Oil and Gas Has a Water Scarcity Problem. Your Cooling Tower Chemicals Are Making It Worse.

Some oil and gas facilities are now running their cooling towers at half the water cost. Here’s what they changed.

If you’re running cooling tower operations in oil and gas, you already know where your water is going. What’s harder to see is that the standard response to that problem – more chemicals to control fouling, more blowdown to manage TDS, more makeup water to replace what’s discharged – is actively making it worse.

Every chemical you add to stay stable raises the dissolved solids load that caps your cycles of concentration. The ceiling you keep hitting on water costs isn’t external pressure from the market. It’s your own treatment model working against you.

There’s a different operating model that oil and gas facilities are using to reduce water consumption, chemical dependency, and energy costs at the same time. Here’s what it looks like – and what it’s worth

Why Is Water Scarcity Now an Operational Issue in Oil & Gas?

Tracking water use and actually managing it are different things. Most oil and gas facilities are doing the former while the latter gets more expensive every year.

Municipal systems in many regions are under pressure from aging infrastructure, growing demand, and competing users. In some areas, they cannot reliably deliver the volumes large industrial operations depend on. At the same time, cost structures are shifting. Facilities are now navigating:

• Tiered pricing that penalizes higher usage
• Discharge fees tied to volume and total dissolved solids
• Surcharges and fines linked to non-compliance or overuse

Facilities are no longer managing just water. They are managing availability, cost, and regulatory pressure – all at once.

The facilities still treating water as a guaranteed utility are going to feel that shift in their operating budget before they feel it anywhere else.

The Loop Your Chemicals Are Creating

Cooling towers are often among the largest continuous water users on site. Yet they are rarely optimized. Most systems run at conservative cycles of concentration (CoC), rely on continuous blowdown, and depend heavily on chemical programs to stay stable.

Most oil and gas cooling systems run between 4 and 6 cycles of concentration. Operators know that increasing CoC would reduce water use. But every time they try, the system pushes back. Scale forms. Biofilm builds. Efficiency drops. The response is typically more chemistry and more blowdown.

This approach has been accepted for decades because water was inexpensive and available. That calculation has changed.

Why Adding More Chemicals Makes the Problem Worse

The more chemistry a system requires to stay stable, the more dissolved solids accumulate in the circulating water. That is where the constraint begins.

Total dissolved solids (TDS) rise as water concentrates in the system. Chemicals added to control scale, corrosion, and biological growth contribute directly to that TDS load. As TDS climbs, the water’s capacity to hold minerals in solution decreases. Minerals fall out of solution earlier – meaning scale forms at lower concentration levels than it otherwise would.

This is the mechanism that caps CoC. The system hits a ceiling not because of the source water itself, but because of what has accumulated inside it. To manage that, operators increase blowdown. Blowdown drops TDS but also drops cycles. To compensate, more chemistry is added. TDS rises again.

The result is a reinforcing loop:

1. More chemistry → higher TDS
2. Higher TDS → lower achievable CoC
3. Lower CoC → higher blowdown
4. Higher blowdown → more makeup water required
5. Repeat

The system stays stable. You just pay more every year to keep it that way and the ceiling on what you can achieve never moves.

Image source: Understanding Fouling – Medium

What Scale and Biofilm Fouling Is Actually Costing You

Biofilm and scale are commonly understood as water quality problems. Their impact on energy consumption is often underestimated.

What happens to heat transfer efficiency when surfaces foul?

Fouled heat transfer surfaces don’t just waste water; they drive up energy demand at the same time. You’re paying more to get less cooling output, while also managing the water costs that got you there. Industry data shows that just 1 mm of biofilm on heat exchanger surfaces can reduce heat transfer efficiency by 10 to 40 percent.

Scale has a similar effect. As minerals precipitate and deposit on heat transfer surfaces, they create additional thermal resistance. The system works harder – and uses more energy – to maintain the same cooling output.

The downstream effects compound:

• Energy demand increases to compensate for reduced heat transfer
• Water flow may increase to maintain target performance
• Chemical dosing increases to manage active fouling
• Blowdown increases to reduce mineral loading in the system

Image source: ASHRAE Systems and Equipment Handbook, 2000

Water, energy, and chemical costs aren’t moving independently. They’re all being driven by the same root condition – and that’s exactly what makes it fixable.

AOP: The Tool That Breaks the Loop

Most cooling water treatment programs are built around managing symptoms. Scale inhibitors, biocides, and corrosion inhibitors control what is already present in the system. AOP takes a different approach.

Advanced Oxidation Process (AOP) generates hydroxyl radicals that break down organic material in the circulating water. In a refinery cooling loop, this means targeting biofilm and organic loading before they accumulate on heat transfer surfaces.

When organic loading is reduced at the source, the system behaves differently:

• Biofilm does not establish and build on heat transfer surfaces
• Scale formation decreases because the biological matrix that traps minerals is disrupted
• Chemical demand drops because the conditions requiring heavy treatment are no longer present
• System stability improves without dependence on increasing chemical input

This is not about pushing the system harder. It is about removing the conditions that create instability in the first place.

How Does AOP Enable Higher Cycles of Concentration With Less Risk?

When biofilm and organic loading are controlled at the source, the primary drivers of fouling and scale are diminished. That stability allows the system to operate at higher CoC levels without the same risk of surface fouling or system upset.

Here’s what it looks like in a real system.

What does that look like in a real cooling system?

