The State of California Department of Health Services (DHS) has developed draft regulations addressing
groundwater recharge with reclaimed water. In recognition of the need to remove, or reduce the
concentrations of health-significant organic constituents that may be present in municipal wastewater,
DHS has selected total organic carbon (TOC) as a parameter to be monitored in the reclaimed water. The
intent of the TOC requirement is to limit the TOC of wastewater origin in the extracted water to a
maximum of 1 mg/L. Dilution, either at the point of recharge or in the aquifer, is also required to limit
the maximum reclaimed water contribution to 50% unless methodology is identified and demonstrated to
be as effective as a 1:1 dilution. Two questions central to the dilution requirement issue are explored in
this paper. Can reclaimed water having less than or equal to 1 mg/L TOC be reliably produced? Does meeting a TOC limit
of less than or equal to 1 mg/L in the reclaimed water at the point of recharge provide a level of health protection equivalent
to meeting a TOC limit of less than or equal to 2 mg/L in the reclaimed water and blending it 1:1 with water of non-wastewater
origin? The purpose of this paper is not to advocate elimination of the dilution requirement in the draft
groundwater recharge regulations for reclaimed water used for indirect potable reuse. The intent is to
suggest addition of an alternative method of treatment that could be included in the regulations to
produce reclaimed water that, from a health standpoint, is at least equivalent to blended water having the
same TOC concentration of wastewater origin. Includes 43 references, tables.
| Edition : | Vol. - No. |
| File Size : | 1
file
, 250 KB |
| Note : | This product is unavailable in Ukraine, Russia, Belarus |
| Number of Pages : | 19 |
| Published : | 01/01/2000 |
