Fondamenti di Processi e Impianti Biotecnologici: Laboratorio · Obiettivo: applicare il bilancio...

Fondamenti di Processi eFondamenti di Processi eImpianti Biotecnologici:Impianti Biotecnologici:

LaboratorioLaboratorio

Ing. Francesco FatoneIng. Simos MalamisDott.ssa Letizia Zanetti

Nel laboratorio di ingegneria chimicadell’ambiente e dei bioprocessi:

Sistema innovativo per la rimozione dell’azoto edel fosforo: processo SCENA (Short-Cut EnhancedNutrients Abatement)

Sistema innovativo per la rimozione dell’azoto edel fosforo: processo SCENA (Short-Cut EnhancedNutrients Abatement)


Digestori anaerobici inscala da laboratorio

Si studia l’effettodell’aggiunta di acidonitroso per migliorarela produzione di biogasda fanghi didepurazione

Digestori anaerobici inscala da laboratorio

Si studia l’effettodell’aggiunta di acidonitroso per migliorarela produzione di biogasda fanghi didepurazione


UASB (Upflow Anaerobic Sludge Blanket) +POST TRATTAMENTO


1.Testa ad innesto2. O-ring Viton con collare di spinta3. Elemento metallico interno4. Elemento Ag/AgCl per il riferimento5. Gel elettrolita6. Sensore di temperatura NTC 30K7. Diaframma in PTFE8. Elettrodo in platino o in oro

IN LABORATORIOIN LABORATORIO

Prima di andare in lab....

Attenzione!!!! (acid-basi forti)

Camice e quaderno

Chiedete se vedete qualcosa che vi interessa...

Non fate troppo caso agli odori

Fate attenzione a ciò che toccate e rispettate chi lavora per voi....

Prima di andare in lab....

Attenzione!!!! (acid-basi forti)

Camice e quaderno

Chiedete se vedete qualcosa che vi interessa...

Non fate troppo caso agli odori

Fate attenzione a ciò che toccate e rispettate chi lavora per voi....

Gruppi di Laboratorio:Gruppi di Laboratorio:Gruppo AAMBROSINI GIULIABERTONCELLO LUCABISCARO ANDREABOTTURI ALICEBRENTEGANI STEFANO

CHERUBIN ARIANNA

Gruppo BFASOLO GIANLUCACRISTOVAO BORGES LORENAFERRETTO MANUELFERRON ENRICOFRASSANITO CHIARAGAIANIGO NICOLAGHOLAMI SHABNAMCHERUBIN ARIANNA

COLUSSO VALENTINACONTRINI MARIACUCCURULLO ANNADAL COLLO GIADADELAITI BEATRICEDELLI CARRI SAMANTHA

GHOLAMI SHABNAMGROAZ ILARIAJAUPAJ LEJDIMAGNAGUAGNO ENRICO

MARCHINI *** scorso anno CARIOTAZARANTONELLO FABIOMARTINATO JESSICAMASCIA FRANCESCO

Gruppi di Laboratorio:Gruppi di Laboratorio:Gruppo C

MELIS FRANCESCA

MENINI MARTA

MICHELATTI DANIELA

MODENESE SERENA

NORTILLI SIMONE

Gruppo D

RIGON MANUEL

ROSSIGNOLI ILARIA

SANTI SOFIA

SCARTEZZINI VALERIA

STANILA LIVIU

TEDESCO STEFANONORTILLI SIMONE

PALTRINIERI STEFANIA

PELLEGRINI DANIELE

PISANI ARIANNA

PITUELLO SILVIA

POLETTI STEFANIA

QUARTUCCIA MARIO

RAMOS VALENCIA NEIL EDER

RIGHETTI EDOARDO

TEDESCO STEFANO

TIHON IGOR

VEGHINI LISA

ZAGORODNYUK MARGARYTA

ZORZI GIANLUCA

ZORZIN STEFANIA

ZULIANI LUCA

DALLA VECCHIA CLAUDIA

Calendario:Calendario:day hours groups

19/11/201313:30 - 18:30 all theory Tutor

26/11/201313:30 - 18:30 group A Yh (simos)

26/11/201313:30 - 16:00 group B mass balance (letizia)

26/11/201316:00 - 18:30 group C mass balance (letizia)

03/12/201313:30 - 18:30 group C Yh (simos)03/12/201313:30 - 18:30 group C Yh (simos)

03/12/201313:30 - 16:00 group A mass balance (letizia)

03/12/201316:00 - 18:30 group D mass balance (letizia)

10/12/201313:30 - 18:30 group B Yh (simos)

10/12/201313:30 - 16:00 group C Kla (letizia)

10/12/201316:00 - 18:30 group D Kla (letizia)

17/12/201313:30 - 18:30 group D Yh (simos)

17/12/201313:30 - 16:00 group A Kla (letizia)

17/12/201316:00 - 18:30 group B Kla (letizia)

La digestione anaerobicaLa digestione anaerobica

Descrizione del processo eBilancio di massaDescrizione del processo eBilancio di massa

