Industrial Water Treatment Systems: Design, Installation and Service

Industrial water treatment is the set of filtration, softening, purification, conditioning and wastewater systems that make raw water fit for each use in a plant, and make used water fit to discharge or reuse. Paul Industries designs, fabricates, installs, starts up and services those systems nationwide, from the raw water inlet to the sewer connection. This page is the overview: it explains each part of a plant’s water system briefly and links to the detailed page for each one.

What is industrial water treatment?

It is treatment matched to a use rather than to a single standard. A public water system treats water to one drinking water standard; a plant treats the same incoming supply to several specifications at once: soft enough not to scale a boiler, pure enough for a product or a final rinse, controlled enough not to corrode a cooling loop, and clean enough on the way out to meet a sewer or discharge permit. What is industrial water, in that sense? Any water a facility takes in or produces for a purpose other than drinking: process water, boiler feed, cooling water, washdown and cleaning water, and the wastewater all of them become. Each stream has a quality target, and the industrial water treatment process for that stream is the shortest chain of equipment that reaches the target reliably at the lowest operating cost.

Plants treat water for four reasons: to protect equipment from scale, corrosion and fouling; to meet a product or process specification; to meet the limits in a wastewater permit; and, more and more often, to recover water for reuse because supply or discharge is expensive or capped. Most plants have all four reasons at once, which is why the treatment train is designed as a system, not bought as a single piece of equipment.

What is process water?

Process water is water that touches the product or the process: ingredient water, rinse and wash water, dilution water, and water used to raise steam, cool equipment or carry material. The uses of water in industry fall into a handful of groups, and each group sets a different treatment target.

Process water treatment, then, is not one technology but a decision made stream by stream. One process water treatment system often feeds several of these uses: a softener and carbon filter supplying a utility header, with an RO unit downstream of the same pretreatment for the streams that need low dissolved solids. Designing the shared pretreatment once, for the combined flow, is almost always cheaper than giving each use its own. Industrial process water treatment also has to follow the process as it changes: a new product, a tighter rinse specification or a production increase can push a stream past what its equipment was sized for, so headers and pretreatment are best laid out with room to add a unit.

Water treatment process steps in an industrial plant

The steps follow the same order nearly everywhere: remove what can be strained or settled, remove what would damage the next step, remove dissolved minerals to the level the use requires, protect the water in storage, and treat what goes down the drain. Each stage protects the one after it, which is why a failure upstream, such as a carbon filter that stops removing chlorine, shows up downstream as ruined resin or membranes.

A water treatment process flow diagram, the drawing that shows every unit, its flows, its controls and its drains, is the first deliverable on any new system. It is where redundancy, bypasses, sample points and drain capacity are settled before anything is bought, and it becomes the basis for the piping and instrument drawings.

What is raw water treatment?

Raw water treatment is the first stage: conditioning the incoming supply, whether city water, well water or surface water, so it can feed everything downstream. City water usually needs chlorine or chloramine removal and some filtration. Well water often carries iron, manganese, hydrogen sulfide and high hardness. Surface water brings turbidity, organics and seasonal swings that may call for clarification ahead of filtration.

Hardness is usually the first number a plant looks at. The USGS classifies water as soft at 0 to 60 mg/L as calcium carbonate, moderately hard at 61 to 120, hard at 121 to 180 and very hard above 180, and one grain per gallon equals about 17.1 mg/L. Industrial hard water treatment is normally ion exchange softening ahead of boilers, cooling towers, kitchens, laundries and RO units, covered in detail on our water softener installation, service and repair page. Where RO follows, antiscalant dosing can sometimes replace the softener; the water analysis decides which.

Chlorine is the second. It protects the public supply but damages polyamide RO membranes and oxidizes softening resin, so it is removed with activated carbon or sodium bisulfite injection. Chloramine, used by many utilities, is slower to remove and is normally handled with catalytic carbon and longer contact time. Iron and manganese are oxidized and filtered on dedicated media, because they foul resin and membranes and stain product.

