DEVELOPMENT OF SOFT SENSORS TO OPTIMIZE OPERATION AT SMALL, UNMANNED WASTEWATER PLANTS
24 August 2022
In cooperation with VCS Denmark
Advances in mechanistic and data-driven modeling techniques have so far benefited resource-rich wastewater facilities due to their abundance of hardware, data, and know-how. Soft sensors, which rely on mathematical models (rather than hardware) to estimate wastewater parameters, have the potential to provide an economical alternative for facilities with fewer resources to acquire and maintain hardware, and even serve as proxies for parameters for which online sensors have not yet been developed. The project aims to develop a soft sensor for “phosphate” concentrations and consequently chemical dosing requirements, based on available process data (inlet flow, etc..) and a soft sensor for “sludge age” based on available process data.
Denmark has more than 700 treatment plants over 30 PE (1 PE is equivalent to the amount of sewage one person produces per day), which treat a total of 7.3 million person equivalents wastewater each year. Although the largest 30 plants account for 53% of the treatment, hundreds of small treatment plants are operated and maintained to protect the aquatic environment into which they discharge the wastewater. These small treatment plants generally lack resources compared to the larger treatment plants and typically lack personnel and advanced control. The hardware traditionally needed to optimize operations such as advanced online sensors are expensive, including in operation. Highly qualified personnel to operate these facilities are not only expensive but often also a geographically scarce commodity. Some small treatment plants are operated as satellite plants by larger treatment plants, in such cases, the staff can run several small treatment plants centrally. With an increased focus on all strains on our scarce nature and environment, it is also necessary to optimize the operation of the smaller and very small plants. In part, there are obvious environmental effects as many of the small plants emit to extremely sensitive recipients and partly there is the economic and efficiency aspect, where the operation of the small plants in many situations has a relatively high price if it is assessed per processed m3. For many years, the Danish environmental industry has made a mark on the large treatment plants internationally, as to why it will support our industry to also show the way for the smaller and very small facilities, not least in light of the increasing discussion about central treatment facilities rather than decentralized ones. A project like this will support our position internationally and be able to directly support the export of Danish water technologies.
The project will also show a new way of thinking concerning what demands and wishes are reasonably possible for even small installations where monitoring until now has typically been in the form of alarms when something is wrong. With this initiative, the optimization possibilities that we know from the large plants can be directly transferred to even very modest plants via central monitoring and optimization but with decentralized process plants.
The industry has a challenge concerning increased sustainability in both operations and e-tabulation of facilities. This project will increase the possibility of using existing infrastructure more efficiently and thus minimize resource consumption.
The project is aimed at an efficient innovation process where VCS Denmark Syd works as a supply together with an agile and innovative software developer who brings extensive and versatile IT knowledge to the project and we will combine this knowledge with deep process understanding from VCS Denmark.
There is no satisfactory phosphate sensor on the market today, nor a sensor that can determine the age of the sludge to maintain the optimal amount of sludge in the plant. It will be one cost-effective solution to develop a soft sensor that is cheap to operate, which will increase the number of
measurements, which in turn provide a significantly improved control and analysis basis. The goal is to apply existing equipment and mechanistic models for the new sensors, increasing efficient collection as well as equipment utilization. Concerning the phosphate sensor, the project will be able to minimize chemical consumption and ensure optimal dosage. It will be a natural part of the necessary digitization of the water sector
and be targeted at facilities that typically do not have the same vigilance as the large facilities, although the number is much larger of these small plants.