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HomeMy WebLinkAboutT16N R1W SEC 24 PARCEL A EKLUTNA ROCK QUARRY Rick Mystrom, Mayor Municipality of Anchorage Department of Health and Human Services 825 "L" Street P,O. Box 196650 Anchorage, Alaska 99519-6650 (907)343-4744 September 29, 1997 Mr. Joel A. Niemeyer US Department of Health and Human Services Division of Sanitation FaCilities Office of Environmental Health and Engineering Alaska Area Native Health Service 3925 Tudor Centre Drive Anchorage, AK 99508-5997 T16N R1W Section 24 Tract A Lot 9 - Permit #SW970118 Unapproved Installer Dear Mr. Niemeyer: This letter is concerning the above referenced permit #SW970118 for a wastewater disposal system installed on June 1997 by Mr. John Benedict of Benedict Constructions. As discussed on September 26, 1997 and per your request this letter is to inform you and for the record the current as-built received on July 18, 1997 will not be approved due to installation of wastewater disposal system by as unapproved installer. Tho Wastewater OrcVmance of Anchorage Municipal Code (AMC) 15.65.035A specifies the installer needs to be approved by this Department prior to engaging in the business of excavating (installing) wastewater disposal system. Inorder for the installer to be approved, he/she will need to attend a keminar offered by this Department and submit a permit fee of $320. As discussed on September 26, 1997, the consequences of this unapproved as-built can be denial of Health Authority Approvals if and when the housing unit in question exchanges ownership through the use of Lending Institutions. tfyou have any questions please do not hesitate to contact me at (907)343-4744. Sincerely, Civil Eng/neer On-site Services MUNICIPALITY OF ANCHORAGE DEPARTMENT OF HEALTH & HUMAN SERVICES On.Site Services Transmittal Sheet TO: LEGAL: The attached paperwork has been reviewed and is being returned for the following reason(s): __Discrepancy in legal description and/or owner name. __Discrepancy in number of bedrooms. __ Signature and/or stamp missing on i Show measured distances to sewers/wells, curtain drains and streams within 200 feet of proposed system. Replacement disposal site not shown and/or tested. Calculation error in design. -- Show locations of all soils, percolation or water table tests. __Proposed system too deep for soil test submitted. __Topographic information missing or inadequate. __Narrative missing or inadequate. __Additional soil/perc test needed. __ Sand filter requirements not satisfied. __Water monitoring results missing or inadequate because __ Incomplete; missing. __Well log required. __Water sample Unacceptable because. Please supply the necessary information and re-submit your request. Your cooperation is appreciated. Reviewer. Date LEA VE THIS FORM ATTACHED TO PAPERWORK /203-rev. 4/93 Municipality of Anchorage Page DEPARTMENT OF HEALTH AND HUMAN SERVICES ENVIRONMENTAL SERVICES DIVISION P.O. Box 196650 · Anchorage, Alaska 99519-6650 · Telephone: 343-4744 On-Site Wastewater Disposal System and/or Well Inspection Report Permit Number: d-~[4/':~7"~O //'~ RID Number: Name: b~ ~C~ Wastewater System: UNew ~Upgrade Address: {~,0, ~ l~O ~/~C~ q~ ABSORPTION FIELD Phone: ~ 0~0~ ~ No. of Bedrooms: ~ ~ ~ Deep Trench ~ Shallow Trench ~Bed ~ Mound ~ Other Total Depth fro~ original grade: LEGAL DESCRIPTION So,~a~,.~: ~. ~ ~,~/sq.,~. Township: [~ ~ Range: ~ I Section: ~ Fill added above original grade: Gravel length~/~ ~ Ft. F~. Number of lines: ~Distance bergen lines: WELL~ New · ~Upgrade Gra~e, width: ~ Ft. ~ ~t. Ciassificatio~Private, A.B C): ~ ~ Ft. Cased TO: Ft. Total absorption area:~ ~ Pipe material: ~ Pump Set at:, Casing Height Above Ground: SEPARATION DISTANCES ~s~pti~ ~a Holding ~ S.T.E.P. TO Septic Absorption Lift Holding 3ublic/Privat~Manufacturer: Capacityin gaUons: su~w~t~ ~ ~ ~ ~ ~ LIFT STATION Lot Line 4~1 ~ ~' d~ d ~ d ~ Size in ~s: I Manufa~: Foundation ¢~' ~' ~ d~ ~ "Pump on"~,: I "Pump offset: I High w~arm at: Cu~ain brai, ,~ ~ ~ d> ~> Pump Mske &~ ] Electrical Inspectio~,ormed by: BENCH MARK Remarks: W~ ~ ~ ~ ~'~ Location and Description: ~ ~ ~ ~~ IAssumed ElevatiOn: ,spoct o,s po,o o · O,tos: :st Department of Health and Human ~e~ices approval ~t~, c~ .**~ ~.~. ...... ~ ~,~ Reviewed and approved by: Date:. 72-013 [Rev. 9/91) MOA 25 TRACT B 3,132,711 SF 71.g2 AC N90'OO'OO"E 435.00' 217,800 SF 5.0 AC AS BUILT DI~AINFIELD SEE DETAIL SHEETS 1&2 125' 615-S SECOR J ~ TR A NBA PROP ¥ SCALE 1"=100' TRACT A NBA PROPERTY TOWNSHIP 16N RANGE lW SEWARD MERIDIAN MOA PERMIT # SW§70118 SECTION 25 REVISIONS u.s. D~^~m~.~,u~L,c .E*Lm S~R'~CEOr .~*m ~ ,,U~, Sm~C~S EKLU TNA. ALASKA ]~,,o~[c~ ,o. °[~~? ~1 ~ LEO STEPHAN 5925 ~DOR CENTRE ORI~ I/DRA~ BY: HRD m DATE: 2 4 PAGE 1 OF MUNICIPALITY OF ANCHORAGE DEPARTMENT OF HEALTH AND HUM/AN SERVICES P.O. BOX 196650, 825 "L" STREET, ROOM 502 ANCHORAGE, ALASKA 99519-6650 ON-SITE WASTEWATER DISPOSAL SYSTEM (UPGRADE) PERMIT PERMIT NUMBER:SW970118 DESIGN ENGINEER: OWNER NANE:LEO STEPTHAN OWNER ADDRESS:P.O. BOX 140533 ANCHORAGE, AK. 99514 DATE ISSUED: 5/05/97 EXPIRATION DATE: 5/05/98 PARCEL ID:05201110 LEGAL DESCRIPTION: ~ T16N R1W SEC 24 PARCEL A LOT SIZE:J~185268 (SQ. FT.) NUMBER OF BEDROOMS: 1 THIS PERMIT: 1 THIS PERMIT IS FOR THE CONSTRUCTION OF: DISPOSAL FIELD /SEPTIC TANK SYSTEM ALL CONSTRUCTION MUST BE IN ACCORDANCE WITH: 1. THE ATTACHED APPROVED DESIGN. 2. ALL REQUIREMENTS SPECIFIED IN ANCHORAGE MUNICIPAL CODE CHAPTERS 15.55 AND 15.65 AND THE STATE OF ALASKA WASTEWATER DISPOSAL REGULATIONS (18AAC72) AND DRINKING WATER REGULATIONS (18AAC80). 3. THE ENGINEER MUST NOTIFY DHHS AT LEAST 2 HOURS PRIOR TO EACH INSPECTION. PROVIDE NOTIFICATION BY CALLING 343-4744 ( 24 HOURS ) (NOT REQUIRED FOR WELL ONLY PERMIT) 4. FROM OCTOBER 15 TO APRIL 15 A SUBSURFACE SOIL ABSORPTION SYSTEM UNDER CONSTRUCTION DURING FREEZING WEATHER MUST BE EITHER: Ao OPENED AND CLOSED ON THE SAME DAY B. COVERED, SEALED AND HEATED TO PREVENT FREEZING 5.~jTHE~ FOLLOWING SPEcI~ PROVISIONS. SPECIAL PROVISIONS: 1.) VERIFY INTEGRITY (DF EXiSTiNG SEPTIC TANK; i. 2.) PROPERLY DECOMMISSION EXISTING DRAINFIELD. RECEIVED BY: ~ ~' %/ v ~/ ~ ~ Municipality of Anchorage DEPARTMENT OF HEALTH & HUMAN SERVICES 825 "L' Street, Anchorage, Alaska 99502-0650 SOILS LOG -- PERCOLATION TEST 2 3 4 5 6 7 8 9 10 SLOPE SITE PLAN ENCOUNTERED? S 11 L IF YES, AT WHAT DEPT"? VA' ? 