Partially Hydrolyzed Biosolids Viscosity Reduction

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Solution Overview

Problem

Conventional methods for processing biosolids cake in wastewater treatment plants are costly and inefficient, with only a limited proportion of the biosolids being utilized due to significant inert fractions remaining after partial hydrolysis, which hampers biogas yields and requires expensive chemical additions.

Innovation Solution

A method involving the storage of partially hydrolyzed biosolids under anaerobic conditions with continued hydrolysis and digestion in a storage vessel, reducing viscosity and increasing the digestibility of biosolids, allowing for enhanced biogas production without the need for high energy inputs or extensive mixing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If biosolids cake is subjected to conventional anaerobic digestion, then pathogen load is reduced and solids are stabilized, but biogas yields remain low due to poor mixing performance and limited digestibility of polymeric substances

Engineering Contradiction:

Improvebiogas yieldsVSAvoiddigestibility of biosolids

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The biosolids cake is subjected to hydrolysis treatment before anaerobic digestion to break down polymeric substances into more digestible forms. This preliminary action enhances the digestibility of the biosolids, allowing anaerobic microorganisms to more effectively convert organic matter into biogas, thereby resolving the contradiction between low biogas yields and limited digestibility

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

Alkali substances are introduced as an intermediary to facilitate hydrolysis of the biosolids cake. The alkali promotes breakdown of complex polymeric substances, making them more accessible to anaerobic digestion. This intermediary substance enables improved biogas production without requiring extensive mechanical mixing, thus resolving the contradiction between productivity and reliability

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of operation

If biosolids cake viscosity is reduced through hydrolysis, then handling and pumping become easier, but significant inert fractions remain that hamper biogas yields

Engineering Contradiction:

Improvehandling and pumping of biosolidsVSAvoidbiogas yields

Core Design Contradiction:

Ease of operationVSProductivity

Solution Approach 1:

The hydrolysis process is optimized by controlling parameters such as temperature, pH, and retention time to achieve sufficient breakdown of polymeric substances for improved handling, while avoiding over-hydrolysis that would leave excessive inert fractions. This parameter optimization resolves the contradiction between ease of operation and biogas productivity

Inventive Principle:

Principle #35Parameter changes

3Ease of operation

If conventional thermal hydrolysis is used to reduce viscosity, then biosolids become more pumpable, but the process requires high energy inputs and significant capital costs

Engineering Contradiction:

Improvepumpability of biosolidsVSAvoidenergy input for hydrolysis

Core Design Contradiction:

Ease of operationVSUse of energy by moving object

Solution Approach 1:

The invention employs chemical hydrolysis using alkali substances as a lower-cost alternative to conventional thermal hydrolysis. This chemical approach achieves sufficient viscosity reduction and pumpability improvement without requiring the high energy inputs and expensive equipment of thermal processes, resolving the contradiction between ease of operation and energy consumption

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

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 method increases the utilization of biosolids in anaerobic digesters, reduces biosolids disposal costs, and enhances biogas yields while eliminating pathogens, making the processed biosolids easily pumpable and suitable for use within the treatment plant without additional transportation or handling.

Implementation Method 1

the input mixture is subjected to anaerobic conditions and hydrolysis over a predetermined time period, to form the output mixture having an output mixture viscosity that is less than the input mixture viscosity

Methodology Applied

Scientific EffectHydrolysis: Hydrolysis

Implementation Method 2

Anaerobic digestion of sewage sludge occurs when oxygen is limited. A proportion of the volatile solids or organics is biologically converted to biogas (e.g., methane).

Methodology Applied

Scientific EffectAnaerobic digestion: Anaerobic Digestion

Data Source

PatentUS11420890B2Method of treatment of partially hydrolyzed biosolids

Publication Date: 2022.08.23 LYSTEK INT

AI summary

A method of processing enhanced biosolids from a wastewater treatment plant to produce an output mixture. The method includes providing one or more volumes of an input mixture that has an input mixture viscosity. The input mixture includes the enhanced biosolids, which have been subjected to shear forces and mixed in a mixing vessel. The enhanced biosolids are partially hydrolyzed biosolids with an input solids content between 4% and 16% by weight of the input mixture. The input mixture also includes sufficient process liquid to result in the output mixture having an output solids content between 3% and 13% by weight of the output mixture. The input mixture is stored in a storage vessel in which the input mixture is subjected to anaerobic conditions and hydrolysis over a predetermined tie period, to form the output mixture having an output mixture viscosity that is less than the input mixture viscosity.