La riforma della politica energetica dell’Unione Europea e le conseguenti legislazionie regolamentazioni a livello nazionale, hanno dato un forte incentivo allo sviluppo ditecnologie di produzione di energia da fonti rinnovabili sempre più competitive.

con produzione dienergia: biogas

BiogasPotere calorifico:

4500 kcal/m3

BiogasPotere calorifico:

4500 kcal/m3

Matrici utilizzabili nella digestioneMatrici utilizzabili nella digestioneanaerobicaanaerobica

- biomasse agro-industriali- reflui zootecnici- fanghi di depurazione- frazione organica dei rifiuti urbani da raccolta differenziata

La scelta di una matrice rispetto ad un’altra dipende da differenti fattori. Iprincipali:- Resa potenziale di produzione di biogas- Reperibilità della matrice rispetto alla localizzazione geografica dell’impianto-Valore economico della matrice (concorrenza con altri mercati di collocazione)- Lavorabilità e facilità di gestione della matrice (necessità di pretrattamenti, potenzialiproduzioni di composti tossici o schiume in fase di digestione, …) Segue un’analisi dellecaratteristiche generali delle matrici finalizzata ad una più consapevole analisi dei delleopportunità e problematiche relative all’uso di questebiomasse.

La scelta di una matrice rispetto ad un’altra dipende da differenti fattori. Iprincipali:- Resa potenziale di produzione di biogas- Reperibilità della matrice rispetto alla localizzazione geografica dell’impianto-Valore economico della matrice (concorrenza con altri mercati di collocazione)- Lavorabilità e facilità di gestione della matrice (necessità di pretrattamenti, potenzialiproduzioni di composti tossici o schiume in fase di digestione, …) Segue un’analisi dellecaratteristiche generali delle matrici finalizzata ad una più consapevole analisi dei delleopportunità e problematiche relative all’uso di questebiomasse.

Digestore Anaerobico

Le fasi della digestione anaerobicaLe fasi della digestione anaerobica

SintrofiaSintrofia

Tutti i microrganismi coinvolti delladigestione anaerobica cooperano tra diloro. SINTROFIA: cooperazione di

microrganismi che dipendono l’un conl’altro

Tutti i microrganismi coinvolti delladigestione anaerobica cooperano tra diloro. SINTROFIA: cooperazione di

microrganismi che dipendono l’un conl’altro

Composizione del biogasComposizione del biogas

Efficienza di rimozione del substratoEfficienza di rimozione del substrato

Esistono diversi modi di esprimere l’efficienza di rimozione del substrato nel corsodel processo di digestione anaerobica non solo legati ai diversi parametri utilizzati peresprimere la sua concentrazione (sostanza solida totale, sostanza solida volatile, CODo BOD).In generale, la più semplice relazione per la conversione del substrato in biogas, vieneespressa in termini percentuali tramite la:

dove:η, percentuale di TVS rimossi, [%];Q, portata influente ed effluente, [m3/giorno];S, concentrazione di TVS nella portata influente, [kg/m3];Se, concentrazione di TVS nella portata effluente [kg/m3]

η = (Q•S - Q•Se) / (Q•S)

Digestoreanaerobico

Qin = 145 m3/day

TVS = 5 g/lQout = 145 m3/day

TVS = 3 g/l

Biogas

Digestoreanaerobico

Qin = 145 m3/day

TVS = 5 g/lQout = 145 m3/day

TVS = 3 g/l

Calcola l’efficienza di rimozione del substrato (in questo caso TVS)

Bilancio di massa digestore anaerobicoBilancio di massa digestore anaerobicoATTENZIONE, I BILANCI DI MASSA SI FANNO SULLA MASSA [Kg/day] E NONSULLE CONCENTRAZIONI!!!

Biogas

δBIOGAS = 1,2 Kg/m3KgTS/day ?

Digestoreanaerobico

Qin =…. m3/day

δFANGO ~ 1000 Kg/m3Qout = …..m3/day

δDIGESTATO = 1000 Kg/m3

m3/day • Kg/m3 =KgIN/day

m3/day • Kg/m3 =KgOUT/day

In laboratorio misurerete il contenuto diTS e TVS


KgIN/day • KgTS/Kgcampione =KgTS/day

KgOUT/day • KgTS/Kgcampione =KgTS/day

Composizione biogas: 60% CH4 e 40% CO2

PM metano =16,04 uma

PM anidride carbonica = 44,01 uma

Trova il peso molecolare medio del biogas

Bilancio di massa digestore anaerobico

Bilancio di massa digestore anaerobicoComposizione biogas: 60% CH4 e 40% CO2




PM medio biogas = (16,01*0,6)+(44,01*0,4) = 9,6 + 17,6 = 27,2 uma

Massa Molare media biogas = 27,2 g/mol

Composizione biogas: 60% CH4 e 40% CO2




PM medio biogas = (16,01*0,6)+(44,01*0,4) = 9,6 + 17,6 = 27,2 uma

Massa Molare media biogas = 27,2 g/mol

Bilancio sui TS e TVS – BIOGAS-Per quanto riguarda il biogas, i TS e i TVS sono calcolati secondo la relazione:

g TS Biogas /d = litri •[( PMmetano • %metano)+(PMCO2 • %CO2)]

litri occupati da 1mol gas a 25°C1 litro = 1 dm3

litri occupati da 1mol gas a 25°C:PV=nRTV = (1mol •0,082 [atm l mol-1 K-1] • 298,15 [K]) / 1 [atm]V = 24,4483 [l]

g TS Biogas/d = [l] • [(16,04 [g/mol] • 0,6)+ (44,01 [g/mol] • 0,4)]

24,45 [l]

g TS Biogas /day = g TVS Biogas /day = …….

