NCG240000_DWQ Response to Comments_20110921

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DWQ Response to Comments on draft NCG24
September 21, 2011
North Carolina Division of Water Quality Response to Comments
Draft NPDES General Permit NCG240000 for Compost Facilities
September 21, 2011
Backaround
According to the Division of Waste Management, approximately 180 composting facilities were
regulated in North Carolina in 2009. Of those facilities, the surface and groundwater discharges of
approximately 60 may eventually be regulated by permit from the North Carolina Division of Water
Quality (DWQ). DWQ's estimate is that discharges from approximately 30 of that number may be
covered under the General Permit for Compost Facilities (NCG240000, or NCG24). Any surface
water discharges from the remainder of the compost facilities will be authorized via individual
permits or the No Exposure Exclusion from Permitting.
Session Law 2009-322 directed the North Carolina Division of Water Quality (DWQ) to develop a
water quality permitting program specifically tailored to the compost manufacturing industry. Part
of DWQ's development process was to convene the Compost Operation Stakeholder Advisory Group
(COSAG) to obtain industry input. The COSAG engaged in a 9-month public input process,
resulting in several specific recommendations from the COSAG to DWQ as to the form and
substance of the new water quality permitting program. One of the COSAG consensus
recommendations to DWQ was to establish a General Permit covering both stormwater and
wastewater discharges. In response to the Session Law and the subsequent COSAG
recommendation, DWQ developed the draft General Permit for Compost Facilities.
After the COSAG public input process, DWQ sought additional public comment, and the draft
NCG24 was announced in February 2011 via the means required by NC rule, and additional means.
The end of the public comment period was first extended from March 18 to April 18, and extended
again to May 18, 2011; both extensions were in response to requests for more review time from
the regulated community.
DWQ's NPDES General Permits are limited by rule to no more than a five-year term. 2011 will be
the first issuance of NCG24, and it will be reissued in 2016. Every five years DWQ reviews
collected analytical data from the previous five-year term; evaluates identified compliance
problems; reviews problems in permit enforcement; and seeks to improve the effectiveness of the
permits as water quality management tools for the permittees.
EPA Region IV staff in Atlanta reviewed and approved draft NCG24 on January 3, 2011, with the
provision that their additional review and approval would be necessary if the proposed final form of
NCG24 incorporated significant changes from the draft or if significant public comments objecting
to the permit were received. DWQ concludes that neither of these conditions has been established,
and that further EPA review is not required.
DWQ has prepared this summary document both for those interested parties that have submitted
written comments on the draft NCG24, as well as for other interested parties. We will post this
document on the DWQ Stormwater Permitting Unit website for public access.

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DWQ Response to Comments on draft NCG24
September 21, 2011
Comments and Responses
DWQ received written comments from fourteen parties during and after the public comment
periods: six local government composters, one private sector composter, four industry interest
groups spanning both private and public sector membership, one representative of a local
government stormwater utility, and two North Carolina Department of Environment and Natural
Resources (NCDENR) staff outside of DWQ's Stormwater Permitting Unit, and not directly
responsible for the development of NCG24.
In general the comments addressed the costs involved in complying with requirements to control
pollutants in site discharges, and the potential for implementation difficulties, either for DWQ, or
for the regulated community. DWQ appreciates the time and effort reflected in the comments.
The comments have been grouped below by topics. Every written comment pertaining to the new
General Permit for Compost Facilities has been incorporated in the related topics below. We have
noted which comments have been adopted in some form in the final version of NCG24. We have
also identified those comments that we did not incorporate, and why.
1. Recommendations for changes to the draft NCG24 in order to reduce the
permittees' costs associated with compliance with the permit conditions. AND,
2. Comments recommending that a schedule of compliance for existing facilities
should be added to the final form of NCG24.
The costs involved in compliance with water quality permitting for compost facilities was the
single most urgent concern identified in nine months of face-to-face meetings with the
regulated community in the COSAG, as well as in the public comments in response to draft
NCG24. DWQ has revised draft NCG24 in two significant ways to address the concern for
costs and to lessen the immediate impact on the regulated community: NCG24 as revised
provides for an extended compliance schedule for existing facilities (but not for new
facilities); and we have selected a less conservative design storm. We have grouped the
issue of costs and the issue of the compliance schedule together immediately below. Our
response on the topic of setting a design storm as a cost reducing provision is addressed
under item 3 below.
Comments on the costs of controlling polluted discharges from composting facilities were
presented from several perspectives as follows:
a. Some composters may shift to mulching -only operations in order to avoid
the costs attendant with controlling polluted discharges from their facilities
under NCG24; Is this the result intended by the legislature? Should this
point be reviewed by stakeholders prior to enactment of NCG24?
Response: The COSAG also considered comments on the possibility of some degree
of re -alignment within the industry in general as a result of previously existing, but
newly enforced water quality regulations. DWQ's interpretation is that the group
recognized that DWQ was under the mandate of Session Law to roll out a water
quality permitting program for the industry, and while this comment was received by
the group, it did not produce significant discussion in the COSAG.
Result: No change to draft NCG24 requested; none incorporated.
b. Three municipalities provided comments on the timing of their budgeting
calendar, and noted that immediate compliance with draft NCG24 would not
be possible.

