PB83-217745 Evaluation of Catchbasin Performance for Urban Stormwater Pollution Control Environmental Design and Planning, Inc. Boston, MA Prepared for Municipal Environmental Research Lab, Cincinnati, OH Jun 83 U.S. DEPARTMENT OF COMMERCE National Technical Information Service ------- EPA-600/2-83-043 June 1983 EVALUATION OF CATCHBASIN PERFORMANCE FOR URBAN STORMWATER POLLUTION CONTROL Gerald L. Aronson David S. Watson Wil11am C. Pisano Environmental Design & Planning, Inc Boston, Massachusetts 02134 Grant No. R-804578 Project Officer Richard Field Wastewater Research Division Municipal Environmental Research Laboratory (Cincinnati) Edison, New Jersey 08837 MUNICIPAL ENVIRONMENTAL RESEARCH LABORATORY OFFICE OF RESEARCH AND DEVELOPMENT U.S ENVIRONMENTAL PROTECTION AGENCY CINCINNATI, OHIO 45268 ------- TECHNICAL REPORT DATA (Please read Inwnjct ions on the reverse before completing) I REPORT NO 2 EPA -600/2-83-043 3 &fLgNT’S ACCESSION NO 1DO5 21774 1 r 4 TITLE AND SUBTITLE B REPORT DATE EVALUATION OF CATCHBASIN PERFORMANCE FOR URBAN STORMWATER POLLUTION CONTROL June 1983 B. PERFORMING ORGANIZATION CODE REPORT NO 7 AUTHOR(S) B PERFORMING Gerald L. Aronson, David S. Watson, and William C. Pi sano ELEMENT NO 9 PERFORMING ORGANIZATION NAME AND ADDRESS 10 PROGRAM Environmental Design & Planning, Inc. 19 Fordham Road Allston, Massachusetts 02134 1 1-B0e 1Tn . IT/GRANi’NO R-804578 12 SPONSORING AGENCY NAME AND ADDRESS 13 TYPE OP REPORT AND PERIOD COVERED Municipal Environmental Research Laboratory- Cm., Office of Research and Development U.S. Environmental Protection Agency Cincinnati, Ohio 45268 OH 14 SPONSORING AGENCY CODE EPA/600/14 15 SUPPLEMENTARY NOTES Project Officer: Richard Field, Chief, Storm and Combined Sewer Program. Coml. (201) 321-6674; FTS 340-6674. lB ASS ’ ThIs report siesnarises the results of a field oriented data collection effort aired at evaluating the performance and utility of catchbasins from a pollutIon control standpoint me project was fanctisnal ly dl vided into three phases. with the fIrst being field data collection efforts and the last relegated to data reduction and analysis In the first phase of field work, three catchbasies In the West Rosbury section of Boston were selected from a can- didate list over 40 sites throughout the city The catchbasins chosen illustrated a diversity of land use and trsffit situations, as well us design type Each cutchbasln was then cleaned using traditional cethods Subsequent to clean- leg four runoff enencs were emnitored at each catchbasin to evaluate perforinaece itsitoring included inf lsent. effluent. srp liquid and sunip sediment Catthbasln pollutant removals were found to nary widely, fron a sInus ten percent (dIscharging prior swap accionajlatisns) to a posItive 90 percent. dependent on rainfall intensity and duration On the whole. catchbasins were shown to be quite effectIve for eel ida redaction. ia the order of 60—97 percent Catch- ba,in reemvale of associated pollutants such us chemical osygee demand (COO) and biochemical onygen deinued (BOO) were also significant, on the order of 10-56 percent and 54-88 percent. respectively. The second phase of wort involved the addition of an inlet strainer to each of the catchbesina as accseiplished in European practice The inlet strainers were cooiprlsed of a meter of B mesh (0 0937 In /2 36 sin) brass screee, per- recently amunted an an aleminic backing plate Runoff for an additional three eveets was nmeitored at each site during this phase of worh lelet strainers were found to provIde a marginal increase in pollutant removal (up to tee percent). In addition to that generated by the catchbasin. One interesting phensceinue was observed, ie that significant accina— lations of dirt, leaves, grit and paper were collected daring dry weather periods between stares ThIs work was subsisted in partial fulfillment of Grant lb R-8G4578 by Northeastern University. under joint spon- sorship of the U S Envi ronsental Protection Agency and the Division of Water Poll stisn Control. Cssemswnal th sf Massachusetts This report covers the period July 1978 to April 1980 and work was cosipleted April 1980 17 KEY WORDS AND DOCUMENT ANALYSIS DESCRIPTORS b IDENTIFIERS/OPEN ENDaD TERMS c COSATI ricld(Group Catchbasins, Combined sewers, Storm sewers, Surface waters, Runoff, Water pollution, Water quality Catchbasin effectiveness, Economic assessment, Pollution abatement, Storm runoff, Urban hy- drol ogy 13B 18 DISTRIBUTION STATEMENT RELEASE TO PUBLIC - 19 SECURITY CLASS (ThtsReportf UNCLASSIFIED 21 NO CF PAGES 91 20 SECURITY CLASS (Thu page) 22 PRICE EPA Fain, 2220—1 (Ran. 4—77) PREVIOUS EDITION Is 0050LETE ------- DISCLAIMER Although the Information described in this article has been funded wholly or in part by the United States Environ- mental Protection Agency through Grant No. R—804578 to Envir- onméntal Design & Planning, Inc., it has not been subjected to the Agency’s required peer and administrative review and therefore does not necessarily reflect the views of the Agency and no official endorsement should be inferred. I I ------- FOREWORD The Environmental Protection Agency was created because of increasing public and government concern about the dangers of pollution to the health and welfare of the American people. Noxious air, foul water, and spoiled land are tragic testimony to the deterioration of our natural environment. The complexity of that environment and the interplay between its components require a concentrated and integrated attack on the problem. Research and development is that necessary first step in problem solution and It involves defining the problem, measuring its impact, and searching for solutions. The Municipal Environmental Research Laboratory develops new and improved technology and systems for the prevention, treatment and management of wastewater and solid and hazardous waste pollutant discharges from municipal end community sources, for the preservation and treatment of public drinking water supplies and to minimize the adverse economic, social, health, and aesthetic effects of p01 lution. This publication Is one of the products of that research, a most vital communications link between the researcher and the user community. The deleterious effects of storm sewer discharges and combined sewer overflows upon the nation’s waterways have become of increasing concern In recent times. Efforts to alleviate the problem depend in part upon the development of integrated technologies involving non—structural best management practices with structural storage and treatment concepts. This report presents the summary of a field oriented data collection effort aimed at evaluating the performance and utli ity of catchbasins from a pollution control standpoint. CatchbasinS were monitored during seven runoff events and performance assessed. During three of the events specially designed insert strainers were used to assess their efficiency. Francis 1. Mayo, Director Municipal Environmental Research Laboratory iii ------- ABSTRACT This report summarizes the results of a field oriented data collection effort aimed at evaluating the performance and utility of catchbasins from a pollution control standpoint. The project was functionally divided into three phases, with the first two being field data collection efforts and the last relegated to data reduction and analysis. In the first phase of field work, three catchbasins In the West Roxbury section of Boston were selected from a candidate list of over forty sites throughout the city. The catchbasns chosen ill ustrated a diversity of land use and traffic situatIonS, as well as design type. Each catchbesin was then cleaned using traditional methods. Subsequent to cleaning four runoff events were monitored during the month of December, 1979 at each catchbasln to evaluate performance. Monitoring included; lnfluent,.efflUeflt, sump liquid and sump sediment. Catchbasln poiiutantremoval 5weref0 uu1dt0 tY widely, from a minus 10% (discharging prior sump accumulations) to a positive 90%. On the whole, catchbasins were shown to be quite effective for solids reduction, in the order of 60—97%. Catchbasin removals of associated pollutants such as Chemical Oxygen Demand (COD) and Biochemical Oxygen Demand (BOD) were also significant, on the order of 10—56% and 54—88%, respectIvely. The second phase of work involved the addition of an inlet strainer to each of the catchbaslns as accomplished In European practice. The inlet strainers were comprised of a number B mesh (0.0937 i n./2.36mm) brass screen, permanently mounted on an aluminum backing plate. Runoff for an additional three events was monitored at each site during the month of January, 1980. Inlet strainers were found to provide a marginal increase In pollutant removal (up to 10%), In addition to that generated by the catchbasln. One Interesting phenomenon was observed, In that significant accumulations of dirt, leaves, grit and paper were collected during dry w ather periods between storms. This work was submItted In partial fulfillment of Grant No. R804578 by Northeastern University, under Joint sponsorship of the u.s. Environmental Protection Agency and the Division of Water Pollution Control, Commonwealth of Massachusetts. This report covers the period July 1978 to April 1980 and work was completed April 1980. iv ------- I ntroduct ion I • I Foreword 1.2 Purpose of Study I .3 Background 1.4 Historical Review 1.5 Description of the Study/Report Format Concl us ions Recommendations Detailed Catchment Area DescrIptions 4.1 Criteria Used in the Selection of Catchbas ins 4.2 Individual Site DescriptIons Sample Collection and Analytical Proced ures 5.1 Field Sampling Procedures—Liquid Samples 5.2 Field Sampling Procedures—Solids Samples 5.2.1 5.2.2 5.3 Other Results of Program 6.1 Summary of Results—Liquid Samples 6.2 Summary of Results—Sump Sediment TABLE Q.E CONTENTS Foreword Abstract List of FIgures List of Tables List of Abreviatlons and Symbols Acknowledgments Chapter I Chapter 2 Chapter 3 Chapter 4 Chapter 5 Chapter 6 ii 111 vi i lx x l xli 2 4 6 8 10 11 11 12 21 21 27 27 27 30 32 32 57 Sump Sediment Samples Inlet Strainer Samples FIeld Determinations the Catchbasin MonitorIng V ------- 6.3 Summary of Results—Influent 65 Stral ners 6.4 RevIew of Catchbasin MonItoring 67 Data Chapter 7 Analysis of Catchbasin Cleaning Costs in City of Boston 69 7.1 Foreword 69 7.2 Boston Catchbasin Cleaning Costs 69 7.3 Catchbasln Cleaning Costs Comparison 70 7.4 Economic Analysis of Increased Catch— basin Cleaning FrequencIes 72 References and BIbliography 78 vi ------- LIST E FIGURES Page Figure I Representative catchbasln designs In the 3 United States and Canada. FIgure 2 Locational map of West Roxbury. 13 Figure 3 LocatIonal map of catchbasin monitoring sites. 14 FIgure 4 SprIng Street catchbasln configuratIon. 15 FIgure 5 Map of Spring Street drainage area. 16 FIgure 6 Baker Street and Glenhaven Road catchbasln 18 configurations. Figure 7 Map of Baker Street end Glenhaven Road 19 drainage areas. FIgure 8 Photographs of Baker Street and Glenhaven 20 Road catchment areas. Figure 9 Diagram of sampling and sample handi Ing— 22 liquid samples. FIgure 10 Photograph of catchbasln at Spring Street 24 and pre—sump sampling at Baker Street. Figure II Gutter and effluent grab sampling procedures. 