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**Brookhaven National Laboratory**

**Water Treatment Plant**

**Recharge Basin Area**

**Facility Environmental Monitoring Report**

**Calendar Year 2001**

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##### April 15, 2002

Prepared by:

D. Paquette and R. Lee

##### Environmental Services Division

###### GW67ER.02

##### 

##### **Brookhaven National Laboratory**

##### **Water Treatment Plant Recharge Basins**

##### **Facility Environmental Monitoring Report**

**Calendar Year 2001**

***Summary of Results**: Routine monitoring of Water Treatment Plant
discharges to Recharge Basin HX indicate that backwashed water from the
plant's filters contains mostly insoluble iron. Furthermore, analysis of
groundwater samples indicates that routine discharges of the backwash
water to Basin HX have not impacted groundwater quality in the Water
Treatment Plant area.*

###### Background

The BNL Water Treatment Plant (WTP) is designed to remove naturally
occurring iron from groundwater pumped from drinking water supply wells
4, 6 and 7. The WTP uses a conventional lime softening process for iron
removal with air stripping for volatile organic compound removal.
Precipitated iron is removed using multi-media (sand and anthracite
coal) filters, which require routine backwashing. When the plant is in
full operation, the filters are backwashed one to two times a day. The
effluent from this backwash process is discharged into Recharge Basin
HX, located adjacent to the plant. (Note Basin HX is divided into east
and west sections that are separated by a sand berm.) The majority of
the water percolates through the sand below the basin, but an iron
residue is left at the bottom of the basins. Typically over several
years of use, the iron residue builds up to an extent that prevents
proper percolation of the backwash water, and creating a potential
overflow condition. To restore proper percolation, the iron residue is
periodically scraped off the basin floors.

Until February 2002, discharges of the WTP backwash water to the basins
were monitored as part of BNL's State Pollutant Discharge Elimination
System (SPDES) program (SPDES Outfall 007). Because the discharges
typically have iron concentrations in excess of the State discharge
limit to groundwater of 0.6 mg/L, the New York State Department of
Environmental Conservation (NYSDEC) had also required BNL to determine
whether the backwash effluent has a detrimental effect on groundwater
quality before a variance could be issued. In 1992, BNL installed five
monitoring wells. These wells have been routinely monitored since that
time. Additionally, the SPDES permit had required that samples of the
backwash water be collected monthly, and analyzed for soluble and
insoluble iron

###### Environmental Monitoring Program

In response to a 1992 request by the NYSDEC, BNL established a
groundwater monitoring program at the Water Treatment Plant to evaluate
potential impacts from plant discharges to nearby recharge basins. Until
February 2002, Water Treatment Plant discharges to the recharge basins
were monitored as part of BNL's SPDES program. The groundwater and SPDES
monitoring programs for the Water Treatment Plant recharge basins are
described in the BNL Environmental Monitoring Plan (Daum *et al*. 2000;
BNL, 2001).

###### Monitoring Results

**SPDES Monitoring**

To determine if the discharge of iron-sludge generated from the
lime-softening process would potentially impact groundwater quality, the
backwash water from the WTP sand filters was monitored monthly for
dissolved and suspended iron. In the mid 1990s, BNL attempted to collect
six months of operational data to demonstrate to the NYSDEC that
discharges to Basin HX were not impacting groundwater quality. However,
due to the infrequent use of the WTP from 1995 to 2000, samples of
filter backwash water were not collected on a routine basis. In April
2000, water treatment operations at the plant became more routine when
the Laboratory switched to supply wells 4, 6 and 7 to obtain most of the
water (\~85%) needed for daily consumption. Analytical results of
backwash samples have been reported monthly since April 2000. Review of
the analytical results for the backwash samples reported in the
Discharge Monitoring Reports for 2001 showed the total concentration of
iron to be as high as 624 mg/L. The dissolved fraction accounted for
approximately 1.8 mg/L of this total.

Based upon a review of the discharge monitoring data, in February 2002
the NYSDEC agreed to discontinue the requirements for monitoring iron
levels in the discharges to Basin HX (NYSDEC, 2002). BNL will continue
to monitor flow and pH levels on a monthly basis.