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DWQ Response to Comments on draft NCG24
September 21, 2011
Response: Draft NCG24 has been revised to allow existing facilities to set a
compliance calendar in conjunction with the local DWQ Regional Office Surface Water
Protection Supervisor. While the permit still requires expeditious pursuit of the
control of polluted discharges, the revised NCG24 provides a way to lessen the
immediate impact on the regulated community by spreading the costs out over time,
and by allowing the regulated facility time to adequately characterize the polluted
flows so that cost-efficient treatment designs may be implemented.
Result: Draft NCG24 revised to incorporate a compliance schedule in order to delay
and reduce costs for existing facilities.
c. Recommendation that draft NCG24 be revised to incorporate a 2-year
implementation period. Similar recommendation from another municipal
composter for a 3-year implementation period. Another municipal
commenter suggested 4 years for his facility to come into compliance.
Response: DWQ concurs that in most circumstances it will not be possible for
existing facilities to attain compliance with the stormwater benchmarks and process
wastewater limits immediately. Draft NCG24 has been revised to allow existing
facilities to set compliance calendars in conjunction with the DWQ Regional Office
Surface Water Protection Supervisor. While providing flexibility in scheduling, in no
case shall the attainment of compliance with the benchmarks and limits exceed four
years. The draft permit has not been revised to allow the same delay in compliance
for new facilities. New facilities should be compliant upon DWQ's issuance of the
COC under NCG24.
Result: Draft NCG24 revised to incorporate a compliance schedule in order to delay
and reduce costs for existing facilities.
d. In a series of comments, one municipality provided recommendations on
the need for a reasonable compliance schedule. The several aspects of their
comments included: citation and analysis of federal and North Carolina rules
requirements as they may pertain to the draft permit requirement for an
Authorization to Construct permit (ATC) for his existing facility; and the
need for any compliance schedule to be contained within the permit text
itself (rather than outside of the permit text as originally contemplated by
DWQ) as a defense while the facility comes into compliance.
Response: The issue of the proper timing of an ATC for this commenter, and all
existing facilities, is made moot by the July 1, 2011, Session Law revisions to GS
143-215.1. Per that legislation enacted after the draft permit comment period had
ended, DWQ may not require an ATC permit of industrial facilities already covered
under a water quality discharge permit. (See item 7i below for the provisions of the
Session Law.) Draft NCG24 has been revised to eliminate the requirement for
existing facilities.
On the second point, this series of comments was the key exchange with the
regulated community that prompted and informed the changes made to draft NCG24
with respect to a compliance schedule. Draft NCG24 has been revised to allow
existing facilities additional time for compliance.
Result: Draft NCG24 revised to incorporate a compliance schedule in order to delay
and reduce costs for existing facilities.

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DWQ Response to Comments on draft NCG24
September 21, 2011
3. Recommendations that draft NCG24 be revised to set a design storm and to allow
for treatment unit bypasses in large rain events.
This topic represents a series of detailed comments, most from a single municipal
composter. The comments generally noted that the draft NCG24 prohibits
bypasses, and does not identify a design storm for stormwater and process
wastewater design. The two concepts of allowable bypasses and a design basis
storm must work together in order for there to be a rational engineering design of
treatment facilities, otherwise costs can be disproportionate to benefits as larger
and larger facilities are designed. Commenter suggests identifying the 10-year,
24-hour storm as the design storm for stormwater BMPs; and the 25-yr, 24-hr
storm as the design storm for wastewater treatment units. He further suggests
that bypasses occasioned by rainfall in excess of the design storms should be
considered unavoidable bypasses as described in the permit boilerplate. Another
commenter suggests that the hydraulic design of treatment facilities should be
accomplished by a Professional Engineer.
Response: DWQ concurs that revisions to the draft permit on these related points are
necessary, and would be helpful in controlling the size, and ultimately the costs, of
treatment facilities.
For wastewater bypasses: We note that while the text in the permit boilerplate is presented
in terms of prohibiting bypasses, in fact the broad conditions found in the same paragraph
that allow bypasses represent standard, reasonable, good engineering practice and facility
operation. The bypass provisions in the boilerplate of the permit seem appropriate for the
circumstances that would pertain to wastewater bypasses at a compost site.
However, we note and agree with the commenter that a bypass feature designed for the
appropriate storm event would preserve the physical and functional integrity of the process
wastewater treatment system under extreme hydraulic loading, and so would be
categorized as an unavoidable bypass based on the description in the permit text, as
suggested by the commenter.
Design storm selection for process wastewater treatment systems: DWQ agrees that the
permit text should address the selection of a design storm. Further, considering that
compost sites generally are expansive in extent and can generate large volumes of water, it
is our judgment that the design storms suggested by the commenter (10-yr for
stormwater, and 25-yr for wastewater) would lead to very large treatment units, and
very large costs. DWQ notes that the there is some limited DWQ precedent for setting a
design storm for bypasses of wastewater treatment facilities in special permitting and
compliance circumstances. For NCG24, DWQ has established that process wastewater
system bypass discharges in response to rainfalls greater than the 2-yr, 24-hour rainfall
meet the qualifications for an unavoidable bypass, and so are permissible under the
permit conditions in NCG24, provided that the bypass meets the other related conditions in
the permit boilerplate as well. For discharges driven by rainfall events, control and
treatment of the 2-yr, 24-hr storm should address well in excess of 90% of the total
annual pollutant discharges.
For stormwater bypasses: We take a different view of the need to set a design storm for
stormwater BMPs. We note that a stormwater benchmark exceedance is not a permit
violation, but a call for management awareness and response. In the case of a benchmark
exceedance the structure of the permit contemplates a stepped approach that evaluates the
feasibility of measures to achieve benchmark compliance. We think this is an adequate
approach, and we believe that the design engineering community and the regulated