Industrial water filtration

Filtration removes particles by size, and the right filter depends on how small the particles are and how much of them there is. An industrial water filter can be a media bed that backwashes itself, a bag or cartridge that is replaced, or a membrane that is cleaned in place.

An industrial water filter system is sized on flow per square foot of filter area, not on pipe size: undersized media filters channel and pass solids, and undersized cartridge banks plug in days. Each industrial water filter housing should carry differential pressure gauges or transmitters, because the pressure drop is what tells operators when to change elements, and it should be rated for the line pressure and for any cleaning chemicals it will see. Specify each industrial water filter cartridge by micron rating, absolute or nominal, and by material, and keep a set of spares on site. A process water filter at a point of use, ahead of spray nozzles or a plate heat exchanger, protects one piece of equipment for far less than filtering the whole header finer than it needs. Housings, skids and elements are covered on our process filtration systems page.

Industrial water purification: RO, DI and EDI

Purification removes dissolved minerals, which no filter can touch. Reverse osmosis forces water through a semipermeable membrane and typically rejects about 95 to 99 percent of dissolved salts, sending them to drain in a concentrate stream. Deionization exchanges dissolved ions for hydrogen and hydroxide on cation and anion resins, which are regenerated with acid and caustic on site or swapped out as exchange tanks. Electrodeionization, EDI, polishes RO permeate with resin that an electric current regenerates continuously, with no acid or caustic. A typical industrial water purification system is pretreatment, then RO, then DI or EDI where the use needs lower conductivity than RO alone delivers.

Recovery rate, membrane cleaning, array staging and concentrate disposal decide what RO costs to run, and are covered on our commercial reverse osmosis systems page. Packaged units are described under RO skids and water treatment skids, and the two purification routes are compared in RO vs DI water.

High-purity water for pharmaceutical and laboratory use

Where water is itself a regulated ingredient, as with USP Purified Water and Water for Injection, purification is followed by a sanitized storage and distribution loop, continuous conductivity and total organic carbon monitoring, and validation. That work differs enough in materials, design and documentation to have its own page: high-purity water system installation. The plant-level point is that a high-purity system usually shares raw water pretreatment with the rest of the plant, so the two are best designed together, with the pretreatment sized for both.

Boiler feedwater and steam

A boiler concentrates whatever comes in with its feedwater. Hardness forms scale on tubes, dissolved oxygen pits the boiler and feedwater piping, and carbon dioxide released from alkalinity makes condensate corrosive. The usual treatment is softening for low and medium pressure boilers, RO or demineralization where pressure or steam purity requires it, a deaerator to strip oxygen and carbon dioxide, and chemical feed for oxygen scavenging and internal treatment. The U.S. Department of Energy notes that most boilers above 200 psig need dissolved oxygen at 5 parts per billion or less, which is the level a pressurized deaerator is built to approach. Feedwater limits tighten as pressure rises, as set out in the ASME consensus on feedwater and boiler water chemistry for industrial boilers. Equipment, deaerators and blowdown are covered on our boiler feedwater and deaerator page.

Cooling water

An open cooling tower evaporates water and leaves the minerals behind, so the recirculating water is held in range by blowdown, makeup pretreatment and chemical feed that control scale, corrosion and biological growth, and Legionella risk is managed under a water management program following ASHRAE 188. Closed loops, including chilled water and data center cooling loops, need corrosion inhibitor, filtration and periodic testing rather than blowdown. Cycles of concentration, blowdown calculations, side stream filtration and Legionella testing are covered on our cooling tower water treatment page, and data center loops on our data center water treatment page.

