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HomeMy WebLinkAbout08/27/2019 - Final Stormwater Report & O&M Plan (Part 3) - 481 Sutton Street OPERATION AND MAINTENANCE PLAN PREPARED AS A SEPARATE DOCUMENT TO BE USED BY THE DPW AND SENIO CENTER FOLLOWING PERMIT APPROVALS 69 North Andover Senior Center Operation and Maintenance for Stormwater Management North Andover Senior Center Surry Drive North Andover, Massachusetts Prepared by: Civil Engineer, Landscape Architect & Site Planner DeVellis Zrein Inc. PO Box 307 Foxboro, MA 02035 www.develliszrein.com August 27, 2019 DeVellis Zrein,Inc. August 27,2019 70 Introduction DeVellis Zrein Inc. has prepared this report as a guide to establish maintenance protocol for the on-site drainage improvements serving the Proposed Senior Center. The goal of the Storm Water Operation and Maintenance Plan is not only to protect off-site wetlands and water resources abutting the site, but also to protect those resources in the region that may be affected by the activities at the site. The Town of North Andover has many municipal facilities to manage and has a process in place. This plan makes suggestions to the DPW and Senior Center to work collaboratively to maintain the site with respect to stormwater management. The proposed site drainage improvements include: • Proprietary Water Quality Inlets (Engineered inlets such as Stormceptors and a CDS unit) • Catch Basins (with sumps and hoods) • Rain Gardens • Pervious Patio Pavers • Drain pipe network • Detention and Infiltration System The proposed water quality treatment measures will result in improved removal of the total suspended solids (TSS) load in runoff from the site for the proposed parking improvements as well as throughout the existing parking areas. An effective drainage maintenance program will ensure that the removal of TSS from the stormwater runoff continues for the life of the facility. The Operation and Maintenance Plan will be implemented by the Owner of the property. Source Control The first tier of non-structural controls includes a comprehensive source control program of regular sweeping and maintenance of the stormwater management components. Pavement Sweeping Program While certain types of street sweepers are not effective for the removal of fine particulates and pollutants associated with them, most are quite effective for the removal of large quantities of sand, grit, and assorted inorganic and organic debris. Larger material carried in storm water poses an environmental threat not only by degrading aesthetics, but may also contribute pollutants as it degrades over time. In addition, larger materials may clog conveyance systems, reduce the efficiency and longevity of treatment systems and ultimately result in more maintenance downstream. The removal of contaminants directly from paved surfaces before contact with storm water is a valuable method for reducing pollutant loading in stormwater. DeVellis Zrein, Inc. August 27,2019 71 It is proposed that the parking and drive areas will be cleaned with a street sweeper on a quarterly basis with at least FOUR SWEEPINGS PER YEAR or more often as required if conditions require it. Water Quality Unit The new proprietary water quality units at the site will be equipped with specific catchment systems that will need to be cleaned per manufacturer's specifications. The manufacturer's recommendations are attached to this report and depending on the winter, salt and sand practices of the town, the frequency of maintenance will vary. The staff responsible for maintaining the site shall read the material within this report and adhere to the minimum standards and adjust as the conditions require. Rain Garden The rain garden should be cared for like any flower garden with several exceptions. The plant selection has been made by a landscape architect and represents a selection that is indigenous to New England, can survive in wet and dry conditions with little use of fertilizers or excessive watering. The inlet pipes or curb openings shall be kept clear of obstruction. Side slopes shall be kept planted and side erosion shall be avoided. Note that the drainage system's ability to mitigate peak runoff is not effected by the installation of the rain gardens and they are being proposed only as an amenity to the site. Pervious Patio Pavers While certain types of leaf blowers are not effective for the removal of fine particulates and pollutants associated with them, most are quite effective for the removal of sand, grit, and assorted inorganic and organic debris. Larger material carried in storm water poses an environmental threat not only by degrading