Bilancio di massa digestore anaerobicoBilancio sui TS e TVS – BIOGAS-Per quanto riguarda il biogas, i TS e i TVS sono calcolati secondo la relazione:

g TS Biogas /d = litri •[( PMmetano • %metano)+(PMCO2 • %CO2)]

litri occupati da 1mol gas a 25°C1 litro = 1 dm3

litri occupati da 1mol gas a 25°C:PV=nRTV = (1mol •0,082 [atm l mol-1 K-1] • 298,15 [K]) / 1 [atm]V = 24,4483 [l]

g TS Biogas/d = [l] • [(16,04 [g/mol] • 0,6)+ (44,01 [g/mol] • 0,4)]

24,45 [l]

g TS Biogas /day = g TVS Biogas /day = …….

11--Bilancio di massa digestore anaerobicoBilancio di massa digestore anaerobico

Biogas

δBIOGAS = 1,2 Kg/m3KgTS/day ?

Obiettivo: applicare il bilancio di materia al processo di digestione anaerobica everificare se il bilancio dei TS e TVS si chiude

Dovete verificare se inbilancio si chiude, quindicalcolare l’errore% traIN e OUT

Digestoreanaerobico

Qin =…. m3/day

δFORSU ~ 1000 Kg/m3Qout = …..m3/day

δDIGESTATO = 1000 Kg/m3

m3/day • Kg/m3 =KgCAMPIONE/day

m3/day • Kg/m3 =KgCAMPIONE/day



KgCAMPIONE/day • KgTS/Kgcampione =KgTS/day

KgCAMPIONE/day • KgTS/Kgcampione =KgTS/day

SOLIDI TOTALI (TS): rappresentano la misura complessiva dei solidi presentiin un refluo; Tale misura è data dal residuo totale che si ottiene perevaporazione dalla fase liquida a 105°C.T= 105°C per 48 ore

TS = TVS + RESIDUO FISSO (Solidi inerti)

SOLIDI VOLATILI TOTALI (TVS): la misura dei TVS è data dalla differenza trail residuo totale (quello che si ottiene per evaporazione della fase liquida a T=105°C) e residuo fisso (quello che si ottiene per incenerimento a T=600°C).A 600°C la componente organica viene completamenteossidata, mentre la componente inorganica rimane sottoforma di ceneri.

http://www.isprambiente.gov.it/it/pubblicazioni/manuali-e-linee-guida/metodi-analitici-per-le-acque

TS e TVS

SOLIDI TOTALI (TS): rappresentano la misura complessiva dei solidi presentiin un refluo; Tale misura è data dal residuo totale che si ottiene perevaporazione dalla fase liquida a 105°C.T= 105°C per 48 ore

TS = TVS + RESIDUO FISSO (Solidi inerti)

SOLIDI VOLATILI TOTALI (TVS): la misura dei TVS è data dalla differenza trail residuo totale (quello che si ottiene per evaporazione della fase liquida a T=105°C) e residuo fisso (quello che si ottiene per incenerimento a T=600°C).A 600°C la componente organica viene completamenteossidata, mentre la componente inorganica rimane sottoforma di ceneri.

http://www.isprambiente.gov.it/it/pubblicazioni/manuali-e-linee-guida/metodi-analitici-per-le-acque

Mettere il crogiolo vuoto per almeno 20 minuti in stufa dopo aver scritto una sigla diriconoscimento del campione sia sul lato sia sul fondo del crogiolo;lasciar raffreddarenell’essiccatore e pesare la tara (P1)Inserire il campione nel crogiolo e pesare il lordo (P2)Il campione nel crogiolo va messo in stufa a 105°C per 48 ore; lasciar raffreddarenell’essiccatore per cerca 10 minuti e pesare (P3)Lasciare in muffola a 550-600°C per altre 24 ore; lasciar raffreddare nell’essiccatore e pesare(P4).

ACCORGIMENTO: per evitare la rottura del crogiolo eseguire, prima del raffreddamento, unpassaggio in stufa a 105°C per 30 minuti.

FORMULE:TS [g/Kg] = {(P3 - P1) / (P2 - P1)} •1000

TVS [g/Kg] = { {(P3 - P1) – (P4 - P1)} / (P2 - P1) } •1000TVS %TS = (g TVS / g TS) •100

Materiali e metodi, TS e TVS(Bilancio di materia digestore anaerobico)

Mettere il crogiolo vuoto per almeno 20 minuti in stufa dopo aver scritto una sigla diriconoscimento del campione sia sul lato sia sul fondo del crogiolo;lasciar raffreddarenell’essiccatore e pesare la tara (P1)Inserire il campione nel crogiolo e pesare il lordo (P2)Il campione nel crogiolo va messo in stufa a 105°C per 48 ore; lasciar raffreddarenell’essiccatore per cerca 10 minuti e pesare (P3)Lasciare in muffola a 550-600°C per altre 24 ore; lasciar raffreddare nell’essiccatore e pesare(P4).

