EPA-600/2-76-231 September 1976 Environmental Protection Technology Series TREATING WOOD PRESERVING PLANT WASTEWATER BY CHEMICAL AND BIOLOGICAL METHODS I 55 \ Industrial Environmental Research Laboratory Office of Research and Development U.S. Environmental Protection Agency Cincinnati, Ohio 45268 ------- RESEARCH REPORTING SERIES Research reports of the Office of Research and Development, U.S. Environmental Protection Agency, have been grouped into five series. These five broad categories were established to facilitate further development and application of environmental technology. Elimination of traditional grouping was consciously planned to foster technology transfer and a maximum interface in related fields. The five series are: 1. Environmental Health Effects Research 2. Environmental Protection Technology 3, Ecological Research 4. Environmental Monitoring 5. Socioeconomic Environmental Studies This report has been assigned to the ENVIRONMENTAL PROTECTION TECHNOLOGY series. This series describes research performed to develop and demonstrate instrumentation, equipment, and methodology to repair or prevent environmental degradation from point and non-point sources of pollution. This work provides the new or improved technology required for the control and treatment of pollution sources to meet environmental quality standards. This document is available to the public through the National Technical Informa- tion Service, Springfield, Virginia 22161. ------- EPA-600/2-76-231 September 1976 TREATING WOOD PRESERVING PLANT WASTEWATER BY CHEMICAL AND BIOLOGICAL METHODS by John T. White T. A. Bursztynsky John D. Crane Richard H. Jones Environmental Science and Engineering, Inc. Gainesville, FL 32604 Grant No. 12100 HIG Project Officer Victor Dal Ions Industrial Environmental Research Laboratory Con/all is, Oregon 97330 INDUSTRIAL ENVIRONMENTAL RESEARCH LABORATORY OFFICE OF RESEARCH AND DEVELOPMENT U.S. ENVIRONMENTAL PROTECTION AGENCY CINCINNATI, OHIO 45268 ------- DISCLAIMER This report has been reviewed by the Industrial Environmental Research Laboratory, U.S. Environmental Protection Agency, and approved for publication. Approval does not signify that the contents necessarily reflect the views and policies of the Environmental Protection Agency, nor does mention of trade names or co-mercial products constitute endorsement or recommendation for use. ii ------- FOREWDRD When energy and material resources are extracted, processed, converted, and used, the related pollutional impacts on our environment and even on our health often require that new and increasingly more efficient pollution control methods be used. The Industrial Research Laboratory - Cincinnati (IEKL-CI) assists in developing and demonstrating new and improved methodo-; logics that will meet these needs both efficiently and economically. "Treating Wood Preserving Plant Wastewater By Chemical And Biological Methods" was a part of the Industrial Pollution Control Division's program to develop and demonstrate new technology for the treatment of industrial wastes. This project demonstrated the biological treatment of wood pre- serving wastes containing pentachloropenols and creosote using complete mixed activated sludge. The study showed that the system could obtain BOD removals of 90 percent and phenol removals of 99 percent. The information will be of value to consultants and industry concerned with installation of treatment facilities to meet more rigid effluent standards. For further information, please contact the Food and Wood Products Branch of the In- dustrial Environmental Research Laboratory, Cincinnati. David G. Stephan Director Industrial Environmental Research Laboratory Cincinnati in ------- ABSTRACT A completely mixed activated sludge system was designed for a wood preserving plant with an average daily wastewater flow of 27,000 /day (7,150 gal/day), a BOD concentration of 1,100 mg/], and a phenol concen- tration of 120 mg/1. Included in the design were capabilities for pre- chlorination and post-chlorination. The activated sludge system lone was capable of removing 90 percent BOD, 75 percent COD, 99 percent phenol, and 76 percent pentachlorophenol. Shock loadings had minor effects on BOD and COD removals but reduced the phenol removal and completely prevented penta- chlorophenol removal. Post-chlorination dosages of over 50 mg/1 resulted in reductions of 50 and 52 percent for phenol and pentachlorophenol, respectively, during the study. The Safranin method was used for measuring penta. Later fol- low-up work by Kbppers using vapor phase chromatography with electron de- tection showed penta reductions of 5 mg/1 to 0.1 mg/1. There was no reduc- tion of COD. A pre-chlorination study showed no removal of phenol, penta- chlorophenol, or COD at the level studies in the full scale plant. Labora- tory pre-chlorination studies showed removal of phenol and pentachloro- phenol at chlorine dosages in excess of 250 mg/1. This report was submitted in fulfillment of EPA Grant No. 12100 HIG by Environmental Science and Engineering, Inc., Gainesville, Florida, for Kbppers Company, Inc., Pittsburgh, Pennsylvania, under partial sponsor- ship of the Water Quality Office, Environmental Protection Agency. The study was completed as of July 1974. IV ------- TABLE OF CONTENTS SECTION PAGE NO. ABSTRACT iv ACKNOWLEDGEMENTS x I CONCLUSIONS 1 II RECOMMENDATIONS 2 III INTRODUCTION 3 IV LITERATURE REVIEW AND PRELIMINARY STUDIES 8 V MATERIALS AND METHODS 40 VI RESULTS AND DISCUSSION 54 VII REFERENCES 77 VIII GLOSSARY 83 IX APPENDIX 85 ------- TABLES No. Page 1 Efficiencies of Oil Separation Processes 8 2 Effect of Lime Flocculation on COD and Phenol Content of Treating-Plant Effluent 11 3 Threshold Toxic Levels for Continuous Dosages in Aerobic Treatment Processes 11 4 Chlorination of Phenolic Materials 14 5 Effect of Chlorination of Pentachlorophenol Waste on COD 21 6 Substrate Removal at Steady-State Conditions in Activated Sludge Units Containing Creosote Wastewater 24 7 Reduction in Pentachlorophenol and COD in Wastewater Treated in Activated Sludge Units 26 8 BOD, COD, and Phenol Loading and Removal Rates for Pilot Trickling Filter Processing a Creosote Wastewater 29 9 Relationship between BOD Loading and Treatability for Pilot Trickling Filter Processing a Creosote Wastewater 30 10 Sizing of Trickling Filter for a Wood Preserving Plant 31 11 Average Monthly Phenol and BOD Concentrations in Effluent from Oxidation Pond 34 12 Results of Laboratory Tests of Soil Irrigation Method of Wastewater Treatment 36 13 Reduction of COD and Phenol Content in Wastewater Treated by Soil Irrigation 37 14 Analytical Data from Pre-Design Study 42 15 Revised Operating Schedule 51 ------- TABLES CONTINUED No. Page 16 Schedule of Analyses 52 17 Startup and Stabilization Data 55 18 Effects of Shock Loading 57 19 Results of Loading Rate Variation 59 20 Laboratory Post-Chlorination Studies 64 21 Effects of Full Scale Post-Chlorination 67 A Daily Log Summary 90 B Post-Chlorination 97 vii ------- FIGURES No. Page 1 Original Wastewater Treatment Flow Diagram, Koppers Company, Carbondale " 6 2 Effect of Detention Time on Oil Removal by Gravity Separation 9 3 Reaction Scheme for the Chlorination of Phenol 13 4 Observed Rates of Chlorination of Phenol and Chlorophenols 16 5 Chlorination of Phenol and the Chlorophenols Formed at pH7 17 6 Chlorination of Phenol and the Chlorophenols Formed at pH 8 18 7 Chlorination of Phenol and the Chlorophenols Formed at pH 9 19 8 Determination of Reaction Rate Constant for a Creosote Wastewater 23 9 COD Removal from a Creosote Wastewater by Aerated Lagoon without Sludge Return 25 10 Phenol Content in Oxidation Pond Effluent before and after Installation in June 1966 of Aerator 33 11 Relationship between Weight of Activated Carbon Added and Removal of COD and Phenols from a Creosote Wastewater 39 12 Flowrate Variation with Time 41 13 Percent Dilution vs. BOD 45 14 Schematic of "Package" Treatment System %Q 15 Influent and Effluent Phenol Concentration 63 vm ------- FIGURES CONTINUED No. Page 16 Chlorine Residuals with Time 65 17 Effects of Chlorine on Pentachlorophenol Concentrations as Measured by Safranin Method 66 18 (a,b) Chlorine Persistence 69,70 19 Effect of Chiorination on Phenolic Concentration of Raw Wastewater with Activated Carbon 71 20 Effect of Chiorination on Penta Concentration of Raw Wastewater with Activated Carbon 72 21 COD Removal in the Activated Sludge Process 75 ix ------- ACKNOWLEDGEMENTS ENVIRONMENTAL SCIENCE AND ENGINEERING, 1C. Environmental Science and Engineering, Inc., (ESE) of Gainesville, Florida, as a consultant to Koppers Company/ provided overall supervision of the project. The concepts of the program and the treatment facilities were developed by Dr. Richard H. Jones, P.E. The Project Manager for the first year of the project, Mr. T. A. Bursztynsky, P.E., was respon- sible for planning the technical program. Mr. John T. White supervised much of the program and contributed substantially to preparation of this report. Mr. John D. Crane, P.E./ supervised preparation of the final report and coordinated reviews by EPA and Koppers personnel. Dr. W. S. Thompson of the Forest Products Research Laboratory, Mississippi State University, provided valuable consulting services to ESE. KOPPERS COMPANY The program was partially funded by Koppers Company, Pittsburg, Pennsylvania. Mr. Marvin D. Miller, P.E., provided engineering coordiviation for the project. Mr. Roy Burke served as chief operator for the treatment plant. Considerable input to the project was also provided by Mr. G. R. Tallon, Mr. C. W. Fisher, and Mr. Paul A. Goydan and other members of the Environmental Engineering Section of the Forest Products Division. Mr. X. P. Laskaris served as Grant Director. ENVIRDNMENTAL PROTECTION AGENCY The Project Officer was Mr. Victor Dallons. Technical review and assistance were provided by Mr. Ralph Scott and Mr. James H. Phillips. The program was partially funded by EPA" under Grant No. 12100 HIG. ------- SECTION I CONCLUSIONS It was demonstrated that wastewater from a wood preserving process utilizing creosote and pentachlorophenol (penta) as preservatives can be effectively treated by a biological system. The process employed was the complete mix activated sludge process. The process obtained a BOD reduction of 90 percent and a phenol removal efficiency of 99 percent. Pre-chlorination was effective in reducing both penta and phenol in laboratory tests. However, in the full scale plant, a chlorine/ penta ratio of 300:1 was required to achieve an 80 percent reduction in penta and the resulting excessive chlorine residuals caused operation- al problems in the biological treatment system. Post-chlorination provided considerable color removal and reduced the penta concentration from about 5 mg/1 to less than 0.10 mg/1. It also accomplished slight reductions in phenol concentrations. There was no apparent reduction of COD. Shock loading tests showed a noticeable decrease in treatment efficiency. A doubling of the hydraulic loading rate resulted in a decrease in phenol removal from 99 to 89 percent, in COD from 80 to 72 percent, and penta from 79 to 0 percent. There was little apparent effect on BOD removal efficiency. The usefulness of BOD as a pollutant parameter was limited as the characteristics of the wastewater apparently inhibited the test, e.g., an increase in dilution in the BOD test from 99.8 to 99.9 percent resulted in an increase in BOD from 1000 to 2000 mg/1. The Safranin method for measuring pentachlorophenol was of questionable reliability in testing the biological treatment effluent; an increase in penta was indicated across the activated sludge unit. It should be noted that near the end of the study, vapor phase chromatography using electron capture detection was found to be a relative method for penta detection at low levels and indicated that the Safranin analyses were generally high. ------- SECTION II RECOMMENDATIONS The activated sludge process provides a potential means as a viable treatment alternative for the treatment of wood preserving wastewater where limited land is available for spray irrigation and lagooning. For plants which have limited land available for spray irrigation or lagooning, the activated sludge process could represent the most cost-effective treatment alternative. The activated sludge process should be recommended to the wood preserving industry as a potential means of meeting increasingly stringent effluent limitation standards. A properly designed and operated preservative recovery system is recommended before activated sludge treatment. Also, a surge basin is imperative for successful operation of the activated sludge system. The key design parameters for the complete mix system are as follows: 1. Maximum BOD Loading =0.2 kg/day/kg MLSS 2. Maximum COD Loading =0.5 kg/day/kg MLSS 3. Maximum Penta Loading = 6.5 gm/day cu m U. Minimum hydraulic detention time = Uo hours ------- SECTION III INTRODUCTION The Koppers Company, Inc., wood preserving plant at Carbondale, Illinois, was selected by the Environmental Protection Agency in 1971 as a site for a demonstration project to determine the design and operating parameters for chemical and biological treatment of both creosote and pentachlorophenol (penta) wastewaters generated by a wood preserving operation. The wastewater from the Carbondale plant is representative of wood preserving wastewater in that it has a high Biochemical Oxygen Demand (BOD) and contains wood preserving compounds and extractives. The successful development and operation of treatment facilities at the Carbondale plant alleviates a specific pollution problem at that plant and, more importantly, provides design parameters for similar wood preserving plants. BACKGROUND A number of methods have been developed to increase the service- ability of wood*under conditions that promote decay, weathering, insect destruction, or exposure to fire. Treated or preserved wood is used in almost every facet of the construction industry. Included among the various wood materials that are treated with preservatives or fire retardants are general lumber and timber, bridge ties, foundation piles, posts, crossties, utility poles, and marine construction wood. Preservative and Fire Retardant Chemicals The various preservatives in common use throughout the industry include creosote, creosote-coal tar, creosote-petroleum and pentachloro- phenol solutions, as well as water-borne preservatives and fire retardants, Creosote, creosote-coal tar, and pentachlorophenol-oil preservatives are used at the Koppers Company facility at Carbondale; however, creosote is the principal preservative used. Creosote, a distillate of tar produced by the carbonization of bituminous coal, is used as a wood preservative both because it protects wood against wood destroying organisms and has a high degree of perse- verance. The main constituents of creosote are tar acids. The mixture of creosote with coal tar is primarily for railroad ties and marine installations that require a preservative with water- repelling properties. Common ratios of creosote to coal tar are 80:20, 70:30, 60:40, and 50:50. Pentachlorophenol, frequently called "Penta", has a relatively low solubility in water of about 15 mg/1 at normal water temperatures. It is normally applied with a carrier petroleum oil. ------- Water-borne preservatives are basically heavy metal compounds of copper, chromate, arsenite or arsenate, and zinc. One of the chief advantages of this treatment is that the wood is paintable. Water- borne preservatives are not used at the Carbondale plant. Fire retardant formulations are designed to slow the spread of fire in treated wood. There are generally four formulations used in the industry, with water used as the preservative carrier. Prior to the commencement of the investigation, the Carbondale Facility used a formulation containing a borate. Description of the Wood Preserving Process The wood preserving process consists of two basic steps: (1) preconditioning the wood to reduce its natural moisture content and (2) impregnating it with the desired preservatives. The moisture reduction step may consist of (1) seasoning or drying the wood in large, open yards, (2) kiln drying, or (3) steaming the wood for several hours at elevated pressures to raise the temperature of the moisture in the wood cells, and subsequently applying a vacuum to reduce the boiling point of the water and evaporate it. Nearly 70 percent of the wood produced at the Carbondale plant consists of crossties and switch ties which are air seasoned in a storage yard. Approximately 10 percent of the production at the Carbondale plant is pretreated by steaming. Kiln drying requires from four to ten days for pretreatment as compared to approximately 12 hours for steaming. Pretreatment of wood by steaming may be done in one of three ways: (1) open steaming, (2) closed steaming, and (3) semi-closed steaming. Open steaming consists of placing the wood in retorts and applying steam under pressure to the retorts for a period of several hours after which vacuum is applied to remove wood water to the effluent system. As the applied steam condenses on the wood and on the sides of the retort, it drains down and is eventually removed as wastewater. This condensate tends to collect preservatives deposited in the retort from previous processing. In the closed teaming cycle, water is introduced into the retort and the wood is heated by steam generated by heating coils in the bottom of the retort. At the end of the cycle , the water is with- drawn to a storage tank from which it may be reused. Eventually a blowdown of the steaming water is necessary because of the buildup of wood extractives. At Carbondale this blowdown goes to the treatment system. The Carbondale plant uses four retorts for the application of the semi-closed steaming cycle for wood pretreatment. In this process, steam is added to the retort under vacuum to reduce the condensation temperature and lower the boiling temperature of water entrained in the wood. As steam condenses in the retort, the liquid level is allowed to build up until it covers the heating coils in the bottom of the ------- retort. Live steam is then turned off and heat is applied to the coil. At the end of steaming all water is discharged to waste and a vacuum continues to be drawn to remove additional moisture from the wood. After the initial pretreatment step, there are several possible ways to impregnate wood with preservatives. For all creosote and pentachlorophenol treatments not requiring a heavy saturation of pre- servatives, the Carbondale plant uses the empty-cell Rueping process. The full-cell process is used for treatment applications requiring heavy saturations and for applications of fire retardant. The empty-cell Rueping process provides greater penetration of preservative for net amounts of preservative absorbed and allows a relatively high recovery of excess preservative. The full-cell process allows a higher saturation of preservative within the wood cells. Wastewater Sources from the Wood Preserving Process The basic wood preserving process generates wastewater .streams consisting of condensed water from steaming, barometric leg cooling water or surface condenser condensate, boiler blowdown, miscellaneous wash water, p/ipe and tank leakages, and door pit drips. In the semi-closed steaming process, by which condensate is allowed to accumulate in the retort until it covers the heating coils, the condensate is wasted after oil recovery. The wasted condensates contain oil, phenolic compounds, and various wood extractives. When barometric legs or wet-type vacuum pumps are used to produce vacuum, a water contaminated with the preservative used is generated. The Carbondale facility employs a vacuum pump preceded by a surface condenser. Volatile gases are condensed on the surface condenser and are discharged to waste. The pump is sealed and lubricated by water circulated through a small pond. Boiler blowdown is usually a stream of small volume, but one that can be contaminated with various chemicals such as chromates and phos- phates used for boiler water conditioning. Water used to clean equipment is normally contaminated with pre- servative chemicals, oil and grease, and possibly detergents. Existing Wastewater Treatment Facilities at Initiation of Project The wastewater treatment system in employment at the Carbondale plant at the time of project initiation is illustrated in Figure 1. Since specific preservatives are used in a retort, it is possible to segregate wastewaters for pretreatment. Wastewater from the penta- chlorophenol oil retorts is pumped to a decanter from which the floating oil fraction containing pentachlorophenol is recovered. The water fraction, after addition of a polymeric flocculant, is pumped ------- POND 4 POND 3 POND 2 POND I (RESERVE) SPRAY IRRIGATION FIELD CREOSOTE SETTLER x\ PENTA SEPAR PENTA-OIL TO WORK TANK ^ DRAINAGE TROUGH KTQR^/^ ~\ i S WORK AREA CONTRIBUTORY S DRAINAGE FIELD 3 COMMON SUMP POLYMERIC FLOCCULANT .ADDITION \ -- > WORK TAf ^ AND SKI ^- CREOSOTE Ml Ml TC \ /SUMP ... I 4 CREOSOTE 1 3 CREOSOTE | Z PENTA * 1 WS^ PENTA ^ Viy RETORT RETORT RETORT RETORT ^~&£ =^^- I 1 1 1 .