Influence of Hydrophobe Type and Extent of Branching on Environmental Response Factors of Nonionic Surfactants

.a .. 2 ? .. r’ * 33/3 S€H-S?41 Technical Bulletin /J &f= 3 Shell Chemical Company

L. Kravetz, J. P. Salanitro, P. B. Dorn and K. F. Guin

Shell Development Company Westhollow Research Center P.O. Box 1380 Houston. Texas 77251

Presented at the 81st American Oil Chemists’ Society Annual Meeting, April 22-26, 1990 Baltimore, Maryland, and reprinted with permission JAOCS, Vol. 68, No. 8 (August 1991) A number of ethoxylated nonionic surfactants dif- acceptable biodegradability in order to meet efflu- fering in hydrophobe branching and chain lengths ent regulatory criteria. have been evaluated for environmental responses. This paper discusses an environmental re- Screening biodegradation tests show those non- sponse study of three of the major types of surfac- ionics having more than one methyl group per hy- tants derived from linear primary alcohols, highly drophobe degrade considerably slower than those branched primary alcohols and branched nonyl- having less extensive branching. Continuous phenols. Nonionics derived from the nonylphenols flow-through activated sludge tests, simulating ac- have also been studied exten~ively.~~~~-~~Each of tual waste treatment, show the more highly these nonionic classes is a complex mixture of ho- branched nonionics biodegrade more slowly and mologs and isomers. Representative structural less extensively than do those with less hydro- features are shown in Figure 1. The study encom- phobe branching. In addition, treated effluents passes ultimate biodegradability to COP and H20, originating from influents containing the more high- primary biodegradability in laboratory tests de- ly branched nonionics tend to be more surface ac- signed to simulate large-scale sewage treatment tive and more toxic to aquatic species than those in summer and winter, aquatic toxicities of sewage originating from influents containing surfactants effluents resulting from biotreatment of the three with less hydrophobe branching. Under conditions surfactant types, and identification of surfactant simulating plant stress, such as high surfactant biodegradation intermediates. concentrations in the influent or low temperature, In addition to ethoxylates of the linear and biodegradation of the highly branched nonionics branched alcohols, the alcohol sulfates (AS) of was considerably less extensive while biodegrada- these hydrophobes were also included in several tion of the linear nonionics was not affected to any of the biochemical oxygen demand (BOD) tests. measurable degree compared to more normal operating conditions. Experimental Synthesis of Alcohol Ethoxylates (AE) and Introduction Alcohol Sulfates (AS) Surfactants are used increasingly in household AE synthesis was performed by ethylene oxide cleaning products, personal care and a variety of addition to the appropriate alcohol in an autoclave industrial and institutional applications.' Owing to using conventional KOH catalysis. A modification the tendency of these surfactants to foam and ex- of a chlorosulfonic acid procedure was used to hibit toxicity to aquatic organisms at relatively low prepare AS.20 In this modification, nitrogen gas concentrations, they must be removed prior to en- was dried by passing through a 20 cm long x 3 tering receiving waters in order to meet regulatory cm wide glass column containing Ascarite. To en- requirements. Secondary waste treatment, em- sure an essentially water-free alcohol reactant, the ploying aerobic biodegradation, is the most widely dried nitrogen was bubbled through 100 "ole of used approach to reducing the undesired proper- appropriate alcohol reactant dissolved in 50 ml of ties of organic materials, like surfactants, which methylene chloride for 15 minutes prior to addition enter domestic waste treatment plants. In this ap- of chlorosulfonic acid. Chlorosulfonic acid at proach, bacteria provide enzymatic systems which 1.05:l molar ratio was then added dropwise with utilize oxygen to convert organic materials to C02, stirring with the nitrogen sparge tube placed above H20 and cellular mass. The process is complex the surface of the liquid reaction medium. The ad- with biodegradation rate dependent on the struc- dition of chlorosulfonic acid was controlled at a ture of the organic material. Alcohol-based surfac- rate which maintained the exothermic reaction tants having essentially linear hydrophobes have within a temperature range of 30-35 OC. After ad- been shown in many extensive studies2-9to biode- dition of chlorosulfonic acid, the nitrogen sparge grade rapiaiy to produce non-foaming non-toxic tube was piacea beiow the surface of ihe reaciion products in treatment plant effluents. However, mixture with N2 sparging continuing for 30 minutes biodegradation of those alcohol-based surfactants under stirring using external heating to maintain a having highly branched hydrophobes has been 30-35 OC temperature. This permitted removal of studied less extensivelylO~ii than the linear surfac- essentially all the HCI gas which had formed. The tants, since demand for the highly branched sur- resulting AS in the acid form were neutralized with factants has not been as great as those based on aqueous NaOH to produce 25% active AS at pH = linear hydrophobes. All surfactants must show 8-9.

