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URJ Camp Newman- Lescure Engineers Inc.

4088 Porter Creek Rd, Santa Rosacamp newman
Client: Union for Reform Judaism
Project Manager:  Michael Jacob, CGBP
Talia Development, Inc
(707) 246-8845  tdmj@sonic.net

Permitting Agencies: 
North Coast Regional
Water Quality Control Board,
Rachel Prat  (707) 576-2542
Sonoma County Permit & Resource Management Department
James Johnson, REHS (707) 565-1677
Other Consultants – Siegel & Strain, Architects; Bauer & Associates, Geotechnical; Prunuske Chatham, Inc., Environmental; Oberkamper & Associates, Civil; Jim Murphy & Associates, General Contractor.
Status:  Wastewater system construction is nearing completion as of March 2012.  We expect the “throw the switch” in early May when the primary power and backup generator are installed.
Value of LE  Services:  $203,000 including evaluation of existing system, refurbishing the Lift Station, evaluation of the SSDI site, design of the AX-Max/SSDI system and construction services.
Personnel:  Peter J. Lescure, PE and Jason M. Roberts, EIT

Lescure Engineers has engineered the first Orenco AX-Max system in Northern California at Camp Newman in Sonoma County. AX-Max units are a recent advancement of Orenco’s Advantex technology intended for small community systems.  Principal Engineer, Pete Lescure and Jason Roberts, EIT have teamed to deploy one of the largest onsite systems in Sonoma County with sustained peak flows of 20,000 gallons per day (GPD) and occasional peaks to 40,000 GDP.  

Camp Newman dates from the 1950’s where Unified Reformed Judaism (URJ) now hosts summer camps for youth and retreats for adults during the remainder of the year. The camp was constructed by the Lundborg Shipping Lines as a training facility for maritime cooks and stewards. The Camp property on Porter Creek Road, about ten miles east of Santa Rosa, includes over 450 acres. The new wastewater system fulfills the requirements of URJ’s master plan to remodel the entire facility and County Use Permit conditions for increased winter occupancy. Wastewater system construction is nearing completion as of March 2012. Dave Bartle, Project Superintendent for Jim Murphy & Associates, tells us the primary power and backup generators will be installed in April so we expect to “throw the switch” in early May before Camp opens for the Summer.

