I JASON M.CORTELL AND ASSOCIATES INC. environmental consultants I and planners 244 SECOND AVENUE WALTHAM MASSACHUSETTS O2I54 I 617/890-3737 I I I I TECHNICAL MEMORANDUM Nutrient Control Alternatives; I at Lake Cochituate, Results of I Rapid Sand Filtration Pilot Test and! i High Gradient Magnetic Filtration Tests ' I Prepared for: I : MASSACHUSETTS DEPARTMENT OF ENVIRONMENTAL QUALITY -ENGINEERING I DIVISION OF WATER POLLUTION CONTROL I Prepared by: I JASON M. CORTELL and ASSOCIATES INC. I I I October 1980 I WALTHAM. MASSACHUSETTS • GLADSTONE, NEW JERSEY 1 Mi&ffifflu- 1 ANDASSOCIATES INC- • TABLE OF CONTENTS 1 Page 1.0 INTRODUCTION 1 2.0 NUTRIENT CONTROL ALTERNATIVES 4 1^H 2.1 Instream Nutrient Precipitation 5 2-2 In Situ Nutrient Removal from Fisk Pond . 5 I 2.3 Nutrient Removal from South Pond 6 2.4 Nutrient Reduction by Water Filtration Techniques 7 • 2.4.1 Nutrient Removal Through Rapid Sand Filtration 8 2.5 Chemical-Physical Water Treatment 9 1 2.6 Other Nutrient Control Alternatives 12 3.0 REQUIRED TREATMENT VOLUMES 16 4.0 COSTS FOR A HIGH GRADIENT MAGNETIC FILTRATION FACILITY (HGMF) 17 1 5.0 CONCLUSIONS AND RECOMMENDATIONS 19 REFERENCES 20 Attachment A 1 LIST OF FIGURES 1 Figure 1 Lake Cochituate Drainage Basin 2 1 Figure 2 Locus Map of the Lake Cochituate System 3 Figure 3 Flow Diagram of a 14 mgd HGMF Treatment Facility 14 LIST OF TABLES 1 Table 1 Analysis of Water at the Burlington Water Treatment Facility 9 Table 2 Removal of Phosphate from the Charles River Water 10 1 Table 3 Results of Chemically Assisted High Gradient Magnetic Filtration of Fisk Pond Water 11 Table 4 Relative Efficiencies of Sewage Treatment 1^H Operation and Process 13 1 Table 5 Comparison of Water Treatment Costs for CSO 18 1 ' I JASON M.CORTELL I AND ASSOCIATES INC. 1.0 INTRODUCTION I The Lake Cochituate restoration project incorporated four major areas of focus which include: I Water quantity and quality monitoring Public education Dredging of Snake Brook I Reduction of nutrients in the drainage basin and Lake Cochituate The monitoring of water quantity and quality has been conducted by the Massachusetts Division of Water Pollution Control and the United States I Geological Survey. A public education program has been conducted by the Lake Cochituate Watershed Association. Specifications and Plans have been prepared for the dredging of Snake Brook and that aspect of the Lake program I is currently entering the final stages of review before bids for the dredging are requested. Two reports have been completed which explore in detail a number of nutrient control alternatives which could be implemented. These reports I are: • Technical Memorandum - Condition and Estimated Effectiveness of the Pegan Brook Filter Beds. December 16, 1977. Massachusetts Department I of Environmental Quality Engineering, Division of Water Pollution Control, Boston, Massachusetts. I • Technical Memorandum - Nutrient Budgets for Fisk Pond and South Pond and the Impact of Nutrient Controls on the Waterbodies. August 3, 1978. Massachusetts Department of Environmental Quality Engineering, I Division of Water Pollution Control, Boston, Massachusetts. The purpose of this report is to further discuss control of nutrients and to present the findings of a pilot rapid sand filtration test for the removal of I algae and nutrients from Lake Cochituate. Figure 1 indicates the relationship of the various sections of the Lake Cochituate system and its drainage basin. Figure 2 is a locus map indicating the position of the various basins of the I Lake Cochituate system. I I I I I I -1- .AKE COCHITUATE DRAINAGE BASIN JASON M.CORTELL ANO ABSOC1ATEB fOC. Present Drainage Basin Boundary ^- Historic Drainage Basin Boundary Figure 1 Middle Pond Coding Pond | South Pond Peggj} Pegan Brook Fisk Pond LOCUS MAP OF THE LAKE COCHITUATE SYSTEM 0 Potential HGM Filtration Plant Sites JASON M.CORTELL ANO ASSOCIATES INC. Figure 2 I JASON M.CORTELL I AND ASSOCIATES INC. I 2.0 NUTRIENT CONTROL ALTERNATIVES Nutrient control alternatives which have been considered at Lake Cochituate and within its watershed include: 1 Point source controls Watershed management In-stream nutrient precipitation I Nutrient removal from Fisk Pond Nutrient removal from South Pond Use of Pegan Brook slow sand filters Intermittent sand filtration I Rapid sand filtration Full scale chemical - physical treatment I The Massachusetts Department of Environmental Quality Engineering (DEQE) is continuing efforts within the watershed to locate and control any point sources of nutrients to the tributary streams. The DEQE recently conducted I an intensive watershed sampling program under low volume dry weather flows. The survey, conducted on July 22, 1980, evaluated the quality of base flow water in the main stream of Beaver Brook (predominantly within the- Town of Framingham). The general nutrient and bacteriological I