Microalgae Harvesting via Hollow Fiber Filtration
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Solution Overview
Problem
Current methods for harvesting microalgae are inefficient, requiring high capital and operating costs, and often involve the use of coagulants that can contaminate the product and increase costs, with limited ability to achieve high concentration and bioavailability of the final product.
Innovation Solution
An apparatus and method that uses a series or parallel combination of separation and concentration stages, including inside-out hollow fiber filtration and cross-flow filtration cassettes, to achieve a final microalgae concentration of at least 6-8 wt % in a solid-containing fraction, allowing for efficient dewatering and concentration while maintaining bioactivity and bioavailability, and enabling recycling of the liquid fraction for nutrient reuse.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional centrifuges or dissolved air floatation systems are used for algae harvesting, then algae can be separated from liquid medium, but capital and operating costs increase and capture efficiency remains low
Solution Approach 1:
The harvesting system is divided into multiple sequential stages: initial centrifugation to remove bulk algae, followed by tangential flow filtration to concentrate remaining algae to high cell densities. This segmentation allows each stage to optimize for its specific function, achieving both high separation effectiveness and improved overall productivity
Solution Approach 2:
Tangential flow filtration serves as an intermediary process between traditional centrifugation and final algae product recovery. This intermediate step concentrates algae that were missed by centrifugation without requiring additional chemical additives, thereby improving capture efficiency while maintaining cost-effectiveness
2Reliability
If dissolved air floatation systems with coagulants are used, then algae can be harvested, but operating costs increase and product contamination occurs
Solution Approach 1:
The system extracts and removes the harmful coagulant step entirely from the harvesting process. By using purely physical separation methods (centrifugation followed by tangential flow filtration), algae are concentrated without chemical additives, eliminating product contamination while maintaining harvesting effectiveness
Solution Approach 2:
The system replaces expensive chemical coagulants with disposable filtration membranes in the tangential flow filtration stage. While membranes require replacement, they eliminate ongoing chemical costs and avoid product contamination, providing a cost-effective and clean harvesting approach
3Quantity of substance
If high concentration of microalgae is achieved through traditional methods, then more algae can be recovered, but additional processing is required which drives up costs
Solution Approach 1:
Tangential flow filtration operates continuously to concentrate algae from the centrifuge effluent to high cell densities without interruption. This continuous concentration process eliminates the need for batch processing and additional separation steps, achieving high algae concentration while maintaining processing efficiency and avoiding cost increases
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 solution achieves higher efficiency in microalgae concentration with lower operational costs, improved product quality, and reduced storage requirements, while maintaining algae bioavailability and bioactivity, and allows for the reuse of nutrients, thereby reducing the need for new inputs in cultivation.
Implementation Method 1
a hollow fiber filtration apparatus, wherein a microalgae-containing liquid medium is filtered through the hollow fiber filtration apparatus
Data Source
AI summary
An apparatus and method of separating microalgae from a liquid source material, wherein the apparatus and method permit the efficient achievement of a high concentration of microalgae in a final solid-containing fraction.