Granular Biomass Production via Polymer Flocculation
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Solution Overview
Problem
The high cost and logistical challenges of procuring and transporting granular biomass for seeding and reseeding anaerobic and aerobic wastewater treatment systems, due to limited supply and slow biomass growth, necessitate the development of a method to produce granular biomass locally and efficiently.
Innovation Solution
A granulator system that continuously produces granular biomass on-site using digested sewage sludge or activated sludge, employing cationic and anionic polymers, along with inert additives, to optimize granule formation and stabilization, reducing the need for external seed biomass.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If granular biomass is procured from existing treatment plants for seeding, then the treatment system can be started or reseeded, but the costs for procurement and transportation are high and prohibitive
Solution Approach 1:
The treatment system produces its own granular biomass seed on-site using the granulator system, eliminating the need to purchase and transport expensive seed biomass from external sources. The system uses readily available sludge materials and converts them into functional granular biomass through controlled granulation processes.
Solution Approach 2:
The invention changes the physical and chemical parameters of the sludge material through controlled addition of cationic polymers, anionic polymers, and inorganic additives, transforming it into granular biomass with appropriate settling properties and biological activity for reactor seeding.
2Reliability
If granular biomass is transported from existing treatment plants, then seed biomass can be introduced to the new system, but transportation costs are prohibitive due to long distances and high water content
Solution Approach 1:
The system generates its own seed biomass locally, eliminating the energy-intensive transportation process entirely. The granulator system processes sludge on-site into granular form, avoiding the need to transport bulky, water-heavy biomass over long distances.
Solution Approach 2:
The invention transforms the physical state and composition of the sludge material through chemical additives and controlled granulation, creating dense granular biomass with improved settling characteristics that can be used immediately without transportation.
3Manufacturing precision
If cationic polymer chemicals are continuously added to enhance granulation, then granule formation is improved, but the long term dosing of expensive chemicals increases costs
Solution Approach 1:
The system establishes continuous granulation through the sustained presence of cationic polymers in the sludge stream, ensuring consistent granule formation. The polymers remain active throughout the granulation process, continuously facilitating particle aggregation and granule development.
Solution Approach 2:
The invention creates composite granular biomass by combining sludge material with cationic polymers, anionic polymers, and inorganic additives. This composite approach enhances granule structure and settling properties while distributing chemical costs across multiple components rather than relying on a single expensive additive.
4Manufacturing precision
If batch wise production of granular biomass is used, then granular biomass can be produced from anaerobically digested sewage sludge, but the volume required to be handled is too large for practical purposes
Solution Approach 1:
The invention transitions from batch processing to continuous granulation, where sludge material is continuously fed into the granulator system and granular biomass is continuously produced. This continuous operation eliminates the need to handle and store large volumes of material that would be required for batch processing, reducing equipment size and operational complexity.
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 system significantly reduces the costs associated with biomass procurement and transportation, enabling rapid start-up and reseeding of treatment systems while maintaining biological activity and settling properties comparable to naturally formed granular biomass.
Implementation Method 1
granulation of sewage sludge can be enhanced in situ in working granular biomass reactors through the continuous addition of cationic polymer chemicals
Implementation Method 2
a second polymer is a high molecular weight anionic silica sol which neutralizes the surface charge on the granular biomass produced in the first mixing tank and fixes and stabilizes the granular biomass formed
Implementation Method 3
A mixer (4) secures the optimal energy input regime for polymer dispersion and granulation to initiate under the flocculation effect of the polymer
Implementation Method 4
granulated biomass is retained by virtue of the good settleability of such biomass and the design of special separators internal to the reactors that can effectively separate and retain such granular biomass
Data Source
AI summary
The invention is directed to a process for producing granular biomass suitable for starting up or reseeding of biological treatment systems, which process comprises contacting a suitable flocculent sludge in a first mixing step with at least one cationic polymer, and subsequently contacting the mixture of sludge and cationic polymer thus obtained with at least one anionic polymer in a second mixing step, wherein the process is continuous and a hydraulic retention time in the first mixing step is maintained of 0.5-30 minutes, more preferably 2-7 minutes and wherein the hydraulic retention time in the second mixing step is maintained at 0.5-30 minutes, more preferably 2-7 minutes.