12 E Deplh lo Water After 13 - Monitoring? ~ate: 14- 15- 16 17- 18- 19- 20- Gross Net Depth to Net Reading Date Time Time Water Drop PERCOLATION RATE J'J~'"~ (rmnutes/inch) PERC HOLE DIAMETER TEST RUN B~TWEEN [~ .FT AND 11 "EBFOB~"DBY ~5~ ~'~ ~'~7 ' CERTIFY THAT THIS TEST WAS PERFORMED IN ACCORDANCE WITH ALL STATE AND MUNICIPAL GUIDELINES IN EFFECT ON THIS DATE. DATE: 72-008 {Rev. 4/85) Municipality of Anchorage DEPARTMENT OF HEALTH & HUMAN SERVICES 825 "L" Street, Anchorage, Alaska 99502-0650 LEGAL DESCRIPTION: DEPTH 7 8 9 10 11 12 13 14 15- 16- 17- 18- 19- 20- SLOPE WASGROUNDWATER ~, 0 ENCOUNTERED? S L IF YES, AT WHAT ~ DEPTH? pO E Depth to Woter Ailnr Monitoring? . . Date: SITE PLAN Gross Net Depth to Net Reading Date Time Time Water Drop PERCOLATION RATE __ tmmutes/inch) PERC HOLE DIAMETER __ , .... ,'~" ' o ~ ' CERTIFY THA~ '~RIS TEST WAS PERFORMED IN ACCORDANCE WITH ALL STATE AND MUNICIPAL GUIDELINES IN EFFECT ON THIS DATE. DATE: 72-008 (Rev, 4/8~) DEPARTMENT OF HEALTH & HUMAN SERVICES Pttblic Health Service MEMORANDUM DATE: FROM: April 13, 1997 District Construction Engineer Alaska Area Native Health Service Alaska Area Native Health Service Office of Environmental Health and Engineering 3925 Tudor Centre Dr. Anchorage, Alaska 99508-5997 MAY 0,5 1997 Referto: ^-OEH E SUBJECT: Narrative Description - Municipality of Anchorage (MOA) On Site Waste Water Permit Application, Leo Stephan Residence, Eklutna Alaska. TO: Record This memo is written to outline the installation of an on-site waster water disposal system at the Leo Stephan residence in Eklutna, Alaska. Synopsis The Indian Health Service (IHS), in cooperation with the Cook Inlet Tribal Council has a project to serve native homeowners with on-site water and sewer systems in the Eklutna area. The IHS Office of Environmental health and Engineering will design the systems on behalf of the homeowners. Site Description This site is owned by Mr. Stephan and'totals 5 acres. The area is in a remote location of the Eklutna area. There are no adjacent lots, or structures within approximately 1/2 of a mile. The area is unsubdivided and the lots boarder the Alaska Railroad Railway Easement to the south. The nearest structure or developed lot is approximately 1/2 of a mile towards the south of the lots in consideration for on-site services. Soils investigation showed no signs of water table. Services The site is heavily treed with a flat slope in all directions. Soils investigation shewed well drained sandy gravels with an average percolation rate of 2.9 minutes per inch of water drop. This rate corresponds to an application rate of 0.8 gallons per day per square foot of drainfield~ S0i.ls testholes on the site showed highly consistent soil strata, with any deviation frdm' thb evid?hced strata unlikely. Exi~ir4~,.i services are on ~¢ite cor,~sist of a l~t-septic tank with two short perforated drainfield pipes, ' a.n,:,' a drilled and cased water well. The water well is adequate, no work will be performed on the well. The water service line will be replaced with insulated arctic utilidor to protect it from freezing under the driveway. The septic drainfield is inadequate and will be abandoned according to all local, state, and federal regulations. Proposed services include a new HDPE water service line, and infiltrator wastewater drainfield system. The sewer service line will be encased in insulated arctic utilidor to protect it from frost. All separation distances as stated by the Alaska Department of Environmental Conservation shall be exceeded for all components of the water and waste water systems. Probable Impacts to adiacent Properties Since this site is relatively remote, it is unlikely there will be any impacts to surrounding water or wastewater systems. There are no known water well or sewer systems within 1/2 of a mile from the proposed systems. Additionally, there remains adequate area for a replacement drainfield system at various locations on the property. er, PE District Construction Engineer * . U.S, GOVERNMENT :: -- ' : : SELLER--Pleasereadinstruc~ns on Copy2 PAYMENT r'IREc[ivEo ,~ ............................ [] PAYMENT REQUESTED NO FURTHER INVOICE NEED BE SUBMITTED ' IN~?~UOT~ON$ ?0 SEI. L£~ After satLsfactory identification of the Government representative presenting this purchase order, verify the itemization, including quantity, (mit price, amount, ffyou would rather submit your own invmce, DO NOT SIGN COPY 1, but attach 05/12/97 15:59 ~'907 271 4734 PHS AANHS OEH&E ~001/002 Fax Transmission Alaska Area Native Health Service Office of Environmental Health & Engineering 3925 TUI~OR CENTRE AN(:;HORAGE, AK cO950S '~Pages:, including cover sheet From: Hugh R Denny MESSAGE: 05/12/97 15:38 9907 271 4734 PH,S.AANHS 0EH&E · -.~. ~/%' ,, ~ · ~ / .~ ~, ~'~', . ~.~- ? [~003/003 LOT d 05/12/97 15:37 8907 271 4734 PHS AANHS OEH&E ~001/003 Fax Transmission Alaska Area Native Health Service Office of Environmental Health & Engineering 3 ~Pages:, including cover sheet I Subject: Hugh R De,my, MESSAGE: 05/12/97 - 41 15:38 9907 271 4734 PHS AANItS OEH&E 'PA(E 026E AS 34.15.040 TBS GRANTOr, NA?ZONAL ~NK O~ A~SgA, ~ nm~/onaZ ~ankLng association, Esr ~nd In consideration n~ ~gN DOLORS ($10.00) and other good and valu~le consideration Ln hand paLd, the receLp~ sE which ~8 hereb~ aoknovledged~ convey and to LEO STSP~N and ALBBRTA ~. STiPeNd. Husband ass whose maclang address ~e P.O, Box 8S33, ~chorage, ~laBka, 99508, ax~ eagerest vhXch ~t has, ii any, i~ the ~o~lovi~g descrLbed real estate located Ln the ~chofage Tract A, N.B.A. Pto~hy Eklutna~ *acco~ding ~o Plat No. 85-32, ~lled ~n the ~eborage Recording Dintrla~, ThLrd ~udicial DiStrict, State sE ~aoka. coven~ts, conditions ~d restr~c2~ons o~ record~ ~f DA~thi8 _2~_CJZ day o~ June, 198S. 062450 a national banking ' ANCHOflACE D(S[RICT A oucst ,, ..................... Bye ......... STATE OF ALASKA ) ) sa. TSZ~D JUDICZAL DZSTRZCT ) TBZS ZS TO C~RTIFY bhat on the ~___._ day o ~ June; 1985, before me a Notary P~llc ~n and ~or ~he ~te of mo bo be the _~_~ ........ of ~TZO~'~ OF AL~, a national banking annoata~ion, who aoknowledged to ~ :hat he execu2ed the ~o~e~oing docu~n2 on behalf sE na~d ~,o ~Xatlon its ~ard o~ Directors. last above ~r~tten. [~ 002/003 31V0 0 ~ I I' I I' I I I I ] I'l I I '1 I 0~0 ~ 0 (D 0°~ NYHd31S 039 V>lSVq¥ VNInq>I~ <'~ ©__ (sa43ul) do jO c~ GLENN HWY o o E m <~ < 0 O5 ~_ (5) D ~doo ~ W~ Z ~Dm The Infiltrator® Leach Field System SuppOrt Documentation 2/94 TABLE OF CONTENTS Introduction Documentation and Testing A. Stmc~ral Operational 1. Concrete Chamber Systems - Use and Acceptance a. Connecticut Department of Health Services b. USEPA Design Manual c. Accepted by Other Experts - University of Wisconsin and University of West Virginia 2. Gravel Masking a. USEPA Design Manual b. Soil Clogging - I. Bouma & Magdoff, 1974 2. Daniel & Bouma, 1974 c. Soil Clogging - Siegrist, 1987 C. Empirical 1. System a. b. d. e. Testing Australian Leaching Chamber Test Results Gravel-less Pipe, Anderson Machmeier, ASAE 1984 Maine Chamber Study, Hoxie and Frick, ASAE 1984 Maine Chamber Study - Nov. 1987 Maine Chamber Study USEPA International Symposium f. University of Wisconsin Study 2. System Performance a. State of'Georgia b. State of Maine III. Misconceptions IV. Sizing of Chamber Systems V. Summary and Conclusions VI. Bibliography The INFILTRATOR® unit is a leaching chamber molded from high density polyethylene. Standard units measure 6 I/4' x 3' x 1' high with 6" beneath the invert, and have a 6" sidewall. The INFILTRATOR® is engineered to eliminate the problems inherent with gravel trenches, and