aesthetics, but may also contribute pollutants as it degrades over time. In addition, larger materials may clog conveyance systems, reduce the efficiency and longevity of treatment systems and ultimately result in more maintenance downstream. The removal of contaminants directly from paver surfaces before contact with storm water is a valuable method for reducing pollutant loading in stormwater. It is proposed that the pervious patio paver patio be cleaned with a leaf blower on a semi-annual basis (spring and fall), with at least two blowings per year. Note that the drainage system's ability to mitigate peak runoff is not effected by the installation of the pervious pavers and they are being proposed only as an amenity to the site. DeVellis Zrein, Inc. August 27,2019 72 Detention and Infiltration System The actual removal of sediments and associated pollutants and trash occurs only when inlets are cleaned out; therefore, regular maintenance is required. The stormwater that enters into the infiltration system will be devoid of sediment due to the TSS removal within the components leading up to the system. In order for sediment to reach the system, it would have to pass through the raingardens, catch basins and/or water quality inlets before reaching the infiltration system. All of the treatment components referenced provide a higher level of sediment removal than required and it is very unlikely that sediment will accumulate in the system. If sediment is observed in the system it can be easily removed with a vacuum truck similar to a septic system pumper. The underground detention and infiltration basin has been designed with manholes and pipes for easy access and viewing. There are 4-foot diameter manholes at corners of the system (4 total) and 18-inch header pipes along the sides connecting to 18-inch diameter perforated infiltration pipes, accessed from each manholes that are provided for easy viewing and maintenance. Estimated Operations Budget A yearly estimated operations budget for consideration to carry out the Operations and Maintenance Plan requirements is as follows: • $0: Inspect the perimeter landscaping annually, in the spring, for erosion of side slopes, embankments, and accumulated sediment. Necessary sediment removal, earth repair and/or reseeding shall be performed immediately upon identification. • $3000: Clean all water quality structures to remove accumulated sand, sediment, and floatable products. Dispose and transport accumulated sediment off-site in accordance with applicable local, state and federal guidelines and regulations. This should be incorporated into the DPW routine maintenance protocol. • $500: Remove accumulated leaves and debris from catch basins and outlet openings. • $500: Routinely pick up and remove litter from the parking areas, islands and perimeter landscape area, in addition to pavement sweeping. • $500: Replant/replenish the rain gardens with specific plantings. Trim and prune as needed. DeVellis Zrein, Inc. August 27,2019 73 Stormwater Operation & Maintenance Overview Plan DeVellis Zrein, Inc. August 27,2019 74 / NORTH ANDOVER ,63 ADULT CENTER 62 ., NORTH ANDOVER,MA 6� PERVIOUS PATIO 2 STORY BUILDING O •�` a RAIlv GARDENS s,A& �•��� ® INLET �s . A -gOW p OULET DZ I o CA BASIN O T DeVellis Zrein Inc. �B►ast 68 RAMS GYP) ffy 165 my OPERATION& MAINTENANCE O T OVERVIEW 153 FOR SITE 163 162 VEGETATED — 0 G'° SWALE •------- — — — — — --- O&M Engineered Water Quality Unit Information DeVellis Zrein, Inc. August 27,2019 76 C%oNTECH® ENGINEERED SOLUTIONS Stormceptor° STC Owner's Manual 0010 r 0 +R x a r 3 Y ! � � a rr 77 Table of Contents TITLE..........................................................................SECTION Stormceptor Overview ................................................................. 1 Stormceptor Operation and Components ....................................2 Stormceptor Identification ...........................................................3 Stormceptor Inspection and Maintenance ...................................4 Recommended Stormceptor Inspection Procedure Recommended Stormceptor Maintenance Procedure Contact Information .................................................................... 