25 Figure 12 Diagram of sampling and sampling handling— 28 solids samples. Figure 13 Photographs of Inlet strainer unIt. 29 Figure 14 Photographs of debris collection and 31 collected debris from strainer bag. Figure 15 Typical plots of Total Solids Influent/ 58 effluent concentrations. Figure 16 Typical plots of TSS influent/effluent 59 concentrations. vii ------- Figure Ii Typical plots of COD influent/effluent 60 concentrations. FIgure 18 Typical plots of BOD Influent/effluent 61 concentrati ons. Figure 19 Composite plot of sediment analysis 62 for Spring Street. Figure 20 Composite plot of sediment analysis 63 for Baker Street. Figure 21 Composite plot of sediment analysis 64 for Glenhaven Road. viii ------- Tabi e LIST QE TABLES P ge I SUMMARY OF ANALYTICAL METHODS 2 SIEVE SERIES UTILIZED FOR SUMP SEDIMENT ANALYSIS 27 3 CHRONOLOGY OF CATCHBASIN MONITORING PROGRAM 33 4 CATCHBASIN MONITORING DATA — SPRING STREET 12/5/79 34 5 CATCHBASIN MONITORING DATA — BAKER STREET 12/5/79 35 6 CATCHBASIN MONITORING DATA — GLENHAVEN RD. 12/5/79 36 7 CATCHBASIN MONITORING DATA — SPRING STREET 12/7/79 37 8 CATCHBASIN MONITORING DATA —BAKER STREET 12/7/79 38 9 CATCHBASIN MONITORING DATA — 12/7/79 39 10 CATC1-IBASIN MONITORING DATA — 12/12/79 40 11 CATCHBASIN MONITORING DATA — 12/12/79 41 12 CATCHBASIN MONITORING DATA 12/12/79 42 13 CATCHBASIN MONITORING DATA 12/27/79 43 14 CATCHBASIN MONITORING DATA 12/27/79 44 15 CATCHBASIN MONITORING DATA 12/27/79 45 16 CATCHBASIM MONITORING DATA 12/28/79 46 17 CATCHBASIN MONITORING DATA 12/28/79 47 18 CATCHBASIN MONITORING DATA 12/28/79 48 19 CATCHBASIN MONITORING DATA 1/11/80 49 20 CATCHBASIN MONITORING DATA 1/11/80 50 21 CATCHBASIN MONITORING DATA 1/11/80 51 GLENHAVEN RD. SPRING STREET BAKER STREET — GLENHAVEN RD. — SPRING STREET — BAKER STREET — GLENHAVEN RD. — SPRING STREET — BAKER STREET — GLENHAVEN RD. — SPRING STREET — BAKER STREET — GLENHAVEN RD. ix ------- Table P ge 22 CATCHBASIN MONITORING DATA — SPRING STREET 1/14/80 52 23 CATCHBASIN MONITORING DATA — BAKER STREET 1/14/80 53 24 CATCHBASIN MONITORING DATA — GLENHAVEN RD. 1/14/80 54 25 AVERAGE FLOW RATES FOR RUNOFF EVENTS MONITORED 55 26 MASS AND PERCENT REMOVALS WITHOUT INLET STRAINERS 56 27 MASS AND PERCENT REMOVALS WITH INLET STRAINERS 56 28 MONITORING OF SUMP LEVELS IN CATCHBASINS 65 29 RESULTS OF THE INFLUENT STRAINER STUDIES 66 30 PRESENT BOSTON CATCHBPtSIN CLEANING COSTS 71 31 PERTINENT DATA — WEST ROXBURY, BOSTON TEST CASE 73 32 WWTP SOLIDS HANDLING COSTS W. ROXBURY CASE EXAMPLE 75 33 COMPARATIVE ECONOMICS OF CATCHBASIN CLEANING FREQUENCY 75 ------- ABBREVIATIONS ANQ XMBOLS Abrev I ati on cf cubic feet cfs cubic feet per second cm centimeter cm/h centimeter per hour fpm feet per minute fps feet per second ft feet ft 2 square feet ft 3 cubic feet g gram h hour ha hectare ID inner diameter in/h inch per hour lb pound kg kilograms km kilometer liter m meter m 3 cubic meter mg/i mu ligram per liter ml milliliter mm millimeter rn/s meters per second vs. versus Symbols BOD Biochemical Oxygen Demand (5 days) COD Chemical Oxygen Demand TKN Total KJeldahl Nitrogen TP Total Phosphorus TSS Total Suspended Solids VSS Volatile Suspended Solids WWTP Wastewater Treatment Plant Percent x l ------- ACKNOWLEDGMENTS The authors would like to commend the Environmental Design & Planning, Inc. (EDP) staff who worked so hard to make this program a success. This study, through its efforts collected the first simultaneous performance data on catchbaslns. We would like to particularly express appreciation to the members of the EDP field crew, including David Walsh, Stephen Becrgstrom and Robert SilverIo for their many hours of inclement weather endured. Final ly, last but certainly not least, we would I Ike to express our sincerest appreciation to Nora W. Scanlan and Nickle Kronenberg for their patience in typing this report. Northeastern University (NU)was the recipient of the combined grants from the U.S. Environmental Protection Agency and the Division of Water Pollution Control, State of Massachusetts. Drs. Frederic C. Blanc, James C. O’Shaughnessy and Professor Richard J. Scranton were the project officers for Northeastern University. Environmental Design & Pianning, Inc. was the major engineering subcontractor to NU for the project. Mr. Gerald Aronson, Executive Vice President, EDP, was the project manager. Mr. David Watson, EDP’s Supervisor of Field Services supervised all the field work. Mr. David Kippenberger, EDP’s Supervisor of Technical Services supervised fabrication of the inlet strainers and special sampling equipment used In this program. Dr. William C. Pisano, President, EDP, was the principal investigator for this project and provided aid in report preparation. The final report was prepared by EDP, mc. PROJECT OFFICERS/SPONSORS Richard Field, Chief Robert Turkeltaub, Staff Engineer Storm and Combined Sewer Section Wastewater Research Division Municipal Environmental Research Laboratory U.S. Environmental Protection Agency Charles Button, Chief Engineer Boston Water & Sewer Commission Boston, Massachusetts Thomas McMahon, Director Water Resources Commission Massachusetts Division of Water Pollution Control Westboro, Massachusetts Northeastern University Department of Civil Engr. Boston, Massachusetts xii ------- #APTER 1 INTRODIJCT ION 1 • I Foreword The purpose of this study is outlined In Section 1.2. Background materials describing catchbasin functions and American and European design and maintenance practices are given in Section 1.3. An historical review of literature dealing with the pollution control aspects of catchbasins is given in Section 1.4. Section 1.5 contains a description of the study and report format. 1 .2 Pijreose j _____ Control of stormwater runoff is a problem of increasing importance in the field of water quality management. Over the past 70 years, there has been extensive use of catchbasins for coarse material removal from stormwater runoff, yet catchbasin pollutant removal effectiveness has not been evaluated in depth. In a recent study entitled “Catchbasin Technology Overview and Assessment,”(l) it was recommended that monitoring programs should be undertaken to: 1) determine the impact of best management practices in reducing sol ids and other pollutant loads in surface runoff that must be collected from urban areas and, introduced to the sewer through catchbasins; 2) evaluate the effectiveness of closely monitored catchbasin cleaning programs with respect to impacts of cleaning frequency and, techniques on solids carryover as well as general pollution abatement and; 3) determine the extent to which sol ids deposition can be mitigated by properly designed and functioning catchbasins. These recommendations were based on an analysis of catchbasifl pollutant removal performance using secondary data synthesized from a variety of sources. Direct and concurrent measurement of influent and effluent pollutant characteristics had not been previously performed. Prior measurements Included either street surface pollutant characteristics or spot grab sampling of catchbasifl sump volumes. The basic thrust of the research was to careful ly monitor simultaneous Influent and effluent characteristics for several catchbasinS in the Boston Metropol itan area. The primary emphasis of this study focused on the characterlzaton of the pollution load attenuation characteristics of a catchbasin. A secondary goal examined the pollutan$ reduction effectiveness of insert strainers In several catchbeslns within the study area. 1 ------- These dev.iceS are commonly used in European practice and have been shown effective for removing gross floatables and settleable solids, such as cigarette butts, eaves, lawn clippings and pa per. 1 .3 kçr iind !A catchbasin is defined as a chamber or well, usually built at the curbline of a street, for the admission of surface water to a sewer or subdra ln, having at its base a sediment sump designed to retain grit and detritus below the point of overflow. Because some communities call any device that receives stormwater a catchbasifl, the distinction is made between those devices that intentionally trap sediment and those that do not. In this report, the device that traps sediment Is what is referred to as a catchbasln. Stormwater runoff In urban areas normally fiows for a short period of time in the gutter and is diverted by an inlet structure. leading to an underground conduit or open channel for transportation to a receiving body of water. The underground conduit, either a storm or combined sewer, may be protected from clogging by catchbasins built in conjunction with the inlets. Catchbasins serve two main purposes: to prevent sewer gases from escaping through the inlet gratings and; to prevent heavy or large solid matter from the street from entering the sewers. The trapping of sewer gases is accomplished by a water seal. The retention of soi Ids is achieved by providing a sump or settling basin in which the heavy solids settle to the bottom, w hi I e the light sol I ds float on top. Water drai ns to the sewers through the outlet of the catchbasin which is generally a few Inches below the water surface. These basins are normally built under the inlet gratings or opnings, either under the gutter or just back of the curb. Occas,onally, one catchbasin will serve two or more standard inlets. In American practice, a standard catchbasin appears to be nonexistent (I). Attempts at uniformity within individual cities (Figure 1) show varying degrees of success. The effectiveness of the water seal gas trap is an Important issue in American practice, since it is directly proportional to the antecedent dry period and the corresponding evaporation rate, in addition, organics in the catchbasifl if allowed to accumulate, may decompose with time and contribute odors similar to sewer gas even if the water seal has not evaporated. In Europe catchbasin sizes vary, except in Germany where they have been standardized. Two types of catchbasins are used: a simple depositary type and another type generally called 2 ------- 2 It — 0 Ii. ATLANTA TORONTO Figure 1. Representative catchbasin designs in the United States and Canada. Source: Mstcalf & Eddy, Inc. (1) 0 “4 z C 0 NEW YORK SAN FRANCISCO 3 ------- a “selective” catchbasin In which a bucket sieve or some other means is used to select and separate various solid materials. The latter type varies greatly in different countries and various cities. The buckets provide an easy and rapid method for cleaning by street crews. As part of this effort, Inlet strainers were fabricated and installed in the monitored catchbasins to assess their pollutant removal effectiveness, thus simulating the European practice. European catchbaslns tend to be small r in size, reflecting closer spacing, i.e., smaller drainage areas per unit. Most European cities are located on relatively flat terrain with long—duration, low—intensIty, high—frequency rain patterns and most catchbasins do not include gas traps because of the frequent flushing by storm runoff. Catchbaslns are usually circular in shape. A perforated removable bucket is used to catch large objects, and the runoff flow Is rel led on to carry the smaller material on into the sewer. There is a definite tendency in most of the textbooks in Europe to discount, or not recommend, depository type catchbasins, because the material that accumulates with the water is subject to fermentation odors and other problems of stagnation. When depositary type basins are requlred, a siphon modification, in which a separation baffle is Installed, Is often used. The solid material is left in one compartment and the flow Is basically drained through the siphon and underneath the baf f I e. 1.4 HIstorical Review Historically, the purpose of catchbasins is to prevent sewer clogging by trapping coarse debris and to prevent odor emanations from the sewers by providIng a water seal. The prevention of sewer clogging was especially Important prior to the existence of good quality street pavements. In areas where streets were partially or wholly unpaved, significant quantities of stone, sand, manure and other materials were washed into the sewer system during periods of rainfall. Al so, during the earl ier years of sewer construction, lIttle attempt was made to maintain self—cleaning velocIties In sewers of at least .61m/s (2 fps) (2). The u5efulness of catchbaslns was considered marginal as far back as 1900 (3). Most modern texts generally agree and only provide short disclaimers regarding the value of catchbasins, except where deposition of large amounts of grit Is expected In the sewer without them (4,5). Despite the purported reduced need for catchbaslns, they are stilt used widely In many parts of the country (6). 