WO2016049401A1

WO2016049401A1 - Telemetry for wastewater treatment systems and the like

Info

Publication number: WO2016049401A1
Application number: PCT/US2015/052112
Authority: WO
Inventors: Marc D. Kessman; Thomas E. Frankel; Seoungil Kang; Todd D. Ritter
Original assignee: Kessman Marc D; Frankel Thomas E; Seoungil Kang; Ritter Todd D
Priority date: 2014-09-25
Filing date: 2015-09-25
Publication date: 2016-03-31

Abstract

A system comprises a tank, a pipe, a pipe fitting, a sensor, an antenna, and a data processor. The pipe is disposed in the tank and is operative to transport a gas. The pipe fitting is fixated to the pipe. The sensor is located in the pipe and is operative to transmit data via radio. The antenna is at least partially disposed in the pipe fitting and is operative to receive the transmitted data. Lastly, the data processor is in data communication with the antenna. In one or more embodiments, the system may be a wastewater treatment system, and the data from the sensor may facilitate monitoring and control of the wastewater treatment system.

Description

TELEMETRY FOR WASTEWATER TREATMENT

SYSTEMS AND THE LIKE

FIELD OF THE INVENTION

The present invention relates generally to telemetry and industrial automation, and, more particularly, to monitoring and control systems for applications that utilize submerged piping to transport gases, such as wastewater treatment systems.

BACKGROUND OF THE INVENTION

Diffusers are conventionally used to support aerobic biological processes in aerated wastewater treatment systems. A diffuser typically comprises a disc-, tube-, or strip-shaped membrane that is constructed of rubber or other similar materials and which is punctured to provide a number of perforations in the form of holes or slits. In operation, pressurized air is sent through these perforations to create a plume of small bubbles. The bubbles rise through the wastewater and, in so doing, provide the surrounding wastewater with the oxygen needed to sustain the desired biological processes occurring therein. The rising bubbles also provide a mixing function.

FIG. 1 shows a partially cutaway perspective view of a fine bubble diffuser 100 that might be used in a wastewater treatment facility. Wastewater treatment with such diffusers is described in, as just one example, F.L. Burton, Wastewater Engineering, McGraw-Hill College, 2002, which is hereby incorporated by reference herein. In the diffuser 100, a flexible diffuser membrane 110 sits atop a diffuser body 120. The diffuser body comprises a threaded connector 130, an air inlet pipe 140, an orifice 150, and a receiving surface 160 for coupling to a retainer ring 170. The retainer ring 170 holds the flexible diffuser membrane 110 against the diffuser body 120. When gas is applied to the flexible diffuser membrane 110 through the air inlet pipe 140 and the orifice 150, the gas pressure expands the diffuser membrane 110 away from the diffuser body 120 and causes the membrane's perforations to open so that the gas discharges through them in the form of fine bubbles. When the gas pressure is relieved, the flexible diffuser membrane 110 collapses on the diffuser body 120 to close the perforations and prevent the liquid from entering the diffuser body 120 in the opposite direction. Generally, a flexible diffuser membrane configured in this way produces bubbles smaller than five millimeters in diameter. The resultant large ratio of surface area to volume in these bubbles promotes efficient oxygen mass transfer between the bubbles and the wastewater. In use, the above-described diffusers are typically supplied with pressurized air by a network of piping that covers most of the floor of a wastewater treatment tank. In addition to the diffusers, the network of piping may also include ancillary equipment such as moisture purge systems and pressure monitoring systems. Nevertheless, a wastewater treatment tank is a harsh and dynamic environment, and piping and diffusers periodically fail as a result. Extreme temperature deviations and the resultant thermal expansion/contraction of thermoplastic parts, as well as unwanted vibrations (e.g., air hammering), may, for example, cause a pipe sidewall, joint, end cap, or support anchor to fail. At the same time, leaks may form in the piping, resulting in undesirable water or sludge buildup inside the network that can drastically affect system efficiency.

While these several failure modes exist in almost every aerated wastewater treatment system, there is a general lack of effective ways of monitoring these systems and detecting small problems early before they turn into catastrophic failures. The typical method of monitoring the health of an installed aeration system consists of looking for: 1) changes in surface bubble and water flow patterns; 2) the existence of water or sludge in a moisture purge line that connects to the network of piping under the surface; 3) an increase in the air pressure required to maintain a given rate of air transport through the network of diffusers; 4) a change in dissolved oxygen in one or more zones of a tank as measured by dissolved oxygen probes; 5) a change in effluent quality as measured by parameters such as biochemical oxygen demand concentration or ammonia concentration; and 6) an increase in air volume required to maintain a steady dissolved oxygen concentration in the wastewater. Nevertheless, these are all macro indicators. In other words, they may indicate serious problems such as diffuser membrane fouling, water or sludge in the pipes, or an aeration system that is otherwise compromised, but, at that point, the problem is already causing disruption to the system performance either in a failure to provide efficient treatment or a failure to provide high quality effluent.

For the foregoing reasons, there is a need for systems and methods for effectively providing early detection of defects in aerated wastewater treatment systems and other systems that utilize submerged pipes for the transport of gases before those defects become more serious failures and result in system disruption.