Industrial wastewater treatment and reuse

What is industrial wastewater? It is everything the plant sends to drain: process rinses, spent cleaning solutions, cooling tower blowdown, softener and filter backwash, RO concentrate and product losses. The treatment it needs is set by where it goes. A plant discharging to a municipal sewer is an industrial user under the EPA National Pretreatment Program, 40 CFR Part 403, and must meet the general prohibitions, any categorical pretreatment standards for its industry, and the local limits set by the treatment works it discharges to. A plant discharging directly to a river or stream needs an NPDES permit under the Clean Water Act.

Process wastewater treatment for sewer discharge is usually pretreatment: screening, equalization to even out flow and strength, pH neutralization, removal of fats, oils and solids, and sometimes biological treatment to cut BOD and sewer surcharges. Reuse goes further. A tertiary water treatment process, typically filtration or ultrafiltration followed by RO and disinfection, can return treated wastewater to cooling tower makeup, washdown or boiler pretreatment, cutting both purchased water and discharge volume. Details are on our process wastewater and effluent and food plant wastewater pretreatment pages.

Industrial water treatment methods compared

Each method removes a specific class of contaminant and leaves the rest, so a treatment train is built by stacking methods until every contaminant that matters is covered.

Industrial UV water treatment illustrates the rule behind the table: UV inactivates organisms at the moment water passes the lamp but leaves no residual, so it protects a storage loop or a point of use, not a whole distribution system on its own.

How to choose an industrial water treatment system

Start from the water analysis and the quality each use requires, not from equipment. The decision comes down to five inputs:

• A full raw water analysis, with several samples across seasons for surface or blended supplies: hardness, alkalinity, total dissolved solids, silica, iron, manganese, chlorine or chloramine, organics, turbidity, pH and temperature.
• A numeric quality target for each use, written down and agreed with the people who own the product or the boiler.
• Flow: average, peak and daily total, so storage can cover peaks rather than every unit being oversized.
• Redundancy: duplex or N+1 equipment wherever losing the water system would stop production.
• Operating cost: salt, chemicals, membrane and resin replacement, power, and the cost of water sent to drain.

The same logic applies at smaller scale. A commercial water treatment system for a hospital, hotel, campus or food service operation usually means softening, carbon and filtration on the domestic and kitchen supplies. A commercial water filtration system for that kind of building is selected from the same analysis with smaller equipment, and commercial water purification systems such as small RO units serve laboratories, beverage and ice equipment, and humidification. We size and lay out these systems through our process engineering and design group.

Industrial water treatment equipment

The core equipment in most plants is a short list: raw water break tanks and booster pumps, strainers and media filters, carbon filters, softeners, RO units, DI or EDI polishers, UV units, storage tanks with vent filters, deaerators, chemical feed skids with metering pumps and day tanks, and the controls, analyzers and flow meters that tie them together. Interconnecting piping, valves and instruments are as much a part of the system as the units, and they are where most field problems start: the wrong materials, missing sample points, drains that cannot take a backwash flow.

Water treatment process equipment is delivered either as packaged skids, built and tested in a shop and set on a pad, or field-erected for larger flows. A small process water treatment plant for one production line is often a single skid; a full industrial water treatment plant serving a campus is a building with several trains, storage, and its own control room. Industrial water treatment chemicals, the antiscalants, inhibitors, biocides and oxygen scavengers, come from the plant’s chemical supplier; we do not sell chemicals as a supply program, but we install and service the feed equipment, controllers and injection points that dose them accurately.

Industrial water treatment services: design to long-term service

Our work covers the whole life of a system. On new projects that means water analysis review, process design, equipment selection, shop fabrication of skids and piping, installation, tie-ins during a shutdown, hydrotesting, disinfection, start-up and operator training. On existing systems it means troubleshooting, performance testing, membrane and resin replacement, controls upgrades, repairs and scheduled maintenance. Industrial water systems run around the clock, so we set up maintenance under service contracts with logged visits and readings, and plants in regulated industries can add commissioning and qualification through validation and commissioning.

