By order of the FSBI State Scientific Research Institute of Industrial Ecology employees (FSBI GOSNIIENP) The St. Petersburg Federal Research Center of the Russian Academy of Sciences (SPC RAS) has developed and successfully tested a method for the rapid detection of illegal discharge of waste from enterprises into sewers and reservoirs based on passive radio frequency identification technology using encapsulated RFID tags. Some of the results of the project have been published in the leading scientific journal Izvestiya Kabardino-Balkaria Scientific Center of the Russian Academy of Sciences.
Protecting water bodies from industrial pollution is a critically important task, as today they are the main sources of drinking water for millions of people, animals and plants. Their pollution can lead to serious public health problems, as well as the death of flora and fauna, and the destruction of entire ecosystems. Clean water bodies are the most important factor for the successful operation of agriculture, fishing, tourism, and for a comfortable life for indigenous peoples living nearby. Protection of water resources from ingress of toxic substances is regulated by a variety of legislative acts.
However, there are cases when industrial enterprises illegally connect their wastewater to storm sewers that do not have complex sewage treatment plants. Wastewater often contains toxic chemicals, heavy metals, oils, and other pollutants that eventually enter reservoirs through storm drains. One way to solve this problem is to regularly inspect industrial plants and monitor storm sewers to identify illegal connections to them and prevent contamination.However, most monitoring methods (visual inspection, smoke tests, dye use, flow tracking, and chemical analysis of waters) are either expensive or not versatile enough to detect any type of contamination. “We have investigated the possibility of using passive radio frequency identification technology of the EPC Class 1 Gen2 standard for the rapid detection of unauthorized connections and wastewater discharges from industrial enterprises into storm sewers. It is based on the use of cheap sensors with a built-in RFID tag, the movement of which through sewer pipes can be monitored automatically.” – says Vladimir Dashevsky, Senior Researcher at the St. Petersburg Institute of Physics and Technology of the Russian Academy of Sciences. A key element of the sensor created by specialists of St. Petersburg FIT RAS is a passive RFID tag. It is an assembly chip with a small printed antenna that stores information about an object and allows it to be read using a special RFID reader from a distance of several meters. Passive RFID tags are characterized by lightness, compactness and cheapness. However, in sewage conditions, reading RFID tags is significantly hampered by the absorption of the radio signal by the earth's thickness, as well as the shielding effect of water. Therefore, the main research was aimed at finding the optimal sensor design and ways to reliably read them in storm sewer pipes. The essence of the method lies in the fact that during control measures, sensors are discharged into the drain wells of industrial facilities. In this case, the EPC code is recorded in the RFID tag, characterizing the location and time of the reset of each sensor. If there is an illegal connection of an industrial drain to a storm sewer, the sensor eventually ends up in the control well of the storm sewer, where its EPC code is read using a reader lowered into the well and transmitted to the data processing server. The proposed approach makes it possible to simultaneously diagnose several drains of the same sewer system, which distinguishes it from the traditional method involving the addition of dyes or isotopes to water. The time and place of the reset, recorded in the memory of each sensor, allows you to identify it and unambiguously determine the path of its migration, even if it takes a considerable time. In order to assess how successfully the sensors overcome pipes of various bends, diameters and fillings, several stands were assembled simulating sections of storm sewers. In general, this work demonstrated the promise of the proposed method. Based on the information collected at the stands, the design of the sensor housing has been improved. Then the researchers conducted a full–scale experiment on a direct section of a real storm sewer located at the site of the industrial partner of St. Petersburg FIT RAS, ECOPROM LLC, responsible for the operation of sewer networks in the Obukhovo industrial zone in St. Petersburg. “Experiments have shown that RFID technology works reliably underground: all the sensors that sailed into the control well were repeatedly and reliably read by the reader. However, the time they travel through pipes through shoals and blockages can be long and difficult to predict. To increase the speed and convenience of deploying the monitoring system, we have equipped an operator's seat in a minibus. Nevertheless, in the general case, such an exit post is clearly insufficient.” – notes Vladimir Dashevsky.
Therefore, further development of the technology involves the creation of stationary automated complexes that would monitor sensors at the outlets of storm sewers into reservoirs. Automated monitoring of storm sewers will make it possible to quickly detect the presence of overflow of domestic and industrial sewers into storm sewers and fine violators who drain their emissions bypassing sewage treatment plants.