Gravity Separators, DAF, and Primary Clarifiers:

Alloy works on numerous wastewater systems, and has done so since the early 1960’s. 

My first boss explained the gravity separator to me in the terms of a river.  When the river is narrow and the water is running fast the particulate or sediment in the river does not settle.  However, if it hits a wide spot where the water slows significantly the sediment will drop out.  The solids in your waste water do just that in the gravity separator.  They settle to the bottom of the unit due to decreased velocity and because of the design of the unit. 

There are a few niche applications where our product really shines.

Niche #1 – Plants that do not have waste water clarification equipment and have a limited budget for wastewater.

The Gravity Separator (Primary Clarifier, Skimmer) is a relatively simple device and it has a much lower investment than most wastewater solutions, yet it can have tremendous results in the right applications.  Many units have been installed in these applications and the Alloy unit is hard to beat when it comes to a first-time wastewater pollution control device.

For a quick reduction in fees from your local municipality where you are getting charged for excess BOD, COD, TSS or FOG the Alloy unit is perfect for a rapid return on investment. By mechanically removing the solids and fats without, in many cases, the need for chemicals, the overall quality of the water sent to the municipal water treatment facility is greatly improved.

This reduces your TSS (total suspended solids) and reduces your BOD (biological oxygen demand).  Some customers (potato product manufacturers for example) have significant heavy solids.  The Alloy unit is perfect for this type of application.  Unlike other manufacturers, the Alloy unit scrapes the bottom and the top continuously, so heavy solids, like soil, are removed quickly.  Other applications require much more time for the solids to go to the bottom.

Fats that are lighter than water - If you have a plant where fat is affecting your FOG level and surcharges then the Alloy unit is a good fit.  The water that Alloy excels at cleaning is applications where the particulate is either heavier than water or lighter than water.  All animal fats are lighter than water, so they will float to the top given the right set of circumstances like in our unit.  Most vegetable oils will also naturally float so in applications where we have solids and fat the Alloy unit is a good fit.  We remove the fats and solids at the same time.  Many customers remove the fat and solids without chemical addition in the Alloy Gravity Separator.  This is ideal for reclaiming the fat and solids where the product can be sold to a rendering company.  Most customers today use polymers and flocculants to aid in reducing the FOG, TSS, and BOD levels.

Niche #2 – Plants that have wastewater equipment but current load is greater than the capacity of wastewater equipment.

For example, say a plant that is running at 180 gallons per minute (GPM) but the wastewater system is rated for 120 GPM.  Alloy has sold many gravity separators to plants big and small that are in this situation.  The way it works is that they purchase a large unit at a low investment and the Gravity Separator removes the easy stuff.  In other words, they use our unit to remove the easy fat and solids.  This greatly reduces the FOG, TSS, and BOD load on the rest of the system.  So even though the remainder of the wastewater system is still undersized, the reduced loading is enough to allow the existing system to work properly getting them back into compliance and achieving the results they want at a fraction of the cost of a new system.

Niche #3- Large plants where chemical costs are high

Some plants purchase the Gravity Separator and install it ahead of their existing Dissolved Air Filtration (DAF) system to remove much of the FOG, TSS and heavy solids without chemical addition.  Some of these units utilize our aeration systems for enhanced performance while others do not.  The payback here comes in the form of reduced chemical costs.  If a majority of the water is cleaned without chemicals, then the amount of chemicals used in the remainder of the system is reduced as the ppm of FOG, BOD, and TSS is lower. So these customers save investment on polymers and coagulants.

Niche #4 – DAF at a reduced investment

Many units today are used as a DAF with chemical addition and aeration.  Most of these units are stainless steel as the chemistry used to aid in TSS and FOG removal lowers the pH and it will attack carbon steel.  Alloy has many competitors in the DAF manufacturing arena.  The main advantage we have in this category is a reduced investment.

There are many critical aspects of the design of our unit that we have learned in the past 60 years of building this product line.  The retention time is critical as is the surface area when compared to volume of the tank.  The ability to hold the proper water level at all times, and the areas where to bring water in aeration and chemical addition, etc.

Applications where the Alloy Gravity Separator is not a good fit.

If you have large amount of soluble proteins or sugars that are the same weight or dissolved in the water, then the Alloy technology is not for you.  Here is an example, say you take sugar and dissolve it in water.  This sugar will not rise to the surface or sink to the bottom.  In applications like this our technology is not what you are looking for.

Jar Test – One of the simplest tests that you can run yourself is a simple jar test.  Take your wastewater and put it in a glass jar.  Put the sample on your desk and wait one hour.  If you see solids on the bottom of the jar, fat at the top of the jar, or both then our unit will work in your application.

Onsite testing- Alloy has found that analyzing water and trying to determine performance results is difficult and not very reliable.  So, our approach is to send our customer a small gravity separator and test with that for a nominal fee.  With this approach, the customer knows exactly what our unit will do and they can experiment with and without chemicals.  This takes the guess work out of the equation and the customer has real results. I have worked here for over 30 years and every test unit we have ever built has been kept by an end user.  For many customers, the test unit is not large enough for their volumes, so after testing they can choose to purchase or not purchase the unit sized for their application.  On many of the test clarifiers, even though unit is too small for the application, the unit has gotten good enough results that they just kept the unit instead of returning it and getting the properly sized unit.  As of this writing in early 2021, the test unit is brand new and has never been run as the last test unit was kept by the end user.  The test unit is rated for 33 GPM.

Low Maintenance without babysitting

The Gravity Separator is a low maintenance unit and it does not require an operator.  It is a plug-and-play device where an operator can check on it once or twice a day.  It does not require constant adjustments and it operates on fractional horsepower drives, even on very large units.  Virtually all customers like the fact that the unit runs 24/7 without needing someone to be watching it.

So, if you are looking to reduce waste water surcharges by reducing FOG, TSS, and BOD in a reasonable cost unit from a company with hundreds of installations and 60 years of product improvements then call one of our application engineers and we will see if we can help you.