2 Nuclear Magnetic Resonance (NMR) Analysis Gas Chromatography (GC) and High for Branched Hydrophobes Performance Liquid Chromatography (HPLC) 3 Carbon-13 NMR analysis for branching in alcohols For Polyoxyethylene (POE) Distributions and AE’s was performed on a Bruker AM-500 POE chain lengths from 1-6 were determined us- spectrometer. A 50% volume solution is made with ing a Varian 3500 capillary g.c. fitted with a 15 the sample and deuterochloroform solvent which meter narrow bore DB-5 column. AE’s were in- contains 0.2 molar TEMPO relaxation reagent. jected as their trimethylsilyl ether derivatives. Pure Two milliliters are placed into a 10 mm NMR tube. dodecyl AE’s having specific POE chain lengths The NMR acquisition is done using a 45 degree ranging from 0-8 were used as calibration stan- pulse with a 10 second relaxation delay and 2000 dards. Pure decyl alcohol was used as internal scans are acquired for each experiment. Two ex- standard. Detection was by flame ionization. A periments are required for each analysis. They are Varian 5500 HPLC was used to determine POE a normal NMR acquisition with NOE (Nuclear chain lengths greater than 5. AE’s were injected Overhauser Enhancement) suppression and a as their phenylurethane derivatives into a silicon j-modulated spin echo experiment (JMSE) to iden- column with a ternary gradient system composed tify the carbons according to the number of pro- of methanol, isopropanol and acetonitrile. Detec- tons attached. Spectral editing is then used to tion was by UV at 254 nm. Data from the gc and identify and quantify the methyl groups. HPLC were combined and POE distributions cal- culated via a spreadsheet program using a PET Gas Chromatography/Mass Spectroscopy 2001 computer. (GC/MS) for Hydrophobe Carbon Number Distribution (CND) Surfactant Substrates GC/MS was used to determine CND’s for highly Nonionic and anionic surfactant substrates used in branched alcohols, since GC and liquid chromatog- the biodegradation and/or aquatic toxicity tests raphy were unsuccessful due to extensive branch- discussed below are listed with their major struc- ing which led to significant carbon number overlap. tural features in Table 1. They will be referred to GC/MS data were obtained using the VG-Tritech by the acronyms listed in column 2. Parenthetical TS-250 GC mass spectrometer. Trimethylsilyl suffix letters L and B refer to essentially linear and (TMS) ether derivatives of the branched alcohols highly branched, respectively. Methyl group were prepared using n,o-bis (trimethylsilyl) triflou- branching is defined by the number of methyl roacetamide (BSTFA) with 1% trimethylchlorosilane groups pendant to the alkyl chain and they are (TMCS). This catalyzed formulation was used to si- listed as internal methyl groups/hydrophobe. lylate any slightly hindered hydroxyls which might be present and is stronger than BSTFA alone. Biodegradation via Biochemical Oxygen BSTFA reacts quantitatively with free OH-groups to Demand (BOD) Tests form stable TMS derivatives for GC analysis. Re- BOD tests were run by Edna Wood Laboratories, placement of the acidic hydrogen with Si(CH3)3 in- Inc., Houston, Texas using an established test pro- creases the molecular weight of the free alcohol by cedure.21 For BOD studies, bacterial inocula had 72 daltons. For example, the molecular weight of a been obtained from a seed which was unaccli- C12 alcohol (M.W.186) is shifted to a molecular mated and different from that used for the C02 weight of 258. The molecular ion is frequently weak evolution tests. BOD measurements were made or absent in the electron impact mass spectrum of by titrating for dissolved oxygen using the azide aliphatic trimethylsilyl ethers. However, the intense modification of the Winkler method. Chemical oxy- (M - CH3)+ peak can be used for purposes of mo- gen demand (COD) measurements were made lecular weight determination and quantification. The using the silver sulfate-mercuric sulfate modifica- spectrum of the trimethylsilyl ether derived from a tion of the dichromate method. C12 alcohol (M+ = 258) would therefore exhibit an intense ion occurring at m/z 243. A normalized per- Ultimate Biodegradation via C02 Evolution cent carbon number distribution was obtained by Batch Tests summing the characteristic (M - CH3)+ fragment C02 evolution resulting from aerobic microbial at- ions, in the appropriate GC retention time window, tack on surfactants was performed using an for each carbon chain length. OECD modification22 of the Sturm Test.23 Closed