is the culmination of over two years of engineering, design and testing with input from environmental and structural engineers, state regulators and contractors. While the INFILTRATOR® chamber is a relatively new product, the method of sewage treatment and disposal has been thoroughly tested and has demonstrated operational competence with all types of effluent streams, flow rates, and in various kinds of soils, for many years. On site sewage disposal systems, designed using INFILTRATOR® chambers, use a conventional septic tank or pre-treatment system for primary or physical treatment of the waste. The leacking system is the critical component of any subsurface sewage disposal system, and the source of most system failures. Any leaching system, including INFILTRATOR® leaching chambers, must be designed and installed in accordance with t~vo basic principles: 1.The system must be designed with sufficient soil interface area for the effluent to move through a mature biological clogging layer into the soil. The crust layer is generally less permeabl.e than. the surrounding soil. Therefore, the crust layer determines the system size with respect to flow. 2.The system must be located in a hydrogeologic setiing that allows the effluent to pass through sufficient soil to be purified to the desired level. You can't put a system in a swamp. The siting requirements for all state building codes prescribes the proper hydrogeological setting. Various structures have been used over the years to achieve the interface area and storage capacity for the leach field. The most common is gravel, or crushed stone, filled trenches, with a perforated distribution pipe. The INFILTRATOR® is what is commonly called a chamber system. Concrete leaching chambers have been used extensively and successfully in the northeastern states for 20 years, and are generally regarded by engineers and regulators as being superior to gravel trenches. The INFILTRATOR® chamber uses no new technology, but operates on the same technology used by concrete leaching chambers. Only the material is different. INFILTRATOR® chambers will not change the hydraulics of the earth and, therefore will not make a bad site good. A proper hydrogeological setting, as defined by the state code, is still required. The following section presents data that shows that chamber technology has been used successfully for many years and is accepted, documented, and tested; and that additional testing is not necessary. It will al~o show, that chamber technology is superior to gravel filled systems. II. DOCUMENTATION AND TESTING The only concerns in changing the material from concrete to high density polyethylene is whether the chamber is strong enough to support the loads, and will the strength diminish with exposure to the effluent stream. INFILTRATOR* chambers are designed to comply to an H-10 AASHTO rating of 16,000 lbs/axle. Tests were conducted by Jack Stephens, a registered professional engineer and university professor of Civil Engineering. INFILTRATOR® chambers were tested to over 18,000 lbs/axle with 7" of cover and are guaranteed to support 16,000 lbs/axle vehicle loading with 12" of cover. Extra high strength units are available if needed. They have been successfully tested to over the H-20 loading of 32,000 lbs/axle with 18" of cover. High density polyethylene is a highly chemically resistant polymer that has been used for many years in septic tanks, pipe, and distribution boxes and is unaffected by the' components of the effluent stream or ground chemicals, and is stabilized to resist ultraviolet light. B. OPERATIONAL 1. Concrete chamber systems are used extensively, even at double the cost of gravel trenches, in the northeastern states. Engineers generally prefer them, because they are regarded as being superior to gravel trench systems. a. A letter from Frank S chaub, chief of the on-site sewage disposal section for the Connecticut of Health Services, explains that chambers have been accepted by the Connecticut code since 1970 and have been used with little problem, and have advantages, particularly for commercial systems. b. The USEPA Design Manual explains the use of concrete chambers in the design Section 7.2.8.1 g (p.296). The manual refers to concrete chambers as other distribution networks and also illustrates their use in Figure 7-33 (p.298). The USEPA shows this as accepted technology and states: "LEACHING CHAMBERS: IN PIMCE OF PERFORATED PIPE AND GRAVEL FOR DISTRIBUTION AND STORAGE OF THE WASTEWATER, THIS METHOD EMPLOYS OPEN BOTI'OM CHAMBERS... A LARGE NUMBER OF THESE SYSTEMS HA VE BEEN INSTALLED IN THE NORTHEASTERN UNITED STATES (see figure 7-33) ". c. Other experts in the field also have recoil?ed the acceptance and u.se of chamber Systems. Otis, Converse, Carlisle, and Witty, in a paper entitled "Effluent Distribution", ASAE 1977, on page 76, discuss Ameration chambers. "ANOTHER SI~STEM THAT DOES NOT USE GRA VEL V~ITHIN THE DRAINFIELD IS THE AMERATION SYSTEM THIS SYSTEM CONSISTS OF · CONCRETE CHAM~ERS WITH OPEN BOTTOMS THAT INTERLOCK TO FORM AN UNDERGROUND CAVERN 45cm.(18 inches) HIGH OVER THE EXPOSED INFILTRATIVE SURFACE. NO PIPE OR STONE IS USED. THE SEPTIC TANK EFFLUENT IS DISCHARGED INTO THE CAVERN THROUGH A CENTRAL V~EIR, TROUGH, OR SPLASHPLATE AND ALLOV~ED TO FLOltz OVER THE SURFACE IN ANY DIRECTION." The Ameration Chamber is discussed as an acceptable system with certain advantages. The University of West Virginia wrote a letter concerning the acceptance and use of concrete chambers. All of this goes to show the general recognition of chamber systems as accepted and proven technology. 2. Leaching chambers have many technical advantages compared to gravel filled trenches, including: greater storage capacity, ease of installation and inspection, and quality control. However, the most important advantage is the elimination of gravel or stone from the system and the negative attributes asseciated with it. Gravel emplacement compacts the infiltrative surface, and dust, or fines attached to the gravel rinse to the bottom of the system, both of which can significantly reduce long term rates. The most serious problem is the physical blocking or shadowing of the infiltrative surface. The literature refers to this phenomenon as gravel masking, or shadowing. a. The USEPA Design Manual addresses soil masking on page 226: "THE SUGGESTED GRAVEL OR ROCK SIZE IS 3/4" TO 2 1/2" (1.8 TO 6. 4 CM) IN DIAMETER. SMALLER SIZES ARE PREFERRED BECA USE MASKING OF THE INFILTRATIVE SURFACE BY THE ROCK IS REDUCED." b. The soil masking phenomenon was researched and explained in two papers by J. Bouma, formally with the University of Wisconsin. Bouma is considered by many to be - the father of wastewater disposal research and his work on application rates remains the standard for most state codes and the U.S. EPA Design Manual. 