-•-' «AO \ DIVIDING WALL PRIMARY PENTA-OIL DECANTER FIGURE 1. Original Wastewater Treatment Flow Diagram - Koppers Company, Carbondale ------- to a secondary recovery tank for further separation. The water from the second tank is transferred to a common sump. Wastewaters are collected and handled separately in a similar manner as the penta-oil wastewaters with recovered creosote returned to the system. The clarified water is discharged to the common wet well. The wastewater from the common sump is pumped to the set of four lagoons which provides equalization, evaporation, and biological oxidation. A spray irrigation field provides final treatment. PROJECT OBJECTIVES The project objectives were to determine the design and operating parameters of chemical and biological treatment of creosote and penta- chlorophenol-oil wastewaters from a wood preserving plant. The plan of operation consisted of design, construction, and operation of treat- ment facilities for the wastewaters generated by the Koppers Company wood preserving plant located at Carbondale, Illinois. The operation and sampling and testing program would be supervised by Environmental Science and Engineering, Inc., of Gainesville, Florida. -7- ------- SECTION IV LITERATURE REVIEW AND PRELIMINARY STUDIES In order to best meet the objectives of the project, an extensive review of the literature and other previous work related to the treatment of wood preserving wastes was conducted. PHYSICAL TREATMENT The first step in treating wastewater from a plant using creosote or creosote solutions is usually settling and skimming, not so much for treating wastewater, but to recover valuable preservatives. The most common type of separator in use by the industry is modeled after the separator developed by the American Petroleum Institute (1) which basically consists of a horizontal tank divided into three or more compartments. Heavy oils settle to the bottom of the tank and are removed by a pump to a dehydrator. Floating oils are removed by a skimmer. The amount of entrained oils removed by separation equipment depends in part on whether the oil is in a free or emulsified form. Data on the percent efficiencies of several separators are presented in Table 1 (2). The variability of oil removal as a function of detention time was shown by Wallace, e_t. al_. (3), as illustrated in Figure 2. TABLE 1. EFFICIENCIES OF OIL SEPARATION PROCESSES Source of Influent Percent Removal Free Oils Emulsified Oils API Separator Raw Waste 60 - 99 Not applicable Air Flotation without Chemicals Air Flotation with Chemicals Chemical Coagulation and Sedimentation API Effluent API Effluent API Effluent 70 75 60 - 95 - 95 - 95 10 50 50 - 40 - 90 - 90 The conventional oil-water separators discussed above remove only free oils. Emulsions may be broken by rotary vacuum filters or by centrifugation. Both of these methods have been tested at a few wood preserving plants, but chemical methods involving flocculation and sedimentation are the most widely used. -8- ------- 10 20 30 h- UJ o g 40 Q. 50 UJ ce -J 60 o 70 80 AVERAGE TEMPERATURE - 38° C INITIAL OIL CONCENTRATION- 45 PPM. * 4P.P.M. 0 40 80 120 160 200 SEPARATION TIME IN MINUTES FIGURE 2 Effect of Detention Time on Oil Removal by Gravity Separation -9- ------- CHEMICAL TREATMENT Chemical Precipitation The effluent from the settling and skimming tanks contains a considerable amount of emulsified oil and creosote. This emulsion represents a large portion of the BOD in the wastewater; wastewaters containing emulsified oils often have oil concentrations in excess of 1000 mg/1 after separation (4). Middlebrooks and Pearson (5) found that 79 percent of the BOD and 80 percent of the COD in this type of wastewater could be removed by chemical coagulation with the addition of approximately 2000 mg/1 of lime and alum. However, the volume of sludge produced was almost 40 percent. Frank and Eck (6) found similar results with sodium hydroxide and lime after polyelectrolytes alone failed to produce flocculation. Although the treatment efficiencies were high, the problem of sludge disposal would suggest that another type of treat- ment for breaking the emulsion might be more feasible. Jones and Frank (7) achieved COD and BOD reductions of 83 and 73 percent, respectively, in creosote wastewater using a single cationic polymer at a rate of 40 mg/1. Anionic polymers failed to break the oil emulsions. However, Simonsen (8) was successful in obtaining oil reductions in refinery wastewater of more than 95 percent by the use of both anionic and cationic polyelectrolytes in combination with bentonite clay. There was no difference between the two types of polymers in the results obtained. Thompson and Dust (9) found ferric chloride to be an effective flocculant for both creosote and pentachlorophenol wastewaters with very narrow pH limits. In the same study, from 0.75 to 2.0 gm/1 of lime appeared to be an optimum dosage for reduction of COD and phenol, as shown in Table 2. Lime was also employed by Middlebrooks (10) in dosages of 2 gm/1 to obtain reductions in COD of up to 70 percent in creosote wastewater. Similar results were obtained with alum. Both lime and alum were used by Gaspin (11) for treatment of creosote wastewater previously de- emulsified with sulfuric acid. Treatment of wastewater containing heavy metals has been success- fully practiced for many years in various industries. Chromium is found in wastes from metal plating and finishing operations. It is present in rinse waters and chromic acid baths and in spent baths from electroplating and anodizing processes. Wastewaters from similar processes also contain copper and zinc. Heavy metals contained in salt-type preservatives and fire retardants are toxic to microorganisms, even when the metals are in relatively low concentrations (12) (see Table 3). Other studies (13), using a combination of metals, showed that the aeration phase of bio- logical treatment can tolerate chromium, copper, nickel, and zinc, up -10- ------- TABLE 2. EFFECT OF LIME FLOCCULATION ON COD AND PHENOL CONTENT OF TREATING-PLANT EFFLUENT COD Lime (qm/1) 0.0 0.25 0.50 0.75 1.00 1.25 1.50 PH 5.3 6.8 7.9 9.7 10.5 11.4 11.8 Cone. (mg/1) 11,800 9,700 7,060 5,230 5,270 5,210 5,210 Percent Removal — 23 39 56 55 56 56 Phenol (mg/1) 83 81 72 78 80 84 83 TABLE 3. THRESHOLD TOXIC LEVELS FOR CONTINUOUS DOSAGES IN AEROBIC TREATMENT PROCESSES Metal Chromium (VI) Copper Nickel Zinc Wastewater Concentration (mg/1) 10 1 1-2.5 5-10 -11- ------- to a total heavy metal concentration of 10 mg/1, either alone or in combination, with about 5 percent reduction in overall plant efficiency. Various other studies (14, 15, 16), both in the laboratory and in the field, reached similar conclusions. Chemical analyses to determine heavy metal concentrations should be conducted on the wastewater from wood preserving plants using water-borne preservatives. If heavy metal removal is necessary, chemical treatment related to the specific ions present is applied. Usually precipitation of heavy metals from wastewater is accomplished with lime; however, hexavalent chromium must be reduced to a trivalent state by ferrous sulfate or sulfur dioxide prior to lime precipitation. The use of sulfur dioxide has been described in detail by Chamber!in and Day (17) and Fisher (68). A bibliography dealing with the removal of heavy metals was com- piled in 1949 by Dodge and Reamms (18) and it has been estimated by the American Wood Preserver's Association (19) that by 1959 some 500 addi- tional articles had been published on the subject. Detailed discussions of heavy metal removal have also been presented by Eckenfelder (20) and Bliss (21). Chemical Oxidation While some information is available on oxidation of phenols using peroxide, ozone, and other chemical oxidants (22, 23), the vast majority of literature is concerned with the oxidation of phenolics with chlorine, especially as related to the water supply area. It has long been common knowledge that chlorination of phenols may produce tastes and odors in water supplies. Early studies on chlorination of phenols centered on chlorine residuals and removal of tastes from water. Based on ratios of chlorine to phenol, Ingols and Ridenour (24) concluded that a quinone- like substance was the basic cause of "phenol" tastes. Their work postulated a succession of chlorination products which ultimately ended in dichlor-quinone. Further chlorination of dichlor-quinone was postu- lated to rupture the benzene ring and form maleic acid rather than completely eliminate any residual taste problems. Subsequent studies by Ettinger and Ruchhoft (25) substantiated early work showing increasing taste intensity with increasing chlorina- tion of phenols and then decreasing taste until no taste was noticeable and a chlorine residual began to develop. Comparative information was provided on the chlorination of various phenolic compounds and quantities of chlorine needed to eliminate detectable taste products. Table 4 indicates that a chlorine to cresol ratio of 5:1 would be adequate to completely form chlorination end products. Pentachlorophenol could be oxidized by chlorine at a 1:1 ratio. The first fact substantiated from early work of researchers was the progression of chlorination products as illustrated in Figure 3. In more recent studies, R. G. Burttschell and co-researchers (26) at the Robert A. Taft Sanitary Engineering Center uses paper chromatography and infrared and ultraviolet spectrophotometry to determine the actual products -12- ------- OH Oxidation FIGURE 3. Reaction Scheme for the Chlorination of Phenol -13- ------- involved in the chlorination of phenols. According to these studies, the chlorination of phenol proceeds by stepwise substitution of the 2, 4, and 6 positions of the aromatic ring. Initially, phenol is chlorinated to form either 2- or 4- chlorophenol. Then 2- chloro- phenol is chlorinated to form either 2, 4- dichlorophenol or 2, 6- dichlorophenol while 4- chlorophenol forms 2, 4- dichlorophenol. Both 2, 4- and 2, 6- dichlorophenol are chlorinated to form 2, 4, 6- trichlorophenol. The 2, 4, 6- trichlorophenol reacts with aqueous chlorine to form a mixture of non-phenolic oxidation products. TABLE 4. CHLORINATION OF PHENOLIC MATERIALS Material @ 1 mg/1 Phenol 0-Cresol M-Cresol P-Cresol 1 -Naphthol 2-Chlorophenol 4-Chlorophenol 2-, 4-Di chlorophenol 2-, 4-, 6-Trichlorophenol 2-, 4-, 5-Trichlorophenol 2-, 3-, 4-, 6-Tetrachlorophenol Pentachlorophenol Chlorine Required to Chlorine Added Eliminate Taste to Produce Free (mg/1) Residual (mg/1) 4 5 5 3 4 3 3 2 Could Not be Tasted Could Not 'be Tasted Could Not be Tasted Could Not be Tasted 7 5 5 4 5 5 6 6 3 2 1.5 1.0 The principal taste causing compounds were found to be 2-chlorophenol, 2, 4- dichlorophenol, and 2, 6- dichlorophenol. The development of the chlorophenolic taste did not occur at pH values less than 7.0 and the presence of ammonia significantly retarded the rate of reaction between phenol and chlorine. Of prime importance was the discovery that at a chlorine to phenol ratio of 10:1, the aromatic benzene ring is destroyed. An optimum pH of 8 was found to be helpful for rapid chlorination of -14- ------- phenolic compounds using hypochlorous acid; however, reaction rates would be different under acidic conditions using chlorine gas since molecular chlorine is the most probable reacting agent. Therefore no information was provided on the mechanism of chlorination or reaction rates using chlorine gas at low pH values. Later studies by Lee (27) provided information on the kinetics of reaction of phenolic compounds and chlorine. According to Lee, the chlorination of phenol and each of the chlorophenols conforms to a second-order rate expression in which the rate of change of chlorine or phenolic compounds is proportional to the product of the formal concen- trations of aqueous chlorine and phenolic compounds, or: -dF Cl = K F F ~dT~ ob Cl PhOH Rate constants were determined for each phenol compound at various pH levels and are plotted in Figure 4. Obviously, the rates of reaction of aqueous chlorine with phenol vary with pH with the maximum rate of reaction occurring .near neutrality for most species. It should be noted that the more acidic the phenolic compound the lower the pH of maximum reaction rate, and, as stated by Lee, those substitute groups of phenol which tend to make the substituted phenol more acidic also tend to decrease the rate of reaction of aqueous chlorine with this compound. Thus, it can be expected that the maximum reaction rate of chlorine with pentachlorophenol will occur at a pH somewhat less than 7, and that this reaction will be slower than the reaction of chlorine with less highly substituted phenols. Further, it is stated that in reacting with aqueous chlorine, phenol and the chlorophenols tend to undergo oxidative rupture of the benzene ring rather than substitution and that this tendency to rupture increases with more .highly chlorinated phenolic reactants. Figures 5, 6, and 7 show the reaction of aqueous chlorine with phenol and the chlorophenols with time. The initial chlorine dosage, using a stock chlorine solution prepared from gaseous chlorine, was 1.0 mg/1, the initial phenol concentration 50 mg/1, and the temperature 25° C. Figures 5, 6, and 7 represent the reactions at pH levels of 7, 8, and 9*, respectively. A minimum reaction time of two hours was required before a significant decrease in total molar concentration of phenolic compounds occurred. It should be remembered that these data represent the results of reactions in distilled water. The presence of ammonia, for instance, interferes significantly with the reaction of phenol with chlorine. Weil and Morris (28) indicate that for equal initial molar concentra- tions of ammonia and phenol at a pH of 8 and a temperature of 25° C, ammonia chlorinates to form NH2CL about a thousand times faster than phenol chlorinates to form monochlorophenol. Therefore, the usefulness of the work of Lee is only qualitatively applicable to a discussion of chlorination of a heterogeneous wastewater. 15 ------- 8000 6000 4000 - 2000 - ^ 1000 7E 800 £ 600 £ 400 . -Q O O '•M fC 200 - o 100 o 80 o 60 «/l 40 - 20 - 10 8 6 4 01 to «§ 2 . Phenol 2-Chlorophenol 4-Chlorophenol 2,4,6 Tricnloro phenol 2,6-Dichlorophenol 2,4-Dichlorophenol FIGURE 4. 45 6 7 8 9 10 11 12 13 PH Observed Rates of Chiorination of Phenol and Chlorophenols 16 ------- 20-, 18 - 16 _ Initial Chlorine 10 ppm Phenol 50 ppb Temperature 25° C. pH 7.0 Phenol V ^2-Chlorophenol 4-Chlorophenol \ 2,4-Dichlorophenol 1 2 TIME hrs FIGURE 5. Chlorination of Phenol and the Chlorophenols Fonned at pH 7, 17 ------- Initial Chlorine 10 ppm 11 Phenol 50 ppb Temperature 25° C. pH 8.0 \ /2-Chlorophenol 2,4-Dichlorophenol 2,6-Dichloro- phenol i 0.8 1.2 1.6 2.0 2.4 2.8 TIME hrs FIGURE 6. Chlorination of Phenol and the Chlorophenols formed at pH8. 18 ------- Phenol oo o _x 12 _ 01 § •I- 2 01 0 Initial Chlorine 10 ppm Phenol 50 ppb Temperature 25° C. pH 9.0 2,4-Dichlorophenol \2,5-Dichlorophenol FIGURE 7 T-~T — i — r 3456 TIME hrs. Chlorination of Phenol and the Chlorophenols Formed at pH 9 19 ------- Other researchers have also mentioned the oxidation of phenol bearing waters using either chlorine gas or chlorine dioxide (29, 30, 31). Glabisz (31) reported that chlorine dioxide would successfully convert phenolic wastes from coke works to quinones, organic acids, and carbon dioxide. Specific data on test conditions were not available for presentation. Successful oxidation of phenolics by chlorine was reported by the American Petroleum Institute (32). Apparently, low dosages of chlorine produce chlorophenolics which produce taste and odor problems. When a large excess of chlorine is supplied (5 grams/liter per 100 mg/1 phenol), the benzene ring is broken and a harmless non-phenolic compound is created. The theoretical ratio of chlorine to phenol for complete destruction is 6:1; however, other organic compounds present in the wastewater necessitate as much as 50 parts chlorine to 1 part of phenol. Again, the presence of ammonia was noted to retard the reaction of chlorine and phenols. The ratio of chlorine to ammonia to oxidize the ammonia is 10:1. Reaction times for chlorination were reported in terms of one to several hours. In conformity to the observed chlorination rates shown in Figure 5, at a pH less than 7 a predominance of chlorophenolics was noticed, while at higher pH levels (above 7) phenols were oxidized more rapidly and completely. In a study by H. R. Eisenhauer (22), chlorination was applied to an artificial 80 mg/1 concentration phenol solution and a refinery effluent of 78 mg/1 phenol and 627 mg/1 COD. Chlorine was added as sodium hypochlorite at a pH of 4 and a temperature of 50° C. Creation of chlorophenols and their destruction was directly related to increasing chlorine dosages. There was no measurable phenol after the addition of 200 mg/1 chlorine to the artificial solution, and the end products stabilized at dosages over 1000 mg/1 of chlorine. In the refinery effluent, 1000 mg/1 of chlorine were needed to remove all traces of phenol and the final chlorination product was achieved with less than 5000 mg/1 of chlorine. A pH in the range of 4 to 10 was not found to be an influencing factor. Work performed by Dust (33) substantiates the value of chlorination for pentachlorophenol removal. Table 5 presents data on the removal of pentachlorophenol from an actual wood preserving wastewater. Increasing dosages of chlorine as calcium hypochlorite were added at pH levels of 4.5, 7.0, and 9.5. Similarly, gaseous chlorine was added at pH levels of 4.5, 7.0, and 9.5 and at dosages from 0.0 to 5.0 grams/liter. The hypochlorite and gaseous chlorine were added to samples flocculated with lime at 18 mg/1 and 20 mg/1 of cationic polyelectrolyte and to samples not pretreated. Flocculation removed much of the chlorine demanding substances from the wastewater and the chlorine required for pentachlorophenol removed appeared to decrease with increasing pH. The reaction of gaseous chlorine with pentachlorophenol appeared to be less vigorous than when hypochlorite was used, especially at low concen- trations (2.0 to 4.0 rng/1) of pentachlorophenol. 