Wastewater Treatment Process with Controlled Dissolved Oxygen
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Solution Overview
Problem
Conventional wastewater treatment processes are not optimized to produce the best quality of treated water, as they often involve separate steps and do not efficiently control dissolved oxygen concentrations to maximize the breakdown of contaminants by aerobic and anaerobic bacterial processes.
Innovation Solution
A process involving a contact step where wastewater contacts bacteria retained on a support surface with controlled dissolved oxygen levels, an aeration step with reduced oxygen to promote endospore-forming bacteria growth, and a sedimentation step, with sludge recycling to enhance contaminant breakdown and settling characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional separate-step treatment processes are used, then the treatment process is simple to operate, but the quality of treated water is not optimized and contaminant removal efficiency is insufficient
Solution Approach 1:
The patent combines multiple treatment functions (aerobic degradation, anaerobic processes, endospore-forming bacteria growth promotion, and sedimentation) into a single integrated bioreactor system. The support surface structure enables simultaneous occurrence of different biological processes within one reactor, achieving high-quality treated water through combined mechanisms rather than separate sequential steps
Solution Approach 2:
The bioreactor is segmented into distinct functional zones: an aerobic zone for carbonaceous matter degradation, an anoxic zone for nitrogen removal, and a sedimentation zone for solid-liquid separation. The support surface creates micro-environments with different oxygen concentrations, enabling simultaneous aerobic and anaerobic processes within the same reactor volume
2Productivity
If dissolved oxygen concentration is not controlled, then the operation is simple, but the breakdown of contaminants by aerobic and anaerobic bacterial processes is not maximized
Solution Approach 1:
The support surface structure creates local zones with different dissolved oxygen concentrations within the same reactor. The three-dimensional support surface provides aerobic environments on its surface while creating anoxic zones in the surrounding liquid, enabling simultaneous aerobic degradation and anaerobic processes without requiring external oxygen control mechanisms
Solution Approach 2:
The system self-regulates dissolved oxygen distribution through the natural architecture of the support surface and flow patterns. Oxygen is consumed locally by aerobic bacteria on the support surface, automatically creating gradient zones that promote both aerobic and anaerobic processes without external intervention or complex control systems
3Manufacturing precision
If specific types of microorganisms are not utilized, then the treatment process is simpler, but the removal efficiency of contaminants and improvement of settling characteristics is reduced
Solution Approach 1:
The system creates specific environmental parameters (low dissolved oxygen concentration zones, presence of support surface) that select for and promote the growth of endospore-forming bacteria. These parameter changes enable the microorganism population to adapt and develop enhanced settling characteristics and contaminant removal capabilities naturally within the reactor
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 process achieves exceptional removal efficiencies for carbonaceous matter, total nitrogen, and total phosphorus, producing high-quality treated water with low suspended solids and improved bacterial populations, as demonstrated by a full-scale treatment plant survey.
Implementation Method 1
an aerobic step, where carbonaceous matter is biologically oxidised to carbon dioxide and water
Implementation Method 2
an anoxic step, where nitrates (and nitrites) are reduced to molecular nitrogen (in the absence of oxygen and in the presence of carbonaceous matter)
Implementation Method 3
an aeration step, wherein gas is passed through wastewater that has passed through the contact step
Implementation Method 4
a sedimentation step, wherein wastewater that has passed through the aeration step is substantially separated into treated water and sludge
Data Source
AI summary
The present invention relates to a process for treating wastewater that includes the steps of: —a contact step, wherein wastewater contacts bacteria retained on a support surface and the dissolved oxygen concentration of the wastewater is maintained at 2.0 mg/l or less; an aeration step, wherein gas is passed through wastewater that has passed through the contact step and the dissolved oxygen concentration of the wastewater is reduced as the wastewater passes through the aeration step; a sedimentation step, wherein wastewater that has passed through the aeration step is substantially separated into treated water and sludge; and a sludge recycling step, wherein sludge from the sedimentation step is passed to the contact step. The invention also relates to a processing unit on which the aforementioned process may be operated.