3 one liter biotreatment units with 500 ml liquid vol- it is instructive to characterize branching by the ume contained Sturm mineral salts solution, 10, number of internal methyl groups per hydrophobe 20 or 50 mg/l surfactant or sodium benzoate (posi- as determined by NMR. In a comparison of the tive control), antifoam agent and composited biodegradation of linear with branched alcohols, mixed liquor suspended solids (MLSS) from accli- Swisher28 indicated a single internal methyl group mated activated sludge cultures. Activated sludge has no appreciable effect on biodegradation rate was obtained from a Houston domestic waste compared to a 100% linear alcohol. However, in- treatment plant. Viable bacterial counts were corporation of a second methyl group decreases 107-l 08/ml initially and 106-1 07/ml after the 28-day biodegradation rate significantly, particularly if the test. second methyl group is located on the same carbon atom to produce a quaternary carbon Continuous Activated Sludge Biotreater Tests structure. These laboratory tests, designed to simulate the secondary treatment section of a full-scale sewage Biodegradation via BOD Tests treatment plant, have been described previ~usly.~~ The results of a 30-day BOD test using the Low temperatures simulating winter conditions C12-15AE-9(L), C13AE-7(B) and NPE-9(B) are were conducted in an environmental chamber shown in Figure 3. The linear AE biodegraded equipped with a refrigeration unit. A schematic of considerably faster and more extensively (88%) the bench-scale units is shown in Figure 2. compared to the branched AE (44%) and the branched NPE (31%). In this test, at least 50% Aquatic Toxicity Tests biodegradation is required in order to categorize Intact surfactants and effluents from biotreaters the test substrate as having “ready biodegradabil- degrading 50 mg/l surfactants at 25 OC were sub- ity” according to standards set by the Organization jected to acute and chronic aquatic toxicity testing for Economic Cooperation and Development using waterfleas (Daphnia magna) and fathead (OECD).29 minnows (Pimephales promelas) according to es- A comparison of the effect of hydrophobe chain tablished EPA procedure^.^^^^^^^^ Testing was length on the ultimate biodegradability of linear done by TRAC Laboratories, Inc., Denton, Texas. and branched AE’s as determined by BOD tests is shown in Figure 4. The linear AE’s again showed Primary Biodegradation much faster and more extensive biodegradation The extent of removal of intact surfactant (primary over 30 days than the highly branched AE’s. In biodegradation) in continuous activated sludge bio- addition, hydrophobe chain length appeared to treaters was followed by the cobalt thiocyanate ac- have a slight but perceptible effect on the linear tive substance (CTAS) procedure.27 An approxi- AE’s with the C~~,J~AE-~(L)biodegrading to 83% mation of the extent of surfactant primary bio- while the lower chain length C12-15AE-7(L) biode- degradation was also made by measuring foam graded at a slightly faster rate to 92%. In contrast, heights generated from 50 ml of effluent manually the C12AE-7(B) and C13AE-7(B) showed no ap- shaken in a stoppered 100 ml graduate cylinder. preciable differences in rate or extent of biodegradation. Results and Discussion Figure 5 shows 30-day BOD results for Chemical Structure of Surfactants C14,15AS(L) compared to branched C13AS(B). The Each nonionic ethoxylate shown in Table 1 was C14,15AS(L) biodegraded to near the theoretical found to contain an average of 7 or 9 (+/- 0.2) amount (98%) while the C13AS(B) biodegraded EO units/mole of alcohol or nonylphenol. Alcohol considerably less extensively (41Yo). These results sulfates contained 1-2% unreacted organic matter are qualitatively in line with literature values30 based on active matter present. Alcohol ethoxy- which show 30% biodegradation for a C13AS(B) lates (AE), alcohol sulfates (AS) and C12 linear and 86% biodegradation for a C11-15AS(L) in a alkylbenzene sulfonate (LAS) each contained hy- 20-day BOD test. drophobes of varying chain lengths as indicated. Approximately 20% of the essentially linear AE’s Ultimate Biodegradation via C02 Evolution derived from the C12-15 and c14,15 alcohols con- The results of a 28-day C02 evolution test using tained 2-alkyl monobranching - mostly methyl. initial surfactant concentrations of 20 mg/l are The highly branched C12 and C13 alcohols appear shown in Figure 6 for CQ-~~AE-~(L),C13AE-7(B) to have been derived from propylene oligomers. and NPE-9(B). The results are qualitatively similar /j The structural characteristics of the highly to those found in the BOD test (Figure 3) with the lin- branched surfactants are quite complex. However, ear AE biodegrading faster and more extensively

