison of the past, present and the future regarding different aspects of the SCADA system.

3 Kilonzo and Fleming 3 Comparison of Past, Present and Future on Various Items ITEM PAST PRESENT FUTURE Communication between field devices and the PLC Panel Cabinets Data Acquisition Automation Program Design Changes HMI Software and PLC Wired Wired/Wireless Wired/Wireless with a higher % leaning to wireless Slower communication- from instruments to PLC, then from PLC to HMI Much use of Panel cabinets Fully wired control cabinets- wiring to I/O modules from PLC Large panel sizes with screw-in large footprint devices Data recording from instrumentation Strip chart data collection-analog Downtime making changes when program One development software brand per PLC brand More communication- such as from instruments to both PLC and HMI Reduced use of Panel cabinets Partially wired control cabinets- wiring to I/O modules reduced with use of networking systems Medium panel sizes with DIN- rail mountable small footprint devices Data from instrumentation to PLC through a wired/ radio system Numerical/ digital Data collection Some have the ability to make program changes onthe-fly without downtime One software can work with a few different brands of PLC (has some 3 rd party drivers) PLC Design Use of PLCs only Use of PLC and pilot designs of PLC/PC hybrids Input/ Output (I/O) PLC Modules Standard IO Modulesonly inputs, only outputs Split I/O- Inputs and Outputs shared on the same module, rise of machine mount I/O Higher levels of communication- such as from instruments to both PLC and HMI wireless Much reduced use of Panel cabinets Trend towards less direct wiring of I/O points and more toward wireless network transmission Smaller panel sizes with DIN- rail mountable smaller footprint devices Data from instrumentation to PLC through wireless system Numerical/ digital Data collection to the web Full ability to make program changes on-thefly without downtime One software can work with multiple brands of PLC and/or Multiple development software with multiple PLC brands or all common brands More use of PLC/PC hybrids to the extent that PLCs are replaced with servers on the network More use of split I/O with less footprint and more of machine mount I/O with wireless web capability

4 Kilonzo and Fleming 4 ITEM PAST PRESENT FUTURE Control Capability Control of plant sections/units Data Processing Data processing offsitedata has to be transferred to another system with different software for processing Control of entire plant Data processing onsite at higher level controller (send data from remote collection to a central location for processing), also Smart processing that performs at local machine level. Data Storage Local on PC/Server Storage on central PC or server with pilot designs for Cloud-storage HMI Design Graphic P&ID view with analog numbers, use of red/green for off/on conditions HMI Functionality For monitoring a machine/ process Databases Duplication of Databases- one for HMI and one for PLC SCADA Location Alarm systems SCADA is local- local PC and SCADA software which is customunfriendly physical indicators such as a loud horns go off and light indicators showing the area of alarm Section-views with analog numbers, use of gray/green for off/on conditions For controlling, monitoring a machine/process with some tendency to program development, software on PC, remote/mobile access, compatibility with diverse equipment and softwarecan be used with Microsoft office products Duplication of Databasesone for HMI and one for PLC with pilot designs for centralization SCADA is local, pilot designs for SCADA on the Cloud, SCADA software which is custom-friendly HMI alarms integrated with communication aspects such as phone calls and s alerts. Control of multiple plants Data processing onsiteadvanced smart processing at Machine level More inclination to Cloud storage 3-D views and Icons with more advanced color options to indicate off/on conditions For controlling, monitoring a machine/process with much tendency to program development and incorporating full PLC functionality. Compatible with many software including Microsoft Office products. Centralization of Database and possibly web-based More use of Cloud based SCADA systems and custom-friendly Advanced HMI alarms not only for system operation but plant diagnostics, controller system updates and patches

