How the design of Sedimentation Basin #2 may create a problem for Synagro's proposed crap factory on Grand Central Sanitary Landfill's site in Plainfield Township

The optimistically named* Slate Belt Heat Recovery Center or "SBHRC" that Synagro proposes to build in Plainfield Township is situated within 10 feet of a freshwater pond that is also being used as a sedimentation basin as part of Grand Central's landfill operation.  The sedimentation basin will have to be partially filled to make room for the Synagro facility, which is proposed to be built on a postage stamp-sized piece of land.

*Grand Central's advertising states the landfill is forecast to close in 2030.  After that, there will be no heat to recover from burning landfill gas - Synagro will burn 100% natural gas after closure of the landfill.

Proposed Synagro plant above basin (dashed blue line), landfill below

Sedimentation basins are designed to let sediment settle out, and the remaining clean(er) water flows away through an outlet and spillway.  In the case of Sedimentation Basin #2, there is no outlet because this is a former quarry and the water in the basin is exchanged through the walls with groundwater.  As a result, the water level in the basin rises and falls with the groundwater level in the earth surrounding the basin.

One of the regulations for sedimentation basins is that the bottom of the basin be above the level of neighboring wetlands, and perennial streams.  This rule was enacted after Sedimentation Basin #2 was approved.  Now it is proposed to modify the basin, and it is quite possible the new rule applies.  In DEP's deficiency letter, this is one of the deficiencies noted..

Let's look at a profile of Sedimentation Basin #2.  The diagram was submitted by Synagro, and is marked up to emphasize the location of Little Bushkill Creek, and the fact that the water level in the basin goes up and down as it exchanges water with the surrounding water table.  There is no other outlet.

It is obvious from the diagram that the bottom of the current sedimentation basin is about 75 feet below the creek headwaters, and the proposed basin bottom (black dashed line) after partially filling (which will require a permit now that a waiver is no longer guaranteed) is about 30 feet below the creek headwaters.

It will be interesting to see how this plays out.  On paper, it looks like a problem to a casual observer since the bottom of the basin is below the creek, and it should be above.

Of note in this diagram is the word "APPROX" used liberally.  Synagro has no idea exactly what the contour is of the existing basin, since they have refused to do a hydrogeological study.  There is no guarantee the existing bottom is at 620 feet - it could be far deeper since the quarry depth was several hundred feet at one time.  Under the surface of the water in the basin, no one really knows what is happening - including DEP.

Current and proposed bottom of sedimentation basin is below Little Bushkill Creek tributary elevation

Sec 7.1 of DEP Erosion and Sediment Control BMP's manual

PA DEP finds significant deficiencies in Grand Central Sanitary Landfill permit modification application for Plainfield Township Synagro crap factory SBHRC

On March 22, 2019 an environmental engineer in the waste management department of the PA Department of Environmental Protection issued a 9-page deficiencies letter in response to the application by Grand Central Sanitary Landfill to modify its permit to add Synagro's proposed shit bakery to operations permitted on site.  This engineer is in the same division as Roger Bellas, who issued an ill-conceived letter that was later retracted, in which Bellas indicated that carte blanche would be extended to Synagro to modify Sedimentation Basin #2 (formerly Doney Quarry #2, and now a pond) as it pleases.  Plainfield Township does not believe that the engineering that should have been done for the DEP to approve the existing Sedimentation Basin #2 back in 2008 was in fact done, and also does not believe that it was constructed as a sedimentation basin.  For example it has no outlet.  A sedimentation basin should allow sediment to be collected, and the liquid runs off.  That does not happen in the pond that exists.  An appeal of Bellas' letter resulted in its subsequent retraction.