4 than the branched AE and NPE. Twenty-eight day occurred near 8 OC (Figures 14 and 15) indicating C02 evolution test results for these surfactants at biodegradation had slowed considerably for these varying initial concentrations (10, 20 and 50 mg/l) branched surfactants. In contrast, C12-15AE-9(L) are shown in Table 2 along with sodium benzoate showed no significant CTAS breakthrough even at added as a positive biodegradation standard. Sim- temperatures as low as 8 OC (Figure 13). ilar biodegradation patterns were observed for all Two additional observations of the physical con- concentrations with the linear AE showing consid- ditions of the biotreater units deserve mentioning. erably greater biodegradation than the branched 1. Those units treating the highly branched sur- nonionics. factants tended to foam and required period- ic addition of antifoaming agents, while little Continuous Activated Sludge Bench-Scale foam was observed in the unit treating the Biotreater Test linear surfactant. The foaming was worse Bench scale biotreater tests run at 25 simulat- OC when the branched surfactants were treated ing summer conditions were run in separate units under stress conditions, Le., at higher influ- with C12-15AE-9(L), C13AE-7(B), NPE-9(B) and a ent concentrations or at lower temperatures. sodium benzoate control. Bacterial inoculum in each unit was adapted to the appropriate surfac- 2. Increased solids carryover was periodically tant or sodium benzoate at increasing concentra- observed in the clarifier overflow for the tions (0-50 mg/l) over a period of 5-6 months. The branched surfactant units but not for the lin- minimum adaptation time for any given substrate ear surfactant unit. Solids carryover was concentration was 40 days. The lower concentra- worse when the branched surfactants were tions are similar to influent loadings from domestic treated at the higher influent loadings or at waste, while the higher concentrations are typical lower temperatures. The solids carryover is of influent loading from industrial waste. Operating probably due to the presence of significant parameters are summarized in Table 3. levels of surface active material in the Effluent CTAS values for each unit are shown in branched surfactant units. This surface active Fgures 7-9 for C12-l5AE-9(L), CI3AE-7(B) and material is likely due to blends of intact sur- NPE-9(B), respectively. Effluent foam heights for factant and their partially degraded metabo- these surfactants are shown in figures 10-12. lites. Movement of these surface active com- These CTAS and foam height primary biodegrada- ponents to the sludge/liquor interfaces likely tion criteria show the C12-15AE-9(L) unit yielded prevents good sludge flocs from forming and less intact surfactant in the effluent than the results in solids carryover into the clarifier. C13AE-7(B) and the NPE-9(B). The many CTAS The linear nonionic undergoes sufficiently and foam height peaks and valleys, particularly for rapid biodegradation and does not permit ac- the branched surfactants, are probably due to cumulation of surface active material which sludge desorption and sorption of intact surfac- can sorb onto sludge and interfere with sol- tants and/or their partially degraded metabolites as ids separati~n.~*v*~ fresh surfactant is continuously fed to the biotreaters. What is clear from these studies is that the Aquatic Toxicity Tests on Biotreated Effluents highly branched nonionics do not biodegrade as Acute and chronic aquatic toxicity test results for readily as the linear nonionics, particularly at the Pimephales promelas (fathead minnow) and higher influent concentrations. Daphnia magna (waterflea) exposed to intact sur- The continuous activated sludge biotreater re- factants used in the continuous biotreater studies sults discussed above are in line with the few con- (50 ppm at 25 OC) are listed in Table 4. It is ap- tinuous or semicontinuous activated sludge tests parent that the intact linear AE was somewhat reported for highly branched AE’s31332 under nor- more acutely and chronically toxic than the intact mal operating conditions. branched AE and branched NPE. However, Figure The results of operating under simulated winter 16 shows that acute toxicity was present only in conditions at 10 mg/l influent concentrations are the effluent from the NPE-9(B) unit (20-40% shown in Figures 13-15, for effluent CTAS re- LC-~O’S),indicating that the C12-15AE-9(L) and sponse of the C12-15AE-7(L), C13AE-7(B) and C13AE-7(B) surfactants had biodegraded to prod- NPE-9 units respectively. CTAS response for all ucts which were not acutely toxic. Effluent chronic three surfactant units were similar at 25 OC. As toxicity data, plotted in Figure 17, shows least tox- the operating temperature was lowered sequential- icity for the effluents from the C12-15AE-S(L) unit ly from 25 OC to 8 OC, significant CTAS break- and significant levels of toxicity for effluents from through for the C,3AE-7(6) and NPE-9(B) units the two branched surfactant units.