ACCORGIMENTO: per evitare la rottura del crogiolo eseguire, prima del raffreddamento, unpassaggio in stufa a 105°C per 30 minuti.

FORMULE:TS [g/Kg] = {(P3 - P1) / (P2 - P1)} •1000

TVS [g/Kg] = { {(P3 - P1) – (P4 - P1)} / (P2 - P1) } •1000TVS %TS = (g TVS / g TS) •100

IN = OUT

Kg TS Fanghi/day = Kg TS biogas/day + Kg TS digestato/day

IN = OUTKg TVS Fanghi/day = Kg TVS biogas/day + Kg TVS digestato/day

IL BILANCIO SI CHIUDE? (esempio con i TVS)

SI CALCOLA LA % DI ERRORE TRA I Kg TVS/day IN INGRESSO E IN USCITA

Errore % = (Kg TVS/day INGRESSO - Kg TVS/day USCITA) * 100

Kg TVS/day INGRESSO

Bilancio di massa digestore anaerobicoTS E TVS

IN = OUT

Kg TS Fanghi/day = Kg TS biogas/day + Kg TS digestato/day

IN = OUTKg TVS Fanghi/day = Kg TVS biogas/day + Kg TVS digestato/day

IL BILANCIO SI CHIUDE? (esempio con i TVS)

SI CALCOLA LA % DI ERRORE TRA I Kg TVS/day IN INGRESSO E IN USCITA

Errore % = (Kg TVS/day INGRESSO - Kg TVS/day USCITA) * 100

Kg TVS/day INGRESSO

Se l’errore % non supera il 10%, il bilancio si chiude

La produzione specifica di biogas (SGP) del rifiuto solido urbano è 0,8 m3 biogas/Kg TVSalimentati.

All’interno di un digestore anaerobico inserisco 100 Kg di questo substrato avente 80%TS e il rapporto TVS/TS è 0,9.

Calcola i m3 di biogas derivanti da questo substrato.

Esercizio

La produzione specifica di biogas (SGP) del rifiuto solido urbano è 0,8 m3 biogas/Kg TVSalimentati.



100 kg substrato * 0,8 = 80 Kg TS

80 Kg TS * 0,9 = 72 Kg TVS

m3 biogas =72 Kg TVS *0,8 m3 biogas/Kg TVS alimentati = 57,6 m3

EsercizioLa produzione specifica di biogas (SGP) del rifiuto solido urbano è 0,8 m3 biogas/Kg TVSalimentati.



100 kg substrato * 0,8 = 80 Kg TS

80 Kg TS * 0,9 = 72 Kg TVS

m3 biogas =72 Kg TVS *0,8 m3 biogas/Kg TVS alimentati = 57,6 m3

Esperienze di laboratorio

-Bilancio di materia sul digestore anaerobico (sia TS cheTVS)

-Calcolo del coefficiente di resa cellulare eterotrofa (YH)

- Calcolo Kla

-Bilancio di materia sul digestore anaerobico (sia TS cheTVS)

-Calcolo del coefficiente di resa cellulare eterotrofa (YH)

- Calcolo Kla

Experimental exerciseDetermination of biomass yield (YΗ)

University of Verona19/11/2013

Experimental exerciseDetermination of biomass yield (YΗ)

Why do we need to treat wastewater?Why do we need to treat wastewater?Parameter Typical rangeTSS 70-250 mg/L

BODCOD

100- 300 mg/L250 – 800 mg/L

TKN 20-85 mg/L

PO4-P 3-10 mg/L

TP 5-12 mg/L

• Wastewater contains organic and inorganicsubstances that can harm the waterrecipients. Common environmentalproblems

• De-oxygenation of water recipients• Eutrophication due to nutrients

• Treated effluents needs to satisfy certainrequirements before they are dischargedTP 5-12 mg/L

• Wastewater contains organic and inorganicsubstances that can harm the waterrecipients. Common environmentalproblems

• De-oxygenation of water recipients• Eutrophication due to nutrients

• Treated effluents needs to satisfy certainrequirements before they are discharged

Parameter Concentration (mg/l)Normal recipient

Concentration (mg/l)Sensitive recipient

COD (mg/l) 125 125

BOD5 (mg/l) 25 25

TSS (mg/l) 35 (>10.000 p.e.)60 (2.000 – 10.000 p.e.) 35 (>10.000 p.e.)

N (mg/l) - 15(10.000 – 100.000 p.e.)10 (> 100.000 p.e.)

P (mg/l) - 2 (10.000 – 100.000 p.e.)1 (> 100.000 p.e.)

