How does the fermentation bio-reactor achieve deep and synergistic removal of nitrogen and phosphorus from rural wastewater through integrated design?
Publish Time: 2025-11-26
With the deepening of China's rural revitalization strategy, rural domestic wastewater treatment has become a key link in improving the living environment and protecting the aquatic ecological environment. However, rural wastewater generally suffers from large fluctuations in water quality, insufficient carbon sources, high nitrogen and phosphorus concentrations, and weak operation and maintenance capabilities of treatment facilities, posing severe challenges to traditional wastewater treatment technologies. Against this backdrop, an integrated fermentation bio-reactor, combining fermentation units with biological nitrogen and phosphorus removal functions, has emerged. Through ingenious structural and process coupling, it achieves deep and synergistic removal of nitrogen and phosphorus pollutants.
1. Integrated Structure: Fusion of Spatial Integration and Process Optimization
The fermentation bio-reactor adopts a highly integrated modular design, integrating the anaerobic fermentation zone, anoxic denitrification zone, aerobic nitrification/phosphorus uptake zone, and sedimentation separation unit into a single tank. This "one tank, multiple functions" layout not only significantly saves floor space but also avoids the energy consumption and management complexity caused by pipeline connections and pumping in traditional multi-stage processes. More importantly, the internal flow-guiding structure enables hydraulic interconnection and material circulation between functional zones, allowing wastewater to sequentially undergo different oxidation-reduction environments without external power, creating ideal conditions for the stepwise transformation and removal of nitrogen and phosphorus.
2. Endogenous Carbon Source Regulation: Solving the Problem of Low Carbon-to-Nitrogen Ratio in Rural Wastewater
Rural wastewater generally has a low carbon-to-nitrogen ratio, severely restricting the denitrification process. Traditional processes often require the addition of external carbon sources such as sodium acetate, increasing operating costs. The core innovation of this reactor lies in the pre-anaerobic fermentation unit—utilizing primary sludge or part of the influent under anaerobic conditions to hydrolyze and produce acid, generating an endogenous carbon source mainly composed of volatile fatty acids. These VFAs are then introduced into the anoxic zone, acting as efficient electron donors to drive denitrifying bacteria to reduce nitrates to nitrogen gas; simultaneously, in the alternating anaerobic-aerobic environment, polyphosphate-accumulating bacteria can excessively absorb phosphorus and store it in the form of polyphosphates within their cells, ultimately achieving permanent phosphorus removal through sludge discharge. This "self-production and self-use" carbon source recycling mechanism significantly improves the system's adaptability to low-carbon wastewater.
3. Microbial Synergistic Metabolism: Constructing a Highly Efficient Nitrogen and Phosphorus Removal Microecology
The integrated design not only optimizes the physical process but also promotes the synergistic symbiosis of functional microorganisms. In the anaerobic zone, fermenting bacteria decompose organic matter to produce VFAs, while simultaneously providing energy for phosphorus release by polyphosphate-accumulating bacteria. Upon entering the anoxic zone, denitrifying bacteria utilize VFAs to complete nitrogen removal. In the aerobic zone, ammonia-oxidizing bacteria convert ammonia nitrogen into nitrate, while polyphosphate-accumulating bacteria simultaneously perform superphosphate uptake. Notably, some novel microbial communities, such as denitrifying polyphosphate-accumulating bacteria, may simultaneously complete denitrification and phosphorus uptake under anoxic conditions, further enhancing nitrogen and phosphorus removal efficiency. This multi-level, multi-pathway microbial metabolic network enables the system to maintain stable and efficient purification performance even under low or shock loads.
4. Low-Consumption Intelligent Operation and Maintenance: Meeting Rural Needs
Addressing the lack of professional operation and maintenance personnel in rural areas, this equipment is typically equipped with intelligent modules such as automatic sludge discharge, intermittent aeration control, and liquid level sensing, enabling "minimal" or even "unattended" operation. Meanwhile, the integrated structure reduces the number of external pipes and valves, lowering the risk of blockage and leakage.
In summary, the integrated fermentation bio-reactor, through structural integration, endogenous carbon source regulation, enhanced microbial function, and intelligent operation and maintenance design, has successfully constructed a highly efficient nitrogen and phosphorus removal technology pathway suitable for the characteristics of rural wastewater in China. It not only solves the pain points of traditional processes such as insufficient carbon sources, large footprint, and difficult operation and maintenance, but also embodies the green governance concept of "resource internal circulation, low energy consumption, and high-quality effluent," providing a replicable and scalable innovative paradigm for rural water environment governance.