SUMMARY OF THE INVENTION

Embodiments of the present invention address the above-identified needs by providing methods and apparatus for monitoring and controlling wastewater treatment systems. Aspects of the invention are directed to a system comprising a tank, a pipe, a pipe fitting, a sensor, an antenna, and a data processor. The pipe is disposed in the tank and is operative to transport a gas. The pipe fitting is fixated to the pipe. The sensor is located in the pipe and is operative to transmit data via radio. The antenna is at least partially disposed in the pipe fitting and is operative to receive the transmitted data. Finally, the data processor is in data communication with the antenna.

Additional aspects of the invention are directed to a system comprising a tank, a pipe, a pipe fitting, a sensor, a signal wire, and a data processor. The pipe is disposed in the tank and is operative to transport a gas. The pipe fitting is fixated to the pipe. The sensor is located in the pipe fitting. The signal wire is attached to the sensor. Finally, the data processor is in data communication with the sensor at least in part via the signal wire.

Even additional aspects of the invention are directed to a system comprising a pipe, a diffuser body, a flexible diffuser membrane, and a sensor. The pipe is operative to transport a gas. The diffuser body is mounted on, and is in gaseous communication, with the pipe. The flexible diffuser membrane is supported by the diffuser body. Lastly, the sensor is operative to measure pressure between the flexible diffuser membrane and the diffuser body.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features, aspects, and advantages of the present invention will become better understood with regard to the following description, appended claims, and accompanying drawings where:

FIG. 1 shows a partially cutaway perspective view of a conventional diffuser unit;

FIG. 2 shows a block diagram of a Wastewater Treatment Monitor and Control System (WTMCS) in accordance with an illustrative embodiment of the invention;

FIG. 3 shows a partially cutaway perspective view of a portion of a first illustrative wastewater treatment system for use in the FIG. 2 WTMCS;

FIG. 4 shows a block diagram of an illustrative pressurized air delivery system for use in the FIG. 3 wastewater treatment system;

FIG. 5 shows a partially cutaway perspective view of an illustrative sensor for use in the FIG. 3 wastewater treatment system;

FIG. 6 shows another block diagram of aspects of the FIG. 2 WTMCS;

FIG. 7 shows a block diagram of an illustrative data processor in the FIG. 2 WTMCS; FIGS. 8A and 8B show a side elevational view and a magnified perspective view, respectively, of a portion of a second illustrative wastewater treatment system for use in the FIG. 2 WTMCS;

FIG. 9 shows a block diagram of an illustrative wireless sensor, in accordance with an illustrative embodiment of the invention;

FIGS. lOA-lOC show a top elevational view, a sectional view, and a perspective view, respectively, of a portion of a third illustrative wastewater treatment system for use in the FIG. 2 WTMCS;

FIG. 11 shows an exploded perspective view of an illustrative wireless sensor for use in the FIG. 10 wastewater treatment system;

FIG. 12 shows a sectional view of a pipe tee in the FIG. 10 wastewater treatment system;

FIG. 13 shows a block diagram of the FIG. 10 wastewater treatment system;

FIG. 14 shows a partially cutaway perspective view of the FIG. 1 diffuser with the addition of a differential pressure sensor, in accordance with an illustrative embodiment of the invention; and

FIG. 15 shows a perspective of a partially solar powered interface box.

DETAILED DESCRIPTION OF THE INVENTION

The present invention will be described with reference to illustrative embodiments. For this reason, numerous modifications can be made to these embodiments and the results will still come within the scope of the invention. No limitations with respect to the specific embodiments described herein are intended or should be inferred. Moreover, while the illustrative embodiments described herein are directed at applications related to wastewater treatment, aspects of the invention are more generally applicable to any application that utilizes submerged or buried pipes to transport gas.

FIG. 2 shows a block diagram of a Wastewater Treatment Monitor and Control System (WTMCS) 200 in accordance with an illustrative embodiment of the invention. The WTMCS 200 can be conceptually broken into several subsystems: a wastewater treatment system 205, a treatment system interface 210, a computer network 215, and a user interface 220. Each of these subsystems is further described below.

FIG. 3 shows a partially cutaway perspective view of a portion of a first illustrative wastewater treatment system 205 for use in the WTMCS 200. The wastewater treatment system 205 comprises a tank 300 operative to hold wastewater intended for treatment. At the bottom of the tank 300, a plurality of diffusers 305 are supported by, and in gaseous communication with, a network of pipes 310. These pipes 310 are supplied with pressurized air via a vertical drop pipe 315. Once properly pressurized, the diffusers 305 emit plumes of small bubbles into the wastewater (see Background). In the present embodiment, the diffusers 305 are disk-shaped fine bubble diffusers similar to the fine bubble diffuser 100 shown in FIG. 1 , but in other embodiments, the diffusers 305 may just as easily be tubular, strip-shaped, or of another variant.

The pressurized air is delivered to the distribution pipes 310 of the wastewater treatment system 205 via a pressurized air delivery system. FIG. 4 shows a block diagram of an illustrative pressurized air delivery system 400 for use in the wastewater treatment system 205. In this particular, non-limiting embodiment, air is filtered by an air filter 405 and then pressurized by an air blower 410. After leaving the air blower 410, the pressurized air is transported to a pressure regulator 415, which acts to set the pressurized air at a predetermined pressure. The pressure- regulated pressurized air is then distributed to a set of separately controllable air valves 420. The air valves 420 are preferably fitted with valve actuators, which allow them to be controlled in an automated manner (e.g. electric, pneumatic, hydraulic). Such actuated valves are commercially available from, as just one illustrative source, PetroChem Valve, Inc. (Alvin, TX, USA). In the present example, only three such air valves 420 are shown, but this number is merely illustrative and any number of air valves may ultimately be utilized when reducing aspects of the invention to practice. The air valves 420 determine how the pressurized air is distributed between several different grids of the pipes 310, which act to define separately regulatable aerobic zones within the tank 300 of the wastewater treatment system 205. In this manner, a portion of the tank 300 can be maintained at a greater or lower volumetric flow rate of pressurized air than another portion, ultimately providing finer control of the wastewater treatment process.

