Project Overview

In rural areas of northwest China, where winter temperatures plummet to -28°C and permafrost reaches depths of 2.0 meters, a specialized wastewater treatment project addresses daily water volumes of 2.0–20.0 tons (2.0–20.0t/d). Characterized by scattered residential layouts and limited technical support, these regions require robust, low-maintenance solutions to overcome geographical and climatic challenges.

Challenge: Extreme Cold, Scattered Habitation, and Maintenance Gaps

1. Harsh Climatic Conditions: Subzero temperatures and deep permafrost pose significant risks to traditional wastewater systems, which often freeze or fail in extreme cold.

2. Decentralized Living: Villagers reside in isolated clusters, making centralized sewer networks costly and impractical to install.

3. Technical Isolation: Remote locations lack permanent professional maintenance staff, necessitating systems that operate independently with minimal upkeep.

Solution: BioFilter Series for Cold-Climate Resilience

Technical Features

• Extreme Cold Resistance: HDPE tanks with 14mm wall thickness and 2.8 meters of soil cover resist freezing, maintaining stable treatment performance even at -28°C.

• Off-Grid & Maintenance-Free: Nano-porous bio-enzyme media enables aerobic digestion without electricity or chemical inputs, eliminating the need for technical personnel.

• Modular Scalability: Units are matched to local water demands:

• BioFilter-2000: Suits small households.

• BioFilter-5000/7000: Ideal for mid-sized villages.

• BioFilter-10000: Handles larger community clusters.

• High Load-Bearing Capacity: The tanks’ structural design withstands heavy soil pressure from deep soil cover, ensuring long-term durability.

  
  

Operational Impact

1. Seasonal Treatment Efficiency

• Summer Resource Reuse: Treated effluent is reused for irrigating orchards and vegetable fields, improving soil moisture and reducing freshwater consumption.

• Winter Compliant Discharge: In freezing months, the system produces effluent that meets local discharge standards (GB 18918-2002), safely returning to natural water bodies without pollution.

2. Cold-Climate Performance Metrics

• BOD/COD Removal: >90% reduction, ensuring water quality for agricultural use and environmental protection.

• Freeze Resistance: The buried design and HDPE material prevent tank cracking, with microbial activity remaining stable via natural insulation.

3. Cost-Effectiveness & Community Benefits

• Energy Savings: Zero electricity use cuts operational costs by 60–70% compared to powered systems.

• Low Labor Demand: Annual inspections by local staff suffice, eliminating reliance on specialized technicians.

• Environmental Stewardship: The system prevents untreated sewage from contaminating groundwater and surface water, supporting northwest China’s ecological conservation efforts.

Conclusion: A Cold-Climate Blueprint for Rural China