Micro-algae Cultivation Using Partially Purified Industrial Wastewater

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Solution Overview

Problem

Conventional micro-algae cultivation methods require fresh or saltwater with added nutrients, limiting the use of industrial wastewater due to toxicity from pollutants like chlorides, sulphates, and heavy metals, which hinders growth despite nitrogenated compounds being present.

Innovation Solution

Utilizing partially purified industrial wastewater from oil refineries as a nitrogen source for micro-algae cultivation, integrating it with phosphorous nutrients to achieve comparable productivity to traditional methods, and employing optimized growth conditions such as reduced nitrogen and phosphorous concentrations, and adjusted pH levels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If industrial wastewater is used as culture medium for micro-algae cultivation, then nitrogenated nutrients are available for growth, but toxicity from pollutants (chlorides, sulphates, heavy metals) hinders micro-algae proliferation

Engineering Contradiction:
Improvenitrogenated nutrientsVSAvoidtoxicity from pollutants
Core Design Contradiction:
Quantity of substanceVSObject-affected harmful factors

Solution Approach 1:

The wastewater treatment process is segmented into stages: primary treatment removes suspended solids, secondary treatment performs biological oxidation of organic compounds, and tertiary treatment eliminates nitrogenated and phosphorated compounds. This segmentation allows progressive purification while retaining beneficial nitrogenated nutrients at optimal concentrations (0.1-0.5 mg/l) for micro-algae cultivation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention converts harmful industrial wastewater containing pollutants into a beneficial culture medium. By carefully controlling the treatment process, the wastewater is purified to remove excessive toxins while preserving nitrogenated compounds that serve as nutrients for micro-algae, thus transforming a harmful substance into a useful resource for biomass production.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

2Productivity

If traditional nutrient solutions are used for micro-algae cultivation, then optimal growth conditions are achieved, but cost and resource efficiency are reduced

Engineering Contradiction:
Improvemicro-algae proliferation rateVSAvoidnutrient consumption
Core Design Contradiction:
ProductivityVSLoss of substance

Solution Approach 1:

The system uses partially purified industrial wastewater that already contains nitrogenated nutrients from industrial processes. Instead of adding all nutrients externally, the micro-algae cultivate themselves using the nitrogenated compounds already present in the wastewater, reducing the need for external nutrient supplementation and lowering operational costs.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The invention changes the parameters of the culture medium by using real industrial wastewater with specific characteristics (pH 6.5-7.5, nitrogenated compounds at 0.1-0.5 mg/l) instead of standardized nutrient solutions. This parameter optimization allows maintaining high productivity while reducing nutrient consumption and costs.

Inventive Principle:
Principle #35Parameter changes

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 process allows for effective proliferation and biomass production of micro-algae strains like Scenedesmus sp. and Tetraselmis su. in industrial wastewater, matching productivity with traditional nutrient solutions, while enabling the recycling and reuse of treated wastewater.

Implementation Method 1

The gaseous phase is bubbled through the liquid mass, through perforated ducts immersed in the growth basin, in order to have the maximum availability of CO2 for the micro-alga

Methodology Applied
Scientific EffectPhotosynthesis: Photosynthesis

Data Source

PatentUS7977085B2Process for the cultivation of micro-algae
Publication Date: 2011.07.12 ENI SPA

AI summary

Process for the cultivation of micro-algae comprising the planting of an algal strain in an aqueous environment and the growth process, under solar irradiation, by continuously feeding a gaseous stream essentially consisting of carbon dioxide and a stream of nutrients based on nitrogen, consisting of wastewater from industrial plants, coming from secondary treatment processes.