Turnkey Solution Using GFS Tanks for Chicken Manure into Biogas in Vietnam

Vietnam's poultry herd has expanded rapidly, driven by rising domestic meat demand and the shift from backyard flocks to concentrated layer and broiler farms across the Red River Delta, Mekong Delta, and Dong Nai. The resulting chicken manure stockpile is a recurring source of river pollution and odour disputes. This guide outlines a turnkey chicken manure into biogas package—anchored by GFS tanks, double membrane roofs, and a balanced CSTR digestion line—that helps Vietnamese farm operators monetise manure as biogas, fertiliser, and electricity while complying with national environmental discharge rules.

Vietnam currently raises well over 600 million chickens annually, and the Ministry of Agriculture and Rural Development continues to push for larger, more biosecure industrial farms. While small household flocks once dispersed manure widely, today's concentrated layer complexes—often 30,000 to 100,000 birds on a single site—produce tonnes of droppings every day in a small footprint. In the Red River Delta and the Mekong Delta, manure is frequently piled near ponds, sold cheaply as raw fertiliser, or flushed into irrigation canals. The visible results are eutrophic waterways, fish kills after rain events, strong ammonia odour affecting nearby schools and villages, and methane released without capture. Circular-economy policies and tighter environmental inspections mean that Vietnamese integrators now need a predictable, engineered route for chicken manure rather than ad-hoc dumping.

Chicken manure into biogas is attractive because it turns a disposal cost into three savings or revenue streams. The biogas displaces LPG or diesel used to heat poultry houses and power incubators, and can be exported to the grid where regulations allow. The separated solids become an organic fertiliser sold to vegetable, coffee, or rice growers, replacing part of the chemical fertiliser budget. The stabilised liquid effluent no longer causes fish kills, so farmers avoid penalties and complaints. The processing sequence begins with mechanical bar screening to pull out feathers, litter, and large debris, followed by crushing and grit removal. The screened liquor is lifted to a homogenisation tank, where mixing equalises flow and temperature before it enters the anaerobic reactor. After digestion, effluent passes through a buffer tank and a solid-liquid separator, and the liquor may be stored in a black-film pond before controlled land application.

For Vietnam's high-volume layer operations, the Continuous Stirred-Tank Reactor (CSTR) is the dominant digestion technology. CSTR treats chicken manure and other organic substrates under anaerobic conditions inside a closed, insulated tank where feedstock and microbial culture are continuously mixed. The mechanical stirring system—comprising an agitator shaft, paddles, and a top-mounted drive—keeps the thick, fibrous poultry slurry homogeneous, prevents floating crust and grit settlement, and ensures that active bacteria contact fresh substrate. Feed enters semi-continuously through the feed inlet, and stabilised sludge is withdrawn through the sludge discharge point. The reactor carries a dedicated biogas pipeline and a positive and negative pressure protector to safeguard the tank against vacuum or over-pressure. Operating at a controlled mesophilic temperature, the CSTR reliably converts the organic load into biogas, reducing volume and pathogens while producing a steady energy gas.

Biogas leaving the digester must be conditioned before use. The gas first passes through a dehydration unit to knock out water, then a desulfurisation unit to remove hydrogen sulfide that would otherwise damage generators and boilers. A booster fan feeds the treated gas at stable pressure through a flowmeter to the utilisation point. Typical end uses in Vietnamese farms include: burning the gas in a boiler to supply hot water for poultry house heating and disinfection; running a biogas generator to offset grid electricity; installing a flare system to safely burn off excess gas during maintenance or low demand; and, for larger projects, upgrading to compressed natural gas at over 95% methane for vehicle fuel or pipeline injection.

