Puxin concrete mould system

Submitted by Nick Chase on
Last changed on 02 Aug, 2016 - 08:43

The Puxin system was developed by Chinese company Puxin to succeed the GCC. The system uses steal molds to create a ring system in which concrete could be poured. With the Puxin molds digesters in the sizes of 4, 6 or 10m³ could be build. Average building time is about 4 to 7 days. 

It could be divided in 5 parts:

  1. concrete base
  2. concrete lower ring (needed for 4, 6 and 10 m³)
  3. concrete higher ring (additional if pouring a 10 m³ digester
  4. concrete neck
  5. fiber glass gas holder sitting inside the neck

The actual size makes it a perfect fit for farms and communities. Due to fiber glass dome in combination with a concrete neck the gas can be lightly pressured. Therefore the Puxin digester does not need a gas pump.


Watch the dry build of a Puxin digester to get an an idea of how to build a Puxin digester


  • Puxin gas holder
  • Puxin molds
  • Cements: 36 bags (50 kgs bag)( total 1800 kgs) OR 50 bags (80 lbs bag)( total 4000 lbs) .
  • Sand: Same amount as Cement .
  • Gravel: 1st- About 300 lbs of 1” Gravel for foundation.
  • 2nd Small size Gravel: in same amount of Cement.
  • Iron rod for rebar:  Using 7 sheets of rebar (7’×17’) OR 5-7 rods (1/4” diameter , 39 feet length ).
  • Wires: About  2 kg 
  • Sealant (inlet & outlet walls paint ): 20 liters of waterproof acrylic paint , and about 15 liters of tar paint .
  • Bricks: Between 600 bricks .
  • Labors: 2 trained and 5 untrained workers 
  • Backhoe:  The hole must be at least 15’ × 15’
  • Wood mold for concrete slab 11’×11’
  • PVC pipe 20’ × 5” & 20’ × 2”

Tools and Machines

  • Cement mixer
  • Cement vibrator
  • Electric generator
  • Hand tools


  • Heating system 1st- using the compost to heat the biodigester we need 300 yard of ½” PEX tube ( 200 yard of  for compost coil and 100 yard inside the digester coil or used other heat exchanger inside the digester ) and small water pump.
  • 2nd- using solar water heater we need solar water heater about 500 liter capacity , and 100 yard inside the digester coil or used other heat exchanger inside the digester ) and small water pump. 
  • 3rd- using propane water heater or biogas water heater we need water heater run by gases ( depend on what we can provide ) , and  100 yard inside the digester coil or used other heat exchanger inside the digester ) and small water pump.


Due to the flexible system digesters of different size (4,6,10m³) could be build. The gas holder makes it possible to pressurize the gas a little. The digester could be build below ground using the earth as insulation. 


In order to build the digester a lot of labor is needed. The initial costs for the molds are pretty high. As they need to be shipped from China import tax has to be paid in Europe. The gas holder is a very unique part produced out of fiber glass. In order to have a sustainable shipping costs to material ratio many domes need to be bought on the initial molds purchase. When importing gas appliances like stoves, or water heaters into Europe all appliances need a CE labeling. Currently Puxin doesn't provide that labeling. Though those gas appliances couldn't be imported into Europe. As steel molds are used a separation agent needs to be applied. 



Download:  Puxin build / fact manual Puxin family size digester fact sheet