FREQUENTLY ASKED QUESTIONS
FREQUENTLY ASKED QUESTIONS
We get asked a lot of questions about water and wastewater treatment, mass transfer and cooling tower components. Here are the most popular.
You did not find an answer to your question? Please contact us per mail at email@example.com or by phone: +49 2233 39828 0. We are happy to help.
Question: Which material should I choose as cooling tower fill: PP (polypropylene) or PVC (polyvinyl chloride)?
Our many years of experience as manufacturer of cooling tower installations show that many users are not aware of the possibility of using PP instead of PVC as a material for fills and drift eliminators. In as early as the 1980s, however, we found a good alternative in PP. Many of our customers have used it successfully in cooling towers for decades. After polyethylene, PP is the second most commonly used plastic.
Our brochure presents the properties of the two polymers and offers a better understanding of PP as an alternative to PVC: Brochure PROPERTIES OF POLYMERS PP AND PVC
Although this brochure mainly focuses on cooling towers, certain aspects are interesting for water and wastewater applications as well. Have a look!
We recommend inclining against the flow direction for 3 important reasons:
- When installing the lamellas against the flow direction, the size of the influent zone is larger, which improves calming of the flow and reducing the flow velocities.
- Any preferred flow currents are deflected from the lamella inclination and the sludge particles directly hit the lamellas. Thus, they settle and slide down the lamellas.
In installations in flow direction, the particles enter the lamella channels without any resistance, which may result in sludge passing the channels without settling on the surface. This would mean there is only little or no sedimentation of the sludge.
- Descending sludge from the lamellas is rather taken away from the lamellas than pushed back into them.
Looking at typical designs of lamella settlers around the world, we find that the majority follows this idea.
Question: Is a round or a square tank as clarifier more cost effective regarding the lowest cost per flow rate?
Unfortunately, no general statement can be made in this regard. It depends on the individual situation and a variety of factors:
- When you intend to use lamella plates in order to have a low footprint clarifier, for example, the square tank will make it more cost effective since lamella modules, launders and a support structure can be installed more easily.
- To reach more capacity of existing round clarifiers our lamella modules will also be more cost effective than building new clarifiers.
Please contact us for more information in regards to your specific situation!
Question: How to prevent scum/floating sludge in sedimentation tanks with TUBEdek® lamella │Waste Water Treatment
From their design TUBEdek® lamellas are self-cleaning. Settled substances slide down the inclined profiles into the sludge collection section by gravity. One important step for an efficient sedimentation is to match upstream and settling processes.
However, sometimes due to certain circumstances scum and floating sludge may occur. Sludge that remains too long in the bottom of a clarifier may become biologically active and generates gas bubbles, which lift sludge upwards. This will deteriorate the unit’s performance.
The following measures can be taken against this effect:
Check the performance of the upstream processes. Maybe there are possibilies to make adjustments in order to prevent floating particles. This is the most important point as for example improved grease removal or aeration strongly affect building of scum and floating sludge. Optimizing upstream processes is the best measure to achieve an efficient settling performance.
Apart from that, you can do the following:
- Increase the frequency of sludge removal from hopper
- Discharge the sludge more frequently from the clarifier
- Increase hydraulic to design value
- Install a skimmer, which retains scum.
- Install scum-removing devices
Potable Water Treatment - What to do against discharge of flocs in sedimentation tanks with TUBEdek® lamella
From their design TUBEdek® lamellas are self-cleaning. Settled substances slide down the inclined profiles by gravity into the sludge collection section. One important step for an efficient sedimentation is to match upstream and settling processes.
Nevertheless, sometimes flocs are discharged upwards from the settlers, deposit as sludge on the wall, the interspace between the modules or in the dead space between the modules and the wall. Usually this does not influence the operation.
When to act and what to do
From their design, TUBEdek® lamellas are self-cleaning. Settled substances slide down the inclined profiles into the sludge collection section by gravity.
TUBEdek® lamella settlers need to be cleaned in regular intervals that depend on your application and the condition of the lamellas. The cleaning is easy to do if you observe some guidelines.
As TUBEdek® lamellas are strong and robust you can use pressurized industrial process water to clean them. We recommend using a flat waterjet. Start with low water flow and high pressure and continue with high water flow and lower pressure.
However, you need to be careful: Flushing should never cause vibrations of the TUBEdek® surfaces. Vibrations will cause fine cracks and damage the lamella. Do the flushing with the same attention, as you would clean a car.
We recommend training the cleaning procedure on a spare module to develop a feeling and experience for the flushing before cleaning the installed media.
HOW TO PROCEED
Typically, you clean TUBEdek® from above. Place planks on top of the lamella. They should fully extend at least over two rows placed side by side. Cleaning TUBEdek® from below is not a regular working procedure as you need to drain the complete tank.
Automatic cleaning of the lamellas does not achieve satisfying results.
Yes, you just need to follow five design guidelines:
- You need a properly designed sand and grit removal for the fast settling, mostly inorganic, matter. Aerated systems give better results and help in FOG removal.
- You need a well matching FOG removal (FOG = Fat, Oil, Grease). In combination with the before mentioned sand and grit removal it builds the pre-treatment unit.
- The primary clarifier shall remove all organic matter, mainly by settling, but will also eliminate floating substances. Here our TUBEdek lamella separator will lead to reduced tank space and enhanced settling.
- A properly selected scraper system ensures the safe removal of settled organics.
- Retention time is key depending on the down-stream processes: BOD removal allows different retention times than de-nitrification.
Do you have any questions? We are ready to help you. Please contact us at firstname.lastname@example.org or call us +49 2233 39828 0.
In waste water treatment plants, trickling filter processes are one of the least energy consuming methods. Even higher investment costs of a flat trickling filter can be compensated by energy savings during operation. Compared to activated sludge plants, trickling filters can save up to 70% costs in municipal waste water treatment.