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Khan Associates supplies online sensors, process analyzers, controllers, flow measurement instruments and UV disinfection systems to industrial plants and utilities across Pakistan. We have been importing and supporting instrumentation here since 1994.
Online instrumentation answers a question a laboratory cannot: what is happening right now. A grab sample tells you what the water was doing when someone filled the bottle. A continuous analyzer tells you what it is doing at three in the morning when nobody is on the sample line, which is when most process excursions actually happen. That difference is the whole commercial case for online measurement.
We are an authorized distributor, not a reseller of grey-market instruments. Equipment arrives through the official channel with manufacturer warranty, and is supported with sizing, application guidance and after-sales service from Lahore and Karachi.
Everything on this page comes from three manufacturers, and all three are operating companies within Veralto’s Water Quality segment. That is worth knowing, because it means the analysis, the flow measurement and the disinfection on your site can come from one engineering family and one local partner rather than three unrelated vendors with three service routes.
The rest of this page explains what each measurement is for, and where it belongs in a plant.
These three words get used interchangeably in enquiries, and the confusion leads to incomplete purchase orders. They are different devices with different costs and different maintenance burdens.
A sensor or probe measures a property directly and continuously by physical or electrochemical means. pH, ORP, conductivity, dissolved oxygen and turbidity are all sensor measurements. Sensors are comparatively simple, need no reagents, and their running cost is calibration and eventual probe replacement.
An analyzer performs an actual analysis on a sample stream, usually a wet-chemistry method with reagents, on a repeating cycle. Chlorine, ammonium, nitrate, phosphate, silica, sodium and TOC are typically analyzer measurements. An analyzer gives you a result every few minutes rather than continuously, and it carries an ongoing reagent and consumable cost that belongs in the budget from day one.
A controller, such as the HACH sc series of digital controllers, is the head unit. It powers the sensors, handles digital communication, displays and logs readings, manages calibration and diagnostics, and drives outputs, relays and alarms. One controller commonly serves several sensors, which is why the number of controllers you need is not the same as the number of parameters you are measuring.
Getting this right at quotation stage matters. A parameter list alone is not a specification: we need to know whether you are buying probes onto an existing controller, a complete panel, or an analyzer with its reagent programme.
These are the workhorse sensor measurements, present on almost every treatment plant and utility system.
pH and ORPpH governs nearly every chemical reaction in water treatment, from coagulation efficiency to corrosion tendency to whether a biological system stays healthy. ORP, the oxidation-reduction potential, indicates the oxidising or reducing character of the water and is widely used as a fast proxy for disinfection and for dechlorination control. Both are continuous sensor measurements, normally run into a shared controller. | ConductivityConductivity tracks total dissolved ionic content. In practice it is the fastest, cheapest indicator of a change somewhere in the system: RO permeate quality and membrane integrity, boiler blowdown control, cooling tower cycles of concentration, demineralisation plant exhaustion and condensate contamination are all monitored on conductivity. |
Dissolved OxygenIn an activated sludge aeration basin, dissolved oxygen is both a process requirement and the largest single power cost on the plant. Blowers typically dominate a treatment works’ electricity bill, and controlling them on a live DO reading rather than running them flat out is one of the clearest returns available from online instrumentation. Dissolved oxygen is also monitored in boiler feedwater, where it drives corrosion, and in aquaculture, where it decides stock survival. | Turbidity and Total Suspended SolidsTurbidity measures how much light suspended particles scatter, and is the standard indicator of clarification and filtration performance in drinking water production. Total suspended solids measurement quantifies the solids concentration itself and is used in wastewater on mixed liquor, return sludge and final effluent. The two are related but not the same measurement, and the right one depends on whether you need a water-clarity indicator or a solids concentration. |
Total Organic CarbonTOC measures organic carbon content, used where organics matter directly: pharmaceutical purified water systems, high-purity industrial water, RO feed monitoring, and as an early indicator of organic contamination in a process stream. |
Disinfection is the one part of water treatment where under-dosing is a public health failure and over-dosing creates by-products and cost. It is therefore measured continuously almost everywhere it is practised.
