Blog IronAxis Technical Team 24 Aug 2026 views ( )

Why South American Farms Are Replacing Windrow Composting with Enclosed Fermentation Tanks

Two defining characteristics impact all management decisions in all livestock and poultry farms in South America, size and space. A single broiler complex can have hundreds of thousands of birds. And there is usually plenty of land available for spreading manure. For years, these favorable conditions meant windrow composting – the practice of piling manure in long rows and turning it with tractor-mounted equipment – was the standard processing method. It was cheap, familiar and ‘good enough’.
But 'good enough' is shifting. Environmental agencies from Chile to Bolivia are tightening up regulations on discharge and odor. Farm managers are crunching the numbers on the real cost of labor, diesel and repeated bacterial inoculation. Where organic fertilizer buyers once were willing to accept variable quality, they now expect consistent nutrient content and certification of being free of pathogens. The windrow method is now a practical compromise, and is becoming a liability.
This gap is being filled by a new generation of enclosed processing equipment. In this article we discuss the reasons for South American farms changing from open air windrow systems to enclosed manure fermentation tanks, and the impact of this change on efficiency, cost control and product quality.
Pain Point 1: Fermentation Cycles That Drag On
Windrow composting takes time. The process relies on naturally occurring microbial activity, so the pile must heat up on its own to thermophilic temperatures—often taking three to six weeks, sometimes longer in cooler or drier months. It ties up equipment, uses up valuable yard space and is subject to disruption.
If you make fresh manure on a daily basis , and you have a large operation , a multi-week cycle creates a continuous backlog . New waste comes in before the old batch is used. This means farms are managing multiple rows at multiple stages, increasing their composting footprint and complicating logistics.
Bolong's enclosed manure fermentation tank dramatically compresses this timeline. Inside a sealed vessel, temperature, oxygen and moisture are actively controlled to maintain optimal thermophilic conditions — typically 55°C and above — throughout the entire batch. Under these conditions, the fermentation cycle is shortened to approximately seven days. The same volume of manure that would have sat in a windrow for a month is now processed, stabilised and ready for discharge in just one week. For South American farms with a high daily output, this difference in throughput is not marginal — it fundamentally changes the maths of manure management.
Pain Point 2: Total Dependence on Weather
South America's tropical and subtropical climates present a double-edged challenge for agriculture. While abundant warmth supports microbial activity, heavy seasonal rainfall, particularly in the Amazon basin and along the Atlantic coast of Brazil, can disrupt open-air composting overnight.
When rain saturates a windrow, the moisture content of the pile spikes beyond the ideal range. Oxygen pockets collapse, anaerobic zones form and the thermophilic phase stalls. Rather than breaking down properly, the heap begins to emit foul odours. During prolonged wet seasons, some farms report losing entire batches. Even when the rain stops, it takes days for the saturated pile to dry out before turning can resume, which extends the cycle even further.
A manure fermentation tank eliminates this vulnerability entirely. As the process occurs inside a sealed, insulated vessel, external weather conditions have no impact on fermentation. Rain, humidity and temperature fluctuations outside the tank do not affect the controlled environment inside it. Farms in regions with high rainfall — from Brazil's southern states to the Andean foothills of Bolivia — can therefore maintain continuous processing all year round, regardless of the season. For operations that previously lost weeks of production each year to bad weather, switching to an enclosed manure fermentation tank means permanently reclaiming that lost time.
Pain Point 3: Labor, Fuel, and Consumable Costs That Never End
Windrow composting is cheap on paper – all you need is a tractor and a turning implement. But the costs add up. Each batch requires mechanical turning every two to three days, tying up fuel, equipment hours and operator labor for the entire cycle. Bacterial inoculants add cost — the open pile loses moisture, heat and microbial populations to the environment, so they have to be reapplied several times per batch, each application adding product, labor and down time.