Referring again to FIG. 3, several sensors 320 are coupled to the pipes 310 in the tank 300. Each sensor 320 is in data communication with an interface box 325 via a respective signal/power wire 330, which is routed to an interface box 325 via a wire conduit 335 located on the side of the tank 300. Here again, just three illustrative sensors 320 are shown, but in actual reduction to practice, a substantially different number of sensors 320 (e.g., many more than three) may be utilized. FIG. 5 shows a partially cutaway perspective view of a representative one of the sensors 320 mounted to the pipe 310. The sensor 320 comprises a dome-shaped, waterproof housing 500 that encapsulates sensor circuitry within (not visible). The signal/power wire 330 emanates from the top of the housing 500. At the bottom of the housing 500, a threaded attachment point 505 allows the sensor 320 to be readily coupled to oppositely threaded holes in the pipe 310. In this manner, the housing 500 of the sensor 320 is disposed outside the pipe 310, but the sensor 320 is operative to measure characteristics occurring inside the pipe 310. Elastomeric O-rings or other means of obtaining a watertight seal can be used as necessary. In addition, rather than utilizing threads for attachment, several other attachment means may be utilized (e.g., gluing, fusing, solvent welding, clamping, bolting), which will be readily apparent to one skilled in the art.

The sensors 320 are variously operative to determine a characteristic of the pipes 310 or the gas that is transported through the pipes 310. These characteristics include, but are not limited to, temperature, pressure, vibration (e.g., count and severity), relative humidity, gas velocity, gas volume, and gas composition. Process measurements via telemetry are generally described in D.O. deSa, Instrumentation Fundamentals for Process Control, Taylor and Francis, 2001, which is hereby incorporated by reference herein. Moreover, suitable sensor circuitry for the applications described herein is commercially available. One source is, for example, Omega Engineering Inc. (Stamford, CT, USA). Another source is, as another example, Honeywell Sensing and Control (Golden Valley, MN, USA).

FIG. 6 provides a block diagram that reveals additional aspects of the illustrative WTMCS 200. The treatment system interface 210 can be conceptually separated into a power supply 600, a sensor interface 605 , a control interface 610, and a data processor 615. In the present exemplary embodiment, these elements are physically located in the interface box 325 positioned proximate to an edge of the tank 300 (FIG. 3), although such positioning is by no means limiting. The sensor interface 605 receives the data signals from the sensors 320 via the signal/power wires 330 and, in return, provides power to the sensors 320 that is generated by the power supply 600. The sensor interface 605 may also amplify, digitize, and otherwise modify the data signals as required. Additionally, if some or all of the data signals are multiplexed, the sensor interface 605 may perform any required demultiplexing. Once the data signals from the sensors 320 are properly conditioned, the sensor interface 605 sends the data to the data processor 615.

Additional aspects of the data processor 615 are shown in a block diagram in FIG. 7. The data processor 615 comprises a data processing unit 700, a memory 705, and a network interface 710. The memory 705 (non-volatile and/or volatile) stores a basic input/output system (BIOS) 715, an operating system (OS) 720, and application programs 725. Some of the application programs 725, when executed by the data processing unit 700, preferably allow the data processor 615 to act as a web server. A web server is capable of receiving conventional Hypertext Transfer Protocol (HTTP) requests from a remote computing device and providing a HTTP response to that computing device over a suitable Internet Protocol (IP) network connection. This functionality allows the uploading and downloading of documents, application programs, and raw data to and from the data processor 615. Data may be provided in several formats including in an extensible markup language (XML) format. Web servers are widely implemented in computers and computer-like devices, and thus their implementation in the data processor 615 will be familiar to one skilled in the art. Details of configuring a web server are also provided in L. Shklar et al., Web Application Architecture: Principles, Protocols and Practices, Wiley, 2003, which is hereby incorporated by reference herein.

Returning back to FIG. 6, the data processor 615 transmits its information to the computer network 215 (e.g., the Internet) via the network interface 610. Data transmission from the data processor 615 to the computer network 215 may be by wires, wirelessly, or some combination of the two. A wired connection may, for example, comprise an Ethernet connection. Wireless communication may comprise communication by, for example, a Wi-Fi, cellular, or satellite connection.

In addition to supplying power to the sensors 320, the power supply 600 may also supply power for the sensor interface 605, the control interface 610, and the data processor 615. While it is contemplated that the power supply 600 will predominantly run on line power, it may also be fitted with one or more batteries that can continue to power the treatment system interface 210 and sensors 320 in case line power is lost.

