PROPOSED RULEMAKING
[25 PA. CODE CH. 95]
Wastewater Treatment Requirements
[39 Pa.B. 6467]
PA
Bulletin, Doc. No. 09-2065
http://www.pabulletin.com/secure/data/vol39/39-45/2065.html
[Saturday, November 7, 2009]
The Environmental Quality Board (Board) proposes to
amend 25 Pa. Code Chapter 95 (relating to Wastewater Treatment
Requirements). The proposed amendments include the elimination of a
redundant provision, the recognition of applicable TMDL
requirements, and the establishment of new effluent standards for
new sources of wastewaters containing high Total Dissolved Solids
(TDS) concentrations.
The proposal was adopted by the Board at its meeting
of August 18, 2009.
Code of 1929 (71 P. S. §§ 510-7 and 510-20).
D. Background and Purpose
Total dissolved solids (TDS) is comprised of
inorganic salts, organic matter and other dissolved materials in
water. They can be naturally present in water or the result of
runoff, mining or industrial or municipal treatment of water. TDS
contain minerals and organic molecules that provide benefits such as
nutrients, but also may contain contaminants such as toxic metals
and organic pollutants. However, the benefits noted are when
considered in moderation, which is likely not the case in a high TDS
discharge. The concentration and composition of TDS in natural
waters is determined by the geology of the drainage, atmospheric
precipitation and the water balance (evaporation/precipitation).
TDS causes toxicity to water bodies through increases
in salinity, changes in the ionic composition of the water, and
toxicity of individual ions. The composition of specific ions
determines toxicity of elevated TDS in natural waters. Also, as the
hardness increases, TDS toxicity may decrease. The major concern
associated with high TDS concentrations relates to direct effects of
increased salinity on the health of aquatic organisms.
Water quality analyses performed for the major
watersheds of this Commonwealth to date, show that many of the
rivers and streams of this Commonwealth have a very limited ability
to assimilate additional TDS, sulfates and chlorides. This
phenomenon was most evident during the fall of 2008, when actual
water quality issues related to these parameters emerged in the
Monongahela River basin. While river flows reached seasonal lows,
the concentrations of TDS and sulfates in the river increased to
historic highs, exceeding the water quality standards at all of the
17 Potable Water Supply intakes from the border with West Virginia
to Pittsburgh. Exceedances of water quality standards for TDS and
sulfate persisted in the river through November and December of
2008. Elevated chloride levels were observed on at least one major
tributary—South Fork Tenmile Creek—and for the first time, elevated
bromide levels were observed in these streams.
During this period, several environmental agencies
performed studies on the effects of TDS, sulfate and chloride
discharges on the Monongahela and some of its tributaries. A study
conducted by the Environmental Protection Agency (EPA), the
Department and the Allegheny County Health Department (ACHD) also
identified bromides as a key parameter of concern in these waters.
The study concluded that a high percentage of the Disinfection
By-Products (DBPs) being formed in the drinking water systems were
brominated DBPs, which pose a greater health risk than chlorinated
DBPs; and, subsequent formation of brominated DBPs increases overall
DBP concentrations, specifically trihalomethanes (THMs). The study
also concluded that based on the speciation there appears to be a
strong correlation between THM formation and elevated source water
bromide concentrations in the Monongahela River. As a result, the 17
potable water supply intakes on the Monongahela River are subject to
higher levels of the more toxic brominated DBPs, creating increased
risks of bladder cancer to their consumers.
Several studies on the potential impacts to aquatic
life from these large TDS discharges were also conducted on major
tributaries flowing into the Monongahela River in Greene County, PA.
Each of these studies documents the adverse effects of discharges of
TDS, sulfates and chlorides on the aquatic communities in these
receiving streams. The former concludes that there is a high
abundance of halophilic (salt-loving) organisms downstream from the
discharges of TDS and chlorides and a clear transition of fresh
water organisms to brackish water organisms in the receiving stream
from points above the discharge to points below. It is evident from
this study that increases in salinity have caused a shift in biotic
communities.
The Monongahela River Watershed is being adversely
impacted by TDS discharges and many points in the watershed are
already impaired, with TDS, sulfates and chlorides as the cause.
Although the Monongahela has received the most
attention, it is not an anomalous situation. The Department has
studied the results of stream monitoring and has conducted an
analysis on the water quality of the Beaver River in western
Pennsylvania. These results show upward trends in TDS
concentrations. The Department has also conducted similar studies on
the Shenango and Neshannock Rivers, with similar upward trends in
TDS concentrations.
In addition, watershed analyses conducted by the
Department of the West Branch of the Susquehanna River and the
Moshannon River Watersheds have documented that they are also
severely limited in the capacity to assimilate new loads of TDS and
sulfates. The Department has received several permit applications in
these areas where the permits will not be able to be issued with
limits greater than the water quality standards due to the high
background concentrations of TDS.
The surveys, analyses and studies referenced
establish that the extent of existing and potential pollution from
TDS, sulfates and chlorides is widespread. The Department is
constrained from approving any significant portion of the pending
proposals and applications for new sources of discharge high-TDS
wastewater that include sulfates and chlorides, and still protect
the quality of streams in this Commonwealth.
The existing practice for high TDS wastewaters is the
removal of heavy metals, but currently no treatment exists for TDS,
sulfates and chlorides, other than dilution. As documented by the
rising levels of TDS in the waters of this Commonwealth, dilution
can no longer be considered adequate treatment for high TDS
wastewaters.
The Clean Streams Law (35 P. S. §§ 691.1—691.1001)
delegates the authority to preserve and improve the purity of its
waters and develop remedies to purify those waters currently
polluted to the Department, in the form of adopting rules and
regulations as necessary to accomplish these tasks.
The Department's ''Permitting Strategy for High Total
Dissolved Solids (TDS) Wastewater Discharges'' (April 11, 2009)
outlines the foundation and scientific rationale for promulgation of
such rules and regulations necessary to address the existing and
potential pollution of this Commonwealth's waters from large sources
of TDS, sulfates and chlorides. This approach relies upon the basic
water quality management premise that discharges of these pollutants
must be managed through permit limitations required by the more
stringent of treatment-based or water quality-based standards.
The goal of this permitting strategy is that by
January 1, 2011, new sources of High-TDS wastewaters will be
prohibited from this Commonwealth's waters. To achieve this goal,
the Department proposes to amend Chapter 95 to establish new
effluent standards.
In addition to moving this regulatory package
forward, the Department is considering, on a parallel track, the
formation of a work group in the Monongahela River Watershed to
review possible alternative approaches that would also be protective
of this Commonwealth's water resources.
The proposed rulemaking was presented to the Water
Resources Advisory Committee (WRAC) at a special meeting on June 19,
2009, and considered at the WRAC's regular meeting on July 15, 2009.
The WRAC, by majority vote, recommended that the Department work in
conjunction with the WRAC to form a Statewide stakeholders group to
analyze the issues and develop appropriate solutions, in lieu of
proceeding with the currently proposed rulemaking.
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