Anaerobic-Aerobic Wastewater Treatment System for Pathogen Reduction
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Solution Overview
Problem
Current wastewater treatment technologies, particularly anaerobic digestion systems, face challenges with the production of digestate, which has high levels of pathogens, nitrates, and phosphorus, making it hazardous for discharge and requiring costly storage and soil management, and existing methods to reduce digestate volume are energy-intensive and costly.
Innovation Solution
A system comprising stirred anaerobic and aerobic reactors with recycling communication, a discharge basin, and a gas collector, allowing for repeated mixing and settling cycles to treat livestock or poultry waste, producing safe water and soil amendment without chemical additives, and utilizing biogas for energy generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If anaerobic digestion technology is used to produce electricity from organic waste, then energy production is improved, but digestate with high levels of pathogens, nitrates, and phosphorus is formed which requires costly storage and treatment
Solution Approach 1:
The system segments the treatment process into distinct anaerobic and aerobic reaction stages. The anaerobic reactor produces biogas for energy, while the subsequent aerobic reactor treats the digestate to reduce contamination. This segmentation allows simultaneous energy production and harmful factor reduction through separate functional zones.
Solution Approach 2:
The aerobic reactor serves as an intermediary treatment stage between the anaerobic digestion process and final discharge. It mediates the transformation of harmful digestate components by introducing aerobic conditions that reduce pathogen levels and transform nitrogen compounds, enabling safe discharge or agricultural use.
2Adaptability or versatility
If digestate is dispersed in arable lands to utilize nutrient levels, then nutrient recycling is improved, but runoff during rainy seasons increases pollution risk and requires 4-8 months storage
Solution Approach 1:
The system performs preliminary aerobic treatment of digestate before discharge or land application. This preliminary action reduces pathogen levels and transforms nitrogen compounds in advance, eliminating the need for prolonged storage and reducing runoff pollution risks when digestate is eventually applied to land.
Solution Approach 2:
The aerobic reactor changes the chemical and biological parameters of digestate by introducing oxygen, raising oxidation-reduction potential, and transforming ammonia to nitrate. These parameter changes reduce harmful effects and enable safe land application without extended storage requirements.
3Quantity of substance
If mechanical separation and evaporation are used to reduce digestate volume, then volume reduction is improved, but additional chemicals and energy are required increasing treatment costs
Solution Approach 1:
The aerobic reactor utilizes naturally occurring aerobic microorganisms to treat and concentrate digestate solids without requiring external chemicals or high-energy input. The system self-services by leveraging biological oxidation processes that occur naturally when oxygen is introduced, reducing volume through water evaporation and solid concentration.
Solution Approach 2:
The system converts the harmful aerobic oxidation that would normally increase odor and pathogen issues into a beneficial process. By controlled aerobic treatment, the system reduces digestate volume through natural evaporation and solidification while simultaneously reducing harmful contaminants, transforming a potential problem into a volume reduction solution.
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 system effectively reduces organic matter, nitrogen, and phosphorus levels in wastewater, producing safe water for discharge and a high-quality soil amendment, while reducing capital and operating expenses and environmental impact, and generating energy from biogas.
Implementation Method 1
During anaerobic digestion, organic matter is broken down gradually using a complex system of bacteria until biogas is produced
Implementation Method 2
The effluent from the anaerobic reactors is transferred to an aerobic reactor where aerobic oxidation takes place
Implementation Method 3
utilizing biogas for energy generation
Data Source
AI summary
A system for treating organic feedstock, particularly livestock or poultry wastewater. The system employs combined anaerobic and aerobic digestion for converting the wastewater into safe water, fertilizer, and energy, wherein sequencing batch reactors (i.e. ASBR and SBR) are used for the digestion process.