5 Correlation of Structure With Environmental 7Birch, R. R., hid. 67, 340 (1984). Response 8Steber, J., and P. Wierich, Tenside 20, 183 Those surfactants having more than one internal (1983). methyl branch per hydrophobe tend to biodegrade 9Watson, G. K., and N. Jones, Gen. Microbiol. slower than surfactants based on linear hydro- Quart., 6, 78 (1979). phobes. The lower aquatic toxicities shown by in- lopatterson, S. J., C. C. Scott, and K. B. E. Tuck- tact surfactants having more than one methyl er, J. Am., Oil Chem. SOC.44, 407 (1967). branch is offset by their slower biodegradability l1Schoberl, P., E. Kunkel, and K. Espeter, Ten- which tends to leave treatment effluents more tox- side 18, 64 (1981). ic than those derived from the more linear hydro- 12Brown, D., H. de Henau, J. T. Garrigan, P. Ger- phobes. ike, M. Holt, E. Kunkel, E. Matthijs, J. Waters, The mechanism for biodegradation of linear and R. J. Watkinson, Ibid. 24 (1987). AE’s is known to involve rapid cleavage of hydro- 13Borstlap, C., and C. Kortland, Feften, Sei- phobe from hydr~phile~~~~to produce non-toxic fen, Ansfrichm. 69, 736 (1967). products. For biodegradation of branched NPE’s, 14Lashen, E. S., F. A. Blankenship, K. A. Boom- the mechanism reportedly involves a slower step- an, and J. Dupre, J. Am. Oil Chem. SOC.43, wise shortening of the hydrophilic portion to yield 371 (1966). NPE’s with shorter POE chains.18~19~33For highly l5 Narkis, N., and M. Schneider-Rotel, Water Res. branched AE’s, the few reported mechanistic stu- 74, 1225 (1980). dies point to a POE chain shortening pathway 16Gerike, P., and W. Jasiak, Surf. Cong. No. 8, 7, similar to that for NPE.33134 The importance here 195 (1984). is that these NPE’s and AE’s with short POE l7Pitter, P., and T. Fuka, Env. Protec. Eng. 5, 47 chains may biodegrade more slowly and show (1979). greater aquatic toxi~ity~~r~~than their longer POE 18Kravetz, L., H. Chung, K. F. Guin, W. T. Shebs, chain precursors. Also, due to their hydrophobic and L. S. Smith, Household Pers. Prod. lnd. character they may tend to accumulate in effluents 19, 46 and 72 (1982). and on sludges and sediments.l 8924137 Analytical 19Rudling, L., and P. Solyom, Water