1. In a paper by J. Bouma and F. R. Magdoff, entitled "The Development of Soil Clogging in Sands Leached with Septic Tank Effluent" published in the 1974 ASAE Proceedings studied the resistance of the crust layer (Re). On page 41 Bouma states, "THE Rc OF ABOUT 500-600 HRS AT EQUILIBRIUM IS AN OVERESTIMATE OF THE RESISTANCE OF CRUSTAL MATERZ4L ITSELF.. THE GRAVEL LAYER HAD A SIGNIFICAIV'£ SURFACE AREA CONTACT WITH THE SAND AT THE GRA VEL-FILL INTERFACE, WHICH WAS VISUALLY ESTIMATED AT 60%. THE CLOGGED LAYER .DOES NOT FORM UNDERNEATH THE STONES AT THE INTERFACE. THE RESISTANCE OF THE CRUSTAL MATERIAL ITSELF IS, THEREFORE, ABOUT 40% OF THE CALCULATED Rc " Bouma clearly states that the stone masks about 60% of the surface area, or that 40% of the area is available for infiltration. 2. In a paper by T.C. Daniel and J. Bouma Titled "Column Studies of Soil Cloggil~g in a Slowly Permeable Soil as a Function of Effluent Quali~" 1974. Journal of Environmental Quality 3:4, The effect of soil masking is explained on page 325: "THE FIELD SYSTEM WOULD THUS BARELY BE ABLE TO ABSORB THE EFFLUENT PR OD UCED A T AN 1NFIL TRA TION RATE OF 1CM/DA Y, THE MORE SO SINCE THE FIELD SYSTEM HAS A SEEPAGE BED FILLED WITH GRAVEL, WHICH REDUCES THE EFFECTIVE INFILTRATIVE SURFACES BY AT LEAST 40%. " c. The soil masking phenomenon is also explained in a paper by R.L Siegr/st, "~oil Clogging During Subsurface Waslewater Infiltration as Affected by Composition and Loading Rate", t987. Journal of Environmental Quality, 16: 181-187. "A FEATURE OBSERVED IN THE CLOGGED SOIL CELLS, BOTH 1N THE FIELD AND IN THIN SECTION, WAS THE DISTINCT LACK OF EITHER ZONE OR ORGANIC MATTER ACCUMULATION (WITHIN OR ATOP THE SOIL MATRIX) IN LOCATIONS WHERE THE CELL AGGREGATE WAS IN DIRECT CONTACT WITH THE SOIL INFILTRATIVE SURFACE. THE INFILTRATIVE SURFACE AREA ACTUALLY AVAILABLE FOR WASTEWATER 1NFIL TRA TION MA Y HA VE BEEN S UBSTANTIALL Y RED UCED B Y THIS GRAVEL MASKING PHENOMEN03~ " You will note that Siegrist explains the makeup of the clogging layer for mature systems (with ponding). It was also observed that there was no accumulation of organic matter on top or within the soil directly bengath the stones, l-Ie concludes that the infiltrative surface actually available may have been substantially reduced. Basically, once the bio-mat forms, the effluent cmmot go through the stones but must pass through the bio-mat formed in the spaces between the stones. The problem becomes more serious as solid matter is washed into the trench from the septic tank, and deposited in the core spaces between the stones, further blocking the effluent's path to the soil. As referenced above, many scholars in the field believe that this effect results in 40% to 60% of the infiltrative surface being blocked, limiting the long term acceptance rate. Gravel systems have been empirically sized to account tbr this masking phenomenon. 1. System Testing Several independent studies have been conducted that illustrate the effect of the masking phenomenon on the long term acceptance rate of gravel systems. A brief discussion of each of these studies follows: a. A study conducted in Australia by Caldwell Cormell Engineers, for the Water Authority of Western Australia, makes a direct comparison of the infiltrative rate of an open bottomed chamber system with a gravel trench. Western Australia has always used chamber systems, originally using leach drain bricks on the trench sides with a concrete slab on the top. This construction has been replaced on most of the continent with plastic chambers introduced about 30 years ago. The test was set up to evaluate the American method of using a gravel or stone filled French drain as a leach field. Crushed, washed stone in Australia is called "blue metal". The purpose was to see if a stone-filled system would be superior. The tests were conducted under controlled conditions using large steel boxes, segmented to be able to separately measure sidewall and bottom infiltration. The soil used was a Bassendean sand as found in the region. The soil'in each steel box was tested to make sure they were identical before proceeding with the test. Three types of systems were tested: 1) the conventional chamber system with no stone 2) a chamber system with the brick side wall lined with 100 mm of stone, and 3) a stone-filled trench (French drain). The test results are presented in figures 7 - 11 through 7-14 of this study. Please note that the axis for infiltration rate is on a log scale and can not be scaled directly. Infiltrator Systems enlarged the graphs by a factor of 4 and used a log scale to interpolate between points. The data shows a decline in the infiltration rate as the biomat forms with the long term acceptance rate leveling off in approximately 172 days. The author of the paper concludes: (p. 131) "THE FRENCH DRAIN, OR BLUE METAL-FILLED TRENCH MODEL, SHOWED THE LOWEST TOTAL INFILTRATION RATE (SEE FIG. 7 - 14). THIS IS PRIMARILY BECAUSE OF THE VERY LOW EQUILIBRIUM RATE (15 MM/D) WHICH WAS OBTAINED THROUGH THE BOTTOM AREA OF THIS MODEL (SEE FIG. 7-]1). ALTHOUGH THE REASON FOR THIS IS UNKNOWN, IT MAY BE DUE TO PHYSICAL BLOCKING OF PART OF THE TRENCH BOTTOM OF THE BLUE METAL OR BY EXCESSIVE ATTACHED GROWTH ON THE BLUE METAL WHICH RESULTS IN CLOGGING OF THE VOID SPACES." Figure 7 - 13 shows the equilibrium rate for the open bottomed chamber systems to be about 34 mm/day compared to 15 mm/day for gravel trenches. Thus the equilibrium infiltration rate (LTAR) for the bottom area of the chamber system without stone is 2 I/4 times higher than for gravel or stone trenches (34 mm/day/l 5 mm/day = 2.26). To confirm the results of the experimental systems, the researchers also studied in ground, pilot plant systems in four different soils and locations for a period of four years. They compared the standard chamber system with gravel trenches (French drains), chambers with the sides backed up with gravel and soak wells (dry wells). The hydraulic loading for the french drain systems was about 15% lower than for the control systems (standard chambers), but failure still occurred. The author states: (P 135-136) "~-'I~DRA ULIC LOADINGS FOR THE BLUE-METAL FILLED FRENCH DRAINS WERE HIGHER THAN FOR OTHER TEST SYSTEMS, BUT LESS THAN THOSE FOR THE CONTROL SYSTEMS (TABLE 7-3). PONDED DEPTHS AT CANNING VALE, BEENYUP AND POINT PERON EXCEEDED FAILURE LEVELS AND PONDED WASTEWATER WAS OBSERVED ON THE GROUND SURFACE OVER AND ADJACEMENT TO THESE SYSTEMS ON A NUMBER OF OCCASIONS. AS JUDGED BY PONDED DEPTHS, THE PERFOR~MNCE OF THE FRENCH DRAIN TEST SYSTEMS WAS NOT SAT.