Microalgae Cultivation with EM Bacteria and NOx Denitration
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Solution Overview
Problem
Current methods for cultivating microalgae face challenges such as contamination from harmful bacteria, high costs due to the need for sterilization, and inefficiencies in using industrial waste gases for denitration, particularly with NOx being poorly soluble in water and requiring costly nitrogen fertilizers.
Innovation Solution
A process that combines microalgae cultivation with denitration of industrial waste gases using an aqueous solution of nitric acid/hydrogen peroxide, incorporating EM bacteria to inhibit harmful bacteria and recycle nitrogen sources, thereby reducing costs and improving biomass productivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If an open system is used to cultivate microalgae, then the operation cost is reduced, but the risk of bacterial contamination increases
Solution Approach 1:
EM bacteria are introduced as intermediary organisms that produce antibacterial substances to suppress harmful bacteria. These EM bacteria act as mediators between the open system environment and the microalgae culture, creating a protective biological barrier that allows open system operation without sterilization while preventing bacterial contamination
Solution Approach 2:
The system uses biological self-regulation where EM bacteria naturally produce antibacterial effects and compete with harmful bacteria for resources. This self-service mechanism maintains culture purity without requiring external sterilization interventions, enabling cost-effective open system cultivation
2Reliability
If a closed cultivation system with sterilization is used, then bacterial contamination is prevented, but the operation cost increases
Solution Approach 1:
EM bacteria serve as biological intermediaries that provide continuous antibacterial protection through their metabolic activities. This living barrier replaces the need for expensive sterilization infrastructure and operations, achieving contamination prevention through biological means rather than thermal or chemical sterilization
Solution Approach 2:
The patent converts the potential harm of open system bacterial contamination into a benefit by using EM bacteria's natural antibacterial properties. The very biological activity that could potentially harm the culture is harnessed to protect against harmful bacteria, eliminating sterilization costs while maintaining culture purity
3Ease of manufacture
If NOx from industrial waste gas is directly absorbed in water, then the absorption cost is reduced, but the absorption efficiency is low due to poor solubility
Solution Approach 1:
The patent changes the chemical parameters of the absorption solution by adding oxidizing agents (peroxide, permanganate, or chlorate) to water. This parameter modification transforms the absorption mechanism from simple physical dissolution to chemical oxidation-absorption, dramatically improving NOx absorption efficiency while maintaining low operational costs
Solution Approach 2:
Strong oxidizing agents are introduced to accelerate the oxidation of NO to NO2, which then absorbs more readily in the alkaline solution. This oxidation enhancement overcomes the poor solubility of NO in water, achieving high absorption efficiency without increasing infrastructure costs
4Productivity
If nitrogenous fertilizer is added to microalgae cultivation, then the growth rate is improved, but the operation cost increases
Solution Approach 1:
The patent recovers nitrogen from industrial waste gas (a discarded pollutant) and converts it into a usable nitrogen source for microalgae cultivation. This recovery process replaces expensive commercial nitrogenous fertilizers, reducing operational costs while maintaining or improving microalgae growth rates through the use of recovered nitrogen compounds
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 approach enhances microalgae biomass productivity, avoids the need for sterilization, and effectively utilizes NOx from industrial waste gases as a nitrogen source, reducing environmental pollution and operational costs.
Implementation Method 1
incorporating EM bacteria to inhibit harmful bacteria
Implementation Method 2
denitration of industrial waste gases using an aqueous solution of nitric acid/hydrogen peroxide
Implementation Method 3
converts the optical energy into a chemical energy of carbohydrates, such as fat or starch, by effective photosynthesis
Data Source
AI summary
The present invention provides a process of cultivating microalgae and a joint method of same jointed with denitration. During the microalgae cultivation, EM bacteria is added into the microalgae suspension. In the nutrient stream for cultivating microalgae, at least one of the nitrogen source, phosphorus source and carbon source is provided in the form of a nutrient salt. During the cultivation, the pH of the microalgae suspension is adjusted with nitric acid and/or nitrous acid. The joint method includes (1) a step of cultivating microalgae; (2) a separation step of separating a microalgae suspension obtained from step (1) into a wet microalgae (microalgae biomass) and a residual cultivation solution; and (3) a NOx absorbing/immobilizing step of denitrating an industrial waste gas with the residual cultivation solution obtained from step (2). The nutrient stream absorbed with NOx obtained from step (3) is used to provide nitrogen source to the microalgae cultivation of step (1).