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DWQ Response to Comments on draft NCG24
September 21, 2011
permittees can size stormwater BMPs on the basis of their own analysis of risk and
compliance.
With respect to wastewater treatment facilities, NC rule already requires that wastewater
treatment facilities be designed by a Professional Engineer; we do not think it is necessary
to repeat that rule requirement in the permit text. However, it will be inserted in the
application form for NCG24.
Result: In order to reduce initial construction costs, DWQ has revised the draft NCG24 to
add the requirement of a 2-yr, 24-hr design basis minimum for any bypass to qualify as an
unavoidable bypass of a process wastewater treatment system. Draft NCG24 has been
revised to require recording in the SPPP of every bypass from process wastewater treatment
units. DWQ will continue to implement the existing NC rule requirement for process
wastewater treatment facility design (including hydraulic design) by a Professional Engineer.
4. Questions or recommendations as to changes to draft NCG24 in order to change
the scope of industrial activities regulated by the permit and/or DWQ's permitting
program.
a. Comment stating that mulching operations are not regulated by NCG24.
Response: (Note: it was DWQ's suggestion in the original discussions of HB1100,
subsequently SL 2009-322, that the scope of the bill be revised to exclude mulching
operations since they are fundamentally different from a process perspective.)
DWQ's authority to regulate is limited to industrial activities, at the captured
industrial site, which in the case of NCG24 includes all the on -site steps involved in
compost manufacture at the compost facility. What that means is that discharges
from mulching at a stand-alone mulching -only operation (not a composting facility)
are not regulated by NCG24. Discharges from mulching taking place at a compost
facility to provide shredded or chopped feedstock materials to the on -site composting
operation are regulated by NCG24. DWQ considers that stand-alone mulching
operations lack the qualifying characteristic of significant accelerated biological
decomposition that characterizes composting operations.
Result: No change requested to draft NCG24; none incorporated.
b. Comment that Type 1 yard waste facilities should be exempt from the
stormwater permitting process. Another related comment was that one
facility operator is not aware of any water quality problems due to
discharges from his Type 1 facility, Additionally: DWQ received two verbal
inquiries, but no written comments as to how new legislation in SL 2011-
394 would impact draft NCG24 and the composting water quality permitting
program authorized by SL 2009-322. The 2011 law provides that DWQ shall
not require water quality permitting for Type 1 facilities, "unless required to
do so by federal law."
Response: Federal rule requires that stormwater permits be issued to industrial
activity described in 40CFR122.26(b)(14), which includes compost manufacture, and
does not exclude Type 1 compost facilities. Further note that Session Law 2009-322
requires DWQ to tailor a permitting program especially for the composting industry,
and does not specifically exclude Type 1 facilities from regulation. DWQ notes the
qualifying phrase in the Session Law, and believes that it operates to allow the
conclusion that DWQ may require water quality permitting of Type 1 facilities on the
basis of federal rule requirement, while still complying with SL 2011-394.

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DWQ Response to Comments on draft NCG24
September 21, 2011
Regarding the report that a particular facility has operated for many years without
the operator being aware of any water quality problems, no additional information
was supplied to indicate what level of vigilance in water quality monitoring and
testing was employed to support the report, and the presumably implied conclusion
that there have been no polluted discharges.
During the nine -month public COSAG discussion, there was no evidence presented in
support of any assertion that the discharges from Type 1 facilities did not contain the
pollutants suggested by the data presented to the COSAG in DWQ Report #3, and
reproduced in the Fact Sheet.
Result: No change in the draft permit text.
c. Comment stating the understanding that a compost facility located on an
MSW landfill would not be regulated by NCG24.
Response: Case -by -case circumstances would dictate whether additional coverage
under NCG24 would be appropriate. MSW operations are currently the location of
many varying activities that do not fit the narrowest description of landfilling,
including composting. As a beginning point for case -by -case considerations, we
currently imagine that the stormwater discharges from a small-scale composting
operation at a large MSW facility would not warrant an extra permit (NCG24) in
addition to the presumably already existing stormwater General Permit for Landfills.
On the other hand, the Landfill General Permit only authorizes the discharge of
stormwaters, and does not authorize the discharge of wastewaters, and any
process wastewater generated from a small scale composting operation would have
to be handled on site, i.e. could not be discharged. There may be many variations of
site conditions that could give rise to different regulatory scenarios. We intend to
address the case -by -case circumstances as they arise.
Result: No change to draft NCG24 requested; none incorporated.
d. Recommendation that storm debris sites should not be regulated by NCG24.
Response: Stand-alone storm debris -only sites are not regulated by NCG24.
However, if storm debris piles are on the site of a compost manufacturing activity,
for the purpose of providing feedstocks to the composting process, the debris staging
area would be considered part of the compost manufacturing activity and discharges
from the storm debris would be subject to the site -wide permit applicable to the
other on -site operations, NCG24.
Result: No change to draft NCG24 requested; none incorporated.
e. Recommendation that Large Type 3 and Type 4 compost operations should
be allowed coverage under NCG24, contrary to the scope limitations
currently in the draft permit.
Response: DWQ is concerned that larger facilities with more varied feedstocks and
with manures and sludges deserve a closer regulatory review than what we hope will
be an expedited review under NCG24. Also note that the determination to initially
exclude Large Type 3 and Type 4 facilities from NCG24 was the consensus
recommendation from the COSAG to DWQ. It may be that once we have more
experience with permitting the industry, we can expand the scope of NCG24 to allow