**Groundwater Monitoring**

The groundwater monitoring wells in the WTP's recharge basin area were
sampled in June 2001. Analytical results indicate that anions and metals
(including iron) concentrations were below the applicable New York State
Ambient Water Quality Standards (NYS AWQS) and were consistent with
established background levels for Long Island (Tables 1 and 2). Since
the beginning of the groundwater monitoring program in 1992, iron has
rarely been detected above the typical detection limit of 0.075 mg/L in
groundwater near Basin HX, and has never exceeded the 0.3 mg/L water
quality standard.

**Future Monitoring Actions**

The following actions will occur during CY 2002:

-   Based upon BNL's updated SPDES permit, BNL will discontinue
    monitoring iron levels in WTP discharges to Basin HX starting in
    February 2002.

-   Concurrent with the termination of monitoring iron levels in WTP
    discharges to Basin HX, BNL will discontinue the collection of
    groundwater samples from wells located near the basin. BNL will
    maintain the wells for the collection of water level measurements
    and for potential future collection of water samples to periodically
    verify water quality.

**References**

BNL, 2001. Brookhaven National Laboratory Environmental Monitoring Plan,
CY 2001 Update (January 2001). BNL-52584 Update.

Daum, M., Dorsch, W., Fry, J., Green, T., Lee, R., Naidu, J., Paquette,
D., Scarpitta, S., and Schroeder, G., 2000. Brookhaven National
Laboratory, Environmental Monitoring Plan 2000 (March 31, 2000).
BNL-52584.

NYSDEC, 2002. Letter from M.C. Carrara (NYSDEC) to M. Holland (USDOE)
titled: NYSDEC Permit #1-4722-00032/00072; SPDES Facility #NY-0005835.
Dated February 8, 2002.

**BNL Facility Environmental Monitoring Report**

**Water Treatment Plant Recharge Basin Area**

**Groundwater Monitoring Program**

**Water Quality Results for CY 2001**

**Table 1**

+----------+---------+---------------+---------------+---------------+
| **Well** | *       | **Chlorides** | **Sulfates**  | **Nitrate**   |
|          | *Sample |               |               |               |
|          | P       | **(mg/L)**    | **(mg/L)**    | **(mg/L)**    |
|          | eriod** |               |               |               |
+----------+---------+---------------+---------------+---------------+
| 0        | NS      | \--           | \--           | \--           |
| 63-01(a) |         |               |               |               |
+----------+---------+---------------+---------------+---------------+
| 063-02   | NS      | \--           | \--           | \--           |
| (a)      |         |               |               |               |
+----------+---------+---------------+---------------+---------------+
| 063-03   | June    | 21.0          | 11.8          | \<1.0         |
+----------+---------+---------------+---------------+---------------+
| 073-01   | June    | 21.7          | 9.4           | \<1.0         |
+----------+---------+---------------+---------------+---------------+
| 073-02   | June    | 20.2          | 9.4           | \<1.0         |
+----------+---------+---------------+---------------+---------------+
| Typical  |         | 4.0           | 4.0           | 1.0           |
| MDL      |         |               |               |               |
+----------+---------+---------------+---------------+---------------+
| NYSAWQS  |         | 250           | 250           | 10            |
+----------+---------+---------------+---------------+---------------+

(a): Well is located upgradient of the recharge basins.

MDL: Minimum Detection Limit.

NS: Upgradient wells not sampled because background values have already
been established.