20 ------- TABLE 5. EFFECT OF CHLORINATION OF PENTACHLOROPHENOL WASTE ON COD Test Conditions Calcium Hypochlorite pH » 4.5 Calcium Hypochlorite pH = 7. a Chlorine Gas pH = 4.5 Chlorine Gas pH - 7.0 Available Chlorine (g/liter) 0.0 0.5 1.0 1.5 2.0 3.0 4.0 5.0 0.0 0.5 1.0 1.5 2.0 3.0 4.0 5.0 0.0 Of .5 1.0 1.5 2.0 3.0 4.0 5.0 10.0 0.0 Of* .5 1.0 1.5 2.0 3.0 4.0 5.0 10.0 COD (mg/ liter) 24,200 10,650 10,600 10,300 23,800- 10,300 10,200 10,050 20,400 10,250 10,600 10,200 23,600 9^60 10,700 11,250 21 ------- BIOLOGICAL TREATMENT Activated Sludge Cooke and Graham (34) performed laboratory scale studies on the biological degradation of phenolic wastes by the complete mixed acti- vated sludge system. While many of the basic parameters needed for design such as MLSS were not presented, the final results were conclu- sive, The feed liquors contained phenols, thiocyanates, ammonia, and organic acids. Aeration varied from 8 to 50 hours. Influent concentration and percentage removal of phenol averaged 281 mg/1 and 78 percent, respectively at a volumetric loading of 144 to 1609 kg/100 m3/day (9 to 100 lb/1000 ft3/day). Badger and Jackman (35), studying bacteriological oxidation of phenols in aerated reaction vessels on a continuous flow basis, with a loading of approximately 1600 to 2400 kg/1000 m3/day (100-150 Ib phenol/1000 ft3/day) and a MLSS of 2000 mg/1, found that with wastes con- taining up to 5000 mg/1 phenol, a two day retention period could produce removal efficiencies in excess of 90 percent. Because the investigators were working with a coke gasification plant waste, the liquor contained thiocyanates. Higher oxidation efficiencies could be achieved with a reduction of the thiocyanate in the waste. Gas chromatography indicated no phenolic end products of degradation with original waste being a mixture of 36 percent monohydric and 64 percent polyhydric phenols. Pruessner and Mancini (36) obtained a 99 percent oxidation efficiency for BOD in petrochemical wastes. Similarly, Coe (37) reported reductions of both BOD and phenols of 95 percent from petroleum wastes in bench-scale tests of the activated sludge process. Optimum BOD loads of 2247 kilo- grams/1000 m3 per day (140 pounds/1000 ft3 per dayjwere obtained. Coke plant effluents were successfully treated by Ludberg and Nicks (38), although some difficulty in start-up of the activated sludge system was experienced because of the high phenol content of the water. The complete mixed, activated sludge process was employed to process a high-phenolic wastewater from a coal-tar distilling plant in Ontario (39). Initial phenol and COD concentrations of SOO and 6,000 mg/1Her, respec- tively, were reduced in excess of 99 percent for phenols and 90 percent for COD. Coal gas washing liquor was successfully treated by Nakashio (40) using activated sludge at a loading rate of 0.116 kg of phenol/kg MLSS/day. An influent phenol concentration of 1200 mg/1 was reduced by more than 99 percent in this year-long study. Similar phenol removal rates were obtained by Reid and Janson (41), in treating wastewaters generated by the washing and decarbonization of aircraft engine parts. Other examples of biological treatment of phenolic wastes include work by Putilena (42), Meissner (43) and Shukov, et. al. (44). Of particular interest is a specific test on the biological treat- ment of coke plant wastes containing phenols and various organics. In 22 ------- (O a: o o 1 _ Slope = K = 0.30 day"1 Le = La 1 + O.SOt 5 10 15 Aeration Time (Days) i 20 FIGURE 8. Determination of Reaction Rate Constant for a Creosote Wastewater 23 ------- a report of pilot scale and full scale studies performed by Kostenbader and Flacksteiner (45), the complete mixed activated sludge process achieved greater than 99.8 percent oxidation efficiency of phenols. Successful results were achieved with phenol loadings of 0.86 kg phenol/ kg MLSS/day with an equivalent BOD loading of 2 kg BOD/kg MLSS/day. In comparison, a typical activated sludge loading is 0.4 kg BOD/kg MLSS/ day. Effluent concentrations of phenol from the pilot plant were 0.2 mg/1 in contrast to influent concentrations of 3500 mg/1. Slight varia- tions in process efficiency were encountered with varying temperatures and loading rates. Phosphoric acid was added to achieve a phosphorus-to- phenol ratio of 1:70. At the termination of pilot plant work, a similar large scale treatment plant processing of 424 m3/day (112,000 gpd) was installed and resulted in an effluent containing less than 0.1 mg/1 of phenol. Dust and Thompson (46) conducted bench-scale tests of complete-mixed, activated sludge treatment of creosote and pentachlorophenol wastewaters using 5-liter units and detention times of 5, 10, 15, and 20 days. The operational data collected at steady-state conditions of substrate removal for the creosote waste are shown in Table 6. A plot of these data showed that the treatabUHy factor, K, was 0.30 days -1 (Figure 8). The resulting design equation, with t expressed 1n days, is: Lo Le * - + 0.30* A plot of percent COD removal versus detention time in the aerator based on the above equation, shown 1n Figure 9, Indicates that an oxidation efficiency of about 90 percent can be expected with a detention time of 20 days 1n units of this type. TABLE 6. SUBSTRATE REMOVAL AT STEADY-STATE CONDITIONS IN ACTIVATED SLUDGE UNITS CONTAINING CREOSOTE WASTEWATER Aeration Time, Days 5.0 10.0 14.7 20.1 COD Raw, mg/1 COD Effluent, mg/1 % COD Removal COD Raw/COD Effluent 447 178 60.1 2.5 447 103 76.9 4.3 442 79 82.2 5.6 444 67 84.8 6.6 Work was conducted to determine the degree of biodegradabillty of pentachlorophenol waste. Cultures of bacteria prepared from soil removed from a drainage ditch containing pentachlorophenol waste were used to inoculate the treatment units. Feed to the units contained 10 mg/liter 24 ------- o o 90 80 o 70 o e IN} en a o o « a. 60 2 50 Lo 0.30* 40 10 Aeration Time (Days) 15 20 FIGURE 9. COD Removal from a Creosote Wastewater by Aerated lagoon without Sludge Return ------- of pentachlorophenol and 2,400 mg/1iter COD. For the two 5-liter units (A and B) the feed was 500 and 1000 ml/day and detention times were, in order, 10 and 5 days. Removal rates for pentachlorophenol and COD are given in Table 7. For the first 20 days. Unit A removed only 35 percent of the pentachlorophenol added to the unit. However, removal increased dramatically afterward and averaged 94 percent during the remaining 10 days of the study. Unit B consistently removed over 90 percent of the pentachlorophenol added. Beginning on the 46th day and continuing through the 51st day, pentachlorophenol loading was increased at two-day intervals to a maximum of about 59 mg/liter. Removal rates for the three two-day periods of increased loadings were 94, 97, and 99 percent. COD removal for the two units averaged about 90 percent over the duration of the study. Also working with the activated sludge process, Kirsh and Etzel (47) obtained removal rates for pentachlorophenol in excess of 97 percent using an 8-hour detention time and a feed concentration of 150 mg/liter. The pentachlorophenol was supplied to the system in a mixture that included 100 mg/liter phenol. Essentially complete decomposition of the phenol was obtained, along with a 92 percent reduction in COD, TABLE 7. REDUCTION IN PENTACHLOROPHENOL AND COD IN WASTEWATER TREATED IN ACTIVATED SLUDGE UNITS RAW EFFLUENT FROM UNIT WASTE (% Removal) DAYS (rag/1) "A" "B" COD 1-5 6-10 11-15 16-20 21-25 26-30 31-35 2350 2181 2735 2361 2288 2490 2407 78 79 76 82 90 — 83 78 79 75 68 86 84 80 PENTACHLOROPHENOL 1-5 7.9 20 77 6-10 10.2 55 95 11-15 7.4 33 94 16-20 6.6 30 79 21-25 7.0 - 87 26-30 12.5 94 94 31-35 5.8 94 91 36-40 10.3 -- 91 41-45 10.0 ~ 96 46-47 20.0 ~ 95 48-49 30.0 — 97 50-51 40.0 - 99 -26- ------- Cooper and Catchpole (48) reported greater than 95 percent oxidation of phenols using activated sludge units treating coke plant effluents containing phenols, thiocyanates, and sulfides. Adequate^data were not available on the detailed operating parameters of the activated sludge plant. Trickling Filters Hsu, Yany, and Weng (49) reported successful treatment of coke plant phenolic wastes with a trickling filter, removing over 80 percent of the phenols. It was stated that influent phenol concentrations should not exceed 100 mg/1. Using a Surfpac trickling filter, Francingues (50) was able to remove 80 to 90 percent of the influent phenol from a wood preserving creosote wastewater at a loading rate of about 16 kg/1000 m3/day (1 Ib phenol/ 1000 ft3/day). Sweets, Hamdy, and Weiser (51) studied the bacteria responsible for phenol reductions in industrial waste and reported good phenol removal from synthesized waste containing concentrations of 400 mg/1. Reductions of 23 to 28 percent were achieved in a single pass of the wastewater through a pilot trickling filter having a filter bed only 30 centimeters (12 inches) deep. Waters containing phenol concentrations of up to 7500 mg/1 were suc- cessfully treated in laboratory tests conducted by Reid and Libby (52). Phenol removals of 80 to 90 percent were obtained for concentrations on the order of 400 mg/1. Their work confirmed that of Ross and Shepard (531 who found that strains of bacteria isolated from a trickling filter could survive phenol concentrations of 1600 mg/liter and were able to oxidize phenols in concentrations of 450 mg/liter at better than 99 percent efficiency. Reid, Wortman, and Walker (54) found that many pure cultures of bacteria were able to live in phenol concentrations of up to 200 mg/1, but few survived concentrations above 900 mg/1, although some were grown in concentrations as high as 3700 mg/1. Harlow, Shannon.and Sercu (55) described the operation of a commercial-size trickling filter containing "Dowpac" filter medium that was used to process wastewater containing 25 mg/1 phenol and 450 to 1900 mg/1 BOD. Reductions of 96 percent for phenols and 97 percent for BOD were obtained in this unit. Their results compare favorably -with those reported by Montes, Allen, and Schowell (56) who obtained BOD reductions of 90 percent in a trickling filter using a 1:2 recycle ratio, and Dickerson and Laffey (57), who obtained phenol and BOD reduc- tions of 99.9 and 96.5 percent, respectively, in a trickling filter used to process refinery wastewater. A combination biological waste-treatment system employing a trickling filter and an oxidation pond was reported on by Davies, Biehl, and Smith (58). The filter, which was packed with a plastic medium, was used for a roughing treatment of 10.6 million liters (2.8 million gallons) of wastewater per day, with final treatment occurring in the oxidation pond. Removal rates of 95 percent for phenols and 60 percent for BOD -27- ------- were obtained in the filter, notwithstanding the fact that the pH of the influent averaged 9.5. A study of biological treatment of refinery wastewaters by Austin, Meehan, and Stockham (59) employed a series of four trickling filters with each filter operating at a different recycle ratio. The waste contained 22 to 125 mg/liter of oil and this adversely affected BOD removal. However, phenol removal was unaffected by oil concentrations within the range studies. Prather and Gaudy (60) found that significant reductions of COD, BOD, and phenol concentrations in refinery wastewater were achieved by simple aeration treatments. They concluded that this phenomenon accounted for the high allowable loading rates for biological treatments such as trickling filtration. The practicality of using trickling filters for secondary treatment of wastewaters from the wood preserving industry was explored by Dust and Thompson (46). Creosote wastewater was applied at BOD loading rates of from 400 to 3050 kilograms/1000 m3 per day (25 to 190 pounds/ 1000 ft3 per day) to a pilot unit containing a 6.4 meter (21 feet) filter bed of plastic media. The corresponding phenol loadings were 1.6 to 54.6 kMograms/1000 m3 per day (0.1 to 3.4 pounds/1000 ft3 per day). Raw feed-to-recycle ratios varied from 1:7 to 1:28. Daily samples were analyzed over a period of seven months that included both winter and summer operating conditions. Because of wastewater charac- teristics at the particular plant cooperating in the study, the following pretreatment steps were necessary: (a) equalization of wastes; (b) pri- mary treatment by coagulation for partial solids removal; (c) dilution of the wastewater to obtain BOD loading rates commensurate with the range of raw flow levels provided by the equipment; and (d) addition to the raw feed of supplementary nitrogen and phosphorus. Dilution ratios of 0 to 14 were used. The efficiency of the system was essentially stable for BOD loadings of less than 1200 kilograms/1000 m3 per day (75 lbs/1000 ft3 per day). The best removal rate was achieved when the hydraulic application rate was 2.85 Ipm/m2 (0.07 gpm/ft2) of raw waste and 40.7 Ipm/m2 (1.0 gpm/ft2) of recycled waste. The COD, BOD, and phenol removals obtained under these conditions are given in Table 8. Table 9 shows the relationship between BOD loading rate and removal efficiency. BOD removal efficiency at loading rates of 1060 kilograms/ 1000 m3 per day (66 pounds/1000 ft3 per day) was on the order of 92 percent, and was not improved at reduced loadings. Comparable values for phenols at loading rates of 19.3 kilograms/1000 m3 per day (1.2 pounds/ 1000 ft3 per day) were about 97 percent. Since phenol concentrations were more readily reduced to levels compatible with existing standards than were BOD concentrations, the sizing of commercial units was based on BOD removal rates. Various combinations of filter-bed depths, tower diameters, and volumes of filter media that were calculated to provide a BOD removal rate of 90 percent for an Influent having a BOD of 1500 mg/liter are shown in Table 10 for a plant with a flow rate of 75,700 Ipd (20,000 gpd). -28- ------- TABLE 8. BOD, COD, AND PHENOL LOADING AND REMOVAL RATES FOR PILOT TRICKLING FILTER PROCESSING A CREOSOTE WASTEWATER Measurement BOD Characteristics TOD Phenol Raw Flow Rate Iprn/m2 (gpm/ft2) Recycle Flow Rate 1 pro/in2 (gpm/ft2) 2.85 (0.07) 40.7 (1.0) 2.85 (0.07) 40.7 0.0) 2.85 (0.07) 40.7 (1*0) Influent Concentration (mg/1) 1698 3105 31 Loading Rate gm/m3/day Effluent Concentration (mg/1) Removal (%} 1075 (66.3) 137 91.9 1967 (121.3) 709 77.0 19.5 (1.2) <1.0 99+ 29 ------- TABLE 9. RELATIONSHIP BETWEEN BOD LOADING AND TREATABILITY FOR PILOT TRICKLING FILTER PROCESSING A CREOSOTE WASTEWATER BOD Loading kg/cu m 373 421 599 859 1069 1231 1377 1863 2527 a Based BOD Loading (Ib/cu ft. /day) (23) (26) (37) (53) (66) (76) (85) (115) (156) on the equation: E§ = eKD/ Removal Treatability a («) Factor 91 95 92 93 92 82 80 75 62 Q °'5 (Germain, 1966) 0.0301 0.0383 0.0458 0.0347 0.0312 0.0339 0.0286 0.0182 0.0130 in which Le = BOD concentration of settled effluent, Lp = BOD of feed, Q = hydraulic application rate of raw waste in gpm/ft^, D = depth of media in feet, and K = treatability factor (rate coefficient). 30 ------- TABLE 10. SIZING OF TRICKLING FILTER FOR A WOOD PRESERVING PLANT (NOTE: Data are based on a flow rate of 75,700 liters per day (20,000 gallons per day), with filter influent BOD of 1500 and effluent BOD of 150 mg/1). Depth of filter bed m (ft) Raw Flow 1 pm/m2 (gpm/ft2) filter surface) Recycle flow 1 pm/m2 (gpm/ft2) filter surface) Filter Surface area (ft2) Tower dia m (ft) Vol ume of media uj3 (ft3) 3.26 (10.7) 3.81 (12.5) 4.36 (14.3) 4.91 (16.1) 5.46 (17.9) 5.97 (19.6) 6.52 (21.4) 0.774 (0.019) 1.059 (0.206) 1.385 (0.034) 1.793 (0.044) 2.200 (0.054) 2.648 (0.065) 3.178 (0.078) 29.7 (0.73) 29.3 (0.72) 28.9 (0.71) 28.5 (0.70) 28.1 (0.69) 27.7 (0.68) 27.3 (0.67) 65.8 (708) 48.3 (520) 37.0 (398) 29.3 (315) 23.7 (255) 19.5 (210) 16.4 (177) 9.14 (30.0) 7.83 (25.7) 6.86 (22.5) 6.10 (20.0) 5.49 (18.0) 4.97 (16.3) 4.57 (15.0) 213 (7617) 183 (6529) 160 (5724) 142 (5079) 128 (4572) 116 (4156) 107 (3810) Oxidation Ponds The American Petroleum Institute's "Manual on Disposal of Refinery Wastes" (61) refers to several industries that have successfully used oxidation ponds to treat phenolic wastes. Montes (62) reported on results of field studies involving the treatment of petrochemical wastes using oxidation ponds. He obtained BOD reductions of 90 to 95 percent in ponds loaded at the rate of 84 kilograms of BOD per hectare per day (75 pounds/acre/day). 