Algae Aggregation via Aging and Pressurized Filtration
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Solution Overview
Problem
Current methods for harvesting algae from aqueous environments, such as dissolved air flotation, are inefficient due to algae re-entering the water and are sensitive to environmental fluctuations, posing challenges in concentration and processing.
Innovation Solution
Aging the algae in an unaerated environment for at least 90 hours followed by pressurized filtration through a filter medium at pressures between 25 psig and 1500 psig to form crystalline or quasi-crystalline aggregates, which are too large to clog the filter and can be efficiently separated from water.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If dissolved air flotation is used to separate algae from aqueous environment, then algae can be concentrated at the surface, but the skimming process is inefficient and algae fall back into the bulk environment
Solution Approach 1:
The patent applies preliminary action by pre-coagulating algae cells before filtration. The coagulation step causes algae to aggregate into larger flocs that are more easily captured by the filter medium, preventing them from passing through or falling back into the bulk environment. This pre-treatment enhances the overall separation efficiency and productivity.
Solution Approach 2:
The patent introduces an intermediary substance (coagulant) that mediates between the algae cells and the filtration process. The coagulant acts as a bridge that causes dispersed algae cells to aggregate, making them more amenable to filtration and reducing their tendency to re-enter the bulk water after separation.
2Quantity of substance
If conventional filtration is used to separate algae, then separation can be achieved, but filtration rates are slow and filter media clog easily
Solution Approach 1:
The patent applies preliminary action by pre-coagulating algae cells into larger aggregates before they reach the filter medium. This pre-treatment prevents individual cells from clogging filter pores, maintaining high filtration rates throughout the process while achieving complete separation.
Solution Approach 2:
The patent changes the physical parameters of algae by transforming them from individual dispersed cells into larger coagulated aggregates. This parameter change in size and structure allows the algae to be more easily filtered without clogging the medium, thereby increasing filtration rate and productivity.
3Adaptability or versatility
If algae are present in low concentration in aqueous environment, then algae can be grown in ponds, but separation from water becomes difficult and requires extensive processing
Solution Approach 1:
The patent applies preliminary action by implementing a coagulation step before filtration. This pre-treatment transforms low-concentration dispersed algae into concentrated aggregates, simplifying the subsequent separation process and reducing the complexity of equipment and operations required.
Solution Approach 2:
The patent changes the concentration parameter of algae by using coagulation to transform low-concentration dispersed cells into high-concentration aggregates. This parameter change simplifies the separation process and reduces the complexity of the overall system while maintaining the advantage of pond-based cultivation.
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 rates and reduces the tendency for algae to re-enter the water, enhancing the separation efficiency and reducing the need for further processing of wastewater.
Implementation Method 1
aging an aqueous feed containing algae in an unaerated environment for a period of at least about 90 hours
Implementation Method 2
filtering the aqueous feed through a filter medium at a pressure of about 25 psig (about 170 kPag) to about 1500 psig (about 10.3 MPag)
Data Source
AI summary
Methods are provided for separating algae from an aqueous environment. An aqueous feed containing algae can be aged for a period of at least about 90 hours without purging or other aeration. The aging of the aqueous feed can result in formation of aggregated algae, which can then be filtered under pressure. Due to the larger size of the algae aggregates, the pressurized filtration can reduce/minimize the tendency to clog the filter, as the algae aggregates can generally be too large to fit within the pores of the filter. The filter can preferably be located at the bottom of the vessel holding the aqueous feed. This can assist in allowing the algae to remain in a cake above the filter, as opposed to having the algae dissolve back into the aqueous feed.