4 ------- Little investigation has been conducted on the hydraulic characteristics of flow within a catchbasin. The University of ill Inols conducted some investigations and concluded that catchbaslns are hydraulically inefficIent (7). In another study of hydraulic characteristics by the APWA, it was found that for all practical purposes complete mixing occurs within a catchbasin (8). This seems to fit In with the University of Illinois’ studies which indicated that a catchbasin is a poor sedimentation device because of its tendency to re5uspend the solids in the sludge deposits even at moderate inflow rates. Attempts by the University of Illinois group to improve settling by baffling, showed additional adverse effects. However, a more recent study of catchbasins with large antecedent debris contents indicated that only about one percent of the antecedent content washed out (9). it was concluded, however, that the material flushed out as the initial slug would have a substantial p01 lutlonal impact on the receiving waters. In the APWA study, It was also concluded that catchbasins may be one of the most important singie sources of pollution from storrnwater flows (8). All of the studies concluded that catchbasins cannot efficientiy satisfy the competing objectives of good hydraulic characteristics and solids retention. Pertinent conclusions relating to catchbasln pollutant removal effectiveness from a recent assessment study (1) are excerpted as follows: 1. Existing catchbasins exhibit mixed performance with re5pect to pollution control. The trapped liquid purged from catchbaslns to the sewers during each storm generally has a high poll ution content that contributes to the intensification of first—flush loadings. Countering this negative impact Is the removal of poll utants associated with the solids retained in, and subsequently cleaned from, the b&sin. 2. The collection of conclusive field data is hindered by the prevailing poor conditions found in most basins resulting from under financed and poorly monitored cleaning programs. 3. Approximately 95 to 98% of the BOD load in the liquid contained in a catchbasin prior to a storm will be displaced to the sewer by a rainfall of as little as 0.05cm/h (0.02 ln./h) lasting four hours. As a side note, the displacement of catchbasin surnp volume is also dependent on the size of the tributary area as well as the rainfall intensities. This is approximately equivalent to the waste discharged by one person in one day. -. 5 ------- 4. On an annual basis, the amount of material that would be retained in a catchbasin is given in the foliowing tabulation: Percentage j Mater ia -i Retained J.j Ce-tchbasln jg Individual Storm Range 1 Material Retained ( Percentage) High Total soiids 42.1 75.0 Vo latilesoiids 15.2 25.5 BOD5 15.5 25.6 COD 7.5 14.1 KJeldahI nitrogen 14.6 27.4 Nitrates 9.5 17.1 Phosphates 2.3 6.0 Total heavy metals 37.4 64.4 Total pesticides 13.6 29.7 5. From a pollution abatement standpoint, the benefits of catchbasins appear limited. For example, the net removal of BOD from a well—designed and maintained system of catchbaslns based on conformance to observed data, is expected to be in the range of five to 10% of the applied load. ,A potential exception may be the removal of heavy metals which, as tabulated above, could be significant. M.I j these conclusions reached ir ni desk—top 1 L .i i Qm x i i i.e., cel-chbasin sump information from San Francisco and nationai assessments of street load solids characteristics. These results e.r tentative e.n4 ± uiti. . JLtLn. j Ln.g Lr..Q ± .p cIm c. mr Qm n.i. from programs such as those conducted In this study.” 1.5 DescriDtion j jh. Study/Report Format This report details a field monitoring effort aimed at assessing the pollutant removal effectiveness of catchbasins. As mentioned in the prior sections, aithough catchbasins have been in use for roughly 70 years little actual monitoring of performance has been conducted and no studies have collected both influent and effluent data simultaneously. During the period of November 1979 through January of 1980 a total of seven runoff events were monitored at three separate catchbasin sites, yielding a total of 21 runoff events monitored. All of the catch— basins were located in the West Roxbury section of the city of Boston. Anaiyses were conducted for Total Suspended Solids (TSS), Volatile Suspended Solids (VSS), Chem ical Oxygen Demand (COD), 6 ------- Biochemical Oxygen Demand (5 days) (BOD), Total KJeldahl Nitrogen (TKN), Total Phosphorus (TP), sediment particle sizing and, percent volatile. Special analyses were conducted to assess the sump liquid and solids conditions prior to and subsequent to the runoff events. Inlet strainers similar to those used In Europe were specially fabricated, Installed and monitored over three runoff events to assess their impact on overall performances. Site selection and details of the various catchbaslns monitored are described in Chapter 4. Sample collection and analytical procedures are described in Chapter 5 and finally, monitoring results are shown in Chapter 6. Estimates of catchbasin cleaning costs In the City of Boston are presented in Chapter 7 and compared with national average results. 7 ------- CHAPTER 2 CONCLUSIONS The conclusions of this investigation are as follows: 1. Catchbasins were very effective in removing suspended solids— related pollutants from influent waste streams. Pollution mass reductions of 60 to 97 percent suspended solids, 48 to 97 percent VSS for relatively low intensity storms during December and January, 10 to 56 percent COD, and 54 to 88 percent BOD were observed. No data were obtained for summer type storms. 2. The limited data collected indicated that catchbasins do little with respect to nutrient removal. 3. Though the total mass of the influent to the catchbasins varied widely, the concentration profiles of both the influent and effluent with time were very consistent. 4. Sieve analyses of catchbasin sump sediment samplings (taken 21 times over the course of the evaluation program) yielded results consis- tent with those found in the literature. 5. Sump sediment was highly organic-—on the order of 60 to 90 percent, depending on particle size range. 6. Inlet strainers were designed, fabricated, and installed on the three test catchbasins for three runoff events each. The strainers consistently retained significant dry weather accumulations ranging from 150 to 500 g of dry solids per day. 7. Accumulation of dry weather solids in the catchbasin inlet strainers seemed to be primarily a function of degree of vehicular traffic at each location. 8. Inlet strainers offered a slight gain in overall pollutant removal efficiency of catchbasins, but they would not be functional on a large scale. These devices are effective for the removal of course 8 ------- material that could cause visual upsets. Problems with clogging and potential for decomposition and ultimate discharge of pollutants negated their value unless weekly (or more frequent) maintenance was employed. 9 ------- CHAPTER 3 RECOMMEN DAT IONS The following are recommendations generated from this study. I. Catchbasins, if maintained, are an efficient pollutant reduction/maintenance tool and should continue to be utilized. 2. Similar monitoring studies such as conducted in this study should be conducted in other geographic areas to substantiate the findings of this study. Regions recommended are the midwest, south and west because of their differences in climate, hydrology and system characteristics. 3. Since energy dissipation is of prime importance to the function of catchbasins, further research should be conducted into simplistic ways of reducing infiuent energy. 4. FIeld scale demonstration of closely monitored concurrent street sweeping, catchbasin cleaning and sewer maintenance programs should be conducted in varying terrain for both separate and combined sewerage systems to investigate the optimal mix of best management practices from maintenance and pollution control viewpoints. The main emphasis of the studies should be devoted to carefully monitoring the separate and Joint effectiveness of these techniques and conclude with an assessment of the impacts of cleaning frequency and mechanisms of sol ids carryover, general poliutlon abatement and associated costs. 5. Additional monitoring studies should investigate the effectiveness of catchbasins for removal of heavy metals as well as oil and grease poll utant removals. ------- CHAPTER 4 DETAILED CATCHNENT AREA DESCRIPTIONS 4.1 Criter1 a Used in ±J Seleclion j Catctibaslfls Although, it would logically seem that site selection for a catchbasin monitoring program would be a simple matter, that was not the case. Prior to inspection of possible candidate sites an exhaustive review of detailed sewer maps for approximately 3000 acres of the City of Boston was conducted. This review of mapping information provided a pre—screen for candidate sites. Criteria utilized in the pre—screen were as follows: 1) All catchbasins to be monitored had to be indicated to discharge directly to a receiving manhole and not into the sewer line; 2) The catchbasln had to have a readily definable fixed tributary area and; 3) Traffic patterns and land use density had to vary. Unfortunately, it seems that most catch— basins in Boston are connected directly to the adjacent receiving sewer without access formed by a manhole. For the purposes of this study, it was deemed that access to the catchbasin discharge via a manhole connection would be most desirable for the purpose of monitoring. The catchbasin effluent sampling would be conducted at the discharge of the catchbasin to the receiving sewer in a manhoie. As a result of this criteria, of the literally thousands of catchbas Ins within the area, a list of approximately 50 candidates were generated from the mapping review. This list was reduced to 40 potentIal sites on the basis of the other two criteria. Approximately 40 catchbasins in the metropolitan area were field inspected prior to choosing the three whose performance was to be evaluated during this study. The three specific criteria used In the final selection are described below in the order of importance. Of foremost value to the study was the selection of at least two different catchbesin design configurations. The second priority was to assure that all catchbasfn catchment areas were of varying tributary acreage and more importantly, showed differences of automobile traffic density and surrounding land use. Thirdly, the physical dimensions of the catchbasin and the receiving manhole were reviewed to ensure proper space and access required for sampling equipment. The most important requirement of the monitoring manhole was adequate height between the outlet and the sewer free water surface to permit placement of a specially constructed sampling device. The receiving manhole also had to be large enough to house two sampling devices (influent 11 ------- and effluent) and a discharge flow monitor. After careful review of the approximately 40 catchbasins, three test sites were chosen in the West Roxbury section of Boston. 4.2 IndivIdual Si±eDes riptioitS The West Roxbury section of Boston is depicted In Figure 2 and may be typified as moderate income residential, with mixed commercial occurring primarily along several main road tracts. General housing density in the area Is moderate, with lawns and streets in generally good condition. The sewer system In this area Is entirely separated (as constructed), with the exception of a few streets. The approximate median age of the housing in the area is 40 years. Drainage from the area discharges rprimarlly into the Upper Charles River through an extensive drainage system. Topography in the area varies from moderately hilly to flat. The three catchbaslns selected for the study, which are shown in Figure 3, are located on the corners of Spring and Alaric Streets, Baker Street and Joyce Kilmer Road and Glenhaven Road and Keystone Street. Ee.ch site area is described In detail below. The catchbasln at Spring and AlarIc Streets Is of a different configuration than the other basins selected. Whereas the other two catchbaslns selected are comprised of single sumps, this design utilized a double surnp arrangement. Figure 4 Is a diagram of the catchbasin. Gutter flow Is initially coi lected by a shallow b sln with a non—trapped outlet pipe, eight inches in diameter, discharging the flow into a oval shaped settling basin approximately three feet by four feet In plan and 3 1/2 feet deep.ThesumpundertheCurb measures24 inchessquarewith six inches of depth beneath the discharge inlet. The grates covering all the selected catchbasins are square with lengthwise silts averaging two inches In width. The area tributary to the Spring Street site Is shown in Figure 5 and equals approximately 3.42 acres. The area along Spring Street is characterized by eight old large single family houses and a mechanic’s garage. Open space comprises about 30% of the catchment area along Spring Street. The drainage area along Alaric Street and Alaric Terrace represents about 27% of the total catchment area. The street slope is about 20%. Traffic on Alaric street Is light and services a very srnal I residential area. Conversely, Spring Street is a major commercial four—lane traffic route with parking on both sides of the street. The area is generally littered with paper and other debris and exhibited high rates of grit accumulation over short periods of time. 12 ------- .1 ( Figure 2. Locational map of West Roxbury. 