An automated manure fermentation tank restructures that cost profile. Temperature and oxygen are controlled automatically, sustaining thermophilic conditions with no repeated manual intervention. Inoculation happens once, at the start of the batch, inside a sealed environment where microbial populations stay stable. No tractor turning, no diesel, no repeated inoculant cost — a single operator monitors everything remotely from a control panel.
For South American farms facing rising labor costs and a shrinking pool of skilled operators, this move from constant manual involvement to automated monitoring is more than a cost saving — the manure fermentation tank redirects labor toward higher-value tasks on the farm.
Pain Point 4: Product Quality That Changes with Every Batch
The unpredictability of windrow composting is perhaps the most frustrating part for farm managers. The finished compost will vary a lot from batch to batch, because the pile is subject to variable weather, inconsistent turning schedules and uneven distribution of microbes. One load may be organic fertilizer; the next may be under-fermented, stinky, or contaminated with weed seeds and pathogens that survived the process due to cold spots in the pile.
This variability causes downstream problems. Fertilizer buyers, be they neighboring farms, commercial distributors or government procurement programs, are calling for more quality certifications with specific parameters: minimum organic matter, minimum nutrient values, maximum moisture and confirmed pathogen reduction. To summarize, a windrow operation cannot deliver consistent output.
The enclosed manure fermentation tank delivers repeatable, certifiable quality. Every batch processes under identical controlled conditions — the same temperature profile, the same oxygen delivery, the same residence time. The result is a uniform product that meets or exceeds organic fertilizer standards on every cycle.
To illustrate with measured data from a Bolong installation: the finished organic fertilizer tested at 52 percent organic matter (against a standard minimum of 45 percent), total nutrient content (N + P₂O₅ + K₂O) of 11.9 percent (against a standard minimum of 5.0 percent), and moisture content of 22 percent (against a standard maximum of 30 percent). Fecal coliform bacteria tested negative, and Ascaris eggs were not detected — confirming thorough pathogen elimination at the thermophilic processing temperatures the system maintains. Heavy metal content tested well below national standard limits across all measured parameters.
These are not estimates or industry averages. They are laboratory-measured results from an operating system. For South American farms seeking to sell organic fertilizer into regulated markets — or simply to demonstrate compliance with tightening environmental rules — this level of consistency and verifiable quality is the difference between a saleable product and a disposal problem.
The Scale Factor: Why It Matters More in South America
South American livestock operations are typically larger than those in other parts of the world. A single poultry complex can produce tens of tons of fresh manure daily and cattle feedlots in Brazil and Argentina produce in volumes that outstrip windrow logistics. Abundant land was the very reason windrow composting was viable in the first place. It’s a moot point, though, when waste generation outpaces processing throughput.
This is handled by modern manure fermentation tank systems such as Bolong’s 11FFG series, by scalable capacity. Individual tank volumes are between 102 and 280 cubic meters, and several units can be installed in parallel to meet any farm’s daily output. A 30-tonne-per-day farm can set up a multi-tank system that requires a seven-day cycle to process each batch, producing steady throughput without the sprawling footprint and labor overhead of equivalent windrow operations.
Start with One Tank
The transition doesn’t require farm managers considering the switch to throw out existing infrastructure overnight. Many South American operations start with a single manure fermentation tank next to their windrow system, which processes their highest-priority waste stream and allows for performance assessment. Additional units are added incrementally to replace windrow capacity, once throughput, quality and labor savings are proven in practice. This step-by-step approach reduces capital risk, builds hands-on experience and begins producing certified quality organic fertilizer – and revenue – sooner.
The first step is simple: Identify where windrow composting is costing you the most — whether it’s cycle time, weather delays, labor hours or rejected product. The story we hear from South American operators is the same: the hidden costs of open-air composting have outweighed the visible savings.
Share your daily manure volume, your current processing method, and the single biggest bottleneck in your operation. Bolong will customize an industrial manure fermentation tank configuration to match your farm's specific needs — with an optional deodorization system available on request.