Our original mission when retained in March 2010 was to upgrade the original wastewater system consisting of a site-built activated sludge plant, a storage pond, and surface spray fields. A package plant had been installed in 2003 to supplant the original activated sludge plant which was then converted to a lift station. The package plant discharges to the spray fields or storage pond depending on weather conditions and runoff potential.  Four spray fields on the east facing slopes of 15 to 30 percent are difficult to manage with limited capacity of only 6 to 12 inches of permeable soil over cemented volcanic tuff.  Surface spray fields have limited winter-time disposal capacity as they cannot be utilized when precipitation threatens to generate contaminated runoff.  Our analysis revealed insufficient disposal and storage capacity to accommodate the current flows per current standards. Increased winter flows anticipated by the Camp’s plans for expanded winter occupancy could not be accommodated without major construction of a second storage pond. The best practical pond site did not have sufficient capacity, and by encroaching on the largest spray field would have reduced disposal capacity.
Faced with that dilemma we started exploring the Camp’s extensive lands for better opportunities.  From the main Camp the east slopes looked formidable with steep faces of numerous rock outcroppings, but we were desperate for opportunities to increase disposal capacity.  Our explorations were rewarded by finding a dense two-acre conifer grove with some hardwood species in a box canyon broadening out to the west at a slope of 15 to 20 percent.  Explorations with a hand auger quickly revealed highly permeable, fine-grained Laniger Loam (LaE) soils, later determined to be up to 12 feet deep.  At that point we saw the opportunity to alter our strategy from enhancing the existing system to replacing it. Deep soils presented the opportunity for subsurface effluent dispersal versus surface spray fields. Subsurface dispersal is not “weather dependent” as surface spray is. Consequently dispersal capacity was immediately increased with a year-around dispersal schedule, and without need for winter effluent storage. 
Jason’s site evaluation with Pearson Excavating of Forestville, and percolation testing in early February 2011 proved out our initial judgment. Geotechnical investigation by Chris Kramer of Bauer Associates, Consulting Engineers also of Forestville demonstrated the landform was not a slide and would remain stable following system installation. A 48 inch Doug Fir and a couple more at 36 inches further attest to long-term stability. Site evaluation revealed no groundwater seepage, even at the bedrock interface at a depth of 12 feet; this in early February following high rainfall.  While this finding was very gratifying we were not surprised. Perc testing yielded rates averaging 1 minute per inch in these deep soils with moderate slopes.   Furthermore the site is at the top of a watershed with only the immediately adjacent slopes contributing runoff. Dense conifer forest ranging from the canyon floor up those slopes attenuates peak precipitation. Forest cover is so dense that we had the owner clear the understory and low limbs before Jason and our Survey Party Chief, Olga Shevchenko, PE could perform the topographic survey.
Given the complex terrain of the conifer grove with slopes varying from 15 to greater than 40 percent, we selected sub-surface drip irrigation (SSDI) technology which provides maximum siting flexibility and dispersal capacity under these challenging conditions. It would also be least disruptive of the dense tree root structure.  As an additional design challenge neither the package plant or the lift station locations were optimal to serve this remote dispersal field. With the need to relocate the package plant while maintaining continuous sewage treatment capacity we opted to install a new Orenco AX-Max treatment system. Nor were we convinced the package plant could consistently provide the effluent quality to support drip irrigation.  Working with Tristan Bounds of Orenco we settled on four AX-Max 28 foot units to provide 20,000 GPD average capacity. As the accompanying photos show, the hillside forest roads are too steep, narrow and curving to transport the largest 42 foot units to the site, which would also have precluded relocating the package plant. The two supplemental 10,000 gallon CSI septic tanks at 32 feet length were a bit more challenging to deliver and set. SBI’s Superintendent, Joe McGee managed those moves with only minor road modifications. 
The entire system is illustrated schematically in Figure 1.  Collected sewage is settled at the 20,000 gallon Lift Station before being pumped 1,875 feet with a 272 foot lift to the two 10,000 gallon secondary septic tanks adjacent the AX-Max units. Altogether these provide two days retention time.  Primary treatment for solids settling and separation from the liquid portion is provided at the Lift Station by primary screening, a settling basin, and a clarifier equipped with a saw-tooth overflow weir to the pump chamber. These elements will limit suspended solids and BOD carryover into secondary treatment in the AX-Max units. Lescure Engineers work scope included modifications to the existing Lift Station for the new system while accommodating ongoing flows to the existing package plant.
We needed to site the AX-Max treatment works immediately below the dispersal field to capture the SSDI backflush by gravity flow without need for additional tankage and pumps.  AX-Max units provide internally plumbed recirculation and discharge chambers, along with the necessary pumps and float switches, in a single package. There is no need for external recirculation or separate discharge tanks. A custom telemetry control panel regulates the recirculation of the AX-Max units as well as the dosing of the sub-surface drip field.  A float switch is provided to signal a high level alarm as well as any system malfunction to the Qualified Service Provider. 

schematic drawing

Each 28 foot unit is designed to filter 5,000 gallons per day average, and 10,000 GPD peak flows for up to one week. The total treatment capacity for the four AX-Max units is 19,075 GPD average and 38,150 GPD peak. Minor capacity reduction from the nominal 20,000 GPD rated capacity is due to missing textile elements displaced by the recirculating and dispersal pumps. With a system design flow of 18,250 gallons per day, the AX-Max units provide a capacity somewhat greater than daily flow, and peak capacity at 2 times the typical peak daily flow. This peak treatment and effluent storage capacity precludes the need for additional flow equalization tankage in front of the units.   
Orenco Advantex AX-MAX units provide biological treatment which consistently reduces Biological Oxygen Demand (BOD) and suspended solids (SS) to secondary standards of less than 30 mg/l BOD and TSS.  Secondary treatment is considered acceptable and supports reliable performance as the industry standard for disposal via sub-surface drip dispersal technology.  Advantex technology typically produces effluent of 10 mg/l or lower BOD & TSS concentrations. Recirculation of nitrified Advantex filtrate to the recirculation chamber will achieve 60 to 70 percent nitrate removal. 