concentrations found in the July sampling are higher than typical urban runoff quality. The Boston Metropolitan District Commission is completing an infiltration-inflow analysis of the Framingham sewer system. Additional work I by Haley and Ward has also been conducted on the Farm Pond interceptor which passes through a large portion of the Lake Cochituate watershed. It is not the direct purpose of an I/I analysis to seek out cross connections within a I sewerage system, nor were any reported in the MDC study. The determination of the presence of any such cross connections or other illegal connections to the storm sewer system would involve a detailed storm sewer survey. The I sanitary and storm sewers within Framingham are separate systems. The watershed for Fisk Pond which includes Course Brook and Beaver Dam I Brook contains the following percentages of land usage: Urban 36% Forest 49% Agricultural 6% I Other 8% (land fills; borrow pits; cemeteries; recreational lands; open space; and I open marshes) While 49 percent of the drainage basin is forested, more than half of this is in the headwater areas of either Beaver Brook or Course Brook. The 36 percent I of urban lands are located along the two streams and the Lake itself. This proximity does not allow sufficient renovation of surface water before it reaches the Lake. Since the South Pond receives approximately 80 percent of its water from Fisk Pond and hence, the highly developed areas of I Framingham, watershed management is as necessary as the control of point I I -4- I JASON M CORTELL I AND ASSOCIATES INC. sources of pollution. However, it is also reasonable to expect that with the best efforts of watershed management in effect that non-point source pollution through urban runoff will continue to be a major contributor of I nutrients to the Lake and algae blooms will continue to be experienced. In consideration of the proximity of the industrial and urban centers of Framingham and Natick to receiving streams and Lake Cochituate, a I centralized water treatment facility is considered the most positive technique to improve water quality for Lake restoration. The following discussions provide a synopsis of assessments which have been I conducted on the Lake and provide a basis for comparisons in terms of cost* I effectiveness, and adverse environmental impacts. 2.1 Instream Nutrient Precipitation I The alternative of instream nutrient stripping was considered for the two major tributaries entering Fisk Pond. Beaver Dam Brook carries water from the urban and industrial area of Framingham as well as urban areas of portions of Natick. With the exception of some headwater sections, there are virtually I no natural areas remaining on Beaver Dam Brook. The second tributary considered is Course Brook which drains additional urban I and industrial areas of Framingham plus agricultural and urban areas of Sherborn and Natick. Instream nutrient removal in either stream alone would be insufficient for the removal of a sufficient amount of nutrients. Therefore, two separate chemical feed facilities are necessary and the total cost was I found to be approximately $65,000.00 capital expenditure and $70,000.00 annual operation and maintenance for each unit (in 1978 dollars). I A principle drawback with continual injection of coagulant to a natural stream without provisions for capture of the flocculant are the long-term impacts to biota in downstream areas and the settlement of the flocculant once it enters I Fisk Pond. Because extreme difficulties woul* d be encountered in dredging Fisk Pond for removal of the settled flocculant, the alternative to use I in-stream nutrient precipitation was not considered feasible. 2.2 In Situ Nutrient Removal from Fisk Pond I At the present time, Fisk Ponds acts as a large settling basin at the base of the Lake Cochituate chain, and to some degree also acts as a stabilization lagoon where nutrients are incorporated into biomass, principally in the form I of very dense blooms of blue-green algae. Removal of nutrients in Fisk Pond would involve an in situ application of a coagulant to precipitate the nutrients and algae. During the nutrient budget evaluations, it was found that Fisk Pond has a very fast flushing rate (less than one week in June) and if the I applications were to be conducted by boat they would have to be repeated I almost on a weekly basis. The average summer retention time within Fisk I I -5- I JASON M.CORTELL I ANDASSOCIATES INC. Pond can be doubled to nearly one and one-half weeks by the installation of a flow diversion curtain. The cost of such flow diversion materials was estimated at $21,700.00 in 1979. Each application by boat would cost I $7,447.00 for manpower and materials. With detailed water quality monitoring costs included and six applications of chemical, the total cost in 1979 was estimated at $74,000.00 per summer.