Directive91/271/EC

requirements

Purpose of Biological TreatmentPurpose of Biological Treatment

Oxidize constituents into an acceptable end product

Remove nutrients (N and P)◦ Nitrification and denitrification◦ Enhanced biological phosphorus removal (and or chemical removal)

Oxidize constituents into an acceptable end product

Remove nutrients (N and P)◦ Nitrification and denitrification◦ Enhanced biological phosphorus removal (and or chemical removal)

Purpose of Biological TreatmentPurpose of Biological Treatment

Treatment stages

Preliminary Treatment – Removal of grit and coarse material insuspension – Protection of equipment and facilities.

Primary Treatment – Removal of settleable solids and fats (oils andgreases). Generates stabilized sludge.

Secondary (biological) treatment Oxidation and removal of biodegradable organic matter. Generates

biological sludge to be stabilized and properly disposed off. Removal of nutrients (N, P)

Advanced Treatment – Polishing of effluent for reuse
















• Bacteria perform the basic functions of:• Oxidation of substrate (i.e. food) to produce energy• Growth (formation of new biomass using the generated energy)• Endogenous respiration – decay

• Organic carbon oxidation under aerobic conditions• Heterotrophic bacteria in the presence of oxygen oxidize organic matter to

produce energy• The energy is then used to produce new biomass (i.e. growth)

Bacterial growth and decay• Bacteria perform the basic functions of:

• Oxidation of substrate (i.e. food) to produce energy• Growth (formation of new biomass using the generated energy)• Endogenous respiration – decay

• Organic carbon oxidation under aerobic conditions• Heterotrophic bacteria in the presence of oxygen oxidize organic matter to

produce energy• The energy is then used to produce new biomass (i.e. growth)

Ripartizione del substrato nellaRipartizione del substrato nellabiosintesi aerobicabiosintesi aerobica

BacterialBacterial endogenousendogenous decaydecay

Biological oxygen demand (BOD), chemical oxygen demand (COD) or volatile solids(VS) are traditionally used to characterize organic matter in wastewater.These parameters determine the quantity of the organic matter present. COD and VSare measures of the total concentration of organic matter and BOD indicates the totalamount of biodegradable organic matter. However, neither method gives detailedinformation on thecomposition of the fractions of biodegradable organic matter.


• Endogenous decay of biomass is the loss in the mass of the cellsdue to the following reasons:• Death of cells• Predation by microorganisms higher in the food chain• Oxidation of internal products stored in the bacteria for cell

maintenance• Consequences of endogenous decay

• Less sludge production• Higher oxygen requirements• Increase in treated effluent COD (by products)



• Endogenous decay of biomass is the loss in the mass of the cellsdue to the following reasons:• Death of cells• Predation by microorganisms higher in the food chain• Oxidation of internal products stored in the bacteria for cell

maintenance• Consequences of endogenous decay

• Less sludge production• Higher oxygen requirements• Increase in treated effluent COD (by products)

Organic matter fractionationOrganic matter fractionation

Crude parameters like biological oxygen demand (BOD), chemical oxygendemand (COD) or volatile solids (VS) are traditionally used to characterizeorganic matter in wastewater.

These parameters determine the quantity of the organic matter present.COD and VS are measures of the total concentration of organic matter andBOD indicates the total amount of biodegradable organic matter.

Neither method gives detailed information on the composition of thefractions of biodegradable organic matter.

Crude parameters like biological oxygen demand (BOD), chemical oxygendemand (COD) or volatile solids (VS) are traditionally used to characterizeorganic matter in wastewater.

These parameters determine the quantity of the organic matter present.COD and VS are measures of the total concentration of organic matter andBOD indicates the total amount of biodegradable organic matter.

Neither method gives detailed information on the composition of thefractions of biodegradable organic matter.

A detailed characterization of the wastewater organic matter can beachieved, dividing the total COD into fractions with different microbiologicalproperties.

TOTAL COD

COD B COD NB

COD RB COD SB COD PNB COD SNB

COMPLEX VFA COLOIDAL PARTICULATE

COD: Definition and fractionation

Chemical Oxygen Demand (COD): the amount of oxygen needed to chemically oxidize theorganic constituents. The determination of COD gives the overall level of organiccontamination.

Chemical Oxygen Demand (COD): the amount of oxygen needed to chemically oxidize theorganic constituents. The determination of COD gives the overall level of organiccontamination.

TOTAL COD

COD B COD NB

COD RB COD SB COD PNB COD SNB

COMPLEX VFA COLOIDAL PARTICULATE

B – biodegradable; NB – nonbiodegradable; RB – readly biodegradable;SB – slowly biodegradable; PNB – nonbiodegradable (particulate);SNB – nonbiodegradable (soluble) VFA – Volatile Fatty Acids

The fractionation is necessary for the simulation of the operation of WWTP by usingvarious simulating models (i.e. IAWQ) and it is useful for the design of activated sludgesystems with nutrients removal.

