Slide 1

Concept of viscous heating to reinvent the toiletMD.WALIUL ISLAM

Research GroupGary L. FoutchAJ Johannes Jagdeep T. PodichettyDavid VanMason Reichard

Our conceptViscosity &Viscous Heating

Most ViscousLeast Viscous

Viscosity Is The Resistance To Fluid Flow

A Viscous Substance Becomes Heated When Layer Deformation Is Allowed To Occur -This is called Viscous Heating

Viscous Heating Is An Effective Mechanism To Treat Human Waste

Fully Instrumented Reactor

How Viscous Is Human Feces???

Feed Preparation

Effect of Hold up time on Temperature Temperature Rise With Holdup Time @ ConstantPressure 100 psigRPM 1800Spacing 0.75

Effect of RPM on Temperature RiseTemperature Rise With RPM @ ConstantPressure 100 psigHoldup Time 3min Spacing 0.75 mm

Effect of Spacing on Temperature Rise

Temperature Rise With Spacing @ConstantPressure 100 psigHoldup Time 3min RPM 1209

Summary of Experimental ResultTemperature Rises AsRPM IncreasesHold Time IncreasesGap Spacing Decreases

The Highest Temperature Rise up to Date 190C

Parasite Egg Destruction In Baboon FecesRPMSpacingTemperature%killmmC%9131.2042939130.75519918000.758695

Energy Balance

Kinetic Energy of The Shaft + Heat Gain By The Product + Heat Lost To The Environment+System LossEnergy for The Plunger+Energy of The Motor =

Energy Balance (contd)

Power versus Time for No Load and Load Conditions at 100 psig, 0.75mm spacing and 1800 rpm

Energy Balance(contd)Kinetic Energy Of The Shaft(Negligible)+ Heat Gain By The Product + Heat Lost To The environment

Energy of Plunger (Negligible)+Energy of The Motor Under Load(242 KJ)-Energy of The Motor No load (171 KJ)

=

(71 KJ)

Energy Balance (contd)

Assuming An Insulated System

System Efficiency,

=

=

=29.6%

Heat Gain By The Product+ Heat Lost to The EnvironmentWork Done By The Motor Under Load Condition71 KJ243KJ0

Constant Spacing Variable RPMCheapPortable

Our Attempt For Modification

RPMSpacingHoldup TimeTemperaturemmsecondsC10001180411000127047

Result With Modified Reactor

ConclusionExperimentation Confirmed That Viscous Heating By Extrusion Is Effective

Shear Force And Viscous Heat Are Sufficient To Kill Diseases Causing Parasites

Maintaining Sufficient Feed Viscosity Will Be A Requirement Of Effective Operation

RecommendationsCombination With Other Treatment TechnologiesAddition of Paper Or Biomass wastes Recycle Of The Drier Solid Wastes To Achieve Required ViscosityConstruction Materials Focusing On Heat Transfer Properties and InsulationScreening Or Segregation Is RequiredSanitized Solids Could Be Used As Nutrient In Agricultural Applications

Thank You!!!

Simulation Run In COMSOL Multiphysics

AssumptionDensity1000 kg/m3 Viscosity5 Pa.sThermal Conductivity 0.03 W/(m.K)Heat Capacity4186 J/(kg.k)

Inlet Velocity 0.002 m/s @ 500 rpm

Effect of Clearance

Effect of Clearance @ Length = 0.1 m, Semi-Angle = 21.8

Effect of Length

Effect of length @ Semi-Angle = 21.8 & Clearance = 0.001m

Effect of Semi Angle

Effect of Semi-Angle @ Length = 1m, Clearance = 0.001m