Membrane Bioreactor Zero Sludge Discharge

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Solution Overview

Problem

Conventional wastewater treatment methods fail to effectively remove small particle sediments, leading to filter system obstructions and incomplete sludge removal, as they rely primarily on gravity and do not address the decomposition of inorganic silt and organic sludge.

Innovation Solution

A membrane bioreactor system is employed, inoculated with silicate-solubilising bacteria, which aerates the reaction vessel and membrane separation system to control dissolved oxygen concentrations, allowing the bacteria to decompose inorganic silt and organic sludge into dissolvable substances, thereby preventing sludge discharge.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If gravity-based sedimentation is used to remove silt, then large particles are removed, but small particle sediments remain and cause filter system obstruction

Engineering Contradiction:
Improveremoval of large particlesVSAvoidfilter system operation
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The patent replaces the mechanical gravity-based sedimentation system with a biological treatment system using silicate-solubilising bacteria. These bacteria chemically dissolve inorganic silt particles, converting them into soluble forms that can pass through membranes without causing obstruction, thereby eliminating the filter clogging problem while maintaining particle removal effectiveness.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the chemical state of inorganic silt from insoluble particles to soluble silicate ions through bacterial action. This parameter change in solubility allows the silt to be removed in dissolved form rather than as particulate matter, preventing filter system obstruction while achieving complete silt removal.

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If conventional sedimentation methods are used, then removal process is simple, but inorganic silt and organic sludge are not completely decomposed

Engineering Contradiction:
Improvesimplicity of removal processVSAvoiddecomposition of inorganic silt and organic sludge
Core Design Contradiction:
Ease of manufactureVSLoss of substance

Solution Approach 1:

The patent introduces silicate-solubilising bacteria as an intermediary biological agent that facilitates the decomposition of inorganic silt and organic sludge. These bacteria act as a mediator between the wastewater and the decomposition process, enabling complete breakdown of contaminants while maintaining a relatively simple treatment system structure.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent employs controlled dissolved oxygen parameters (0-2 mg/L around membrane, 0-1 mg/L in reaction vessel) to optimize bacterial metabolism and decomposition efficiency. By adjusting these chemical parameters, the system achieves complete decomposition of inorganic silt and organic sludge while maintaining operational simplicity.

Inventive Principle:
Principle #35Parameter changes

3Loss of substance

If membrane bioreactor with zero discharge is used, then sludge discharge is eliminated, but dissolved oxygen control is complex

Engineering Contradiction:
Improvesludge dischargeVSAvoiddissolved oxygen control
Core Design Contradiction:
Loss of substanceVSDevice complexity

Solution Approach 1:

The patent applies different dissolved oxygen control strategies to different spatial zones: 0-2 mg/L around the membrane separation system and 0-1 mg/L in the reaction vessel excluding the membrane system. This localized quality control optimizes bacterial activity and membrane performance separately, achieving zero sludge discharge while managing complexity through zoned management.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent implements dissolved oxygen monitoring and control feedback mechanisms to maintain optimal oxygen levels for silicate-solubilising bacteria. By continuously measuring and adjusting oxygen concentrations in different zones, the system achieves zero sludge discharge while managing the complexity of oxygen control through automated feedback regulation.

Inventive Principle:
Principle #23Feedback

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

The method achieves complete decomposition of inorganic silt and organic sludge, ensuring zero sludge discharge and meeting urban recycling water quality standards, while being compatible with other biochemical treatment processes.

Implementation Method 1

the silicate-solubilising bacteria quickly grows and become predominant in the system in the reaction region, silica is converted into dissolvable silicate ions

Methodology Applied
Scientific EffectBiological decomposition: Decomposition (biological)

Implementation Method 2

The inorganic silt and organic sludge in the wastewater are gradually decomposed into gas and dissolvable substances in the process of the proliferation and metabolism of the microbes

Methodology Applied
Scientific EffectMicrobial metabolism: Fermentation

Implementation Method 3

aerating the membrane separation system and the reaction vessel to control a dissolved oxygen concentration of the wastewater around the membrane separation system to be greater than 0 and smaller than 2 mg/L

Methodology Applied
Scientific EffectAeration: Aeration

Implementation Method 4

silica is converted into dissolvable silicate ions which are able to penetrate the membrane separation system and is carried away by the water

Methodology Applied
Scientific EffectMembrane filtration: Semipermeable Membrane

Implementation Method 5

A conventional method for removing silt from the wastewater is mainly dependent on the gravity of the silt

Methodology Applied
Scientific EffectGravity: Gravitation

Data Source

PatentEP3344584B1Method of wastewater treatment with zero discharge of sludge
Publication Date: 2021.06.30 JIANGXI JDL ENVIRONMENTAL PROTECTION CO LTD
  • EP3344584B1 patent drawingFigure 1~2

AI summary

A method for wastewater treatment with zero discharge of sludge is provided, which including: a) providing a membrane bioreactor system comprising a membrane separation system (1) and a reaction vessel (2); and b) aerating the membrane separation system (1) and the reaction vessel (2) to control a dissolved oxygen concentration around the membrane separation system (1) to be greater than 0 and smaller than 2 mg/L and the dissolved oxygen concentration in the reaction vessel (2) excluding the membrane separation system (1) to be greater than 0 and smaller than 1 mg/L. A wastewater treatment system with zero discharge of sludge includes a membrane bioreactor system, and the membrane bioreactor system includes a reaction vessel (2), a membrane separation system (1), a water production system, and an aeration system.