When considering the purchase of fermentation equipment, pig farmers most frequently ask: ‘Are fermentation tanks really worth it when they’re so expensive?’
There is no one-size-fits-all answer, but a clear approach is to let the numbers speak for themselves. This article breaks down the differences between traditional composting and fermentation tanks in terms of labour, land, operational costs, and revenue generated, based on typical operations at a medium-sized pig farm.
Why look at the long-term bottom line rather than just the purchase price?
The initial investment required for traditional composting appears much lower-the cost of a turning machine and site preparation is usually far less than the purchase price of a single closed fermentation tank. This is why most farms initially assume that ‘the traditional method is more cost-effective’.
However, this assessment overlooks a critical fact: equipment costs are a one-time expense in the first year, whereas labour, land and operational costs are recurring annual expenses. It is precisely these recurring costs, year after year, that determine final profitability.
The Largest Cost Disparity: Labor
This is the most important difference between the two approaches and it is one of the most important things to remember.
The conventional windrow composting method requires regular manual labor such as turning, watering, sampling and temperature monitoring. Three to five workers are needed continuously at a typical medium-size manure treatment site. Instead, the sealed fermentation tanks are fitted with automatic air ventilation, mixing and temperature control systems. Only one worker is needed to carry out the daily work of loading and unloading, and routine inspection.
The monthly savings on wages for two to three workers adds up to a lot of money over time.
Land Costs: An Easily Overlooked Hidden Expense
Traditional composting requires large open-air areas for the windrows themselves, access lanes for turning equipment and leachate collection zones. Together, these typically require hundreds of square metres of paved space. In regions with limited land resources, this represents a significant annual expense.
In contrast, a single closed fermentation tank typically occupies an area of 60–70 square metres or less. It can be installed in existing factory buildings or outdoor spaces, which effectively reduces space costs.
Organic Fertilizer Output Quality: Stability and Consistency
During the months-long fermentation process of traditional open-air composting, nitrogen is prone to volatilisation and loss in the form of ammonia. Additionally, uneven moisture evaporation can lead to inconsistent decomposition levels across different batches. In contrast, the fully enclosed environment of a closed fermentation tank effectively minimises nutrient loss during decomposition, resulting in more consistent and predictable output.
This is not merely a theoretical assumption. Below are third-party test results for the actual output of Bolong fermentation tanks:
The organic matter content exceeds standard requirements by 15%, the total nutrient content is almost 2.4 times higher than the standard, all heavy metals are well below the permitted limits, and cadmium was not detected. Such consistent output is difficult to replicate with the batch-to-batch variations inherent in traditional open-air composting.
Beyond the Numbers: Three Underestimated Long-Term Benefits
A simple cost comparison is not sufficient. The following three points are all equally important when making a decision:
1、Environmental compliance risks
The odours and leachate generated by traditional open-air composting are subject to increasingly strict environmental regulations in many regions. If a complaint is filed or an enforcement inspection is triggered, the potential rectification costs could far exceed the initial savings on equipment costs. Closed fermentation tanks eliminate emission issues at source, thereby mitigating these risks.
2、Product certification and market access
As shown in the above table, the output parameters of fermentation tanks not only meet, but significantly exceed, standards. This makes the product more likely to pass various organic fertiliser certification tests, command higher prices in certain markets and meet export standards under specific conditions.
3、Labour trends
Labour costs continue to rise globally and it is becoming increasingly difficult to recruit workers year on year. Reducing reliance on manual labour is a cost-saving measure in the short term and will provide a sustainable competitive advantage in the long term.
Which Approach Is Better Suited for Your Farm?
If your farm meets any of the following conditions, the advantages of the fermentation tank solution will be even more evident:
Daily manure processing volume reaches a certain scale
Currently employ multiple workers dedicated to manure processing
High site rental costs or limited space
Plans to sell or export organic fertiliser
Local environmental regulations are becoming stricter
For small-scale, free-range farms with ample labour and space, the low initial investment of traditional composting makes sense. However, such scenarios are becoming increasingly rare against the backdrop of large-scale farming.
A fermentation tank is an infrastructure investment, not a consumable expense. Once the long-term costs and benefits have been carefully calculated, the optimal choice becomes clear.
If you would like a customised calculation based on your farm’s specific conditions, please click here to contact us for a free solution assessment.