13 ------- Figure 3. Locational map of catchbasin monitoring sites. meters LEGEND • Monitoring site o Catchbasin Scale o ioo 200 300 feet 400 800 4 N 14 ------- TOP VIEW 48 Figure 4. Spring Street catchbasin configuration. PROFILE STREET A Slope Unlwown To SEWER 48’ ‘ li -I T T CURB 15 ------- Figure 5. Map of Spring Street draitiage area. TEST CATCHBASJN DRAINAGE AREA BOUNDARY C, )Q. — SCALE meters I I O 10 20 30 feet — — 0 40 80 16 ------- The catchbasin design of the sites on Baker Street and on Gienhaven Road (Figure 6) are very similar and conform to the typical configuration referred to as the SAN FRANCISCO style. The only difference between the basins other than capacity, is how gutter runoff enters the sumps. The Baker Street site has a brick table constructed one foot below the street grating. Runoff then drops from this table to the water surface, approximately two feet below. The sump is oval shaped (four feet by 4—1/2 feet) and drops 3 feet below the invert of the outlet pipe. The outlet pipe diameter Is eight inches. This site is the smallest area In tributary acreage as shown in Figure’ 7.Vehicular traffic Is moderate in comparison to observed traffic along Spring Street. Total catchment area size is approximately 1.56 acre. Flow to the catchbasln comes from only one direction, on Baker Street. The street Is a two—laned, medium—traveled secondary road. It Is without curbstones for 75% of its length; however, the pavement over this area is continuous to the sidewalk. General condition of the pavement is very good. The Baker Street cetchment area’s land use is shown in Figure 8 and is characterized by eleven small single family dwellings with lawn areas averaging 300 square feet and single car paved driveways. Few trees and bushes grow near the roadside. On—street parking is exhibited to a relatlveiy high degree due to two factors. First, many households own two automobiles, but have driveway space for only one. Second, a pre—elementary school Is located on the opposite side of the street, responsible for increasing daily children delivery and pickup parking. School bus traffic to the school comprises the only heavy vehicle traffic on Baker Street. Overall street appearance is always very clean. The catchbasln at the Glenheven Road location is of the SAN FRANCISCO type catchbasin design. The sump is located directly below the street grating, with a five—foot drop from the street to the water surface. The capacity of this sump is greater than the other two catchbosins, measuring 5—1/2 feet in diameter and dropping five feet below the eight—inch outlet pipe invert. Flow to the catchbasin comes from both ends of Gienhaven Road, yielding a total tributary area of 1.21 acre. Glenhaven Road is located within a residential area with only iight vehicular traffic. Vehicular traffic is slight In comparison to observed traffic along Spring Street. The entire area is curbed and has paved sidewalks. Many large older trees line both sides of the street, yielding a very high leaf and twig concentration in the catchbasin sediment. Street pavement is in good repair. 17 ------- To SEWER 54” BAKER STREET To SEWER 48” PROFILE TOP VIEW CURB K “ PROFiLE GLENHAVEN ROAD TOP VIEW Figure 6. Baker Street and Glenhaven Road catchbasin configurations. 18 ------- Figure 7. Map of Baker Street and Glenhaven Road drainage areas. 4 N meters i I 0 10 20 .30 feet — — — o 40 80 Iw j I-jo I ‘U I)- I 0-i L C .. T ST C ATC H BASIN DRAINAGE AREA BOUNDARY SCALE ------- Baker Street catch ent area Glenbaven Road catcluient area Figure 8. Photographs of Baker Street and Clenhaven Road eatchment areas. 1%) -I -o ------- CHAPTER 5 SAMPLE COLLECTION AND ANALYTICAL PROCEDURES l-ntrod ucl Ion Successful monitoring of catchbasin performance required sampling from several waste streams containing relatively high amounts of grit and floatable material. In order not to bias the catchbasin performance results, a series of special devices were fabricated to allow for representative sampling of the various waste streams. This chapter outlines the various sample types and procedures used in the field, as well as analytical procedures utilized in the laboratory. 5.1 Field pling Proce ures—Liqu-id mples The catchbasin monitoring program was designed to collect representative and simultaneous influent and effluent samples, to assess true pollutant removal performance. As mentioned in Chapter 4, considerable effort was expended in selecting catchbasins suitable for monitoring. Prior to the initiation of the sampling program, each catchbasin was cleaned by the Boston Water and Sewer Commission cleaning crews, using typical clamshell bucket equipment. No attempt was made to further clean the catchbasins beyond that accomplished by the clamshell bucket, since the purpose of this study was to assess the effectiveness of catchbasins on a” real I Ife” basis. Clamshell bucket cleaning equipment is the most predominate type used in the United States for catchbasin cleaning and although convenient, is not totally effective. Subsequent to cleaning, each catchbasin had at least 12 inches of residual materials on the bottom and substantial accumuiations stuck to the sidewalls of the sump. Undoubtedly, the remaining residuals effected the overall catchbasin performance. Figure 9 depicts the sampling and analytical procedures used for the various liquid samples taken. As may be noted from the figure, samples taken included: sump grab sample prior to runoff event (pre—sump sample); gutter or influent samples at the inlet to the catchbasin during storm event; effluent samples taken at the outlet to the receiving sewer manhole during storm event and finally, samples taken in the sump subsequent to the runoff event (post—sump sample). Sampling of the various liquid sample types were conducted for al I runoff events at the three catchbasins monitored. 21 ------- I. Pre Sump Sample TSS I vsS 1 liter Sample COD BOD TKN* TP* - Influent Sample — I Effluent Sample Two Samples 1—2 Gallon Sample 350 ml 1 Liter TSS COD I BOO TKN* I VSS TP* I TSS vSS Post Sump Sample 1 Liter Sample Poured back & forth 3x 100 m l - Sample I COD BOD TKN* TP* - S Shaken lOOmi TSS I VSS I COD BOD TKN* TP* *Selected Samples F I Figure 9. Diagram of sampling and sample handling—liquid samples. ------- Initially, the primary thrust of the catchbasin monitoring program was to be conducted by automated sampling and flow gaging equipment. Since both the influent and effluent samples would have significant fractions of grit and sin_ce commercial sampling equipment will not adequately capture grit, special sampling equipment had to be designed. The special sampling equipment was in essence, a mechanical grab sampler. Monitoring of the influent utilized a specially constructed mechanical scoop to take gutter samples and discharge them directly into the appropriate sample bottle in a sample bottle cassette. Effluent samples were collected by passing a sampling scoop through the free effluent discharge Into the receiving sewer manhole, collecting a complete “slice” of the discharge volume and discharging the collected fraction into a sample bottle In a sample bottle cassette.’ During the sampling program both automated end manual techniques were employed. Since EDP field crews were able to be onsite during most of the runoff events, grab sampling techniques were used for those events. The grab sampling procedures employed are shown in Figures 10 and Ii. Figure 10 shows the pre—sump sampling procedure. A specially designed sample bottle holding device was constructed for this purpose to allow obtaining cross sectional sump samples. lnitlaliy, a sample bottle was loaded in the device and the trigger released, tightly sealing the bottle closed. The bottle was then lowered in the surnp to the appropriate depth(s) and the trigger mechanism pulled, allowing the bottle to fill. At any time, release of the trigger mechanism would close off the sample bottle, allowing movement to another position for cross— sectional sampling. The post—sump sample was taken In a similar manner as the pre—sump sample (within two to five minutes of cessation of runoff). Grab sampling of the gutter influent and catchbasln effluent flow is shown in Figure II. Grab sampling of the gutter was accomplished by collecting a cross section of the flowing gutter materials and depositing the contents into a sampie bottle. in all cases the gutter area where samples were taken was maintained clean prior to runoff events, to ensure no sampling bias. Influent grabs were taken via a series of scooplngs deposited into two bottles, as shown in Figure 9. Due to the great difficulty in obtaining a thoroughly mixed 100 ml fraction of a one liter sample, a single 350 ml sample was used for the suspended solids determination. The second sample was used for the determination of all other parameters. * it should be pointed out that even this method of sampling would not account for the slower movement of the particulate (Foot note continued on top of page 26) 23 ------- F ’.) Catchbasin at Spring Street Figure 10. Photograph of catchbasin at Technician taking pre—suinp sample at Baker Street Spring Street and pre—sump sampling at Baker Street. ------- Collection of gutter grab samples Figure 11. Cutter and effluent grab sampling procedure. Collection of full volume effluent samples C )’ -4 rn ------- *flowfleld compared to the liquid flowfield and samples are only taken for an instantaneous period of time as opposed to throughout the entire influent — effluent period. These deficiencies disallow totally representative sample collection. Effluent grab sampling and flow monitoring was accomplished by suspending a sampling pall beneath the discharge of the catchbasln to the receiving sewer manhole for a timed period. In this manner, both flow and quality were determined simultaneously. The total volume sampled was returned to the laboratory for analysis. The total volume collected and measured per sampling interval was divided by the collection time to yield flow rate. The collected effluent sample, in the order of one to three gallons, was then mixed by pouring from one pail to another three times. During the final pouring, an approximately 100 ml sample was decanted rapidly into a graduated cylinder for the suspended solids determination. All other parameters analyzed for were determined from samples drawn from the large pail. Table I presents a summary of the analytIcal procedures used during the cetchbasin monitoring program. Replicate analyses were performed every sixth to eighth sample for all collected sets. TABLE I JMM R 3 1 ’ f AN Y1-ICiM ME-THOOS Parerneter na -1 t1 ta-i Netfrods Suspended Solids Total Residue Dried at l03—105c S.M. 208A* Volatile Suspended Solids Total Volatile and Fixed Residue at 550c S.M. 208E Total 1 Jeldahl Nitrogen Nitrogen (Organic) S.M. 42i BOD Oxygen Demand (Biochemical) S.M. 507 Total Phosphate Preliminary Digestion for T.P. S.M. 425c Stannous Chloride Method S.M. 425E COD Oxygen Demand (Chem.)” Ampule COD Method 26 ------- * (10) Standard Methods for the Examination of Water and Wastewater 14th EditIon, 1975 APHA—AWWA—WPCF. ** (II) OCEANOGRAPHY INTERNATIONAL CORP. E.P.A. approved Alternative Method Federal Register Vol. 43, No. 45, Tues., March 7, 1978. 