QuantifyingQuantifying BiomassBiomass

• Bacteria Cells = Biomass– Often measured as volatile suspended solids (VSS)– Is VSS entirely biomass?– Other approaches: particulate COD, protein, DNA

• Biomass yield (YH) = g biomass produced / gsubstrate consumed– Substrate is typically the constituent in the

wastewater that is electron donor (energy source)

• Bacteria Cells = Biomass– Often measured as volatile suspended solids (VSS)– Is VSS entirely biomass?– Other approaches: particulate COD, protein, DNA

• Biomass yield (YH) = g biomass produced / gsubstrate consumed– Substrate is typically the constituent in the

wastewater that is electron donor (energy source)

In an activated sludge system oxygen consumption is mainly due to: Endogenous respiration, that gives the energy that is required for the cell

maintenance. It is measured in the absence of substrate, and it representsthe contribution of endogenous oxygen consumption;

Degradation of the substrate: the consumption of oxygen for the oxidation oforganic matter or nitrogen compounds and for the synthesis of new cells. Itrepresents the contribution of exogenous oxygen consumption.

Oxygen consumption: means the total amount of oxygen used by a biologicalsystem to perform the catabolic and anabolic processes in a certain time.

The rate of oxygen consumption represents the amount of oxygen used perunit of time from the system and is related to the speed – velocity of thebiological reaction.

Oxygen consumptionOxygen consumption

In an activated sludge system oxygen consumption is mainly due to: Endogenous respiration, that gives the energy that is required for the cell

maintenance. It is measured in the absence of substrate, and it representsthe contribution of endogenous oxygen consumption;

Degradation of the substrate: the consumption of oxygen for the oxidation oforganic matter or nitrogen compounds and for the synthesis of new cells. Itrepresents the contribution of exogenous oxygen consumption.

Oxygen consumption: means the total amount of oxygen used by a biologicalsystem to perform the catabolic and anabolic processes in a certain time.

The rate of oxygen consumption represents the amount of oxygen used perunit of time from the system and is related to the speed – velocity of thebiological reaction.

The rate of oxygen consumption for the degradation of the substrate andof cellular synthesis is much higher than that of the endogenousrespiration.

The readily biodegradable substrate in wastewater exhibits high oxygendemand in short-term; as the substrate is consumed, the rate of oxygenconsumption decreases progressively, reaching the rate of endogenousrespiration.



Rate of oxygen consumptionRate of oxygen consumption





Is a general term that encompasses a number of techniquesused for measuring the ‘rate of respiration of a living organism’by measuring its rate of change of oxygen and/or carbondioxide.

is an important index of enzymatic – metabolic activity of abiological system

Respirometric tests are used to obtain information onmetabolic activity and on the utilization rate of substrates

We obtain information for the:Biomass yield coefficient: YΗ

Rate of nitrification, denitrification, oxidation of carbonCOD fractionation






Respirometry











RespirometricRespirometric test : Whichtest : Whichfractions we can estimate?fractions we can estimate?

rbCOD

+

sbCOD

CODbiodegradable

rbCOD

+

sbCOD

CODbiodegradable

The parameter YThe parameter YHH

YH is the heterotrophic yield (gCODbiomass/gCODsubstrate)

YH = CODproduced biomass / CODconsumedYH = (CODconsumed – COD oxidized) / CODconsumed

YH = 1 – ΔDOconsumed / CODadded

Nel caso di composti puri il valore di COD aggiunto può essere posto al valoreteorico di COD relativo alla massa di composto dosata nel respirometro.

YH = CODproduced biomass / CODconsumedYH = (CODconsumed – COD oxidized) / CODconsumed

YH = 1 – ΔDOconsumed / CODadded

Nel caso di composti puri il valore di COD aggiunto può essere posto al valoreteorico di COD relativo alla massa di composto dosata nel respirometro.

Value of YH in literature 0.67

TheThe experimentexperiment

Respirometer Martina

Oxygen control throughautomatic respirometerOxygen control throughautomatic respirometer

Batch reactor with: pre-aerated activated sludge probe for recording the ‘dissolved

oxygen’ (DO) temperature probe air diffusers system for data acquisition

RespirometerRespirometer

Batch reactor with: pre-aerated activated sludge probe for recording the ‘dissolved

oxygen’ (DO) temperature probe air diffusers system for data acquisition

Put in a batch reactor 0.5 L of pre-aerated activated sludge Introduce a magnetic stirrer in the reactor and the

oxygonometer (DO: ~ 7-8 mg/L); Add ~ 10 mg/L of allylthiourea (ATU) in order to inhibit

nitrification Stop aeration and start measuring the concentration of DO Stop the measurement when the DO concentration is below

1 mg/L Add different concentrations of sodium acetate substrate

◦ 2 mg/L◦ 4 mg/L◦ 6 mg/L◦ 8 mg/L

Take a sample of activated sludge from the reactor anddetermine MLSS and MLVSS

Procedure for the determination of YH

Put in a batch reactor 0.5 L of pre-aerated activated sludge Introduce a magnetic stirrer in the reactor and the

oxygonometer (DO: ~ 7-8 mg/L); Add ~ 10 mg/L of allylthiourea (ATU) in order to inhibit

nitrification Stop aeration and start measuring the concentration of DO Stop the measurement when the DO concentration is below