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DWQ Response to Comments on draft NCG24
September 21, 2011
us to issue it to Large Type 3 and Type 4 facilities. We view the draft permit
exclusion as precautionary, and as parallel to the DWM classification system which
recognizes an increased risk with increasing compost facility Type category. Note
that the face page of NCG24 does allow that it may be used, at DWQ discretion,
upon our finding that a Type 3 or Type 4 facility is sufficiently similar to the lower
category facilities which are covered by NCG24.
Result: No change in the draft permit text; note that some flexibility on this point is
already built into the permit.
f. Recommendation that draft NCG24 be revised to exempt vehicle
maintenance area monitoring requirements if all maintenance is done under
roof.
Response: The provisions for stormwater monitoring of vehicle maintenance runoff in
draft NCG24 are identical to most other stormwater permits issued by DWQ since the
mid-1990's. There is EPA guidance, and well established precedent within the DWQ
NPDES stormwater permitting program, that being under roof does not exempt a
facility from the vehicle maintenance area monitoring.
The posture of the NPDES stormwater program is to address activities on an
industrial site beginning with whether an activity or material is present, not
necessarily how likely a polluted discharge may be. Industrial activities are
frequently fluid with respect to staff awareness and site management attention to
stormwater pollution, manufacturing processes, and physical configuration of
manufacturing steps. We note that draft NCG24 carries the standard threshold
above which monitoring activities are required in other stormwater permits. Where
there is greater than the threshold amount of 55 gallons of motor oil per month,
DWQ believes the increased risk of pollutant discharge from those vehicle
maintenance activities deserves the extra attention involved in monitoring the
discharges.
Result: No change in the draft permit text.
5. Recommendations and questions related to the monitoring and other recurring
requirements of draft NCG24.
a. Request that the quarterly monitoring results obtained under NCG24 be
compiled annually by DWQ, interpreted, and made available to the public.
Response: DWQ has already accepted this assignment from the COSAG, and several
industry participants in the COSAG have volunteered to assist in review and
interpretation.
b. Request to eliminate heavy metals testing from Type 1 facilities based on
information in the Fact Sheet.
Response: We feel this comment may misinterpret the limited data as evidence of
the absence of heavy metals in compost discharges from Type 1 facilities. In the
COSAG meetings industry representatives offered anecdotal comments that heavy
metals are concentrated in woody feedstocks. Data contained in the Fact Sheet
represented mixed feedstock facilities in other states showed heavy metals content.
While those facilities did not have only Type 1 feedstocks, they did include as part of

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DWQ Response to Comments on draft NCG24
September 21, 2011
the feedstock materials the feedstocks that would be present in Type 1 facilities.
Once the required analytical testing results from NCG24 begin to accumulate, DWQ
and the COSAG volunteers can review that data against this question.
Result: No change in draft permit text.
c. Why are analytical and visual inspections both required quarterly instead of
semi-annually like other permits? This extra testing increases the cost of
compliance.
Response: It is correct to note that where NCG24 requires quarterly monitoring,
most other stormwater permits require only semi-annual monitoring. However,
DWQ considers that composting operations have the potential for much greater
exposure of process materials than most other manufacturing activities largely under
roof: significantly more of the process is outdoors in composting operations. More
significantly, compost operations have the potential for much greater variability in
site configuration over time. These two aspects of a typical compost site work
together in our eyes to suggest that the greater frequency of monitoring is a prudent
tool in the site manager's execution of his responsibility to control the discharge of
pollutants from his site.
Result: No change in the draft permit text.
d. Recommend eliminating requirement for continuous flow measurement on
process wastewater discharges in footnote to Table 7 as these flows may be
intermittent. Recommend allowing for estimates of total flow. Related
comment: Recommend eliminating total flow measurement for process
wastewater discharges based on the observation that some facilities have
been designed for overland flow.
Response: The footnote has been revised to include general language intended to
broaden the acceptable bases for calculating total flow. Estimating the total flow
based on an assumed runoff coefficient for the contributing area is not an acceptable
basis for calculating total flow. Where facilities have overland flow treatment
systems or discharges, DWQ will consider case -by -case exceptions to the total flow,
but absent a specific example to serve as a model, we will not revise the permit text
to address what we believe is an infrequent site condition.
Result: Footnote 3 to Table 7 revised to allow for greater flexibility in total flow
measurement.
e. Recommendation that DWQ initiate a 5-year study period so that reasonable
process wastewater discharge limitations may be set. Additional similar
verbal comment received in the DWQ/DWM workshop for composters held
April 28, 2011 in Winston-Salem.
Response: A 5-year study for further pollutant characterization of the process
wastewater discharges would not change the federal rule establishing the limits. The
discharge limits in draft NCG24 are found in federal rule at 40CFR133.102 which
identifies the minimum level of effluent quality attainable by secondary treatment.
These are the numerical values to be attained after treatment. Further sampling and
study for characterization of the untreated discharges is not directly relevant to the
setting of discharge limits for treated discharges.

