What’s (Water) on Your Mind?

from AWT Fall 2022 Analyst

by Association of Water Technologies

Business Notes

What’s in Your Toolbox?

Compiled by James McDonald, Chem-Aqua

Note: The following discussions come from the Industrial Water Treatment interest group on LinkedIn.

Question of the Week What's in your toolbox or test kit that some people may not think about including in theirs?

Steve: A thumb drive. To extract data from a controller that is not connected to the internet.

Dennis: Most don't have a magnetic stirrer.

Steve: Camphor. I have always used camphor shavings to look for oil in condensate, boiler water or leaking heat exchangers. In clean water, camphor shavings will actually spin on the surface, with the slightest amount of oil it will stop spinning immediately. It is fun to show a client a beaker with clean water, put shavings in and see them dance around, then put your finger in (skin oil) and watch the shavings stop. I have identified many, many process leaks this way.

Seth: Scratch paper so you can map out systems at customer sites. The more I knew about an individual system, the easier it was to service it.

Jeff: A nice, bright head lamp. I have one on my hard hat and it really helps in those luxurious boiler rooms we all spend our time in. Also, may be obvious, but tubing, foot valves, weights and injection quills. Nothing kills productivity more than having to stop back at a customer's facility to fix a leaking pump. Much more efficient to fix while onsite the first time and drive value to your customer by being able to react quickly. Allen: A 47-mm filter holder and luer syringe "pump" with test filter circles from 0.45 to 30-micrometers (µm) to test for filtration requirement. Also carry an ultrafiltration (UF) test module and deionized (DI) water dispenser to create sample dilutions.

Todd: I thought that everyone was only given a vice grips, strap wrench, duct tape and an extra-long Philips screwdriver for tools to use. Jokes aside, I always carried a crossover cable for connecting the laptop to PLCs. A small storage container that had odds and ends that one always forgets such as batteries for instruments or for memory backup, hose clamps, O-rings, shark bites, extra coupon holders, Teflon tape, fuses. Another container with various sized tube fitting. Lab equipment included a rubber policeman, a lab spatula, and 40-milliliter (mL) sample vials. Almost forgot the Fluke multimeter and a signal generator.

Narayanan: Toolbox: Feeler gauge to check clearance of nozzle/strainer inside a filter.

William: Water pressure gauge with fittings! How many times have you struggled with an intermittent issue only to discover nobody actually checked the incoming water pressure on the 20th floor and the real issue was the buildings booster pump.

Maxim: From now on, chewing gum will follow me on softener repair day! This trick saved me a lot of frustration while repairing a softener head! Long story short, the chewing gum is being use to hold the screw in the socket of a ratchet!

Question of the Week: Should the dechlorination point be before or after a reverse osmosis prefilter?

Todd: That is an “it depends” type of question. I have seen both. Some people say that it will help with chemical mixing if it is before. I have also seen it after because the lack of chlorine in the water allowed for bio growth downstream of the sulfite-injection point.

Abilash: Would prefer after the prefilters as a bit of chlorine prevents microbial growth on the filter elements. However, it should be before antiscalant dosing.

Tom: After the prefilter, before with a static mixer before the RO Main pump. I also like a constant feed chem pump (like the Blue White CD1 dual diaphragm or peristaltic) versus a pulsed pump.

The reason I like the feed after the prefilter is that we are only knocking down "surviving chemistry.” Prefilters are bug farms over time, with tons of nutrients. They will help consume the excess chlorine (effectively whacking bio growth), leaving less to treat on the RO feed side.

That said, always have ORP (oxygen reduction potential) on the RO feed with an alarm/system shut down when it goes above acceptable levels. Rule of thumb is we get 1,000 total ppm (parts per million) hours of chlorine exposure before the membranes are complete toast....so don't waste it on bad feeds.

