9 Physics principles: waves 2. Ultrasound sciencePhysics principles: wavesBall movement over time describes a wave.In terms of physics a wave is a perturbation that propagates through a medium.
10 Physics principles: waves 2. Ultrasound sciencePhysics principles: wavesAA complete oscillation takes a T time (Period)TimeFor one complete oscillation T, the frequence f is the number of oscillations per second, termed as f = T-1a = A·sen(ωt) // ω = 2π·f
11 2. Ultrasound science Acoustic waves: types Sound is a wave where excited magnitude is pressure (vertical axis is A = P).Ultrasound is a type of acoustic wave where the frequence is higher than 20 kHz (human limit).In the same way as sound, ultrasound needs a medium to propagate (wastewater or sludge).20 Hz20 kHzInfrasoundAcousticUltrasound
12 2. Ultrasound science Ultrasonic waves Successive pressures (+) and (-) cause particles movement and wave propagation.(A) is the amplitude and determines power (P), (P = E/t, E = mω2A2/2) and intensity I (I = P/S), measured in (W/cm2).
13 Ultrasonic Cavitation 2. Ultrasound scienceUltrasonic CavitationWhen pressures (+) and (-) take place under frequences about 20 kHz and intensities between 25 and 50 W/cm2, the medium breaks and produces small bubbles.This phenomenon is known as Ultrasonic Cavitation.
14 Creation and implosion of the cavitation bubbles 2. Ultrasound scienceCreation and implosion of the cavitation bubblesUltrasonic cavitation is the process consisting of bubble creation, growth, and collapse by implosion.Cavitation bubbles can reach internal temperatures about 5,000 ºC and pressures about 500 bar.These extreme conditions are controlled and used to disintegrate biomass → DUMO Ultralyzer.
15 3. Ultrasound engineering How can we produce ultrasonic waves?Piezoelectricity: a pressure wave pushes on the piezoelectric crystal inducing internal crystal vibration, which causes electrical voltage at the crystal surface. This phenomenon is reversible and used to generate ultrasound waves.ElectricalenergyPiezoelectrical crystalUltrasonic wave
16 3. Ultrasound engineering DUMO Ultralyzer parts: GENERATORTransform the inlet electric signal (240 Vac, 50 Hz) into a sinusoidal wave (900 Vrms at 20 kHz).Able to adapt automatically to all conditions in order to maintain constant the oscillating unit amplitude.
17 3. Ultrasound engineering DUMO Ultralyzer parts: OSCILLATING UNITReceives electrical signal, transforms into acoustic for transfering to the medium. It has three parts:Converter: receives electrical signal and transforms into acoustic.Booster: Amplifies the signal.Sonotrode: Transfers the acoustic energy to the medium (sludge).ConverterBoosterSonotrode
18 3. Ultrasound engineering DUMO Ultralyzer parts: REACTOR BODYInside reactor body acoustic waves impact on the sludge.Each standard unit is split into 5 zones corresponding to 5 oscillating units.
19 3. Ultrasound engineering Taking advantage of each cavitation zoneEach split zone is calculated to receive maximum cavitation dosage.The effect is optimized through flow movement inside the reactor body.
20 3. Ultrasound engineering Most effective cavitation: horn type sonotrode
21 3. Ultrasound engineering Cavitation effect over sonotrodeSonotrode after 1.5 to 2 yearsNew sonotrode
22 3. Ultrasound engineering Cavitation effect over biomassCavitation causes from deagglomeration up to cell lysis.This effect is the basis of the DUMO Ultralyzer technology.
23 3. Ultrasound engineering DUMO Ultralyzer sizingFlow rate to treat is about 30 to 50% of the total TWAS.Each 5 kW unit can treat up to 30 m3/d (= 1.25 m3/h) of TWAS → 4 kWh/m3.Reactor body volume is only 29 litres, which means a real advantage in term of space.
24 3. Ultrasound engineering An example of common sizingConsider a typical WwTW with the following parameters:Qraw = 1,000 m3/h (Qmax = 1,500 m3/h) → 105 population.Primary sludge: 6, g/l.Secondary sludge: 4,250 6,7 g/l (sludge to sonicate).Thickener mixed sludge: 10, g/l → 195 m3/d.Anaerobic digester: V = 4,500 m3, HRT = 25 d, VSdeg = 45%.It is only necessary 5 kW unit for each 200 m3/d of mixed sludge…!!!
25 3. Ultrasound engineering ApplicationsBIOLOGICAL REACTOR2º CLARIFIERRASDUMO Ultralyzer works on sludge and water lines.Sludge line is for anaerobic digestion(1) and denitrification(2).Water line is for bulking & foaming.(2)WAS THICKENERTWASDIGESTER(1)THICKENED PRIMARY SLUDGEBLENDED SLUDGE
26 4. Ultrasonic disintegration of biosolids Hydrolysis: the limited step in anaerobic digestionUltrasonic disintegration is the solution to solve conventional hydrolysis step (8 to 10 days) which takes place in 90 seconds when sonicated.
27 4. Ultrasonic disintegration of biosolids Effect of sonication on sludge water phase
28 4. Ultrasonic disintegration of biosolids Degree of Disintegration: DDCODCentrifugation of the sonicated and non sonicated sludge between 10 and 30 min at 40,000 g.Filtration through a 0.45 μm membrane (soluble).COD measurement.Reference disintegration is 22 hours at 20 °C with 0.5 molar NaOH (alkaline disintegration).DDCOD= [ΔCODUS / ΔCODNaOH] * [%].
29 4. Ultrasonic disintegration of biosolids Increase in anaerobic VS degradation
30 4. Ultrasonic disintegration of biosolids How much energy is required for an adequate DDCOD?
