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Enviromental Business Specialists (EBS) state that primary clarification can remove more Biochemical Oxygen Demand (BOD) than a biological system especially in paper mills. This is because of the fiber in the waste stream can be detected as “phantom” BOD. This “phantom” BOD can causing loading to the system.

EBS points out the clarifier effiency is based on temperature of the water, hydraulic detention time, the con­dition of the equipment and the design of the tank. Poor clarifier performance can be due to the list below.

Reasons for Poor Clarifier Performance in your Waste Stream:

1. Hydraulic overload which decreases hydraulic detention time.
2. Hydraulic under-load which doesn’t allow the equipment to work efficiently.
3. Sludge buildup which causes decreased tank volume.
4. Highly concentrated waste streams.

Primary Clarification is the removal of solids from before biological treatment. EBS states that it is the most cost effective way to remove these solids after basic screening of your wastewater. These solids are the scum and sludge that sit on top and at the body of the tank. EBS has recorded the expected range for percent removal in a primary clarifier. The range is 90%-95% settleable solids, 40%-60% suspended solids, and 25%-50% total BOD₅. For more information on how EBS can help you with your wastewater issues visit there site here.

EBS states that the most common cause of poor aerated stabilization basin performance is the loss of retention time. They also state that poor performance of your aerated stabilization basin can also be an issue with either food loading, pH, toxicity, aeration, nutrients, biomass, and temperature. To get an accurate assessment of the issues you may be having it is best practice to perform a complete evaluation of your aerated stabilization basin using a tracer study, depth profile, profile sampling for numerous parameters and possibly a treatability study. EBS believes that if you do not order these type of studies then it could be very costly in the long run.

EBS gives a list of common questions that could be signs that you need to perform a tracer study to determine retention time, flow patterns and basin capacities. Here is that list:

Questions that Should Lead to a Tracer Study on Your Aerated Stabilization Basin

• How soon do spills reach the effluent?
• Does my ASB have any channeling?
• What’s the integrity of my baffles?
• What improvements can I make to my system?

Environmental Business Specialists (EBS) recommends the use of Lithium for tracer studies instead of using fluorescent or biological tracers. They believe that Lithium is easy to recover with good analytical precision. They also state that tracer studies are not just measures of the concentration over time of Lithium leaving your system, but of study design and interpretation. They also perform pond Lithium profile studies to help determine flow patterns and performance parameters.

More from EBS on tracer studies:

For tracer studies to continue to be a useful troubleshooting tool, they must be performed regularly to determine changes in sludge loading and flow patterns. Many mills schedule a tracer study every year or every other year to obtain the historical data and monitor pond changes both from an operational point of view but also from a budgeting perspective. A sample analysis of a comprehensive tracer study is available for your review.

For more information on EBS services in wastewater treatment visit here.