Keeping your effluent well mixed in an above ground tank is a little different to your typical pond. The concept is still the same – you want to keep your solids in suspension to make the most of your nutrients and reduce strain on your pump, but the execution needs to be a little different. Here’s our top 3 recommendations for stirring an above ground effluent tank…plus what we wouldn’t recommend….
1. Electric Over-The-Wall Slurry Stirrers
Over-the-wall horizontal stirring is the ultimate option because it is the most effective. A more thorough stir is achieved because the stirrer can be positioned far enough into the tank and angled for the best flow. This allows the stirrer to easily break up crust from the top (should you have any) as well as bringing sediment from the bottom into rotation.
To provide the best efficiency, where possible go electric. Your running costs will be lower, and the stirrer can be automated which drastically reduces labour requirements. In the majority of cases, we find farmers with electric stirrers are able to stir their effluent tanks and ponds more often because it requires no effort.
There are two options for electric over-the-wall slurry stirrers:
Pedestal Mounted – this has been the more traditional method for electric stirring over the wall of an above ground tank. The electric stirrer is simply mounted on a pedestal to reach into the tank.
Extended Mast – A Nevada TankSstir 710 is the latest method for over-the-wall electric stirring is having an electric stirrer with an extended mast that reaches over the wall of the tank. This is more cost effective than a pedestal while also being more convenient as it is operated from the ground.
2. Electric Submersible Or Floating Vertical Stirrers
As we’ve said above, for efficiency purposes where possible go electric. Never underestimate the value of your time, and the time of your staff. Once you’ve experienced automation you’ll never look back!
That said, a submersible or floating vertical effluent stirrer are your next best options if you only have a small effluent tank. If you have a bigger tank skip to option 3.
- Submersible Stirrers – for above ground effluent tanks smaller than 300,000L these will get the job done if they are placed far enough away from the wall to allow the effluent to circulate. On principal we prefer to keep electricity out of the water, but they are good with being easy to retrieve for maintenance.
- Floating Vertical Stirrers – a floating vertical stirrer can do a good job in small above ground tanks with no more than 10-12m diameter. This size allows the stirrer to keep all the solids in suspension.
Note: Neither of these options will be as efficient as an over-the-wall electric stirrer.
3. PTO Over-The-Wall
If you’re a contractor or electricity is not an option, a PTO tractor driven stirrer with over-the-wall extension is best. These are highly efficient, and placement provides the best mixing performance, however it will tie up your tractor while you get the job done.
Over-The-Wall PTO Slurry Stirrer
Hydraulic Front End Loader PTO Slurry Stirrer
Not Recommended
A couple of common set ups we don’t generally recommend are through-the-wall stirrers and using a pump to stir. Here’s why…
Through-the-wall stirrers – these stirrers can work; however, they are likely to be less effective due to them being situated near the bottom of the tank. This means they can do a good job of preventing solids from settling at the bottom of the effluent tank, however they’re unlikely to have the ability to suck in solids from the top of the tank. Of course, through-the-wall also means compromising the integrity of your tank, so you’d want to make sure it is very well built to reduce chances of leaking.
Pump to stir – While it may seem logical to utilise your pump for stirring, in reality this is not what a pump is designed to do, and it is unlikely your pump will be adequate to get the job done. Relying on a pump to stir up a pond will prematurely wear the pump and usually results in blockages.