Res. 8, 115 methodology to identify and determine AE and (1974). NPE metabolites on preserved sludges and efflu- 20Gilbert, E. E. and B. Veldhuis, J. Am. Oil Chem. ents from the continuous biotreater study is under- SOC.36, 208 (1959). way and will be reported at a later date. 21 Standard Methods for the Examination of Water and Wastewater, 16th Edition, Am. Publ. Health Acknowledgments Assoc., Washington, D.C. (1985). The authors are grateful to the following: L. A. 22 OECD Guidelines for Testing of Chemicals. The Diaz, C. M. Brunner and G. Langston (biodegrada- OECD Expert Group on Degradation and Accu- tion data), S. H. Evans (aquatic toxicity samples), mulation. Organization for Economic Coopera- J. E. Nkomo (CTAS and foaming), R. J. Blanco tion and Development, Paris (1981). and L. A. Gingrich (alcohol ethoxylation), T. D. 23Sturm, R. N., J. Am. Oil Chem. SOC.50, 159 Hoewing (alcohol sulfation), J. P. Cocchiara and J. (1973). G. Nowlin (GUMS) and R. W. Willson (NMR). 24Salanitro, J. P., G. C. Langston, P. B. Dorn, and L. Kravetz, Wat. Sci. Tech. 20, 125 (1988). References 25Peltier, W. H. and C. I. Weber, Measuring the Haupt, D. E., Tenside 6, 332 (1983). Acute Toxicity of Effluents to Freshwater and *Mann, A. H., and V. W. Reid, J. Am. Oil Chem. Marine Organisms, EPA 600/4/85/013 (1 985). SOC.48, 794 (1971). 26Horning, W. B. and C. I. Weber, Short-Term 3Huddleston, R. L., and R. C. Allred, /bid. 42 Methods for Estimating the Chronic Toxicity of 983 (1965). Effluents and Receiving Waters to Freshwater 4Abram, F. S. H., V. M. Brown, H. A. Painter, Organisms, EPA 600/4-85/014 (1985). and A. H. Turner, Proceedings of lV Yugoslav 27Boyer, S. L., K. F. Guin, R. M. Kelly, M. L. Symposium on Surface Active Substances, Mausner, H. F. Robinson, T. M. Schmitt, C. R. Section D, Dubrovnik, October 1977. Stohl, and E. A. Setzkorn, Environ. Sci. Tech- 5Sykes, R. M., A. J. Rubin, S. A. Rath, and M. no/. 11, 1167 (1977). C. Chang, J. Water Poll. Control Fed. 51, 71 28 Swisher, R. D., Surfactant Biodegradation, Sur- (1979). factant Science Series, Vol. 18, page 549, Mar- ) 6Kravetz, L., J. Am. Oil Chem. SOC. 58, 58A cel Dekker, Inc., New York (1987). (1981).