5.2 F1e{d o11i ’ç ff ere So1+ds S rio-Ie-s 5.2. I uinp Sedlineirt amo1es Prior to each runoff event the level of sediment in the catchbasin sump was measured and then sampled. Samples were taken by means of a cross sectional scooping as depicted in Figure 12, to assure a representative sample. Each sediment sample so collected was then air dried, weighed and then a sieve analysis conducted. The sieve series employed was the following: TABLE 2 S1€ fE SE -IES 1 [ 1 E R StJt’W S€D-IMEWT At4ALYSIS Stai dard leve thnnber Size Opening - In 1 es 8 0.0937 2.36 6 0.0469 1.18 30 0.0234 0.600 50 0.0117 0.300 100 0.0059 0.150 200 0.0029 0.075 Pan Subsequent to the sieve analysis, each sieved fraction was fired to conduct a percent volatile analysis. All procedures followed the prior referenced Standard Methods”. 5.2.2 - lwIet Sti-elfler Satne-les Inlet strainers were fabricated and installed to assess their additional pollutant removal benefit on catchbasins. A typical inlet strainer is shown on Figure 13. The inlet strainers were constructed of United States standard number 8 mesh brass screening (0.0937 in., 2.36 mm), attached to an aluminum plate. Samples from the first four runoff events were collected without the use of inlet strainers. Subsequently, samples from three additional events were monitored using the inlet strainers. Two types of samples were collected from the strainers; I) accumulations occurring during the dry period between sampled events and 2) accumulatIons generated during the runoff events. 27 ------- Sump Sediment Inlet Strainer Samples Cr088 Sectional Scoop Sample + Air Dry + Sieve Analysis + Firing of each Sieve Fraction Figure 12. Diagram of sampling and sample handling—solids samples. Entire Contents put Into bucket I Air Dry Weigh Total Contents + Sample Splitting + Weigh + Firing of Representative Sample N) OD Runoff Samples I ------- Strainer bag insert Figure 13. Photographs of inlet strainer unit. ‘ .0 I Typical dry weather collected debris ------- The field procedure was such that the Inlet strainer was left in place between events. Prior to an impending event, the Inlet strainer would be removed from the catchbasin and all contents put into a collection pail for transport to the laboratory. The inlet strainer would then be reinstalled Into the catchbaslfl for collection during the event Itself. Subsequent to the runoff event, the Inlet strainer would again be removed and all contents put Into a separate collection container for subsequent analysis. All samples so collected were then air dried, weighed and a representative fraction fired (same procedure as VSS analysis), to ascertain total mass collected and percent volatile. Figure 14 Is a photograph of debris collection in an Inlet strainer and collected debris in the laboratory. 5.3 O-tlier f -I el d De-terml ira H n s Monitoring of precipitation during a runoff event was conducted using an automated recording rain gage located adjacent to the site. Additional depth and velocity measurements were taken in the gutter during runoff events to provide additional flow data. 30 ------- Dry Weather debris collected Glenhaven 8.oad Baker Street Spring Street rn -u CA ) Wet weather debris collection Figure 14. Photographs of debris collection and collected debris from strainer bag. ------- CHAPTER 6 RESULTS QE fli.E CA-TCHBASIN MONITORING PROGRAM I ntr duct Ion A total of seven runoff events were monitored during the period of December 5, 1979 — January 4, 1980. The first four events were monitored without inlet strainers and, the last three with them in place. The following Chapter presents a summary of results of the catchbasin monitoring program. Section 6.1 presents a summary of results for all stations including chronology, sump sampling data and all water qual ity data collected. Section 6.2 presents the results of the sump sediment testing program. lnfluent strainer results are presented in Section 6.3 and finally Section 6.4 presents a review of findings. 6.1 Summary j Results—Liquid Samo-ies A chronology of the catchbasin monitoring program is shown in Table 3. As may be noted from the table, the total program extended from December 5, 1979 through January 29, 1980. During that period a total of nine runoff events occurred, of which seven were sampled, plus one minor snow melt occurring December 14—16. Tables 4—24 present all water quality data generated during the catchbasln monitoring program. Average flow rates for each of the measured runoff events are shown in Table 25. Two points of Interest may be generated from the table; I) the average flows measured tended to be somewhat lower than expected and 2) runoff to each catchbasin was proportional to catchment area. The first point of interest is most important In assessing the data presented in this chapter. Given the tributary areas and probability of various intensity events in the Boston area, runoff to the catchbasins in the order of 0.01— 0.12 cfs would be expected. All of the average flows measured were In the range of 0.013 — 0.05 cfs. Average runoff correlated reasonably with average rainfall. Lower flow rates would naturally yield less turbulence in the catchbaslfl and, ideally correspondingly higher removals. Table 26 Is a summary of the total computed mass and pollutant removals measured during the first four runoff events at each location. These data represent events without the use of inlet strainers. As may be noted from the data In the table, very high removals of solids ranging from 60—97% were evidenced. Correspondingly high removals were observed for VSS (48—97%), COO (10—56%) and BOD (54—88%). Although some negative removals were observed for all parameters except VSS, the overall solids 32 ------- TABLE 3. CHRONOLOGY OF CATQIBASIN MONITORING PROGRAM Date 12/5/79 Runoff event monitored Moderate intensity/short duration (Average Intensity = 0.09 in./h) 12/7/79 U I I U II (Average intensity 0.06 th./h) 12/12/79 “ II It It It I I (Average intensity — 0.08 in./h) 12/14/79 Snow Approximately one inch 12/14/79 Snow Melt 12/25/79 Runoff event Nighttime precipitation 0.33 in. cyclic periods of high intensity long .durat ion 12/27/79 Runoff event monitored Rain gage inoperative 12/28/79 Insert strainers instal—CAverage intensity 0.11 in./h) led/runoff event monitored 11 11/79 Runoff event monitored Late night storm high ntensity Insert strainers 0.49 inch rain — short duration installed (rain gage inoperative) 1/14/80 Runoff event monitored (Average intensity = 0.09 in./h) Insert strainers installed 1/29/80 Insert strainers removed 33 ------- TABLE 4. CATCItBASIN MONITORING DATA I LOCATION SPRING STREET I EVENT DATE 12/5/79 I _I ISAMPLE SAMPLING SOD COD TSS VSS TKN TP I TYPE TIME* I (minuteB) mg/I mg/I mg/I mg/i mg/i mg/i I I I IINFLUENT 0.0 — 730 10167.2 1382.2 5.0 0.48 I I 0.5 132 665 4396.4 498.3 — 0.56 I I 1.0 72 370 2085.7 170.8 5.6 0.32 I I 1.5 52 235 1805.4 167.8 — 0 .18 I I 2.0 42 185 1320.0 130.9 — 0.17 I I 2.5 27 210 1426.9 145.8 5.0 0.24 I I 9.0 11 45 798.2 57.1 2.1 0.08 I I 16.0 12 60 303.5 25.2 — 0.10 I I 17.0 17 55 267.8 27.7 — 0.05 I I 18.0 12 25 491.4 57.7 — 0.09 I I 19.0 — 10 465.9 63.7 — — I IEFFLUENT 16.0 122 235 1097.7 241.1 7.4 0.37 I 17.0 112 130 1168.6 265.9 — 0.30 I I 18.0 — 180 578.1 87.7 — 0.24 I I 19.0 75 95 659.0 143.2 6.0 0.24 I I 20.0 57 155 369.2 51.7 — 0.17 21.0 62 130 606.4 55.1 — 0.18 IPRE—SUMP — 130 1097.7 241.1 — 0.12 IPOST-SUMP — - — — — — * Time since start of storm ------- TABLE 5. CATCHBASIN LOCATION MONITORING BAKER STREET DATA I I EVENT DATE 12/5/79 I SAXPLE SAMPLING ROD COD TSS VSS TKN TP TYPE TIME* (minutes) mg/I mg/i mg/I mg/i mg/I mg/I INFLUENT 0.0 270 540 540 1146.5 1041.4 167.7 126.8 9.2 — 0.18 0.50 0.5 252 795.7 103.4 — 0.22 1.0 317 555 867.0 122.4 8.2 0.24 1.5 846.1 108.7 — 0.05 2.0 312 530 525 642.3 79.5 — 0.04 2.5 280 161.6 26.3 2.2 0.07 15.0 142 — 165 174.2 26.8 — 0.06 23.0 130 142.7 20.5 — 0.05 24.0 127 70 103.9 18.1 — 0.06 25.0 105 99.3 15.9 — 0.06 26.0 122 345 573.5 148.4 7.6 0.13 .EFFLUENT 23.0 335 348.0 76.2 — 0.14 I IPRE-SUMP 24.0 25.0 26.0 27.0 28.0 192 187 172 217 82 310 270 320 250 290 287.5 243.5 255.0 241.7 162.0 56.8 52.3 52.3 51.3 24.3 — 3.8 — — 7.6 0.18 0.12 0.14 0.14 0.09 IPOST-SUMP * Time since start of storm ------- (..) o TABLE 6. CATCHBASIN LOCATION EVENT DATE MONITORING DATA GLENNAVEN ROAD 12/5/79 I I ISAMPLE SA}IPLING BOD COD TSS VSS TKN TP I I TYPE TIME* I (minutes) mg/i mg/I mg/i mg/i mg/I mg/i INYLUENT 0.0 1075 1321.8 214.2 3.4 0.24 0.10 0.5 86 765 636.0 83.8 — 0.08 1.0 61 335 452.3 57.9 4.2 I 1.5 52 335 214.4 24.7 — 0.04 2.0 44 270 145.9 20.5 — 0.03 I 2.5 43 180 115.5 12.8 3.6 6.5 11 145 15.5 — — — 26.0 8 25 18.1 2.4 — — 27.0 8 130 10.1 1.3 — — — 28.0 7 180 7.0 — — I 29.0 8 85 9.8 2.3 — — IEFFLUENT 26.0 45 740 308.9 93.0 — 0.12 I 27.0 35 500 175.5 41.7 4.7 0.15 I 28.0 35 295 155.7 38.4 — 0.14 I 29.0 35 260 136.4 34.4 — 0.08 I 30.0 35 255 178.6 42.2 3.4 0.08 31.0 35 255 147.3 35.9 — 0.09 IPRE-SUMP 27 210 208.5 22.9 IPOST-SUMP — — — — — — * Time since start of storm ------- TABLE 7 . CATCHBASIN LOCATION EVENT DATE MONITORING DATA SPRING STREET 12/7/79 I SAMPLE SAMPLING BOD COD TSS VSS I TYPE TIME* (minutes) mg/i mg/i mg/i mg/i INFLUENT 0.0 5.0 10.0 15.0 20.0 25.0 150 17 22 9 13 9 530 180 70 70 70 130 510.0 394.9 264.5 198.8 235.7 182.5 76.7 44.0 27.3 21.7 21.1 21.4 I I I I I EFFLUENT 1.0 6.0 11.0 16.0 21.0 26.0 16 14 22 16 8 25 295 130 155 143 85 120 103.8 107.7 228.9 226.0 183.8 130.0 10.5 5.3 19.9 17.2 23.3 5.0 I IPRE-SUMP 20 80 77.9 — IPOST—SUMP 13 255 134.5 5.9 I I I * Time since start of storm ------- I TABLE 8. CATCHBASIN MONITORING DATA I I LOCATION BAKER STREET I I EVENT DATE 12/7/79 I I I I I I I ISAMPLE SAMPLING BOO COD TSS VSS I I TYPE TIME* I I I (minute8) mg/i mg/i mg/i mg/i I IINFLUENT 0.0 80 880 2409.4 164.6 I I 5.0 55 270 222.6 27.0 I I 10.0 13 80 771.0 43.2 I I 15.0 13 — 161.5 16.1 I I 20.0 4 25 342.1 26.4 I I 25.0 5 30 128.4 15.4 I IEFFLUENT 1.0 42 45 50.9 2.0 I I 6.0 42 155 70.8 — I I 11.0 45 130 62.8 — I I 16.0 20 285 65.1 1.0 I I 21.0 26 125 51.8 — I I 26.0 24 75 54.4 1.0 I IPRE-SUMP 20 55 4.5 6.2 I IPOST-SUMP 21 — 54.5 — I I I I I ! I I I I (.) * Time since start of storm ------- I I I TABLE 9. CATCHBASIN MONITORING DATA I I LOCATION CLEN1JAVEN ROAD I I EVENT DATE 12/7/79 I I I ISAMPLE SAMPLING BOB COD TSS VSS I TYPE TIME* I (mLnuteo) mg/i mg/i mg/i mg/i IINFLUENT 0.0 76 380 1075.7 267.6 I 5.0 33 195 220.5 35.3 I 10.0 35 80 109.1 16.8 I 15.0 32 60 85.9 12.9 I 20.0 32 — 83.4 12.3 I 25.0 39 25 65.5 9.8 IEFFLUENT 2.0 82 235 106.6 10.7 I 7.0 72 155 118.3 14.1 I 12.0 75 — 159.0 37.4 I 17.0 76 260 101.8 7.6 I 22.0 75 105 167.7 19.1 I 27.0 66 70 164.6 17.3 IPRE-SUMP 39 215 — — IPOST-SUMP 83 290 84.9 7.1 * Time since start of storm ------- I TABLE 10. CATCHBASIN MONITORING DATA I LOCATION SPRING STREET EVENT DATE 12/12/79 ISAMPLE SA}IPLING BOD COD TSS VSS I TYPE TIME* (minutes) mg/i mg/I mg/i mg/i INFLUENT 0.0 270 918 20017.2 6422.1 10.0 75 118 305.4 79.0 20.0 23 70 207.3 36.2 I 30.0 19 60 187.6 15.3 I 40.0 16 70 145.7 30.1 I 50.0 8 50 114.9 31.3 IEFFLUENT 2.0 18 215 746.4 398.1 I 12.0 8 165 201.0 52.7 22.0 4 143 260.9 70.6 32.0 2 143 214.7 58.7 42.0 10 95 156.9 41.6 52.0 4 70 101.5 30.1 IPRE-SUMP 20 — 32.7 15.7 IPOST—SUMP 36 50 99.0 28.7 * Time since start of storm ------- -J TABLE 11. CATCIIBASIN LOCATION EVENT DATE MONITORING DATA BAKER STREET 12/12/79 I I I • 1 I I SAMPLE SAMPLING BOD COD TSS VSS I TYPE TIME * (mlnute8) mg/i mg/i mg/i mg/i INFLUENT 0.0 220 580 4399.8 2939.5 10.0 20 130 346.7 45.8 I 20.0 16 50 277.2 135.3 I 30.0 5 70 166.7 35.8 I 40.0 20 35 152.3 28.1 I 50.0 28 25 110.7 27.7 IEFFLUENT 2.0 12 60 132.9 43.1 I 12.0 19 178 120.3 42.5 I 22.0 15 143 77.9 30.3 I 32.0 13 70 58.3 20.3 42.0 11 12 58.6 22.9 52.0 5 12 48.1 21.1 PRE-SUMP 32 53 71.2 50.0 POST-SUMP 28 60 49.9 21.2 * Time since start of storm ------- I I TABLE 12. CATCIIBASIN MONITORING CLENIIAVEN ROAD I LOCATION 12/12/79 I EVENT DATE SA)4PLE SAMPLING BOB COD TSS VSS I I TYPE T IME* I I (minutea) mg/i mg/i mg/I mg/i I I I 1403.9 IINFLUENT 0.0 90 260 1814.1 207.0 I 10.0 63 50 277.3 58.9 I 20.0 50 60 111.2 33.1 I 30.0 48 35 73.1 24.1 I 40.0 60 12 54.9 I I 50.0 58 12 94.9 57.2 181.5 EFFLUENT 3.0 40 480 617.3 120.9 13.0 44 238 401.3 23.0 31 190 238.0 33.0 19 143 146.3 I 43.0 5 118 104.9 I 53.0 11 60 76.4 IPRE-SUMP 24 70 89.6 46.2 27.6 I IPOST-SUMP 92 125 