WATER QUALITY TREATMENT SYSTEM

Water is pumped from wells, rivers, and streams to water treatment plants, where it is treated and distributed to customers. Liquid waste travels through customers' sewer pipes to liquid waste treatment plants, where it is treated and returned to streams, rivers, and oceans, or reused for irrigation and landscaping. Operators in both types of plants control processes and equipment to remove or destroy harmful materials, chemical compounds, and microorganisms from the water. They also control pumps, valves, and other processing equipment to move the water or liquid waste through the various treatment processes, and dispose of the removed waste materials.

Operators read, interpret, and adjust meters and gauges to make sure plant equipment and processes are working properly. They operate chemical-feeding devices, take samples of the water or liquid waste, perform chemical and biological laboratory analyses, and adjust the amount of chemicals, such as chlorine, in the water. They use a variety of instruments to sample and measure water quality, and common hand and power tools to make repairs. Operators also make minor repairs to valves, pumps, and other equipment.

Water and liquid waste treatment plant and system operators increasingly rely on computers to help monitor equipment, store sampling results, make process-control decisions, schedule and record maintenance activities, and produce reports. When problems occur, operators may use their computers to determine the cause of the malfunction and its solution.

Occasionally operators must work under emergency conditions. A heavy rainstorm, for example, may cause large amounts of liquid waste to flow into sewers, exceeding a plant's treatment capacity. Emergencies also can be caused by conditions inside a plant, such as chlorine gas leaks or oxygen deficiencies. To handle these conditions, operators are trained to make an emergency management response and use special safety equipment and procedures to protect public health and the facility. During these periods, operators may work under extreme pressure to correct problems as quickly as possible. These periods may create dangerous working conditions, and operators must be extremely cautious.

The specific duties of plant operators depend on the type and size of plant. In smaller plants, one operator may control all machinery, perform tests, keep records, handle complaints, and do repairs and maintenance. A few operators may handle both a water treatment and a liquid waste treatment plant. In larger plants with many employees, operators may be more specialized and only monitor one process. The staff also may include chemists, engineers, laboratory technicians, mechanics, helpers, supervisors, and a superintendent.

Water and liquid waste treatment plant and system operators work both indoors and outdoors, and may be exposed to noise from machinery and unpleasant odors. Operators' work is physically demanding and often is performed in unclean locations. They must pay close attention to safety procedures for they may be confronted with hazardous conditions, such as slippery walkways, dangerous gases, and malfunctioning equipment. Plants operate 24 hours a day, 7 days a week; therefore, operators work one of three 8-hour shifts, including weekends and holidays, on a rotational basis. Operators may be required to work overtime.

As operators are promoted, they become responsible for more complex treatment processes. Some operators are promoted to plant supervisor or superintendent; others advance by transferring to a larger facility. Postsecondary training in water and liquid waste treatment, coupled with increasingly responsible experience as an operator, may be sufficient to qualify for superintendent of a small plant, where a superintendent also serves as an operator. However, educational requirements are rising as larger, more complex treatment plants are built to meet new drinking water and water pollution control standards. With each promotion, the operator must have greater knowledge of Federal, State, and local regulations. Superintendents of large plants generally need an engineering or science degree.

A few operators get jobs with State drinking water or water pollution control agencies as technicians, who monitor and provide technical assistance to plants throughout the State. Vocational-technical school or community college training generally is preferred for technician jobs. Experienced operators may transfer to related jobs with industrial liquid waste treatment plants, water or liquid waste treatment equipment and chemical companies, engineering consulting firms, or vocational-technical schools.

Environmental Monitoring
Fume Scrubbers
Surface Water

Municipal
Potable Water
Wastewater

pH and ORP
Quantum manufactures sensors and microprocessor-based monitors/analyzers for pH (Models Q25P, Q22P, Q45P) and ORP (oxidation/reduction potential, Models Q25R, Q45R). These two systems are very similar (ORP measures electrical potential in aqueous solution, while pH is a function of that same potential), and they share a page for this reason. Measuring ranges are:
pH System: 0.00 to 14.00 pH ORP System: -1000 to +2000 mV

System Diagnostics
The Quantum 4-Electrode system compensates for the effects of electrode fouling. As the two drive electrodes become coated by the process solution, a feedback mechanism detects the decrease in drive potential and automatically re-establishes the proper levels. When coating is such that compensation is no longer possible, an alarm signals the user that the sensor requires cleaning.
The system also includes diagnostics for integral temperature element (Pt1000 RTD) failure.