Late in the process we were confronted with a major design issue when more recent 2011 flow data requested by the Regional Board revealed a few daily peaks approaching 40,000 GPD due to unusually high attendance events at the Camp.  Jason and I scrambled in the midst of the permitting process to incorporate 20,000 gallons peak storage. This was in August, approaching the rainy season with a construction schedule calling for completion before Camp would re-open in the Spring.  SBI had already ordered the septic tanks and AX-Max units from Orenco so we had to work within those constraints.  Working with Tristan Bounds and Mike Parker at Orenco, Jason and I learned AX-Max units 3 and 4 could yield 14,000 gallons storage, so we had only to provide 6,000 gallons externally to accommodate treated effluent in the SSDI dosing tanks. With four AX-Max units we had far more than the 80 percent of daily flow for recirc volume.  Placing the SSDI dosing pumps in a supplemental 8,000 gallon tank deeper than the AX-Max provided the “pump submergence” with minimal storage loss. The site was tight to fit it all in, but we had arranged the tankage to optimize gravity flow and still had room to site the 8,000 gallon dose/storage tank without providing additional pumps.  We moved the SSDI discharge pumps out of AX-Max Unit 4 into the 8,000 gallon peak storage tank. 

Dispersal of Advantex effluent is provided by a Geoflow sub-surface drip irrigation field with 20,000 GPD capacity which meets current standards for drip dispersal systems in terms of site slope, soil depth, soil permeability, and setbacks for separation from critical features.  The most critical of these is the standard imposed by the Regional Board to not exceed 10 mg/l nitrate concentration at a distance 100 feet below the field.  We placed one monitoring well above the SSDI field for background, and three downslope.  All are approximately 15 feet deep, seated at  the bedrock interface where we expect saturated flow, if any occurs, to show up.
Sub-surface drip dispersal technology was selected as the preferred method for several reasons:

  • Minimal soil disturbance among the roots of several mature Douglas fir trees.
  • Optimal dispersal patterns to best utilize the soil mantle.
  • Efficient site utilization which would otherwise be limited due to vegetation.
  • Rigid slope limitations among other system types which would otherwise require a different system type for each slope range.
  • Minimal soil disturbance allowing better erosion control.

The Grove Area primary field is divided into four zones and provides 110 percent of the primary dispersal field requirement. The remainder of the Grove Area will provide an additional 210 percent for the required reserve area.

The sub-surface drip dispersal technology was designed and installed per current industry best practices. The primary field is camp newmansubdivided into four zones to allow smaller more serviceable pumps.  Duplex pumps are specified for reliability. Flow meters installed on the discharge pressure main and flush return line will allow measurement of total dispersal volumes minus the backflush volume.  A pressure gauge will be installed in the field to sense whether the pumps are delivering adequate flows, and whether a break has occurred in the dispersal lines causing lower pressure than required to disperse effluent evenly over the entire field.

In the SSDI construction photo the open trenches are on 4 foot centers.  SBI’s crews found they could not keep the trenches open at two foot centers, so had to excavate and install the drip lines in two passes.  They also had to contend with the larger trees left standing by manifolding around them per Geoflow’s recommendation.  Numerous smaller “trash” trees were removed as they were too slender to stand on their own as they had struggled to reach the light under the canopy of the larger trees,  Unlike gravity or even pressure dosed systems, SSDI technology can tolerate the elevation differences between adjacent trenches and maintain even distribution.  Furthermore we had specified Pressure Compensated drip line, versus Classic, as it allowed us to make longer runs with only one central supply manifold.  Due to the length of the runs the flush manifolds had to be placed at the distal ends, rather than looping pairs back to the center.
Thanks to recent advances in onsite treatment and dispersal technology Camp Newman now enjoys a reliable wastewater management system which will cost far less to operate, without the environmental risks their original system posed. With the peak treatment and storage provisions we incorporated, they don’t even have to be concerned about the occasional overflow attendance.  We also owe credit to our forward-looking regulators at the Regional Baord,  Rachel Prat, and Sonoma County PRMD including Bob Herr, James Johnson, Samantha Baunmgartner, and Elsa Frick. Without their foresight and tolerance this system would not have been permitted.  Both systems, Lift Station and the AX-Max/SSDI employ Orenco T-Comm panels with remote monitoring.  Now instead of daily attention to the package treatment plant, and hourly attention to the spray fields, a monthly visit by the Qualified Service Provider will suffice to assure the system is performing as intended.  To view additional construction photos visit Lescure Engineers’ website at www.Lescure-Engineers.com.


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