Rotating Cloth Filter with Sludge Recirculation for Wastewater
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current wastewater treatment methods, particularly primary filtration by gravity separation, face inefficiencies due to variable particle size distributions in wastewater, leading to low capture rates of particulate pollution and high operating costs from chemical conditioning, which results in uncertain purification performance and excessive sludge production.
Innovation Solution
A device and method for wastewater treatment that includes primary filtration by gravity separation on a rotating cloth with a recirculation system to enhance particle retention, utilizing a hydrocyclone for size-based separation and turbidity probes for control, allowing for increased filtration efficiency without additional chemical reagents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If chemical coagulation and flocculation are used to improve particle retention, then removal efficiency increases, but operating costs increase and sludge production increases
Solution Approach 1:
The system uses the effluent's own particles to form a filter cake that performs the filtration, eliminating the need for external coagulants and flocculants. The filter cake acts as a self-formed filtering medium that captures particles based on size exclusion rather than chemical aggregation.
Solution Approach 2:
The patent extracts and removes the chemical conditioning step from the treatment process, relying instead on physical filtration through a rotating drum screen with a self-formed cake layer. This eliminates reagent addition while maintaining effective particle removal.
2Duration of action of stationary object
If a coarse mesh screen is used for filtration, then the filter cloth durability increases, but particle capture efficiency decreases for small particles
Solution Approach 1:
The system performs preliminary concentration of particles on the screen surface to form a filter cake layer before actual filtration begins. This pre-formed cake layer provides the fine filtration capability needed for small particles, while the robust underlying screen structure maintains durability.
Solution Approach 2:
The filtration system combines a robust coarse mesh screen structure with a fine particle filter cake layer. The composite structure leverages the mechanical strength of the coarse screen and the fine filtration capability of the particle cake, achieving both durability and high capture efficiency.
3Reliability
If direct filtration through fine cloth is used, then particle removal efficiency increases, but the filter cloth is more fragile and prone to tearing
Solution Approach 1:
The system forms a protective filter cake layer on the screen surface before subjecting the filtration medium to abrasive effluent flow. This preliminary cake formation protects the underlying fine filtration structure from direct mechanical damage while maintaining high particle removal efficiency.
Solution Approach 2:
Instead of using a fragile fine mesh cloth directly, the system creates a functional copy of fine filtration capability through the self-formed particle cake layer. This cake layer replicates the fine filtration effect without the mechanical weakness of fine woven fabrics.
4Adaptability or versatility
If the particle size distribution in effluent varies, then treatment performance becomes unpredictable, but adjusting the mesh size requires changing the filtration system
Solution Approach 1:
The system dynamically adapts to varying particle size distributions by allowing the filter cake to self-adjust its structure and density based on the incoming effluent characteristics. The rotating drum screen maintains constant operation while the cake layer automatically optimizes for different particle compositions.
Solution Approach 2:
The system changes the operational parameters of the filtration process by varying the rotation speed, flow rate, and cake formation conditions in response to different effluent characteristics. These parameter adjustments optimize particle capture without requiring physical changes to the screen mesh size.
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 approach increases the retention of small particles, enhances filtration performance, and reduces operating costs by eliminating the need for chemical conditioning, while maintaining control over treatment efficiency and minimizing sludge production.
Implementation Method 1
primary filtration by gravity separation on a rotating cloth
Implementation Method 2
at least one recirculation device intended to recirculate at least a part of the sludge from the second stream back to the inlet of the filtration device
Implementation Method 3
utilizing a hydrocyclone for size-based separation
Implementation Method 4
turbidity probes for control
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The invention relates to a device for treating (50) an effluent (8) composed of liquid and solid particles such as to obtain a treated effluent, comprising a filtering device (11) using gravity separation on a rotating canvas having an inlet (12) for receiving the effluent (8) to be treated and a first (13) and second (14) outlet, the filtering device (11) being intended for separating the effluent (8) into a first (17) and a second (18) flow, the second flow (18) comprising sludge containing solid particles, the first flow (17) leaving the filtering device (11) through the first outlet (13), the second flow (18) leaving the filtering device (11) through the second outlet (18), and at least one recirculation device (19) for recirculating at least a portion of the sludge from the second flow (18) to the inlet (12) of the filtering device (11), said second outlet being connected to the at least one recirculation device (19). The invention also relates to a method for treating an effluent.