5 For patent information, go to www.ContechES.com/ip. 78 2 StormceptorO Owner's Manual Your selection of a Stormceptor)means that you have chosen the PLEASE MAINTAIN YOUR STORMCEPTOR most recognized and efficient stormwater oil/sediment separator available for protecting the environment. Stormceptor is a pollution To ensure long-term environmental protection through continued control device often referred to as a "Hydrodynamic Separator performance as originally designed for your site, Stormceptor must (HDS)"or an "Oil Grit Separator(OGS)", engineered to remove and be maintained, as any stormwater treatment practice does.The need retain pollutants from stormwater runoff to protect our lakes, rivers for maintenance is determined through inspection of the Stormcep- and streams from the harmful effects of non-point source pollution. tor. Procedures for inspection are provided within this document. Maintenance of the Stormceptor is performed from the surface via vacuum truck. 1 - Stormceptor Overview If you require information about Stormceptor,or assistance in finding resources to facilitate inspections or maintenance of your Stormceptor is a patented stormwater quality structure most often Stormceptor please call Contech at 1-800-338-1122. utilized as a treatment component of the underground storm drain network for stormwater pollution prevention. Stormceptor 2 - Stormceptor Operation and is designed to remove sediment,total suspended solids(TSS), Components other pollutants attached to sediment, hydrocarbons and free oil from stormwater runoff. Collectively the Stormceptor provides spill Stormceptor is a flexibly designed underground stormwater quality protection and prevents non-point source pollution from entering treatment device that is unparalleled in its effectiveness for pollut- downstream waterways. ant capture and retention using patented flow separation technol- ogy. Stormceptor creates a non-turbulent treatment environment Key benefits of Stormceptor include: below the insert platform within the system.The insert diverts water • Removes sediment, suspended solids, debris, nutrients, heavy into the lower chamber, allowing free oils and debris to rise, and metals, and hydrocarbons (oil and grease)from runoff and sediment to settle under relatively low velocity conditions.These snowmelt. pollutants are trapped and stored below the insert and protected from large runoff events for later removal during the maintenance • Will not scour or re-suspend trapped pollutants. procedure. • Provides sediment and oil storage. • Provides spill control for accidents,commercial and industrial With thousands of units operating worldwide, Stormceptor delivers developments. reliable protection every day, in every storm.The patented Stormcep- • Easy to inspect and maintain (vacuum truck). for design prohibits the scour and release of captured pollutants, ensuring superior water quality treatment and protection during • "STORMCEPTOR" is clearly marked on the access cover(ex- even the most extreme storm events. Stormceptor's proven perfor- cluding inlet designs). mance is backed by the longest record of lab and field verification in • Relatively small footprint. the industry. • 3rd Party tested and independently verified. • Dedicated team of experts available to provide support. Model Types: • STC(Standard) • EOS(Extended Oil Storage) • OSR(Oil and Sand Removal) • MAX (Custom designed unit, specific to site) Configuration Types: • inlet unit(accommodates inlet flow entry, and multi-pipe entry) • In-Line(accommodates multi-pipe entry) • Submerged Unit(accommodates the site's tailwater condi- tions) • Series Unit(combines treatment in two systems) 79 Stormceptor Owner's Manual 3 Stormceptor Schematic and Component Functions Below are schematics of two common Stormceptor configurations with key components identified and their functions briefly described. • Manhole access cover—provides access to the subsurface components • Precast reinforced concrete structure—provides the vessel's watertight structural support • Fiberglass insert—separates vessel into upper and lower chambers • Weir—directs incoming stormwater and oil spills into the lower chamber • Orifice plate—prevents scour of accumulated pollutants • Inlet drop tee—conveys stormwater into the lower chamber • Fiberglass skirt—provides double-wall containment of hydrocarbons • Outlet riser pipe—conveys treated water to the upper chamber; primary vacuum line access port for sediment removal • Oil inspection port—primary access for measuring oil depth and oil removal • Safety grate—safety measure to cover riser pipe in the event of manned entry into vessel Figure 1. Figure 2. Inline Stormceptor Inlet Stormceptor Acres,;Cover Inlet Grate Oil Port pit Fort Orifice Plate �Urt Onti<,r,>Plate Safety Grate Weir ;; '�ll�ial Weir Ii,D 1 10"Skirt ,�e i Fiberglass Insert � Fdr<=.r7lassInsert Inlet Drop Tee • 1ES"5bd � * 24"0 Outlet Pipe Outlet Pipe Precr'rsl piero(orcxd 20///�„ Removable Inlet Conuete structure III�ry � DrnpTree T iG /,, 3 - Stormceptor Identification Stormceptor is available in both precast concrete