Two-Stage Multimedia Biological Filtration for Wastewater Head Loss Reduction
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Solution Overview
Problem
Conventional wastewater treatment systems face challenges in achieving high water quality and minimizing head loss, particularly in two-stage multimedia-single medium biological filtration processes, which often result in increased head loss and operational inefficiencies due to frequent backwashing and solid loading.
Innovation Solution
A two-stage multimedia-multimedia biological filtration process is implemented, with a consecutive arrangement of media sizes in large-middle-middle large-small order, and operation under anoxic and aerobic conditions in each stage, injecting carbon sources and coagulants to minimize head loss and enhance treatment efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a two-stage single-medium biological filtration process is used, then water quality is improved, but head loss increases and requires frequent backwashing
Solution Approach 1:
The patent applies composite materials by using multiple types of media (anthracite, sand, gravel) with different properties in a layered configuration. The anthracite layer captures organic matter while the sand and gravel layers provide mechanical filtration and support, creating a composite filtration system that reduces head loss compared to single-medium systems while maintaining high water quality standards.
Solution Approach 2:
The patent segments the filtration system into multiple stages with different media types and particle sizes. The first stage uses anthracite for organic matter removal, while the second stage uses sand and gravel for mechanical filtration. This segmentation allows each layer to optimize its function, reducing overall head loss while achieving superior water quality.
2Productivity
If solid loading is increased to reduce plant site area, then treatment efficiency is improved, but head loss increases rapidly
Solution Approach 1:
The composite media structure with anthracite, sand, and gravel layers distributes the solid loading across different materials with varying porosity and flow characteristics. This composite approach allows higher solid loading rates while maintaining lower head loss compared to single-medium systems, as each layer handles different aspects of the filtration process.
Solution Approach 2:
The patent applies local quality by assigning different media properties to different layers based on their specific functions. The anthracite layer has larger pores for organic matter capture, while the sand and gravel layers have smaller pores for mechanical filtration. This localized optimization allows the system to handle higher solid loads without proportional increases in head loss.
3Reliability
If frequent backwashing is performed to maintain filtration efficiency, then treatment performance is maintained, but operation shutdown and water loss increase
Solution Approach 1:
The composite media structure reduces the frequency of backwashing required compared to single-medium systems. The layered configuration with anthracite, sand, and gravel creates a more resilient filtration system that maintains performance longer between backwashing cycles, reducing operational shutdown time and water loss.
Solution Approach 2:
By segmenting the filtration into multiple stages with different media, the system distributes the filtration burden across layers, preventing any single layer from becoming quickly clogged. This segmentation extends the operational cycle between backwashing events, reducing time loss and improving overall system reliability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration effectively removes nitrogen, phosphorous, and organic materials, reducing head loss and extending filtering time, resulting in superior water quality with reduced solid loading and operational costs, achieving BOD and SS levels below 3.0 mg/L and T-N and T-P below 0.1 mg/L.
Implementation Method 1
a submerged medium used in the lower part of the first stage for multimedia biological filtration process
Implementation Method 2
biological filtration process
Implementation Method 3
injecting carbon sources and coagulants to minimize head loss and enhance treatment efficiency
Data Source
AI summary
A wastewater treatment apparatus of the present invention is configured to biologically filter wastewater through multimedia by consecutively performing two stages (the first and second stages) for a multimedia biological filtration process. A carbon source and coagulant are respectively injected during the first and second multimedia biological filtration processes. The first stage multimedia biological filtration process is carried out in anoxic conditions and the second stage multimedia biological filtration process is carried out in aerobic conditions. The media for the first and second stage biological filtration processes are arranged in large-middle-middle large-small size. Thus, the present invention can secure excellent treated water while minimizing loss of water-head by maximizing reflux capability of solids.