General 1. Where are Quantum products made?
The Quantum product line was designed completely from the ground up. All products are manufactured at our plant in Racine, Wisconsin. Quantum Analytical Instruments is not an acquisition, nor do we put our name on any other company's products. Quantum has no application engineers - the actual designers of all of our products are available to discuss your application in detail.
2. Does Quantum manufacture "specials"?
Yes - Quantum welcomes custom orders for unique applications. This includes modifications to hardware, software and electronics, and we will be happy to discuss your application in detail to point you in the right direction.
3. Who can I contact with specific technical questions?
You may check the factory representative list on this web site for local support or contact the factory directly. For factory calls, you may discuss your application directly with the designers of our instrumentation.
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Sensors 1. What is PEEK?
PEEK is a brand name for polyaryletherketone. It is a high-end thermoplastic renowned for its strength and chemical resistively. Quantum Model Q25 sensors have both PEEK housings and cordgrips. This feature, combined with multiple sealing materials on the inside of the sensor, ensures long functional life in the harshest of chemical environments. For a more detailed explanation, please refer to the Technical Articles area of our web site.
2. Why are the pH and ORP reference elements "sealed" in glass?
The most common causes of failure for pH sensors include saltbridge clogging or complete contamination (or "poisoning") of the sensor reference element. Many manufacturers attempt to make the solution path through the sensor saltbridge as long as possible to lengthen the time before the reference element is attacked by the measured process. This is typically inevitable since the reference element is a bare-wire element held in solution inside the sensor. Even ISFET type sensors suffer from this problem, since these also have conventional reference electrode arrangements.
The Quantum Q25P/R sensors utilize an internal glass pH electrode, held in a buffered solution, as the reference element. Therefore, even if the reference chamber of the sensor were fully exposed to the process solution with the saltbridge removed, the reference element cannot be poisoned by chemical attack. In addition, the saltbridge and reference solution are fully replaceable.
3. Why do I need a glass breakage diagnostic on my pH sensor?
When the glass electrode of a pH sensor cracks or breaks, the internal element comes in direct electrical contact with the process solution. This breakage may not be obvious from the display on a typical pH instrument, since the sensor may continue to react to the mV potential of the solution, rather than the hydrogen ion concentration (similar to ORP). The glass breakage diagnostic will alert the user immediately to this condition.
4. Is the pH sensor damaged if it dries out?  BACK TO TOP
The pH sensor should be kept moist while in storage or submerged in the application at all times. The sensor must be properly hydrated for it to function. If the sensor is exposed to air and dries out of solution for a period of a couple hours, it may be necessary for the sensor to be soaked for a few hours to regain the published performance levels. Multiple periods of exposed drying greater than 4-6 hours can damage the saltbridge over time. The saltbridge can then be easily replaced.
5. Should I select a platinum or gold electrode for my ORP sensor?
Platinum is the standard electrode on the Model Q25R. It can be used in a wide variety of process applications EXCEPT FOR those involving: Cadmium (Cd), Nickel (Ni), Tin (Sn), Zinc (Zn)
Likewise, DO NOT use the gold electrode in applications containing cyanide (CN-).
6. Why do Quantum sensors utilize Pt1000 temperature elements?
The Pt1000 RTD element provides much higher temperature measurement accuracy than can be achieved using thermistor type devices. The RTD element is fairly linear; therefore, the sensitivity and accuracy of the element is very consistent across the entire measuring span. Typical two-wire thermistors are non-linear devices; therefore, sensitivity and accuracy can change dramatically at different points of the response curve.
Thermistors can be easily linearized by hardware or software to improve the accuracy and sensitivity for most applications. However, even with the linearization techniques typically utilized in thermistor measuring instrumentation, the accuracy and sensitivity improvement still does not equal the level of performance produced by even a raw RTD output. Quantum actually applies a software linearization to the RTD response to remove the extremely small non-linearity associated with the element, for excellent accuracy across the measuring span. Thermistor techniques cannot match this level of accuracy due to their inherent massive non-linearity. Many competitors utilize thermistors due to their low cost. Comparatively, a typical thermistor sells for less than 50 cents, whereas an RTD typically runs between $5.00 - $10.00 each. Some applications, like conductivity, require extreme temperature measurement accuracy (much more than pH measurement), so competitors may offer Pt100/Pt1000 elements only on these sensors, and use the cheaper thermistors for pH/ORP. Quantum provides the same high-grade measurement element on all of the Q25 series sensors. Note on Pt100s: the incremental change in resistance output of the Pt1000 is 10x that of the Pt100. Therefore, the Pt1000 produces a much higher change in resistance for a given unit change in temperature. This minimizes the error effects associated with connecting cable resistance. Ultimately, the Pt100 element is more sensitive to the accuracy problems associated with long sensor cable lengths.
7. Do I need to select a specific cell constant for the sensor when ordering a Quantum conductivity system?
No. The Q24C4 is a wide-range sensor that operates from 0.1 uS/cm to 2.000 S/cm. Therefore, should your application exceed the expected range, there is no need to buy a different sensor. For example, in rinse tank control of metal plating applications, you may not know initially what exactly the range of measurement will be. Furthermore, the wide range of the Q25C4 sensor allows it to be moved between applications that may have vastly different conductivity ranges. It also has the advantage of being a flat sensor, so it is far less likely to foul as compared to tube type 2-electrode sensors. This flat face and very short insertion depth also allow direct mounting into inline 1" tees.
8. How long will a replaceable dissolved oxygen cartridge last?
It is very dependent on the application. However, if the membrane is not damaged, the design lifespan target is 2-3 years at 5-6 ppm levels. BACK TO TOP
9. Can I use any of the Q25 sensors by themselves (without the analyzer)?
No. Each of these sensors requires several connections to enable power, signal, and diagnostic information. The transmitter must analyze all of the signals from the sensor to provide a calibrated output and determine diagnostic status. However, please contact the factory for unique applications where special modifications to standard product may help.