The user interface 220 comprises local user interfaces 620 and remote user interfaces 625. These user interfaces 620, 625 may access the data available on the computer network 215 to provide a local or remote user with essentially real-time diagnostics about the functioning of the wastewater treatment system 205. Each of the user interfaces 620, 625 may comprise any device or devices capable of accessing the information provided by the data processor 615. They may therefore include, for example, personal computers, laptop computers, tablet computers, cellular telephones with web-browsing capabilities, and the like. Data can be displayed on the user interfaces 620, 625 via browser programs that access the web content (e.g., web pages) provided by the data processor 615. In addition, or alternatively, purpose-specific software programs running on the local and remote user interfaces 620, 625 can display the desired information. In the latter case, application programming interfaces (APIs) and software development kits (SDKs) are preferably made available to software developers so that these developers can create state of the art applications that facilitate and leverage upon the data made available by the sensors 320.

With the real-time diagnostics of a wastewater treatment system 205 available from the sensors 320, it becomes possible to utilize that sensor data not just for diagnostic and predictive purposes, but also to allow the data processor 615 to actually control the wastewater treatment system 205 in response to the diagnostics. Accordingly, additional application programs 725 in the data processor 615 preferably allow the data processing unit 700 to analyze the sensor data and to issue control commands to automated hardware within the WTMCS 200 in response to that data. Communication between the data processor 615 and the automated hardware is via the control interface 610 (FIG. 6), which acts to convert digital commands received from the data processor 615 into appropriate control signals for the automated hardware. If it is assumed, for example, that the WTMCS 200 comprises actuated air valves 420 like those described with reference to FIG. 4, the control interface 610 may send signals to these automated air valves 420 over an analog loop (e.g., using the 4-20 mA analog signaling protocol) or over a digital loop (e.g., using a Foundation Fieldbus, Profibus, DeviceNet, Hart, or Pakscan digital network). Automation of a valves and the like is commonly utilized in industrial applications and is described in, for example, T.L.M. Bartelt, Industrial Automated Systems: Instrumentation and Motion Control, Cengage Learning, 2010, which is hereby incorporated by reference herein. The data processor 615 can thereby control the various aerobic zones of the wastewater treatment system 205 in response to real time diagnostic information received from the sensors 320. Moreover, because the data processor 615 is also operative to communicate with remote users via the remote user interfaces 625, the WTMCS 200 gives remote users the ability to control the wastewater treatment system 205, to at least some extent, while located away from the physical plant.

While individual sensors 320 were distributed at spaced-apart locations in the wastewater treatment system 205, alternative wastewater treatment systems may place a plurality of sensors at one location. Such a clustering of sensors may reduce the complexity of sensor placement, wiring, and maintenance. FIG. 8 A shows a side elevational view of a portion of a second illustrative wastewater treatment system 205' that utilizes this kind of clustering and may be implemented in the WTMCS 200 (FIGS. 2 and 6). FIG. 8B shows a magnified perspective view of the region marked in FIG. 8 A. Like the wastewater treatment system 205, the wastewater treatment system 205' includes a tank 800 with a manifold pipe 805 that is fed pressurized air by a vertical drop pipe 810. Manifold pipes 815, in turn, branch off of the manifold pipe and feed diffusers 820. In the wastewater treatment system 205', however, a plurality of sensors are located in an end cap 825 of the lateral pipe 805. A wire 830 from the sensors exits the end cap 825 through a grommet 835, which is positioned in an opening in the end cap 825. The grommet 835, which may be made of rubber, acts as a form of "feed-through." The wire 830 is then routed to an interface box 840 via a wire conduit 845, which runs vertically up a sidewall of the tank 800. It is noted that while the single wire 830 is shown in FIGS. 8A and 8B, the wire 830 may, in actual reduction to practice, comprise a bundle of wires.

While the illustrative embodiments described above utilizes a particular wired sensor configurations (FIG. 5), there are many alternative sensor configurations that may also be utilized to measure characteristics of submerged piping or the gases transported therein, and these many alternative configurations would also fall within the scope of the present invention.

Sensors that communicate with the sensor interface 605 via hybrid wired/wireless arrangements, for example, may be of particular benefit because of their reduced use of wires and thus their easier deployment. FIG. 9 shows a block diagram of an illustrative wireless sensor 900, in accordance with an illustrative embodiment of the invention. The wireless sensor 900 comprises microprocessor circuitry 905, sensor circuitry 910, power circuitry 915, and input/output circuitry 920.

The various components of the wireless sensor 900 may be sourced commercially, and then mixed and matched to produce the desired functionality. In one or more embodiments, for example, the wireless sensor 900 may be fabricated at least in part utilizing microcontroller boards and shields (i.e., printed circuit expansion boards) available from Arduino (Torino, Italy) in combination with sensor circuitry that may be purchased from vendors such as Digikey Corporation (Thief River Falls, MN, USA) and Mouser Electronics (El Cajon, CA, USA). Producing wireless sensors in this manner will be familiar to one skilled in the relevant arts. Moreover, producing wireless sensors is also described in a number of readily available publications including R. Faludi, Building Wireless Sensor Networks, O'Reilly Media Inc. 2010; and T. Igoe, Making Things Talk: Using Sensors, Networks, and Arduino to See, Hear, and Feel Your World, O'Reilly Media Inc. 2011. These publications are both hereby incorporated by reference herein.