31 ------- Phenol concentrations of 990 mg/liter in coke oven effluents were reduced to about 7 mg/liter in field studies of oxidation ponds conducted by Biczyski and Suschka (63). Similar results have been reported by Skogen (64) for a refinery waste. The literature contains operating data on only one pond used for treating wastewater from wood preserving operations (65, 66, 67). This is the oxidation pond used as part of a waste treatment system by Weyerhaeuser Company at its DeQueen, Arkansas, wood preserving plant. As originally designed and operated in the early 1960's, the DeQueen waste treatment system consisted of holding tanks into which water from the oil-recovery system flowed. From the holding tanks the water was sprayed into a terraced hillside from which it flowed into a mixing chamber adjacent to the pond. Here it was diluted 1:1 with creek water, fortified with ammonia and phosphates, and discharged into the pond proper. Retention time in the pond was 45 days. The quality of the effluent was quite variable, with phenol content ranging up to 40 mg/liter. In 1966, the system was modified by installing a raceway containing a surface aerator and a settling basin in a portion of the pond. The discharge from the mixing chamber now enters a raceway where it is treated with a floc- culating agent. The floe formed collects in the settling basin. Detention time is 48 hours in the raceway and 18 hours in the settling basin from which the wastewater enters the pond proper. These modifications in effect changed the treating system from an oxidation pond to a combination aerated lagoon and polishing pond. The effect on the quality of the effluent was dramatic. Figure 10 shows the phenol content at the outfall of the pond before and after installation of the aerator. As shown by these data, phenol content decreased abruptly from an average of about 40 mg/liter to 5 mg/liter. Even with the modifications described, the efficiency of the system remains seasonally dependent. Table 11 give phenol and BOD values for the pond effluent by month for 1968 and 1970. The smaller fluctuations in these parameters in 1970 as compared with 1968 indicate a gradual improvement in the system. Soil Irrigation The principal feature of the soil irrigation method of waste- water treatment is its simplicity. Water that has been freed of surface oils and, depending upon the presence of emulsified oils, treated with flocculated chemicals and filtered through a sand bed is simply sprayed onto a prepared field. Soil microorganisms decompose the organic matter in the water in much the same fashion as occurs in more conventional waste treatment systems. In addition to its simplicity, soil irrigation has the advantage of low capital investment (exclusive of land costs), low operating and maintenance costs, requires a minimum of mechanical equipment, 32 ------- CO co 45 40 35 30 25 Q> o o 1 15 0) 10 JAN FEB MAR APR MAY JUNE JULY AUG SEPT OCT NOV DEC Month Figure 10. Phenol Content in Oxidation Pond Effluent Before and After Installation in June 1966 of Aerator ------- and produces a high-quality effluent in terms of color, oxygen demand, and other pertinent parameters. Its chief disadvantage is that its use requires a minimum of approximately one acre for an application rate of 13,250 Ipd (3500 gpd). This limitation makes soil irrigation practical only in areas where land is available and relatively in- expensive. TABLE 11. AVERAGE MONTHLY PHENOL AND BOD CONCENTRATIONS IN EFFLUENT FROM OXIDATION POND (mg/liter) 1968 Month January February March April May June July August September October November December Phenol 26 27 25 11 6 5 7 7 7 16 7 11 BOD 290 235 190 150 100 70 90 70 110 150 155 205 1970 Phenol 7 9 6 3 1 1 1 1 1 - - - BOD 95 140 155 95 80 60 35 45 25 - - - Several applications of wastewaters containing high phenol con- centrations to soil irrigation have been reported. One such report, by Fisher (68) related the use of soil irrigation to treat wastewaters from a chemical plant that had the following characteristics: pH 9 to 10 Color 5,000 to 42,000 units COD 1,600 to 5,000 mg/liter BOD 800 to 2,000 mg/liter -34- ------- Operating data from a 0.81 hectare (2 acre) field, when irrigated at a rate of 7570 liters (2,000 gal) per acre/day for a year, showed color removal of 88 to 99 percent and COD removal of 85 to 99 percent. The same author reported on the use of this method to treat effluent from two tar plants that contained 7,000 to 15,000 mg/liter phenol and 20,000 to 54,000 mg/liter COD. The waste was applied to the field at a rate of about 9460 liters (2500 gal) per acre/day. Water leaving the area had COD and phenol concentrations of 60 and 1 mg/liter, respectively. Based on the lower influent concentration for each parameter, these values represent oxidation efficiencies of well over 99 percent for both phenol and COD. Bench-scale treatment of coke plant effluent by soil irrigation v/as also studied by Fisher. Wastes containing BOD and phenol concen- trations of 5,000 and 1,550 mg/liter, respectively, were reduced by 95+ and 99+ percent when percolated through 0.9 meters (36 inches) • of soil. Fisher pointed out that less efficient removal was achieved with coke-plant effluents using the activated sludge process, even when the waste was diluted with high-quality water prior to treatment. The effluent from the units had a color rating of 1,000 to 3,000 units, compared to 150 units for water that had been treated by soil irrigation. Both laboratory and pilot scale field tests of soil-irrigation treatments of wood preserving wastewater were conducted by Dust and Thompson (46). In the laboratory tests, 210-liter (55 gallon) drums containing a heavy clay soil 60-centimeters (24 inches) deep were loaded at rates of 32,8000, 49,260, and 82,000 liters/hectare/day (3,500, 5,250, and 8,750 gallons/acre/day). Influent COD and phenol concentrations were 11,500 and 150 mg/liter, respectively. Sufficient nitrogen and phosphorus were added to the waste to provide a COD:N:P ratio of 100:5:1. Weekly effluent samples collected at the bottom of the drums were analyzed for COD and phenol. Reductions of more than 99 percent in COD content of the wastewater were attained from the first week in the case of the two highest loadings and from the fourth week for the lowest loading. A break- through occurred during the 22nd week for the lowest loading rate and during the fourth week for the highest loading rate. The COD removal steadily decreased thereafter for the duration of the test. Phenol removal showed no such reduction, but instead remained high throughout the test. The average test results for the three loading rates are given in Table 12. Average phenol removal was 99+ percent. Removal of COD exceeded 99 percent prior to breakthrough and averaged over 85 percent during the last week of the test. The field portion of Dust and Thompson's (46) study was carried out on an 0.28-hectare (0.8 acre) plot prepared by grading to an approximately uniform slope and seeded to native grasses. Wood preserving wastewater from an equalization pond was applied to the field at the rate of 32,800 liters/hectare/day (3,500 gallons/acre/day) for a period of nine months. Average monthly influent COD and phenol concentrations ranged from 2,000 to 3,800 mg/liter and 235 to 900 mg/liter, respectively. Supplementary nitrogen and phosphorus were 35 ------- not added. Samples for analyses were collected weekly at soil depths of 0 (surface),30, 60, and 120 centimeters (1, 2, and 4 feet). The major biological reduction in COD and phenol content occurped at the surface and in the upper 30 centimeters (1 foot) of soil. A COD reduction of 55.0 percent was attributed to overland flow. The comparable reduction for phenol content was 55.4 percent (Table 13), COD reductions at the three soil depths, based on raw waste to the field, were 94.9, 95.3, and 97.4 percent, respectively, for the 30-, 60-, and 120 centimeter (1-, 2-, and 4-foot) depths. For phenols, the reductions were, in order, 98.9, 99.2, and 99.6 percent. TABLE 12. RESULTS OF LABORATORY TESTS OF SOIL IRRIGATION METHOD OF WASTEWATER TREATMENT* Loading Rate (Liter/ha/day) 32,800 (3,500) 49,260 (5,250) 82,000 (8,750) Length of Test (Week) 31 13 14 Avg. & COD Removal to Breakthrough 99.1 (22 wks) 99.6 99.0 (4 wks) COD REMOVAL Last Week of Test % 85.8 99.2 84.3 Phenol Avg. % Removal (All Weeks) 98.5 99.7 99.7 Loading rates in parentheses in gallons/acre/day Creosote wastewater containing 11,500 mg/liter of COD and 150 mg/Hter of phenol was used. Activated Carbon Filtration Activated carbon is used commercially to treat petroleum (69) and other types (70) of Industrial wastewaters. It can also be used effectively to remove phenolic compounds from wood preserving waste streams. Although carbon has a strong affinity for nonpolar compounds such as phenols, adsorption is not limited to these materials. Other organic materials in wastewater are also adsorbed, resulting in a decrease in the total oxygen demand of the waste. Because the concen- tration of the latter substances exceeds that of phenols in effluents from wood preserving plants, the useful life of activated carbon is determined by the concentration of these materials and the rate at which they are adsorbed. 36 ------- TABLE 13. REDUCTION OF COD AND PHENOL CONTENT IN WASTEWATER TREATED BY SOIL IRRIGATION Soil Depth (centimeters) Month Raw Waste July August September October November December January February March April Average % Removal (weighted) July August September October November December January February March April 2235 2030 2355 1780 2060 3810 2230 2420 2460 2980 235 512 923 310 234 327 236 246 277 236 0 COD (mg/1) 1400 1150 1410 960 1150 670 940 580 810 2410 55.0 Phenol (mq/1) 186 268 433 150 86 6 70 in 77 172 30 ••» • — -- 150 170 72 121 144 101 126 94.9 MM — « 4.6 7.7 1.8 1.9 4.9 2.3 1.9 60 M m. — — — 170 91 127 92 102 — 95.3 .. — ~ _. 3.8 9.0 3.8 2.3 1.9 0.0 120 66 64 90 61 46 •58 64 64 68 76 97.4 1.8 0.0 0.0 2.8 0.0 3.8 0.0 1.8 1 .3 0.8 Average % Removal (weighted) 55.4 98.9 99.2 99.6 37 ------- Results of carbon-adsorption studies conducted by Dust and Thompson (46) on a creosote wastewater are shown in Figure 11. Granular carbon was used and the contact time was 24 hours. The wastewater was floccu- lated with ferric chloride and its pH adjusted to 4.0 prior to exposure to the carbon. As shown in the figure, 96 percent of the phenols and 80 percent of the COD were removed from the wastewater at a carbon dosage of 8 g/liter. The loading rate dropped off sharply at that point, and no further increases in phenol removal and only small increases in COD removal occurred by increasing carbon dosage to 50 gm/liter. Similar results were obtained in tests using pentachlorophenol wastewater. Results of adsorption isotherms that were run on pentachlorophenol wastewater, and other samples of creosote wastewater followed a pattern similar to that shown in Figure 11. In some instances a residual content of phenolic compounds remained in wastewater after a contact period of 24 hours with the highest dosage of activated carbon employed, while in other instances all of the phenols were removed. Loading rates of 0.16 kilograms of phenol and 1.2 kilograms of COD per kilogram of carbon were typical, but much lower rates were obtained with some wastewaters. Miscellaneous Treatment and Handling Methods Wastes from wood preserving plants may also be handled by containment, if adequate land is available, by spray evaporation, if a relatively high operating cost can be tolerated, or by heat evaporation or incinera- tion if the waste stream is small. SUMMARY It was concluded that previous laboratory and pilot work demonstrated that chemical or biological action could be used to reduce wastewater pentachlorophenol concentration. Pentachlorophenol is more toxic than simple creosote but less soluble in water. High concentrations of pentachlorophenol can be oxidized to harmless, biodegradable chloranyls. Low concentration of pentachlorophenol, on the order of 10 to 30 mg/1, can be degraded biologically in the presence of relatively numerous nutrients. Some portion of the Carbondale plant's wastewater could, therefore, be degraded in an activated sludge system, probably including the pnetachlorophenol and creosote fractions. Ample evidence was found in the literature to substantiate destruc- tive chlorination and biological oxidation of phenolic compounds. Thus, while there remained some ambiguity concerning the detailed operating parameters for a treatment plant for these wastes, the basic processes were sound. It was felt that early ambiguities arose from non-parametric studies with varying feed waters, few of which were specifically wood preserving wastewaters. It was the intent of the Carbondale study to clarify the various operating parameters and provide a sound basis for future design work. 33 ------- 10CH 10 20 30 Activated Carbon (gm/liter) FIGURE 11 Relationship Between Weight of Activated Carbon Added and Removal of COD and Phenols from a Creosote Wastewater 39 ------- SECTION V MATERIALS AND METHODS Following acceptance of the grant application, laboratory and field studies were begun in Carbondale to establish wastewater flow and characteristics. A mobile laboratory was stationed on-site for a five day period during which samples were collected and analyzed. Flow measurements were initiated and continued for a two month period. A discussion of data collection methods and of development of design parameters are presented in this section. PRE-DESIGN STUDIES At the time of the pre-design wastewater studies, condensate from the treating cylinders was pumped to primary separation tanks. The pentachlorophenol condensate which is isolated from the creosote waste stream receives polymer addition before going to the secondary penta separator. Since penta-oil is lighter than water, skimming allows good separation. The creosote condensate, after polymer addition, was separated by settling the heavier creosote and skimming the light oils. The two waste streams were then combined in a common sump and pumped to Pond 2 or Pond 3. The effluents from Ponds 2 and 3 flowed to a Pond 4 by gravity. Pond 1 was maintained for emergency use only. Previous to the present design, these ponds, together with the primary oil removal and preservation recovery system and a 1.05 hectare (2.58 acre) irrigation field constituted the waste treatment facilities for the Carbondale plant. The wastewater flow during the pre-design study averaged 27,055 1 pd (7,148 gpd) of which 36 percent was penta waste and 64 percent creosote waste. The range and variability of the total wastestream and the constituent flows is illustrated in Figure 12. Obviously, the flow- rate was erratic, varying from less than one-fourth to nearly three times the average daily flow. Of importance is the fact that penta flow was non-existent for several consecutive days and then occurred in slug flows. The analytical data collected during the five day sampling period is presented in Table 14. Each pond was sampled during this period; however, due to inplant modifications, it was decided that the pond data was of little value for design. The samples considered to be of value were those from the creosote decantor effluent and the common sump. During the period of sampling, there was no flow for at least two days from the penta separator and, therefore, the concentrations determined in the commom sump are not necessarily average concentrations. A better estimate of average conditions is obtained by calculating con- centrations based on the preparation of average flow from each waste source. This calculated average is also shown in Table 14. 40 ------- 20,250 10,160 COMBINED WASTE FLOW O PENTACHLOROPHENOL WASTE MISSING DATA POINT IS l« 17 18 19 20 21 22 23 24 25 26 27 29 Z9 30 FIGURE 12. Time/Days Flowrate Variation with Time ------- TABLE 14. Analytical Data From Pre-Design Study ro Date 6-25 6-26 6-27 6-28 6-29 Sample Point Creosote Effluent Penta Effluent Common Sump Creosote Effluent Penta Effluent Penta Effluent Creosote Effluent Penta Effluent Common Sump Creosote Effluent Penta Effluent Common Sump COD (mg/1) 2,130 4,360 2,130 7,800 6,900 - 7,990 4,720 7,260 3,209 4,972 2,621 BOD5 (rag/T) 615 1,335 600 525 1,395 - - - - 1,200 2,512 - TS (mg/1) 4,270 20,780 5,480 5,220 19,830 - 5,400 19,980 7,250 4,184 19,844 4,447 TSS (mg/1) 147 156 181 70 138 - 58 143 56 142 158 174 Phenol (mg/D 100 50 120 140 65 - 132 70 140 200 - - Oil and Grease NH3+-N Total (mg/1) (mg/1) (mg/1) pH 89 550 3,200 5.6 4.9 5.6 96 500 3,050 5.6 178 1,750 10,200 4.7 263 1,650 11,200 5.6 4.9 5.4 275 500 2,050 5.7 4.8 5.7 ------- TABLE 14. ANALYTICAL DATA FROM PRE-DESIGN STUDY Sample Date Point Average creosote effluent Penta Effluent Common Sump COD (mg/1 ) 5,282 5,238 4,004 BOD5 (mg/T) 780 1,747 600 TS (mg/1) 4,769 20,109 5,726 TSS (mg/1) 104 149 137 Phenol (mg/1) 143 78 130 Oil and Grease (mg/1) 153 221 _ NH3+-N (mg/1) 517 1,700 _ Total (mg/1) 2,767 10,700 _ pH 5.6 4.8 5.6 oo CALCULATED AVERAGE CONCENTRATIONS OF COMBINED EFFLUENTS 5,266 1,126 10,291 121 120 178 943 5,623 5.3 ------- The ratio of BOD to COD for the calculated average data was relatively low, possibly indicating some degree of biological inhibition. Figure 13 shows the effluent dilution of the BOD test. When the dilution factor was increased from 99.6 to 99.9 percent, the BOD of the penta effluent increased from 1860 to 3500 mg/1. An increase in dilution from 99.8 to 99.9 percent for the creosote effluent resulted in a BOD increase from 1000 to 2000 mg/1. Assuming the samples were properly seeded, the value of the BOD test becomes questionable. While a limited amount of BOD data was collected during the study and is presented in this report where appropriate; the limitations on its usefulness should be noted in light of the above discussion. The majority of the solids, as noted in Table 14, are composed of dissolved material which resulted for the most part from salts in fire retardant compounds which contained ammonium phosphate, ammonium sulfate, sodium tetraborate and boric acid as their primary constituents. Analyses performed later showed high boron levels. Also, the nutrient levels were relatively high due to the use of the fire retardant. The plant, subsequent to thepre-designed study, terminated the use of fire retardant preservative although boron persisted in the effluent for a period of time. The phenol concentration averaged 120 mg/1 during the study while the oil and grease concentration was 178 mg/1 and pH averaged 5.3. No analytical data is given in Table 14 for penta because at the time of the pre-design study no suitable analysis technique had been developed. Later analyses by Koppers personnel indicated that the penta concentration was less than 20 mg/1. DEVELOPMENT OF PARAMETERS The average conditions determined in the pre-design study were chosen as the hydraulic basis for design. The average daily flow used for design was 27,063 Ipd (7150 gpd) or 19 1pm (5 gpm). Further, it was decided that by maintaining Pond 2 as a surge lagoon it would be possible to operate the treatment facility at a constant feed rate and minimize the problems associated with flowrate and quality variations. The pre-design data indicated that primary and secondary preserva- tive recovery was efficiently removing most of the separable oils from the effluent. For this reason no modification of the existing oil re- moval system was considered necessary. Laboratory studies by Thompson (46) and others indicated that biological oxidation of penta was possible. However, due to uncertainty with regard to the degree of reduction possible, the maximum concentration allowable, and the effects of penta on a biological system treating a complex, heterogeneous wastewater, it was decided that pretreatment with chlorine should be included in the design. Preliminary tests indicated that several hours detention time would reduce the chlorine residual to minimal levels. For this reason no chlorine removal facili- ties were included in the design of the pre-chlorination section of the treatment system. 44 ------- 4000- PENTACHLOROPHENOL EFFLUENT 3000 2000' a o m LU 1000- CREOSOTE EFFLUENT 99.6 99.7 ^DILUTION 99.8 99.9 100.0 FIGURE 13, Percent Dilution vs. BOD 45 ------- On the basis of the limited information in the literature, recent laboratory data, and the consultant's experience with biological treat- ment, the system with the best potential for success was judged to be complete mix activated sludge. This process, having a record of success in many industrial applications, has the advantage of reducing the effects of shock loadings. Additionally, it requires relatively little land area and is a viable treatment alternative for wood preserving plants with little available space. The determination of design parameters was based on experience with the activated sludge process and on the limited laboratory and literature data relative to wood preserving wastes. It was felt that the design should be based on the assumption that pre-chlorination might not be necessary. Therefore, all loadings, detention times, and capacities were based on the data shown in Table 14 of this section. The factor considered most important with regard to organic loading rates was the penta concentration in the mixed liquor. Laboratory results had shown biological degradation of penta at loadings of 1.62 gm/m3 (0.1 lb/1000 cu ft) of aeration volume (71). Slug loads of 6.5 gm/nr (0.4 lb/1000 cu ft) had been tolerated in the same study. This is equivalent to an average loading of 4.2 kg penta/kkg MLSS with shock loadings up to 16.9 kg penta/kkg MLSS. Considering that this waste also contains phenols in excess of 100 mg/1, a conservative loading rate of 2 kg penta/kkg MLSS was chosen. Assuming a penta concentration of 20 mg/1 and a mixed liquor concentration of 3000 mg/1 resulted in a required aeration volume of about 83,270 liters (22,000 gallons) and a hydraulic detention time exceeding three days, the corresponding BOD loading (usinq the calculated average from Table 14 which was assumed to be valid) was a conservative 0.1 kg BOD/kg MLSS. The phenol loading rate was about 0.01 kg phenol/kg MLSS, which was considerably less that the maximum loadings recorded in the literature for wastewaters not con- taining penta. With these conservative design parameters and with the further safeguard of pre-chlorination, it was felt that satisfactory results could be obtained. Due to the lack of field information on the necessary dosages of chlorine for pre-chlorination and post-chlorination, precise design parameters could not be defined. The pre-chlorination dosage capability was therefore designed to range from 0 to 4000 mg/1 and the post- chlorination from 0 to 400 mg/1. DESIGN AND CONSTRUCTION The basic units required for effective chemical and biological treatment of the wastewater based on the parameters developed above and with as much flexibility as possible due to the experimental nature of the project, were considered to be as follows: 1. Surge or equalization basin. The existing Pond #2 was suitable for this purpose. 