Manure Centrifuge Separator
Manure handling and disposal in the livestock industry is one of the critical factors affecting cost and viability in a highly competitive market. Effective waste handling can bring higher revenues from a previously resource-intensive operating expense.
Why Separate Manure?
The separation of manure into its solid and liquid components is important for two reasons. Firstly, the value of dry manure is much more than that of the wetter kind. Secondly, dry manure solids’ transportation is practical and cost-effective compared to manure cost with a large water percentage.
Besides, the solids’ physical separation reduces the phosphorus, which is crucial for the separated water’s disposal consideration.
Separation of Manure
The separation of manure is the process of fractionating the manure into its liquid and solid phases. Separated manure sludge yields more value as a fertilizer and is easy to transport. The water separated from the manure is mostly free of solids and nutrients, making it suitable for disposal.
Physical means of manure separation range from gravity-separation in lagoons to media separation devices (presses) and mechanical separator centrifuges. Though each of these separation methods has a role in the livestock industry waste management, the decanter centrifuge is the most durable, cost-effective long-term solution.
Centrifuge Separator Operation
A decanter centrifuge separates manure solids from the water using high centrifugal forces over 3,000 Gs. The manure solids are heavier and settle out to the decanter bowl wall. The relatively lighter water stays in the center and flows out the liquid end. The rotating conveyor scrapes the separated solids to the solids’ end of the bowl.
It is important to note that most Phosphorus is bound to the solids and therefore ends up the separated solids. About 50% of the Nitrogen is retained in the liquid manure.
The introduction of some chemical flocculant enhances the separation process allowing for smaller particles, less than 50 µm to be separated.
The following are the specifications for a typical Alfa Laval decanter centrifuge for manure separation.
|Processing Capacity||25 GPM on Untreated Liquid Manure|
|Centrifuge Type||Horizontal, Scroll Type Decanter Centrifuge|
|Bowl Speed||4,000 RPM|
|Centrifugal Force (RCF)||3,150 Gs|
|Scroll Differential Speed||6 ~ 50 RPM|
|Gear Box (Torque & Type)||2.5 kN-M; Planetary|
|Motor Power||15 HP (11 kW)|
|Dimensions & Weight||3′ x 8′ x 5′ (H) 2,500 Lbs|
Benefits of Manure Separation
- Higher Value of Liquid Manure
The centrifugal solids separation leaves the separated liquid with minimal Phosphorus. This reduction in P-content vastly increases the applicability of liquid manure as fertilizer.
- Reduced Storage and Transportation Costs
Separated phases (solid and liquid) are much easier to handle and store as needed. Solids can be further dried and stored for longer terms. Considerable reduction in volume is the key to transportation-related cost benefits.
- Higher Value Fertilizer
The retained nutrients and Phosphorus in the separated solids can be used as periodic fertilizer or even sold as a more organic substitute for expensive, commercial chemical fertilizers.
- Dredging Cost Savings
Upfront solids separation using a centrifuge means lesser solids ending up in the open pits or lagoons. The storage pits maintain their capacity without the need for frequent dredging to reclaim storage volume.
Advantages of Centrifuges
Centrifuges offer many advantages over other mechanical separation devices like filter presses, belt presses, etc.
- Separation Efficiency
With centrifugal forces over 3,000 Gs, centrifuges can separate solids in the 25 ~ 50 µm range. Other conventional technologies only go down to 300 µm level or higher.
- Drier Solids
Solid cake dryness is adjustable with a decanter centrifuge. Solids with 50% dryness are attainable using pond-depth adjustment of the centrifuge. Drier solids are easier to transport and readily applicable as fertilizer.
- Reduce or Eliminate Chemical Use
With the use of centrifugal force to enhance separation, flocculants and other separation aids are significantly reduced, leading to immediate cost savings.
- Minimum Labor Cost
The purely mechanical separation offered by centrifuges allows for unattended and reliable separation of manure solids. This reliability reduces labor costs associated with presses and other mechanical separation methods.
- No Media Costs
Since centrifuges do not use any separation media (like filter mesh, paper, or cloth), recurring costs related to such consumables are eliminated. This saving also reflects on the used media disposal costs.
For specific manure separation inquires, please click below or call Dolphin Centrifuge @ (248) 522-2573 to speak with one of our application engineers!