70.8 I I I I I I I I I ’) * Time since start of storm ------- TABLE I I 13. CATCHBASIN MONITORING DATA LOCATION SPRING STREET EVENT DATE 12/27/79 ISAMPLE SAMPLING COD TSS VSS I I TYPE TIME * I (minutes) mg/i mg/i mg/i I INFLUENT 0.0 755 14299.2 4726.2 1.0 580 1905.2 275.5 5.0 310 791.7 169.6 10.0 115 624.0 91.5 15.0 83 490.6 88.4 30.0 103 287.5 78.9 I I 45.0 103 234.9 97.1 60.0 — 585.2 101.5 IEFFLUENT 2.0 320 150.6 58.3 I I 15.0 335 142.8 53.9 I 30.0 215 58.8 18.0 I 45.0 125 87.2 27.4 I I 60.0 110 95.3 20.0 IPRE—SUMP 103 — — I I IPOST-SUMP 130 — I I I I I * Time since start of storm ------- I TABLE 14. CATCUBASIN MONITORING DATA LOCATION BAKER STREET EVENT DATE 12/27/79 SAMPLE SAMPLING COD TSS VSS I ITYPE TIME* I (minutes) mg/I mg/i mg/I I INFLUENT 0.0 355 4378.5 776.6 1.0 215 941.9 282.4 5.0 — 232.8 57.1 I 10.0 — 165.5 48.3 I 15.0 90 142.1 31.5 I 30.0 35 129.1 28.3 I 45.0 30 — — I 60.0 70 — — IEFFLUENT 1.0 170 409.8 137.6 15.0 140 346.0 86.6 30.0 75 195.0 44.4 45.0 70 112.2 26.7 60.0 30 88.8 23.0 PRE-SUMP 30 — — POST-SUMP 70 — — * Time since start of storm ------- TABLE 15. CATCHBASIN LOCATION C EVENT DATE MONITORING DATA LENHAVEN ROAD 12/27/79 ISANPLE SAMPLING COD TSS VSS I TYPE TIME* I (minutes) mg/i mg/i mg/i INFLUENT 0.0 440 2887.4 2245.8 1.0 220 357.8 171.6 5.0 30 431.8 339.4 I 10.0 65 113.3 42.5 15.0 60 41.7 26.2 30.0 30 48.2 25.5 45.0 40 68.8 36.4 60.0 — 50.3 20.5 IEFFLUENT 1.0 20 98.9 75.3 I 15.0 420 680.2 198.5 I 30.0 120 192.1 65.1 I 45.0 110 87.3 32.0 I 60.0 70 47.4 15.0 IPRE-SUMP 65 — — IPOST-SUMP — — — 01 * Time since start of storm ------- TABLE 16. CATC1IBASIN MONITORING LOCATION SPRING STRE EVENT DATE 12/28/79 DATA I ET . ISAMPLE SAI(PLING COD TSS VSS I I I TYPE TIME* I (minuteB) mg/i mg/i mg/i IINFLUENT 0.0 430 267.2 143.6 I 48.5 I I 1.0 155 184.7 I I 5.0 156 64.8 25.0 I 10.0 110 132.2 I 15.0 106 23.2 — I 20.0 120 143.5 115.1 I 30.0 155 230.2 73.3 I 40.0 130 253.3 101.2 I I 50.0 107 142.4 30.9 I IEFFLUENT 1.0 1073 819.3 100.4 I I 15.0 118 1006.9 I I 30.0 120 1144.4 I I 45.0 96 533.4 I I 60.0 73 447.1 46.7 I I 75.0 98 2350.0 109.8 I IPRE-SUMP - - - I IPOST—SUMP — - — * Time since start of storm ------- CATCWASIN MONITORING DATA LOCATION BAKER STREET EVENT DATE 12/28/79 I TABLE 17. SAMPLE TYPE SAMPLING fl * (minutes) COD mg/i TSS mg/i VSS mg/i INFLUENT 0.0 370 1574.9 1113.3 1.0 346 1202.8 730.3 5.0 188 591.2 128.2 10.0 170 759.8 134.5 15.0 156 285.8 107.3 20.0 93 477.3 80.8 I 30.0 118 168.0 62.1 I 40.0 118 206.9 52.0 I 50.0 80 235.5 90.8 EFFLUENT 1.0 163 118.9 69.3 I 15.0 123 92.0 29.7 I 30.0 78 82.8 43.8 I 45.0 73 54.6 31.3 I 60.0 70 82.8 43.4 I 75.0 63 67.9 33.5 IPRE-SUMP - — IPOST-SUMP - 64.7 29.7 * Time since start of storm ------- TABLE 18. CATCIIBASIN MONITORING DATA I LOCATION CLENHAVEN ROAD I EVENT DATE 12/28/79 I ISAMPLE SAMPLING COD TSS VSS I TYPE TIME * (minutes) mg/i mg/i mg/i I INFLUENT 0.0 258. 6167.3 4245.2 1.0 170. 343.7 67.0 I 5.0 — — — I 10.0 — — — 15.0 70. 45.7 14.6 I 20.0 45. 18.1 5.8 I 30.0 49. 57.7 19.7 I 40.0 — — — I 50.0 2. 51.2 13.5 I EFFLUENT 1.0 131. 164.1 55.1 I 15.0 95. 110.3 35.8 I 30.0 58. 79.6 31.7 I 45.0 25. 60.9 32.5 60.0 35. 50.9 28.1 I 75.0 18. 34.4 16.7 I PRE-SUMP — 14.6 12.0 I POST-SIJMP — 55.3 27.1 I * Time since start of storm ------- I TABLE 19. CATCIBASIN MONITORING DATA I I LOCATION SPRING STREET I I EVENT DATE 1/11/80 I SAMPLE SAMPLING BOD COD TSS VSS I TYPE TIME * I I (minutes) mg/i mg/i mg/i mg/i I I I I I IINFLUENT 0.0 225 968 31558.5 8211.8 I I 2.0 70 757 5044.8 723.1 I I 10.0 11 238 1808.1 153.0 I 20.0 22 238 3292.2 177.5 30.0 5 95 351.8 52.1 40.0 5 118 256.2 46.1 EFFLUENT 2.0 65 730 569.4 247.0 10.0 33 213 217.7 65.3 20.0 80 382 89.5 49.9 I 30.0 43 213 74.5 40.7 I 40.0 38 118 52.8 37.6 I 50.0 21 118 98.8 49.0 IPRE-SUMP 7 48 15.9 4.9 IPOST—SUMP 16 — 115.2 28.1 I ‘.0 * Time since start of storm ------- U, I I TABLE 20. CATC1U3ASIN MONITORING DATA I LOCATION BAKER STREET I EVE1IT DATE 1/11/80 I ISAMPLE SAMPLING BOD COD TSS VSS I TYPE TIME* I I (minutes) mg/i mg/i mg/i mg/i I I IINFLUENT 0.0 110 863 32250.2 10497.5 I I 2.0 60 843 3675.1 1173.8 I I 10.0 16 260 591.8 144.4 I I 20.0 14 190 598.8 145.4 I I 30.0 4 143 497.9 100.3 I I 40.0 3 118 341.9 71.8 I IEFFLUENT 2.0 33 333 326.5 118.8 I I 10.0 35 260 259.8 91.0 I I 20.0 27 188 170.5 61.1 I 30.0 26 167 60.3 47.9 I 40.0 22 118 76.3 28.9 I 50.0 24 118 74.3 26.5 IPRE-SUMP 26 70 3.2 1.2 IPOST-SUMP 7 143 129.4 42.4 I I * Time since start of storm ------- C . ,’ TABLE 21. I I CATCRBASIN MONITORING LOCATION CLENIIAVEN EVENT DATE 1/11/80 DATA I ROAD SAMPLE SAMPLING SOD COD TSS VSS I I I TYPE TIME* (minutes) mg/I mg/i mg/i mg/i PRE-SUMP 0.0 2.0 10.0 61 48 19 757 10550.1 260 429.0 238 182.7 8210.6 I 170.0 I 56.4 I 20.0 30.0 40.0 25 10 9 95 133.1 95 127.9 70 96.5 50.2 39.9 36.0 EFFLUENT 1.0 10.0 20.0 30.0 63 62 26 21 188 217.5 238 274.3 167 307.9 118 122.5 86.5 I 64.4 32.4 I 40.0 18 — 236.4 146.9 I 50.0 18 70 93.9 I IPRE—SUMP 27 118 36.6 IPOST—SUMP 22 358 141.6 44.9 * Time since start of storm ------- TAflLE 22. CATCIIBASIN MONITORING DATA I LOCATION SPRING STREET I EVENT DATE 1/14/80 I I ISAMPLE SAMPLING COD TSS VSS TEN T-PHOS I TYPE TIME* I (mlnute8) mg/i mg/i mg/i mg/i mg/i INFLUENT 0.0 885 16251.9 4537.7 14.0 13.60 I 10.0 155 546.0 128.0 2.2 9.10 20.0 107 118.2 29.3 — 8.00 I 30.0 70 143.0 26.6 1.2 1.30 40.0 53 73.1 21.0 — 4.40 50.0 48 86.5 23.4 1.5 6.40 EFFLUENT 1.0 166 273.4 66.9 1.9 12.50 10.0 115 205.9 49.5 1.9 5.00 20.0 45 127.5 30.4 1.5 4.20 30.0 97 92.9 24.4 1.9 8.10 40.0 53 85.1 23.2 — 4.00 50.0 45 59.5 23.2 1.4 3.90 IPRE—SUMP 107 52.1 14.1 1.2 6.30 IPOST—SUMP 95 51.8 13.3 1.1 — (7 1 F’) —I * Time since start of storm ------- I I I TABLE 23. CATCUBASIN MONITORING DATA I LOCATION BAKER STREET I EVENT DATE 1/14/80 I SAMPLE SAMPLING COD TSS VSS TEN T-PHOS TYPE TIME* I (mlnute8) mg/I mg/i mg/i mg/i mg/I IINFLUENT 0.0 578 2364.6 765.3 7.8 7.00 I I 10.0 143 259.0 109.2 1.7 5.20 20.0 115 192.7 32.4 — 5.10 30.0 93 142.9 34.7 1.6 5.10 40.0 118 119.9 19.7 — 3.80 50.0 — 78.6 41.7 — — EFFLUENT 1.0 215 83.2 28.9 1.8 — 10.0 190 80.0 26.2 2.2 — 20.0 137 70.4 26.1 1.9 8.10 30.0 170 56.1 21.1 1.4 2.50 40.0 155 60.3 23.8 — 2.80 I 50.0 118 208.3 68.9 2.1 1.40 IPRE—sUKP 107 27.6 11.6 1.5 2.60 POST-SUMP 188 247.9 82.4 3.0 — (71 (.1 * Time since start of storm ------- I I I TABLE 24. CATCHBASIN MONITORING DATA I LOCATION CLENHAVEN ROAD I EVENT DATE 1/14/80 I I I I I I I ISAMPLE SAMPLING COD TSS VSS TKN T-PHOS TYPE TIME * (minuteB) mg/i mg/i mg/i mg/i mg/i INPLUENT 0.0 668. 13445.3 8424.8 11.3 — 10.0 200. 660.9 104.9 3.7 5.70 I 20.0 170. 129.0 45.5 — 7.30 I 30.0 162. 98.5 35.7 2.6 — I 40.0 137. 81.9 30.6 — 9.50 I 50.0 123. 89.6 38.4 — 8.10 I IEFFLUENT 1.0 395. 260.0 81.0 7.0 2.80 I I 10.0 188. 385.9 117.7 5.1 8.20 I I 20.0 223. 3.8 219.1 72.5 6.30 I I 30.0 190. 2.9 145.5 54.2 9.60 I I 40.0 123. — 111.3 41.6 10.30 I I 50.0 155. 2.4 106.5 38.4 6.30 I IPRE-SUMP 73. 1.8 27.8 12.9 5.50 I IPOST-SUMP I * Time since start of storm ------- TABLE 25. AVERAGE FLOW RATES FOR RUNOFF EVENTS MONITORED Runoff Event Date SPRING ST. BAKER ST. GLENIIAVEN RD. (Flow Rates in cfs) 12/5/89 0.050 0.025 0.008 12/7/79 0.037 0.022 0.017 12/12/79 0.039 0.018 0.014 12/27/79 0.045 0.027 0.023 12/28/79 0.045 0.015 0.012 1/11/80 0.047 0.023 0.022 1/14/80 0.047 0.022 0.030 55 ------- tilt T CTPAINFRC TABLE 26.MASS AND PERCENT REMOVALS WITHOUT C 0* (* F 6* H I 12/05/79 38120 6309 83 4 4419 360 91 8 3872 394 89 8 12/07/79 2780 3040 —9 4 330 126 61 8 1630 1450 10 9 12/12/79 70072 5615 91 9 22092 2177 90 1 4296 2776 35 3 12/27/79 88356 2376 97 3 25876 789 96 9 7065 4911 30 5 12/05/19 6657 414 93 8 903 93 89 1 4408 55 98 8 12/07/79 3820 336 91 2 2780 827 70 5 1260 700 44 4 12/12/79 8353 760 90.9 4920 276 94 4 1363 727 46 6 12/27/79 8304 3140 62 2 1697 868 48 8 3050 1322 56 4 12/05/79 6 83 75 5 -10 5 71 20 88 5 1340 172 87 2 12/07/79 1863 581 68 8 252 75 70 2 556 734 -32 0 12/12/79 2823 2891 —2 4 2076 574 72 4 443 1430 —22 2 11/27/79 9540 2594 72 8 6936 905 87 0 2159 1736 19.6 U i TARIF 27. MASS AND PERCENT mFM0V*lc WITH INLET STRAINERS * All mass units are In grams Column Reference A TSS Influent H IF Influent B ISS Effluent N TP Fffluent C S Removal 0 0 Removal o yss Influent E 755 Effluent F S Removal Spring Street Baker Street Glenhaven Road 579 222 343 157 1373 154 2550 250 161 188 473 115 344 1511 175 317 436 177 L 61 7 54 2 888 90 0 -16 7 7 7 - 339 -81 1 59 4 M N ’ 3484 640 1692 181 218 45 0 81 6 893 79 4 12/28/79 01/11/80 0 1/14/80 12/28/79 01/11/80 01/14/80 12/28/79 01/11/80 01 / 14/80 Spring Street 5498* — 135723 69333 Baker Street 6811 - 59328 — 5901 Glenhaven Rd 7338 — 17536 21109 35570’ 4245 3332 922 1815 1012 762 2336 1204 96 9 95 2 86 6 96 9 82 7 89 6 86 7 95 0 28 88 2 * 30036 19190 3111 18965 1875 4596 13036 16222 3064 1684 859 464 702 357 305 811 5402 89 4 93 8 95 5 85 1 96 3 81 0 93 4 93 8 68 9 TEN TEN S TP TP S 5603*8908*_58 9 -* -* lnf.Eff Remov lnf Eff Remov 7743 6823 11 9 1084 1078 0 6 88 40 54 5 172 148 13 9 5307 2056 61 3 2041 1053 48 6 3778 2221 41 2 324 313 3 4 14 20 —42 9 39 17 56 4 2067 1804 12 7 885 561 366 2306 1632 29 2 262 388 —48 1 32 546 -16 0 79 109 -38 0 2729 2333 14 5 S COD Influent H COD Effluent I S Removal J ROD Influent K BOO Effluent S Removal ------- related pollutant removals due to the catchbaslns were extremely high. Although not measured, it Is uni Ikely that the overall removal efficiencies of the catchbasins would drop to low levels at higher flow rates. Table 27 presents similar results as Table 26 for the events monitored with inlet strainers. The net effect of the inlet strainers was a removal efficiency improvement of I— 10% percent.Nutrient data collected indicated no realizable treatment gain. Figures 15—lB present typical plots of the catchbasln data. The plots Illustrate three important findings; I) the influent characteristics to the catchbasins were surprisingly consistent over a series of events; 2) no significant effluent “first flush” was observed even though infiuent levels rose dramatically; and 3) effluent concentrations yielded an almost immediate baseline which the influent gradually tapered to meet. 6.2 . j Resu-1ts-Sum SedIm n± As noted in Chapter 5, suinp sediment quality and level was monitored prior to each measured runoff event. Figures 19—21 present composite sieve analyses results for Spring Street, Baker Street and Glenhaven Road, respectiveiy. Comparison of these data to other samples collected throughout the United States yields very comparable results. The results of firing each sieved fraction separately, are shown as a residual sieve analysis on the bottom of each figure. The difference between the two curves represents the percent volatile material present in the samples. In all cases, the percent volatile organic matter found was very high for all fractions, averaging approximately 70%. Table 28 presents the monitoring results of sedIment in the catchbasin sumps over the two month evaluation period. As a means of roughly cross—checking the monitoring data, the approximate Increase In mass in the sump was compared to the total measured amount deposited in the sump during the runoff events. Assuming that the sump materials have a specific gravity of 1.4, indicative of the mix of sand and organics found, computed accumulations of solids were 111, 117 and 39kg for Spring Street, Baker Street and, Gienhaven Road, respectively. With the exception of Spring Street, these results compare reasonably with the 349, 91, and 56 kg, respectively, deposited during the monitored runoff events (cumulated from Table 27). Although it is difficult due to the limited data set avai iabie to predIct the exact dry weather additional accumulated load, some dry weather load would have to be added to these numbers. The phenomenon of dry weather accumulation is discussed in more detail in the next section. Even with the addition of a miminal dry weather load there is reasonable comparability between the 57 ------- 4000 TIME0 315585mg/I TIME I mmite 5044 7mg/I SPRING STREET C a, 0 C 0 0 0 0 0 I— C), 0:, 3000 2000 1000 0 / TI 79 0 IS 30 Time (minutes) 1/11/80 Figure 15. Typical plots of Total Solids influent/effluent concentrations. 