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DWQ Response to Comments on draft NCG24
September 21, 2011
Result: No specific change requested in the draft permit text; none incorporated.
The recommendation is not persuasive as a basis to delay the roll -out of DWQ's
permitting program for compost facility discharges.
f. Recommendation for more testing to establish reasonable stormwater
discharge benchmarks instead of from the highly variable data from a single
in -state yard waste facility. Review of the data in the Fact Sheet suggests
that many if not all facilities might fail to meet benchmarks, setting up an
untenable, unreasonable regulatory result. More discussion is needed to
establish reasonable benchmarks.
Response: All industries in North Carolina with stormwater discharges have identical
stormwater benchmarks wherever a particular parameter is of concern. (Some
benchmarks may vary depending on the class of the receiving waters, but not on the
industry category.) The numerical values of benchmarks are set at a level to protect
the receiving waters, and are not set based on what level of pollutants might be in
any one industry's stormwater discharges. Compost benchmarks are the same as
other industries'.
The benchmarks were not set based on data from the in -state yard waste facility.
The data presented in the Fact Sheet is descriptive of untreated stormwater
discharges. In contrast, the stormwater benchmarks are goals set for the treated
discharges, and are applied state wide to all industrial dischargers, whether
composters or not.
Concerning many facilities not meeting benchmarks and the untenable regulatory
result, we agree that if a facility chooses to discharge untreated stormwater it is
likely that they will not meet benchmarks, and the consequential provisions of the
permit would apply. However, the comparison of the pollutant content of untreated
flows with the treated discharge benchmark values is not meaningful because it
presumes that the facility will not treat the stormwater. The treatment of
stormwater to reduce the pollutants discharged is the specific objective of the
permitting program.
Result: No specific change requested in the draft permit text; none incorporated.
The comments are not persuasive as a basis to delay the roll -out of DWQ's
permitting program for compost facility discharges.
g. Recommendation to amend draft NCG24 to allow a tiered response to
wastewater violations so that facilities can address problems in a timely
fashion. The comment cites the following supporting considerations:
effluent limitations were based on a highly variable and very limited data
set; every facility cited in the fact sheet would exceed the limitations
resulting in an untenable and unreasonable regulatory result; stormwater
benchmarks are more lenient than wastewater limits and should be adopted
for wastewater.
Response: As noted above, the process wastewater limits were not based on the
site -specific data reported in the Fact Sheet, but are based on federal rule values.
DWQ feels it is erroneous to conclude that every facility will violate process
wastewater limits unless we assume that every facility will fail to install sufficient
treatment facilities. As to setting the process wastewater limits equal to the more

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DWQ Response to Comments on draft NCG24
September 21, 2011
lenient stormwater benchmarks, the benchmarks and limits contained in draft NCG24
were discussed in the COSAG, and formed the basis of the COSAG's recommendation
back to DWQ. Extended discussion over the rules -based distinction between
wastewater and stormwater took place in the COSAG, including the difference in
limits vs. benchmarks. DWQ feels compelled to assign significant weight to the
negotiated and consensus results from the COSAG process in preference to contrary
comments.
However, DWQ appreciates that some extended time may be necessary for facilities
to design, install, and bring into compliance wastewater treatment facilities capable
of reliably meeting the process wastewater limits. Based on this consideration we
have included the compliance schedule provisions discussed in response to comment
topics 1 and 2 above.
Result: Draft NCG24 has been revised to incorporate provisions to allow an extended
time frame for full compliance with the process wastewater effluent limitations.
NCG24 will not be revised to incorporate tiered response provisions for wastewater
discharges.
h. Recommendation that draft NCG24 be revised to make the stormwater
benchmarks less stringent, and comparable to the benchmarks and
monitoring frequency in the General Permit for stormwater discharges from
landfills.
Response: The parameters recommended by the COSAG for DWQ's permit
monitoring requirements were chosen based on the assessment of risk from the
industry's discharges. All the parameters included appear in the literature as actual
pollutants discharged from compost sites in other states. For the three shared
analytical parameters common to both the landfill permit and NCG24 (TSS, COD, and
fecal coliform), the benchmark values for the two permits are identical; draft NCG24
is not more stringent for those pollutants, contrary to the comment. The numerical
values for wastewater limits are found in federal rule as noted above.
Result: No change in the draft permit text.
6. Recommendations and questions related to the definitions of stormwater and
wastewater in draft NCG24. These comments encompassed several perspectives,
but most sought to revise the draft permit definitions of wastewater and
stormwater, or their applicability to Type 1 facilities:
a. Two similar comments may be taken together. There is no rules basis for
considering yard waste runoff stormwater. There is no EPA definition
establishing that yard waste runoff is process wastewater.
Response: The basis for regulating flows from composting facilities was discussed at
length in the public COSAG meetings, and was presented in written form to the
COSAG in DWQ Report #1 which is posted on the COSAG website hosted by DWM.
The COSAG agreed by consensus to recommend to DWQ the definitions of
wastewater and stormwater reflected in draft NCG24.
Additionally, DWQ's rationale for regulating stormwaters and wastewaters was
presented at the time of the initial publication of draft NCG24 in the Fact Sheet. We

