Everything You Need to Know About Troubleshooting Issues for Your Clarifier
While slant plate clarifiers are excellent tools for wastewater treatment for large bodies of water, sometimes issues arise that require troubleshooting. Whether those issues are big or small, troubleshooting and resolving them quickly will ensure your future ability to treat wastewater.
Several issues could arise with your slant plant clarifiers, which we’ll examine in today’s blog. Keep reading to learn more about these issues and how to resolve them.
Effluent Has A High Content of Suspended Solids
If your effluent is over 20 GPM, ensure that the flow rate is within the design criteria. This can be done via the flood flow meter. If your slant plate clarifier didn’t come with a flood flow meter, you can take some measurements to determine where things are.
Measurement Instructions for Flow Rate
Start by measuring the distance from the bottom of the overflow flume to the top of the weir (the depth of water at zero flow). The ideal time to take this measurement is when there’s no flow and the water level is stopped at the top of the overflow weir plate.
Next, with the clarifier in service, stop the underflow pump and wait for the flow to stabilize. Once this has occurred, measure the depth of the water above the overflow weir plate. You’ll want to take these measurements at least one foot away from the overflow weir plate.
Once you have both measurements, subtract the first and use this formula to determine the flow rate.
Formula: F = (1/134.77)(L – 0.2H) x H1.5
H stands for water height in feet, L is the length of the weir in feet, and F is the flow in gallons per minute. If you have one more than the weir box, add the values to determine the overall flow rate through the tank.
Once you’ve determined the flow rate, check to ensure there are enough chemicals for the flow rate into the unit. The flocculating anionic polymer is most important, followed by the coagulating agent, if you use one.
Next, check for proper incoming pH.
You want good flocs forming in the flocculation tank. The right amount of polymers is essential. Too few polymers will result in the solids not settling correctly at the bottom of the tank. Too many polymers will make the solids sticky, potentially plugging the plates and discharging them from the GS’s sludge hopper.
While not all high polymer levels will result in plugging the plates and discharge, a minor excess could cause problems with dewatering equipment, such as blinding cloths on a filter press.
If the sludge removal rate is too low, you’ll have a build-up of solids in the unit that will carry over to the top. If you try a high underflow rate when there’s a buildup of solids, there will be solids on the side, ultimately resulting in clogs.
If these steps don’t resolve the high content of suspended solids, we recommend a static settling test on the influent water to the GS. This will allow you to determine if the settling velocity of the particles has changed since the last settling test. In a granulated cylinder, you can also determine the sludge volume after five minutes.
On the other hand, if the sludge particle is too low, we recommend recycling the sludge from the GS hopper back to the flash mix tank, as this will increase the overall concentration of the suspended solids, giving you a larger, heavier floc.
Sludge Concentration Is Too Low
If your sludge concentration is too low (less than 0.5 WT%), ensure that the sludge removal rate is correct. Too much will cause the sludge to discharge before it can thicken in the sludge thickener. This can be fixed by decreasing the “ON” time of the sludge removal pump or its pump rating via the air pressure setting.
Sludge Concentration Is Too High
It’s also possible to deal with the opposite issue, which can cause different problems. If your sludge concentration is too high, you’ll want to increase the “ON” time of the sludge removal pump via its air pressure setting.
Sludge Can’t Be Withdrawn from the GS
If you can’t get the sludge out of the GS, you’ll want to check the sludge pump first. It not working can easily cause this problem. Another cause is if the sludge line is blocked between the sludge tank and the discharge point. Use the recommended air blowout connection to slowly apply compressed air to blow out obstructions.
We urge you to exercise caution when applying compressed air, as it can be dangerous. Keep the psi between five to 15 for the best results, and only apply the air when the GS is not in operation.
If Liquid Overflows
It’s possible for liquid to overflow the sides of the feed box, effluent flumes, or the sides of the tank. For any of these issues, take the following steps:
Check for excessive feed rate and adjust accordingly.
Check the inlet line between the flash/foc tank and the GS tank for blockage.
Check if the holes in the effluent are open.
Check if the effluent line is blocked.
Safety Protocols When Troubleshooting
Whenever you are troubleshooting issues with your slant plate clarifier, caution is the most important step you can take. Always use an OSHA-approved ladder and platform when performing these steps. Never climb onto the slant plate clarifier.
Get Your Slant Plate Clarifiers from J Mark Systems.
J.Mark Systems offers state-of-the-art mobile slant plant clarifier systems with WTRBOX. Our clarifiers are perfect for your wastewater treatment and are easy to troubleshoot should something go wrong.
Use our WTRBOX slant plate clarifier systems for aerospace, electronics, automotive, mining, textiles, power generation, petrochemical, food and beverage, pharmaceutical, and metal finishing.
Get started today with a free water optimization audit, and see what J.Mark Systems can do for your wastewater treatment solutions.