Biomass Filter Aid for Sludge Dewatering and Hydrothermal Conversion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current wastewater treatment methods, particularly those involving filtration and hydrothermal liquefaction, face inefficiencies due to the difficulty in separating particulate matter from water, leading to high energy consumption, costly additional cleaning steps, and challenges in dewatering sewage sludge beyond 10% dry matter content.
Innovation Solution
The use of biomass filter aids prepared by extrusion of lignocellulosic feedstocks with 30-75% dry matter content to filter sewage sludge, allowing for subsequent hydrothermal liquefaction without a drying step, thereby enhancing oil yields and reducing process costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional filtration methods are used to separate particulate matter from liquid streams, then separation can be achieved, but filtration becomes slow and energy intensive with high equipment requirements
Solution Approach 1:
The patent introduces a filter aid as an intermediary substance that facilitates the separation process. The filter aid forms a porous structure that allows liquid to pass through while retaining particulate matter, thereby accelerating filtration without requiring excessive energy input or complex equipment
2Productivity
If filter aids are used to improve filtration efficiency, then separation performance increases, but the cost significantly increases and the amount of material to be handled increases
Solution Approach 1:
The patent changes the physical parameters of the filter aid by controlling its moisture content (30-75% dry matter) and particle size distribution. This optimization allows the filter aid to form an effective filtering structure with reduced material quantity, improving efficiency while minimizing the amount of material that needs to be handled and disposed of
3Quantity of substance
If sewage sludge is filtered to remove water, then dewatering can be achieved, but it becomes extremely difficult to dewater beyond 10% dry matter content
Solution Approach 1:
The filter aid acts as a mediator that interacts with the sludge particles and water differently than the particles interact with each other. The filter aid creates a three-phase system (filter aid, sludge, water) where water can be efficiently removed while maintaining higher solids content in the filter cake, overcoming the 10% dry matter barrier
4Device complexity
If filter cakes with high water content are produced, then filtration can be simplified, but the cost for drying the filter cakes increases significantly
Solution Approach 1:
The patent optimizes the filter aid parameters (moisture content, particle size, composition) to produce a filter cake with balanced water content that is low enough to minimize drying costs but high enough to maintain filtration simplicity. The filter aid's physical properties are tuned to retain water in the filtrate rather than in the cake
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 method significantly improves filtration efficiency, reduces energy consumption, and increases bio-oil yields by utilizing the spent filter aid as a substrate in hydrothermal liquefaction, overcoming the limitations of traditional filter aids and drying processes.
Implementation Method 1
filtering particulate matter from an aqueous stream, using biomass as a filter aid
Implementation Method 2
using the spent filter aid with collected sewage sludge as a substrate for hydrothermal liquefaction
Data Source
AI summary
The present invention relates to a method of wastewater treatment in which a filter aid prepared by extrusion of freshly harvested wet lignocellulosic feedstocks or by extrusion of wet lignocellulosic feedstocks having dry matter content 30-75% (w/w) is used to collect sewage sludge and the combined spent filter aid with collected sewage sludge is used for hydrothermal conversion.