Fluff and Reverse Osmosis

How is water used at a manufacturing facility?

You might be surprised to learn just how much water is consumed at a manufacturing facility. From diluting raw materials to cooling down reactors, water is critical to the successful operation of the facility. There are many ways in which water is used including:

  1. Diluting incoming raw materials such as concentrated chemicals
  2. Dissolving powders to make large batches of solvent or cell media
  3. Cooling down equipment such as reactors (as chilled water)
  4. Preventing pipelines from freezing (as steam)
  5. Providing hydrostatic pressure for sealing systems in large pumps and reactors

Real quick, the fancy word “hydrostatic pressure” just means the pressure being exerted is coming from the water, and not from the equipment.

How does the water get there?

Water is typically sent to a manufacturing facility using large pipes from neighboring cities and towns. Sometimes, the water is taken directly from a river or lake nearby. The water quality can vary considerably depending on its source.

The quality of the water depends on where the water is being used at the facility. For example, the water used to prepare drug solutions at pharmaceutical plants needs to be of the highest quality, since it is meant for human use. Figure 1 below shows a liquid pharmaceutical production line.

Pharmaceutical Production Line
Figure 1: Pharmaceutical Production Line

On the other hand, the water used to cool down a chemical reactor does not need to be as clean since that water never enters the process. In this case, the water is sent to a jacket that wraps around the outside of the reactor to provide cooling. In Figure 2 below, the reactor is shown with “orange” contents. The jacket wraps around the outside of the reactor and is shown with “blue” cooling water.

 Reactor showing difference between contents and reactor jacket
Figure 2: Reactor showing difference between the contents inside a reactor and the jacket that wraps around the outside of a reactor

Facilities use different ways to clean up or purify the incoming water. One of the most commonly used ways is reverse osmosis. But before we get into reverse osmosis, let’s take a step back and discuss osmosis first.


Have you ever made Kool-aid from the packets and watched the water turn red, or pink or whatever tasty flavor you bought? Have you ever made hot chocolate and watched the milk turn into brown frothy goodness? Osmosis is the force behind these delicious drinks.

Osmosis is the process by which very small molecules move from an area where there are lots of them (high concentration), to an area where there are not so many of them (low concentration). The process of osmosis occurs across a thin platform with many tiny holes, called a semi-permeable membrane. The holes only allow molecules small enough to fit to pass through.

In Figure 3 below, the molecules are indicated by the blue circles, and the membrane by the red dashed line. The very fine dots is the “water”that the molecules are in. The first box in Figure 3 shows the (blue) molecules to the left before osmosis has taken place. Over time, the molecules move over to the right by crossing the (red) membrane, as shown in the second box. This is the process of osmosis. In the third box, there are just as many molecules on the left side as there are on the right side. Osmosis is complete.

Figure 3: Osmosis

Reverse Osmosis

As the name suggests, reverse osmosis switches up what’s moving and in which direction.

In reverse osmosis, the molecules are forced to move across the membrane in one direction using external pressure. Without this external pressure, the molecules would remain where they are.

In Figure 4 below, we start with all the (blue) molecules evenly spaced on the left and the right side as shown in the first box. Reverse osmosis begins in the second box as the (blue) molecules are forced to cross the (red) membrane. In the third box, reverse osmosis is complete; there are now more (blue) molecules on the left side than on the right side.

Reverse Osmosis
Figure 4: Reverse Osmosis

Manufacturing facilities use reverse osmosis to forcibly remove unwanted molecules from their incoming water supply. These unwanted molecules are typically chemicals that cause water hardness. You know that white crusty stuff that accumulates on your glass shower door? That’s water hardness. Reverse osmosis removes this hardness from the water supply.

Was anybody taking notes?

I remember working on the design and installation of a brand new reverse osmosis unit at a manufacturing facility. The facility had relied on well water for decades as their primary source of water. The water was then purified using an ion-exchange chromatography skid. This skid was as complicated as it sounds. The chemicals used to maintain the skid were becoming very expensive. I was tasked with finding a more economical solution.

After considering several options, we decided on a new reverse osmosis skid to purify our incoming water. I worked with a vendor to size the new skid. The new skid had to be large enough to handle all the water that the facility used daily.

Once the design was complete, the vendor came to site to help us with installation. It took a few days to get everything set up, but once it was said and done, the reverse osmosis unit worked like a charm.

On the last day the vendor was on site, one of the operators looked around and said, “Was anybody taking notes?”


I quickly raised my hand and said “I was!”.

The look of collective relief on their faces was priceless!

Although this was very early on in my career as a Process Engineer, I had already earned a reputation as an impeccable note taker. I wrote everything down – everything! I didn’t know what I didn’t know, so I left nothing to chance and just took notes as I continued to learn the process. It was to the point where some of the newer operators would ask for my note book to help them train for the operator knowledge tests. I kid you not! My notes were that good.

I got to work right away compiling my notes on the new reverse osmosis unit. I decided to first make a short PowerPoint presentation. This would be a quick reference guide to help the operators better understand the fundamentals of the reverse osmosis process.

Then, I created a brand new internal SOP (Standard Operating Procedure) that captured the specific checks that the operators had to perform. After all, it was a brand new piece of equipment, and I didn’t want it to fail just because nobody knew how to operate it. I leveraged a lot of material from the vendor, but made sure to write the SOP in the voice and tone of other internal documents at the site. I didn’t want to lose the operators if this new document was vastly different from others they had already been trained on.

Fluff vs Effective Documentation

The success of this newly installed reverse osmosis unit was due to proper design and proper documentation. In my opinion, design and documentation go hand in hand. Good design involves recording the “why” behind the design as much as the “what” and the “how”.

An engineering mentor once told me, that years from now, someone should be able to go through your design documents and clearly understand what was done. How many times have you been in a situation where that deep equipment knowledge left when the individual who had it left?

Developing and maintaining good records on every piece of equipment at your manufacturing facility is essential.

So what makes a document effective? The document needs to be:

  • Concise
  • Clear
  • Use labels
  • Use lists

Everything else is just fluff.

Effective documentation filters out the fluff, allowing you to engage with your target audience on a much deeper level. For a better visual of what fluff vs effective documentation looks like, see Figure 5 below.

Fluff vs Effective Documentation
Figure 5: Fluff vs Effective Documentation

Reach out today to start your journey from fluff to effective documentation.

This article is also published on Linkedin.

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