2. Influent pump. A small centrifugal pump with a maximum capacity of 37,850 Ipd (10,000 gpd) mounted on a floating platform in Pond #2 was considered adequate. 46 ------- 3. Flow measurement and control device. The small flow could be easily measured with a rotameter and controlled with a valve. 4. Pre-chlorination unit. Total detention time equaling 12 hours with baffling for varying detention times and by-pass capability. 5. Aeration tank. A total volume of at least 83,290 Ipd (22,000 gallons) should be divided into two or more sections for varying loading rates. 6. Final clarifier. An overflow rate of 8150 to 12,200 Ipd/m2 (200 to 300 gpd/ft2) was considered necessary. 7. Post chlorination tank. A detention time of 8 to 10 hours was provided. 8. Chlorine injector equipment. A variable feed rate up to 91 kg/day (200 Ib/day) was provided. 9. Aerobic digester. A retention period of 15 to 20 days was allowed. 10. Final sludge disposal was to be by irrigation on an existing field. A package unit was delivered by Davco in January 1973. As illus- trated in Figure 14, the treatment plant consisted of two rectangular tanks and a separate circular clarifier. The first rectangular tank, 3.66 m (12 ft) wide by 9.75 m (32 ft) long, was divided into an aerobic digestion tank and pre-chlorination tank, each approximately 1.83 m (6 ft) in length, and the #1 aeration tank which was about 6.1 m (20 ft) long. The secorvd tank was 2.44 (8 ft) wide by 11.6 m (38 ft) long and was divided into two sections, the #2 aeration tank which was about 7.9 m (26 ft) long, and the post chlorination tank which was about 1.83 m (6 ft) long. The clarifier had a diameter of approximately 2.44 m (8 ft). Flow entered either the pre-chlorination chamber or moved directly to the aeration tank. At 19 1pm (5 gpm), the detention time in the pre-chlorination tank was about 15 hours. This tank was later baffled to provide variable detention times. The aeration time in the #1 tank was about 50 hours. All activated sludge was returned to this tank. The flow then entered aeration tank #2 which had a detention time of 47 hours at a flow of 19 1pm (5 gpm). The mixed liquor from tank #2 then settled in the clarifier which had a surface overflow rate of less than 6100 Ipd/sq m 150 gpd/sq ft) at the average design flow of 27,250 Ipd (7200 gpd). The clarifier overflow could be post chlorinated prior to final discharge. Air was supplied to the aeration tanks, aerobic digester, and the air lift sludge return line by a duplex blower driven by a 7.5 hp motor. The total expected air requirement was 5.2 cu m/min at 1.34 atm (185 cfm at 5 psig). The entire plant was placed on a reinforced concrete slab above ground. All extension surfaces were coated with insulating material to protect against severe winter weather. Heater tape was placed on exposed pipes and valves and electric immersion heaters were placed in the aeration tanks. 47 ------- INFLUENT 00 RETURN SLUDGE BLOWER DUPLEX AERATION TANK NO. 1 AERATION TANK NO. 2 BYPASS CLARIFIER AERATION TANK NO. 2 EFFLUENT FIGURE 14. Schematic of "Package" Treatment System ------- Due to the high nutrient levels observed in the pre-design study, no nutrient addition was provided in the final design. Control of pH, was not included in the final design. It was found that manual addition of lime to the aeration basins on an as needed basis would provide satisfactory pH control. In addition to the treatment plant itself, laboratory facilities were also constructed on-site. A full time chemist was employed to perform all analyses on-site with the exception of BOD tests which were conducted by an outside laboratory. A treatment plant operator was trained to maintain and operate the plant and also to assist in per- forming daily sample collections and analyses. PLAN OF OPERATION The original operating schedule developed for the project was based on the uncertainty of the effects of pentachlorophenol on the . activated sludge process. The original schedule is as follows: Month #1 - Chlorinate the effluent at 100 percent of chlorinator capacity using full detention time in prechlorination facility. With BOD loading equaling 0.1 kg BOD/day/kg MLSS, maintain MLSS around 3,000 mg/1. Post-chlorinate to produce an effluent phenol concentration of 0.1 mg/1. Month #2 - Reduce pre-chlorination to 50% of capacity or chlorinate only half of the influent stream at 100% capacity, other- wise, maintain steady-state conditions. Month #3 - Reduce pre-chlorination by 50% again, resulting in a total decrease since initial operation of 75%. Maintain con- stant conditions. Month #4 - Based on the previous three months of operation, dis- continue pre-chlorination entirely or operate at the miniumum level apparently required. Determine this level by ex- amining the condition of the biological process during the first three months. Also, study the effect of detention time on chlorination by collecting samples from each section of the baffled pre-chlorination tank. Month #5 - Maintain pre-chlorination at the minimum level determined above or increase it as necessary while doubling BOD and PCP loadings by halving the aeration tank volume. Also, attempt a 20% reduction in MLSS concentration. Month #6 - Pre-chlorinate as necessary while again reducing MLSS by 20%. After two weeks, if possible, reduce MLSS by another 20%. Month #7 - Pre-chlorinate as necessary while again reducing MLSS by 20% with further reductions if possible. Month #8 - Operate at steady state conditions utilizing the optimum pre- and post- chlorination dosages determined during the operating period, as well as the corresponding optimum BOD and penta loading rates. Although the package plant arrived in Carbondale in February 1973, because of inclement weather it was not ready for startup until July. 49 ------- Due to the delay, it was decided to initiate operation without pre- chlorination and thereby determine immediately whether chlorination would be required. On this basis, plant startup procedures were initiated on July 26, 1973. The aeration basins were filled with water from the emergency lagoon, Pond #1, which had low concentrations of boron, phenols, and penta. Bacterial inoculation was accomplished by placing horse manure into the aeration tank and aeration was begun. One week later a 23 1pm (6 gpm) feed mixture of emergency lagoon water and concentrated waste from Pond #2 was begun. By the middle of August the proportion of the mixture consisting of concentrated waste had been increased to 100 percent. Normal mechanical problems were encountered during the initial startup period. During the latter part of August, a pin sheared in the clarifier sludge rake mechanism and one pump failed. The sludge rake malfunction resulted in low MLSS concentrations throughout August. After the shear pin was replaced, the treatment plant was again placed in operation and startup was continued through September 1973. Because of the immediate success of the complete mix process with- out pre-chlorination, the entire operating schedule was modified. This revised schedule is shown in Table 15. Due to inclement weather and later mechanical failures, this schedule could not be adhered to exactly; however, all the desired objectives were accomplished during the study period. TESTING SCHEDULE The on-site laboratory was equipped with the necessary materials to perform basic gravimetric, colorimetric, and titrametric analyses including COD, solids, nutrients, phenols, pentachlorophenol, oil and grease, residual chlorine, pH, temperature, and dissolved oxygen. BOD analyses were performed by an outside laboratory and any special analyses required such as gas chromatography or metal analyses were performed elsewhere. Samples were collected daily for analysis. Batch samples were used instead of composites because of the presence of the large surge lagoon which minimized fluctuations and because of the large detention time in the treatment plant itself which tended to smooth out variations throughout the system. Due to the large number of analyses needed and the limited staff at Carbondale, a schedule of analyses based on the minimum requirements for experimentation and the manpower limitations had to be developed. The schedule shown in Table 16 was followed throughout the study period. During periods when more information was desired in one unit of the treatment system than another, more analyses were performed. For instance, when the effects of post-chlorination were being closely studied, more chlorine residual determinations were required. BOD, COD, phenol, solids, and oil and grease analyses were performed ac- cording to Standard Methods (13 edition) (72). Nutrients were analyzed 50 ------- TABLE 15. REVISED OPERATING SCHEDULE # 2 # 3 # 4 # 5 # 6 i 7 Objective Startup and shakedown Hydraulic loading variation Organic loading variation Increased organic loading Increased organic loading Post-chlorination studies Pre-chlorination studies # 8 Optimization Operation Inoculate aeration tanks with activated sludge or other bacteria source. Operate plant with increasing proportion of con- centrated waste and decreasing proportion of dilution water. Shakedown mechanical equipment, repairing and replacing as necessary. Increase the hydraulic loading to the treatment system in increments up to the limit of hydraulic capacity or organic loading rate, whichever is reached first. Restabilize the process at 4 to 6 gpm using only one aeration basin. Reduce the mixed liquor suspended solids or increase the flow rate incrementally. Continue reducing the MLSS or increasing the flow rate incrementally. Measure the effects of post-chlorination on PCP, phenol, COD and BOD concentrations at various dosages, increasing the dosage incrementally over the month. Operate the treatment plant at near constant conditions while increasing the pre-chlori- nation dosage incrementally and measuring its effect on the activated sludge process. Based on the previous months' experience, operate the process at those conditions which gave the best results including pre- and post-chlorination as necessary. 51 ------- TABLE 16. SCHEDULE OF ANALYSES Sampling Point and Number of Analyses Per Week Parameter BOD COD Phenol Penta TS TSS VSS TDS NH4+ P04= Influent 2 2 2 2 2 2 - 2 1 1 Prechlorination 1 1 1 1 - - - - - _ Aeration Basins 2 2 2 2 - 3 3 - - _ Clarifier Post Chlorination 1 2 1 2 1 2 1 2 2 2 - 2 1 1 SVI Oil and grease Temperature D.O. PH Residual 5 5 5 0-5 0-5 52 ------- with colorimetric kits. The determination of penta proved to be difficult and, in fact, no truly satisfactory method was found. The method chosen at the beginning of the study after careful evaluation of the two or three methods available was the Safram'n method which is a distillation and color development technique. 53 ------- SECTION VI RESULTS AND DISCUSSION The experimentation phase of the project was begun in July 1973, and was completed in May 1974. The raw data collected during the study is contained in the Appendix. PHASE 1 - START-UP AND STABILIZATION The start-up of the treatment system was accomplished with rela- tively little difficulty. Without the mechanical start-up problems encountered, the activated sludge process could have been stabilized in two weeks, but, with the mechanical problems, as previously discussed, the start-up and stabilization phase took about five weeks. A significant amount of data was not collected during the start-up period; however, most of the data obtained is presented in Table 17. The average influent and effluent concentrations of COD for the five week period were 1540 mg/1 and 410 mg/1, respectively, which is a reduction efficiency of 73 percent. The phenol reduction efficiency for the same period was 97 percent. The influent penta concentration was much less than expected but a reduction through the treatment system of 79 percent was obtained. PHASE 2 - STEADY STATE OPERATION For a period of about four weeks (August 30 through October 5, 1973), the treatment plant was operated at constant flow and loading to evaluate the performance of the activated sludge process under controlled conditions. During this phase, flowrate was maintained at 23 liters per minute (six gallons per minute), and influent COD averaged 178 mg/1, influent phenols averaged 88 mg/1, and influent penta averaged 1.7 mg/1. The average results of this period are pre- sented in Table 18 and, as can be seen, the effluent quality varied little during the four week period indicating a stable biological process. Effluent COD averaged 404 mg/1 and never varied more than 10 percent from this value. Effluent phenols rarely varied from the average value of 1 mg/1. The effluent PCP value never exceeded 0.6 mg/1 and averaged 0.4 mg/1. As it turned out, the loading rate was not constant because of sludge buildup. However, in general, it can be concluded from this data that a conservatively designed activated sludge process treating creosote and pentachlorophenol wastewater should be able to reduce COD by 75 to 80 percent, phenols by 95 to 99 percent, and PCP by 75 to 80 percent. PHASE 3 - LOADING RATE VARIATION Phase 2, Steady-State Operation, was terminated after the first week in October 1973. From that time until mid-November, experimenta- tion was directed primarily at examining the effects of loading rate variations on the activated sludge process. Due to the conservative design of the treatment system, a considerable degree of variation both in organic and hydraulic loading rate was possible. 54 ------- TABLE 17. STARTUP AND STABILIZATION DATA Date 1973 7-30 7-31 8-1 8-2 8-3 8-4 8-5 8-6 8-8 8-10 Flow, liters per minute Dilution Concentrated Sampling Water Waste Point 0 0 #1 Aeration Dilution Raw Waste 0 11,350 #1 Aeration #2 Aeration Effluent 0 0 #1 Aeration #2 Aeration Effluent 0 0 #1 Aeration #2 Aeration Effluent 17.0 1.89 Influent #1 Aeration #2 Aeration Effluent 15.1 3.8 Influent Effluent 13.2 5.7 Influent Effluent 11.4 7.6 Influent £1 Aeration #2 Aeration Effluent 3.8 15.1 Influent #1 Aeration #2 Aeration Effluent 3.8 15.1 Influent =1 Aeration r2 Aeration Effluent Parameter COD Phenols PCP (mg/1) (mg/1) (mg/1 ) 1 - 1 150 16 8 5 1 0.6 1 0.6 1 0.6 0.6 0.6 0.6 1 1 1 1 10 1 - 12 1 15 1 1 - 1 30 1 1 1 65 1.5 1.6 1.4 Sludge (ml/1) 0 _ - _ - _ M - 0.2 0.3 - 0.1 0.05 - •* - . - fm 0.1 0.1 - wm 0.1 0.1 - _ 0.3 0.4 _ 55 ------- TABLE 17. STARTUP AND STABILIZATION DATA Date 1973 8-16 8-17 8-20 Flow, liters per minute Dilution Water 3.8 1.9 0 Concentrated Waste 15.1 15.1 11.4 (Pump Problems) 8-21 8-23 0 0 7.6 11.4 (Pumps Required) 8-24 8-27 8-28 8-29 8-30 8-31 0 0 Clarifier Clarifier 0 0 15.1 22.7 paddles found Sampling COD Point (mg/1) Influent #1 Aeration #2 Aeration Effluent Influent #1 Aeration #2 Aeration Effluent Influent Effluent Influent 1,260 #1 Aeration #2 Aeration Effluent 350 Influent Effluent Influent Effluent Influent #1 Aeration #2 Aeration Effluent Parameter Phenols PCP (mg/1) (mg/1) 70 2 2 2 70 3 2 2 70 1 70 3.4 1.5 1.5 1.5 0.6 70 3.4 1.5 0.3 70 2.6 1 0.3 80 3 2 2 Sludge (ml/1) 0.7 0.6 - mm 0.5 0.4 - w - _ 0.4 0.4 - mm - _ - — 2.0 1.7 - to be not functioning paddles repaired 22.7 22.7 Influent 1,820 #1 Aeration $2 Aeration Effluent 470 Influent rl Aeration #2 Aeration Effluent 85 3.0 3 2 2 0.7 95 3 2 2 — 11.0 7.5 - — 13.0 9.5 _ 56 ------- TABLE 17. STARTUP AND STABILIZATION DATA Flow, liters per minute Parameter Date Dilution Concentrated Sampling CODPhenols PCPSludge 1973 Water Waste Point (mg/1) (mg/1 (mg/1) (ml/1) AVERAGE OF ALL STARTUP PERIOD Influent 1,540 56 2.9 34 #1 Aeration - 2-30 DATA n Aeration - 2 Effluent 410 2 0.6 43 P04 NH4+ Influent #1 Aeration #2 Aeration Effluent TABLE 18. EFFECTS OF Average Values from Steady Flow Rate Influent 22.7 1pm (6 gpm) Effluent Reduction Result of Shock Flow Rate 41.6 1pm (11 gpm) Influent Effluent Reduction SHOCK State COD 1784 404 77% 555 47.5 430 56.7 440 66.0 LOADING Operation - mg/1 Phenols 88 1 99% PCP 1.7 0.4 76% Loading COD 2650 710 73% Phenols 90 10 88% PCP 1.62 1.32 19% 57 ------- The effects of shock loading were observed during a three day period. The flowrate, which had been maintained at a constant 21 liters per minute (5.5 gpm) for over four weeks, was increased to 42 1pm (11 gpm) on October 8 and maintained at this rate for three days. At this rate, the nominal detention time in the aeration tanks was 44 hours, the BOD: MLSS ratio was about 0.13 kg BOD/kg MLSS, and the COD:MLSS ratio ex- ceeded 0.5 kg COD/kg MLSS. The penta loading was below 1 gm/cu m (0.06 Ib per 1000 cu ft) of aeration volume. While this is still far below the shock loadings of Thompson (46) — 6.5 gm/cu m (0.4 Ib per 1000 cu ft), the detention time was less than one-half of the five day detention used in his laboratory studies. The result of this increased loading and decreased detention time was a noticeable decrease in treat- ment efficiency as shown in Table 18. Phenol concentration increased rapidly in both aeration tanks as well as in the effluent. Phenol removal efficiency decreased from 99 percent to about 89 percent and was decreasing rapidly with time. COD removal efficiency was less affected but did show a decrease in efficiency from near 80 percent to about 72 percent. BOD removal was apparently not affected but, as noted previously, the value of the BOD test for this waste is questionable. It is noteworthy that penta removal efficiency was apparently affected by the shock loading. At a constant loading, the penta removal had averaged 79 percent but, apparently because of the shock loading, this was reduced to virtually zero removal of penta. Whether the decreased removal efficiency was due to a decrease in the rate of oxidation of penta or to the decreased hydraulic detention time was not determined. In order to determine the effects of increased loading and decreased detention time under more constant conditions, two series of loading var- iation were initiated. The flowrate was increased incrementally from 20.8 1pm (5.5 gpm) to a maximum of 41.6 1 pm (11 gpm) for the first series and to a maximum of 49 1 pm (13 gpm) for the second series. The first series of incremental flow variation was conducted during the last two weeks of October and the second series during the first two weeks of November. The activated sludge process was restabilized for a four day period after the shock loading test. On October 15, the flow rate was increased to 26.5 1pm (7 gpm), then 34 1pm (9 gpm) on the 16th, and finally to 41.6 1pm (11 gpm) by the 18th of October. The flowrate was maintained at 41.6 1pm (11 gpm) for about one week. The results of this phase of experi- mentation are shown in Table 19. As the lo-ading was increased, the penta removal efficiency again decreased until virtually no removal was obtained. The phenol removal efficiency decreased slightly but the effluent concentration of phenol never exceeded 3.0 mg/1. Apparently, as the loading was increased, the capacity of the activated sludge in the first aeration basin to oxidize phenols was approached and exceeded. As the loading was increased the concentration of phenols in the first aeration tank increased. This resulted in an increase in the loading on the second tank and some increase in effluent phenol concentration. The increased loading on the second aeration tank produced a rapid buildup of suspended solids which indicated increased biological activity. 