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DWQ Response to Comments on draft NCG24
September 21, 2011
note that these comments object to regulation of stormwater and wastewater
discharges, but do not advance any rules -based argument in support of the
objection, and contradict the clear requirements in federal rule. In short,
stormwater flows are regulated by federal rule by inclusion of discharges from SIC
28 facilities (compost manufacture is included in SIC 28 via category SIC 2875) as
part of the definition of regulated stormwaters; process wastewater discharges are
regulated by federal rule via the definition of process wastewater' at 40CFR122.2.
Result: No change in draft permit text.
b. Runoff from yard waste is not considered a wastewater when it is at the
curbside, so it seems inconsistent and without basis to consider it
wastewater at a compost facility.
Response: DWQ's regulatory authority in federal rule is attached to discharges from
industrial facilities. The manufacture of compost is considered an industrial activity.
In this case, DWQ's permitting authority follows federal rule in that we are limited to
permitting flows from the site of manufacturing activities. DWQ has no permitting
authority to regulate discharges from curbside deposits of yard waste. This principle
of the NPDES program was explained verbally to the COSAG membership, including
the several representatives primarily concerned about yard waste facilities
(representatives from Solid Waste Association of North America (SWANA), North
Carolina League of Municipalities (NCLM), and North Carolina Association of County
Commissioners (NCACC)), and presented to the COSAG in written form in DWQ
Report # 1.
Result: No change in draft permit text.
c. Recommend that Type 1 and Type 2 should be subject only to stormwater
discharge regulations and not subject to NCG24.
Response: This recommendation is contrary to the recommendation received via the
public stakeholder process in the COSAG. DWQ feels compelled to assign
preferential weight to the considered and negotiated recommendations from that
group. We note the objection; however, there is no rules -based argument here that
might persuade DWQ to a different interpretation of the federal rules. Compost
facilities are captured by federal rule, and no exemption for them is provided in
federal rule.
Result: No change in draft permit text.
d. How will DWQ know when a final product qualifies as finished compost?
And consequently whether a discharge from final product is regulated as
stormwater or wastewater? Can DWQ provide guidance on this point?
Response: DWQ will rely on DWM to inform us as to the character of the final
product authorized under the DWM composting permit for each facility. This topic
was discussed in the COSAG process and formed the basis of a recommendation

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DWQ Response to Comments on draft NCG24
September 21, 2011
from the COSAG to DWQ. The final product may meet the newly defined category,
'finished compost', or it may not, depending on the permitted (DWM permit) degree
of completion of the biological degradation attained in the final product. In the first
case, DWQ will presumptively consider the flows to be stormwater. In the second
case, DWQ will consider the flows to be wastewater. This rationale is presented in
the Fact Sheet and addressed as well in Part II Section E of the draft NCG24.
Result: No change to the draft permit text. However, we concur that additional
explanation and communication would be helpful on this new feature of the DWM
composting program and its application in the DWQ permit. We will seek out
additional ways to communicate to the industry on this topic. We do not think that
the additional explanation and communication should take place within the text of
NCG24, where it is already addressed briefly.
e. All discharges from Type 1 facilities should be regulated as stormwater
because facilities can meet stormwater benchmarks much cheaper than
meeting wastewater limits, which may require the construction of
wastewater treatment facilities. The difference in cost makes regulation as
stormwater economically feasible, but makes regulation as wastewater too
costly.
Response: DWQ recognizes that the additional costs generated by compliance with
existing federal rule and DWQ's proposed draft permit requirements may be
substantial. Large existing facilities especially may face considerable costs. We
concur that draft NCG24 should be revised to reduce the financial impact to existing
facilities. Consequently, we have revised draft NCG24 to include an extended time
period in which existing facilities may approach full compliance in a stepped manner,
thereby spreading out costs over time.
At the recommendation of the COSAG, DWQ has revised draft NCG24 to allow
existing facilities extra time for compliance, but to require new facilities to attain full
compliance upon issuance of the Certificate of Coverage under the permit. See the
related responses to comments in items 1 and 2 above.
In response to concerns about costs, DWQ has amended the bypass provisions to
consider that bypasses resulting from the 2-yr, 24-hr rainfall event are permissible
as 'unavoidable bypasses.' We are aware of recent preliminary designs for public
sector and private sector composters that used, in part, the 25-yr, 24-hr rainfall
event for preliminary estimates of construction costs, a significantly more costly
engineering approach. One Type 1 yard waste, public sector composter commented
that facilities should be designed for the 10-yr storm for stormwater BMPs and the
25-yr storm for process wastewater treatment facilities. DWQ's revisions to draft
NCG24 should significantly reduce the ultimate costs, and should spread out those
costs over time.

Page 13 of 18
DWQ Response to Comments on draft NCG24
September 21, 2011
While NCG24 treats new facilities differently than existing facilities, no persuasive
argument has been advanced that legitimizes a difference in regulatory treatment
between Type 1 facilities and other types of composting facilities.
Result: Draft NCG24 has been revised to allow existing facilities (whether Type 1 or
other) an extended period of time to spread out the costs in order to come into full
compliance with permit requirements. However, we do not think the redefinition of
wastewater and stormwater contrary to federal rule should be the basis of
addressing this very significant issue. There is no change to draft NCG24 as to the
definition and application of the distinction between wastewater and stormwater
discharges.
f. Recommend that the draft NCG24 definition of 'finished compost' be revised
to make no distinction as to degree of completion of the final product.
(DWQ also received a contrary comment from DWM recommending that the
draft NCG24 permit definition be retained, as per the original COSAG
recommendation to DWQ.)
Response: The rationale behind the COSAG approval of the new terminology
'finished compost' was the shared recognition that final product might meet the DWM
requirements of PSRP and PFRP and yet still be significantly different in character
and different in pollution potential from the most completely degraded compost
products, with respect to potentially high concentrations of pollutants other than
bacteriological pollutants. The comment provides no additional information that
would persuade DWQ to abandon the recommendation from the COSAG.
Result: No change in the draft permit text.
7. Miscellaneous and narrow scope comments; pertaining to specific text provisions
of draft NCG24, or the DWQ implementation of our water quality permitting
program for composters, and other comments.
a. Part I Section A, fifth paragraph. Comment suggests that this paragraph
could be revised to clarify when an existing facility should apply for an
individual permit.
Response: NCG24 is intended to focus on those facilities to which it pertains. This
paragraph in the permit text while accurate is informational, and not intended to
define the remainder of our program implementation. All existing permittees were
sent a letter jointly authored by DWM and DWQ in the first quarter of 2011 indicating
the upcoming deadline of July 2012 for application submittal to DWQ, whether for
the General Permit NCG24, or whether for an individual permit. A follow-up letter
will be sent in January 2012 to all existing facilities reminding them again of the
same deadline. Other than this reference on the availability of individual permit
coverage, we prefer to keep the elements of the implementation of the individual
permits outside of the General Permit text.
Result: No change in the draft permit text.