In the wireless sensor 900, the sensor circuitry 910 acts to provide data to the microprocessor circuitry 905 concerning one or more physical conditions. In a manner similar to the wired sensors 320 discussed above, for example, the sensor circuitry 910 in the wireless sensor 900 may provide one or more of temperature, pressure, vibration, relative humidity, gas velocity, gas volume, and gas composition. The sensor circuitry 910 may, in addition, provide data on the absence or presence of water (i.e., the sensor may indicate flooding), and gyroscopic forces. In even one or more embodiments, the sensor circuitry 910 may provide data on the flexing (e.g., bending) of pipes or may provide video data via a video camera, including infrared video. It is noted that video sensing is of particular interest because it allows an operator to visually verify data received from other types of sensors, such as vibration, flooding, or flex sensors. Nevertheless, it is emphasized that this list of sensor circuitry is not intended to be limiting. In actual reduction to practice, the wireless sensor 900 may incorporate any number of different sensors capable of measuring physical characteristics of a pipe or a gas inside that pipe, and the results would still fall within the scope of the invention. The power circuitry 915 acts to provide power to the wireless sensor 900. In one or more embodiments, for example, the power circuitry 915 may contain a battery and/or a means of scavenging power from an interrogation signal. The battery may be rechargeable. Moreover, the power circuitry 915 may obtain power from a wire such as an Ethernet cable or a Universal Serial Bus (USB) cable.

The input/output circuitry 920 acts to receive interrogation signals intended for the wireless sensor 900, and to also transmit data from the wireless sensor 900. Bluetooth, ultra-wideband (UWB), ZigBee, and Wi-Fi are four exemplary, but non-limiting, protocol standards for short range wireless communications with low power consumption. Bluetooth, UWB, ZigBee, and Wi- Fi are variously described in specifications promulgated by the Institute of Electrical and Electronic Engineers (IEEE), namely, IEEE 802.15.1, 802.15.3, 802.15.4, and 802.11, respectively. Bluetooth operates in the 2.4 gigahertz (GHz) frequency band; UWB operates in the 3.1-10.6 GHz frequency band; Zigbee operates in the 868/915 megahertz (MHz) and 2.4 GHz frequency bands, and Wi-Fi operates in the 2.4 and 5 GHz frequency bands.

Although not limiting, the wireless sensors 900 may utilize a radio frequency identification

(RFID) technology in combination with suitable sensor circuitry and probes. That is, the wireless sensors 900 may comprise RFID tags. The combination may then transmit their measurement data along with identifying information that identifies the sensors. RFID sensor technology is described in, for example, A. Rida et al, RFID-Enabled Sensor Design and Applications, Artech House, 2010, which is also hereby incorporated by reference herein. Suitable equipment may be obtained from several vendors including, for instance, GAO RFID Inc. (Toronto, ON, Canada) and Phase IV Engineering, Inc. (Boulder, CO, USA). RFID tags may be passively powered, that is, they may not include batteries, but may instead scavenge power from interrogation signals.

FIGS. lOA-lOC show various views of a portion of a third wastewater treatment system 205" that may be incorporated into the WTMCS 200 indicated in FIGS. 2 and 6 in the place of the wastewater treatment system 205. FIG. 10A shows a top elevational view, while FIG. 10B shows a sectional view along the plane indicated in FIG. 10A, and FIG. IOC shows a perspective view.

The wastewater treatment system 205" comprises a tank 1000 with a manifold pipe 1005 and a plurality of lateral pipes 1010 that branch therefrom. Each lateral pipe 1010 joins the manifold pipe 1005 at a respective pipe tee 1015. The manifold pipe 1005 receives pressurized air from a vertical drop pipe 1020 that runs down a sidewall 1025 of the tank 1000. An interface box 1030 containing the treatment system interface 210 is positioned at a top corner of the tank 1000. Diffusers 1035 and wireless sensors 1040 are regularly arranged along each of the lateral pipes 1010. A representative positioning of wireless sensors 1040 is shown in FIG. 10A, with the position of each wireless sensor 1040 indicated by where dashed lines marked "T" and "V" intersect the lateral pipes 1010. In this particular exemplary embodiment, the wireless sensors 1040 are variously capable of providing vibration (V) and temperature (T) information, but this selection and their particular arrangement is merely by way of example. In alternative embodiments, different sensors may be added to or substituted for those indicated, and different positioning may be utilized.

In the present, non- limiting embodiment, the wireless sensors 1040 in the wastewater treatment system 205" are of the kind discussed above with respect to the wireless sensor 900 in FIG. 9. With regard to physical characteristics, at least some of the wireless sensors 1040 are in the form of wireless cards encapsulating sensor circuity supported by two short and narrow sections of mounting pipe. This configuration is best seen in an exploded view of a representative wireless sensor 1040 in FIG. 11, with a wireless card 1100 adhered onto two mounting pipes 1105. When placing the wireless sensor 1040, the mounting pipes 1105 are preferably adhered to the inside of one of the lateral pipes 1010 with the wireless card 1100 elevated off the sidewall of that lateral pipe 1010. Aligning the bores of the mounting pipes 1105 with the flow of air helps to reduce the impact that the wireless sensor 1040 has on that air flow. At the same time, if there is minor flooding, the wireless sensor 1040 may be spared by being raised off of the inside sidewall of the lateral pipe 1010. It is noted that, for smaller wireless sensors 1040, only a single mounting pipe 1105 may be used for mounting the wireless sensor 1040 to one of the lateral pipes 1010. For larger wireless sensors 1040, more than two mounting pipes 1105 may be utilized.

