AQUAPONIC SLUDGE DIGESTION FOR ORGANIC REDUCTION AND NUTRIENTS MINERALISATION IN UASB REACTORS

by Boris Delaide

Work in collaboration with: Simon Goddek, Karel Keesman and M. Haissam Jijakli.

Integrated and Urban Plant Pathology Laboratory

One loop aquaponics

Introduction FormulaAerobic vs Anaerobic

UASB performances

UASB effluents Perspectives

Fish tank SumpBiofilter PumpHydroponic beds

Mechanical filter

Low concentration of mineral elements in solution

- Macroelements:

N, P, K, Ca, Mg, S

- Microelements:

Fe, B, Cu, Zn, Mn, Mo

Fish tank SumpBiofilter PumpHydroponic beds

Mechanical filter

Introduction FormulaAerobic vs Anaerobic

UASB performances

UASB effluents Perspectives

Nutrients lost by sludge spillage

Sludge

Fish tank SumpBiofilter PumpHydroponic beds

Mechanical filter

Introduction FormulaAerobic vs Anaerobic

UASB performances

UASB effluents Perspectives

Sludge digestion for mineral elements recovery

Digestionin

bioreactor

Sludge

Fish tank SumpBiofilter Pump Hydroponic bedsMechanical filter

Macro and microelements

mineralised

Introduction FormulaAerobic vs Anaerobic

UASB performances

UASB effluents Perspectives

Formula used for COD – TS reduction:

Digester

𝑇𝑆 = 1 −∆𝑇𝑆 + 𝑇𝑇𝑆 𝑜𝑢𝑡

𝑇𝑇𝑆 𝑖𝑛

𝑻𝑻𝑺 𝒐𝒖𝒕𝑻𝑻𝑺 𝒊𝒏 ∆𝑻𝑺

where ∆𝑇𝑆 is the TS inside the reactor at the end of the experiment minus the TS inside the reactor at the beginning of the experiment, 𝑇𝑇𝑆 𝑜𝑢𝑡 is the total TS outflow and 𝑇𝑇𝑆 𝑖𝑛 is the total TS inflow.

Introduction Formula Aerobic vs

AnaerobicUASB

performancesUASB effluents Perspectives

Formula used for elements mineralisation:

Where 𝑁𝑅 is the nutrient recovery at the end of the experiment in percent, 𝐷𝑁𝑜𝑢𝑡is the total mass of dissolved nutrient in the outflow, 𝐷𝑁𝑖𝑛 the total mass of dissolved nutrient in the inflow , and 𝑇𝑁𝑖𝑛 the total mass of dissolved plus undissolved nutrients in the inflow.

DigesterDNout

DNin

+

TNin

UNin

𝑁𝑅 =𝐷𝑁𝑜𝑢𝑡 −𝐷𝑁𝑖𝑛𝑇𝑁𝑖𝑛 − 𝐷𝑁𝑖𝑛

Introduction Formula Aerobic vs Anaerobic

UASB performances

UASB effluents Perspectives

Aerobic vs Anaerobic sludge digestion in simple reactors

ZHAW1, ULg2 and WUR3

1 ZHAW Life Sciences und Facility Management, Grüentalstrasse 14, Postfach, 8820 Wädenswil2 Integrated and Urban Plant Pathology Laboratory, Université de Liège, Avenue Maréchal Juin 13, 5030 Gembloux, Belgium3Wageningen University, Wageningen Institute of Animal Sciences, Aquaculture and Fisheries Group, P.O. Box 338, 6700 AH Wageningen, The Netherlands

Introduction FormulaAerobic vs Anaerobic

UASB performances

UASB effluents Perspectives

Anaerobic vs Aerobic sludge digestion in simple reactors

a

a

a

a

Introduction FormulaAerobic vs Anaerobic

UASB performances

UASB effluents Perspectives

Anaerobic vs Aerobic elements mineralisation performances

a

b*

a a

aa

a a

Introduction FormulaAerobic vs Anaerobic

UASB performances

UASB effluents Perspectives

UASBEGSB

ULg: one setWUR: two sets

Introduction FormulaAerobic vs Anaerobic

UASB performances

UASB effluents

Perspectives

pH in reactors

Introduction FormulaAerobic vs Anaerobic

UASB performances

UASB effluents

Perspectives

VFA in reactors

Introduction

FormulaAerobic vs Anaerobic

UASB performances

UASB effluents

Perspectives

Sludge organic reduction performances

Introduction FormulaAerobic vs Anaerobic

UASB performances

UASB effluents

Perspectives

Sludge reduction and mineralisation performances

Introduction FormulaAerobic vs Anaerobic

UASB performances

UASB effluents

Perspectives

• N mineralisation: protein degradation

NH4+

• P, K, Ca, Mg mineralisation: solubilisation low pH of precipitated minerals

- Struvite: (NH4)Mg(PO4) 6(H2O)- Calcium phosphate, Hydroxyapatite: Ca5(PO4)3(OH)

Introduction

FormulaAerobic vs Anaerobic

UASB performances

UASB effluents

Perspectives

TS and COD in effluents comparison

Introduction

FormulaAerobic vs Anaerobic

UASB performances UASB effluents Perspectives

Macroelements in UASB effluents compared to hydroponics

Introduction FormulaAerobic vs Anaerobic

UASB performances UASB effluents Perspectives

Microelements in UASB effluents compared to hydroponics

Introduction FormulaAerobic vs Anaerobic

UASB performances UASB effluents Perspectives

Two-step digestion + post-treatment?

UASB➢ pH 6.5 – 7.5➢ Organic

reduction ➢ N mineralisation➢ Biogas

Acid reactor

➢ pH 4.5 to 5.5➢ Macro and

microelements mineralisation

Freshsludge

Post-treatment

?

Introduction FormulaAerobic vs Anaerobic

UASB performances

UASB effluents Perspectives

RAS

HydroponicsUASB +

Sludge mineralisation

Decoupled AquaPonic System: DAPS

Introduction FormulaAerobic vs Anaerobic

UASB performances

UASB effluents Perspectives

Thank you for your attention!