THROUGH HYDROGEN PEROXIDE UTILIZATION. James T. Swicegood Senior Technical Service Specialist Chemical Products Group FMC Corporation

Transcription

1 POLLUTION SOURCE REDUCTION IN DENIM WET PROCESSING THROUGH HYDROGEN PEROXIDE UTILIZATION -3 James T. Swicegood Senior Technical Service Specialist Chemical Products Group FMC Corporation

2 -1- A. INTRODUCTION PURPOSE AND SCOPE OF PRESENTATION 1. To describe current denim wet processing practices. 2. To review selected pollution terms and standards relevant to denim wet processing. 3. To review hydrogen peroxide's traditional role in waste water treatment. 4. TO discuss pollution source reduction and potential environmental improvements obtainable by using hydrogen peroxide.

3 I ht I E 0 v) w v) v) w U 0 a pc!+ w B u o Lc 4 U m u m O E sr E o 7 - C 4 d) a 4 W E E n z 0 z 0 n z 3 0 a W s u 2 m H X

4 U.S. COTTON CONSUMPTION AND DENIM'S SHARE (MILLIONS OF BALES) TOTAL DENIM % Le

5 BLUEJEANS CURRENT ANNUAL PRODUCTION MILLION PAIRS 0 2 PAIRS + PER U.S. CITIZEN n MILLION SQ. YARDS - If OZ./YD. AVE MILLION LES. OF FABRIC IN BLUEJEANS 3

6 i " TERMINOLOGY (SPECIFIC INDUSTRY VERNACULAR) a. Desizing--conventional or with stones b. Hand -- "feel" of garment, indication of desize effectiveness c. Stonewash -- can be used to specifically or collectively d. Acid wash, frost,ice, blizzard, etc. -- styling appearance caused by breakdown of indigo dye e. Anti-chlor -- sometimes used to include neutralization of permanganate f. Bleach, brighten -- increase contrast between dyed and stripped areas

7 , n ~ ~ ~ ~ ~ ~ ~ ~ ~ N G n GOODS FLOW COMPARISON -3 TmD I TI ONAL 1 YARN DYE WEAVE FINISH TEXTILE MILL 1. STONEWASHING YARN DYE NEAVE FINISH CONVERTER SEW INTO JEANS SEW INTO JEANS 1 WHOLESALEPETAIL STONEWASH BLEACB OVERDYE 1.

8 -7-4. CONVENTIONS: ASSIGNED DEFINITIONS a. Stonewashing--may be used as collective noun to refer to bluejeans wet processing; its more restricted sense refers to the use of stones to abraid, break hand, etc., without chemical bleach agent. b. Neutralization -- refers to either the anti-chlor after sodium hypochlorite treatment, or treatment after potassium permanganate decolorization. c. Top-brightening -- the final wet treatment to highlight the decolorized areas and maximize contrast with the remaining indigo.

9 L -8- C. REVIEW OF POLLUTION INFORMATION 1. DEFINITIONS OF COD, BOD, IOD a. b. C. d. COD -- the amount of oxygen required to oxidize both organic and oxidizable inorganic cmpds by chemical oxidizing agents. BOD -- the amount of oxygen required by aerobic bacteria to stabilize organic waste in solution. BOD-5 is usually considered to be about 68% of ultimate BOD for waste treatment. IOD -- immediate oxygen demand--the quantity of oxygen utilized by an industrial waste in excess of that normally measured by using standard laboratory methods, expressed in mg/l. cod:bod RATIO -- normally 2.5:l to 5.0:l for textile wastes; higher ratios may indicate poor biodegradability. BOD alone may not be an adequate indicator.

10 t TYPES OF POLLUTION -many ways of classifying wastes: a. Offensive, hazardous, toxic b. Air-borne, water-borne, surface c. Short term vs. Long term Ex.-low BOD now vs. high aquatic toxicity later-oxalic acid, low BOD, high toxicity a

11 TYPICAL MUNICIPAL DISCHARGE LIMITS & CONSIDERATIONS a. Discharge Limits: Parameter. Surcharge Maximum BOD-5 300mg/L 60 Omg/L COD O&G TSS PH c1 5Omg/L (0.5 to O.lmg/L expected?) City of Raleigh Limits: BOD COD TSS PH b. City of Raleigh has limit on IOD 'I Prohibited substances enumerated:... it shall be unlawful to discharge those [wastes] haveing an immediate oxygen demand of more than 5.Omg/L.

12 SOURCE REDUCTION OF POLLUTANTS -* a. b. C. d. e. f. 9- h. Raw material control Conservation/optimization - of chemicals Process modification Chemical substitutions Equipment modification Maintenance procedures Housekeeping Waste recovery (for reuse/recycle) I * from Pollutant Source Reduction; Prof. Brent Smith, NCSU (ADR-Mar 1989) Underlined methods applicable to this presentation.

13 -12- D. PEROXYGENS: HISTORICAL USE IN WASTE WATER AND TEXTILE TREATMENT 1. TEXTILE TREATMENTS WITH HYDROGEN PEROXIDE a. Bleach b. Desize c. Formaldehyde scavenger CH20 + 2H H20 +C02 d. Anti-chlor

14 WASTE WATER TREATMENTS WITH HYDROGEN PEROXIDE a. Chlorine compounds NaOCl + H202* NaCl + H20 + O2 b. Sulfur compounds -- including thiosulfates, H2S, sulfites H2S + H202 c+ 2H20 + S NaHS03 + H202-4 NaHSOq + H20 c. Phenols a.y H202---) 6C H 20 d. BOD/COD --shock loads, causing sudden severe drop in disolved oxygen can be quickly restored. e. Bulking control -- filamentous bulking, as well as other forms are treatable with hydrogen peroxide.

