TRATAMIENTO DE SUERO LÁCTEO MEDIANTE UN BIORREACTOR ANAEROBIO DE MEMBRANA PARA LA RECUPERACIÓN DE AGUA Y ENERGÍA

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1 TRATAMIENTO DE SUERO LÁCTEO MEDIANTE UN BIORREACTOR ANAEROBIO DE MEMBRANA PARA LA RECUPERACIÓN DE AGUA Y ENERGÍA Judit Ribera¹, Montse Calderer¹, Martina Polášková², Jan Svoijtka³, Irene Jubany¹, Xavier Martínez-Lladó¹ ¹ Fundació CTM Centre Tecnològic, Manresa, SPAIN ² ASIO, Brno, CZECH REPUBLIC ³ FHNW, Muttenz, SWITZERLAND 1

2 RESEARCH FRAMEWORK The research presented is conducted in the framework of an European Union competitive project. Project ID: Innovation Demonstration for a Competitive and Innovative European Water Reuse Sector 2

3 INTRODUCTION Current linear model of natural consumption is not sustainable and the trend should shift to circular economy. Wastewater can be thought of as a misplaced resource well-suited for recovery of energy, valuable materials, and clean water. 3

4 INTRODUCTION Dairy industry is one of the main sources of industrial effluent generation in Europe Cheese whey BOD₅/COD ratio > 0.5 High sodium contents Acidic ph and low alkalinity organic N, VFA 93-94% water Cow manure Suspended solids and fibrous material Enough alkalinity to develop anaerobic process 4

5 INTRODUCTION Chemical characteristics of cheese whey and cow manure Cheese whey Cow manure (sieved 2 mm) ph uph 3.7 ± ± 0.7 Electrical conductivity ms/cm 9.8 ± ± 0.8 TSS g/l VSS g/l Alkalinity mg/l < ± 4610 VFA mg/l COD g/l 65.2 ± ± 7.6 TN mg/l 351 ± ± 370 TKN mg/l 793 ± ± 337 NH₄+ mg/l 35.9 ± ± 117 NO₃ mg/l 3.1 ± ± 0.6 NO₂ mg/l 88.4 ± ± 3.8 SO₄² mg/l 113 ± ± 4.2 Cl mg/l 2420 ± ± 132 TP mg/l 257 ± ± 95.2 PO₄³ mg/l 456 ± ± 59 Ca²+ mg/l 716 ± ± 96.6 Mg²+ mg/l 75.7 ± ± 30.5 Na+ mg/l ± ± 47.1 K+ mg/l 1990 ± ± 202 5

6 INTRODUCTION Anaerobic digestion of cheese whey Anaerobic digestion Energy production High OLR Low sludge production Treatment of high organic content industrial WW Long SRT No N or P removal Mesophilic conditions High operational costs Anaerobic digestion of cheese whey Alkalinity supplementation to avoid VFA accumulation Much of cheese whey treatment has been focused in anaerobic digestion as compiled in Prazeres et al. (2012) and Carvalho et al. (2013) recent reviews. 6

7 INTRODUCTION Anaerobic Membrane Bioreactor (AnMBR) Coupling anaerobic digestion to membrane filtration to form an AnMBR system. HRT High quality effluent obtained Compact technology Membrane fouling 7

8 INTRODUCTION AnMBR for cheese whey treatment Saddoud et al. (2007) Memthane technology from Veolia Scale Lab Configuration Characteristics of membrane Type of reactor External Ceramic, pore size = 0.2 µm 2 phase, anaerobic, CSTR/CSTR+M Reactor volume (m³) 0.007/0.02 Temp ( C) 37±2 HRT (d) 1/4 SRT (d) -/ OLR (kg COD/m³/day) -/ MLSS (g/l) ~8.5 Feed COD (g/l) 68.6±3.3 Feed TSS (g/l) 1.35±0.06 Effluent COD (mg/l) -/- COD removal efficiency 18%/79% Bioresource Technology 98 (2007)

9 OBJECTIVES Objectives This work aims to study a one-stage AnMBR for the treatment of cheese whey and the effect in ph control when codigesting it with cow manure with the final aim to recover energy and water, which can be reused in the farm or cheese whey manufacturing facilities. AnMBR Waste from agricultural application Nutrients recovery Water reuse Energy production 9

10 MATERIALS AND METHODS Bench scale set-up Bioreactor volume: 10L Sludge volume used: 9L HRT: 15 days Temperature: 35 C ph control (NaOH) External polymeric flat sheet membrane module (40 cm², pore size: 35 nm) Feeding Level sensor Feed inlet ph sensor Biogas outlet TO membrane module Cheese whey (day 0 to 79) Cheese whey codigestion with cow manure (day 79 to 278) Cheese whey NaOH Membrane module 10