[SFACTORK " "AS JUDGED BY RESTING INFILTRATION RATES, THE PERFORMANCE WAS POORER THAN THAT OF THE OTHER TEST AND CONTROL SYSTEMS." trench, 138: Because the gravel trenches were in failure, with water runn/ng out the top of the it was not possible to measure actual infiltration rates, as explained on pages 137- "AS INFILTRATION RATES AT PILOT PLANT UNITS WERE CALCULATED FROM PONDED DEPTH MEASUREMENTS, THE EXTENT TO WHICH RATES WERE AFFECTED BY WASTEWATER FLOODING ON THE SURFACE OF THE FRENCH DRAINS IS UNF~OWN. IN ANY EVENT, THE FLOODING OF PILOT FRENCH DRAINS DEMONSTRATES THE UNSUITABILFIT, AT THE HYDRA ULIC LOADINGS TESTED, OF THIS TYPE OF SOIL ABSORPTION SYSTEM FOR THE PERTH AREA." Please note that the standard chamber systems (control systems) handled higher loading rates without failure. This is a very well documented study clearly showing that the long term acceptance rate for the bottom area of open bottom chambers is 2.25 times that of gravel systems. b. Jim Anderson and Roger Machmeier, from the University of Minnesota, observed the same masking phenomenon in their study of large diameter, (10") gravel-less pipe. The results were published in the proceedings of the 1984 ASAE Symposium on Individual and Small Commnnity Sewage Systems. They observed that the outer corrugations were in firm contact with the soil, and provided no infiltrative surface. Only about 40% of the total surface area of the pipe was considered to be an effective infiltrative surface. The trenches were serially loaded using a drop box with a positive head, so that effluent was forced around the 3' perimeter of the pipe. Anderson and Macluneier found that the infiltration rate, per square foot of wetted area was about the same as for 3' wide gravel trench bottom area. This would imply that the masking effects of both graveMess pipe and gravel trenches are about the same - 60% masked. This agrees very closely with the masking effect shown in the Australian study and observed by Bouma. c. The effects of gravel masking are also shown in an on going study conducted by Donald Hoxie and Albert Frick fxom the state of Maine that evaluates the performance of chamber systems compared to gravel. Results were presented in a paper at the 1984 ASAE Symposium on Individual and Small Community Sewage Systems, entitled "Subsurface Wastewater Disposal Systems Designed in Maine by the Site Evaluation Method: Life Expectancy, System Design and Land Use Trends". This is a significant piece of research data clearly showing that chamber systems have not only demonstrated operational competence but are actually superior to gravel trenches. The state of Maine, recognizing the improved performance of chamber systems, (designed as beds) are 1/2 the size of gravel bed systems. Hoxie and Frick conclude: "THE RATIO OF BEDS TO CHAMBERS FAILURE RATE IS 10:1 AND THE RATIO OF BEDS TO CHAMBERS INSTALLED IS 8:1. THIS STATES THAT CHAMBERS DO NOT HA VE A HIGHER INCIDENCE OF FAILURE THAN BED SYSTEMS, ALTHOUGH 50% SMALLER THAN BED SYSTEMS FOR A GIVEN SOIL TYPE." d. The Maine chamber study is still being continued. Mr. Hoxie updated the results at our request in a letter to Tex LaRosa at the Vermont Agency of Environmental Engineering dated Nov. 29, 1987. The updated failure data shows even more positive results for the chamber systems. Mr. Hoxie states, "A PRELIMINARY REVIEW OF NEW DATA FROM 10, 025 PERA4ITS ISSUED IN 1986 SHOWED THAT FOR EVERY 6 NEW BED SYSTEMS BEING INSTALLED, 1 NEW CHAMBER SYSTEM WAS BEING INSTALLED (6:1 RATIO). THE DATA ALSO SHOWED THAT FOR EVERY9 BED SYSTEMS REPORTED FAILING, 1 CHAMBER SYSTEM WAS REPORTED FAILING (9:1 RATIO). THIS DATA SUGGESTS THAT CHAMBER SYSTEM FAILURE MAY BE LESS THAN CONVENTIONAL DISPOSAL BED FAILURE RATES, EVEN THOUGH CHAMBER SYSTEMS ARE HALF THE SIZE OF BED SYSTEMS." The data shows that the chamber bed failure rate may actually be lower than the gravel bed failure rate even though they are half the size. Since they are looking at over 10,000 systems, this becomes statistically significant. Mr. Hoxie concludes, "IN MAhVE, CHAMBER SYSTEMS HA VE BEEN AND CONTINUE TO BE A VALUABLE ALTERNATIVE TO CONVENTIONAL DISPOSAL BEDS. MORE AND MORE DESIGNERS ARE SELECTING CHAMBER SYSTEMS AS THEIR FIRST CHOICE. TO DATE CHAMBER SYSTEMS APPEAR TO HAVE A LOWER FAILURE RATE THAN CONVENTIONAL BED SYSTEMS. CHAMBER SYSTEMS ARE EASIER TO INSPECT AND GENERALLY CAN BE EXPECTED TO HAVE FEWER PROBLEMS AS A RESULT OF POOR CONSTRUCTION PRACTICES" e. This research work was most recently updated in a paper presented at the USEPA International Symposium in Annapolis, Maryland, April of 1989. The study now includes over 23,000 systems, and continues to show even more positive results for chamber systems. Mr. Hoxie states: "THE RATIO OF BEDS TO CHAMBERS FAILURE RATE 1S 5:1 AND THE RATIO OF BEDS TO CHAMBERS INSTALLED IS 2:1. THIS STATISTIC SUGGESTS THAT CHAMBERS DO NOT HAVE A HIGHER INCIDENCE OF FAILURE THAN BED SYSTEMS, ALTHOUGH CHAMBER AREA DESIGNS ARE 50% SMALLER THAN BED SYSTEMS FOR A GIVEN SOIL TYPE." This is an excellent study because it deals with full size real world systems, installed in a variety of soils under normal construction procedures. This is superior to most small scale laboratory studies, since it is a long term analysis of a very large number of actual working systems. The Maine Study along with the Australian research shows conclusively that the INFILTRATOR® chamber system is proven, tested technology. f. E. J. Tyler, J. C. Converse and M. Milter at the University of Wisconsin have been conducting side by side tests on INFILTRATOR® chambers and stone trenches in a silt loam soil and a sandy soil since 1987. Their paperi entitled "Wastewater Infiltration from Chamber and Gravel Systems" was recently completed and was presented at the ASAE conference in December, 1991. In this study, three 6.25 foot long iNFILTRATOR® chamber trenches and three 6.25 foot long by 3.0 foot wide gravel trenches were installed in situ and have been · monitored for 44 months. The paper explains that the systems in the silt loam soil have not yet formed a mature biomat due to the relatively weak effluent produced by the household system. However, even without a biomat, Tyler states on Page 5: "AVERAGE INFILTRATION RATES OF THE THREE REPLICATIONS FOR THE CHAMBER CELLS IS HIGHER THAN FOR THE A VERA GE INFILTRATION RATES FOR THE GRAVEL CELLS. IN DECEMBER 1989, THE AVERAGE INFILTRATION RATE OF THE CHAMBERS WAS 1.3 TIMES THAT OF THE GRAVEL CELLS WHILE IN NOVEMBER 1990 THE INFILTRATION RATES FOR CHAMBERS EXCEEDED THAT OF GRAVEL BY A FACTOR OF 1.7 TIMES." Tyler goes on to explain that in this un-matted period of the study, that there is a great deal of variability among cells. Which, along with a limited number of cells, makes it difficult to prove the differences measured are statistically significant at a very high level of 95% as preferred by statisticians. However, all the differences are significant at a lower confidence level. The above data is statistically significant at about an 80% confidence level. It should be noted that this is one of the first studies in this field to be subjected to extensive statistical analysis to establish that observed differences are also statistically significantly different. Most other research is accepted on face value. Therefore, just because some data points may not show statistical significance at a high confidence level, does not mean the differences are not necessarily real. The mw data shows that, even