It has been empirically determined by the inventors that radio transmissions of the type contemplated herein may be impeded by the water that surrounds the piping in a wastewater treatment system when attempting to transmit through the liquid, as well as by bends in that piping when attempting to transmit through the air in the piping. As a consequence of this discovery, the wastewater treatment system 205" utilizes a unique arrangement of interrogation/data-collection antennas (IDCAs), which are positioned in each of the pipe tees 1015. An exemplary one of these IDCAs 1045 is shown in FIG. 12, which shows a sectional view along the plane indicated in FIG. IOC. As indicated in FIG. 12, the representative IDCA 1045 is positioned in a respective one of the pipe tees 1015 and protrudes somewhat into the respective lateral pipe 1010 that projects from that particular pipe tee 1015. Line-of-sight (LOS) is therefore created between the IDCA 1045 and the wireless sensors 1040 positioned in the particular lateral pipe 1015 that branches from the pipe tee 1015 in which the IDCA 1045 is disposed. This arrangement is replicated for each of the pipe tees 1015, essentially "associating" a respective IDCA 1045 with each lateral pipe 1015 and its wireless sensors 1040. As a result, radio frequency communication between each IDCA 1045 and its associated wireless sensors 1040 is through air (rather than liquid) and with LOS, mitigating the above-described attenuation that would be present if the two were separated by water or bends in the piping. A respective wire 1050 is attached to each of the IDCAs 1045, and exits the pipe tee 1015 through a grommet 1055 on the way to the interface box 1030. On their way up the sidewall 1025 of the tank 1000, the wires 1050 are routed by vertical wire conduits 1060 that are placed vertically on the sidewall 1025 of the tank 1000 above each pipe tee 1015. Upon reaching the top edge of the tank 1000, the wires 1050 are further routed by a lateral wire conduit 1065 that directs the wires 1050 to the treatment system interface 210 in the interface box 1030.

The modified block 205" may be substituted for the block 205 in FIGS. 2 and 6, while leaving the remainder of the WTMCS 200 as before. The alternative wastewater treatment system 205" therefore includes the IDCAs 1045 and the wireless sensors 1040 (as well as the air valves 420). This configuration is indicated in the block diagram in FIG. 13. Because it is contemplated that a large wastewater treatment system may comprise a multiplicity of IDCAs 1045, an antenna multiplexer may be incorporated into the sensor interface 605 of the treatment system interface 210, and demultiplexers may be provided at the IDCAs 1045. Use of the multiplexor and the demultiplexers can reduce the number of wires that span between the sensor interface 605 and the IDCAs 1045.

As their name would suggest, the IDCAs 1045 serve two functions in the WTMCS 200.

They both interrogate the wireless sensors 1040 to elicit responses from those wireless sensors 1040, as well as receive wireless data transmitted by those wireless sensors 1040 in response to the interrogations. The wireless sensors 1040 may transmit identifying information (e.g., a media access control (MAC) address, electronic ID (EID), or similar) as well as their payload. The payload may contain the sensor data, but may also contain other data such as power status, fault codes, trends, etc. If so desired, the data provided by the wireless sensors 1040 may be encrypted to avoid issues with unauthorized access. The data received from the wireless sensors 1040 by the IDCAs 1045 is transmitted to the sensor interface 605 of the treatment system interface 210 via the wires 1050.

In actual reduction to practice, the IDCAs 1045 may interrogate the wireless sensors 1040 continuously or periodically. Periodic interrogation (i.e., once every predetermined amount of time) reduces power consumption by the wireless sensors, and is therefore preferred if the wireless sensors are operated on battery power. Additional battery power may also be saved by programming the wireless sensors 1040 to only respond when there is a predetermined change in sensor measurements. This is implemented via a logging function in the wireless sensors 1040, wherein each wireless sensor 1040 compares its present measurement to one or more past measurements stored in memory. The memory may be part of the microprocessor circuitry 905. A given wireless sensor 1040 capable of measuring temperature may, as just one example, be programmed to only respond to an interrogation if the temperature has changed by more than one degree Celsius. If the wireless sensors 1040 are on wired power, reduced power consumption is less of a concern.

It is noted, that while the IDCAs 1030 occupy the pipe tees 1015 in the above-described wastewater treatment system 205", in alternative embodiments, the IDCAs 1040 may occupy other forms of pipe fittings such as, but not limited to, cross tees, elbows, and side outlet elbows.

Embodiments of the present invention provide a number of advantages. A monitor and control system in accordance with aspects of the invention may, for example, allow the kind of automated sensor-based wastewater treatment system control and optimization described above. If, for instance, air velocity sensors indicate that one aerobic zone is experiencing a lower volumetric flow rate of air than desired, a data processor may command that an air valve for that lower-performing aerobic zone be modified to increase its flow rate. In addition, several automated air valves may be coordinated to automatically maintain a desired pattern of dissolved oxygen in the wastewater being treated.