45 60 LEGEND Influent Effluent — — ------- 4000 TIME 0 32,250 mg/I E C 0 C 0 U 0 0 0 I- 3000 2000 1000 0 TIme (minutes) Figure 16. Typical plots of TSS influcnt/effluent concentrations. LEGEND Influent Effluent — — BAKER STREET U, 0 I / II / 80 12 / 7/79 IS 45 ------- GLENHAVEN ROAD D Time (minutes) Figure 17. Typical p]ots of COD Influent/effluent concentrations. LEGEND Influent Effluent — — ------- 350 C) 0 300 250 200 250 100 50 0 Time (minutes) Figure 18. Typical plots of BOL) influenh/effluent Loncentrations. BAKER STREET 12/7/79 LEGEND Influent L tluent — — 0 30 45 ------- U.S. Standard Sieve Numbers 100 90 80 70 60 w 50 c 40 U- 30 20 I0 0 Grain Size in mm Figure 19. Composite plot of sediment analysis for Spring Street. 16 20 30 40 50 70 tOO 140 4 2 I 0.6 0.4 0.2 0.1 0.075 LEGEND Sediment Fractions Tss Solids remaining of fer firing 62 ------- U.S. Standard Sieve Numbers .0 L I- Grain Size in mm Figure 20. Composite plot of sediment analysis for Baker Street 4 6 810 16 20 30 40 50 70 100 140 200 100 90 80 70 60 50 40 30 20 I0 0 - -..----v ‘ \ . _ - — —.-—-—- h b1 ç .:s __ ki 1 4 2 I 0.6 0.4 0.2 0.1 0.075 LEGEND Sediment Fractions TSS Solids remaining after firing 63 ------- l00 90 80 70 60 30 20 I0 0 Figure 21. Composite plot of sediment analysis for Glenhaven Road. U.S. Standard Sieve Numbers 4 6 8 tO 16 20 30 40 50 70 4 2 I 0.6 0.4 0.2 0.1 0.075 Grain Size in mm — — - LEGEND Sediment Fractions Tss Solids remaining after firing 64 ------- accumulations measured in the sump and, the sum of residuals from the runoff events. This data further corroborates the monitored evidence Indicating catchbasin performance to be very high. TABLE 28 MONI-TOR-ING QE SUMP I.EVELS IN CATCHBASINS Level’ Level’ Level’ Spring St. Baker St. Glenhaven Rd. (Inches) (Inches) (inches) 12/5 — 74 70 12/7 70 75 69 12/12 68 ii 66 12/27 68 71.25 68.50 2/28 68 71 68 I/lI 67.25 71 72 1/14 66.30 71.50 69.50 1/29 66.50 71.50 69.50 Overall increase (Inches) 3.5 2.5 0.5 *lndicates Istance to sediment from ca*chbasln rim In inches 6.3 Summary f Results—Influent Strainer-s As noted in Chapter 5, inlet strainers were specially designed, constructed and installed in each of the three monitored catchbaslns during the last three storm events. As Indicated In Table 3, the influent strainers were Instal led Just prior to the runoff event occurring on 12/28/79 and maintained for two weeks subsequent to the final monitored event (until 1/19/80) to give additional data on dry weather accumulations. Table 29 presents a summary of the influent strainer data. Data shown includes; accumulation period (if dry weather), total dry mass of solids collected and percent organic. The inlet strainers collected substantial amounts of materIals durIng dry weather. As may be noted from the data, Spring Street exhibited continuously higher accumulation rates than Baker Street and Gienhaven Road, with significantly more of the matter collected inorg8fliC sand and dirt. This would be indicative of greater wash—off soils loadings from the open areas along Spring Street as well as the much greater traffic density on Spring Street, being a major local commuter road, versus the other two sites 65 ------- TABLE 29. RESULTS OF THE INFLUENT STRAINER STUDIES Total Dry Mass Collected — grams Percent Volatile Date A B C D E F G H I. Wet Weather Accumulation (During Event) 12/28/79 X 1293 5.5 12.2 17.0 68.2 74.3 1/11/80 X 984 556.7 56.7 16.8 34.2 52.3 1/14/80 X 159 214.8 53.8 24.6 60.8 74.4 II.Dry Weather Accumulations (Between Events) 1/11/80 14 3311 387 102.7 34.2 65.8 70.4 1/14/80* 2 3246 245 718.7 22.9 57.8 71.8 1/29/80 15 1758 539 194.0 24.0 54.2 76.2 Legend A — Antecedent dry period days B — Runoff event C — Spring Street D — Baker Street E - Glenbaven Road F — Spring Street C — Baker Street H - Glenhaven Road * Heavy accumulations due to high intensity short duration storm evening of 1/11/80 0.49 inches rain. 66 ------- being primarily residential. The major fraction of collected materials from Baker Street and Glenhaven Road was organic leaves and decomposing lawn clippings, as exhibited by the high organic content. Pollutant removal of the influent strainers during storm events was small in relation to that removed in the sump during the same event, ranging from two to ten %. During dry weather significant accumulations were observed in the inlet strainers, but these accumulations by weight were small In relation to the mass removed in the sump during a storm event. Although, the design size of the inlet strainers used in this program was set at an initial number 8 mesh, (0.0937 in. 2.36mm) this size could have been reduced to gain greater removals. Even so, It Is unlikely that the overall efficiency of the units would be great enough to warrant their wide spread use. The reasons for this conclusion are twofold. First, the Inlet strainers detain large amounts of materials, forming a filter cake of progressively finer opening as deposition occurs. This phenomenon would lead to rapid clogging and subsequent localized flooding due to blockages of the catchbasln inlets. It is estimated that required maintenance frequency of the inlet strainers would be weekly making overall maintalnenCe costs high. Secondly, detained materials in the inlet strainers are subject to decomposItion between storms as are materials In the catchbasin sump. Unlike the catchbasin sump, the materials in the inlet strainers are held above the overflow outlet making them available for dischage during the next runoff. Organics entrained in the Inlet strainers would tend to break down to fine settleable and colloidal particles unsuitable for removal by the catchbasin sump. In contrast, decomposing materials in the catchbasin sump would tend to migrate into the pores between the grit particles. The overall result of a poorly maintained inlet filter, (over one week in cleaning interval) could be local flooding and increased pollutant discharge to the receiving sewer due to build up and decomposition in the strainer. 6.4 RevIew t Catc-hfraslfl f4011-itor-ln9 Data The catchbasin monitoring program collected a large amount of simultaneous performance data on three test catch— basins in the West Roxbury section of Boston. The catchbasins were divided into two types, direct discharges from the gutter Into the receiving sump and discharge to a transmission sump prior to the receiving sump. The latter type, as shown by the Spring Street catchbasin, offers seemingly better energy and thus turbulence dissipation. However, this could not be verified by the performance data, In that removals from all three catchbasins were comparable. 67 ------- The effects of higher traffic density were dramatically Illustrated in the very high influent levels monitored on Spring Street, relative to the other two sites. This effect was Illustrated during both dry weather, where significant deposition occurred and, during runoff. See study by Saheen. Initially, pre—sumP samples indicated moderate pollutant levels. In almost every case initial effluent concentration levels were less than the measured pre—sump sample, even though the influent concentrations rose dramaticaily at the same time yielding no significant “first flush” effects. Overall sol Ids related pollutant removals were generally quite high with few exceptions, although periodic negative removals or fiushout were observed for all parameters except VSS. Catchbasin removals for nutrients generally were negligible to negative, indicative of the transfer of nutrients from being bound in sol ids in the sump to dissolved, after decomposition in the sump. Sediment accumulation analysis indicated that the materials deposited in the sump at a rate such that cleaning every six months to one year, dependent on conditions, would maintain observed pollutant removals. Analyses of the sump sediments yielded data consistent with that generated in other cities. No appreciable difference was observed in the sediment characteristics between the initial sample (old material left as residual of cleaning operations) and those collected after significant fresh deposition. inlet strainers collected substantial amounts of dry weather and runoff Induced solids, but their overall effectiveness and potential for widespread utilization was deemed limited by high maintenance requirements vs. limited pollutant removal gains. 68 ------- CHAPTER 7 CATCHBASIN CLEANING COSTS IN CITY OF BOSTON 7 • I Fore,ror In this chapter excerpts from an analysis conducted on the City of Boston sewer system for the Boston Water & Sewer Comm i ss ion (BW&SC) by EDP are presented (12). Avernga maintenance costs for cleaning of catchbaslns (based on present operating data) are presented in section 7.2. The costs generated were then compared to data for other cities of similar size end weather conditions in section 7.3. In section 7.4 the relative economics of increased catchbesin cleaning frequency are assessed using Boston data for combined sewer systems. 7.2 Büst’on Ca-f’c1ibe-s1i C1eeii1i Ces+s Cost estimates were generated for cleaning of catchbesiflS as presently being conducted by BW&SC crews. Costs were broken down into four categories: labor (including overhead), energy usage, vehicle and equipment maintenance, and finally, disposal costs. The break—down and total cost figures are sumarized in Table 30. Rates of catchbasln cleaning were obtained from the analysis of crew performance data supplied by BW&SC and through direct observation of cleaning operations by EDP personnel. After careful review of labor rates with the BW&SC financial division, labor costs were estimated at $8.83 per hour for catchbasin cleaners. These average figures include overtime and burdening factors. Under present conditions an average of 5.2 catchbasins are cleaned per man per day. The resulting labor cost is $13.60 per basin cleaned. This cost is a citywide overall average based on 1979 reported results and Includes travel and paid break—time. Energy costs are based on average vehicle fuel usage. Catchbasin cleaning trucks were determined to average 10 gallons per day based on BW&SC reported volume data. Fuel was estimated at $1.25 per gal Ion. Fuel costs could not be linked to miles traveled due to the large idling times and usage of fuel for operating cleaning machinery. Resulting energy costs were $2.40 per basin. Vehicle and equipment maintenance costs were more difficult to estimate. Maintenance costs were estimated to be proportional to vehicle fuel costs. A proportionality constant of 2 was determined by examining the expenditures for 1980. For 1980 69 ------- the following figures were determined for the entire 144 vehicle BW&SC fleet: Maintnenance $200,000 Insurance 75,000 Fuel 148.000 $423,000 Resulting maintenance costs are $4.80 per basin. Disposal costs can and do vary rapidly. In the fal I, 1980, the BW&SC was forced to change Its dump site. The new (temporary) site charges $15 per dump, regardless of the size of truck. An analysis of catchbesin dimensions of approximately 80 catchbasins representatively scattered throughout I-he BW&SC sewerage system indicated that the average sump and total volumes equal 2.4 and 3.6 cubic yards (1.83—2.75 cubic meters), respectively. Disposal costs range from $7.20 (sump f ii led) to $10.80 (entire basin tilled) per cleaned catchbasin using an average catchbasln cleaning truck volume of 5 cubic yards (3.81 cubic meters). As shown in Table 30, average Boston catchbasin cleaning costs range from $28.00 to $31.60. 7.3 Boston/National Catchbasln Cleaning Cost Comparison National catchbasin cleaning cost figures vary considerably. The average cost per basin, based on 17 communities with high snow falls, is $15.8 per basin with a standard deviation of $6.8 per basin (ENR = 3000)(I). Cleaning costs per basin ane expected to be higher as Boston catchbasin sumps (2.4 cubic yard or 1.83 cubic meters) are iarger than the national average sump volume (I) (1.7 cubic yards or 1.30 cubic meters). Based on 10 communitIes, a national average of $10.4 per cubic yard is reported with a standard deviation of $11.6 per cubic yard (1). For a typical Boston basin, the national average would predict $37 per basin to clean where the basin is full and $25 per basin to clean where only the sump is full. Similar estimated BW&SC costs (shown in Table 30) of $31.60 and $28.00 per basin are within the national averages for comparable situations and techniques. These costs reflect labor, energy, maintenance and dumping charges. No cost of capital investments are included. 