58 ------- TABLE 19. RESULTS OF LOADING RATE VARIATION Date 1973 (FIRST 10-15 10-16 10-17 10-18 10-19 10-24 (SECOND 11-2 11-6 Flow Sampling 1pm Point LOADING SERIES) 26.5 Influent #1 Aeration #2 Aeration Effluent 35.1 Influent #1 Aeration #2 Aeration Effluent 35.1 Influent #1 Aeration #2 Aeration Effluent 41.6 Influent #1 Aeration #2 Aeration Effluent 41.6 Influent #1 Aeration #2 Aeration Effluent 41.6 Influent #1 Aeration #2 Aeration Effluent LOADING SERIES) 20.8 Influent #1 Aeration #2 Aeration Effluent 20.8 Influent #1 Aeration #2 Aeration Effluent COD BOD (mg/1) (mg/1) _ - - - _ _ - - - 2117 - - 757 _ _ - - - 755 - - 75 2117 - - 846 1045 - - no 2290 - - 730 Parameter Phenol PCP (mg/1) (mg/1) 75 2.15 2 1 1 1.62 75 3 2 1 80 3 2 1 90 2.15 5 3 2 2.15 75 2.28 5 2 1 1.78 70 6 4 3 90 2.3 3 2 1 2.4 90 3 2 1 Sludge (ml/1) 400 305 - . 430 330 - •» 470 340 - _ 500 365 - mt 500 380 - — 560 440 - _ 600 425 - — 680 490 _ 59 ------- TABLE 19. RESULTS OF LOADING RATE VARIATION Date 1973 (FIRST 11-7 11-8 11-9 11-12 11-13 11-14 Flow Sampling 1pm Point COD LOADING SERIES) (mg/1 ) 26.5 Influent #1 Aeration #2 Aeration Effluent 36.0 Influent #1 Aeration #2 Aeration Effluent 41.6 Influent #1 Aeration #2 Aeration Effluent 49.2 Influent #1 Aeration #2 Aeration Effluent 49.2 Influent 2650 #1 Aeration #2 Aeration Effluent 1040 49.2 Influent #1 Aeration #2 Aeration Effluent Parameter BOD Phenol (mg/1) (mg/1) 90 5 3 2 100 5 2 1 90 7 3 2 80 9 5 2 90 25 15 TO 90 25 20 20 PCP (mg/1) 2.1 _ - 2.1 _ - - - 2.4 - - 2.2 2.7 - _ 3.2 w - _ - 3.1 _ _ 2.7 Sludge (ml/1) _ 700 470 - — 620 470 - .. 690 480 - _ _ _ - _ 525 580 - «• 500 500 - 11-15 0 Effluent 40 (Flowrate Variation Discontinued) 60 ------- The COD removal efficiency, which had decreased during the earlier period of shock loading, continued to decrease during this period also. By October 24, the COD removal efficiency had decreased to about 60 percent. During the same period, however, BOD analyses indicated good BOD removal efficiency. On October 19, with the flowrate at 41.6 1pm (11 gpm), the BOD removal was 93 percent. The second series of loading variation was begun on November 7, following a week-long period of stabilization at the design flowrate. The flowrate was increased to 49 1pm (13 gpm) over a five day period, the results of which are shown in Table 19. The results are quite similar to those obtained in the October series of loading variation. Virtually no penta removal occurred and the COD removal efficiency was reduced to about 60 percent. The buildup of phenol in both aeration basins occurred as before. However, at 49 1pm (13 gpm) the oxidation of phenols decreased very rapidly and was accompanied by sludge bulking in the clarifier. At this rate, detention time in the aeration tanks was 37 hours, the BODrMLSS ratio was approximately 0.12 kg BOD/day/kg MLSS and the COD:MLSS ratio equalled 0.36 kg COD/day/kg MLSS. The penta loading was nearly 1.8 gm/cu m (0.II lb/1000 cu ft) of aeration volume and the phenol:MLSS ratio was 0.01 kg phenol/day/kg MLSS. Because of the fact that the hydraulic capacity of the treatment system was probably exceeded at 49 1pm (13 gpm) and because the de- tention time in the aeration basins was less than 50 percent of the design aeration time, the above loadings probably do not represent the maximum organic loading conditions at which the complete mix activated sludge process could effectively function. It was there- fore decided to reduce the aeration volume by about 50 percent by utilizing only one aeration tank. By then increasing the flowrate or decreasing the MLSS, a comparatively large change In loading could be obtained without hydraulically overloading any unit of the treatment system. Before this phase of the experimentation could be commenced, however, severe winter weather including snow, ice, and subzero tempera- tures set in. At the same time, the immersion heaters which had been placed in the aeration tanks failed. The result was a period from December 8, 1973, through January 17, 1974, during which the treat- ment plant was inoperative due to frozen and broken valves and pipes. During this period the aeration tank contents were aerated to maintain aerobic conditions. Following a period of a few warm days in mid- January, the necessary repairs were completed and plant operations resumed. It should be noted that the activated sludge responded immediately to the reintroduction of feed water and stability was soon apparent. As noted above, it had been decided to utilize only one aeration tank for the purpose of loading variation. Because of the continuing cold weather, it was decided to postpone further loading variation until spring. The main experimentation efforts for the period from January 17, 1974, through March 4, 1974, were directed at observing the effects of post-chlorination of effluent quality. In order to maintain continuity, this period will be discussed out of chronological 61 ------- order so that the results of loading variation can be concluded. Loading variation recommenced on March 5, 197^, following the post-chlorination study. As mentioned previously, this portion of the study was performed using only the first aeration basin which had a volume of about 56,400 liters (14,900 gallons). The initial flowrate was 15 1pm (4 gpm) and the detention time in the aeration tank was 62 hours. The BOD:MLSS ratio was approximately 0.10 kg BOD/day/kg MLSS, the CODrMLSS ratio was 0.27 kg COD/day/kg MLSS, the ratio of phenol to MLSS equalled 0.007 phenol/day/kg MLSS, and the penta loading reached 3.2 gm/cu m (0.2 lb/1000 cu ft) of aeration volume. Using this configuration of treatment units at 15 1pm (4 gpm), a COD reduction of 70 percent, a BOD reduction of 85 percent, and a phenol reduction of 99 percent were obtained. From March 4 through the end of April the flowrate was increased in increments from 15 1pm to 30 1pm (4gpm to 8 gpm). At first, it appeared that a flowrate of 19 to 23 1pm (5 to 6 gpm) was the maximum rate which could be handled without upsetting the biological process. As can be seen in Figure 15, on three different occasions as this flowrate was reached, the phenolic reduction decreased rapidly. The sludge settling characteristics also changed at this loading with the sludge volume index (SVI) increasing from about 100 to over 200. On the third occasion the flowrate was increased beyond this loading range to a maximum of 30 1pm (8 gpm). At this loading, the activated sludge appeared to restabilize considerably and the SVI decreased to approxi- mately 100. The phenol reduction efficiency again returned to 99 percent removal and BOD was removed at about 90 percent efficiency. COD re- moval had decreased markedly at this loading, however, to about 57 percent. Also, the plant operator reported that after about five days at 30 1pm (8 gpm), sludge was beginning to rise in the clarifier. At this point loading variation was suspended. Thus, the maximum loadings achieved with a 31 hour detention time were a CODrMLSS ratio of 0.50 kg COD/day/kg MLSS, a BODrMLSS ratio of 0.18 kg BOD/day/kg MLSS, a phenol:MLSS ratio of 0.013 kg phenol/day/kg MLSS, and a penta loading of 7.3 gm/cu m (0.45 Ib penta/1000 cu ft) of aeration volume. As can be seen, these are relatively high loading rates. The detention time of 31 hours is much less than that reported for penta removal and the penta loading exceeds the maximum loading attempted in previous laboratory studies. PHASE 4 - POST-CHLORINATION STUDIES Post-chlorination studies were begun on February 6, 1974, with the primary objective of determining the effects of chlorine on effluent quality. During this period of the study, the activated sludge process was operated with one aeration basin. The influent flowrate was maintained at 15 1pm (4 gpm) and the MLSS concentration was held constant at about 3500 mg/1 by wasting sludge as necessary. All other operating parameters were maintained constant to minimize as many variables as possible during the post-chlorination phase of the study. 62 ------- CO 70- 63- 60- 83- 30- 45- < Z 40- a" _, O 33- ~Z. LU °- 30- 28- 20 15- 10- 3- INFLUENT PHENOL CONCENTRATION EFFLUENT PHENOL CONCENTRATION, 10 a. o -3 4 -3 I 2 3 4 5 6 7 8 9 10 II 12 13 14 B 16 17 18 19 2021 22 232423 2627 28 2930 I 2 3 4 5 6 7 8 9 10 II 12 13 14 18 16 17 IB 19 20 21 22232425 262728 293031 MARCH, 1974 APRIL.I974 FIGURE 15. Influent and Effluent Phenol Concentration ------- Prior to initiating full-scale post-chlorination, some labora- tory scale studies were performed on the clarified effluent to determine the range of post-chlorination which would be most effective. For this purpose, sodium hypochlorite (clorox) was used at dosages ranging from 15 mg/1 to 500 mg/1 as HOC1. As illustrated in Figure 16, the residual chlorine stabilized within thirty minutes for all dosages and then decreased slowly, if at all. The effect of increasing dosage on COD, penta, and phenol is shown in Table 20. Minimal reduction in COD occurred at even the 500 mg/1 chlorine dosage. The effluent phenol was already below 1 mg/1 and the reduction due to chlorine was not significant. As can be seen in Figure 17, the effect of chlorine on penta was quite significant, producing a maximum apparent reduction of 77 percent at a chlorine dosage of 250 mg/1. The normally brown wastewater was considerably lightened in color with increasing chlorine dose. TABLE 20. LABORATORY POST-CHLORINATION STUDIES C19 Dosage *(mg/l) 15 30 45 250 500 Time (min) 40 40 40 60 60 Penta Phenol (percent reduction) 16 31 38 77 75 — -- -- 25 33 COD -- — — 7 12 In spite of the lack of beneficial results from the laboratory study, full-scale post-chlorination studies were conducted to confirm the laboratory results and to further study the effects of chlorine on penta. Chlorine was injected into the post-chlorination tank at concentrations varying from 7 mg/1 to 155 mg/1 as HOC1. The detention time in the post-chlorination tank at 15 1pm 14 gpm) was about 10 hours. The MLSS concentration was maintained between 3500 and 4000 mg/1. The immersion heaters in the aeration tank limited temperature variations while pH was held constant by lime additions. The dissolved oxygen concentration was maintained at 2 mg/1. As shown in Table 21, there was no reduction in COD even at the highest chlorine dosage. Phenol concentrations in the effluent were reduced by about 50 percent at chlorine residuals exceeding 11.1 mg/1. There were apparent reductions in BOD ranging up to 64 percent. How- ever, the validity of this reduction is questionable considering the retardance of the BOD test and the fact that no COD reduction occurred. The effect of chlorine on penta was either a reduction of penta or a reduction of the concentration of substances which interfered with the analysis for penta. 64 ------- 500- ^400- o> E "5 £300- e c in 200 100 i 15 30 45 60 Time (min) 90 105 120 135 FIGURE 16. Chlorine Residuals with Time ------- 5.0i 4.0- o» E 3.0- 2.0 1.0- 15 IS mg/| Chlorine 30 45 60 i 75 90 K)5 Time (min) 120 FIGURE 17. Effects of Chlorine on Pentachlorophenol Concentrations as Measured bv Safranin Method i 135 ------- CD TABLE 21. EFFECTS OF FULL SCALE POST CHLORINATION Date 2/11/74 2/14/74 2/18/74 2/21/74 2/25/74 2/28/74 3/4/74 Chlorine Feed Ob/day) 0.75 0.75 1.0 3.0 5.0 7.0 10 Chlorine Residual (mg/1) 2 0 3 11 24 32 35 .0 .5 .3 .1 .4 .0 .7 Phenol , , 0) 0.6 0.5 0.4 0.9 1.2 0.8 1.1 mg/1 J2I 0.6 0.5 0.4 0.9 0.6 0.4 0.6 Penta, Jll_ 8.4 7.6 8.1 9.2 9.6 8.2 9.4 mg/1 J21 4.4 5.3 5.2 4.3 3.2 1.4 5.2 COD, HI 595 645 755 700 855 835 805 mg/1 Jii 595 670 760 735 835 860 800 BOD, HI 125 80 95 110 265 100 125 mg/1 Jil 95 75 80 85 95 80 65 (1) Before Chiorination (2) After Chiorination ------- It should be noted that the nutrient levels during this period, as throughout the entire study, were quite elevated due to the previous use of a fire retardant which contained ammonia and phosphorus com- pounds. The presence of large concentrations of ammonium ions in the wastestream may have caused the high residuals of chlorine and con- tributed to the poor reaction of chlorine with the organics in the treated effluent. PHASE 5- PRE-CHLORINATION As has been previously discussed, the primary purpose of pre- chlorination was to reduce penta concentrations to a level that would allow satisfactory biological activity in the activated sludge process. It had been demonstrated during the previous phases of the project that pre-chlorination was not required in order to treat the wastes biologically. The need for pre-chlorination was therefore considered limited. However, before abandoning the concept entirely, it was decided to experiment on a laboratory scale with chlori nation of the raw waste to determine if any measurable benefical effects occurred. Initially, laboratory tests were conducted to determine chlorine persistence. This was considered important due to the high dosages which were expected to be required and because only small chlorine residuals could be allowed to enter the aeration units without damage to the activated sludge. Chlorine doses of approximately 600, 1200, 3400, and 6900 mg/1 were prepared in the laboratory using sodium hypochlorite. Chlorine residual was measured with time over a period of at least 10 hours for each sample. The resulting chlorine residual curves are shown in Figure 18. It can be seen that the primary reaction of chlorine with the raw wastewater occurred within two to four hours and that the decrease in total residual occurred at a much slower rate after this initial period. After 19 hours of reaction time the sample initially treated with 600 mg/1. of chlorine still contained a residual of over 200 mg/1. High initial doses resulted in correspondingly higher total residuals. The 6900 mg/1 initial doses, for instance, produced a residual after 10 hours of over 2600 mg/1. Obviously, if large chlorine doses were required, high chlorine residuals would result and a substantial degree of dechlorina- tion would be required before biological treatment would be possible. .Subsequent laboratory studies were conducted to determine the effects of chlorine on the raw waste at concentrations of chlorine of 500 mg/1 and 1000 mg/1. As illustrated in Figure 19, oxidation of phenols occurred rapidly and completely at chlorine levels of 500 mg/1 and 1000 mg/1. The reaction at pH 8 was somewhat more complete after one hour than the reaction at pH 2. Figure 20 shows penta removal with chlorine doses of 500 mg/1 and 1000 mg/1. The efficiency of removal of penta was 40 percent using 500 mg/1 of chlorine at pH 8, 81 percent using 500 mg/1 of chlorine at pH 2 and about 80 percent using 1000 mg/1 of chlorine at pH 8. 68 ------- 1400-1 CT> VO 1200 rag/1 chlorine dosage A 600 mg/1 chlorine dosage 0 16 18 20 Time After Initial Dose FIGURE 18 (a). Chlorine Persistence (hrs) ------- 7000 6900 mg/1 chlorine dosage 2000- 3400 mg/1 chlorine dosage 1000- 0 6 8 10 12 Time after Initial Dose (hrs) FIGURE 18 (b). Chlorine Persistence 14 16 18 20 ------- 60H 55 50 45- 40- 35 30- x f 25- £ 20- 15- 10 5- 25Omg/l Clodded 500 mg/l CMpH=8 1.0 1.5 2J5 3.0 Tim* (hrs) Figure 19. Effect of Chlorination on Phenolic Concentration of Raw Wastewater with Activated Carbon ------- ro pH=8 mg/1 C12, pH=8 3.0 TIME (hrs) FIGURE 20. Effect of Chiorination on Penta Concentration of Raw Wastewater with Activated Carbon ------- Also shown in Figures 19 and 20 is the effect of adding powdered activated carbon to the raw wastewater. As this was not part of the project objectives, the use of activated carbon was not studied exten- sively. However, the few tests performed indicated that activated carbon at a concentration of 0.5 grams/liter can reduce phenol concen- tration in the raw waste by 84 percent and penta by about 25 percent At a concentration of 2.0 grams/liter, powdered activated carbon removed about 61 percent of the phenols and 98 percent of the penta rem°ved ** H-iU wa? thought that the adsorbed phenol and penta might be more readily oxidized either chemically or biologically while attached to the carbon than when in solution. Therefore, Figures 19 and 20 also show the results of a few experiments in which chlorine was added to a solution of powdered activated carbon and raw wastewater. The effert of the chlorine was apparently to attack the carbon preferentially resulting in the desorption of the phenol and penta molecules! Based on the above results, it was intended that a full-scale pre-chlorination study be performed. A schedule of chlorine doses and dechlorinating agent requirements was prepared and pre-chlorination was begun on May 7, 1974. Due to the high chlorine residuals expected it was decided to initiate pre-chlorination at 50 mg/1 and gradually increase the dosage to a maximum of 500 mg/1. Dechlorination was to be accomplished by the addition of sodium sulfite. Pre-chlorination was continued for one month. Unfortunately, due to several problems, the chlorine dosage never exceeded about 75 mg/1 and no significant reductions in phenol, penta, or COD were obtained. Problems related to pre-chlorination were largely operational. De- chlorination has not been anticipated to be a major problem in the initial design and, consequently, no alternatives other than air stripping were included in the treatment plant. Therefore, control of chlorine residual was accomplished during the study by gravity fed sodium sulfite, and the reliability of this system was poor. Consequently, either due to the chlorine or to excess sodium sulfite entering the aeration basin, the activated sludge process appeared to be suffering rather than benefiting from pre-chlorination. As can be seen by examination of the data contained in the Appendix, on May 28, 1974, phenol reduction efficiency appeared to be decreasing rapidly. Therefore, pre-chlorination was suspended on May 29. DISCUSSION OF RESULTS Based on the data developed during the study, the optimum design and operating parameters for the treatment of the specific wood preserving wastewater studied can be presented. As the characteristics of the waste are dependent upon the wood preserving process from which it comes, the design parameters for this waste may differ significantly from those at any other plant. However, the results and conclusions should allow generalizations for similar wood preserving plants. 