1 mg/L Add different concentrations of sodium acetate substrate

◦ 2 mg/L◦ 4 mg/L◦ 6 mg/L◦ 8 mg/L

Take a sample of activated sludge from the reactor anddetermine MLSS and MLVSS

8

DO

(m

g/L)

DeterminationDetermination ofofYYHH (1/2)(1/2)

Addition of substrate (S) at different concentrationsThe drop ΔDO represents the consumption of oxygen due to oxidation and

endogenous respiration for COD added = 8 mg/L

0

2

4

6

0 5 10 15 20 25

DO

(m

g/L)

Time (min)

∆DO = ΔDOendogenous + ΔDOoxidized

Endogenous decay rate

DeterminationDetermination ofofYYHH (2/(2/22))

COD added(mg/L)

Timerequired

(min)

ΔDO consumed(mg/L)

ΔDO endogenous

(mg/L)ΔDO oxidized

(mg/L)

2 1.63 0.57 0.26 0.31

4 2.73 0.99 0.44 0.55

6 4.83 1.78 0.78 1.00

8 5.43 2.08 0.88 1.218 5.43 2.08 0.88 1.21

y = 0.16xR² = 0.9796

0

0,4

0,8

1,2

1,6

0 2 4 6 8 10

ΔD

Oox

idiz

ed(m

g/L)

COD consumed (mg/L)

= 1 – slope = 0.84

Determination of COD fractions with the measurement of OxygenDetermination of COD fractions with the measurement of OxygenUptake Rate (OUR)Uptake Rate (OUR)

The method aims at the determination of the various COD fractionsthrough their correlation with the oxygen consumption rates that aremeasured in batch experiments where the wastewater is mixed with thebiomass.The fractionation is based on the correlation of the concentration ofoxygen that is consumed for each COD fraction with the concentration ofeach fraction that exists in wastewater.




Organic matter fractionationOrganic matter fractionation

- By calculating the area below thecurve of the oxygen uptake rate wedetermine the oxygen that isconsumed for the metabolism of easilybiodegradable, easily hydrolysable andslowly hydrolysable COD.- By using the yield coefficient YH(coefficient for the conversion ofdissolved oxygen in COD) we candetermine the COD that correspondsin each group of organic matter. Forthe determination of YH we areperforming oxygen uptake experimentsby adding known amount of sodiumacetate.

- By calculating the area below thecurve of the oxygen uptake rate wedetermine the oxygen that isconsumed for the metabolism of easilybiodegradable, easily hydrolysable andslowly hydrolysable COD.- By using the yield coefficient YH(coefficient for the conversion ofdissolved oxygen in COD) we candetermine the COD that correspondsin each group of organic matter. Forthe determination of YH we areperforming oxygen uptake experimentsby adding known amount of sodiumacetate.

Respirometric test (OUR)Respirometric test (OUR)

The coupling between oxygen and substrate consumption canbe used to calculate the amount of substrate consumed.

When interpreting the OUR curve it is essential to know themrespiration due to the biomass itself, called the endogenousrespiration. This respiration is assumed to be caused bymaintenance of the biomass. The concept is to subtract therespiration from the measured respiration in order todetermine the true yield coefficient.

The direct registration of the oxygen consumption rate ina biological process allows us to get a first insight intothe metabolism of the micro-organisms.

When interpreting the OUR curve it is essential to know themrespiration due to the biomass itself, called the endogenousrespiration. This respiration is assumed to be caused bymaintenance of the biomass. The concept is to subtract therespiration from the measured respiration in order todetermine the true yield coefficient.

Phase I: The amount of added substrate expressed as COD, which has been oxidised, isthen equal to the white area in Fig. 1. Phase II: “slowly” readily biodegradable COD(RBCOD)

The area between the complete respirogram and theendogenous respiration identifies the total oxygen (DO) usedfor oxidation of all the biodegradable COD in the wastewater(bCOD).

The two areas can be calculated using the integral of thecurves or by the method of trapezoids. Based on this methodthe area under the curve is divided in finite elements oftrapezoidal shape delimited vertically by two consecutivevalues of OUR mutually spaced by a time interval Δt.

OUR determinationOUR determination

The area between the complete respirogram and theendogenous respiration identifies the total oxygen (DO) usedfor oxidation of all the biodegradable COD in the wastewater(bCOD).

The two areas can be calculated using the integral of thecurves or by the method of trapezoids. Based on this methodthe area under the curve is divided in finite elements oftrapezoidal shape delimited vertically by two consecutivevalues of OUR mutually spaced by a time interval Δt.

OUR graphOUR graph

Substrateaddition

Substrateaddition

Total DO consumed: calcolo dell’area sottesa mediante il metodo della sommadell’area dei trapezi

OUR acetateOUR acetate

At first the OUR measurement gives a very fast response and then after a short period, therespiration rate levels off.The first increase of the OUR curve can be explained by the adaptation of the organisms to thissudden much higher concentration of organic substrate or it could be caused by growth of thebiomass.Sudden drop: indicating that the added substrate has been removed

What data we get ?What data we get ?