and fiberglass vessels,with precast concrete often being the dominant material of construction. In the Stormceptor, a patented,engineered fiberglass insert separates the structure into an upper chamber and lower chamber.The lower chamber will remain full of water, as this is where the pollutants are sequestered for later removal. Multiple Stormceptor model(STC, OSR, EOS and MAX)configurations exist,each to be inspected and maintained in a similar fashion. Each unit is easily identifiable as a Stormceptor by the trade name"Stormceptor"embossed on each access cover at the surface.To determine the location of"inlet" Stormceptor units with horizontal catch basin inlet, look down into the grate as the Stormceptor insert will be visible.The name"Stormceptor" is not embossed on inlet models due to the variability of inlet grates used/approved across North America. Once the location of the Stormceptor is determined,the model number may be identified by comparing the measured depth from the fiberglass insert level at the outlet pipe's invert(water level)to the bottom of the tank using Table 1. In addition,starting in 1996 a metal serial number tag containing the model number has been affixed to the inside of the unit, on the fiberglass insert. If the unit does not have a serial number,or if there is any uncertainty regarding the size of the unit using depth measurements, please contact your local Contech Representative for assistance. 80 4 Stormceptor"Owner's Manual Sizes/Models Typical general dimensions and capacities of the standard precast STC, FOS and OSR Stormceptor models are provided in Tables 1 and 2. Typical rim to invert measurements are provided later in this document.The total depth for cleaning will be the sum of the depth from outlet pipe invert(generally the water level)to rim (grade)and the depth from outlet pipe invert to the precast bottom of the unit. Note that depths and capacities may vary slightly between regions. Table 1.Stormceptor Dimensions-Insert to Base of Structure Table 2.Storage Capacities STC Model Insert to Base(in.) STC Model Hydrocarbon Storage Sediment Capacity 450 60 Capacity(gal) (ft3) 900 55 450 86 46 1200 71 900 251 89 1800 105 1200 251 127 2400 94 1800 251 207 3600 134 2400 840 205 4800 128 3600 840 373 6000 150 4800 909 543 7200 134 6000 909 687 11000* 128 7200 1059 839 13000* 150 11000* 2797 1089 16000* 1 134 13000* 2797 1374 16000* 3055 1677 Notes: Notes: 1.Depth Below Pipe Inlet Invert to the Inside Top Base Slab can vary slightly 1.Hydrocarbon and Sediment capacities can be modified to accommodate by manufacturing facility,and can be modified to accommodate specific site specific site design requirements,contact your local representative for designs,pollutant loads or site conditions. Contact your local representative assistance. for assistance. *Consist of two chamber structures in series *Consist of two chamber structures in series. 4 — Stormceptor Inspection and Sediment removal is easier when removed on a regular basis Maintenance at or prior to the recommended maintenance sediment depths, as sediment build-up can compact making removal Regular inspection and maintenance is a proven, cost-effective way more difficult. to maximize water resource protection for all stormwater pollution The unit should be cleaned out immediately after an oil,fuel control practices, and is required to insure proper functioning of the or chemical spill. Stormceptor. Both inspection and maintenance of the Stormceptor What conditions can compromise Stormceptor is easily performed from the surface. Stormceptor's patented performance? technology has no moving parts, simplifying the.inspection and If construction sediment and debris is not removed prior to maintenance process. activating the Stormceptor unit, maintenance frequency may Please refer to the following information and guidelines before be reduced. conducting inspection and maintenance activities. If the system is not maintained regularly and fills with sedi- ment and debris beyond the capacity as indicated in Table 2, When is inspection needed? pollutant removal efficiency may be reduced. • Post-construction inspection is required prior to putting the If an oil spill(s)exceeds the oil capacity of the system, subse- Stormceptor into service. quent spills may not be captured. • Routine inspections are recommended during the first year of If debris clogs the inlet of the system, removal efficiency of operation to accurately assess the sediment accumulation. sediment and hydrocarbons may be reduced. • Inspection frequency in subsequent years is based on the If a downstream blockage occurs, a backwater condition may