Industries we serve

Food and beverage plants need consistent ingredient water, soft water for CIP and boilers, and pretreatment for high-strength wastewater. Pharmaceutical and biotech plants need compendial water plus all the utility water around it. Data centers need cooling tower makeup treatment and clean closed loops. Oil and gas facilities handle produced water, boiler feed and cooling water at scale; see our oil and gas page. General manufacturing needs rinse water, boiler feed and cooling water, and increasingly reuse to control water and sewer costs.

Choosing among water treatment companies

They fall into three groups, and most projects need more than one. Equipment manufacturers build softeners, RO units and filters. Chemical service companies supply and test treatment chemicals. Contractors design, build, install and maintain the system as a whole and coordinate the other two. Industrial water treatment contractors are the right lead when the job involves piping, tie-ins, shutdown work and several kinds of equipment, which describes most real projects. Many commercial water treatment companies serve hotels, offices and hospitals more than plants, and center on a boiler and cooling tower chemical program with packaged softeners and filters; a production plant usually needs the contractor role as well.

When comparing an industrial water treatment company, or a commercial water treatment company for a smaller building, ask who will be on site for start-up and who answers the phone at two in the morning when a softener stops regenerating. Ask for a review of your water analysis before a price, not after, and ask what the system will cost to operate per thousand gallons, not only what it costs to buy. Good industrial water treatment solutions are the ones operators can actually run, with clear alarms, accessible sample points and room to maintain every unit.

What Paul Industries does

Paul Industries designs, fabricates, installs, starts up and services plant water systems nationwide: raw water filtration, softening, carbon and iron removal, RO, DI and EDI, high-purity water generation and distribution, boiler feedwater equipment and deaerators, cooling tower water treatment equipment, chemical feed systems, storage tanks, wastewater pretreatment, and all the interconnecting piping. We work in operating plants, during shutdowns and on new construction. Request a quote with your water analysis and a list of the uses you need to supply.

Standards referenced: EPA 40 CFR Part 403 · Clean Water Act NPDES · ASHRAE 188 · USP Purified Water monograph · ASME Consensus on Operating Practices for the Control of Feedwater and Boiler Water Chemistry · ASME B31.3 · NSF/ANSI 61

Frequently asked questions

Why is water treatment important for industrial plants?

Untreated water scales heat transfer surfaces, corrodes piping and boilers, fouls membranes and can contaminate product, and untreated wastewater can breach a discharge permit. A thin layer of scale on a heat exchanger or boiler tube raises fuel and power use long before anything fails, so treatment usually pays for itself in energy, equipment life and avoided downtime.

How much does an industrial water treatment system cost?

It ranges from the price of a single filter or softener to a major capital project for a multi-train plant with RO, polishing, storage and controls, so a meaningful number needs the water analysis and flows. The drivers are flow, the raw water analysis, the purity required, redundancy, whether equipment is skid-mounted or field-erected, and installation conditions. Compare options on operating cost per thousand gallons as well as purchase price, because salt, chemicals, membranes and drain water often exceed the capital cost over the system's life.

How do industrial water filters work?

Media filters trap particles in a deep bed of graded sand, anthracite and garnet, then reverse flow to backwash the trapped solids to drain. Cartridge and bag filters strain water through a rated element that is replaced when the pressure drop rises. Carbon filters adsorb chlorine and organics onto the surface of the carbon rather than straining them. Membrane filters such as ultrafiltration sieve particles and bacteria at a fixed pore size and are cleaned by backwash and chemicals.

Is process water safe to drink?

Not unless it is specifically treated and maintained as potable water. Process water may be softened, deionized, chemically treated, recycled or stored in ways that make it unsuitable for drinking, and in many plants it is not protected against backflow from equipment. Drinking water outlets should be fed from the potable system, separated from process water by approved backflow prevention.

What industries use water filtration?