A 20,000 GPM cooling loop representative of a smaller refinery or a single loop within a larger operation moving from 4 to 8 cycles produces this:

• At 4 cycles of concentration:

• • • Blowdown: ~100 gallons per minute
    • Daily discharge: ~144,000 gallons

• At 8 cycles of concentration:

• • Blowdown: ~40–45 gallons per minute
  • Daily discharge: ~62,000 gallons

That is a reduction of approximately 82,000 gallons per day. Sustained across a full operating year, that adds up to roughly 30 million gallons saved. At a combined water and sewer cost of $5 per thousand gallons – a conservative baseline in many U.S. industrial markets, where rates are often higher – that represents approximately $150,000 in direct annual water savings.

That’s before reduced chemical costs, lower discharge fees, and energy savings from cleaner heat exchangers. The water number alone justifies the conversation. The rest is upside.

When One Variable Moves, They All Move

These three variables are not independent. They move together. This is why AOP isn’t just a water treatment decision – it’s an operational efficiency decision.

As heat transfer efficiency drops, the system requires more energy to maintain output. To compensate, water flow and blowdown often increase. To control the fouling behind that inefficiency, chemical input rises – which increases TDS and further limits CoC. The entire system tightens around a single constraint: surface fouling.

When that constraint is addressed, the relationship reverses:

• Cleaner surfaces → better heat transfer → lower energy demand
• Lower organic loading → less biofilm and scale → reduced chemical need
• Reduced chemical input → lower TDS → higher achievable CoC
• Higher CoC → less blowdown → lower total water consumption

In regions where water is already constrained, declining heat transfer efficiency directly increases exposure to tiered pricing, discharge fees, and regulatory risk. What appears to be a water treatment issue is actually driving broader operational and sustainability outcomes.

The Business Case and the ESG Case Are the Same Case

The facilities getting ahead of this aren’t choosing between operational performance and sustainability targets. They’re hitting both with the same lever.

The measurable outcomes of running a higher CoC with reduced fouling include:

• Lower water consumption: reduced blowdown means less makeup water is required
• Lower energy demand: cleaner heat transfer surfaces reduce the energy needed to maintain output
• Reduced chemical dependency: lower organic loading means less chemistry required to maintain stability
• Lower discharge volume: less blowdown means lower TDS in discharge and reduced associated fees
• Reduced regulatory exposure: lower usage and cleaner discharge reduce compliance risk

These outcomes connect directly to sustainability reporting under CDP Water Security and GRI 303. They also connect directly to operating costs. This is not a trade-off between sustainability and performance. It is the same outcome, expressed two different ways.

The Gap In Your Cooling Loop Could Cost You

Water is no longer something industrial operations can assume will always be there. Cost, availability, and regulatory pressure are converging, and they are arriving faster than most facilities anticipated.

Cooling towers sit at the center of that equation. They are among the largest water users on site. They are also among the most underoptimized systems in most facilities. The gap between where they currently run and where they could run represents real costs, real water, and real risk.

The facilities getting ahead of this aren’t necessarily the ones with the newest equipment. They’re the ones that stopped treating water as a guaranteed utility and changed the model they’re running inside their own cooling loop. That change is available to you right now.

The ceiling on your water costs isn’t the market. It isn’t regulations. It’s the treatment model you’re running right now. Calculate What It’s Worth For Your System »

 

Frequently Asked Questions

What are cycles of concentration in a cooling tower, and why do they matter?

Cycles of concentration measure how many times dissolved solids in makeup water have concentrated in the circulating water before blowdown occurs. CoC is where the water cost actually lives. Most oil and gas facilities are running at 4–6 cycles when their system could support 8–9 – if the treatment model wasn’t creating the ceiling. The gap between those numbers is roughly 30 million gallons a year on a mid-sized loop. Higher cycles mean less water is discharged and replaced. Lower cycles mean more frequent blowdown and higher total water consumption. Increasing CoC is one of the most direct ways to reduce water use in a cooling system.

Why can’t cooling towers simply run at higher cycles of concentration all the time?

Higher CoC increases the concentration of dissolved minerals and dissolved solids in the circulating water. As TDS rises, minerals fall out of solution more easily, forming scale on heat transfer surfaces. Biofilm also becomes harder to control at higher concentrations. Without addressing those root conditions, higher cycles increase fouling risk and system instability.

How does biofilm affect energy use in a cooling system?

Biofilm forms an insulating layer on heat transfer surfaces, reducing the efficiency of heat exchange. The system must work harder – and consume more energy – to maintain the same cooling output. Even thin biofilm layers have a measurable impact on thermal performance. Scale creates a similar effect through added thermal resistance.

What is Advanced Oxidation Process (AOP) in water treatment?

AOP is a treatment method that generates oxidants to break down organic material in water. In cooling systems, it reduces biofilm and organic loading before they accumulate on heat transfer surfaces. This reduces fouling, lowers chemical demand, and improves system stability – which enables higher cycles of concentration with less risk of scale or system upset.

How much water can a cooling tower save by increasing cycles of concentration?

The savings depend on system size and current operating cycles. As a representative example, a 20,000 GPM cooling tower moving from 4 to 8 cycles of concentration could reduce blowdown by approximately 82,000 gallons per day – roughly 30 million gallons per year. At a combined water and sewer cost of $5 per thousand gallons, that represents approximately $150,000 in direct annual savings, before accounting for reduced chemical or energy costs.