without a mature biomat, INFILTRATOR® chambers have a higher im~fitrafion rote by a factor of 1.3 to 1.7. The systems in the sandy soil ponded in about a year and have shown seasonal pending since, exhibiting a fully mature biomat. It is clear that the average infiltration rate for INFILTRATOR® chambers is about double that for three foot wide gravel trenches. Tyler states, "THERE IVERE NO SIGNIFICANT DIFFERENCES BETWEEN TREATMENTS FOR THE FIRST MEASUREMENT OF JUNE 1990 USING THE STUDENTS-T TEST AT O. 05, V~HILE THE LAST TWO MEASUREMENTS SHOV/ED SIGNIFICANT DIFFERENCES BETWEEN CHAMBER.AND GRA VEL CELL INFILTRATION RATES USING THE TREATMENT CONTRAST TESTAT O. 01 AND THE STUDENT'S-T TESTAT O. 05 RESPECTIVELY. DURING THE LAST TWO MEASUREMENT PERIODS, CHAMBER INFILTRATION RATES IVERE HIGHER THAN FOR GRAVEL CELLS.' Thus the 2:1 difference between INFILTRATOR® chambers and gravel trenches was statistically significant for the last two measurement periods at a 95% confidence level. The 2:1 ratio of chambers to gravel infiltration rates agrees very well with the research conducted in Western Australia (2.25:1) and field research in Maine where chamber systems are sized at half the size of gravel systems." 2. System .Performance In addition to the tremendous amount of research data supporting the fact that stone masks at least 50% of the soil surface, there is also a tremendous amount of field data that also supports this position. There are over 25,000 iNFILTRATOR® chamber systems around the country installed at our recommended sizing that are performing extremely well. Following is a list of states and jurisdictions that have approved INFILTRATOR® chambers at this sizing, either at the state or county level, ail of which are observing outstanding results: Maine New Hampshire Texas Alabama Colorado Idaho Utah Puerto Rico Michigan (some counties) Georgia (most counties) Wyoming West Virginia New Mexico Washington California (some counties) Kansas (some counties) Some of these states have thousands of systems installed with extraordinary results. Georgia has over 8,000 systems installed. The state recently surveyed the counties to see how the systems were performing. A letter to Infiltrator Systems Inc. from the state of Georgia states: "WE APPRECIATE RECEIVING THE INFORMATION RELATING TO THE iNFILTRATOR SYSTEMS iNSTALLED IN GEORGIA. THE REPORTS FROM OUR LOCAL HEALTH AGENCIES CONFIRMED THE EXCEPTIONAL SHORT TERM SUCCESS RATE OF THE CHAMBER TRENCH SYSTEM WITH A FAILURE RATE OF LESS THAN ONE PERCEN'Z. THESE ARE SYSTEMS WITH REDUCTIONS OF 40% FOR THE STANDARD UNIT (12 inch) AND 50% FOR THE HIGH CAPACITY UNIT (1.5 inch). ' The failure rate is less than 1% which is remarkable considering Georgia has a great deal of clay and installs systems in soils up to 120 rain/inch. There are also over 10,000 systems installed in the states of Maine and New Hampshire in a wide variety of soils. We have one distributor (Eco-Tec) for the states of Maine and New Hampshire who only sell INFILTRATOR® chambers and plastic septic tanks and is very involved in the entire on-site program in Maine. One of the principals, Bruce Johnson, worked for the State Health Department and is past president of the Site Evaluators Association. The failure rate is about 1/2% as stated in a letter to Infiltrator Systems Inc. from Eco-Tec: "SINCE:THE SPRING OF 1987 OUR RECORDS INDICATE THAT APPROXIMATELY 1 O, 000 INFILTRATOR SYSTEMS HA VE BEEN INSTALLED IN THE DVO STATES. OUR RECORDS ALSO SHOW THAT THE FAILURE RATE IS'LESS THAN ONE HALF OF ONE PERCENT (0.5%). ITIS IMPORTANT TO NOTE THAT THESE FAILURES INCLUDE ALL SITUATIONS, NO MATTER WI-MT THE PROBLEM, INCLUDING BUT NOT LIMITED TO: 1.) IMPROPER INSTALLATION BY THE CONTRACTOR (OVER 50% OF FAIL URES) 2.) IMPROPER DESIGN 3.) OWNER ABUSE OF THE SYSTEM, SUCHAS GREASE, GARBAGE GRINDERS, 0 VERLOAD ETC. OUR INVESTIGATIONS OF THE FAILURES REVEALED THAT SIZING REQUIREMENTS AND USE OF THE INFILTRATOR WERE NOT FACTORS IN THE FAILURE'S." When one is making an important decision, as you are here, with respect to stone masking, it is important to look at the overall body of knowledge on the subject and not rely only on one piece of data. The overall body of knowledge on stone masking clearly shows that at least 50% of the surface area is masked and that INFILTRATOR® chamber systems will out perform gravel trenches when sized according to our recommendations. III. MISCONCEPTIONS There is some misconception by a few peol:le concerning the function of gravel/stone. Some have suggested that gravel provides treatment to the effluent. The EPA, in its definitive manual, On-Site Sewage Disposal Systems (Page 224), clearly identifies the critical function of stone as supporting soil, and not in providing any degree oflzeatment. "THE FUNCTION OF THE POROUS MEDIA PLACED BELOW AND AROUND THE DISTRIBUTION PIPE IS FOUR-FOLD. ITS PRIMARY PURPOSES ARE TO SUPPORT THE DISTRIBUTION PIPE AND TO PROVIDE A MEDIA THROUGH WHICH THE WASTEV/ATER CAN FLOW FROM THE DISTRIBUTION PIPE TO REACH THE BOTTOM AND SIDEWALL INFILTRATION AREAS. A SECOND FUNCTION IS TO PROVIDE STORAGE OF PEAK WASTEWATER FLOWS. THIRD, THE MEDIA DISSIPATES ANT ENERGY THAT THE INCOMING WASTEWATER MAY HAVE WHICH COULD ERODE THE INFILTRATIVE SURFACE. FINALLY, THE MEDIA SUPPORTS THE SIDEWALL OF THE EXCAVATION TO PREVENT ITS COLLAPSE. This position is supported by one of the principals in the University of Wisconsin/EPA Small Scale Wastewater Management Program. R/chard Otis, P.E. was one of the investigators in that project, and one of the foremost published authorities in the country. Mr. Otis summarizes what the function of gravel is in a letter dated July 24, 1991: : "IT PROVIDES SUPPORT FOR THE EXCAVATION SIDEWALLS AND BACKFILL TO MAINTAIN THE INTEGRITY OF THE INFILTRATIVE SURFACE, STORAGE FOR PEAK WASTEWATER FLOWS, AND PROTECTS THE DISTRIBUTION PIPE FROM FREEZING AND ROOT PENETRATION." Mr. Otis also deals with the notion that gravel provides some treatment of effluent in a leaching system: "BIOCHEMICAL WASTEWATER TREATMENT REQUIRES TWO BASIC CONDITIONS. FIRST, THE ACTIVE BIOMASS PERFORMING THE TREATMENT MUST BE WELL MIXED WITH THE WASTEWATER. SECOND, SUFFICIENT OXYGEN MUST BE SUPPLIED TO MEET THE OXYGEN DEMAND OF THE BIOMASS IN BIODEGRADING THE WASTEWATER. G_I~AVEL IN A SUBSURFACE INFILTRATION SYSTEM. DOES NOT PROVIDE EITHER OF THESE CONDITIONS. THE WASTEWATER IS NOT EVENLY DISTRIBUTED OVER THE SURFACES OF THE GRAVEL WHERE THE ACTIVE BIOMASS IS ATTACHED. MOST OF THE WAST~EWATER ENTERS THE SYSTEMAT ONE POINT. EVEN WITH PRESSURE DISTRIBUTION, THE DISTRIBUTION IS NOT UNIFORM. ALSO, SUFFICIENT OXYGEN IS NOT SUPPLIED. TRICKLING FILTERS REQUIRE A COUNTER FLOW OF AIR THROUGH THE ROCK TO SUPPLY THE NEEDED OXYGEN. 