General characteristics of textile sector and wastewater reuse potential possibilities

Transcription

1 General characteristics of textile sector and wastewater reuse potential possibilities Simona Vajnhandl 1, Alenka Majcen Le Marechal 1, Davide Mattioli 2, Selene Grilli 2 1 University of Maribor, Faculty of Mechanical Engineering, Department for Textile materials and Design 2 ENEA, Bologna, Italy AquaFit4use End Congress 8-9 May, 2012, Bruges, Belgium

2 Summary Current situation of textile sector Water key problems Case studies in AquaFit4use-Tekstina, Svilanit Proposed solutions for water reuse AquaFit4use contributions 2

3 Current situation of textile sector In the face of intense global competition European textile and finishing companies are increasingly turning to research and innovation, which can ensure sustainable competitiveness. Textiles are (re-)discovered as highly engineered high performance materials with significant long term growth potential (textile solutions replace traditional materials and technologies in many areas like transport, construction, energy, healthcare, environment). Mainly represented by SMEs 3

4 Water key problems IPPC Directive (abandoning of hazardous chemicals, introduction of equipment using less water, heat recuperation, water and wastewater management is still a bottleneck). The textile finishing industry is a large fresh water consumer wastewater producer. Processes using water are: desizing, scouring, bleaching, mercerizing, dyeing example printing, washing, neutralization and salt baths. 4

5 example 3000 L soft water Steam Electricity Step 1-dyeing T1=25 C.; t1=min.. Heating min/40 C T2=40 C, t2= 15 min.. T3=40 C,t3= 20 min T4=40 C,t4= 32 min T5=40 C,t5= 10 min T6=40 C,t6= 30 min T7=40 C,t7= 15 min heating 2 C/min/60 C T8=60 C,t7= 50 min Indirect heating 0,1 g/l Albatex FFC 50 g/l Sodium chloride 1,2 % Novacron orange FN-R 2,26 % Novacron rot FN-R 5 g/l sodium carbonate 1 ml/l sodium hydroxide Discharge 3000 L soft water Electricity Step 2-rinsing Filling cold water T1=25 C.; t1=10'min No heating Discharge 5

6 example 3000 L soft water Electricity Step 3 - rinsing Filling warm water T1=50 C.; t1=10'min emptying some warm water and filling new one No heating Discharge 3000 L soft water Electricity Step 4 - rinsing Filling cold water T1=25 C, t1=8'min emptying some cold water and filling new one No heating Discharge 6

7 example 3000 L soft water Steam Electricity Step 5 - soaping (filling with warm water); heating/95 C T1=95 C,t1= 20min Cooling cca 3 min/80 C Indirect heating 1,5 ml/l Lavan RF Discharge 3000 L soft water Electricity Step 6 rinsing Filling warm water T1=50 C t1=10'min (circulation).. T2= 50C t2=10'min Emptying some warm water and filling new No heating Discharge 7

8 example 3000 L soft water Steam Electricity Step 7 rinsing filling warm water T1= 50 C; t1= 1min Heating min/80 C.. T2=80 C..; t2=10'min Indirect heating Discharge 3000 L soft water Electricity Step 8 rinsing Filling warm water T1= 50C t1=10'min (circulation).. T2= 50C t2=10'min Emptying some warm water and filling new No heating Discharge 8

9 example 3000 L soft water Steam Electricity Step 7 rinsing filling warm water T1= 50 C; t1= 1min Heating min/80 C.. T2=80 C..; t2=10'min Indirect heating 0,5 ml/l Acetic acid 80% 2,5 % Tubingal ASW 1,0 % Sevofix FFK Discharge Water, energy, time consuming multistep processes, producing complex wastewater with variable composition As an average, 60 to 90 % of the total water consumption is for rinsing purposes. 9