70 ------- TABLE 30. PRESENT CATCHBASIN CLEANING COSTS (1980, ENR 3OOO, BOSTON) Based on Full Basin Volume Based on Full Sump Volume (97 ft 3 per basin) (65 ft 3 per basin) Labor 13.60 13.60 Energy 2.40 2.40 Vehicle & - Equ I pment MaIntenance 4.80 4.80 Disposal 10.80 7.20 Total S 3i.60 28.00 71 ------- Sect I on 7.4. £ mi Aji i siS i Ir i Cleaning Fre uenc in this section two typical scenarios are examined using Information generated from an analysis of catchbasin cleaning maintenance practices in the City of Boston (12). First, the issue of whether Increased catchbasin cleaning frequency in combined sewer systems is worth the benefits of decreased Waste— water Treatment Plant (WWTP) solids handling Is examined using a 162 acre (65.6 ha) test area in West Roxbury, Boston. Second, pollutant removal I cost effectiveness of increased catchbasin cleaning frequency practices versus in—line storage and swirl treatment technology is examined, in both cases an existing WWTP is assumed to exist with adequate solids handling capacity. Case Pertinent data used in this analysis are discussed in detai i elsewhere (12) and are summarized in Table 31. in that study an empirical catchbasln solids accumulation simulation model was developed and used to estimate solids retained In typical Boston catchbasins as a function of intervals between catchbasin cleaning and solids input during storm events. These results are summarized In Table 31. If solids are not removed by the catchbasins then the solids will increase both sewer cleaning and solids removal costs at the treatment plant. To address this problem catchbasln cleaning costs were estimated from the previously described BW&SC data for cleaning frequencies of 2, I and 1/2 years for the West Roxbury test area (85 basins). Present values were calculated for a twenty year planning period and a 6 1/8% annual discount rate. Present worth of these annual costs over the twenty year period for the West Roxbury test area are $15,200, $23,300 and $48,500 respectively for cleaning intervals of 2, 1 and 1/2 years. Storm sewer cleaning costs in the West Roxbury test area estimated for comparison with catchbasin cleaning costs. For the estimate it was assumed only lines 24 inches (61 cm) and larger would need to be cleaned. (1) Average cleaning of storm sewers in the entire system in the West Roxbury test area Is $18,500 (1980, ENR = 3000). Present values were calculated for the West Roxbury cleaning operation based on a cleaning frequency of every 10 years and every 5 years for the 20 year planning period and 6 1/8% discount rate. (1) The present worth of sewer cleaning once every ten years is $21,500 (1980, ENR3000). The present worth if cleaning is needed every 5 years is $42,900. 72 ------- TABLE 31. PERTINENT DATA — WEST ROXBURY, BOSTON TEST CASE Pertinent Data — West Roxbury, Boston Test Case A. Wtershe-d Chpra ter-isti s • Area 105 acre (42.7 ha) single family residential and 55 acre (22.41 ha) open space. • Runoff coefficient residential area = 0.45 • Curb/gutter density .097 miles/acre (0.38 km/ha) • No.catchbasins = 85 (1.24 basins/acre or 3.05 basi ns/ha) B. Catchbasln Dimensions ( Aver-age ) • Sump volume 64.8 ft 3 (1,84 m 3 ) • Total volume 97.2 ft 3 (2.75 m 3 ) • Total depth 7 ft (2.1 m) C. Catchbasin CIeriing Cost-s (Boston, 1980, ENR = 3000) • 2 year frequency — $31.60/cleaning (97 ft 3 removed)* • 1 year frequency — $26.25/cleaning (49 ft 3 removed) • 1/2 year frequency — $25.15/cleaning (39 ft 3 removed) • Assume solids density — 110 lb/ft 0. Storm Sewer Cienlng ( Test Are-a ) (Pipes exceeding 2 ft (0.6 m) diameter) • Footage = 4837 ft (1475 rn) • Average cleaning cost = $3.83/ft ($1.17/rn) (1980, ENR = 3000) E. WWTP Solids Hendliny Costs • Operational costs for thickening, vacuum filtration, disposal & maintenance: $193—$581/ton solids handled ($175.5 — $528.2/metric ton solids handled (Boston, 1980, ENR3000) * Determined from empirical catchbesin performance model (12) 73 ------- WWTP solids handling costs were included for comparison with solids removal through catchbasin cleaning. it was assumed that the WWTP solids handling capacity was adequate, that Is, solids loading changes caused by varying catchbasin cleaning policies would not require new facil ities. Only the operating costs would be increased by an increasing solids load. The greater Boston area presently has two major wastewater treatment plants. Plans are being implemented for facilities to reduce sludge volumes and prepare sludges for land disposal. Stormwater treatment plants have also been constructed such as the Cottage Farm facility and plans are being developed for major stormwater treatment facilities throughout the area including the BW&SC service area. Due to the dynamics of the system it was deemed appropriate to examine the range of sludge handling costs nationally in terms of establishing general operating policies for Boston. Costs indicated in Table 31 include pumping, line stabilization, In some cases thickening either by gravity or vacuum, transportation, disposal, and maintenance of the disposal facility. Costs are operational only; no construction costs are included. The cost range is for a city with 25,000 combined sewered acres. It was assumed that all solids captured by a catchbasin under a given cleaning policy would be captured by the WWTP under a less efficient catchbasin operating policy. Zero loss to overflows was assumed. In addition, ten percent of the removable solids escaping the catchbasifl were considered as deposition and removed by sewer cleaning. The WWTP sal ids handl ing costs for different catchbasin cleaning policies are presented in Table 32. Comparisons between cleaning frequencies and WWTP solids loadings were made for cetchbasin cleaning frequencies of 2,1 and 1/2 years. The results are presented in Table 33. The two year frequency would plan to clean relatively full basins. The 1 year frequency would only have suinp volumes to clear. The 1/2 year frequency would maintain the basins below the performance breakthrough curve at al I times. Cost estimates were made using both the low and high range WWTP solids handling figurQ. The effect of Increased sewer cleaning needs was simulated by assumIng a decrease in catchbasin cleaning frequency that would double the need to clean sewers. The “no sewer cleaning” assumption is also included. These results are also presented in Table 33. 74 ------- TABLE 32. WWTP SOLIDS HANDLING COSTS W. ROXBURY CASE EXAMPLE Catchbasin Annualized Annualized Annual WWTP Total Cleaning Weight Solids Weight Solids Solids Handling Present Frequency Removed per Arriving at Cost per Catch Value*** (years) Catchbasin WWTP per —basin Solids (lb)* Catchbasin** $193/ton—$581/ton $193/ton C lb) 2 5335 3485 $336.30 $1012.39 324.5—976.7 5390 3430 $331 .00 $ 996.42 319.3—961.3 1/2 8580 240 $ 23.16 $ 69.72 22.3— 67.3 * See part C Table 31; also total annual solids input per catchbasin 9800 lb. ** Note 10% of solids escaping catchbasin deposit In sewer lines *** 6 1/8%, 20 year planning period TABLE 33. COMPARATIVE ECONOMICS OF CATCHBASIN CLEANING FREQUENCY (BOSTON CONDITIONS, 1980, ENR=3000) West Roxbury Test Area, Data Present Value Costs* ($1000) Catchbasin Sewer Cleaning Cleaning Catchbasin Sewer SolIds Handling Total Frequency Frequency Cleaning Cleaning WWTP** (Years) (Years) 2 10 15.2 21.5 324.5 361.2 2 5 15.2 42.9 324.5 382.6 1 10 25.3 21.5 319.3 366.1 1/2 10 48.5 21.5 22.3 92.3 2 15.2 — 324.5 339.7 1 25.3 — 319.3 344.6 1/2 48.5 — 22.3 70.8 * 6 1/8% interest — 20 years planning period ** low solids handling rate used ($193/ton) *** no sewer cleaning assumed 75 ------- The results depicted in Table 33 indicate that bi- annual catchbasin cleaning in Boston is extremely cost— effective. These results are somewhat biased in that average catchbasin volumes in Boston are much higher than the national average (see Table 31). Case In the prior example no wet weather control of combined sewage other than WWTP control was considered. In this example overall solids removal costs of catchbasin cleaning are compared with the cost—effective results of a recently adopted (1981) CSO Facll ity Plan in Saginaw, Michigan (13). The new Facility Plan consists of extensive in—i i ne storage coupled with bleedback to a secondary WWTP with ample excess hydraulic and solids handling capacity and 5 maJor swirl solids separator Installations to treat overflows. Present worth cost (6 1/8% — 20 years) of the new in- line storage program and the operational cost of soi Ida handling at the City of Saginaw’s WWTP equals $2.26 million dollars. Annual elimination of wet weather related solids and SOD loadings attributable to this plan equal 2.89 mu lion lb (1.31 mil lion kg) and 0.777 mil lion lb (0.353 rnil lion kg), respectively. Overall present worth unit cost per pound solids and BOD removed equal $0.0391 and $0.145, respectively. Combined present worth costs of the in—line storage program, the five new swirl facil ities (less disinfection) and operational costs of aol ida handling at WWTP equal $12.08 million dollars. Annual wet weather related solids and BOD removed attributable to the combined plan equal 3.955 million lb (1.8 a 1111 on kg) and 0.907 mill Ion lb (0.412 million kg) respectively. Overall present worth unit cost per lb solids and BOD removed equal $0.1527 and $0.656, respectively. Costs for treating the detained combined sewage volume at the WWTP are not included in either set of these calcu I ati ons. Overal I present worth aol Ida removal unit costs for the 85 catchbasins in the West Roxbury test area equal S0.0669/lb removed, $0.0659/lb removed and $0.0046/lb removed for catchbasln cleaning frequencies of 2, I and 1/2 years, respectively.These unit costs reflect the combined program costs of catchbasin cleaning, sewer cleaning and WWTP solids handling given in Table 32. it is clear that the unit cost of solids removal attributable to a biannual catchbasin cleaning program Is extremely cost—effective in 76 ------- comparison to either the In—line storage or in—line storage / swirl solids separator treatment facilities. Similarly, the unit cost of BOO removal attributable to bi- annual catchbasin cleaning is cost effective in comparison to either In—line storage or in—line storage/swirl treatment assuming that the relative fraction of BOO to solids In materials removed from catchbaslns is as low as 4%. 77 ------- REFERENCES &L BIBLIOGRAPHY I. Lager, J.A., W. G. Smith and G. Tchobanoglous, “Catchbasin Technology Overview and Assessment.” USEPA Report No. EPA—600/2—77051, NTIS May, 1977. 2. Thomas, A.A., “Design Criteria for Storm Water Disposal,” Fourth Annual Sanitary and Water Resources Engineering Conference, June 4, 1965. 3. Foiwell, P.A., Sewerage , 8th ed., New York, Wiley, 928. 4. Babbitt, H.E., Sewerage Sewage Treatment , 6th ed., New York, Wiley, 1947. 5. Metcalf & Eddy, Inc., Wastewater Engineering: Collection Treatment D-isposai , New York, McGraw—Hill, 1972. 6. American Pubi Ic Works Association. Survey of Practice as to: Street Cleaning, Catchbasin Cleaning, Snow and Ice Control, March, 1973. 7. Mahan, R.D., “Flow Characteristics of a Catch Basin. M.S. Thesis, University of IllinoIs. 1949. 8. Water Pollution Aspects of Urban Runoff. American Public Works Association. USEPA Report No. IIO3DNSCI/69 (NTIS PB 25 532). January, 1969. 9. Sartor, J.D. and G.B. Boyd, Water Pollution Aspects of Street Surface Contaminants. USEPA Report No. EPA—R27208 1 (NTIS PB 214 408). November, 1972. 10. Standard Methods for the Examination of Water and Wastewater 14th Edition, 1975 APHA—AWWA—WPCF. 11. Oceanography international Corp. E.P.A. approved Alternative Method Federal Register Vol. 43, No. 45, TUOS., March 7, 1978. 12. Sewerage System Inspection Management Study. Environmental Design & Planning, Inc. Draft Final Report submitted to Boston Water & Sewer Commission, Boston, Mass. February, 1981. 13. Pisano, W.C. et al., “Facil ity Plan For the Control and Treatment of Combined Sewer Overflows to the Saginaw River.” U.S. EPA report. Great Lakes National Program Office, Cnicago, ill., March 1981. 78 ------- |