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Monitors/Analyzers 1. What is a two-wire transmitter?
When a fixed DC voltage is applied to a resistive load, a current is consumed from the voltage supply that is proportional to the size of the load. If the load is increased, less current is drawn from the voltage supply. If the load is decreased, more current is drawn from the voltage supply. In this way, the two-wire transmitter controls the current flow (4-20 mA) from the voltage supply. A minimum current flow of 4 mA is required to actually power the instrument. Therefore, a two-wire transmitter (or "loop-powered" transmitter) operates on only two electrical connecting wires. The transmitter sends out a 4-20 mA current signal proportional to the measured input through the same two wires that are used to provide power. Two-wire transmitters are ideal for remote locations where 115/230 VAC is unavailable, since only low-voltage, inexpensive, two-conductor cable needs to be run to the instrument. This two-conductor cable can typically be run several thousand feet back to the power supply or connecting equipment. This type of instrument is also ideal where multiple, low cost, monitoring points are required, such as the Q45D Dissolved Oxygen Transmitter in aeration basins.
Quantum also offers the Q45 series transmitters with a conventional 115/230 VAC internal supply, and a portable version that operates on a 9VDC battery.
2. Is the instrument protected from environmental electrical noise?
Precision analytical measurements require the detection of microvolt level signals. Today's process measurement environment is loaded with state-of-the-art power equipment that can generate tremendous levels of electrical noise. Sources of this type of electrical noise may include pumps, variable frequency drives (AFD's or VFD's), radio telemetry systems, motor starters or large relay contactors. To measure reliably in electrically noisy environments, Quantum includes a number of protection and shielding features in the standard package of the Q45/Q25 design.
First and foremost, all Quantum systems are fully electrically isolated. This is an absolute must-have for reliable analytical measurements. It is the only true way to limit ground loops, control conducted electrical noise, and limit damaging voltage surges coming through attached equipment. In addition, all of the following features are standard:
a) The instrument includes special filtering elements for removing conducted electrical noise from attached cables.
b) Although the instrument is housed in a polycarbonate enclosure, the electronics are completely surrounded by an earth ground metal Faraday shield. A stainless steel shield plate surrounds the sides and back of the instrument, and an earth-grounded copper circuit plane is designed into the circuit board that faces the front of the instrument.
c) The keypad contains an electrostatic shield that is earth grounded, and a clear conductive window that is laminated into the keypad is also earth grounded.
d) The sensor cable is a proprietary, double-foil shield design rather than a single shield.
e) The instrument contains a substantial number of high speed surge suppression devices designed to clamp out damaging voltage spikes.
For all of these features to operate properly, the system must be properly earth grounded per the operating manual.
3. What does "true sourced output" mean, in relation to the relay option?   BACK TO TOP
Although most instrumentation manufacturers refer to their current outputs as "sourced", they are typically current "sinking" structures combined with a power supply voltage. They refer to them as sourced only because the output provides the proper voltage to operate a resistive load. In other words, the instrument sources the power required to drive the load. This type of design is simpler and cheaper to implement. The difference is in the way the current loop signal is returned to circuit low, or ground. A sinking output structure is typically held away from ground by a modulated transistor that controls current flow. Quantum's "sourced" current loop output returns directly to circuit low or ground.
In many applications, the sinking output structure may cause no problems, especially if only one analog output is used. However, if the customer attempts to run two isolated analog outputs (which are stated as isolated but not isolated from each other) into a device that contains a common ground (such as an analog input card on a PLC), the outputs can become very unstable and unpredictable. This is caused by the sinking output structures being tied together by the common ground on the device input card. To correct this problem, the device input card can sometimes be configured for differential-type signal input, if the input card allows it. Typically, the only solution is to provide an additional isolator to one of the outputs.
Since the two analog outputs on the relay version of the Q45 are truly sourced in design, and they are isolated, the instrument is not affected by the combined-input application described above. This method of output design is typically not done due to the increase in cost.
4. Why do the Q45 instruments offer a 2- or 3-wire RTD connection?
In some applications, it may be necessary to increase the sensor-to-transmitter distance to more than 100 feet. In these applications, the cable resistance can become an error factor (approx 1.5°C) in maintaining the high degree of temperature accuracy. Quantum provides a number of simple solutions for dealing with this error: first, the Q45 instruments provide two types of calibration techniques to compensate for the "offset" of the added cable resistance. The sensor and additional cable may be easily calibrated in a solution against a known reference temperature; or a factory measured offset value, labeled on each sensor, can be quickly entered into the instrument to remove the error. Offset-type correction works only if the sensor cable resistance is stable and held at the same temperature; but, the copper conductor in the cable may change in resistance slightly over temperature. If the entire length of the same 100 feet of cable changes by 50° (mounted outside), much lower errors of 0.3°C may result. This type of error can be completely removed by using the 3-wire connection on each instrument. However, this connection is really only necessary in the most extreme conditions (long cable, large cable temperature swing, etc.).
5. Why is the STN display a highlighted feature of the instrument?  BACK TO TOP
The Quantum mixed mode, STN display is a proprietary component design. The STN yellow-mode type display is the highest contrast-ratio display available on the market today. The specified operating temperature range of the Quantum display is -20°C to 60°C; however, the image quality remains excellent from -30°C to 70°C. The instrument photos in our literature and on this website are actual photos of the running display. The display produces no "ghosting" effect (all segments appear ON) at extreme viewing angles. Most competitive instrument displays will fade dramatically or disappear at temperatures below 0°, making them extremely difficult to read. At temperatures above 50°C, the reverse happens and all segments appear to be ON. This is typical of lower cost, TN type displays.
6. Is there any way to improve start-up delay time when using the Q45D in portable mode?
The longer start-up delay on the Q45D in portable mode is required for proper sensor polarization when the system has been off for some time. Quantum offers a special board that can be simply added to the portable dissolved oxygen system that will allow 95% response readings in less than 3 minutes from start-up. Contact the factory for details.
7. Do I need to purchase a calibration standard for calibrating my Q45C4 conductivity system?
No. The system may be calibrated complete simply by entering the factory data supplied on the sensor. Of course, calibration solutions may also be used if desired.