**BNL Facility Environmental Report**

**Water Treatment Plant Recharge Basin Area**

**Groundwater Monitoring Program**

**Metals Analytical Results for CY 2001**

**Table 2**

<table>
<colgroup>
<col style="width: 9%" />
<col style="width: 7%" />
<col style="width: 7%" />
<col style="width: 7%" />
<col style="width: 7%" />
<col style="width: 7%" />
<col style="width: 7%" />
<col style="width: 7%" />
<col style="width: 7%" />
<col style="width: 7%" />
<col style="width: 7%" />
<col style="width: 7%" />
<col style="width: 7%" />
</colgroup>
<tbody>
<tr class="odd">
<td><strong>Well</strong></td>
<td><strong>Sample Period</strong></td>
<td><p><strong>Ag</strong></p>
<p><strong>(mg/L)</strong></p></td>
<td><p><strong>Al</strong></p>
<p><strong>(mg/L)</strong></p></td>
<td><p><strong>Cd</strong></p>
<p><strong>(mg/L)</strong></p></td>
<td><p><strong>Cr</strong></p>
<p><strong>(mg/L)</strong></p></td>
<td><p><strong>Cu</strong></p>
<p><strong>(mg/L)</strong></p></td>
<td><p><strong>Fe</strong></p>
<p><strong>(mg/L)</strong></p></td>
<td><p><strong>Hg</strong></p>
<p><strong>(mg/L)</strong></p></td>
<td><p><strong>Mn</strong></p>
<p><strong>(mg/L)</strong></p></td>
<td><p><strong>Na</strong></p>
<p><strong>(mg/L)</strong></p></td>
<td><p><strong>Pb</strong></p>
<p><strong>(mg/L)</strong></p></td>
<td><p><strong>Zn</strong></p>
<p><strong>(mg/L)</strong></p></td>
</tr>
<tr class="even">
<td>063-01(a)</td>
<td>NS</td>
<td>--</td>
<td>--</td>
<td>--</td>
<td>--</td>
<td>--</td>
<td>--</td>
<td>--</td>
<td>--</td>
<td>--</td>
<td>--</td>
<td>--</td>
</tr>
<tr class="odd">
<td>063-02 (a)</td>
<td>NS</td>
<td>--</td>
<td>--</td>
<td>--</td>
<td>--</td>
<td>--</td>
<td>--</td>
<td>--</td>
<td>--</td>
<td>--</td>
<td>--</td>
<td>--</td>
</tr>
<tr class="even">
<td>063-03</td>
<td>June</td>
<td>&lt;0.001</td>
<td>0.011</td>
<td>&lt;0.001</td>
<td>&lt;0.001</td>
<td>&lt;0.002</td>
<td>&lt;0.075</td>
<td>&lt;0.0001</td>
<td>&lt;0.002</td>
<td>12.5</td>
<td>&lt;0.0013</td>
<td>&lt;0.004</td>
</tr>
<tr class="odd">
<td>073-01</td>
<td>June</td>
<td>&lt;0.001</td>
<td>0.009</td>
<td>&lt;0.001</td>
<td>&lt;0.001</td>
<td>0.006</td>
<td>&lt;0.075</td>
<td>&lt;0.0001</td>
<td>&lt;0.002</td>
<td>12.8</td>
<td>&lt;0.0013</td>
<td>&lt;0.004</td>
</tr>
<tr class="even">
<td>073-02</td>
<td>June</td>
<td>&lt;0.001</td>
<td>0.006 J</td>
<td>&lt;0.001</td>
<td>&lt;0.001</td>
<td>&lt;0.002</td>
<td>&lt;0.075</td>
<td>&lt;0.0001</td>
<td>&lt;0.002</td>
<td>12.4</td>
<td>&lt;0.0013</td>
<td>&lt;0.004</td>
</tr>
<tr class="odd">
<td>Typical MDL</td>
<td></td>
<td>0.001</td>
<td>0.002</td>
<td>0.001</td>
<td>0.001</td>
<td>0.002</td>
<td>0.075</td>
<td>0.0002</td>
<td>0.002</td>
<td>1.0</td>
<td>0.001</td>
<td>0.004</td>
</tr>
<tr class="even">
<td>NYSAWQS</td>
<td></td>
<td>0.05</td>
<td>0.1</td>
<td>0.01</td>
<td>0.05</td>
<td>0.2</td>
<td>0.3</td>
<td>0.0007</td>
<td>0.3</td>
<td>20</td>
<td>0.025</td>
<td>0.3</td>
</tr>
</tbody>
</table>

(a): Well is located immediately upgradient of the recharge basins.

Note: Primary potential contaminants shown. Other metals were analyzed
for -- see database for complete data set

MDL: Minimum Detection Limit

NS: Upgradient wells not sampled because background values have already
been established.

J: Estimated value.

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