Instrumentation, control and automation progress in the United States in the last 24 years

Abstract

A historical overview is presented of instrumentation control and automation as applied in US wastewater treatment plants. A description is given how computer equipment has progressed through direct digital control, distributed control, programmable logic controllers, to the use of personal computers along with PLC's or I/O boards in minimum systems. Software developments have brought systems analysis, expert systems, fuzzy logic control, and artificial neural network control. An instrumentation test house has been organized in the US to improve the odds of purchasing reliable instruments. Technical Conferences on ICA are presented regularly by the American Water Works Association and the Water Environment Association. There is still need for designers to consider a complete system that includes a data base for automatic preparation of reports on the plant for use at other levels as was called for by delegates to the early workshops.

Regards croisés sur l'état de la Loire Moyenne : potamoplancton et qualité de l'eau, quel enseignement tirer de 20 années d'études ?

“…Les séries temporelles de données sont peu nombreuses dans la littéra-ture et, selon les auteurs, le long terme recouvre des périodes de temps très variables : 10 ans pour le Golfe de Tigullio et illustrant des changements climatiques (Licandro & Ibanez, 2000) ; 13 ans pour l'Elbe et montrant une amélioration de la qualité de l'eau (Lehmann & Rode, 2001) ; 20 ans pour la baie de Seine avec un suivi des flagellés, de l'azote et du silicium (Guillaud & Menesguen, 1998) ou pour la Neuse et soulignant les difficultés à mesurer dans cet intervalle de temps les améliorations apportées par les traitements amont (Stow et al, 2001) ; 24 ans pour faire le point sur les procédés de mesure et d'instrumentation (Garrett, 1999) ; 90 ans en Seine et en Marne, en relation avec le développement socio-écono-mique, et les déficits brutaux en oxygène ; 100 ans pour des cours d'eau danois, illustrant la perte de richesse de la végétation en liaison avec la modification des habitats (Riis & Sand-Jensen, 2001). Certains auteurs font également le point après de longues périodes, comme ce fut le cas pour les diatomées de Grand River (Rott, 1995).…”

Sewage Treatment Plants

“…During the last 20-25 years most wastewater treatment plants have been replacing the old control and monitoring systems with new SCADA systems (Supervisory Control and Data Acquisition), which allow both the central monitoring of a plant and its controllers and the storage of plant data (Garrett, 1998;Olsson et al 1998;Lynggaard-Jensen, 1999). However, independently of the introduction of SCADA systems, the control of plants remained mainly focused on strategies based on actuation times (with a few exceptions such as control based on on-line measurements of hydraulic flow-rates and dissolved oxygen concentrations).…”

Data Management Solutions for Wastewater Treatement Plants

“…As discussed by Garrett (1998), technology has brought about innovative and elegant solutions to control and monitoring, but has seemingly lacked in storing and presenting the acquired data in an efficient manner. The Cimplicity system allows real-time monitoring and control at the NEORSD's facilities.…”