At the same time, a properly distributed array of sensors in a wastewater treatment system may also predict failures, detect failures, and determine maintenance requirements. Air velocity sensors, for example, may help to determine the air distribution uniformity in the system's piping network and thereby allow optimization of pipes and perforation sizes in diffusers to improve efficiency. Temperature sensors may determine the actual temperature of a piping network so as to ascertain if the piping is staying within a safe operating range. Pressure measurements, including those taken near where a diffuser attaches to a distribution pipe or in the air inlet pipe of a diffuser itself (see the air inlet pipe 140 in FIG. 1), can determine back pressure requirements for a diffuser and therefore indicate the level of diffuser fouling. Vibration sensors can determine unsafe air hammering and other sources of vibration that can cause pipe failures and leakage (e.g., broken mounting brackets). Relative humidity measurements can detect water and sludge in the pipes, which is a particular concern in those wastewater treatment systems where the pressurized air is frequently cycled on and off. Lastly, gas composition sensors can indicate the composition of the pressurized air carried in the pipes (e.g., oxygen content).

If sensors were to determine, for example, that a portion of the network of pipes were flooded, a purge valve could automatically be opened to cause the liquid to be expelled from that portion. At the same time, if a leak were detected in a zone of the wastewater treatment system, one or more valves or inflatable bladders could be triggered to either shut off that zone completely or to throttle back the amount of pressurized air that enters that zone. As before, these actions could occur entirely automatically or in consultation with an operator, who would not necessarily need to be on site.

In addition, it may be particularly beneficial to correlate the real-time data provided by sensors in or on the piping of a wastewater treatment system with other real time measurements, such as dissolved oxygen and off-gas respirometry measurements. As the name would suggest, dissolved oxygen measurements determine the amount of oxygen dissolved in wastewater. Off- gas respirometry, in contrast, utilizes one or more hoods located over the surface of wastewater to analyze the gases emitted by that wastewater. Combined, the sensor, dissolved oxygen, and off- gas respirometry data allow one to precisely determine and optimize those factors that affect oxygen transfer efficiency and oxygen uptake rates.

It may also be particularly beneficial to utilize aspects of the invention to determine diffuser dynamic wet pressure (DWP). DWP measures the headloss across a diffuser, and is dependent on the rate of air flow to the diffuser being measured. In the field, DWP is an excellent indicator of the state of diffuser fouling. When a diffuser in use is fouled, its DWP at a given rate of air flow tends to increase significantly above that of a new diffuser. This puts a higher demand on the blower system of the wastewater treatment system and increases the cost of operation. As a result, DWP may be a good determinant of when it would be beneficial to clean or replace a diffuser.

For determining DWP for a disc diffuser of the type shown in FIG. 1 , a differential pressure sensor may be deployed in the manner shown in FIG. 14. FIG 14 shows a partially cutaway perspective view of a differential pressure sensor 1400 attached to the diffuser 100, in accordance with an illustrative embodiment of the invention. The diffuser 100 in FIG. 14 contains the same elements as the diffuser 100 shown in FIG. 1 , and is therefore labeled with like reference numerals. The differential pressure sensor 1400 comprises a sensor housing 1405 (with pressure measuring sensor circuitry within), a first pressure probe 1410, and a second pressure probe 1415. The sensor housing 1405 may be mounted on the outside or the inside of a lateral pipe (not specifically shown), or to the bottom of the diffuser body 120. The first pressure probe 1410 passes through the diffuser body 120 to a point immediately below the diffuser membrane 110. The second pressure probe 1415 accesses the pipe before the air inlet pipe 140 and the orifice 150.

The differential pressure sensor 1400 outputs data indicative of a pressure difference, Pdifference, between the pressure in the pipe (before the orifice 150) and the pressure under the diffuser membrane 120 (after the orifice 150). Once Pdifference, is determined, that value may be utilized to determine DWP by also measuring P_pi_pe (the pressure in the lateral pipe near the diffuser 100) and P_static (the pressure required to cause a bubbler at the height of the diffuser 100 to produce bubbles). With these values, DWP is given by the simple relation: D^VP Ppipe^— Pdifference^— Pstatic-

At the same time, P_pi_pe and Pdifference may also be utilized to determine the rate of air flow through the diffuser 100 utilizing routine calculations for the dependence of air flow rate through an orifice on the pressure drop across the orifice.

Alternative embodiments, moreover, may provide similar information by placing a wireless sensor card like the card 1100 shown in FIG. 11 between the diffuser membrane 110 and the diffuser body 120 of the diffuser 100, and then wirelessly transmitting pressure data to a receiver located nearby. The receiver may, for example, be placed underneath the diffuser 100 inside the associated lateral pipe. The wireless transmission between the wireless pressure sensor card and the reader may be in accordance with any one of many available wireless protocol standards, including, but not limited to, the four exemplary protocol standards set forth above (i.e., Bluetooth, UWB, ZigBee, and Wi-Fi) as well as Low Bluetooth Emittance (LBE). If the transmissions between the wireless sensor card and the receiver are discovered to be unreliable due to attenuation, a portion of an external antenna from the wireless sensor card may be placed so that it passes through the orifice 150 and into the air inlet pipe 140.

While the above-described embodiments relate to wired and wireless sensors for determining characteristics of piping or gases carried in that piping, alternative embodiments of the invention may utilize sensors (wired or wireless) for measuring aspects of the wastewater. Such sensors may measure, as just a few non-limiting examples, pH, temperature, dissolved oxygen, and oxidation-reduction profile. With wired sensors, wires may run from the sensors to an interface box. If the sensors are wireless, sensors in the wastewater may communicate wirelessly with receivers that are mounted inside the piping, and then the data from the receivers may be transmitted via wires to the interface box. In either case, the interface box may optionally be at least partially solar powered, as would also be the case for any of the interface boxes described herein. Such an interface box 1500 with solar panels 1510 is shown in perspective view in FIG. 15.