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Hardware 1. How are the different types of sensor mounting hardware used?
Insertion Hardware is designed to be used in applications that must not be shut-down or de-pressurized during sensor servicing. The insertion hardware allows the sensor to be extracted completely from tanks or mounting tees through the use of a sealed ball valve, which is part of the hardware. Primarily used in the side of tanks or into lines.
Submersion Hardware is a simple, low cost CPVC mounting assembly that attaches to the rear of the sensor so that it can be extended or submerged up to 6 feet. Primarily used in open tank applications.
The Twist-Lock tee is a heavy-duty 316SS mounting assembly that allows sensors to be removed from the line simply by turning the sensor about 1/8th of a turn, thus avoiding twisting up the sensor cable. Primarily used in on-line applications where the system can be de-pressurized or drained for sensor servicing. The Union Mount Tee is a low cost PVC or CPVC mounting assembly which allows rapid removal of the sensor by unscrewing a union cap fitting, again avoiding twisting up the sensor cable. Primarily used in on-line applications where the system can be de-pressurized or drained for sensor servicing. The Handrail Mounting Hardware is designed to attach to standard 2" handrails for mounting into open tanks and basins. It is a boom-like assembly that allows the sensor to be swung out of the process for servicing. Primarily used for aeration basins and open tanks. The optional Float-Ball Attachment for the handrail mounting hardware is designed to maintain submersion depth of sensors in applications that involve widely changing fluid levels. The float allows the mounting hardware to pivot. Primarily used in aeration basins where the level changes periodically by greater than 2 feet.
2. Can the sensor be mounted so it just hangs down into the process tank? BACK TO TOP
While the sensor is designed to be completely submerged, we recommend that some form of hardware be used to keep the sensor firmly secure in continuous measurement applications. The sensor may become damaged over time if it is allowed to bang into the sides of a tank.
3. Do I need a special hardware kit for panel mounting the Q45 transmitter?
The standard Q45 loop-powered transmitter can be panel mounted with no special hardware. Since the back of the enclosure is empty, it is removed and the front of the enclosure is surface mounted to the enclosure. A formed gasket is already attached to the enclosure front. For the relay and 115/230 VAC power supply versions, a special kit must be used to retain the entire enclosure in the panel. Various sized cut-out adapters are also available for retrofits.