Free and total chlorine residual analysis, including the HACH CL17sc continuous chlorine analyzer, is the standard control measurement at drinking water plants, in distribution networks and in bottled water and beverage production. Chlorine dioxide is monitored separately because it is a different oxidant with a different residual behaviour and is used where chlorine’s by-product formation or taste impact is a problem.
Where chloramination is used to hold a stable residual across a large distribution network, both the chlorine-to-ammonia ratio and the monochloramine residual have to be monitored, because an imbalance causes nitrification in the network. Ammonium measurement in wastewater serves a different purpose entirely: it indicates nitrification performance in the biological stage and is a routine discharge parameter.
Ozone is a strong oxidant used for disinfection, colour and taste and odour removal. It is monitored both as a dissolved residual in the water and, for safety, in the ambient air around generation equipment.
These are reagent-based analyzers rather than probes, and they are how a treatment plant runs its biological and chemical stages on real data.
Ammonium, nitrate and phosphate analyzers monitor nutrient removal in wastewater treatment, supporting aeration control, carbon dosing and phosphorus precipitation. Running these on live analyzer data rather than daily grab samples is what allows a plant to cut chemical and energy consumption without risking its discharge numbers.
Fluoride is monitored where fluoridation is practised or where natural fluoride in groundwater needs to be tracked. Hardness monitoring is primarily a protection measurement: it is placed on softener outlets and boiler makeup lines, where hardness breakthrough means the resin has exhausted and scale is about to start forming somewhere expensive.
Power plants and high-pressure steam systems monitor a specific set of parameters, because the consequences of getting cycle chemistry wrong are measured in turbine and boiler damage rather than in a compliance report.
Silica is monitored because it carries over with steam and deposits on turbine blades, where it is extremely difficult to remove. Sodium is monitored at parts-per-billion level as the most sensitive early indicator of condenser leakage or ion exchange breakthrough. Oxygen scavenger monitoring tracks the residual of the reducing agent dosed to remove dissolved oxygen from feedwater, confirming that oxygen corrosion protection is actually present rather than assumed. All three are analyzer measurements, and all three are cheap compared with what they protect.
Dissolved and headspace gas measurement serves two very different groups. In beverage production, carbon dioxide and oxygen are product quality parameters: carbonation level and dissolved oxygen ingress both affect shelf life and taste. In power generation, hydrogen monitoring relates to generator cooling and to cycle chemistry, and nitrogen measurement appears in blanketing and inerting applications.
Sludge level measurement tracks the sludge blanket in a clarifier or thickener. It is one of the most practically useful measurements on a treatment plant, because a rising blanket is an early warning of carry-over into the final effluent, and a blanket allowed to drop too far means the sludge withdrawal pump is drawing thin sludge and sending water to the dewatering equipment.
Oil in water monitoring is used on discharge and process streams at refineries, workshops, power stations and any site where hydrocarbon contamination is credible. Particle counting is used in drinking water treatment as a more sensitive indicator of filter performance than turbidity alone, since it counts and sizes particles rather than measuring bulk light scatter.
Flow deserves separate treatment from water quality, because the selection logic is entirely different. A water quality instrument is chosen by parameter. A flow meter is chosen by what the pipe and the fluid will allow.