maintenance plan developed in the first year, occur for the Stormceptor and removal efficiency of sediment • Inspections should also be performed immediately after oil, and hydrocarbons may be reduced. fuel,or other chemical spills. What training is required? When is maintenance cleaning needed? The Stormceptor is to be inspected and maintained by professional • For optimum performance,the unit should be cleaned out vacuum cleaning service providers with experience in the once the sediment depth reaches the recommended main- maintenance of underground tanks,sewers and catch basins. tenance sediment depth,which is approximately 15%of For typical inspection and maintenance activities, no specific the unit's total storage capacity(see Table 3).The frequency supplemental training is required should be adjusted based on historical inspection results due to variable site pollutant loading. 81 Stormceptor Owner's Manual 5 Recommended Stormceptor Inspection Procedure: What equipment is typically required for • Stormceptor is to be inspected from grade through a stan- maintenance? dard surface manhole access cover. Vacuum truck equipped with water hose and jet nozzle • Sediment and oil depth inspections are performed with a Small pump and tubing for oil removal sediment probe and oil dipstick. Manhole access cover lifting tool • Oil depth is measured through the oil inspection port, either Oil dipstick/Sediment probe with ball valve(typically 3/4-inch a 4-inch or 6-inch diameter port. to 1-inch diameter) • Sediment depth can be measured through the oil inspection Flashlight port or the 24-inch diameter outlet riser pipe. Camera • Inspections also involve a visual inspection of the internal Data log/Inspection Report components of the system. • Safety cones • Hard hats, safety shoes, safety glasses, chemical-resistant gloves, and hearing protection for service providers • Gas analyzer, respiratory gear, hoist and safety harness for specially trained personnel if confined space entry is required Figure 3. Figure 4. a� ti /'iew,From` Finish Grade Orifice Pla Weir Safety Gra (Open Pos Oil Port 24"0 Outl • 82 6 Stormceptor'Owner's Manual Recommended Stormceptor Maintenance Procedure Ideally maintenance should be conducted during dry weather Maintenance of Stormceptor is performed using a vacuum truck. conditions when no flow is entering the unit. No entry into the unit is required for maintenance. DO NOT ENTER Stormceptor is to be maintained through a standard surface THE STORMCEPTOR CHAMBER unless you have the proper personal manhole access cover. safety equipment, have been trained and are qualified to enter Insert the oil dipstick into the oil inspection port. If oil is pres- a confined space,as identified by local Occupational Safety and ent, pump off the oil layer into separate containment using a Health Regulations(e.g. 29 CFR 1910.146).Without the proper small pump and tubing. equipment,training and permit,entry into confined spaces can Maintenance cleaning of accumulated sediment is performed result in serious bodily harm and potentially death. Consult local with a vacuum truck. and/or state regulations to determine the requirements for confined For 6-ft diameter models and larger,the vacuum hose is space entry. Be aware,and take precaution that the Stormceptor inserted into the lower chamber via the 24-inch outlet fiberglass insert may be slippery. In addition, be aware that some riser pipe(See Fig. 5). units do not have a safety grate to cover the outlet riser pipe that leads to the submerged, lower chamber. For 4-ft diameter model,the removable drop tee is lifted out, and the vacuum hose is inserted into the lower chamber via the 12-inch drop tee hole(See Fig. 6). Figure 5. Figure 6. M1 K r H >� € L u IN MR L 61 IN • Using the vacuum hose, decant the water from the lower chamber into a separate containment tank or to the sanitary sewer, if per- mitted by the local regulating authority. • Remove the sediment sludge from the bottom of the unit using the vacuum hose. For large Stormceptor units, a flexible hose is often connected to the primary vacuum line for ease of movement in the lower chamber. • Units that have not been maintained regularly, have surpassed the maximum recommended sediment capacity, or contain damaged components may require manned entry by trained personnel using safe and proper confined space entry procedures. What is required for proper disposal? The requirements for the disposal of material removed from Stormceptor units are similar to that of any other stormwater treatment Best Management Practices(BMP). Local guidelines should be consulted prior to disposal of the separator contents. In