Capturing Ammonia From Manure: How Farms Are Turning Emissions Into Fertilizer

For decades, livestock operations have battled a stubborn trade-off: manure holds valuable nitrogen, yet a significant share escapes as ammonia gas that contributes to odor, air quality problems, and nutrient loss. A new wave of manure-to-fertilizer technologies is changing that equation by recovering ammonia directly at the source and converting it into marketable nutrients, often as ammonium sulfate or ammonium nitrate solutions. The result is a tighter nutrient loop, lower emissions, and a hedge against fertilizer price swings.

Why Ammonia Matters

Ammonia volatilizes readily from barns, lagoons, and fields, particularly when manure is warm, agitated, or exposed to air. That lost nitrogen represents a direct economic hit to farms that must later buy fertilizer to meet crop needs. Downwind, atmospheric ammonia reacts to form fine particulates that degrade air quality and redeposit nitrogen into waterways and sensitive ecosystems. Regulators in several regions now target ammonia reductions, and supply chains are scrutinizing livestock footprints more closely. Recovering ammonia at the manure stage offers a practical lever to address all three: cost, compliance, and climate co-benefits.

The Core Technologies

While designs vary, most systems revolve around moving dissolved ammonia from a manure stream into an acidic capture solution, where it becomes a stable fertilizer salt. Three approaches dominate commercial and late-stage pilot deployments.

Gas-Permeable Membranes

In these systems, a bundle of hydrophobic, gas-permeable tubes or sheets is submerged in or circulated around manure. Ammonia diffuses across the membrane and into a slightly acidic solution flowing on the other side, where it is trapped as ammonium. Because only gas passes the membrane, the capture solution stays clean, reducing fouling risk. Research groups, including U.S. public-sector labs, have reported large reductions in dissolved ammonia and marked odor decreases in swine and dairy applications when systems are appropriately sized and maintained.

Vacuum and Air Stripping

Stripping relies on pH and temperature to shift ammonium toward gaseous ammonia, then transfers that gas into an acid scrubber. Vacuum stripping lowers the boiling point to release ammonia at lower temperatures, cutting energy needs. Air-stripping towers bubble air through preconditioned manure or digestate; the outflowing air then passes through an acid column to capture the ammonia. These designs are well understood in wastewater treatment and are being adapted for on-farm flows.

Electrochemical and Bioelectrochemical Capture

Newer systems apply a voltage across membranes to steer ammonium ions into a separate compartment, where they combine with acid. Some units tie into anaerobic digesters, using available electricity to recover nitrogen while biogas provides heat for upstream processes. These modular setups are generating interest for their compact footprint and precise control, though capital costs and stack longevity are active areas of development.

What Comes Out: A Usable Fertilizer

The capture solution typically yields an ammonium sulfate or ammonium nitrate liquid with consistent nutrient content, suitable for fertigation or blending into standard fertilizer programs. For farms, this converts a volatile emission into a storable input with real value. Some operations apply the recovered nitrogen on nearby fields; others sell it to local crop growers or co-ops, depending on quality standards and logistics.

Integration With Existing Manure Systems

Successful deployments focus on where and when ammonia is most concentrated:

• At the barn or pit: Treating manure before storage prevents early losses and reduces odor in and around housing.
• Post-digestion: Digesters convert organic nitrogen to ammonium, often boosting recoverable ammonia. Capture systems placed after solids separation can be especially effective.
• During agitation and transfer: Temporary surges of emissions occur when lagoons are mixed or tanks are pumped. Portable capture units are emerging to handle these peaks.

Pre-treatment steps—screening, dissolved air flotation, or screw presses—help remove fibers that can foul membranes or packing media. Automated controls for pH, temperature, and flow balance extraction rates with energy use and chemical consumption.

Economics: Where the Numbers Pencil Out

The business case rests on four pillars:

• Fertilizer displacement: Every kilogram of nitrogen recovered is one less purchased. When synthetic nitrogen prices are elevated or volatile, payback periods shorten.
• Manure handling benefits: Lower ammonia in barns and storages can reduce corrosion, odor complaints, and worker exposure, adding indirect savings.
• Regulatory and program incentives: Emission caps, nutrient management requirements, and cost-share or carbon-oriented programs can offset capital costs.
• Co-location synergies: Farms with digesters, greenhouses, or irrigation systems can use heat, electricity, and fertigation to amplify value.

Capital costs depend on flow rate, nitrogen load, and the chosen technology. Operators report that right-sizing the system to the highest-ammonia streams, rather than treating every gallon, can materially improve returns.

Environmental and Community Impacts

Ammonia capture does more than conserve nutrients:

• Air quality: Lower barn and lagoon emissions can reduce local odors and precursors to fine particulates.
• Water quality: Less volatilization means more predictable nutrient accounting and fewer downstream losses when fertilizer use is calibrated.
• Greenhouse gases: While ammonia itself is not a greenhouse gas, closing the nitrogen loop can reduce the need for energy-intensive synthetic fertilizer production.

Operational Realities and Risks

No system is plug-and-play. Performance depends on routine tasks and design choices:

• Fouling control: Membranes and packing media need clean-in-place cycles or periodic replacement, especially with high-solids manure.
• Chemical management: Acid and alkali use must be carefully handled, stored, and tracked to protect workers and equipment.
• Energy footprint: Heating, pumping, or vacuum systems add load; pairing with on-farm power or heat recovery helps.
• Product consistency: Buyers expect predictable nutrient content; inline sensors and batch documentation are becoming standard.

Farms that pilot a skid-mounted unit on a side stream often gain the operating data needed to scale with confidence.

Policy and Market Signals

Regions with ammonia emission limits for intensive livestock housing or manure application are seeing faster adoption. Nutrient management plans increasingly account for atmospheric losses, and some procurement programs recognize manure-derived fertilizers. As measurement and verification tools improve, recovered-nitrogen credits could emerge alongside existing manure and digestate incentives.

What’s Next: Smarter, Smaller, More Connected

Several trends are shaping the next generation of systems:

• Sensor-driven control: Inline ammonia, pH, and temperature sensors linked to predictive algorithms to optimize capture in real time.
• Hybrid designs: Combining membrane contactors with low-temperature stripping to balance efficiency and maintenance.
• Modular scale: Trailer-mounted units for seasonal use during storage agitation or for custom-operator services across multiple farms.
• Product tailoring: On-the-fly blending to deliver target N-S ratios for local crops and soils, improving agronomic fit.

How Producers Can Evaluate Fit

A structured assessment avoids surprises and highlights value:

• Map nitrogen flows by location and season to pinpoint high-ammonia streams.
• Test manure characteristics—pH, temperature, total ammonia nitrogen, solids—across representative days.
• Model scenarios for fertilizer savings at conservative capture rates and prices.
• Plan for chemical storage, sensor calibration, and membrane or media maintenance.
• Engage neighbors and local regulators early to align on air and water outcomes.

The Bottom Line

Ammonia capture and conversion is moving from promising pilot to practical tool on livestock farms. By transforming a persistent emission into a predictable fertilizer, these systems offer a rare combination of economic and environmental gains. The best results come when technology selection, sizing, and operations are grounded in the farm’s specific flows and goals—turning waste into an asset, one molecule at a time.