6 29Gerike, P., and W. K. Fischer, Ecofoxicol. Env. Safety 5, 45 (1981 ). 3 30Pitter, P., Sb VSChT 8(2), 13 (1964). 3’Ruiz Cruz, J. and M. C. Dobarganes Garcia, Grasas Aceites 28, 325 (1977). 32Zahn, R. and H. Wellens, Z. Wass.-Ab- W~SS-~O/SC~73, 1 (1980). 33Patterson, S. J., C. C. Scott, and K. B. E. Tuck- er, J. Am. Oil Chem. SOC. 47, 37 (1970). 34Sch0berl, P., and K. J. Bock, Tenside 77, 262 (1980). 35Yoshimura, K., J. Am. Oil Chem. SOC.63, 1590 (1986). 36Maki, A. W. and W. E. Bishop, Arch. Environm. Contam. Toxicol. 8, 599 (1979). 37Giger, W., P. H. Brunner, M. Ahel, J. McEvoy, A. Marcomini, and C. Schaffner, Gas, Wasser, Abwasser 67, 111 (1987).

7 Table l/Surfactants tested

Alhyl carbon no. Intemal DistriBution methyl groups/ Surfactant Acronym “le Averacre hvdrophobe

Linear C 12- 15 AE - 7 EOa C12-15 AE-7(L) 12-15 13.5 0.1

Linear C 12- 15 AE - 9 EOa C12-15AE-9(L) 12-15 13.5 0.1

Linear C 14, 15 AE - 7 EOa C14, 15 AE-7(L) 14, 15 14.5 0.1 Branched C12AE- 7 EOb ClBAE-7(B) 10-14 11.9 2.9

Branched C 13 AE - 7 EOC C 13 AE -7(B) 11 -15 13.4 4.0

Branched NPE-9 EOd NPE-9(B) 9 9 1.7

Linear C 14, 15 Alcohol Sulfatee C 14, 15 AS(L) 14, 15 14.5 0.1 Branched C13 Alcohol Sulfate’ C13AS(B) 11 -15 13.4 4.0

aNEOROL@25 and NEODOL 45 ethoxylattes (Shell Ckmhl Co.). bMade by lab-scale ethoxylation of Emal 12 alcohol (-on Chemical Co.). Made by lab -scale ethoxylation of Emal 13 alcohol (&on Chemical Co.). digepa/ co-630 (GAF cop.). eMade by lab-scale sulfation of NEODOL 45 alcohol (Shell Chemical Co.). Made by lab-scale sulfation of mal 13 alcohol (Exxon Chemical Co.).

Table 2/Effect of hydrophobe on ultimate biodegradation of nonionic surfactants via COS evolution test

% Biodegradation at Initial Concentration Surfactant 10 mg/l 20 mg/l 50 mg/l C13 A€-7(B) 48 37 50

NPE - 9(B) 14 28 34

c12 - 15 AE - 9(L) 64 67 79

Na Benzoate 88 85 94

a Table 3Biotreater operating conditions /3 Parameter Condition Synthetic Waste Modif ied Huss m an n (OECD/EEC) Sewage

Activated Sludge Houston Domestic Waste Treatment Plant

Sludge Residence Time 45-60 Days Aerator MLSS 3500 - 4500 mg/l PH 7 - 7.5 Dissolved Oxygen 2-5 mg/l

'3 Table 4/Acute and chronic aquatic toxicity of neat surfactants

Acute (m.q/o Chronic (mg/l) Growth 90-hr LC50 48-hr LC50 Fathead Daphnia Fathead Daphnia Minnow Magna Surfactant Minnow Magna NOEC---- LOEC NOEC LOEC c 12 -15 AE -9(L) 1.6 1.3 0.4 1.0 1.0 > 1.0

C13 AE-7(8) 6.1 11.6 1.0 2.0 4.0 > 4.0

NPE - 9(B) 4.6 14.0 1.0 2.0 10.0 >10.0

9 Figure l/Structural features of nonionic classes

Linear Primary Alcohol Ethoxylates RO(CH2CH2O)”H R = CH3(CH2); Branched Primary Alcohol Ethoxvlates RO(CH2CH2O)nH CH3I CH*I

CH3I CH3 CH2

R = CH3-F-CH2-k-CH2-{-CH2-I H H CH3

Figure 2/Bench-scale continuous activated sludge biotreater

Effluent

Sludge Recycle Pump Surfactant Vessel FeedI Vessel

10 Figure 3/Effect of hydrophobe on biodegradation of nonionic surfactants via BOD test

100 I

0 5 10 15 20 25 30 Days

3 Figure 4/Effect of hydrophobe chain length on biodegradation of nonionic surfactants via BOD test

loo , 1

0 5 10 15 20 25 30 Days

11 Figure 5/Effect of hydrophobe on biodegradation of alcohol sulfates via BOD test

0 5 10 15 20 25 30 Days

Figure G/Effect of hydrophobe on ultimate biodegradation of nonionic surfactants via COP evolution test

