Their are few things to think about when choosing the right size effluent bladder tank for storage on your farm.
Understanding Your Farm
When you get someone in to calculate your storage requirements make sure they have a good understanding of how your farm operates. A storage calculator will assume you take every opportunity to irrigate, which is not always the case. For example, many farmers that winter milk would prefer to have plenty of storage, so they don’t need to worry about effluent over winter.
Cow Numbers
A common misconception is that storage requirements are proportional to cow numbers. While cow numbers do influence the storage calculation, they are just one of a few considerations.
Soil Type
Soil type is a major influence on how much storage is needed. Soil drainage directly affects your ability to irrigate. If you can’t irrigate, you’ll need to be storing effluent for longer.
Effluent bladder tanks are particularly beneficial for soil types with poor drainage and/or high rainfall areas. The closed storage means you don’t need to account for rainwater in the storage calculations. However, it is also important to have a good stone trap to ensure unwanted debris are not making it into the effluent bladder tank. These can be difficult to remove once inside.
Effluent Source
The next thing to consider is where the effluent is being caught from (other than the cows) and how much is being caught. Feed pads and stand-off areas generally have more concrete, allowing for more effluent to be captured.
Land Application
Finally, you’ll want to consider how you’ll be applying the effluent to land. The applicator depth affects how often you can irrigate. This is important for council consent, so be realistic about your application depth.
Remember, storage calculators are based on weather patterns over the past 30 years, but the past doesn’t always predict the future. They also only calculate the minimum requirements and will assume you’re taking every opportunity to irrigate. In most situations our advice is to get more storage than the minimum requirements set out in the storage calculations.
While all these considerations may seem like a lot, if you’re working with a good effluent management consultant, they’ll make the process like a walk in the park. If you can give them a good understanding of your farm, they’ll be able to recommend the right size effluent bladder (or various options) to suit your situation.