1N SUBSURFACE SYSTEMS, THE GRAVEL IS NOT VENTED. WHERE VENTS ARE PROVIDED, THEY ARE PASSIVE VENTS THAT ARE INEFFECTIVE BECAUSE THE AIR IS NOT INTRODUCED UNIFORML Y ACROSS THE BASE OF THE GRAVEL. SYSTEMS MAY BE PONDED WHICH PREVENTS THE TRANSFER OF THE OXYGEN WITH TIlE BIOMASS. WITHOUT OXYGEN, TREATMENT IS INEFFICIENT AND INCOMPLETE. TO REQUIRE GRA VEL INA SUBSURFACE INFILTRATION SYSTEM BECA USE OF ANT P RETREA TMENT fT MAY PROVIDE IS UNAPPROPRIATED.' ISI has also discussed this issue with Mr. Steve Dix, Director of the EPA Small Wastewater Flows Clearinghouse. He has provided us with a study summary of efforts at the University of West Virginia that examined biological removals under ideal conditions. In this test, effluent was allowed to nm laterally down the length of stone filled leaching trenches. This would simulate start up conditions of a system. Under this ideal regime, minimal BOD5 and suspended solids removal took place. These facts confirm one basic tenet of the INFILTRATOR* chamber system advantage: _m'avel does not provide treatment in a leaching system IV. SIZING OF CHAMBER SYSTEMS To determine the sizing of an INFILTRATOR® chamber system, one must go back to the £~rst design principle stated in the introduction. The effective exposed surface area of biological clogging mat determines the size of the system with respect to flow. The amount of surface area required for gravel trenches in various soils has been determined empirically over the years, and therefore automatically takes into consideration the effects of gravel masking, dirty or silty gravel, soil compaction, and solids build up in the pore spaces between the stones. Other types of systems, such'as gravel-less pipe and chamber systems, can therefore be sized for equivalent infiltrative surface area by comparing the unmasked areas of the systems. The states code gives the gross area required for gravel systems. If a state uses bottom area only, then compare bottom areas, if they use bottom and sides below the invert, then compare bottom and sides. Some states favor serial distribution with drop boxes, and then consider the entire side and bottom of the trench. The research work presented above clearly shows that the unmasked bottom area of chambers has a 2.25 times higher LTAR than gravel systems and graveMess pipe, and that side wail infiltration rates are about the same. To be conservative and to add an additional safely factor, Infiltrator Systems, recommends using a factor of two (2) rather than 2.25. A comparison of the unmasked infiltrative surface area available for standard INFILTRATOR® chambers, 10" gravel-less pipe and 36" wide gravel trenches with 6" below the invert is shown on the following page, assuming 50% masking for gravel trenches, the INFILTRATOR® chamber sidewall and the I0" gravel-less pipe (Table II). There is no masking of the bottom of the INFILTRATOR® chamber. There is also no compaction from gravel emplacement, or collection of fines in the trench bottom from dirty gravel. Most states use the bottom area, which is 1.5 ft2/ft of unmasked surface area for gravel trenches, and 2.83 ft2/f~ for INFILTRATOR® chambers. There is no well defined bottom area for 10" gravel-less pipe. The only reasonable comparison that can be made for gr. avel-less pipe is the ratio of wetted perimeters below the invert. Therefore, an equal sized INFILTRATOR® trench would be 53% of the length ora gravel trench (1.5 / 2.83 = 0.53) and an equally sized 10" gravel-less pipe system would be 240% of the length ora gravel trench (2.0 / 0.83 = 2.4). This calculation is actually using the wetted surface below the pipe (side & bottom) since the round pipe has no well defined bottom or side, and therefore has no side area in reserve as do gravel trenches and INFILTRATOR® chambers. Thus an equivalently sized INFILTRATOR® chamber system would be 53% of the length of a 3' wide gravel trench system, and a 10" gravel-less pipe system would be 2.4 times longer than a 3' wide gravel trench. Many jurisdictions recognize the improved efficiency of chambers and size the system accordingly. Presently, INFILTRATOR® chambers are approved as an alternative to conventional pipe and gravel leachfields in 35 states, with 17 of those states recognizing the advantages of chambers and using equivalent sizing. V. SUMMARY AND CONCLUSIONS 1. The INFILTRATOR® chamber system uses no new technology. The INFILTRATOR® chamber system uses the same proven, tested, and accepted technology as concrete chamber systems. Since chamber testing tias already been done and systems are widely used, there is no need for additional testing. The Australian data and the University of Wisconsin study establish the appropriate application rates. Due to the lack of masking effect, the trench length of leach fields constructed using Standard INFILTRATOR® chambers can be reduced by 47%, and still provide the same or greater actual infiltrative surface area. 5. The INFILTRATOR® chamber system is not experimental. INFILTRATOR* is a trademark of Infiltrator Systems Inc. © Copyright 1994 Infiltrator Systems Inc. VI. BIBLIOGRAPHY Anderson, J.L.; Machmeier, R.E.; & Gaffon, M.P. perforrrlall~e of Graveless See¢a~e Trenches in Minnesota American Society of Agriculture Engineers (1983). Caldwell Connell Engineers Pry Ltd On-site Wastewater Disposal Systems Final Report, Water Authority of Western Auswalia, Perth. Daniel, T.C.; Bouma, J., Column Studies of Soil CloaaiI!.a in a Slowly Permeable Soil as a Function of Effluent Oualitv. Journal of Environmental Quality, Vol. 3, No.4, (1974) pp. 321-326. Hoxie, Donald Chamber Study letter from Donald Hoxie, 1987. Hoxie, D.C. & Frick, A., "Subsurface Waste Water Disposal Systems Designed in Maine by the Site Evaluation Method: Life Expectancy, System Design,and Land Use Trends," Proceedings, Fourth National Symposium on Individual and Small Community Sewage Treatment, ASAE, (1984). Hoxie, D.C.; Frick, A.F.; Hardcastle, S.E., "Subsurface Waste Water Disposal Systems Designed in Maine by the Site Evaluation Method: Life Expectancy, System Design and Land Use Trends," Proceeding, International Onsite Symposium, 1989. Longest, Henry L.; Mayo, Francis T. On-site Waste Water Treatment and Disposal Systems USEPA Design Manual (pgs. 296 & 298). Longest, Henry L.; Mayo, Francis T. On~site Waste Water Treatment and Disposal Systems USEPA Design Manual (p. 224). Magdoff, F.R. & Bouma, J., The Development of Soil Cloe___ing in Sands Leached with Septic Tank Effluent. Otis, R.J.; Converse, J.C.; Carlisle, B.L.; Witty, J.E. Effluent Distribution. Proceedings of the Second National Home S6wage Treatment Symposium of the ASAE (1977). Otis, Richard J. Function of Gravel in Subsurface Wastewater Infiltration Systems letter to Judd P. Ef'mger from Ayres Assoc., 1991. Schaub, Frank A. U~e/Approval of Concrete Leaching Chambers letter to Infiltrator Systems, Inc. from state of Connecticut, 1987. Siegrist, R.L., Soil Clog,oing Durine Subsurface Wastewater Infiltration as Affected by Effluent Composition and Loadine Rate. Journal of EnvironmentaI Quality, Vol. 16, No 2 (1987) pp. 181- 186. Troyanl Jerry J. Ee_search on On-site Wastewater Disposal in Perth. Australia letter to Jim