73 ------- It was determined early in the study that the wastewater inhibited the BOD test. While this fact precludes the use of the BOD test as a precise method of analysis, it does not eliminate its usefulness as an indicator. The average BOD/COD ratio of 0.35 was found to be rather constant for the raw waste. The result of loading the activated sludge at various rates is summarized for COD in Figure 21. The percent reductions of COD when plotted against the nominal hydraulic detention time produce a linear relation as indicated. Increasing organic loading resulted in a linear decrease in treatment efficiency up to a loading of about 0.35 kg COD/day/dg MLSS, while the decrease in removal efficiency became much less rapid above the loading. BOD and phenol concentration were readily reduced at practically every loading level tested. A BOD reduction of 90 percent and a phenol reduction of 99 percent were obtained. The primary measurable effects of post-chlorination were to marked- ly improve the color of the wastewater and to reduce the penta concen- tration of the wastewater and/or the concentration of substances being measured as penta. Slight reduction of phenol and no reductions of organics were indicated under these operating conditions. At the conclusion of the EPA sponsored program, Koppers Company conducted a further investigation of post-chlorination. Preliminary results indicated that at a pH of 7 to 8 and a flow of 5.5 gpm, penta was reduced from about 5 mg/1 to less than 0.10 mg/1. Pre-chlorination was found to be effective for reducing penta and phenols in the raw waste. The ratio of chlorine to penta required to produce an 80 percent reduction in penta concentration was found to be in excess of 300:1 on a molar basis. In addition, the residual chlorine was found to be high following pre-chlorination,. a condition which was possibly aggravated by the presence of ammonia. The high residual chlorine caused operational problems which were not overcome. Con- sequently, whether pre-chlorination could be beneficial to the activated sludge process was not clearly established. Based on the results of this study, the following are design para- meters for this particular waste: Average COD loading =0.3 kg/day/kg MLSS Maximum COD loading = 0.4 to 0.5 kg/day/kg MLSS Average BOD loading = 0.1 kg/day/kg MLSS Maximum BOD loading = 0.2 kg/day/kg MLSS Average phenol loading =0.01 kg/day/kg MLSS Average penta loading =1.62 gm/day/cu m (0.1 lb/day/1000 cu ft) Maximum penta loading =6.5 gm/day/cu m (0.4 lb/day/1000 cu ft) Average hydraulic detention time = 60 hours Minimum hydraulic detention time = 40 hours 74 ------- Hydraulic Detention Time (hrs.) 10 20 30 40 50 60 70 80 90 100 en 80 . > O) o O O 70 . 60 - 50 0 I 0.3 0.4 COD LOADING RATE, Ibs COD/day/1b MLSS FIGURE 21, COD Removal In The Activated Sludge Process 0.5 ------- At the Carbondale wood preserving facility, the pretreatment system was adequate for recovering pentachlorophenol from the process waste stream prior to biological treatment. A properly designed and operated preservation recovery system in conjunction with equalization is impor- tant for successful operation at the loadings listed above. An activated sludge process designed on the basis of the above should result in the following reduction efficiencies: COD removal efficiency = 70 to 80 percent BOD removal efficiency = 90 percent Phenol removal efficiency = 99 percent Penta removal efficiency = 99 percent 76 ------- SECTION VII REFERENCES 1. American Petroleum Institute. Manual on Disposal of Refinery Wastes, Vol. I. Waste Water Containing Oil (6th Edition).(1959). 2. Industrial Waste Profiles, No. 5 - Petroleum Refining. U.S. Depart- ment of the Interior, Washington, D. C. The Cost of Clean Waste: Vol. III. (1967). 3. Wallace, A. T., G. A. Rohlich, and J. R. Villemonte. The Effect of Inlet Conditions on Oil-Water Separators at SOHIO's Toledo Refinery. In: Proceedings, 20th Purdue Industrial Waste Conference. (1965). 4. 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Oxidation of Phenolic Wastes. 36:9. (1964). 23. American Petroleum Institute. Manual on Disposal of Refinery Wastes.. Vol. I_v Waste Water Containing Oil (6th Edition). (1969). 24. Ingols, R. S., and G. M. Ridenour. The Elimination of Phenolic Tastes by Chloro-Oxidation. Water and Sewage Works. (1948). 25. Ettinger, M. B. and C. C. Ruchhoft. Effect of Stepwise Chlorination on Taste-and-Odor-Producing Intensity of Some Phenolic Compounds. Journal American Water Works Association. 43: (1951). 78 ------- 26. Burttschell, R. G. Chlorine Derivatives of Phenol Causing Taste and Odor. Journal American Water Works Association. 51:2. 1959. 27. Lee, C. F. Kinetics of Reactions Between Chlorine and Phenolic Compounds. Proc. Fourth Rudolfs Research Conf. Rutgers U., New Brunswick, N. J. (1967). 28. Weil, I., and J. C. Morris. J. Am. Chem. Soc. 71. (1949). 29. Vaughn, J. C. Problems in Water Treatment. Journal American Water Works Association 56:5. (1964). 30. Woodward, E. R. Chlorine Dioxide for Water Purification. Journal Pennsylvania Water Works Operators Association 2£k33_. (1956). . 31. Glabisz, 0. Chlorine Dioxide Action on Phenol Wastes. Przem. Chem. 45:211. Chem. Abs. 65:10310. (1966). 32. American Petroleum Institute. Manual on Disposal of Refinery Wastes. Volume on Liquid Wastes, p. 11-3. (1969). 33. Dust, J. Pollution Abatement and Control in the Wood Preserving Industry. Proceedings, Conference on Wood Preserving. Mississippi State College. (November 1970). 34. Cooke, R. and,P. W. Graham. The Biological Purification of the Effluent from a Lurgi Plant Gasifying Biuminous Coals. International Journal of Air and Water Pollution. 9(3):97. (1965). 35. Badger, E. H. M. and M. I. Jackman. Loadings and Efficiencies in the Biological Oxidation of Spent Gas Liquor. Journal and Proceedings of the Institute of Sewage Purification. Vol. (2):159. (1961). 36. Preussner, R. D. and J. Mancini. Extended Aeration Activated Sludge Treatment of Petrochemical Waste at the Houston Plant of Petro-Tex Chemical Corporation. Proceedings, 21st Purdue Industrial Waste Conference, pp. 591-599. (1967JT 37 Coe, R. H. Bench-Scale Method for Treating Waste by Activated Sludge! Petroleum Processing. 7:1128-1132. (1952). 38 Ludberg, J, E. and G. D. Nicks. Phenols and Thiocyanate Removed from Coke Plant Effluent. Ind. Wastes. Vol: 10-13. (November 1969). 39. American Wood Preservers' Association. Report of Wastewater Disposal Committee. Proceedings. American Wood Preservers' Association. 56:201-204. (1960). 40. Nakashio, M. Phenolic Waste Treatment by an Activated-Sludge Process. Hajcko Kosaku. Zassjri. 47:389 and Chem. Abs.. 71(8):236. (1969). -79- ------- 41. Reid, G. W. and R. J. Janson. Pilot Plant Studies on Phenolic Wastes at Tinker Air Force Base. Proceedings, 10th Purdue Industrial l-Jaste Conference, p. 28. (1955). 42. Putilina, N. T. Removal of Phenol from Coke Works Waste Waters. Hygiene and Sanitation, Moscow. Vol. (12):8. (1952), and Water Pol- lution Abs. 28:428. (1955). 43. Meissner, B. Investigations of the Disposal of Phenol -Containing Wastes by Biological Procedures. Wasserwerke-Wass Technology 5:82 and Chem. Abs. 49:14237. (19557: 44. Shukov, A. I. The Treatment of Phenolic Waste Waters. Hygiene and Sanitation, Moscow. 22(5):69. 1957. and Water Pollution Abs. 32:424. (1959T: 45. Kostenbader, P. 0. and J. W. Flacksteiner. Biological Oxidation of Coke Plant Weak Ammonia Liquor. J. WPCF. 41(2):199. (1969). 46. Thompson, W. S. and J. V. Dust. Pollution Control in the Wood Preserving Industry, Part 2. In-Plant Process Changes and Sanita- tion. Forest Products Journal. .22(7). (1972). 47. Kirsh, E. J. and J. E. Etzel. Microbial Decomposition of Penta- chlorophenol. Personal correspondence from E. J. Kirsh to Warren S. Thompson, 1972 and submitted for publication to J. WPCF. 48. Cooper, R. L. and J. R. Catchpole. The Biological Treatment of Coke Oven Effluents. Yearbook, Coke Oven Managers Association. (1967) and Water Pollution Abs. 42T562": (1969). 49. Hsu, C. P., W. F. Yang, and C. N. Weng. Phenolic Industrial Wastes Treatment by a Trickling Filter. K'uo Li Taiwan Ta Hsueh King Cheng Hsueh Kan. Vol. (10):162. 19661 and Chemical Abs. 67:8845. ( 50. Francingues, N. R. Evaluation of a Pilot Study on a Creosote Waste from the Wood Preserving Industry. Proceedings of Mississippi State University short course on Pollution Abatement and Control in the Wood Preserving Industry, p. 165. (1970). 51. Sweets, W. H. , M. K. Hamdy, and H. H. Weiser. Microbiological Studies on the Treatment of Petroleum Refinery Phenolic Wastes. Sewage Ind. Wastes. 26:826-868. (1954). 52. Reid, G. W. and R. W. Libjjy. Phenolic Waste Treatment Studies. Proceedings, 12th Purdue Industrial Waste Conference, pp. 250-258. (1957). 53. Ross, W. K. , and A. A. Sheppard. Biological Oxidation of Petroleum Phenolic Wastewater. Proceedings, 10th Purdue Industrial Waste Conference, pp. 106-119. (1955). 80 ------- 54. Reid, G. W., R. Wortman and R. Walker. Removal of Phenol with Biological Slimes. In: Proceedings, 11th Purdue Industrial Waste Conference, pp. 354-357. (1956). 55. Harlowe, H. W., E. S. Shannon and C. L. Sercu. A Retro-Chemical Waste Treatment System. In: Proceedings, 16th Purdue Industrial Waste Conference, pp. 156-166. (1961). 56. Montes, G. E., D. L. Allen and E. B. Showell. Petro-Chemical Waste Treatment Problems. Sewage Ind. Wastes 28:507-512. (1956). 57. Dickerson, B. W. and W. T. Laffey. Pilot Plant Studies of Phenolic Wastes from Petro-Chemical Operations. In: Proceedings. 13th Purdue Industrial Waste Conference, pp. 780-79T(1958). 58. Davies, R. W., J. A. Biehl and R. M. Smith. Pollution Control and Waste Treatment at an Inland Refinery. In: Proceedings. 21st Purdue Industrial Waste Conference, pp. 126-T31T(1967). 59. Austin, R. H., W. F. Meehan and J. D. Stockham. Biological Oxidation of Oil-Containing Wastewaters. jnd. Eng. Chem. 46:316-318 (1954). . 60. Prather, B. V. and A. F. Gaudy, Jr. Combined Chemical, Physical, and Biological Processes in Refinery Wastewater Purification. In- Proceedings. American Petroleum Institute 44fIII):1Q5-112. (1964). 61. American Petroleum Institute. Manual on Disposal of Refinery Wastes, Vol. I. Waste Water Containing'Oil (6th Edition). Q960). 62. Montes, G. E., D. L. Allen and E. B. Showell. Petro-Chemical Waste Treatment Problems. Sewage Ind. Wastes 28:507-512. (1956). 63. Biczyski, J. and J. Suschka. Investigations on Phenolic Wastes Treatment in an Oxidation Ditch. In: Advances in Water Pollution Research 2:285-289. Pergamon Press, New York.(1967). 64. Skogen, D. B. Treat HPI Wastes With Bugs. Hydrocarbon Processing 46(7):105. (1967). 65. Crane, L. E. An Operational Pollution Control System for Pressure Treating Plant Waste. In: Proceedings, Conference on Pollution Abatement and Control in the Wood Preserving Industry.(W. S. Thompson, Editor). Mississippi Forest Products Laboratory, Mississippi State University, State College, Mississippi. pp. 261-270. (1971). 66. Gaudy, A. F., Jr., R. Scudder, M. M. Neeley and J. J. Perot. Studies on the Treatment of Wood Preserving Wastes. Paper presented at 55th National Meeting, Amer. Insti. Chem. Eng., Houston, Texas. (1965). 81 ------- 67. Gaudy, A. F., Jr. The Role of Oxidation Ponds in a Wood Treating Plant Waste Abatement Program. In: Proceedings, Conference on Pollu- tion Abatement and Control jiji the Wood Preserving Industry. (W. S. Thompson, Editor).Mississippi Forest Products Laboratory, Mississippi State Univ., State College, Mississippi, pp. 150-164. (1971). 68. Fisher, C. W. Koppers1 Experience Regarding Irrigation of Indus- trial Effluent Waters and Especially Wood Treating Plant Effluents. In: Proceedings, Conference on Pollution Abatement and Control in the Wood Preserving Industry.(W. S. Thompson, Editor).Mississippi Forest Products Laboratory, Mississippi State University, State College, Mississippi, pp. 232-248. (1971). 69. Gloyna, E. F. and J. F. Malina, Jr. Petrochemical Waste Effects on Water, Part 2. Physiological Characteristics. Industrial Water and Wastes. (November-December, 1962). 70. Gould, M. and J. Taylor. Temporary Water Clarification System. Chem. Eng. Progress 65(12). (1969). 71. Kirsch, Edwin J. and J. E. Etzel. Microbial Decomposition of PCP. JWPCF 45(2). (February 1973). 72. American Public Health Association Standard Methods. American Public Health Assoc., Inc., New York, New York. 82 ------- SECTION VIII GLOSSARY Activated Sludge - Sludge floe produced in raw or settled wastewater by the growth of zoogleal bacteria and other organisms in the presence of dissolved oxygen and accumulated in sufficient concentration by re- turning floe previously formed. Aerated Lagoon - A natural or artificial wastewater treatment pond in which mechanical or diffused-air aeration is used to supplement the oxygen supply. Alum - A common name in the water and wastewater treatment field for- commercial -grade aluminum sulfate. Bentonite - An absorptive and colloidal clay used especially as a filler (as in paper) or carrier (as of drugs). BOD - Biological Oxygen Demand is a measure of biological decomposition oTbrganic matter in a water sample. It is determined by measuring the oxygen required by microorganisms to oxidize the organic contaminants of a water sample under standard laboratory conditions. The standard conditions include incubation for five days at 20°C. COD - Chemical Oxygen Demand. Its determination provides a measure of thT oxygen demand equivalent to that portion of matter in a sample which is susceptible to oxidation by a strong chemical oxidant. Creosote - A complex mixture of organic materials obtained as a by-product from coking and petroleum refining operations that is used as a wood pre- servative. Cresol - Any of three poisonous colorless crystalline or liquid isomeric phenols Emulsion - A heterogeneous liquid mixture of two or more liquids not normally dissolved in one another, but held in suspension one in the other by forceful agitation or by emulsifiers which modify the surface tension of the droplets to prevent coalescence. Flocculation - In water and wastewater treatment, the agglomeration of colloidal and finely divided suspended matter after coagulation by gentle stirring by either mechanical or hydraulic means. In biological wastewater treatment where coagulation is not used, agglomeration may be accomplished biologically. Lime - Any of a family of chemicals consisting essentially of calcium fiydroxide made from limestone (calcite) which is composed almost wholly of calcium carbonate or a mixture of calcium and magnesium carbonate. 83 ------- Mixed Liquor - A mixture of activated sludge and organic matter under going activated sludge treatment in the aeration tank. Pentachlorophenol - A crystalline compound CgClgOH used as a wood preservative, fungicide and disinfectant. Phenol - The simplest aromatic alcohol. Polyelectrolyte - A nonmetallic electric conductor of high molecular weight in which current is carried by the movement of ions. Quinone - Either of two isomeric cyclic crystalline compounds that are di-keto derivatives of dihydro-benzene. Sludge Volume Index (SVI) - It is the volume in milliliters occupied by 1 gm of activated sludge after settling of the aerated liquid for thirty minutes. Thiocyanate - A salt or ester of thiocyahic acid, a colorless unstable liquid acid (HSCN) of strong odor. Trickling Filter - A filter consisting of an artificial bed of coarse material, such as broken stone, clinkers, slate, slats, brush, or plastic materials, over which wastewater is distributed or applied in drops, films, or spray from troughs, drippers, moving distributors, of fixed nozzles, and through which it trickles to the underdrains, giving oppor- tunity for the formation of zoogleal slimes which clarify and oxidize the wastewater. 84 ------- SECTION IX APPENDIX OPERATIONS LOG The treatment facilities at Carbondale were placed in operation on July 26, 1973 and the testing program was terminated on May 31, 1974. Table A presents a summary of key data collected during the study. Following is a condensation of the daily log maintained by the treatment plant operators: August 1973 The activated sludge plant was installed and filled with water from the emergency lagoon. Horse manure was used as a seed and aeration began on July 26. The reason for using water from the emergency lagoon initially was that it had relatively low concentrations of phenol, penta, and boron and its pH was near neutrality. Subsequently, wastewater from Lagoon No. 1 was gradually added. Three thousand gallons of water from Lagoon No. 1 were added on July 31. Until August 20 the influent to the activated sludge system consisted of a mixture of waters from the emergency lagoon and Lagoon No. 1, but on that date the emergency lagoon pump broke down and problems de- veloped with the pump on Lagoon No. 1. Although both pumps were repaired on August 23, it was decided to continue use of only water from Lagoon No. 1, and to increase the flow by one gallon per minute each day until a flow of 6 gpm was obtained. It was observed that almost no suspended solids were building up in the aeration tanks. On August 13 floating sludge was observed in the clarifier. Although sludge was returned to aeration at maximum capacity, the problem continued. On August 28 it was discovered that a pin had sheared in the clarifier paddle assembly preventing aeration of the paddles. The clarifier was emptied into the aeration tank and repairs were made. Considerable amounts of protozoa were observed from initial start- up until August 21 when the numbers began to drop drastically. Small amounts of lime were added to Aeration Tank No. 1 to increase the pH, and the protozoa count increased. Due to lack of power at the on-site laboratory, penta analyses were not begun until August 21. September 1973 The month of September was intended as a sludge build-up period. Settleable solids increased from 35 ml/1 at the beginning of September to 180 ml/1 at the end of the month. By the end of the month the MLSS was about 2000 mg/1. 85 ------- The water level in Lagoon No. 1 was getting low enough that the pump began to pick up debris from the bottom, so water was added to Lagoon No. 1 from Lagoon No. 3. This temporarily lowered the concentration of penta and phenol entering the activated sludge system, but as raw wastes continued to be added to Lagoon No. 1, these concentrations began to rise. October 1973 On October 8, by which time the MLSS of both aeration tanks averaged about 2500 mg/1 and settleable solids about 270 ml/1, the feed rate was set at 11 gpm and maintained at that rate through October 10. From October 11 through October 14 the feed was reduced to 5.5 gpm while the aeration tanks were being sprayed with an insulation material and painted. As indicated in Table A, the flow rate of 11 gpm resulted in a reduced efficiency as phenol removal. So on October 15, when both aeration tanks were back in operation it was decided to raise the feed rate gradually while allowing the system to adjust and reduce phenol levels prior to each increase. It took four days to again achieve a flow of 11 gpm. The rate of 11 gpm was maintained from October 18 through October 25 with only a slight loss in phenol removal efficiency. On October 26 the flow was reduced to 5.5 gpm to allow stabilization in preparation for tripling the feed rate. As can be seen in Table A, the pH of the influent to the activated sludge system was consistently below 5.0. Prior to the feed increase on October 8, only periodic additions of small amounts of lime were necessary to maintain a pH in the aeration tank at above 6.0. How- ever, after the flow was increased on October 8, considerably larger lime dosages were necessary nearly every day. November 1973 On November 7 the feed rate was increased from 5.5 to 7 gpm and then gradually increased to 13 gpm by November 12. This rate was maintained for three days, at which time drastically reduced phenol removal necessitated a feed reduction. Six gallons per minute were fed until the holiday weekend of November 22 during which time the flow was cut off and the air supply decreased. The reason for shutting off the flow was that many wood preserving plants do not have the lagoon capacity that the Carbondale facility does and no flow on a long weekend would be normal. Also, in an effort to conserve electricity (the winter of 1973 found the United States in an "Energy Crisis"), the metabolism of the sludge was reduced by timing the air pumps to run for one hour and be off for five hours. Large quantities of lime were necessary to maintain the pH in the aeration basins near neutrality. This was especially true during the period of high feed rate. ------- Protozoa were easily visible until the system upset of November. 