80 1

0 0 5 10 15 20 25 30 Days

12 Figure 7/Effluent CTAS at 25 OC biotreatment '7 Influent Surfactant Concentration, mg/l 5 10 25 50

- Control 2.0 1 - 1.5 E 1 d 1.0

0.5

0 40 80 120 160 200 240 Days

3 Figure 8/Effluent CTAS at 25 OC biotreatment

Influent Surfactant Concentration, mg/l 5 10 25 50 2.5 - Control 2.0

0.5

0 40 80 120 160 200 240 Days

13 Figure S/Effluent CTAS at 25 OC biotreatment

Influent Surfactant Concentration, mg/l 25 50 - Control 2.0

40 80 120 160 200 240 Days

Figure lO/Effluent foaming at 25 OC biotreatment

Influent Surfactant Concentration, mg/l 5 10 25 50

40 80 120 160 200 240 Days

14 Figure 11IEffluent foaming at 25 OC biotreatment

Influent Surfactant Concentration, mg/l 5 10 25 50

40 80 120 160 200 240 Days

Figure 12IEffluent foaming at 25 OC biotreatment

Influent Surfactant Concentration, mgll 5 10 25 50

I - Control

40 80 120 160 200 240 Days

15 Figure 13/Effluent CTAS at low temperature biotreatment

10 - Control '1 25OC 15 'C F6 1

0 0 7 14 21 28 35 42 49 56 63 70 77 84 91 98 Run Day

Figure 14/Effluent CTAS at low temperature biotreatment

10 - Control 8- 15 OC

0 7 14 21 28 35 42 49 56 63 70 77 84 91 98 Run Day

16 0 9

Figure 1WEffluent CTAS at low temperature biotreatment 3 10 - Control

0 7 14 21 28 35 42 49 56 63 70 77 84 91 98 Run Day

'd Figure 16/Acute toxicity of biotreated surfactant effluents, biotreated at 25 OC

120 (Influent Surfactant Conc: 50 mg/l)

2o0 Control1 Ci*-iSAE-Q(L) NPE-9(6) C13AE-7(8) Surfactants

17 Figure 17Ehronic aquatic toxicity of biotreated surfactant effluents, biotreated at 25 OC

120 (Influent Surfactant Conc: 50 mg/l) I

20 -

0' I I I Control C12-15AE -9b) NPE - 9(B) CiaAE-7(B) Surfactants

18 3 Shell Chemical Company Sales Offices Warranty

Atlanta 320 Interstate North Parkway All products purchased from or supplied by Shell are (404) 955-4600 Atlanta, Georgia 30339 subject to terms and conditions set out in the contract, order acknowledgement and/or bill of lading. Shell war- 4225 Naperville Road, Suite 375 Chicago rants only that its product will meet those specifications (708) 955-6500 Lisle, Illinois 60532 designated as such herein or in other publications. All Houston 3200 Southwest Freeway, Suite 1230 other information supplied by Shell is considered accu- (713) 241-81 01 Houston, Texas 77027 rate but is furnished upon the express condition that the N. Brookhurst Street customer shall make its own assessment to determine Los Angeles 511 the product’s suitability for a particular purpose. Shell (714) 991-9200 Anaheim, California 92801 makes no other warranty, either express or implied, Short Hills 150 JFK Parkway including those regarding such other information, (201) 912-3600 Short Hills, New Jersey 07078 the data upon which the same is based, or the results to be obtained from the use thereof; that any For sales outside the US. contact: Pecten Chemicals, Inc. P.O. Box 4407 product shall be merchantable or fit for any particu- (713) 241-61 61 Houston, Texas 77210 lar purpose; or that the use of such other information or product will not infringe any patent.

Printed in U SA September 1991 2M