Narayanan: Dear Mr. James, Good evening. Dechlorination done after prefilters (ultrafilters or sand filters or automatic self-cleaning filters) to prevent microbial fouling, increases the life of filters and sends the desired quality of feed water to the RO membrane. But, before a micron cartridge filter (5 µm), dechlorination chemicals like SBS (sodium bisulfite), SMBS (sodium meta bi-sulfite) and the dosing tank contains some undissolved fine silts and fine particles that have to be filtered by a 5-µm filter (MCF) before the RO membrane to prevent fouling of RO membrane. Activated carbon filters are also used to dechlorinate chlorine, which is usually installed after sand filters. Question of the Week Is "Everything looks good!" an appropriate summary on a Field Service Report? Why or why not?

Brian: Absolutely not. That’s the definition of complacency.

Mark: A shark also “looks” good behind the glass. Look versus Test …run the numbers and show me the data!

Robert: Use of subjective adjectives in any technical report is generally frowned upon. "The application is promising" is not something you put in a risk report when you ask for a $10-MM investment, right?

Jon: Screams drive by water treatment!

Daniel: If your customer, let's say a beverage plant, for instance, goes through an audit that will get flagged.

Laith: Possibly the pinnacle of account management if the statement is true.

John: This comment drove me crazy as a division manager! When I saw it, I scheduled an audit the next scheduled service visit and would typically give the rep a new review, finding many opportunities for improvement!

Michael: Hard to say. I've never used it. Is this account in a mythical paradise?

Des: Good morning, James. Must always be qualified “at the time of sampling”. Murphy is alive and well and his law on water sampling still applies. “Upsets occur after sampling— never before or during.”

Kevin: Yes! And please also tell me any of the locations where you find that lol. Easy pickings. Laziness is so shocking to me in this industry at times. Favorite thing to see on a competitor's report!

Question of the Week How long does the oxygen scavenger have to be turned off before conducting dissolved oxygen testing on boiler feedwater to determine deaerator performance?

Patrick: Calculate the hold time in the feedwater tank; based on capacity and the BFW pump. You then turn off the pump and wait the time for the tank to completely “turn over.” From there, I suggest using the Holy Trinity rule: Rinse three times— 3 x for sample rinse, 3 x for drum rinse outs… For example, the tank takes 20 minutes to completely turn over. Turn off the sulfite and in 20 minutes, you should mostly clear. Then wait 3 x 20 min more. If you wait too long, you risk accelerated oxygen attack.

Question of the Week How often should various components of your test kit be calibrated (e.g., conductivity meter, pH meter, colorimeter)?

Chris: I think an important addition to this discussion is that two-point calibrations should always be used and that for best practices, the standards should “bracket” the actual measurements. pH meters measuring cooling waters from, say, 7.5 to 9.2 should use 7 and 10 standards. Conductivity meters measuring pure waters and using a single 3,000 micromhos standard are probably not going to give good results at these low levels. Handheld PTSA and fluorescein meters should be calibrated daily; continuous analyzers should be checked monthly, using DI water and a calibration standard above set point.

Frank: The smart aleck answer is “RTFM,” (Read the Free Manual). The owner’s manual(s) usually states at least daily for pH and less often necessary for conductivity. Most of the folks at the AWT training tell me they calibrate pH daily or weekly and conductivity weekly or monthly. Checks against known standards on all testing meters and kits is a great idea. Especially if you notice any inconsistent results. Great topic. Catherine: It depends on usage and specifications of the meter, but in general, colorimeters should have a calibration check once a year. For traditional pH meters and conductivity meters, they should be calibrated as often as is practical but definitely before big changes in measurement ranges. For digital probes, the length of time between calibration can be increased but users should be mindful of the waters they are testing, particularly taking into account residues that could "contaminate the probe" and like traditional meters, jumping between systems with very different ranges can effect calibration.

Moderator James McDonald, PE, CWT, is a director of technology & marketing with Chem-Aqua. He holds an M.S. in chemical engineering and is a Ray Baum Memorial Water Technologist of the Year award winner (2013). Mr. McDonald also chairs the Association of Water Technologies (AWT) Technical Committee. Mr. McDonald can be reached at James.McDonald@chemaqua.com.