Opinion: Royal Gorge Sewage or "Squaring the Circle"
January 25 2008, by Bernard Pech
Last November, Royal Gorge LLC (RG) released to Placer County their "Wastewater Treatment and Disposal Alternatives Study". A copy is now available on the SaveSereneLakes site (www.saveserenelakes.org on the "documents" page). Carollo Engineers, who prepared the report for RG, made a well-attended (about 25 members of the public) presentation to the Board of the Donner Summit Public Utilities District (DSPUD- the utility that processes our sewage) at their January meeting. The DSPUD consultant was also present.
First, sewage 101: Getting rid of wastewater (or influent) involves collection, treatment, and disposal. Collection is through pipes and pumps to deliver the wastewater to a treatment plant. The treatment plant uses various filtering, biological, and other high-tech processes to yield "high quality" effluent (the liquid part) and solids. Both products must then be disposed of, a non-trivial task on its own, as the effluent cannot be refined to 100% pure water, and the solids include nasty stuff. The wastewater is characterized by two measures, which dictate the overall sizing of an end-to-end system: its flow (the amount in gallons per day) and its load (the concentration of chemical and solid). Load elements are: total suspended solids (TSS), the biochemical oxygen demand (BOD), ammonia, total nitrogen (TKN), and total phosphorous. Load is also used to rate the effluent quality. There are numerous and ever more stringent federal, state, and local regulations that constrain design and operations.
Our Serene Lakes subdivision gets its water from the Sierra Lakes County Water District (SLCWD). SLCWD has a contract with DSPUD for the processing and disposal of our wastewater, but owns and maintains our collection system. To ensure service to already entitled customers (in Soda Springs, Sugar Bowl as well as the 250 vacant lots at Serene Lakes), and to meet expected occupancy increases over time as well as new, more stringent regulations (California and National Toxic Rule - CTR/NTR - required by 2010), DSPUD has embarked on an expansion of its capacity and an upgrade of its treatment processes. A filing requesting a permit for a 58% increase in maximum daily flow is well under way and proceeding independently from any RG demand. The Board has made it clear that it will not modify its expansion plan in any way until RG gets entitlement, as doing otherwise would only create delays and extra expenses and would be a violation of its fiduciary duties. Today DSPUD discharges its effluent by spraying on a field adjacent and west of the Soda Springs ski lift as a first option, weather permitting (Summer and early Fall), and by dilution into the Yuba River otherwise (Winter). The solids are trucked to Nevada for burial.
The Carollo Engineers Study report, very accessible to a layperson, makes for good reading. We can only encourage Summit residents to read it. At least it would encourage us to watch what we pour into our sinks. Regardless of treatment, it all ends up in our environment. Carelessness can only lead to bills even higher than they are now.
The report first characterizes flow and load for the RG project. The flow depends on the number of equivalent dwelling units (EDUs), water conservation measures (such as toilet technology), and EDU occupancy rates. Peak flow and its duration are important design parameters to balance temporary storage capacity and maximum plant processing capability.
The RG EDUs are estimated at 1,004, as compared to 1,400 currently served by DSPUD. Each RG EDU is projected to be occupied by 4.88 persons with an average discharge of 70 gallons per person. The occupancy rate is assumed to be 75%. The RG flow calculates to an annual average of 0.260 million gallons per day (called the AA flow). 100% occupancy and industry-standard factors of 1.8 and 3.6 are used to calculate max daily flow and max hourly flow. The report then compares these estimates to existing DSPUD measured historical data. The RG AA estimate would more than double 05/06 measured flows. Taking into account occupancy rates and EDUs, the two AA flows are consistent, but two discrepancies are pointed out:
The max daily flow is about 10% lower for RG. This is justified based on better water conservation and less collection pipe leakage in the future new RG development.
The RG AA flow is 20 to 25% lower than the projected water demand calculated by King Engineering. It is stated that it is common for average water demand to exceed wastewater production, as some water demand goes to irrigation, fire fighting, and leakage.
The RG influent load is derived by diluting in the flow volume the "pound per day per person" industry standards for predominantly residential areas of each of the regulated load components. The report finds the calculated concentrations are on the high end of the published data from municipalities, but claims that they are typical for new municipalities which have implemented water conservation. On the other hand, compared to DSPUD historical data, they are lower and this is attributed to higher DSPUD wet weather infiltration and inflow due to old collection pipes.
Having established input parameters, the report develops and analyzes approaches for RG wastewater treatment and effluent disposal. No stone is left unturned. Eight combinations of two treatment alternatives with four effluent disposal strategies are pared down, using mostly common sense, to four potential schemes (as an example, making "green" snow with effluent is set aside - too green for RG?):
1A: Expand the existing DSPUD treatment and effluent disposal capacity to accommodate RG flows.
1D: Same as 1A, except discharge effluent year-around through subsurface irrigation (rather than summer spraying, and winter Yuba River discharge in 1A).
2C: Build a brand new treatment plant for RG flows on RG property, store treated effluent in the winter and spray in the summer.
2D: Same as 2C, but discharge effluent year around through subsurface irrigation.
Subsurface irrigation is similar to a leach field design: the effluent percolates through moderately and highly permeable soils, which continue to remove constituent by filtering and straining action. Primary advantages over spray irrigation are that application can be at a higher rate, resulting in a smaller footprint for the disposal site, and operation can be year around provided that the irrigation pipes are located below the frost layer. The regional regulating agency for surface water discharges (known as CVRWQCB!) has indicated to the engineers that they favor implementing subsurface irrigation as much as possible and that it may be very difficult to permit new water discharges to the South Yuba River.