31 4. Ultrasonic disintegration of biosolids Increasing the anaerobic digestion performance
32 4. Ultrasonic disintegration of biosolids Optimum conditions in the anaerobic digesterWAS thickened between 3 and 6%. (Although it is possible to work from 1% to 9%).HRT (Hydraulic Retention Time) ≤ 35 days.VS degradation (digestion performance) ≤ 50%.Biogas production ≤ 0,45 Nm3/Kg MVfed.Standard costs in biosolids for disposal, energy and polymer purchase.The others parameters (pH, Tª, etc…) remain as in the conventional operation.
33 4. Ultrasonic disintegration of biosolids Typical example for a HRT days digestionIncrease in VS degradation: %.Increase in biogas production: %.Reduction in sludge production: %.Increase in sludge dewatering: %.Reduction in sludge viscosity: %.Complete elimination of the problems associated with the filamentous micro organisms inside the anaerobic digester.
34 4. Ultrasonic disintegration of biosolids Cost - benefit analysis in Shanganagh WWTP (Ireland)ParameterUnitConventionalUltrasoundDifferenceVS - degradation%46.2954.968.67Biogas productionNm3/d4,2545,076823TS digested loadton/d12.0610.931.13Polymer cost€/kg2.990.00Disposal cost€/ton75.00Energy purchase€/kWh0.11Saving in polymer€/year92,15883,5018,656Saving in disposal1,501,0671,246,731254,336Saving in energy341,596407,66566,069TOTAL ULTRASONIC SAVING PER YEAR (€)329,062
35 4. Ultrasonic disintegration of biosolids The engineered solutionDeveloped know-how allows a highly detailed engineering.Predictive analysis.Mass Balance calculation.Engineering design.Start up and commissioning.Training.Service & support.
37 5. References Tablada WWTP TWAS flow of 100 m3/d. 2 anaerobic digesters of 3,300 m3 each one.HRT of 60 days.Thickened WAS through DAF.Installation of one 5 kW ultrasound reactor since 2006 equiped with all necessary peripherals.
38 5. References Tablada WWTP DAF air inside TWAS had to be removed for an effective cavitation.A de-aeration tank was designed and installed.
60 5. References Tomelloso WWTP RESULTS Start up and commissioning in November 2011.Results forecasted in project (19% of improvement in VS degradation).
61 5. References Terrassa WWTP First pilot plant has been installed in Spain for improving denitrification process.IFAS (Integrated Fixed Film of Activated sludge) reactor with 4 m3 of capacity was installed.SRT between 7 and 10 days.Flow rate of 16 m3/d.NO3 to remove about 5 mg/l.
62 5. References Terrassa WWTP Denitrification transforms NO3 in N2. It is a reduction process in which facultative bacteria, in anoxic regime, use NO3 as acceptor rather than dissolved Oxigen.It is necessary a carbon source readily biodegradable.
63 5. References Terrassa WWTP Disintegrated sludge is fantastic carbon source readily biodegradable.It is necessary to measure COD/TN releasing after sonication.
64 5. References Terrassa WWTP Enzimatic activity is highly increased after sonication, which means better biodegradability.Acceleration in TN and WAS production degradation takes place.
65 5. References Terrassa WWTP RESULTS 5 mg/l of NO3 (all required) removed with one ultrasound system equiped with 1 kW.No external carbon source.Specific WAS reduction of 25 to 30% (Lysis and Cryptic Growth process induced).
72 Activities carried out and coming soon… 5. ReferencesActivities carried out and coming soon…SPAINIRELANDPORTUGALBRASILISRAELEstivielSwords*LamegoArrudas**JerusalemNorth of SevilleGreystonesADPOnçaHaifaVillapérezWyGCarbono EficienteSabespBe’er ShevaBéteraVeolia IrelandSIMARSULCentroprojekt-PalomaresAECOMÁguas do AlgarveSanepar(*) Just awarded. (**) Expansion works of the plant.WWTP tendered, Company contacted or project studing.
73 R&D today is engineering for tomorrow… Special DUMO Ultralyzer unit has been designed for this purpose.One mobile unit with 2 kW of ultrasound power fully equiped is used for different test and proofs.
74 R&D today is engineering for tomorrow… Different DUMO Ultralyzer applications have been studied.Scientific publications about Dewatering and Disinfection have been carried out.Promising results were obtained.
75 6. R&DDewateringIt is necessary a wide range of particle size to optimize solid - liquid separation.Sonication is a good way to change particle size.After sonication water inside flocs and cells is easily delibered.
76 IMPORTANT: do not treat 100% of TWAS 6. R&DDewateringMixture of untreated TWAS and PS*Mixture of sonicated TWAS and PS.Mixture of sonicated and untreated TWAS and PS.(*) Primary Sludge.Dried matter test after dewatering (%)IMPORTANT: do not treat 100% of TWAS
77 6. R&D Dewatering Stereo-microscopic image Digested sludge after floculationDigested sludge after disintegration and floculation
78 6. R&DDisinfectionDisintection depends highly on the suspended solids contain (TSS).SS can protect bacteria and virus from the UV irradiation (Scattering).That leads to a tremendous increase in UV irradiation.
79 UV disinfection channel 6. R&DDisinfectionInstallation was designed to treat water (not sluge) before disinfection process.Only 0.11 kWh/m3 of ultrasound dosage it is necessary to avoid scattering.Sand filterUV disinfection channel
80 Evolution in the Total Coliforms elimination 6. R&DDisinfectionEvolution in the Total Coliforms elimination
81 7. Conclusions.To sum upDUMO Ultralyzer represents an innovative, tested, and sustainable technology for water & environment market.The available support allows to get quick advantage of the science and the engineering in a full plug & play project.State of the art technolgy, in terms of biosolids disintegration, is now accessible.