Nichols, Infiltrator Systems, 1988. Tyler, E.J., Milner, M., Converse, J.C., Wastewater Infiltration from Chamber and Gravel Systems stUdy presented at ASAE Conference, Chicago, IL., December, 199 I. Walters, Dan, Use ~nd Acceptability of Leaching Chambers for Distribution of Septic Tank Effluent for On-ske Systems letter to Infiltrator Systems from West Virginia University, 1987. Q. Q Q 121 The infiltrator'~' Chamber System for Septic Leachfields. SYSTEMS IINIC Standard and High Capacity Infiltrator chambers · provide up to twice the infiltrative capacity of stone and pipe systems. The Infiltrator Chamber System replaces old-fashioned stone and pipe leachfields with patented, high strength polymer chambers. Two chamber sizes are available, Standard and High Capacity, both designed to fit in a standard 36" wide trench. Infiltrator chambers sit directly on the trench bottom. The patented interlocks add strength and latch the chambers together quickly, end to end, so installation takes less than haft the time of a laborious stone and pipe job. Infiltrator chambers may be used for any application that is suitable for stone and pipe. However, by offering greater infiltrative capacity per linear foot, chamber systems can require as little as half the space as conventional systems.* The Infiltrator chamber has an ~ engineered, Iouvered sidewall that allows effluent to pass later- ally into the soil. The angled louvers prevent backfill intrusion into the chamber while 1/4" slots allow lateral leaching. MicroLeaching sidewall Open chamber bottom boosts infiltration. The chamber bottom is completely open, promoting effluent infiltration into the soil with 100% efficiency. The open-bottom area, in combination with the MicroLeaching sidewall, provides maximum infiltra- tive capacity for long-term, trouble-free service. LTAR (Long-Term Acceptance Rate). 0.5 1.0 1.5 2.O This graph demonstrates the dramatic efficiency improvement in LTAR of Infiltrator chambers over stone and'pipe trenches. The LTAR is a measure of the long-term ability of the system to pass efflu- ent into the soil. For example, the High Capacity Infiltrator chamber moves up to twice the effluent of a same-size stone and pipe trench. This efficiency is recogni~:ed by many state and local jurisdictions, who in turn may allow up to 50% shorter trenches. High-density polyethylene construction· Infiltrator chambers are molded of high-density PolyTuff'" polyethylene. This proprietary blend, including recycled resins, is formulated for optimum strength and chemical resistance. It's impervious to wastewater constituents and is stabilized to resist ultraviolet rays. Infiltrator chambers are manufac- tured using an exclusive patented process to assure consistent high quality. AASHTO H-10 and H-20 Icad ratings, Infiltrator chambers have been structurally tested by a registered professional engineer. Both Standard and High Capacity chambers are available with AASHTO ratings of H-10 (16,000 lb/axle with 12" of compacted cover) or H-20 (32,000 lb/axle with 18" of compacted cover). Nominal chamber specifications. Standard High Capacity Chamber Chamber Size, WxLxH 3' x 6-1/4' x 1' 3' x 6-1/4' x 1-1/3' Weight 27 lb. 33 lb. Capacily 77 gal. (10.3 cu. ft.) 122 gal. (16.3 cu. fi.) Subject to state and local regulations Compare the installation and operating advantages. Conventional stone and pipe system Infiltrator Chamber System · Easy assembly and installation by two people. · Labor-intensive, lengthy installation. · Dump truck needed for stone delivery. · Only a backhoe and pickup truck are required. · Stone hauling adds expense and time, and increase~ · Lightweight chambers can be delivered in one soil compaction, pickup truck Icad and hand carried into position. · Stone in trench reduces Long Term Acceptance Rate · Entire trench bottom is open for effluent infiltration by more than 50%. with 100% efficiency. · Heavy traffic across yard and spilted stone mean · There is less regrading, tree damage and landscape there is more site repair needed after installation, repair involved, and no stone cleanup. · System lacks easy inspection and monitoring of · Inspection port is available for easy access to leachfield without digging up the yard. leachfield with no site disruption. · Geotextile required on top of stone. · Solid-topped chambers need no geotextile. o Greater overall cost. · Lower overall cost. Geotextile required to 4" perforated pipe does not give even distribution. Lack of geotextile on trench sidewall may allow soil intrusion. Large storage volume Op~:o~81 accommodates peak Insoettion Port· flows of effluent. Solids build up between stones, limiting infl[t ration backfill intrusion while 1/4' slots allow lateral leaching No stone or geotextile required. Entire bottom of trench is open Ior unobstructed Infiltrator Systems Inc., the industry leader in septic and' stormwater chamber system technology. Four million chambers already in service. In just eight years, the innovative leaching chambers of Infiltrator Systems have drastically changed the technology of on site septic and stormwater disposal. Already, 4 million chambers have been installed in 46 states, Canada and other countries, forming over 75 million square feet of chamber systems with a success rate of 99.5%. And, we're expanding at the rate of 7,500 new systems a month. Environmentally concerned company. Infiltrator Systems devotes over $500,000 a year to research and development, creating new products that operate more and more efficiently and conserve natural resources. Besides using recycled resins, Infiltrator Systems' products take better care of the environment by avoiding the mining, crushing, grad- ing, washing and hauling of stone, as well as the environmental impact a[nd site disruption that stone causes. That's one of o~r "greener" ideas for septic and stormwater disposal that just makes sense. Infiltrator stormwater management. Besides our septic chamber systems, Infiltrator Systems is on the leadi0g edge of the emerging stormwater management field. Our new, underground MaximizerTM Chamber System replaces ponds, large diameter pipe and stone, vaults and dry wells. With its unmatched strength, virtually 100% void volume and convenient clean-out capabilities, the Maximizer Chamber System gives designers better solutions lor retention and detention applications. For more information... Call 1-800-221-4436 for a free copy of the septic installation instructions. SYSTEMS Leading the way in septic and stormwater chamber systems' 4 Business Park Road, PO, Box 768 Old Saybrook, CT 06475 800 221-4436 860 388 6639 FAX 860 388-6810 Distributed By: U S Paten!s: 4 758,661; 5107,401; 5,156,448; 5.336017; 5.401,459; 5,401,116 Canadian Patent 1,329,959 O[her U S Canadian and foreign patents pending Inli[tm!or is a registered trademark and the lo lowing are trademarks of infiltrator Systems Inc: Contour Equa!lzer EQ, Maximizer. MicroLeacning Poi/Tuff Po,verArch, sineW[nde& SnapLock