NRDC Secondary Treatment Petition Fatally Flawed
The NRDC, on behalf of
several environmental organizations, has petitioned the EPA to redefine
"secondary treatment" to include removal of nitrogen and phosphorus.
The proposal presumes environmental improvement will result. The proposal
trivializes the impact nutrient removal will have on POTW capital and operating
costs. It also presumes that POTWs are
the dominant source of nutrient loading to receiving waters and ignores the
fact that in many cases non-point sources of nutrients control water
quality. Please read the NRDC proposal
to see how this proposal will affect you and your community. A link to this
information is included at end of this page.
The NRDC proposal
presumes that there will be an environmental benefit in implementing
nutrient removal at all POTWs nationwide. As most POTW directors, design
engineers, discharger groups, environmental attorneys and regulatory agencies
know, this is not always the case. Widespread implementation of nutrient
removal as proposed by the NRDC will require many POTWs to invest in costly
upgrades. Contrary to the proposal premise, environmental benefit is not a
universal result of nutrient reduction. Some POTWs have invested in costly
plant improvements to meet nutrient removal objectives that have resulted
in no environmental benefit in their receiving waters. The NRDC makes a valid point that there
are some waterbodies that will benefit from nutrient removal; however,
this is not sufficient justification to impose advanced treatment on all POTWs.
They also accurately point out that simple re-configuration of
existing POTWs can provide some nutrient reductions. A simple retrofit may
work for some facilities but most POTWs will inevitably have to invest in
upgrades such as nitrate recirculation systems, step feed systems, increased
blower capacity, improvements to secondary clarifiers and chemical feed
systems to achieve the treatment objectives being proposed by the NRDC. Also,
certain treatment processes, such as attached growth systems, do not lend
themselves to simple low-cost upgrades for nutrient removal.
2. Reconfiguring existing POTWs may require re-rating these plants which may result in a reduction in permitted design flow and a devaluation of the facilities. Re-rating could affect Master Plans and limit future development in the area served by the POTWs.
3. For
each POTW, a balance must be achieved between the negative impacts of the
current level of nutrients, the actual cost of phosphorus and nitrogen
reductions, and the proven or realized environmental benefits of the reduction.
The NRDC petition attempts
to dictate POTW upgrades through redefining secondary treatment rather than
through the use of good science and engineering. It will circumvent the TMDL
process that was developed to incorporate good science into identifying POTW
improvements that will result in desired environmental benefits