Electromagnetic and Insertion Magnetic MetersElectromagnetic meters measure conductive liquids with no moving parts and no obstruction to flow, which makes them the default choice for water and wastewater. Full-bore magnetic meters such as the McCrometer Ultra Mag and Dura Mag serve municipal water and wastewater duty. The FPI Mag full profile insertion meter deserves specific mention, because it solves a problem most Pakistani utilities and plants actually have. It installs through a hot tap, on a live line, without shutting down supply, dewatering the pipe or cutting and welding. For retrofitting measurement onto an existing distribution network or a plant line that cannot be taken out of service, that is often the difference between a measurement project happening and not happening. Note that electromagnetic technology requires a conductive liquid, so it is not applicable to hydrocarbons, gas or steam. | Differential Pressure Flow, Including SteamDifferential pressure meters infer flow from the pressure drop across a restriction, and are the established route for gas and steam where magnetic meters cannot be used. The McCrometer V-Cone conditions the flow profile within the meter body, so it holds accuracy where upstream straight pipe run is short. That matters in crowded plant rooms, metering skids and wellheads, where the textbook straight-run requirement simply does not exist. The ExactSteam configuration provides steam energy metering, which is directly relevant to any mill or plant trying to allocate steam cost by department. |
Propeller and Irrigation FlowMechanical propeller meters such as the McPropeller remain the practical choice for high-volume water measurement and irrigation duty, including dirty water where other technologies struggle. Combined with telemetry, they support volumetric water accounting on canal outlets, tubewells and pressurised irrigation schemes. | Open Channel and Ultrasonic FlowOpen channel flow measurement applies where water is not in a pressurised pipe: treatment plant channels, effluent discharge points and irrigation channels. It is typically derived from a level measurement over a calibrated flume or weir, or from a combined area-velocity sensor in the channel itself. Ultrasonic measurement is used both as the level element in open channel systems and, in clamp-on form, for non-invasive measurement on closed pipes. Because open channel and ultrasonic installations vary so much with the civil works and the channel profile, these are specified case by case. Send us the channel or pipe details and we will confirm what we can supply for that specific installation. |
Ultraviolet disinfection inactivates microorganisms physically. UV light at germicidal wavelengths damages the nucleic acid of bacteria, viruses and protozoa so they cannot reproduce. Nothing is added to the water, and no disinfection by-products are formed.
This section exists because UV is frequently oversold, and a system bought on the wrong expectation is an expensive disappointment.
UV does inactivate bacteria, viruses and chlorine-resistant protozoa including Cryptosporidium and Giardia, which chemical disinfection handles poorly. It does so without chemical storage, chemical handling risk or by-product formation, and without altering taste or odour.
UV does not remove dissolved chemicals, salts, hardness, suspended solids, turbidity or organic load. It is a disinfection step, not a treatment process, and it does not replace clarification, filtration, softening or RO. Two practical consequences follow. First, UV performance depends on the water’s UV transmittance: high turbidity or colour absorbs and scatters the light, so upstream treatment has to deliver water the UV system can actually penetrate. Second, UV leaves no residual, so it cannot protect water travelling through a distribution network after the point of treatment. Where a residual is required, UV and a chemical residual are used together rather than as alternatives.
Correct sizing is everything, and it rests on three inputs: flow rate, UV transmittance, and the log reduction the application requires. Genuine lamps and quartz sleeves matter for the same reason, because a system only delivers its validated dose if it is maintained to specification.
Instruments earn their place by changing a decision. These are the points where continuous measurement typically pays for itself.
Online measurement works alongside laboratory analysis rather than replacing it. Grab sampling and reference methods remain how instruments are validated and how reported results are confirmed. We supply both sides: see our laboratory supplies and instruments range for benchtop analysis and reagents.
Most instrumentation disappointments trace back to a specification gap rather than a faulty instrument. These are the details that determine whether the right device is quoted.
For UV systems the inputs are different again: flow rate, UV transmittance and required log reduction. For flow meters: line size, fluid, and installed straight run.
Instruments and treatment chemistry are usually bought by the same team. Our water treatment chemicals range covers the coagulants, antiscalants, inhibitors and biocides these instruments help you control and dose correctly.
A parameter list is a starting point, not a specification. The more of the following you can include, the more accurate the quotation:
Our team will respond with a recommendation and a formal quotation, including technical documentation, within one working day.
Instruments installed permanently on a process stream that measure continuously or on a repeating cycle, rather than analysing a sample taken to a laboratory. They give live readings that can drive alarms, logged records and automatic control, so operators respond to changes as they happen instead of after the next grab sample is analysed.
A sensor measures a property directly and continuously, such as pH, conductivity, dissolved oxygen or turbidity. An analyzer runs an actual analysis on a sample, usually with reagents on a repeating cycle, for parameters like chlorine, ammonium, phosphate or silica. A controller is the head unit that powers the sensors, displays and logs readings, manages calibration and drives outputs and alarms. One controller often serves several sensors.
