Inflatable Photobioreactor for Algae Harvesting
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Solution Overview
Problem
The large-scale production of algae is hindered by challenges in harvesting and dewatering due to their small size and dilute concentrations, as well as the risk of contamination from predators and invasive species in wastewater-based cultivation systems, which increases costs and environmental concerns.
Innovation Solution
The use of selectively inflatable photobioreactors with porous membrane filters that control the position and orientation for controlled dewatering and harvesting, allowing for the separation of algae from contaminants and utilizing wastewater nutrients while preventing invasive species entry, with gas-generated pressure used to inflate floats for dewatering and harvesting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If algae are cultivated in dilute concentrations in open systems, then algae growth is promoted, but harvesting and dewatering become problematic and expensive
Solution Approach 1:
The system divides the cultivation process into separate functional zones: a growth zone where algae cultivate in dilute concentrations, and a harvesting zone where concentrated algae are collected. This segmentation allows each zone to optimize for its specific function without compromising the other.
Solution Approach 2:
A porous partition acts as an intermediary between the growth zone and harvesting zone, allowing nutrients and water to pass through while retaining algae cells. This mediator enables the transition from dilute growth conditions to concentrated harvest conditions without direct mechanical intervention in the growth zone.
2Ease of manufacture
If wastewater is used as growth media, then nutrients and carbon dioxide are provided for free, but the risk of introducing predators, grazers, and invasive species increases
Solution Approach 1:
The porous partition serves as a protective intermediary that allows beneficial substances (nutrients, CO2, water) to pass from the wastewater medium to the algae while blocking harmful organisms (predators, grazers, invasive species). This enables safe utilization of wastewater resources.
Solution Approach 2:
The porous partition functions as a selective barrier film that distinguishes between useful substances to be retained or passed and harmful substances to be excluded, providing protection while maintaining resource availability.
3Productivity
If open raceway ponds are used for cultivation, then large-scale production is enabled, but contamination by environmental contaminants is easily introduced
Solution Approach 1:
The large-scale system is segmented into multiple enclosed modules, each with its own porous partition. This modular segmentation maintains the scalability of large-scale production while isolating each unit from environmental contaminants through the protective barrier function of the partitions.
4Reliability
If synthetic growth media is sterilized before addition to closed algal culture, then contamination is prevented, but substantial cost is added to production
Solution Approach 1:
The system uses the porous partition to provide automatic, continuous sterilization and protection without requiring external intervention. The physical barrier self-service function replaces the need for expensive chemical or thermal sterilization processes while maintaining equivalent or superior protection effectiveness.
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 enables efficient dewatering and harvesting of algae, reducing production costs and environmental impact by utilizing wastewater nutrients while maintaining culture purity, resulting in a self-sustaining and cost-effective algae production system.
Implementation Method 1
porous membrane filters that enable the passive transport of constituents (i.e., nutrients and gases) from a growth medium
Implementation Method 2
gas-generated pressure used to inflate floats for dewatering and harvesting
Implementation Method 3
selectively inflatable photobioreactors with porous membrane filters that control the position and orientation
Data Source
AI summary
In one embodiment, an algae cultivation system includes a basin that contains a liquid and a photobioreactor at least partially immersed in the liquid of the basin, the photobioreactor comprising a closed container including multiple panels that together define an interior space in which algae can be cultivated, at least one of the panels being transparent, the photobioreactor further comprising an inflatable float associated with the container that can be filled with a gas to change one or both of the position and orientation of the container within the liquid.