most areas the sediment, once dewatered,can be disposed of in a sanitary landfill. It is not anticipated that the sediment would be classified as hazardous waste.This could be site and pollutant dependent. In some cases,approval from the disposal facility operator/agency may be required. What about oil spills? Stormceptor is often implemented in areas where there is high potential for oil,fuel or other hydrocarbon or chemical spills. Stormceptor units should be cleaned immediately after a spill occurs by a licensed liquid waste hauler.You should also notify the appropriate regulatory agencies as required in the event of a spill. What if I see an oil rainbow or sheen at the Stormceptor outlet? With a steady influx of water with high concentrations of oil, a sheen may be noticeable at the Stormceptor outlet.This may occur because a hydrocarbon rainbow or sheen can be seen at very small oil concentrations(< 10 ppm). Stormceptor is effective at removing 95%of free oil, and the appearance of a sheen at the outlet with high influent oil concentrations does not mean unit is not working to this level of removal. In addition, if the influent oil is emulsified,the Stormceptor will not be able to remove it.The Stormceptor is designed for free oil removal and not emulsified or dissolved oil conditions. 83 Stormceptory Owner's Manual 7 What factors affect the costs involved with inspection/maintenance? The Vacuum Service Industry for stormwater drainage and sewer systems is a well-established sector of the service industry that cleans underground tanks,sewers and catch basins. Costs to clean Stormceptor units will vary. Inspection and maintenance costs are most often based on unit size,the number of units on a site,sediment/oil/hazardous material loads,transportation distances,tipping fees,disposal requirements and other local regulations. What factors predict maintenance frequency? Maintenance frequency will vary with the amount of pollution on your site(number of hydrocarbon spills, amount of sediment,site activ- ity and use,etc.). It is recommended that the frequency of maintenance be increased or reduced based on local conditions. If the sediment load is high from an unstable site or sediment loads transported from upstream catchments, maintenance may be required semi-annually. Conversely once a site has stabilized, maintenance may be required less frequently(for example:two to seven year,site and situation dependent). Maintenance should be performed immediately after an oil spill or once the sediment depth in Stormceptor reaches the value specified in Table 3 based on the unit size. Table 3.Recommended Sediment Depths Indicating Maintenance STC Model Maintenance Sediment Depth(in) 450 8 900 8 1200 10 1800 15 2400 12 3600 17 4800 15 6000 18 7200 15 11000* 17 13000* 20 16000* 17 Notes: 1. The values above are for typical standard units. *Per structure. Replacement parts Since there are no moving parts during operation in a Stormceptor, broken, damaged, or worn parts are not typically encountered.There- fore, inspection and maintenance activities are generally focused on pollutant removal. However, if replacements parts are necessary, they may be purchased by contacting your local Contech Representative or call 800-338-1122. The benefits of regular inspection and maintenance are many—from ensuring maximum operation efficiency,to keeping maintenance costs low,to the continued protection of natural waterways—and provide the key to Stormceptor's long and effective service life. 84 8 Stormceptorl Owner's Manual Stormceptor Inspection and Maintenance Loa Stormceptor Model No: Allowable Sediment Depth: Serial Number: Installation Date: Location Description of Unit: Other Comments: 5 - Contact Information Questions regarding the Stormceptor can be addressed by contacting your local Contech representative or by calling 800-338-1122. 85 Stormceptorl Owner's Manual 9 x e. z MM SUPPORT • Drawings and specifications are available at www.ContechES.com. • Site-specific design support is available from our engineers. ©2019 Contech Engineered Solutions LLC,a QUIKRETE Company Contech Engineered Solutions LLC provides site solutions for the civil engineering industry.Contech's portfolio includes bridges,drainage,sanitary sewer, stormwater,and earth stabilization products.For information,visit www.ContechES.com or call 800.338.1122 NOTHING IN THIS CATALOG SHOULD BE CONSTRUED AS A WARRANTY.APPLICATIONS SUGGESTED HEREIN ARE DESCRIBED ONLY TO HELP READERS MAKE THEIR OWN EVALUATIONS AND DECISIONS,AND ARE NEITHER GUARANTEES NOR WARRANTIES OF SUITABILITY FOR ANY APPLICATION.CONTECH MAKES NO WARRANTY WHATSOEVER,EXPRESS OR IMPLIED,RELATED TO THE APPLICATIONS,MATERIALS,COATINGS,OR PRODUCTS DISCUSSED HEREIN.ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND ALL IMPLIED WARRANTIES OF FITNESS FOR ANY PARTICULAR PURPOSE ARE DISCLAIMED BY CONTECH. SEE CONTECH'S CONDITIONS OF SALE(AVAILABLE AT WWW.CONTECHES.COM/COS)FOR MORE INFORMATION. CNTECH` ENGINEERED SOLUTIONS 800-925-5240 Stormceptor Owner's Manual 6/19 86 www.ContechES.com C w: NTECH® ENGINEERED SOLUTIONS CDS° Inspection and Maintenance Guide rf' r' Ir/i�/r�i%���/1/����r//Il%/,i✓„�. ��///il/� i:,"" „ i{,„ 91� /rid/if 1 �{ti�r�� i ��%i�l/i� // r/ I �r�/�/ � f ✓ /' � rr IINXGA,, NINE r'../i � r > r. rr rl riG /� "I l frl i K i II�III'IIl„\\\\ CIS TECHNOLOGIES 87 Maintenance Cleaning The CDS system should be inspected at regular intervals and Cleaning of a CDS systems should be done during dry weather maintained when necessary to ensure optimum performance. conditions when no flow is entering the system.The use of a The rate at which the system collects pollutants will depend more vacuum truck is generally the most effective and convenient heavily on site activities than the size of the unit. For example, method of removing pollutants from the system. Simply remove unstable soils or heavy winter sanding will cause the grit chamber the manhole covers and insert the vacuum hose into the sump. to fill more quickly but regular sweeping of paved surfaces will The system should be completely drained down and the sump slow accumulation. fully evacuated of sediment.The area outside the screen should also be cleaned out if pollutant build-up exists in this area. Inspection In installations where the risk of petroleum spills is small,liquid Inspection is the key to effective maintenance and is easily contaminants may not accumulate as quickly as sediment. performed. Pollutant transport and deposition may vary from However,the system should be cleaned out immediately in year to year and regular inspections will help ensure that the the event of an oil or gasoline spill should be cleaned out system is cleaned out at the appropriate time. At a minimum, immediately. Motor oil and other hydrocarbons that accumulate inspections should be performed twice per year(e.g.spring on a more routine basis should be removed when an appreciable and fall) however more frequent inspections may be necessary layer has been captured.To remove these pollutants, it may in climates where winter sanding operations may lead to rapid be preferable to use absorbent pads since they are usually less accumulations,or in equipment washdown areas. Installations expensive to dispose than the oil/water emulsion that may be should also be inspected more frequently where excessive created by vacuuming the oily layer.Trash and debris can be amounts of trash are expected. netted out to separate it from the other pollutants. The screen The visual inspection should ascertain that the system should be power washed to ensure it is free of trash and debris. components are in working order and that there are no Manhole covers should be securely seated following cleaning blockages or obstructions in the inlet and separation screen. activities to prevent leakage of runoff into the system from above The inspection should also quantify the accumulation of and also to ensure that proper safety precautions have been hydrocarbons,trash, and sediment in the system. Measuring followed. Confined space entry procedures need to be followed pollutant accumulation can be done with a calibrated dipstick, if physical access is required. Disposal of all material removed tape measure or other measuring instrument. If absorbent from the CDS system should be done in accordance with local material is used for enhanced removal of hydrocarbons,the level regulations. In many jurisdictions,disposal of the sediments may of discoloration of the sorbent material should also be identified be handled in the same manner as the disposal of sediments during inspection. It is useful and often required as part of an removed from catch basins or deep sump manholes. operating permit to keep a record of each inspection. A simple form for doing so is provided. Access to the CDS unit is typically achieved through two manhole access covers. One opening allows for inspection and cleanout of the separation chamber(cylinder and screen)and isolated sump. The other allows for inspection and cleanout of sediment captured and retained outside the screen. For deep units,a single manhole access point would allows both sump cleanout and access outside the screen. The CDS system should be cleaned when the level of sediment has reached 75%of capacity in the isolated sump