Nearly all of them: food and beverage, dairy, breweries, pharmaceutical and biotech, cosmetics, power generation, oil and gas, chemicals, metal finishing, electronics, pulp and paper, data centers, hospitals and commercial buildings. The difference between industries is not whether they filter but what fineness and what level of documentation they need.

How is industrial waste water handled?

It is collected, characterized by sampling, and then pretreated to meet the receiving sewer's limits or treated further for direct discharge or reuse. Typical steps are screening, equalization, pH adjustment, fat, oil and solids removal and, where the load is high, biological treatment. Sludge and residuals from those steps are dewatered and hauled for disposal, and the discharge is monitored and reported under the permit.

What is industrial water management?

It is the plant-wide practice of measuring where water comes in, where it goes and what it costs, then reducing use and discharge. In practice that means metering major users, raising cooling tower cycles, recovering condensate, reusing rinse water and RO concentrate where quality allows, and fixing leaks, all of which reduce both water purchase and sewer charges.

What is the difference between water filtration and water purification?

Filtration removes particles: sediment, rust, some organisms and anything else that exists as a solid. Purification removes dissolved substances such as salts, hardness and silica, which pass straight through filters. Reverse osmosis, deionization and distillation purify; media, cartridge and bag filters only filter, which is why purification equipment always sits downstream of filtration.

What is makeup water?

Makeup water is the water added to a boiler, cooling tower or closed loop to replace what is lost to evaporation, blowdown, steam use or leaks. Its quality matters more than the quality of the water already in the system, because every impurity in makeup water is concentrated in the system over time.

Can you work alongside our existing water treatment chemical vendor?

Yes. Paul Industries installs and services the treatment equipment, feed systems, injection points, controllers and sample connections, and coordinates with the plant's chemical supplier on dose points, monitoring and the testing schedule. We do not supply chemicals ourselves, so the program and the hardware stay cleanly separated.

What water test results do we need before choosing equipment?

At minimum hardness, alkalinity, total dissolved solids or conductivity, pH, iron, manganese, silica, chlorine or chloramine, turbidity and temperature, and for RO feed also sulfate, barium, strontium and organics. Well and surface supplies should be sampled more than once, because a single sample can miss seasonal changes that decide whether a system copes or fails.

Does a plant need a permit to discharge treated water?

Usually yes. Discharges to a municipal sewer are governed by the sewer authority's pretreatment rules and often an industrial user permit; direct discharges to surface water require an NPDES permit. Even clean streams such as cooling tower blowdown and RO concentrate are covered, so check with the authority before changing what goes to drain.

Can treated wastewater be reused in the plant?

Often, for uses that do not touch product: cooling tower makeup, washdown, boiler pretreatment feed and irrigation. Reuse needs filtration, frequently membranes, and disinfection, plus a monitoring plan so quality is proven before it enters the reuse system. Food and pharmaceutical plants must also confirm what their regulators and quality systems allow.

What causes most water treatment system failures?

Changes in raw water that the design did not anticipate, pretreatment failures that pass chlorine, iron or solids to resin and membranes, and maintenance that lapses after start-up. Logging pressures, flows and conductivity every shift catches most problems weeks before they become outages.

How often should water treatment equipment be serviced?

Operators should log key readings daily. Filters, softeners and RO units typically need inspection and calibration monthly or quarterly, media and resin checks annually, and membrane cleaning when normalized performance shows it is due rather than on a fixed calendar. Systems feeding boilers or production deserve a written schedule that names who does each task.

Do you service systems another company installed?

Yes. We troubleshoot, repair, upgrade and maintain water treatment systems regardless of who built them, and we start with a site survey and the original drawings and data where they exist.

Related: High-Purity Water System Installation (USP, WFI, RO/DI) · Commercial Reverse Osmosis Systems, Skids and Equipment · Process Wastewater, Effluent & Chemical Sanitization · Cooling Tower Water Treatment · Oil And Gas · Data Centers · Request a quote · Deaerator Installation, Inspection and Service