(GP/GT) for Additional Water Supply in the Lower Rio Grande

ill-35
fill - Based on the above mentioned projections, the hydraulic energy available via a Pelton Wheel arrangement
is significant, but probably not adequate to serve as the sole source of energy production. This
arrangement should, therefore, be utilized as a supplementary rather than predominant, energy form. As
regards the status of the technology, based on information received from Canyon Industries{7}, the
magnitude of the energy source is sufficient to be incorporated into a commercially available
Geopressured hydroelectric project, using a Pelton-type turbine. However, a number of uncertainties
including flashing and cavitation, Le. related primarily to the chemical makeup of the Geopressured fluid,
require further study.
In summary E(G) should be relied on as the predominant and definitely workable energy form to power a significantly
sized desalination plant, and its use easily merits the highest ranking from the perspective of technical feasibility. In
contrast, at the present time, consideration should be given to the use of E(B) and E(P) as sources supplementary to E(G)
until specific technical uncertainties have been resolved.
Step 2 - Economic Feasibility
Process Types
Alternatives C and D - As in the case of technical feasibility, the primary basis for a comparison of economic feasibility
between EDR and RO, as applied to the Group 1-4 brackish ground waters from relatively shallow aquifers is the
aforementioned preliminary evaluation prepared by Mr. Eugene Reahl of lonies, Inc., and enclosed herein as Appendix
G. Pages 3-6 of the evaluation provide information comparing EDR with RO from the prespective of feedwater
requirements in relation to product water (Le. percent water recovery) and also the brine streams for the Group 1-4
waters.
The remaining pages of the evaluation are devoted to a comparison between the capital and O&M costs and energy
requirements for a 1 MGD RO based system and those for a comparably sized EDR based system for each Group of
waters. A review of the comparative costs data indicates relatively insignificant cost differentials and energy requirements
as among the four Groups. Accordingly, since the Group 1 waters appear to be the most prevalent in the study area and
Mr. Reah\'s evaluation provides the most detail for this Group, a summary of the comparative economic evaluation for
this Group, based on an assumed cost of SO.081KWH for electrical power, is presented as follows:
Capital Cost per
1 MGD module of
product water
O&M costs!
1000 gallons of
500 ppm product water
Electrical Energy Consumotion
a. KWHr!lOOO gallon product water
b. KWHr/dayl 1 mgd product water
RO Based System
(with blend)
S665,OOO
SO.50
3.4
3400
EDR Based System
(no blend)
S940,OOO
SO.563
4.4
4400