WSP10013

• File Number: 8040.500
• Description: Section D General Studies - Ground Water
• Date: 7/1/1999
• Author: SDU, BOR, USEPA,USGA
• Title: High Plains States Ground Water Publications - Huron Recharge Demonstration Project Summary
• Water Supply Pro - Doc Type: Report/Study

A comparison of the native groundwater quality and the injectate is shown in table 1. The
data collected revealed several contrasts between the injectate water and native ground- ..
water. The groundwater is dominated by sodium, sulfate, and bicarbonate and has low ..
dissolved oxygen and pH and high iron and manganese relative to the injectate. Without
chemical interactions, the injectate water would improve the aquifer water quality.
However, the high pH and dissolved oxygen of the injectate water could hypothetically
create calcium carbonate and iron precipitation at the mixing zone interface in the aquifer.
These conditions often cause plugging and pumping head loss that can reduce injection
efficiency.

Table 1.-Comparison of injectate and native groundwater quality

Parameter

Groundwater

Injectate

Dissolved oxygen, mg/L 0,
Temperature, oCelsius
pH, units
ORP, mV
pI:
Alkalinity, mg/L as CaCO,
Calcium, mg/L
Magnesium, mg/L
Sodium, mg/L
Iron, mg/L
Manganese, mg/L
Sulfate, mg/L
Chloride, mg/L

0.0
11.0
7.45
-100
-1.775
475
45.0
12.2
325
2.1
0.23
340.0
37.0

7.0
22.0
8.8
145
2.477
45
42.0
12.1
100
0.07
0.01
275.0
65.0

.

To delineate the movement of the recharge water during recharge, clustered wells were
monitored for selected water quality properties and constituents. Clustered wells were
used to monitor water quality properties at the top, middle, and bottom of the aquifer and
to provide information on the movement and stratification of the recharge water. Water
quality properties used to track recharge water were pH, dissolved oxygen, iron, sodium,
alkalinity, sulfate, specific conductance, oxidation-reduction potential, dissolved solids, and
hardness: these pa-rameters were selected based on previous analyses of water quality in
the aquifer and the water from the Huron water treatment plant.

Batch and column experiments were conducted to evaluate the possible interactions
between injectate water and native groundwater and between the injectate water and the
aquifer formation. In the batch experiments, various ratios of injectate water and ground-
water were mixed, and analyses of alkalinity, dissolved oxygen, iron, manganese,
magnesium, calcium, and several anions were conducted for 5 consecutive days. The
analyses showed no measurable change in manganese, calcium, or magnesium
concentrations, indicating that precipitation of these ions did not occur. Batch experiments
were also conducted to determine whether polyphosphate compounds that are conunonly
used in water treatment would sequester iron encountered in the aquifer and effectively
prevent iron oxidation in the mixed waters. The results of these studies indicated that the

.

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