01234567

0 2000 4000 6000 8000 10000 12000

mgD

O/L

Time (sec)

Endogenousconsumption

Substrate consumption

01234567

0 2000 4000 6000 8000 10000 12000

mgD

O/L

Time (sec)

normalization

sOUR= _____OURMLVSS

biomass

sOUR(20°C) = sOUR (T) /1,099^ (T-20)

temperature

Mixed liquor suspended solids (MLSS)Mixed liquor suspended solids (MLSS)

is the concentration of suspended solids, in an aeration tank during theactivated sludge process, which occurs during the treatment of waste water.consists mostly of microorganisms and non-biodegradable suspended matter.is an important part of the activated sludge process to ensure that there is asufficient quantity of active biomass available to consume the applied quantityof organic pollutant at any time.

is the concentration of suspended solids, in an aeration tank during theactivated sludge process, which occurs during the treatment of waste water.consists mostly of microorganisms and non-biodegradable suspended matter.is an important part of the activated sludge process to ensure that there is asufficient quantity of active biomass available to consume the applied quantityof organic pollutant at any time.

MLVSS is the portion of the MLSS that is actually eating the incoming food .

The volatile solids concentration in a sample of mixed liquor will consistmostly of microorganisms and organic matter.

MLVSS is the portion of the MLSS that is actually eating the incoming food .

The volatile solids concentration in a sample of mixed liquor will consistmostly of microorganisms and organic matter.

Mixed liquor volatile suspended solids (MLVSS)

MLSS and MLVSS are indicative of biomass....but MLVSS is more indicative of true biomass than MLSS since MLSS includesinorganic constituents.

MLSS and MLVSS are indicative of biomass....but MLVSS is more indicative of true biomass than MLSS since MLSS includesinorganic constituents.

SolidsSolids

Total Solids(TS)

Total suspendedsolids (TSS)

Totaldissolved

solids (TDS)Total suspended

solids (TSS)

Volatilesuspendedsolids (VSS)

Fixed (inert)suspended

solids

Totaldissolved

solids (TDS)

Volatiledissolved

solids

Fixed (inert)dissolved

solids

Distinction between suspended and solubleDistinction between suspended and soluble

Suspended solids have asize > 1 μm (10-6 m)

Dissolved solids < 1 μm We may also distinguish

a third category that liesbetween suspendedsolids and dissolvedsolids that is colloidalsolids for solids having asize of the order of 0.1-1μm

Suspended solids have asize > 1 μm (10-6 m)

Dissolved solids < 1 μm We may also distinguish

a third category that liesbetween suspendedsolids and dissolvedsolids that is colloidalsolids for solids having asize of the order of 0.1-1μm

To determine the total solids in a water/wastewater sample we needto remove all the water and then measure solids

How do we remove water? Simple by evaporation

Procedure Take a clean crucible (crogiolo) and weight it (m1= mass of clean crucible -

g)Add specific volume of water/wastewater sample to the crucible (V - mL)Put in the oven at 105oC (stufa) until all water evaporates (how do we now

that?)Remove the crucible from oven and let it reach room temperature. Then

weight it (m2 = mass of crucible and total solids - g) Total solids (mg/L) = (m2 – m1)/V * 106







But how do we measure total solids?













To determine the volatile solids we need to place the dried sample atvery high temperature (550oC) to volatilize the solids

ProcedurePlace the previously dried crucible that contain s the dried solids at

550oC (muffola) and maintain for at least 20 min

Remove crucible, allow to reach room temperature and weight (m3 =mass of crucible and fixed-inert (non volatile) solids

Volatile solids VS (mg/L) = (m2-m3)/V*106






But how do we measure volatile solids?











Biomass Yield (Y = g cell/g substrate)Biomass Yield (Y = g cell/g substrate)

COD Mass Balance (Stoichiometry)◦ Assume substrate as glucose◦ Neglect nutrient other than N

What is the yield (Y) based on thisstoichiometry?

COD Mass Balance (Stoichiometry)◦ Assume substrate as glucose◦ Neglect nutrient other than N

What is the yield (Y) based on thisstoichiometry?

COD of Glucose (g O2 / g glucose)COD of Glucose (g O2 / g glucose)

Cellular Mass Balance (Stoichiometry)◦ Assume substrate as glucose◦ Neglect nutrient other than N

What is the yield (Y) based on thisstoichiometry (change in O2 over change inglucose)?

Cellular Mass Balance (Stoichiometry)◦ Assume substrate as glucose◦ Neglect nutrient other than N

What is the yield (Y) based on thisstoichiometry (change in O2 over change inglucose)?

Theoretical Yield[(g cell / g glucose) / (g COD O2 / g glucose)]

Maximum yield… actual yield will be morebecause not all substrate is converted to cellmass (synthesis) since some is needed for cellmaintenance Solve for the theoretical yield given the

following

Maximum yield… actual yield will be morebecause not all substrate is converted to cellmass (synthesis) since some is needed for cellmaintenance Solve for the theoretical yield given the

following

Theoretical Yield[(g cell / g glucose) / (g COD O2 / g glucose)]

Solve for the theoretical yield

Fondamenti di Processi e Impianti Biotecnologici: Laboratorio · Obiettivo: applicare il bilancio...

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