The spray fields (1A and 2C) or the subsurface irrigation fields (1D and 2D) would be located in two areas: area-1 and area-2. Area-1 (1 x 1/4 mile) is east of and adjacent to Kilborn Lake in the Nevada County section of RG property, a plateau dominating and abutting I-80 by 400 feet. Area-2 (1/2 x 1/4 mile) is a steep slope sandwiched between Crow Nest and the Van Norden Meadow at about 7,000 feet, and draining into the meadow. Both areas would have to be deforested, and possibly fenced against public access. The engineers state that the irrigation pipes would have to be set in trenches four feet deep with gravel bedding.
The 2C storage ponds would be located in area-1 and designed to hold 57 million gallons. Based on the stated footprint of 20 acres, it appears that it would have a depth of about 10 feet. The engineers point out that the storage ponds would fall under the jurisdiction of the Division of Safety of Dams due to their large size, but claim that it may not have to follow dam safety standards, as there are exceptions in the regulations for effluent storage ponds.
The major challenge in expanding the existing treatment plant capacity (1A and 1D) is lack of physical space to fit all the needed equipment and building, and the very rugged nature of the terrain. Furthermore a force-main-pipe would have to be tunneled under highway 80 to bring in influent, and a second one would be needed to bring effluent back to spraying or subsurface irrigation fields. The new RG plant (2C and 2D) would be located in area-1.
Overall, this Carrollo Engineers Waste Water investigation appears to this layperson to be of a much higher quality than the CDM Water Alternatives Study. One appreciates that it does not hide the many great challenges facing RG, in particular:
The already mentioned hostility of regulating agencies with regard to new discharges in the Yuba River.
Preliminary geological investigations that indicate that subsurface irrigation may not be possible in area-1 and area-2 due to the surface proximity of volcanic rock and granite.
The fact that area-1 will accommodate most of the RG effluent spraying but not all. Hence area-2 which drains into the Van Norden meadow would have to be used.
The fact that the existing plant will not be able to accommodate RG flow due to lack of space unless the current sludge and drying bed processes are replaced by a compact Membrane Bioreactor process (MBR).
The difficulty of concurrently operating and expanding the existing plant (1A and 1C) due to terrain characteristics.
The long time (years?) involved in getting permits from the myriad agencies having jurisdiction.
To this writer, the report proves that the Summit environment does not support a way to handle more than double the existing 05-06 DSPUD flow. But RG clearly wants a solution, however unfeasible, and the report attempts to show light at the end of the tunnel. It attempts to downplay some factors as well as trying to provide support for potential RG marketing ploys. Fair enough, after all, RG is paying the consultants bill! But is it reasonable? Here are questions to be answered:
More studies are needed now: the ABCs of any consultant.
The 70 gallons per person per day includes wet weather infiltration and inflow. Is it industry practice?
A storage tank 400 feet above highway I-80 without meeting dam construction standards? What about an earthquake which would spill 60 millions gallon of effluent onto the freeway, or towards Kilborn Lake, Palisade Lake, or Kidd Lake? During the meeting, the DSPUD consultant pointed out that fish are one or two orders of magnitude less tolerant of toxins than humans!
A deforested fenced area (area-2) for spray or subsurface irrigation under a relocated Sugar Bowl Crow Nest ski lift and supporting ski slopes? Well, maybe RG is finally giving up on downhill ski-in, ski-out! And what about drainage into the ecologically sensitive Van Norden meadow?
An influent flow ramp-up projection to help RG justify phased capacity expansion in order to smooth or shift capital expenditure (so called on-time investment), and delay biting the regulatory bullet!
The more egregious claims are that DSPUD and the community at large would derive benefits from the plant expansion alternative. They claim:
First, smoother plant operation due to more even flow. Current DSPUD flow is uneven over time. Even flow is advantageous because bugs die when they have no food, and take time to regenerate when a feast happens. But the statistical distribution of the RG-generated effluent over time would be exactly the same as today (second home EDUs). We would just have more bugs dying and feasting at the same rhythm!
Second, reduction in cost for the on-going DSPUD capacity expansion. Can anybody believe that tying the two projects together would save cost to DPUSD, given the fact that a- the RG project is pushing the envelope of what is reasonable everywhere, not just for wastewater, b- its schedule is totally unpredictable, c- in its present form, it is opposed by 9 out of 10 members of the community as documented by the Donner Summit Area Association Summit Survey.
Third, RG would provide new spray fields to DSPUD needed for its own on-going expansion.
As a community, we need to encourage the DSPUD Board to continue on the track it is on:
Pursue the current planned expansion to serve already entitled customers at whatever pace is justified.
Meet the expansion needs by enhancing the existing treatment processes to release no more effluent by-products into the Yuba River or on the spray field than at present despite the increased flow. Further enhance the plant to meet the new CTR/CNR rule.
Wait until entitlement has been obtained to consider any RG proposal for cost saving to DSPUD.
With regard to waste water, RG is proceeding in the same aggressive way that it has used in all areas: rather than asking DSPUD for the number of EDUs that could be reasonably accommodated by a plant expansion and to constrain their development based on that input, RG is driven by its ill-conceived commitments to investors and seeks the squaring of the circle to meet a demand which is totally unsuited to the Summit environment. When will RG approach the community to design a project that we can all support? One last request to RG: please bring the water study to the same level of professionalism as the Carollo Engineers report.
