Container House Rainwater Collection

Rainwater collection in container houses can be achieved through processes such as roof water collection, diversion, filtration, storage, and utilization, with the core being the construction of an integrated system and the rational design of parameters for each module.

Rainwater Collection System Design

For rainwater collection in container houses, the roof should serve as the core water collection area. The inclined structure of the roof panels (a recommended slope of ≥5%) is utilized to guide rainwater towards a circular collection trough. A drainage outlet is set at the bottom of the collection trough, and rainwater is conveyed to the treatment system through PVC drainage pipes (with a diameter of ≥10 cm). For example, in the patented design of China Minmetals 23rd Construction Co., Ltd., the roof panels are inclined towards the collection trough to ensure efficient rainwater convergence.

Rainwater Treatment System Design

The treatment system should include sedimentation and filtration processes. Rainwater enters the sedimentation tank through the drainage pipes, where suspended solids and large particulate impurities (such as silt and leaves) are removed by gravity sedimentation. The sedimented rainwater then flows into the filtration tank, which is filled with filtration media such as quartz sand and activated carbon to further remove fine particles and organic matter. If the water is for non-potable use, deep purification can be omitted; if it needs to meet the standards for domestic water, additional modules such as ultraviolet disinfection or chlorine tablet disinfection should be installed.

Rainwater Storage and Utilization Design

In the storage process, the capacity of the water storage tank should be matched according to the water demand of the container house. For example, a 100 m² roof can collect 1 ton of water under a rainfall of 10 mm. If the water is used for irrigation and toilet flushing, a 2-3 m³ PE water storage tank will suffice. The water storage tank should be made of food-grade materials, equipped with a float valve to control the water level, a mosquito net installed on the top, and a drainage valve and an overflow pipe (with a diameter greater than that of the inlet pipe by 30%) at the bottom. In the utilization process, the treated water can be conveyed to water consumption points such as irrigation sprinklers and toilet flushing tanks through gravity flow or a constant-pressure water pump.

Key Parameters and Optimization

• Water Collection Efficiency: The roof area and the average annual rainfall determine the capacity of the water storage tank, and a 20%-30% redundancy should be reserved to cope with extreme rainfall events.
• Anti-pollution Design: For primary filtration, a 20-40 mesh stainless steel screen is used to intercept large particles. The water storage tank should be sealed and cleaned regularly (it is recommended to dredge the sedimentation tank every quarter).
• Safety Redundancy: The overflow pipe should be connected to the municipal drainage system or an infiltration well to avoid waterlogging. Maintenance access points should be set every 20 meters along the diversion pipes for easy maintenance.