Page 14 of 18
DWQ Response to Comments on draft NCG24
September 21, 2011
b. Comment suggests that DWQ develop technical guidance on BMPs and
provide that to the permittee along with the initial transmittal of his
Certificate of Coverage.
Response: At the request of the COSAG, DWQ has already begun development of a
brief BMP Manual for composters. The single page per BMP format is intended to
generally inform interested parties, but it cannot be a complete design manual. We
will post the BMP Manual on the SPU website when it is completed, in November
2011. Due to budget constraints we must make the electronic version publicly
available rather than printing color copies of the document.
Result: DWQ concurs that the BMP Manual may be helpful, and we will make it
available on the Stormwater Permitting Unit website. We will not include a copy of it
in each COC to our permittees.
c. Part I Section A, second and third paragraphs. Comment requesting
clarification and suggesting that the distinction drawn between wastewater
and stormwater is not as presented verbally in a DWQ/DWM informational
workshop held in Winston-Salem on April 28, 2011.
Response: The two referenced paragraphs of the permit text supersede any verbal
interpretation made in the workshop, and we judge that the two paragraphs taken
together are clear. We apologize for the unintentional miscommunication in the
workshop.
Result: No additional clarification will be provided in the permit text.
d. Part II Section A1(e). Why must stormwater outfalls be inspected annually
rather than just once like other permits for the presence of non-stormwater
discharges? What constitutes recertifying?
Response: This provision for annual recertification is included in every NPDES
industrial stormwater permit (approx. 2000 permits in North Carolina) containing the
requirement for an SPPP. It is intended to insure that the site manager checks at
least once each year to be certain that no other flows are getting into stormwater
outfalls. The recertification does not require more than the site manager or his/her
staff examining the outfalls on a dry day to ascertain that there are no other
discharges in the stormwater outfalls, and that he signs a recertification statement to
that effect.
Result: No change requested; no change in the draft permit text.
e, Part II Section A4. Question as to why the Preventative Maintenance and
Good Housekeeping Program is more detailed and more extensive than in
other stormwater permits.
Response: Every NPDES industrial stormwater permit requiring an SPPP also
contains this section in one form or another. DWQ typically makes minor changes to
the content in this portion in order to more directly tailor the general permit
requirements to the specific industry it applies to, and to the stormwater pollutant
risks identified for that industry sector. The question did not specifically identify a
particular provision as being inappropriate, and upon further review of the section
the provisions in it seem reasonable management actions for the control of pollutant
risk from composting operations.

Page 15 of 18
DWQ Response to Comments on draft NCG24
September 21, 2011
Result: No specific change requested; no change in the draft permit text.
f. Part II Section A7. Suggestion that instead of the annual update to the
SPPP, the draft permit text should be revised to require an update in the
event of a significant change in design, operations, construction or
maintenance. Comment notes that additional work and expense is involved
with annual updates.
Response: The draft permit text already requires that the SPPP be updated in the
event of a change that may impact the potential for stormwater pollution. The text
also requires that management update the SPPP at least annually. These are the
same provisions contained in all other North Carolina NPDES industrial stormwater
permits requiring an SPPP.
The SPPP is intended to be a working tool for the on -site manager in the control of
pollutants in his stormwater discharges. While some costs might arise from portions
of the SPPP update being accomplished by consultants charging a fee, the primary
purpose of the SPPP update is to have on -site management actively_ participating and
actively aware of changing on -site conditions and how they might impact stormwater
pollution. This is a task that must be primarily accomplished by the on -site
manager, not by a paid consultant.
Compost sites have the potential to be much more fluid in configuration than many
other manufacturing activities. Different process configuration and different uses for
any one area of a site could give rise to different pollutant risks in the discharges
from the area. DWQ expects the site manager to be alert to those changes and how
they might potentially impact the risk of stormwater pollution. An annual review
seems consistent with the site manager's responsibility for controlling polluted
discharges from his site.
Result: No change in the draft permit text addressing SPPP updates; the permit will
continue to require both an annual update as well as revisions when significant
changes occur.
g. Several commenters requested copies of the two studies that DWQ reviewed
in considering the characterization of discharges from compost facilities.
Response: Data from the two studies were presented in the COSAG meetings as
DWQ Report #3, and it is posted on the COSAG website hosted by DWM. The studies
were also cited in the Fact Sheet, published concurrently with draft NCG24. Full
attributions as to the source of the data were provided, and the reports are available
via internet search. Due to budget constraints, DWQ is not able to provide paper
copies of large documents.
Result: The two studies may be searched for by the followina titles:
• Evaluation of Compost Facility Run off for Beneficial Reuse - Phase I and
Phase II, Clean Washington Center, January 2000.
• Commercial Composting Water Quality Permit Development, prepared for
Oregon DEQ Land Quality and Water Quality Divisions, by CH2M Hill, May 12,
2004.