11 Biogas production (ml biogas/h) Biogas Production (m³biogas/ kg COD removed) OLR (kg COD/ (m³ day)) AnMBR for the treatment of cheese whey aimed to recover water and energy RESULTS AND DISCUSSION CW CW + CM Time (d) CW CW + CM , , , ,7 0, , , , , ,1 0 0, Time (d) Biogas quality 51-73% Methane yield 0.26 ± 0.12 m³ CH₄/kg COD removed Organic Loading Rate (OLR) along operation OLR from 1.2 to 8.4 kg COD/m³day OLR from kg COD/m³day reported by Saddoud et al COD removal 78-99% Biogas production ( ) and biogas production per COD removed (Δ) Potential average energy production 2.4 kwh/kg COD removed 2.02 kwh/kg COD removed reported by Van Zyl et al

12 NaOH flow (g/day) meq NaOH/g COD AnMBR for the treatment of cheese whey aimed to recover water and energy RESULTS AND DISCUSSION NaOH for ph control used along operation. NaOH consumption (g/day) ( ) and NaOH consumption per COD removed (meq NaOH/g COD) (Δ) CW CW + CM Time (d) 12

13 RESULTS AND DISCUSSION Permeate composition according to feed characteristics Spanish RD 1620/2007 limits for water reuse Cheese whey Cheese whey : cow manure (3:1) For industrial cleaning purposes For irrigation purposes ph uph 7.5 ± ± Electrical conductivity ms/cm 14.8 ± ± TSS mg/l 79.3 ± ± VSS mg/l 69.1 ± ± Alkalinity mg/l 5220 ± ± VFA mg/l 4110 ± ± COD mg/l 3760 ± ± N total mg/l 235 ± ± N Kjeldhal mg/l ± P total mg/l ± Turbidity NTU 144 ± ± Escherichia coli cfu/100 ml 8.9E+04 ± 9.9E+04* < ⁴ 100 Intestinal nematode eggs eggs/l < 1 < [1] Legislation limits for water reuse in industry with cleaning purposes or process water, except for food industry. [2] Irrigation of crops with water irrigation system that allows direct contact of regenerated water and edible parts for human consumption in fresh. 13

14 E. coli concentration (cfu/100 ml) AnMBR for the treatment of cheese whey aimed to recover water and energy RESULTS AND DISCUSSION E. coli concentration in different process stages 1,00E+07 1,00E+06 1,00E+05 1,00E+04 1,00E+03 1,00E+02 1,00E+01 1,00E+00 Cheese whey Cow manure Anaerobic sludge Permeate 14

15 ph Saturation Index (SI) AnMBR for the treatment of cheese whey aimed to recover water and energy RESULTS AND DISCUSSION Turbidity assessment ph increase in permeate Salt saturation indexes of saturated phases 8,6 8,4 8,2 8 7,8 7,6 7,4 7,2 7 6,8 0:00 1:12 2:24 3:36 4:48 6:00 Time (h) Aragonite (CaCO₃) Calcite (CaCO₃) Dolomite (CaMg(CO₃)₂) Phases balanced in the reactor Hydroxyapatite (Ca₅(PO₄)₃OH) Phases balanced with the atmosphere Turbidity related to ph Target ph Conductivity (ms/cm) Turbidity (NTU) g HCl/m³ < 15 NTU >200 NTU ph ph ph

16 CONCLUSIONS TSS removal up to 99% High COD removals and high energy recovery could be obtained Higher OLR should be tested to assess the maximum treatment capacity of the technology. Regarding parameters regulated by RD1620/2007 intestinal nematode eggs and E. coli were within the limits of water reuse for industrial cleaning purposes, permeate turbidity and permeate suspended solids depended on inorganic precipitation after permeate being in contact with air. Further permeate treatment was found necessary. Salt precipitation was avoided by decreasing permeate ph, however, it implied high chemical consumption and increase in permeate electrical conductivity. 16

17 PILOT PLANT Biogas pipes Submerged flat sheet membrane module Control unit Feed solution: Cheese Whey Chemicals Bioreactor Permeate Water separator tank Gas blower/diffuser 17

18 PILOT PLANT MAIN RESULTS - Bad air scouring of the membrane - Lack of pump control at the beginning of the filtration cycles - Quick decrease of permeability - Low permeability did not permit high OLR - The potential of the technology could not be tested 18

19 PILOT PLANT MAIN CONCLUSIONS Cheese whey has high potential for being treated by AnMBR technology and producing a reclaimed water effluent that can be reused. AnMBR technology has great potential but needs to be optimized; especially in submerged membrane configuration. The submerged membrane AnMBR implies a lower investment cost but faces serious operative problems. It is crucial to optimize the membrane filtration step so that the permeability does not become the limiting factor of the technology. 19

20 Thank you Judit Ribera Pi 20