Upstream Denitrification Reactors in Recirculating Aquaculture
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional recirculating aquaculture systems face challenges with high water consumption, excessive nitrogenous waste discharge, and toxicity issues due to imbalanced water chemistries, which are exacerbated by the placement of denitrification reactors downstream of aerobic nitrification, leading to inefficiencies and environmental concerns.
Innovation Solution
A novel arrangement where anaerobic denitrification reactors are positioned upstream of aerobic nitrification reactors, with a mechanical filtration system to remove particulates, allowing for efficient conversion of nitrogenous waste to nitrogen gas, thereby reducing nitrate-nitrogen concentrations and mitigating harmful water chemistries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If denitrification reactors are positioned downstream of aerobic nitrification (conventional arrangement), then nitrate can be removed from the system, but water chemistry becomes imbalanced leading to toxic accumulation of nitrite and hydrogen sulfide
Solution Approach 1:
The patent inverts the conventional arrangement by placing denitrification reactors upstream of aerobic nitrification reactors. This reversal prevents the accumulation of toxic intermediates (nitrite and hydrogen sulfide) by ensuring that denitrification occurs on fresh influent before nitrification processes, thereby eliminating the harmful chemical imbalances that occur in traditional downstream configurations.
Solution Approach 2:
The denitrification reactors perform preliminary nitrate removal on incoming wastewater before the water enters the aerobic nitrification stage. This preliminary action reduces the nitrogen load that subsequent nitrification must handle, preventing overflow of nitrogenous compounds that would otherwise accumulate and create toxic conditions in the system.
2Quantity of substance
If water exchange is used to remove nitrate-nitrogen from recirculating aquaculture systems, then nitrate levels can be reduced, but excessive water consumption occurs which is harmful to the environment
Solution Approach 1:
The system uses self-service biological denitrification processes where indigenous microorganisms in the denitrification reactors naturally convert nitrate-nitrogen to nitrogen gas. This eliminates the need for external water exchange to remove nitrate, as the system autonomously handles nitrate removal through biological conversion, thereby conserving water resources while maintaining water quality.
Solution Approach 2:
The patent changes the chemical parameter of nitrate-nitrogen concentration through biological denitrification, converting it from a dissolved nutrient form to gaseous nitrogen that can be safely discharged. This parameter transformation allows the system to remove excess nitrogen without the need for large-volume water exchanges, thus resolving the contradiction between nitrate removal and water conservation.
3Productivity
If high protein feeds are used to increase fish growth rates, then profitability increases, but nitrogenous waste generation increases significantly requiring more extensive treatment
Solution Approach 1:
The patent converts the harmful nitrogenous waste products (ammonia and nitrate) generated from high-protein feeding into beneficial outcomes. The denitrification reactors transform toxic nitrate into harmless nitrogen gas, while the overall system design allows for higher stocking densities and growth rates by efficiently managing the waste burden, thereby turning the curse of high waste generation into an opportunity for intensified sustainable production.
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 configuration enhances water conservation, reduces nitrogenous waste discharge, and improves the safety and sustainability of aquatic species by effectively managing nitrate-nitrogen levels and water chemistry, addressing the limitations of traditional systems.
Implementation Method 1
anaerobic denitrification reactors positioned upstream of aerobic nitrification... efficient conversion of nitrogenous waste to nitrogen gas, thereby reducing nitrate-nitrogen concentrations
Implementation Method 2
aerobic nitrification... ammonia is oxidized to nitrite (NO2−) by autotrophic bacteria in an aerobic biofilter. However, the nitrite generated is also toxic, so a second bacterium is required to oxidize the nitrite to nitrate (NO3−)
Implementation Method 3
with a mechanical filtration system to remove particulates
Data Source
AI summary
The present invention relates to a novel arrangement of denitrification reactors for removal of nitrate compounds in a recirculating aquaculture system. The novel arrangement of an aquaculture system of the present invention includes positioning one or more anaerobic denitrification reactors upstream of aerobic nitrification and degassing processes. One aspect of the present invention includes a flow of aqueous medium from aquatic species rearing tanks towards one or more denitrification reactors. Another aspect of the present invention includes flow of aqueous medium from aquatic species rearing tanks to a solids removing filter or mechanical filtration means for removal of solid waste matter or biomass prior to flow of aqueous medium towards one or more denitrification reactors. In a sequence of components comprising a system of the present invention, treated and denitrified aqueous medium exiting one or more denitrification reactors is directed towards a solids removing filter wherein treated and denitrified aqueous medium combines with untreated aqueous medium. Combined untreated aqueous medium and denitrified aqueous medium exits a solids removing filter and is directed towards an aerobic nitrification unit. Aqueous medium exiting the aerobic nitrification unit is degassed and oxygenated and returned to aquatic species rearing tanks. A system of the present invention which utilizes denitrification reactors positioned upstream of aerobic nitrification has advantages over existing aquaculture systems which use denitrification in reduction of nitrate concentrations. This results in greater mitigation of water chemistries and compounds which are harmful to aquatic species and more efficient use and conservation of water resources.