WSP10774

• File Number: 8271.200
• Description: Colorado River Basin Salinity Control Program - Development and History - UCRB 13a Assessment
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 1/1/1979
• Title: Costs of Wastewater Disposal in Coal Gasification and Oil Shale Processing
• Water Supply Pro - Doc Type: Report/Study

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regenerant che~icals and, in all the cases we have studied, in lowe~ cost.

Al~~ough not a standard procedure today, we expect counter-current regeneration

to become popular. The waste streams for any given jOb are smaller for counter-

current reqeneration than t~ose for co-current regeneration. However, the

difference between the quality of the feed waters is much more than the

difference bet~een regeneration procedures on ~~e same water.

The most

accurate statement of the wastewater is ~~at it is between 6 and 12\ of the
product water and the concentration is about 2.0 to 2.5\ total dissolved solids.
Using counter-current regeneration, a study has been made for a Lurgi
process plant (see Figure 2-2) making 250 x 106 scf/day of pipeline gas drawing
water from the San Juan River and requiring 2930 ga1/min (= 4730 acre-ft/yr =
3 6
1465 x 10 lb/~r) of makeup water. The quality of the San Juan River water and
the specifications for the boiler feed water are given on Table 2-2. The
cheapest ion exchange system found is shown on Figure 2-3. The capi~al and

feed water treatment is
6
about 53-4/10 3tu.

for ~'1is
1. 20/106

system is shown on Table 2-3.

The cost for boiler

operating cost estimate

Btu compared to the cost of pipeline gas of

Details of the waste =rom ~~is system are shown on ~able 2-4.

The low vol~e of waste L, this plant comes partly from the :act ~hat the
source water is of good quality and partly from the fact that excellent ogeraticn
has been assumed.
Ion exchange waste st:eams in coal gasification plants will average
10 Ib wastewater/106 3tu product gas with variations of twofold to one fifth.
For a 250 scf/day pipeline gas plant, this is 100 x 103 lb wastewater/hr (~ 200 gal/mi:t
= 320 acre-ft/yr).

Given the saltiness of ion exchange waste, there are no convenient disposal
trea~ents other than evaporation, or which there are only ewe useful possibilities.
On the one hand the water can be sprayed out for dust control and evaporated
in an uncontrolled manner, at negligible cost. However, it is highly unlikely that
the use of ion exchange wastewater for dust control would be allowed because
of ~'1e ooncerns of runoff and groundwater contamination. Alternately the
water can be impo~~ded and evaporated at costs discussed in Section 2.4. A
forced evaporator, wi~ recovery of distillate, may be used if technically
possible, as discussed in Section 2.4. The particular example shown on Table
2-4 is probably so high in calcium and sulfate that scala formation will ~ake
:::orced evaporation impractical.

(= Sl190/acre-ft) of waste,

pond costing 52.37
6
or 0.3~/10 Stu of product output for a plant

por this particular waste, probable disposal
6
x 10 or about 53.65/1000 gal

would be to a 55 acre lined

operating at a capacity of 90 percent.

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