Because aeration blowers are usually the largest single power consumer on the plant. Controlling them on a live dissolved oxygen reading, rather than running them continuously at a fixed output, reduces energy consumption while keeping the biological process healthy. It is one of the clearest returns available from online instrumentation.
Conductivity indicates total dissolved ionic content and is the fastest general indicator that something in a water system has changed. It is used for RO permeate quality and membrane integrity, boiler blowdown control, cooling tower cycles of concentration, demineralisation plant exhaustion and condensate contamination.
Turbidity measures how much light suspended particles scatter, and is the standard clarity indicator for drinking water clarification and filtration. TSS measurement quantifies the actual concentration of suspended solids and is used in wastewater on mixed liquor, return sludge and final effluent. They are related but they answer different questions.
Silica carries over with steam and deposits on turbine blades, where removal is difficult and expensive. Sodium is monitored at very low concentrations as the earliest indicator of condenser leakage or ion exchange breakthrough. Both are cheap measurements relative to the equipment they protect.
It tracks the sludge blanket in a clarifier or thickener. A rising blanket warns of solids carry-over into the final effluent before it shows up in the discharge sample, and a blanket that has dropped too low means the withdrawal pump is sending thin sludge to the dewatering equipment.
Electromagnetic meters generate a signal from a conductive liquid moving through a magnetic field, so they require a conductive fluid and are unsuitable for hydrocarbons, gas or steam. They have no moving parts and no flow obstruction, which makes them the default for water and wastewater. Ultrasonic meters use sound transit time or reflection and can be clamped onto the outside of a pipe for non-invasive measurement, and are also used as the level element in open channel systems.
Yes, with an insertion meter. The McCrometer FPI Mag is designed for hot-tap installation on a live line, without dewatering, cutting or welding, which is why it is used for retrofitting measurement onto existing municipal distribution networks and plant lines that cannot be taken out of service.
Flow measurement where water is not in a pressurised pipe, such as a treatment plant channel, effluent discharge point or irrigation channel. It is usually derived from a level measurement over a calibrated flume or weir, or from an area-velocity sensor in the channel. Because it depends heavily on the civil structure, each installation is specified individually.
Because it conditions the flow profile inside the meter body rather than relying on long upstream straight pipe to do it. That makes it suitable for compact metering skids, wellheads and crowded plant piping where conventional differential pressure meters cannot meet their straight-run requirement.
UV inactivates microorganisms physically, including chlorine-resistant Cryptosporidium and Giardia, without adding chemicals, forming disinfection by-products or affecting taste and odour. Chlorine leaves a residual that continues protecting water downstream, which UV cannot do. They are often used together rather than as alternatives, with UV as the primary barrier and a chemical residual for the distribution network.
No. UV is a disinfection step, not a treatment process. It does not remove dissolved chemicals, salts, hardness, suspended solids, turbidity or organic load, and it leaves no residual protection downstream. It also depends on the water’s UV transmittance, so upstream clarification and filtration must deliver water the UV light can penetrate.
On three inputs: the flow rate, the UV transmittance of the water, and the log reduction the application requires. Maintaining the validated dose over time also depends on using genuine lamps and quartz sleeves and keeping to the maintenance regime.
Yes. We supply industrial plants and utilities nationwide from our Lahore corporate office and Karachi office, with sizing, application support and after-sales service from both locations.
Send us your parameters, sample details and installation conditions, and our team will recommend the right instruments with a formal quotation and technical documentation within one working day.
Lahore Corporate Office
184-S, Quaid-e-Azam Industrial Estate, Kot Lakhpat, Lahore, Pakistan
+92-42-35146680-83
Karachi Office
908-909, 9th Floor, Portway Trade Centre, Plot 189/A, S.M.C.H.S., Main Shahrah-e-Faisal, Karachi, Pakistan
+92-21-34540251-52
khi@khanassociates.net
Email info@khanassociates.net or message us on WhatsApp at +92 301 4168242, 9:00 am to 5:00 pm.