Train Wastewater Treatment Reduces Corrosive Salt Buildup

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Solution Overview

Problem

The treatment of sanitary wastewater in trains poses a challenge for aluminum alloy components, as existing methods fail to effectively remove corrosive salts, leading to potential damage from chloride ions and copper, which can cause corrosion.

Innovation Solution

A method involving a bioreactor system with phase separation and vacuum evaporation, where organic acids or mineral acids are added to adjust pH, reducing ammonia output and concentrating inorganic salts, thereby minimizing corrosive effects on aluminum alloys.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a coating is applied to aluminum train bodies to protect from corrosion, then corrosion resistance is improved, but the coating can be damaged by stone strikes creating cracks that enable intensive contact of corrosive liquid with the body

Engineering Contradiction:
Improvecorrosion resistanceVSAvoidcontact of corrosive liquid with body
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The harmful inorganic components (salts, copper, chloride ions) are extracted from the wastewater through bioreactor treatment and phase separation, removing the corrosive agents before the water is discharged or reused on the train. This eliminates the need for protective coatings against corrosion.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The bioreactor system converts the harmful corrosive wastewater into a beneficial purified water resource that can be reused for toilet flushing and sink supply, while the concentrated salts are disposed of safely. The harmful corrosive properties are transformed into a water recycling system.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

2Loss of substance

If conventional bioreactor treatment is used to clean wastewater, then organic components are reduced, but inorganic components such as copper and chloride ions remain causing corrosion

Engineering Contradiction:
Improveorganic components reductionVSAvoidinorganic components causing corrosion
Core Design Contradiction:
Loss of substanceVSObject-affected harmful factors

Solution Approach 1:

The treatment process is segmented into distinct stages: first the bioreactor removes organic components, then a phase separation system divides the wastewater into organic-rich and inorganic-rich phases, allowing selective removal of corrosive inorganic ions. This multi-stage segmentation addresses both organic and inorganic pollution separately.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system changes physical parameters through vacuum evaporation and phase separation, transforming the wastewater from a homogeneous corrosive mixture into separated phases where inorganic salts are concentrated and removed, fundamentally altering the chemical composition and corrosiveness of the treated water.

Inventive Principle:
Principle #35Parameter changes

3Object-affected harmful factors

If wastewater volume is reduced through treatment, then corrosive effects are minimized, but treatment system complexity increases

Engineering Contradiction:
Improvecorrosive effectsVSAvoidtreatment system complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The treated water serves multiple functions: it can be discharged safely, reused for toilet flushing, or supplied to sinks. The phase separation system handles multiple separation tasks, and the condensate serves both as purified water and as a medium for heat exchange in the vacuum evaporator.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The system uses its own waste heat from the bioreactor and condensation process to drive the vacuum evaporator, creating a self-sustaining thermal cycle. The phase separation and concentration processes occur automatically based on density and solubility differences without requiring additional energy input.

Inventive Principle:
Principle #25Self-service

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 significantly reduces the volume of corrosive wastewater, achieving a nearly ammonia-free distillate with reduced copper and chloride content, which can be safely reused or disposed of, protecting aluminum train components from corrosion.

Implementation Method 1

degradation of the solids content in a first compartment under predominantly aerobic conditions

Methodology Applied
Scientific EffectAerobic degradation: Aerobic Digestion

Implementation Method 2

forwarding the liquid portion into a second compartment in which a degradation takes place under predominantly anoxic conditions

Methodology Applied
Scientific EffectAnoxic degradation: Anaerobic Digestion

Implementation Method 3

c) at least partial phase separation of the partially purified wastewater in the conditioning system, d) gaining a liquid proportion and a fixed component of the at least partially purified wastewater

Methodology Applied
Scientific EffectVacuum evaporation: Vacuum Distillation

Data Source

PatentEP3464188B1Method and device for treating sanitary wastewater in trains
Publication Date: 2021.10.27 AKW AV PROTEC HLDG GMBH
  • EP3464188B1 patent drawingFigure 1
  • EP3464188B1 patent drawingFigure 2
  • EP3464188B1 patent drawing

AI summary

The invention relates to a method for treating wastewater containing organic matter and/or wet waste containing organic matter, in particular for treating sanitary wastewater (15) in trains. According to the invention, the method comprises the following steps: a) cleaning the wastewater containing matter and/or the wet waste containing organic matter, in particular the sanitary wastewater (15) in trains, in a bioreactor (20), b) feeding the wastewater (24) at least partially purified in the bioreactor (20) into a conditioning system (30), c) at least partially separating phases of the partially purified wastewater (24) in the conditioning system (30), d) obtaining a liquid fraction and a solid fraction of the at least partially purified wastewater (24).