Village Livestock Waste Management in Vietnam: Modular Biogas Systems by Henan Zonghai Plastic Industry

Project Overview

Vietnam has one of the largest smallholder livestock sectors in Southeast Asia. Many rural households raise pigs and poultry as part of integrated farming systems, producing significant quantities of organic waste.

In 2023, Henan Zonghai Plastic Industry Co., Ltd. participated in a supply project involving modular biogas digesters for a rural village in northern Vietnam. The goal of the project was to help several farming households convert livestock manure into renewable cooking fuel while improving local waste management practices.

The case offers insights into how flexible digester technology can support decentralized waste treatment in rural environments.

Agricultural Context

The participating village consisted primarily of small family farms raising pigs and chickens alongside rice and vegetable cultivation.

Typical livestock numbers per household included:

• 12–25 pigs
• 50–100 chickens

Manure from pig pens was traditionally washed into small drainage channels or stored in shallow pits. During the rainy season, this waste could accumulate near homes and contribute to unpleasant odors.

At the same time, most households relied on purchased LPG for cooking.

The village authorities were therefore interested in exploring biogas systems that could address both waste management and energy needs.

Identifying the Key Challenges

Before the installation of biogas systems, several challenges were identified:

Limited land availability

Traditional underground digesters require significant excavation space, which was difficult to allocate in densely built village areas.

High groundwater levels

Seasonal rainfall often raised groundwater levels, increasing the risk of water infiltration into underground structures.

Need for simple maintenance

Households required equipment that could be operated without specialized technical knowledge.

These factors made modular flexible digesters a suitable option for the project.

Digester Design and Technical Parameters

Henan Zonghai Plastic Industry supplied multiple 15-cubic-meter flexible digesters to participating households.

Each system was designed with reinforced polymer membranes suitable for outdoor agricultural environments.

Typical technical characteristics included:

Membrane structure

PVC-coated polyester composite material

Material thickness

Approximately 1.0 mm

Fabric density

Around 1000 g/m²

Seam construction

Thermal fusion welding ensuring continuous gas-tight seams

Gas storage pressure

Low-pressure operating range suitable for household biogas stoves

The digesters were designed as modular units that could be transported folded and assembled on-site.

Installation in the Village Environment

Installation sites were selected near livestock housing areas to simplify manure collection.

The installation procedure included:

• Preparing a compacted soil base
• Positioning the digester body
• Installing inlet and outlet pipes
• Connecting gas pipelines to household kitchens

Because the digesters were flexible, no deep excavation was required. Partial soil covering helped stabilize the units and protect them from direct sunlight.

This approach reduced installation complexity compared with masonry digesters.

Operational Practices

After installation, households were trained in basic digester operation.

Typical feedstock preparation involved mixing pig manure with water before introducing the slurry into the inlet pipe.

Daily feeding amounts generally ranged between:

• 20–30 kg of manure slurry per household

Under Vietnam’s tropical climate conditions, average temperatures of 25–30°C supported natural anaerobic fermentation.

The hydraulic retention time of the digesters was approximately 25–35 days, depending on feedstock composition.

Operational Outcomes

Over the initial months of operation, households reported several practical changes.

Improved waste handling

Manure was now directed into the digester rather than accumulating in open pits.

Cooking fuel generation

Biogas produced by the digesters was used in kitchen stoves for daily cooking activities.

Organic fertilizer production

The digested slurry was applied to vegetable gardens and rice fields.

These outcomes demonstrated how small modular digesters can support waste treatment and energy production at the household level.

Industry Perspective

Village-scale projects provide valuable insights into the real-world performance of decentralized biogas systems. In densely populated rural communities, flexible digesters offer an installation approach that avoids complex civil construction while maintaining the essential conditions for anaerobic fermentation.

The experience from this Vietnamese village project illustrates how manufacturers such as Henan Zonghai Plastic Industry Co., Ltd. are contributing equipment solutions that align with the practical requirements of Southeast Asian farming environments.