Our previous article, Food Industry Lagoon Aeration: An Overview, discussed the challenges of food industry wastewater treatment in general; in this article, we’ll outline the three particular wastewater challenges of egg processing lagoon treatment and present solutions.
The Egg Processing Lagoon
An Egg Processing Lagoon can be a simple, low cost and low maintenance method of handling egg processing wastewater. However, problems like excessive Total Suspended Solids (lagoon TSS), high Biological Oxygen Demand (lagoon BOD), and lagoon odors are a particular challenge for egg processing lagoons. This article will demonstrate how sufficient mixing and aeration are critical to reducing lagoon BOD, TSS, and lagoon odors and assuring compliance with your effluent requirements.
Particular Challenges of an Egg Processing Lagoon
Egg processing can create large amounts of wastewater, which needs to be processed in a complete, cost-effective, and efficient manner. Some of this water is sanitizing washwater, which may contain cleaning chemicals. Egg processing wastewater is contaminated with biological solids like fecal matter, feathers, shell fragments, and high protein egg contents from breakage. These substantial organic loads require high dissolved oxygen (lagoon DO) levels; without sufficient lagoon DO, the bacteria and microorganisms do not have enough oxygen to break down the BOD. Moreover, egg processing wastewater tends to have high lagoon TSS, which must be kept in suspension. Without intense mixing, the solids will either settle to the bottom of the lagoon, or, in the case of egg proteins, float to the surface of the water, where they will build up and form a dense sludge mat, which reduces lagoon capacity, can damage the lagoon aeration system, and creates odor, requiring expensive and inconvenient sludge removal or remediation. For more information see our post on Wastewater Lagoon Sludge: Treatment or Removal?
Like any food industry wastewater, lagoon BOD, lagoon DO, and lagoon TSS levels are regulated in egg processing wastewater and must be kept within limits, or a facility risks fines for violation, which, in addition to being costly, can also disrupt production. If your facility has already broken permit, our Emergency Aeration Service can help you diagnose the source and have an egg processing lagoon treatment system onsite in a matter of days.
Egg Processing Lagoon Case Study
The Lakewood wastewater treatment facility in Lake Odessa, Michigan, received effluent from an egg processor. The flow equalization lagoon, outfitted with surface aerators, was not up to the task. The surface aerators could not maintain a sufficient lagoon DO and failed to create enough lagoon mixing, causing the following problems:
- Floating sludge: Due to ineffective aeration and mixing, the lagoon DO levels were extremely low, causing the lagoon to become septic. Solids rose to the surface and a floating sludge blanket over a foot thick in areas formed. The sludge blanket caused the surface aerators to malfunction, and the entire lagoon had neither mixing nor aeration.
- Terrible odors: Complaints about lagoon odor were registered from over a mile away.
- Inadequate mixing: The surface aerators struggled to effectively mix the entire water column. Once the surface aerators became buried in the sludge mat they were rendered ineffective.
- High lagoon TSS and BOD: Without aeration, high levels of TSS and BOD were present in the lagoon as no treatment was occurring.
Unlike other types of TSS, egg proteins have the propensity to float. At Lakewood the buoyant egg protein sludge floated above the surface aerators, resistant to treatment and causing the equipment to malfunction.
In 2012, the Michigan Department of Environmental Quality mandated that the lagoon mixing and odor problems be rectified.
Rather than resorting to taking the lagoon offline and dredging it—a costly prospect—Lakewood pilot-tested four MARS Lagoon Aerators. The first challenge was to install the MARS Lagoon Aerators at the bottom of the lagoon—the sludge accumulation was so thick a 600 lb. concrete weight was required to break through. Once installed, the MARS Aerators made immediate improvements:
- Eliminated floating sludge: Within minutes, the sludge mat began to break up.
- Reduced objectionable odors: Within one day, odors were noticeably reduced.
- Improved mixing: The mixing intensity provided by the coarse bubble diffusion of each MARS aerator kept solids in suspension to promote biological digestion.
- Reduced TSS and BOD to required levels: Aeration provided by the fine bubble membrane improved DO levels, reducing TSS and BOD.
A year after installing the pilot MARS Lagoon Aerators, Lakewood added an additional 44 units to completely mix the lagoon. For a closer look at this installation, read Wastewater Lagoon Mixing Alleviates Odor & Sludge Issues.
Aeration and Mixing Fix Egg Processing Lagoon Challenges
Egg processing lagoon aeration is the process by which mixing and oxygen combine to create an active aerobic treatment environment, where bacteria and microorganisms naturally break down and metabolize lagoon BOD and lagoon TSS. The effectiveness of a wastewater aeration system depends directly on its ability to both aerate and mix. Without proper aeration, a lagoon will fail to meet its effluent requirements—at that point, installation and operation & maintenance costs will become of lesser importance in comparison.
The MARS Lagoon Aeration diffuser is ideal for egg processing wastewater lagoon treatment because it provides mixing and aeration in a single modular unit. The patented Double Bubble™ technology combines a fine bubble membrane for efficient oxygenation with a coarse bubble static tube aerator for intense turbulence and mixing to treat the entire water column. Because the MARS is installed at the bottom of the lagoon, floating egg proteins cannot escape the treatment area as they can with surface aerators.
Together, these components allow the MARS diffuser to oxygenate and treat water effectively while still using energy efficiently. The Triplepoint MARS system also features a portable design—each unit has its own weighted legs and is fed air via flexible weighted tubing. With its flexibility in placement, it can be utilized to manage practically any wastewater treatment cell by simply lowering it in from the surface.
While all wastewater treatment lagoons require mixing and aeration, it is particularly critical in egg processing wastewater because of the high levels of BOD and TSS and the tendency for egg proteins to float, putting them out of reach of surface aeration.