10 Water key problems In Europe, 108 million tons of wastewater is produced on a yearly basis and 36 million tons of chemicals and auxiliaries have to be removed from the textile wastewater. Wastewater is heavily charged with unconsumed dyes (up to 50%), salts, acids, bases, surfactants, metals, organics, biocides, toxic persistent organic pollutants, etc.). The amount and the composition of wastewater vary significantly depending on the processed fabric, type of the process, the equipment used and the prevailing management philosophy regarding water use. Changes of machines, used chemicals or other characteristics of the processes also alter the nature of the generated wastewater. 10

11 Water key problems Generated wastewater include cleaning, process, cooling and storm water Neutralization of ww local municipal wastewater treatment plant No reuse Scouring, dyeing, printing and finishing are processes generating the majority of textile wastewater (many rinsing sequences after each step). Typical cotton batch dyeing operations use salts in the range of % weight of dyed materials. 11

12 Water key problems Significant variation of ecological parameters of individual waste effluents ph 2-13 COD (g/m -3 ) TSS (g/m -3 ) Turbidity (NTU) Conductivity (ms/cm) Color-absorbance average Whatisthebestsolution? Which wastewater treatment technologies? Howtoimplementwaterreuse? 12

13 Case studies in AquaFit4Use -Tekstina, Svilanit Fresh water - Towards a new concept of ww treatment - streams separation Softening Process water Cooling water Textile finishing processes Concentrated WW (printing, finishing) Low concentrated WW (washing, rinsing) Heat recuperation heat Evapoconcentration Water for reuse AOP prefiltration UF;NF Incineration or use in other domains Concentrate 13

14 Case studies in AquaFit4Use -Tekstina, Svilanit Machinery can be used for different textile processes or specific ones discharges are very diverse in pollution level Separation of waste streams can base on: I) process machinery or II) on line monitoring of relevant parameters 14

15 Case studies Streams separation I Primary water Pretreatment Mixing tank M1 M2 M3 M4 E1 E2 E3 E4 Treatment for low conc. effluents Treatment for high conc. effluents 15

16 Case studies I) Good separation based on machinery allows to separate significant pollutant loads in a very small volume Annual volume Tekstina Annual COD volume load Tekstina YD1-4 Jig1 Jet1-2 Wash1 Print1 Imp. Bleach Foulard Stenter1-2 YD1-4 Jig1 Jet1-2 Wash1 Print1 Imp. Bleach Foulard Stenter1-2 3 machinery present 1% of total V and 50 % of total COD 16

17 Case studies Streams separation II Primary water Pretreatment Mixing tank M1 M2 M3 M4 E1, E2,..En E1, E2,..En E1, E2,..En E1, E2,..En UF NF or AOP High conc. effluents treatment Discharge 17

18 Case studies II) Monitoring based separation is a good solution - Dual wastewater network and the monitoring devices are needed Annual volume Svilanit Annual COD load Svilanit Low cont. Low cont. High cont. High cont. 18

19 Proposed solutions for water reuse For Tekstina 4 reuse scenarios were proposed, based on machinery or monitoring separation of waste streams For Svilanit 1 scenario was proposed, based on monitoring separation of waste streams For each scenario we calculated: - wastewater recycled, - wastewater discharged, - fresh water consumption reduction 19

20 Proposed solutions for water reuse Type of WW streams Machinery separation Monitoring separation 1. solution 2. solution 3. solution 4. solution High conc. Evapoconcentration Evapoconcentration Medium-high Conc. WWTP (on site or centralized) WWTP (on site or centralized) Low-medium Conc. MBR 45 % of the WW treated by MBR is recycled MBR + NF 85 % permeate recovery considered Low Conc. UF(69%) + NF 90%UF & 85%NF permeate recovery UF (69%) + AOP 90% UF permeat recovery, all to AOP Actual fresh water consumption m 3 /year m 3 /year Possible fresh water reduction to m 3 /year m 3 /year m 3 /year 20

21 AquaFit4use contributions Providing know-how related to water and wastewater management for SMEs Proposition of applicable solutions for wastewater treatment and reuse (small scale tailor made conventional treatment technologies) 21

22 THANK YOU FOR YOUR ATTENTION 22