5 Kilonzo and Fleming 5 Upgrades to Ground Remediation Facilities The present designs create also the possibility of system retrofits and upgrades that can embrace more advanced processes and equipment. Facilities that would rather consider upgrading only field devices and not the SCADA system may reconsider for benefits such as: Advanced Control features such as use of recipes and operation scheduling. A recipe is a collection of parameters/setpoints for a certain operation and when the operation is called upon the parameters are made readily available for the system. Various recipes can be stored in the system. A recipe for example with the setpoints for turning the treatment pumps on and off can be developed and set to be triggered by events such as season of high rainfall or floods (in this case a device such as a rain gauge will be required). Scheduling is also available where for example in an air stripping system (with a 2 blowers and 3 pumps), a schedule may be set up with various configurations such as for one week, pump 1 and blower 1, then next week pump 2 and blower 2, etc. This can be set up to run automatically with no intervention from the operator. Advanced Monitoring and Data Processing- Current systems are providing better plant operation metrics through trends and data analyzing. This becomes crucial in providing information to operation managers. Field devices can also be monitored by video. Data consolidation from multiple vendor systems is possible for GRFs that are expanding and would like to acquire (or merge with) others that have a different brand of SCADA system. Increased compatibility of SCADA with other tools such as Microsoft products, communication and advanced alarming devices. Also hardware and software is currently designed addressing compatibility. Ability to expand I/O modules rack (this is beneficial when adding more devices to the systemsuch as adding new wells). More PLC brands also are been designed with the ability for program changes (such as auto-configuring new I/O modules) with less downtime. PLC communication using Ethernet can be used to add more applications such as remote and mobile access. This creates an added feature like remote diagnostics which can reduce plant costs. For example being out the remote well and having a need to refresh/restart the central controller for purposes such as establishing communication with the well controller, with internet access, one can remote access the central controller and refresh without having any other operator assistance or having to travel to the control room. Reduced footprints of newer systems - since a new SCADA system will have less space, the possibility of having 2 systems has been attainable. This is where a new system can be set up to take over ETD operations, but the old system is left in place as a backup in case anything has to be done to the new system. The smaller footprint is not only due to the smaller physical size of the PLC but also the increased capability of handling more I/O devices. Energy Conservation- SCADA systems can be designed with more focus on energy conservation which translates to less costs.

6 Kilonzo and Fleming 6 Enhanced Alarm Management- Alarms can be set into priorities/hierarchy whereby the most critical ones get faster attention and/or activate an auto dial to call the operator. Ability to meet new opportunities- not just pumping water back to the ground but meeting new opportunities such as Heat exchange cooling for other processes and energy harvesting Going to the Future Present day challenges are providing the thrust into the future. Some of the challenges include Ethernet cabling issues and dealing with multiple switch ports, driving wireless devices with low-life battery power, wireless network isolation from other networks, advancing security for Cloud usage. As more solutions become available for the current challenges GRFs that would want to increase their automation capability will have to increase their exposure to things like: Advanced Multi drop Ethernet reducing cabling issues. Enterprise-based SCADA functionality-whereby Data can be processed and is readily available and curtailed for all decision making levels. In case of multiple plants, management level is able to see the global picture (operations of all plants). Use of cloud technology for not only data storage and remote access but real time (cloud time) control-cloud based access to a controller. Multifunctional SCADA Hardware Advanced energy harvesting methods whereby the energy necessary for operating the wireless devices is derived from the remediation process itself. Real time SCADA on Cloud without Internet limitations whereby real time data transfer and control is possible on the Cloud. This will also lead to cloud based access to the PLC which will be necessary for firmware updates etc., and with no downtime. Summary With the advancement of technology the future holds out modern devices and advanced SCADA for Groundwater Remediation Facilities. These advances make the mission of the remediation process more attainable where the process not only progresses in having a shorter ETD cycle, more water-volume handling but also minimal downtime- all this with lesser control space and providing enterprise-based control and monitoring. List of Acronyms: ETD... Extraction, Treatment and Discharge (functions in remediation) GRF... Groundwater Remediation Facilities SCADA... Supervisory Control and Data Acquisition HMI... Human Machine Interface PLC... Programmable Logic Controller I/O... Input and/or Output

7 Kilonzo and Fleming 7 Obadiah Kilonzo, PhD is an Automation Engineer at Carolina Automation Systems where he is involved with design, instrumentation and commissioning of new systems as well as upgrades. Obadiah received his Doctorate in Mechanical Engineering from North Carolina State University. Kevin Fleming is the founder and President of Carolina Automation Systems with over 25 years of experience in Control, Automation and Instrumentation. Kevin has worked with a wide variety of clients such as Water and Wastewater facilities, Pharmaceutical, Food Industry, Energy among others providing clients with practical, cost-effective state-of-the-art solutions.