or when an appreciable level of hydrocarbons and trash has accumulated. If absorbent material is used, it should be replaced when significant discoloration has occurred. Performance will not be r impacted until 100%of the sump capacity is exceeded however it is recommended that the system be cleaned prior to that a for easier removal of sediment. The level of sediment is easily ' °� x determined by measuring from finished grade down to the top of the sediment pile. To avoid underestimating the level of �, sediment in the chamber,the measuring device must be lowered to the top of the sediment pile carefully. Particles at the top of the pile typically offer less resistance to the end of the rod than consolidated particles toward the bottom of the pile. Once thisfr measurement is recorded, it should be compared to the as-built drawing for the unit to determine weather the height of the sediment pile off the bottom of the sump floor exceeds 75%oft �Ey the total height of isolated sump. �t���h 88 Distance,from'Water'Surface' Diameter Sediment Storage Capacity to Top of Sediment Pile CDS Model, ft m 'ft m Y3 m� . •.1. 111�� �1�L��© I • ���I�� I��• � . II I����■ ICI I • A�����,,,.,„#��,• `" '� ,` � �wgy'"�9ru 4,� � Wt� .n�{y"�t�,`�; y,r'~1����.�ql� i "y '� ,, dir', � ��$k"'ay, +, x a 1 n, • � �� °Cy✓ 1r>; i 5 r �1 rib�f + r 19 • � ! '��''�� a�i.�S�+i'�` [:;��'� '��� r� �'�'� ',�-;°,:,� �y�a'�,,'iro u °"'aJ` r rp ��� r� '4�.A-:. x (� '-_ (���.� „a`@`"y�., `�'pTi�)f��r�,r.,ti � 7r%%^"t ,•„i,, ° e'iIHA 4i r � a'' '4`"� r e ��,: 7 �a»a 4 w i!r/li r� r �., �r o y h Vl�ir arr• a F'A i. _. ._ r.... { �Gk.�k,.�llr�1/.�Ah�I�,rdtti,�ir'1GLA r W Support • Drawings and specifications are available at www.contechstormwater.com. • Site specific design support is available from our engineers. ,02017 Contech Engineered Solutions LLC,a QUIKRETE Company Contech Engineered Solutions LLC provides site solutions for the civil engineering industry.Contech's portfolio includes bridges,drainage,sanitary sewer, stormwater,earth stabilization and wastewater treament products.For information,visit www.ContechES.com or call 800.338.1122 NOTHING IN THIS CATALOG SHOULD BE CONSTRUED AS AN EXPRESSED WARRANTY OR AN IMPLIED WARRANTY OF MERCHANTABILITY OR FITNESS FOR ANY PARTICULAR PURPOSE.SEE THE CONTECH STANDARD CONDITION OF SALES(VIEWABLE AT WWW.CONTECHES.COM/COS)FOR MORE INFORMATION. The product(s)described may be protected by one or more of the following US patents: 5,322,629;5,624,576;5,707,527;5,759,415;5,788,848; 5,985,157;6,027,639;6,350,374;6,406,218;6,641,720;6,511,595;6,649,048;6,991,114;6,998,038;7,186,058;7,296,692;7,297,266;7,517,450 related foreign patents or other patents pending. CDS • • & Main tenance • • CDS Model: Location: Water Floatable Describe Maintenance Date depth to Layer Maintenance Comments Personnel sediment' Thickness' Performed 1. The water depth to sediment is determined by taking two measurements with a stadia rod:one measurement from the manhole opening to the top of the sediment pile and the other from the manhole opening to the water surface. If the difference between these measurements is less than the values listed in table 1 the system should be cleaned out. Note:to avoid underestimating the volume of sediment in the chamber, the measuring device must be carefully lowered to the top of the sediment pile. 2. For optimum performance,the system should be cleaned out when the ofloating hydrocarbon layer accumulates to an appreciable thickness.In the event of an oil spill,the system should be cleaned immediately. CDS Maintenance Guide-7/18(PDF) Maintenance Item and Maintenance Schedule DeVellis Zrein Inc August 27,2019 91 SITE OPERATION AND MAINTENANCE PLAN Project:NORTH ANDOVER SENIOR CENTER DATE:AUGUST 27,2019 EXTENT OF SERVICE DAILY(M-F) WEEKLY MONTHLY QUARTERLY TWICE/YR YEARLY AS NEEDED 1 SNOW REMOVAL PER O&M Plan X 2 EMPTY TRACH BARRELLS(internal trash with rollout barrels) X 3 GENERAL LANDSCAPING UPKEEP X 4 SPRING LANDSCAPE CLEANUP X 5 FALL CLEANUP X 6 PARKING LOT SWEEPING X 7 STORMCEPTOR/CATCH BASIN CLEANING X 8 RAINGARDEN LANDSCAPING X 9 ROOF GUTTER CLEANING X 10 INFILTRATION INSPECTION X 11 CLEANING BLOWN TRASH FROM SPERIMETER X Prepared by DeVellis Zrein, Inc. for use by the Town of North Andover's DPW and Senior Center Management Team N This document is a minimum guideline recommended to the Town to be used by the DPW and the Senior Center management's staff and team to develop a process for the maintenance and upkeep of the site and building. Once a process is decided,it is recommended that the facility prepare a signoff sheet with a final schedule and responsible parties for accountability