15. On November 16 horse manure was added to replace protozoa. December 1973 The stabilization period of the last week in November was maintain- ed into December. On December 3 heaters were installed in the aeration tanks and these were expected to maintain a water temperature of at least 20°C. On December 3 the water temperature was 15°C. By the next day the heaters had increased it to 17°C; however, the temperature then dropped until by December 7 it was at 11°C. During the weekend of December 8 and 9 the flow was cut off and the air pumps were operated for one hour of each six hours. This did not allow adequate water circulation over the immersion heaters; they' developed a sludge layer and burned out. The lack of circulation also led to freezing of several lines and both pumps in Lagoon No. 1. There was a thin layer of ice on all tanks. By December 13 the system had thawed enough that repairs could be begun. More cold weather appeared on December 19 and from that date until December 25 there was at least a four inch layer of ice on all tanks. All operations were suspended. The plant was back in operation on December 26. Then, on December 29, a line became clogged with ice and the system became frozen again. January 1974 It was decided that for the remainder of the study only Aeration Tank No. 1 would be used in order to allow better operational control. On January 8 new heaters were installed in the aeration tank by chopping through five inches of ice. By January 10 the aeration tank had thawed, but the external valves and lines were still frozen. On January 17 the system was placed in operation with a flow of 1.5 gpm. Also on January 17, heaters were installed in the pre-chlorination unit. The temperature in the aeration basin gradually increased but did not rise above 20°C until January 21. The flow was gradually increased until it reached 4 gpm on January 28 (it would be maintained at this rate until March 11). On January 23 a program of wasting small amounts of sludge to the digester was initiated. The MLSS at this time was 4650 mg/1, and it was intended to eventually reduce it to 3500 mg/1. February 1974 By the beginning of February the activated sludge system was operated as designed and as soon as the ,MLSS became stationary it was -87- ------- planned to begin post-chlorination. By February 7 the MLSS was below 3800 mg/1 and post-chlorination was initiated at 7 pounds of chlorine per day. This resulted in a chlorine residual of 35 mg/1. It was decided to determine what chlorine feed rate would yield a residual of near 1 mg/1. February 10 through 14 results on Table B show a feed of 0.75 ppd would achieve a residual of about 1 mg/1. It was also intended to increase the chlorine feed gradually to a maximum of 10 ppd to determine effects of BOD, COD, penta, and phenols. This was done from February 15 through March 4. From February 22 through March 4 the pH of the post-chlorinated water began to drop drastically as the chlorine feed approached 10 ppd. March and April 1974 The objective during March and April was to determine the effects of increased flow rates while maintaining other factors constant. Throughout the two-month period it was necessary to add large amounts of lime (12 to 16 pounds every second or third day) in order to control pH in the aeration basin. On March 7 the line between the aeration basin and the clarifier became clogged. This caused the aeration basin to overflow and lose solids. Beginning March 9 flow rates were increased until March 17. On March 16 the sludge return line became clogged and large amounts of sludge had to be wasted in order to unclog the line. Horse manure was added to the aeration basin on March 13 to increase the protozoa count. Beginning on March 19 the flow rate was again increased until it reached 6.5 gpm on March 22. At this point the phenol concentration in the effluent had risen to such a high level that the flow was reduced to 3 gpm to allow system stabilization. Sludge had to be wasted almost daily in order to maintain a MLSS of approximately 3500 mg/1. On March 21 phenols and penta concentrations were observed to be low in the digester. It was decided to incorporate a sludge contact chamber. On March 26 all return sludge was pumped to the digester for two hours detention before being returned to the aeration basin. Using the contact tank, the flow was gradually increased until April 8 when the submersible pumps went out. The system was immediately converted back to straight activated sludge. The feed rate was continually increased, despite increased phenol concentrations in the effluent, until April 29 when sludge began to float in the clarifier. On April 11 the penta oil separation system malfunctioned and penta was spilled into Lagoon No. 1. On April 15 the spill began to appear in the treatment system. 88 ------- May 1974 The primary objective during May was to determine the effects and operating parameters of pre-chlorination. The flow rate was set at 6 gprru It was intended to maintain a MLSS of 3500 mg/1, but, as shown in Table A, the MLSS varied from 2790 to 4320 mg/1. Pre-chlorination began at 50 mg/1 and was scheduled to be increased to 500 mg/1 during the month. Sodium sulfite was used for de-chlorination prior to aeration. Sodium hydroxide was used to maintain a pH of 7 to 8 in the aeration basin. Pre-chlorination was initiated on May 7 at 50 mg/1. No residual resulted. On May 9 the chlorine feed rate was increased to 75 mg/1 and a residual of 1 to 2 mg/1 resulted. Due to the fact that extreme difficulties were encountered in controlling the sodium sulfite addition by the gravity feed system, 'it was decided to install a feed pump. The pre-chlorination feed rate was maintained at 75 mg/1 until the pump could be installed. The feed pump was received on May 22 and prepared for installation. However, on May 28 it became apparent from increasing phenol levels in the effluent that the activated sludge system was breaking down. The pre-chlorination schedule was discontinued. 89 ------- TABLE A. 10 O DAILY LOG SUMMARY DO in Phenol Penta BOD COD PO* NH4 SS Aeration MLSS Flow (mg/1) (mg/1) (mg/1) (mg/1) (mg/1) (mg/1) (mg/1) (mg/1) (mg/1) pH 7/26/73 7/31/73 8/2/73 8/31/73 8/4/73 8/5/73 8/6/73 8/7/73 8/8/73 a/9/73 8/10/73 8/13/73 8/14/73 8/15/73 8/16/73 8/17/73 8/21/73 8/22/73 8/23/73 8/24/73 8/25/73 8/26/73 8/27/73 8/28/73 8/30/73 8/31/73 9/4/73 9/5/73 9/6/73 9/7/73 Aeration Basin Wastewater Added Rising Sludge Pump Problems Pumps Corrected Lime Added Clarifier Paddles Corrected Lime Added AHfl-Lf 5 5 5 5 5 5 5 5 5 5 5 5 4.5 2 2 3 4 5 5 6 6 6 6 6 6 6 6 5.9 5.8 5.8 5.8 5.5 5.4 5.5 5.5 5.4 5.5 5.5 5.4 5.5 5.5 5.4 - - 5.2 5.3 5.0 5.1 5.0 4.9 3.9 5.0 6.1 6.4 6.3 6.4 6.4 6.5 6.5 6.5 6.5 6.5 6.5 6.2 6.1 6.2 6.2 6.2 6.2 6.5 6.3 6.6 6.6 6.5 6.7 6.6 6.4 0.4 12 15 27 30 65 65 65 75 65 70 70 70 70 70 70 - - 80 85 95 90 90 95 95 0.6 <1 <1 <1 <1 1 1.4 1.6 1.5 1.5 2.0 2.0 1.5 3.4 0.6 1,5 3.4 0.3 2.0 2.3 0.86 1.0 2.6 0.3 2.0 3.0 2.0 2.0 2.0 1 2 2.2 0.6 1 2.7 0.5 2 40 1 260 350 - 440 - 67 1820 470 1960 440 - 380 - 67 ------- DATE REMARKS TABLE A. DAILY LOG SUMMARY DO in pH Phenol Penta BOD COD P04 NH4 SS Aeration MLSS How (mg/1) (mg/1) (mg/1) (mg/1) (mg/l) (mg/1) {mg/1) (mg/1) (mg/1) (gpm) Inf. Eff. Inf. Eff. Inf. Eff. Inf. Eff. Inf. Eff. Inf. Eff. Inf. Eff. Inf. Eff. #1 #2 #1 #2 9/10/73 9/12/73 9/13/73 9/14/73 9/17/73 9/18/73 9/19/73 9/20/73 9/21/73 9/24/73 9/25/73 9/27/73 9/28/73 10/1/73 10/2/73 10/3/73 10/4/73 10/5/73 10/8/73 10/9/73 10/10/73 10/11/73 10/12/73 10/15/73 10/16/73 10/17/73 10/18/73 10/19/73 Added Lime Added Line Tank Maintenance Added Lime Added Lime Added Lime (10/19-10/22) 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 11 11 11 5.5 5.5 7 9 9 11 11 5.2 5.5 5.1 5.0 5.0 5.0 5.0 4.9 4.9 4.9 4.9 4.9 4.8 4.7 4.7 4.7 4.7 4.5 4.7 4.7 4.6 4.7 4.7 4.8 4.8 4.8 4.8 4.7 6.6 6.5 6.5 6.5 6.5 6.6 6.4 6.4 6.3 6.2 6.4 6.2 6.1 6.0 6.2 6.2 6.2 6.2 6.0 6.1 6.3 6.2 6.3 6.2 6.4 6.2 6.1 6.2 70 70 70 95 90 90 90 90 90 90 90 100 100 100 110 100 100 100 110 no 120 90 100 75 75 80 90 75 <1 <1 1 1 <1 1 1 < 2 2 1 1 1 1 3 9 10 7 1 1 1 2 1 1 1 1 1 1 1 1 1 1 1 1 1 2 2 2 2 .7 .8 .6 .5 .5 .2 .7 .53 .73 .82 .35 .62 .36 .15 .15 .28 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. 1. 1. 1. 2. 1. 6 1550 400 3 - 430 - 57 1 1700 400 - 400 - 67 3 2 3 1925 375 5 - 360 - 55 64 - 106 2272 612 64 - 350 - 50 97 57 2647 708 32 415 40 62 62 2117 757 15 78 755 75 - 340 2426 1751 4050 3690 3650 2640 ------- TABLE A. DAILY LOG SUWARY 10 ro DATE 10/23/73 10/24/73 1 0/25/73 10/26/73 10/29/73 10/30/73 10/31/73 11/1/73 11/2/73 11/5/73 11/6/73 11/7/73 11/8/73 11/9/73 11/12/73 11/13/73 11/14/73 11/18/73 11/19/73 11/20/73 11/21/73 11/26/73 11/27/73 11/28/73 11/29/73 REMARKS Added Lime Added Lime Added Lime Began Regular Lime Addition Poor Sludge Separation No Feed (11/15,11/16) No Feed (11/22-11/25) Flow (gpm) 11 11 11 5.5 5. 5. 5. 5. 5. 5. 5. 7 9. 11 13 13 13 6 6 6 6 6 6 6 6 5 5 5 5 5 5 5 5 pH Inf. Eff. 4.8 4.8 4.8 4.9 4.8 4.8 4.8 4.8 4.8 4.8 4.8 4.8 4.9 4.7 4.7 4.8 4.7 - 4.7 4.7 4.7 4.8 4.8 4.8 6.4 6.3 6.4 6.4 6.4 6.4 6.7 6.7 6.7 6.6 6.6 6.6 6.6 6.6 6.6 6.8 6.7 6.9 6.9 6.7 6.8 6.8 6.9 6.8 Phenol ("9/1 ) Inf. Eff. 75 70 70 70 90 80 90 80 90 90 90 90 100 90 80 90 90 - 90 90 90 70 3 3 2 3 2 1 1 1 1 1 1 2 1 2 2 10 20- 4 4 2 1 2 Penta BOD COD P04 NH4 (mg/1) (mg/1) (mg/1) (mg/1) (mg/l) Inf. Eff. Inf. Eff. Inf. Eff. Inf. Eff. Inf. Eff. 1.68 2.22 1.93 2 2 2 2 2 2 3 4 4 4 .30 .3 .1 .1 .4 .7 .1 .4 .4 .6 2.02 2117 846 - 460 - 45 2.56 860 63 2.15 3.13 2217 803 - 320 - 55 2.4 1045 110 2.3 2290 730 2.1 - 300 - 52 2.2 3.3 2650 1040 2.7 3.8 2910 1090 3.5 - 260 - 40 - 260 - 45 4.3 2240 1030 DO in SS Aeration MLSS (mg/1) (mg/1) (mg/1) Inf. Eff. #1 #2 #1 #2 4280 3500 2.5 7.8 3.0 9.5 4940 3800 2C A C .5 4.5 1115 1 . O 1 . J 5250 '4930 5340 4970 1.0 3.5 120 270 1.5 1.5 2.0 6.0 5110 4660 2.3 7.5 ------- TABLE A DAILY LOG SUMMARY U3 DATE REMARKS 11/30/73 12/3/73 Heaters Installed 12/4/73 12/5/73 12/6/73 12/7/73 12/10/73 Lagoon Pump Frozen 12/12/73 12/13/73 12/14/73 #1 Tank Repair Begun 12/17/73 12/18/73 12/19/73 12/26/73 12/27/73 12/28/73 Both Tanks in Operation 1/15/74 No Row 1/18/74 Flow Into #1 Only 1/21/74 1/22/74 Increased Air 1/23/74 1/24/74 1/25/74 1/28/74 Air Pump Break Down 1/29/74 Flow (gpm) 6 6 6 6 6 6 0 6 6 3 3 3 3 3 3 1.5 0 1.5 2.5 3 3 3 3 4 4 pH Inf. Eff. 4.8 4.7 4.7 4.9 4.8 4.8 4.8 4.8 4.7 4.8 4.7 4.8 4.8 4.9 4.8 4.8 4.8 4.9 4.8 4.9 4.8 4.8 4.9 6.9 6.9 7.0 7.1 6.9 6.9 7.2 7.0 6.9 6.7 6.9 6.9 7.0 7.1 6.9 7.4 7.1 7.2 7.0 7.1 6.7 6.6 Phenol (mg/l ) Inf. Eff. 54 55 56 54 55 55 56 35 44 42 38 43 43 44 0.7 0.5 0.4 0.9 0.7 5.1 13 1.5 0.7 0.4 0.1 0.2 0.1 0.4 Penta (mg/l) Inf. Eff. 4.1 4.5 4.1 3.8 4.9 4.2 4.1 3.7 3.4 4.0 4.2 3.0 3.6 3.0 4.1 4.9 4.0 4.3 5.9 4.8 5.2 4.5 .4.9 4.6 5.0 4.3 4.2 3.8 BOD COD P04 (mg/l) (mg/l) (mg/l) Inf. Eff. Inf. Eff. Inf. Eff. 780 100 2100 2110 985 103 2040 2150 1065 125 2180 2170 821 - 2110 1620 540 85 1610 1730 1730 695 100 1730 790 135 1640 1000 220 200 940 200 200 820 360 300 260 880 910 240 240 1060 990 690 690 200 200 690 200 200 610 710 260 200 DO in NH4 SS Aeration MLSS (mg/l) (mg/l) (rag/1) (mg/l) Inf. Eff. Inf. Eff. #1 #2 #1 12 110 200 2.2 2.0 60 40 90 200 1.5 2.2 60 42 100 160 2.9 2.8 3.2 60 35 60 120 5.0 _ . 65 55 100 160 3.0 2.0 55 55 80 110 0.5 2.2 60 45 100 150 1.6 2.0 0.5 55 45 130 170 0.5 9.0 5180 8.5 6.5 5000 7.5 5.5 5040 7.8 5.0 7.5 5190 5.8 7.5 9.5 3570 4900 3810 _ j, - 4650 - 4620 4610 4090 3940 4420 4540 4860 4080 4880 _ — ------- TABLE A. DAILY LOG SUMMARY DATE REMARKS 1/30/74 1/31/74 2/1/74 2/4/74 2/6/74 2/8/74 2/11/74 2/12/74 2/13/74 2/14/74 2/15/74 2/18/74 2/19/74 2/20/74 2/21/74 2/22/74 2/25/74 2/26/74 2/27/74 2/28/74 3/1/74 3/4/74 3/5/74 3/6/74 3/7/74 3/8/74 3/11/74 3/12/74 3/13/74 Added Horse Manure 3/14/74 Flow 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 5 5 5 5 Inf. 4.8 4.8 4.8 4.8 - 4.9 4.8 4.8 4.8 4.8 4.8 4.9 4.8 4.9 4.9 4.9 5.3 5.0 5.0 5.1 5.0 5.1 5.1 5.0 4.7 4.9 4.7 4.7 PH Eff. 6.5 6.8 6.7 6.8 5.8 6.4 6.8 6.6 6.6 6.5 6.6 6.0 5.7 6.2 5.6 4.2 4.7 3.7 4.6 3.3 3.0 6.9 6.9 6.9 6.5 6.7 6.8 6.7 Phenol (mg/1) Inf. Eff. 52 0.2 56 0.4 62 0.6 59 0.5 58 0.4 62 0.9 64 0.6 63 0.4 , 70 0.6 66 0.2 60 0.6 Inf 3.5 4.0 5.1 3.9 5.2 7.4 Penta (mg/1) . Eff. 4.9 5.7 4.4 5.3 5.2 4.3 6.0 3.2 3.2 5.4 7.8 8.6 7.5 1.4 5.2 7.4 8.6 8.1 BOD COD P0a (mg/1) (mg/1) (mg/1) Inf. Eff. Inf. Eff. Inf. Eff. 515 1040 520 465 565 630 730 1070 740 920 860 770 1015 85 1830 570 220 2110 605 55 95 2340 595 220 180 75 2450 570 80 2390 760 200 160 85 2420 735 95 2500 835 220 180 80 2630 860 65 2800 800 200 200 85 2965 722 95 2620 855 180 180 135 2715 985 DO In NHd SS Aeration (mg/1) (mg/1) (mg/1) Inf. Eff. Inf. Eff. #1 #2 90 55 30 115 no 60 40 175 160 70 50 140 160 65 40 850 60 25 175 1.0 1.0 100 1.0 - 1.0 - 2.5 - 2.4 - 3.0 100 2.1 - 2.0 - 1.5 - 90 1.5 0.5 - 110 1.9 - 2.5 - 0.4 - 115 0.5 - 3.5 - 110 2.5 - 1.5 - 2.2 - 135 0.5 - 0.5 - 700 1.7 - 2.2 - 1.0 - 2.0 - 1.5 - 165 1.7 - 1.2 - 1.2 - MLSS (mg/D #1 #2 4340 - 4125 - 3375 - 3860 - 3620 - 3880 - 3780 - 3660 - 3760 - 3390 - 3610 - 3765 - 3585 - 4155 - 3930 - 2750 - 3445 - 4290 - 4395 - 3775 - ------- TABLE A. DAILY LOG SUfWARY in DATE REMARKS DO in pH Phenol Penta BOD COD P04 NH4 SS Aeration MLSS Flow (mg/1) (rag/1) (mg/1) (mg/1) (mg/1) (mg/1) (mg/1) (mg/1) (mg/1) (gpro) Inf. Eff. Inf. Eff. Inf. Eff. Inf. Eff. Inf. Eff. Inf. Eff. Inf. Eff. Inf. Eff. 11 K 11 #2 3/15/74 3/16/74 3/17/74 3/18/74 3/19/74 3/20/74 3/21/74 3/22/74 3/25/74 3/26/74 3/27/74 3/28/74 3/29/74 4/1/74 4/2/74 4/3/74 4/4/74 4/5/74 4/8/74 4/9/74 4/10/74 4/11/74 4/12/74 4/15/74 Sludge Return Line Clogged Started Returning Sludge To Contact Tank For 2 hr Then to 11 Tank Stop Use of Contact Tank 5 5.5 5.5 4 5 5.5 6 6.5 4 4 4 4 4 4 5 5 5 5.5 5.5 5.5 6 6 6 6 4.7 4.7 .8 .7 .8 .8 .8 4.9 4.8 4.8 4.8 4.9 4.8 4.8 4.8 4.8 4.7 4.7 4.7 4.7 4.7 6.9 6.9 6.9 6.9 6.7 6.9 6.8 6.7 6.8 6.8 6.8 6.8 6.8 6.8 6.8 6.6 6.8 6.7 6.7 6.6 6.8 65 59 60 63 60 64 60 58 59 0.5 1.2 5.0 0.3 0.2 0.2 0.2 9.5 0.3 7.2 8.1 7.4 6.6 6.1 6.4 6.7 7.1 8.6 9.1 9.9 7.0 6.2 6.5 6.8 6.4 7.2 10.4 830 910 875 750 865 945 995 845 100 115 95 120 100 115 135 120 2245 2455 2400 2365 2375 2285 2580 2640 700 160 160 725 720 710 160 140 . 650 125 125 790 1070 180 65 160 100 50 35 80 120 145 145 140 135 60 40 105 155 65 60 110 135 320 155 1.0 2.7 3.0 1.4 3.0 3.5 3.0 4.0 4.0 2.8 2.2 3.5 2.5 2.5 3.0 3.5 4.0 4.0 2.7 2.0 3.0 - 3805 - 1645 - 3530 _ - 3605 - - 3350 - 3785 - 2920 _ - 3315 - 3040 - - 3320 - 2910 - 3355 - 3780 - 4220 - 3980 - 4385 - 4880 - _ . _ _ _ _ _ - _ - _ . _ _ - ------- TABLE A. DAILY LOG SUWARY 10 DATE 4/16/74 4/17/74 4/22/74 4/23/74 4/24/74 4/25/74 4/26/74 4/29/74- 4/30/74 5/1/74 5/2/74 5/3/74 5/6/74 5/7/74 5/8/74 5/9/74 5/10/74 5/11/74 5/12/74 5/13/74 5/15/74 5/16/74 5/17/74 5/20/74 5/21/74 5/22/74 5/23/74 5/24/74 5/28/74 5/29/74 5/30/74 5/31/74 REMARKS Rising Sludge Started Pre- Chlori nation Excessive Foam Began NaOH for pH Control Stop Free Chi ori nation Flow (gpm) 6.5 6.5 7.5 7.5 8 8 8 8 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 5 6 6 6 0 0 pH Inf. Eff. 4.9 4.7 4.7 4.8 4.7 4.7 4.7 4.8 4.7 4.8 4.7 4.7 4.9 4.7 4.7 4.7 4.7 4.7 6.6 6.7 6.9 6.6 6.8 6.7 6.8 7.0 6.8 6.8 7.2 7.0 7.2 7.2 7.2 6.9 7.0 6.8 Phenol (mg/1) Inf. Eff. 56 65 64 68 70 72 80 74 82 74 2.3 0.5 0.4 0.4 0.4 0.5 0.5 0.2 0.2 8 DO in Penta BOD COD P04 NH. SS Aeration MLSS (mg/1) (mg/1) (rng/1) (mg/1) (mg/1) (mg/1 ) (mg/1) (mg/1) Inf. Eff. Inf. Eff. Inf. Eff. Inf. Eff. Inf. Eff. Inf. Eff. #1 #2 #1 #2 15.8 11.2 7.6 8.9 8.9 8.0 9.2 2.8 6.6 5.4 17.2 22.4 15.2 19.2 14.5 7.2 12.0 9.6 6.2 5.0 885 100 2595 935 95 2465 2565 835 102 2465 680 90 2580 740 85 2320 660 85 2225 720 90 2070 695 85 2105 120 120 1155 1100 120 120 930 780 895 970 685 740 655 225 210 3.5 5.0 3.5 60 40 1.2 1.3 180 90 0.5 3.0 70 40 150 280 1.0 1.5 0.7 130 110 2.0 2.0 1.8 130 140 1.0 1.0 135 210 1.0 1.7 2.1 3.0 1.5 1.5 1.5 3.0 0.8 0.6 - 5070 - - 3710 - 4225 - - 4050 - - - 4260 - - 3285 - - - 3515 - - 3715 - - 3865 - - - 4150 - 4180 - - 4320 - - 3725 - - - 3495 3410 2790 2940 3470 3670 3630 3040 ------- TABLE B, POST-CHLORINATION Date 2/7/74 2/8/74 2/9/74 2/10/74 2/11/74 2/12/74 2/13/74 2/14/74 2/15/74 2/18/74 2/19/74 2/20/74 2/21/74 2/22/74 2/25/74 2/26/74 2/27/74 2/28/74 3/1/74 3/4/74 cr OJ ? Feed 3/day) 7 0.5 1.5 1 0.75 0.75 0.75 0.75 1 1 3 3 3 5 5 7 7 7 10 10 7 1 g Residual (mg/1) 35 0 4.4 6.6 2.0 1 1 0.5 3.3 2.4 11.6 13.9 11.1 22.4 24.4 33.4 35.2 32.0 47,4 35.7 97 ------- TECHNICAL REPORT DATA (Please read Instructions on the reverse before completing) 1. REPORT NO. EPA-600/2-76-231 3. RECIPIENT'S ACCESSION-NO. 4. TITLE AND SUBTITLE Treating Wood Preserving Plant Wastewater by Chemical and Biological Methods 5. REPORT DATE September 1976 (Issue Date) 6. PERFORMING ORGANIZATION CODE 7. AUTHOR(S) John T. White, T. A. Bursztynsky, John D, and Richard H. Jones 8. PERFORMING ORGANIZATION REPORT NO, Crane 9. PERFORMING ORGANIZATION NAME AND ADDRESS Koppers Company Forest Products Division 10. PROGRAM ELEMENT NO. 1BB610 11. CONTRACT/GRANT NO. 12100 HIG 12. SPONSORING AGENCY NAME AND ADDRESS Industrial Environmental Research Laboratory - Cin., OH Office of Research and Development U.S. Environmental Protection Agency Cincinnati, Ohio 45268 13. TYPE OF REPORT AND PERIOD COVERED Final 14. SPONSORING AGENCY CODE EPA/600/12 15. SUPPLEMENTARY NOTES Performed for the Koppers Company by ENVIRONMENTAL SCIENCE AND ENGINEERING, INC, P. 0. Box 13454, University Station, Gainesville, Florida 32604 16. ABSTRACT A completely mixed activated sludge system was designed for a wood pre- serving plant with an average daily wastewater flow of 27,000 I/day (7,150 gal/day), a BOD concentration of 1,100 mg/1, and a phenol concen- tration of 120 mg/1. Included in the design were capabilities for pre- and post-chlorination. The activated sludge system alone was capable of re- moving 90 percent BOD, 75 percent COD, 99 percent phenol, and 76 percent pentachlorophenol. Post chlorination dosages of over 50 mg/1 resulted in 50 and 52 percent reductions of phenol and pentachlorophenol, respectively. Laboratory pre-chlorination studies showed removal of phenol and penta- chlorophenol at chlorine dosages in excess of 250 mg/1. 7. KEY WORDS AND DOCUMENT ANALYSIS DESCRIPTORS b.lDENTIFIERS/OPEN ENDED TERMS C. COSATI Field/Group *Wood preservatives, *Activated sludge, *0xidation, Phenol, Creosote ^Completely mixed, *Chlorination, pentachloro phenol. 13/B 8. DISTRIBUTION STATEMENT 19. SECURITY CLASS (ThisReport) UNCLASSIFIED 21. NO. OF PAGES 108 20. SECURITY CLASS (Thispage) UNCLASSIFIED 22. PRICE EPA Form 2220-1 (9-73) 98 ftUSGPO: 1977 - 757-056/5479 Region 5-11 ------- |