Ph.D. Ewa PołomInstitute of Chemical Engineering and Environmental Protection Processes

THE UTILISATION OF WASTE LACTOSE

WITH MEMBRANE TECHNIQUES USAGE

Plan of presentation

1. Introduction2. Integrated systems of environmental protection 3. Whey as a source of valuable products4. Membrane techniques proposed for lactic acid LA,

manufacturing 5. Zr(IV)/PAA Dynamically formed membranes DMF6. The scheme of the experimental set-up7. Statistical examination of experimental results7. Conclusions

Introduction

productionprocess

water

raw materials

energy

air pollution

main product

solid wastes

liquid wastes

POLLUTION PREVENTION

cleaningstrategy

cleanerstrategy

re-use recycling energyrecovery

deposition

Integrated systems of environmental protection

Diary industry main products

cheeses

yoghurts

skim milk

Main waste from food processing

whey

lactose5%

proteins0,8%

minerals and vitamins 0,5%

fats 0,3%

lactic acid0,2%

Lactic acid LA stereoisomers

Possibilities of LA obtaining :1. Chemical synthesis from oil-based non renewable

resources2. Biotechnical processes based on fermentation of

industrial wastes

The main steps in the process of waste lactose conversion to LA or ethanol

Product separation/purification

Product concentration

Sugar conversion

Feedstockpreparation

The membranes techniques proposed for LA manufacturing by waste lactose fermentation

1. Prefiltration of solutions before fermentation processes2. Selection of lactic acid from post -fermentiation solution3. Conversion of lactic acid salts into lactic acid4. Purification and concentration of lactic acid solutions

Membrane technique Stage 1 Stage 2 Stage 3 Stage 4

Microfiltration, MF v v

Ultrafiltration, UF v v

Nanofiltration, NF v

Reverse osmosis, RO v

Liquid membranes, LM v

Membrane extraction, EM v

Electrodialysis, ED v

MF+ ED V V

UF + ED V V

UF+ MF + ED v V V

EM + ED v v

Fermentation

UF MODULE

ED UNIT

lactic acid

sodium lactate

post fermentaive solution

lactose

+ lactic acid bacteria

Integrated scheme of LA production with product neutralisation

The conception of LA production from whey with continuous product disposal

The characteristic of Zr(IV)/PAA dynamically formed membranes DFM

Membrane Support Gel-layer Pore radius*/

layer thickness**

MF, Ti (IV) Stainles

steel tube

TiO2 0.03 – 0.05 m*

UF, Zr (IV) MF membrane

ZrO(OH)2 10 m**

NF,

Zr (IV)/PAA

UF membrane

PAA 2 m**

DF MEMBRANES Zr(IV)/PAA EMS PHOTOS

a) Top view of NF DFM Zr(IV)/PAA surface of PAA

layer

b) Cross- section of two NF DFM Zr(IV)/PAA layers:

ZrO(OH)2 and PAA

K.S. Menon, Thesis, Clemson University, Clemson 1988

DF MEMBRANE Zr(IV)/PAA

The scheme of the experimental set-up

´

Statistical examinations of NF LA solutions experimental results

r=0,35–0,05x1+0,104x2+0,08x3–0,09x4+0,14x1x4–0,044x2x4+0,03x1x2x4+0,03x2x3x4

r=0,49–0,027x1+0,11x2+0,1x3–0,077x4+0,135x1x4–0,044 x2x4–0,061x32–0,077x4

2

(1)

(2)

Forms of obtained polynomial models:

Symbol Parameter description Range of parameter

x1 Cross flow velocity 1.0 – 2.6 m/s

x2 pH of feed solution 4.0 – 8.0

x3 Pressure difference across membrane surface

1.4 – 5.5 MPa

x4 Concentration of LA in the feed solutions

0.02 – 1.0 mol/l

Independent variables description

x1 u = 1,0 [m/s]

x2 pH = 8,0

x3 p = 5,52 [MPa]

x4 cLA= 0,02 [mol/l]

rmax = 0,82

x1 u = 2,6 [m/s]

x2 pH = 4,0

x3 p = 1,42 [MPa]

x4 cLA= 0,02 [mol/l]

r min 0,02

Values of parameters allow to obtain rmax

Values of parameters allow to obtain rmin

Influence of NF process parameters on LA DFM Zr(IV)PAA selectivity

• Fermentation of waste lactose connected with lactic acid manufacturing is the best way of whey utilisation which corresponds to the integrated systems of environmental protection rules

• Employing pressure membrane techniques in utilisation of whey process brings profits from both: environmental and economical points of view

• Zr(IV)/PAA DFM can be use in LA separation from fermentative solutions and purification of selected product.

Conclusions