15 -14- E. PEROXIDE AS REPLACEMENT FOR SELECTED STONEWASHING CHEMICALS 1. DESIZING a. Size represents largest single group of chemicals used in textile industry b. Starch/enzyme desizing: produces 67 lbs of BOD/1001bs of fabric. 10gal. water/lb. fabric c. Desizing can contribute 50% of total BOD loading I

16 t -15- DESIZING CURRENT PROCESS IN STONEWASHING INDUSTRY: Enzymes 1) alpha amylase enzymes break only the alpha 1--4 linkages of starch, attacking in a random manner, thus producing water soluble dextrins and sugars--from Gist-Brocades Technical Bullet in 2) procedes: starch} dextrine) maltose) glucose; last two are soluble

17 L JH Figure 1 Figure 2 \ \ i \'., i \ I..! i The starch consists of two different polysaccharides. About 25% of the starch consists of amylose, in which about 900 to 1700 molecules form a long unbranched chain. About 75% of the starch consists of amylopectin, which is composed of giant branched molecules built up from about 900 to 1500 glucose molecules. These giant molecules are branched on an average at every 25th glucose unit.

18 -17- DESIZING RECOMMENDED FOR REDUCTION OF SOURCE POLLUTION: HYDROGEN PEROXIDE Forms dialdehyde) alkali breaks 1-4 soluble carbohydrate linkage, forming water ADVANTAGES: 1) Starch reaches stream in more completely oxidized form, creates less BOD demand 2) Excess peroxide contributes oxygen to stream

19 $ =s 0 & = th..c c z

20 -19- POTASSIUM PERMANGANATE NEUTRALIZATION CURRENT PROCESS: With sodium bisulfite/metabisulfite 1) 1,000 ppm sodium bisulfite will produce l2lmg/l BOD, 15lmg/L COD 2) Creates odor problems around workplace 3) Reducing agent; creates strong IOD which does not show up in BOD tests

21 t -20- POTASSIUM PERMANGANATE NEUTRALIZATION CURRENT PROCESS: With hydroxyl amine sulfate 1) Contributes to BOD 2) Has some objectionable odor 3) Some workers report skin sensitivity I

22 il -21- POTASSIUM PERMANGANATE NEUTRALIZATION RECOMMENDED: HYDROGEN PEROXIDE SYSTEM Contributes oxygen to system Has no significant odor Easily handled liquid System has enhanced neutralization properties Excess peroxide adds oxygen to system; lessens BOD, odor problems downstream Adds no harmful or undesirable compounds to system; only oxygen and water

23 SODIUM HYPOCHLORITE ANTICHLOR TREATMENT CURRENT PROCESS: a. sodium bisulfite/metabisulfite 1) 1,000 ppm sodium bisulfite will produce 12lmg/L BOD, 15lmg/L COD 2) Creates odor problems around workplace 3) Reducing agent; creates strong IOD which does not show up in BOD tests b. hydroxyl amine sulfate 1) Contributes to BOD 2) Has some objectionable odor 3) Some workers report skin sensitivity

24 -23- SODIUM HYPOCHLORITE ANTICHLOR RECOMMENDED: HYDROGEN PEROXIDE Contributes oxygen to system Has no significant odor Easily handled liquid System has enhanced neutralization properties Excess peroxide adds oxygen to system; lessens BOD, odor problems downstream Adds no harmful or undesirable compounds to system; only oxygen and water

25 t L) TOP- BRIGHTENING CURRENT PROCESS: a. sodium hypochlorite 1) tends to yellow on ageing 2) must be antichlored 3) chlorine in air can contaminate, yellow other garments in storage, transit b. sodium perborate 1) more expensive form of available oxygen than hydrogen peroxide 2) powder form

26 -25- TOP-BRIGHTENING RECOMMENDED: HYDROGEN PEROXIDE 1) Gives more permanent white 2) Compatable with many optical brighteners 3) Liquid form, easily used 4) Contributes oxygen to system 5) Lessens probability of BOD, odor problems downstream 6) No undesirable by-products 7) Historically textile whitener of choice

27 -26- F. SUMMARY AND CONCLUSIONS 1. EFFECTIVENESS OF HYDROGEN PEROXIDE a. As treatment component Equivalent or superior in all treatments b. As environmental benefactor Uniquely benevolent to the workplace and downstream environment 2. SAFETY OF HYDROGEN PEROXIDE a. Handling -- Has been used by traditional textile wet processing industry for over 50 years with outstanding safety record. b. Environmental --In addition to neutralizing many harmful compounds, hydrogen peroxide in excess in ponds is not toxic: 1) 100% fish survival after 96 hours 2) 4Omg/L H202 had no effect fingerling trout after 48 hours exposure 3. FUTURE WORK -- Investigations continue on additional processes and techniques for use in the denim wet processing industry at at FMC s Research and Development Center in Princeton, New Jersey -