GFS (Glass-Fused-to-Steel) tanks are the preferred digester and storage vessel for Vietnamese biogas plants because their enamel coating is formed when the steel plate is fired at 820 °C–930 °C, creating an inert inorganic bond that resists the corrosion caused by ammonia, acids, and moisture in poultry slurry. The 2C2F double coating layer applies separate interior and exterior ground and surface coatings, extending service life in tropical rain and humidity. On top of the digester, a double membrane roof functions as both a weather cover and a flexible gas holder. Compared with building a separate ground-mounted gas holder, the double membrane roof directly reduces roof cost, cuts the plant footprint, and saves foundation works—an important benefit on tight, flood-prone Vietnamese farm sites.

Center Enamel matches tank material to each process duty:

• Glass Fused To Steel (GFS) tanks: flagship vessels for digesters, buffer tanks, and leachate storage, with a 2C2F dual-coating system and global certifications.
• Galvanized Steel Tanks: offer a tough, wear-resistant, durable protective coating for general water collection and equalisation service.
• Fusion Bonded Epoxy Tanks: developed in partnership with a global coatings leader for balanced corrosion resistance.
• Stainless Steel Tanks: in AISI 304/316, reserved for high-purity water and the most corrosive duty streams.

A complete turnkey package includes the auxiliary hardware that links tank and reactor:

• Gas Holder: stores conditioned biogas and smooths out peaks between reactor output and engine demand.
• Black Membrane pond liner: covers polishing or effluent storage lagoons and captures fugitive methane.
• Solid-liquid Separator: dewaters digested effluent, producing fibrous organic fertiliser and a manageable liquid stream.
• Torch System: provides safe pressure relief and continuous flaring when downstream equipment is offline.
• Lifting Pump: transfers manure and sludge between the homogenisation tank, reactor, and buffer tank without blockage.
• Dehydration and Desulfurization Tank: cleans raw biogas before it reaches the generator or boiler.
• Screw Sludge Dewatering Machine: further dewaters separated sludge for easy transport and soil use.

For Vietnamese poultry investors, working with Center Enamel means one accountable partner across the whole project:

• EPC service: from process design and civil coordination to installation supervision and commissioning.
• Process Package: a balanced pre-treatment, CSTR reactor, biogas handling, and digestate treatment system sized to the farm's daily throughput.
• Equipment Supply: GFS tanks, double membrane roofs, separators, pumps, dewatering machines, and gas treatment units delivered on a single schedule.
• Certified build: manufactured under ISO 9001, with CE/EN1090, NSF61, WRAS, and EN28765 references and designs aligned to AWWA D103, OSHA, EN28765, and EuroCode.
• Proven scale: a 150,000 m² R&D and production base, 250,000 sheets per year capacity, 500+ employees, and references in more than 100 countries.
• Responsive support: tailored proposals for small-to-mid industrial farms as well as large integrator schemes.

Vietnam's poultry industry is at a turning point: rising herd concentration, stricter discharge inspections, and volatile energy prices make open manure dumping both risky and expensive. A turnkey chicken manure into biogas plant built on GFS tanks, a CSTR digester, and a double membrane roof converts daily litter into on-farm electricity, heat, and fertiliser, while cutting odour and protecting rivers. With the right EPC partner, even a mid-sized layer complex can close the loop and become a model circular-economy farm.

Q1: What is the difference between CSTR and other anaerobic digesters for chicken manure?

CSTR digesters fully mix the slurry with mechanical agitators, which suits the high-solids, fibrous nature of chicken litter. Fixed-dome or floating-drum digesters work for dilute slurry but struggle with crust and grit when fed with bedding-rich chicken manure.

Q2: Does chicken manure need to be pre-treated before entering the digester?

Yes. Feathers, wood shavings, grit, and large bedding pieces must be screened and crushed upstream, and the slurry should be homogenised and heated before entering the CSTR, otherwise pumps and agitators will clog and biogas yield will drop.

Q3: Can the biogas from chicken manure be used directly in a generator?

It should not. Raw biogas contains moisture and hydrogen sulfide that corrode engine parts. It must first pass through dehydration and desulfurisation units, then be metered and regulated before reaching the biogas generator or boiler.