It will be noted that aspects of the invention may also be applied to telemetry outside of the wastewater treatment space. For example, in one or more embodiments, RFID tags may be attached along the length of pipes before those pipes are buried in the ground. The RFID tags, may, as just one non-limiting example, be placed with one meter spacing. Again, the sensors may appear similar to the sensor card 1100 shown in FIG. 11 , that is, be in the form of thin cards. These sensors may be internal or external to the pipe.

Attachment of the RFID tags to a pipe may be by incorporation of the tags while the pipe is being manufactured, or, alternatively, may occur after manufacture. Many pipes are manufactured via an extrusion process, wherein a heated material is pushed or drawn through a die of the desired cross-section. RFID tags may be incorporated into the pipe while it is still hot and somewhat malleable. Alternatively, RFID tags may be attached to the pipe by an adhesive, or some other form of attachment (e.g., utilizing a fastener).

In any case, after the pipes are buried, the RFID tags allow a user on the surface to determine both where the pipes are located, and who owns the pipes and is therefore responsible for their maintenance and repair. Less dependence can thereby be placed on maps and surveys, which often contain errors, are incomplete, or are not precise enough to readily locate particular pipes.

In closing, it should again be emphasized that the above-described embodiments of the invention are intended to be illustrative only. These numerous alternative embodiments within the scope of the invention will be apparent to one skilled in the art given the teachings provided herein. Moreover, all the features disclosed herein may be replaced by alternative features serving the same, equivalent, or similar purposes, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

Claims

CLAIMS What is claimed is:

1. A system comprising:

a tank;

a pipe disposed in the tank and operative to transport a gas;

a pipe fitting fixated to the pipe;

a sensor located in the pipe and operative to transmit data via radio;

an antenna at least partially disposed in the pipe fitting and operative to receive the transmitted data; and

a data processor in data communication with the antenna.

2. The system of claim 1, further comprising:

an additional pipe disposed in the tank and operative to transport a gas;

an additional pipe fitting fixated to the additional pipe;

an additional sensor located in the additional pipe and operative to transmit additional data via radio; and

an additional antenna in the additional pipe fitting, operative to receive the additional transmitted data, and in data communication with the data processor.

3. The system of claim 2, wherein the pipe fitting and the additional pipe fitting are interconnected by a connecting pipe.

4. The system of claim 1, further comprising wastewater disposed in the tank, wherein the pipe is submerged in the wastewater.

5. The system of claim 1, further comprising a diffuser mounted on, and in gaseous communication with, the pipe.

6. The system of claim 1, wherein the pipe fitting comprises a pipe tee.

7. The system of claim 1, wherein the sensor is operative to detect a characteristic of the pipe or a gas within the pipe.

8. The system of claim 1, wherein the sensor is operative to detect at least one of temperature, vibration, relative humidity, gas velocity, gas volume, gas composition, flooding, gyroscopic force, and flexing.

9. The system of claim 1, wherein the sensor comprises a video camera.

10. The system of claim 1, wherein the antenna and the sensor are in line-of-sight.

11. The system of claim 1 , wherein the sensor comprises sensor circuitry mounted onto a section of mounting pipe that is distinct from the pipe.

12. The system of claim 1, wherein the sensor comprises a radio frequency identification tag.

13. The system of claim 1, wherein the data processor is in data communication with the antenna via a signal wire.

14. The system of claim 13, wherein the signal wire is routed between the antenna and the data processor via one or more wire conduits.

15. The system of claim 1, wherein the sensor is operative to transmit a radio signal in compliance with at least one of Bluetooth, Ultra- Wideband, ZigBee, and Wi-Fi protocol standards.

16. The system of claim 1, wherein:

the antenna is operative to send an interrogation signal to the sensor; and

the sensor is operative to transmit data to the antenna in response to the interrogation signal.

17. The system of claim 16, wherein the sensor is powered at least in part by scavenging power from the interrogation signal.

18. The system of claim 16, wherein the sensor is adapted to respond to the interrogation signal only upon a predetermined change in a sensor measurement.

The system of claim 1, wherein: the system further comprises a valve; and

the data processor is operative to at least partially control the valve at least in part in response to data transmitted from the sensor.

20. A system comprising:

a tank;

a pipe disposed in the tank and operative to transport a gas;

a pipe fitting fixated to the pipe;

a sensor located in the pipe fitting;

a signal wire attached to the sensor; and

a data processor in data communication with the sensor at least in part via the signal wire.

21. The system of claim 20, further comprising a grommet, wherein:

the pipe fitting defines an opening;

the grommet occupies the opening; and

the signal wire passes through the grommet.

22. The system of claim 20, wherein the pipe fitting comprises an end cap.

23. A system comprising:

a pipe operative to transport a gas;

a diffuser body mounted on, and in gaseous communication with, the pipe;

a flexible diffuser membrane supported by the diffuser body; and

a sensor operative to measure pressure between the flexible diffuser membrane and the diffuser body.

24. The system of claim 23, wherein the sensor is operative to transmit pressure data wirelessly.

25. An apparatus comprising:

a buried pipe; and

a radio frequency identification tag disposed in the buried pipe;

wherein the radio frequency identification tag is operative to provide data indicative of ownership of the buried pipe.