Simply put, the DEP is not impressed with the enviromental aspects of the permit modification application, especially in regards to Sedimentation Basin #2.  For over a year, Synagro's engineer EarthRes has insisted that since the pond was approved to be a sedimentation basin, and because DEP issued a waiver in the past to fill part of it in (modify it), it should not be treated as a pond.  Bellas' letter indicated the water body would again be granted a waiver, and Synagro and Waste Management have assumed they would waltz (pun intended) through the pearly gates and grasp the elusive Golden Turd (see sidebar for how this project is likely worth millions a year to each).

The holy grail for Waste Managment and Syangro - the Golden Turd
(While Green Knights and the community reaps diarrhea in the form of a maximum $100k a year)

Not so fast - in its deficiency letter DEP is saying "OK, it is a sedimentation basin - show us you meet the requirements for a sedimentatuion basin and oh, by the way the requirements for them are more stringent now."  DEP appears to be coming around to the township's position, and this has resulted in some interesting deficiencies.

The letter is below.  Here are some highlights of the deficiencies noted:

• The maximum tributary area for a sediment trap is 5 acres, but the proposal is for 24 acres.
• The discharge capacity of the sedimentation basin is not provided.  The principal spillway must convey the discharge from a 10-year storm. (note the current basin has no discharge)
• No dewatering device is proposed for the basin, but it is required to state the 4 to 7 day dewatering times.
• The length and width of the bottom of Sedimentation Basin #2 are stated as "unknown" in the application (lol).
• Show how the bottom of Sedimentation Basin is above the high water table, surrounding wetlands, and perennial streams (lol - the bottom is probably 90' below these). (!)
• Sedimentation Basin #2 should have an outlet.
• Sedimentation Basin #2 can not both pre-treat runoff and have runoff.
• Flow length could not be calulated since there is no outlet structure.
• Length and width of principal spillway are not specified.
• There is no Post Construction Stormwater Management (PCSM) plan provided.
• Neither the Little Bushkill or Waltz Creek are mentioned as surface waters that may receive runoff for the proposed project in the stormwater management plan or stormwater narrative. (!)
• The application does not mention or contain calculations that address increases in water volume and impacts on water quality of the project. (!)
• It appears the sedimentation basin is actually a detention pond, and if so it should take more than 24 hours but less than 72 hours to drain. (DEP appears to be asking "what exactly is Sedimentation Basin #2"?!)
• The peak stormwater runoff rates shown only cover tributaries to Sedimentation Basin #2 - all drainage from disturbed areas must be shown, including those that bypass the basin.
• Flow rates for the emergency spillway are not shown.
• Insufficient freeboard is provided from the 100-year storm to the invert of the emergency spillway.
• The DEP is not aware of any data that would allow an evaluation of the connection between the sedimentation basin and the Little Bushkill and Waltz creeks, and how the proposed modification of the basin might impact these water bodies. (!)

Synagro has 60 business days from the date of the letter (June 17) to respond and address each of the deficiencies noted in the letter.  There are some very serious deficiencies in this list - Synagro may very soon rue the day that it chose to attempt to take advantage of the DEP having approved the quarry pond as a sedimentation basin some 10 years ago, since sedimentation basins have requirements and current standards are that the basin bottom be about 90' higher than it is.  At the February 21, 2019 planning commission review, Waste Management representative Scott Perin made a big production at the podium about how Sedimentation Basin #2 was approved in 2008, and any appeal period for that approval has expired.  What he didn't appreciate is that approval is not what matters - a modification is now proposed and current standards apply as well as the design and construction criteria that DEP did not address in granting approval in 2008.  Mr. Bellas does not get to wave his magic shit wand and make everything ok to move forwards.

Whoa daddy - 90', up!  Get the big crane out, and let's get started lifting this quarry out of the ground.

Note that this letter pertains to only one of four permit applications.  The others are NPDES, air quality and the facility permit for the Synagro bakery.   This is the first application that is known to have received a technical deficiencies letter.

Synagro Grand Central Sanitary Landfill DEP Technical Deficiency Letter Permit Modification SBHRC on Scribd