Page 16 of 18
DWQ Response to Comments on draft NCG24
September 21, 2011
h. DWQ received one set of comments related to the pollutant characteristics
of runoff from woodland areas in comparison to runoff from municipal yard
waste compost manufacturing facilities (Type 1 facilities). Have any studies
been done on woodland runoff? Have any studies been done on yard waste
facility runoff? How do they compare? The results might be very
informative.
Response: DWQ reads the set of comments all together to mean that discharges
from Type 1 compost facilities may be relatively innocuous when compared to
woodland runoff. In nine months of public COSAG meetings, there were no
occasions when any representatives from the municipal sector (largely Type 1
facilities, with representatives from SWANA, NCLM, and NCACC) provided evidence
supporting innocuous discharges from their facilities. While it may be the case that
Type 1 yard waste facilities may be less polluting than other types of composting,
the limited literature available from out-of-state compost facilities suggests that
mixed facilities including yard waste and other types of composting still have the
potential for highly polluted runoff.
Our review of the limited existing data available from the largest Type 1 facility in
North Carolina suggests that untreated discharges from that facility:
• Had discharges that regularly contained greater than the numerical value of
in -stream water quality standards for fecal coliform, usually by several orders
of magnitude;
• Exceeded total suspended solids wastewater limits on four occasions out of
six data points; and exceeded stormwater benchmarks 50% of the time;
• Exceeded stormwater benchmarks for phosphorus six times out of 10 data
points;
• Exceeded stormwater benchmarks for COD nine times out of 10 data points;
• Exceeded wastewater limits for BOD three times out of 10 data points;
• And were uniformly compliant, untreated, for pH, oil and grease, and the
several nitrogen species commonly employed as pollutant measures.
While we note that permittee monitoring under NCG24 will provide data to better
characterize the industry discharges as the permittees complete their monitoring
obligations, DWQ concludes that there is sufficient evidence now to continue forward
with the permitting and regulation of discharges from Type 1 yard waste facilities.
Result: No specific draft permit revision was suggested; no change in the permit
text.
i. Session Law 2011-394 Section 9(a5), effective July 1, 2011, may also affect
NCG24. A section of the law provides that DWQ may not require an
Authorization to Construct permit for facilities that have already received a
DWQ discharge permit. The relevant part of the law appears to be, in part. -
"No permit shall be required... to construct, install, or alter any treatment works or disposal
system within the State when the system's or work's principle function is to ...treat... or
dispose of industrial waste or sewage from an industrial facility and the discharge of the
industrial waste or sewage is authorized under a permit issued for the discharge of the
industrial waste..."
Response: DWQ will comply with this new provision in the General Statutes in two
ways in NCG24.
• For existing facilities, we will abide by previous legislation (SL 2009-322)
requiring that our permit program be completely phased -in not later than

Page 17 of 18
DWQ Response to Comments on draft NCG24
September 21, 2011
October 2012, by holding to the previously publicized July 2012 deadline for
receipt of permit applications from all existing and future composters subject
to regulation via a water quality discharge permit. We have revised draft
NCG24 to remove the ATC requirements for existing facilities, since we plan
to issue permits to them well before it would be reasonable to expect
meaningful ATC submittals to us. These existing facilities will have coverage
under NCG24, and in compliance with SL 2011-394, we will not require an
ATC permit.
For new facilities, we will preserve the draft permit text that requires plan
submittal, review, and approval prior to issuing coverage under NCG24. This
approach is consistent with the qualifying language present in the text of SL
2011-394. We note that the revisions to GS 143-215.1 make the exemption
from an ATC permit contingent upon the facility already having a discharge
permit, which these new facilities will not have:
"No permit shall be required... when... the discharge is authorized under a permit issued for the
discharge of the industrial waste or sewage".
Note further the overall intent of the Session Law as captured in the partial
title of SL 2011-394,
"AN ACT TO AMEND CERTAIN ENVIRONMENTAL AND NATURAL RESOURCES LAWS TO ... (9)
PROVIDE THAT NO PERMIT IS REQUIRED FOR THE CONSTRUCTION OR ALTERATION OF A
SEWER SYSTEM OR TREATMENT WORKS THAT ALREADY HAS A DISCHARGE PERMIT" [Bold
text added for focus.]
Result: DWQ revised draft NCG24 to eliminate the requirement for an ATC for
existing facilities eligible for NCG24. The requirement of treatment system plan
review and approval for new facilities is retained in concept, and minor wording
revisions have been incorporated in NCG24.
j. Recommendation to add definitions of compost, compost facilities, and the
types of compost facilities to the draft permit text.
Response: The face page of draft NCG24 already references the sections of solid
waste regulations describing all of the requested definitions. We believe the existing
text is sufficient, and that there is some small risk of incompatible definitions should
DWM subsequently change their regulations.
Result: No change in the draft permit text.
k. Several commenters observed that cities have been prohibited from the
landfilling of yard waste by act of the North Carolina Legislature in 1989,
and requested NCDENR to revise that law to allow the landfilling of yard
waste. DWQ received one additional comment disputing the relevance of
the original comment.
Response: DWQ notes that some sectors of the composting industry feel that the
1989 yard waste ban should be repealed.
Result: No change to draft NCG24 requested; none incorporated.

Page 18 of 18
DWQ Response to Comments on draft NCG24
September 21, 2011
8. One private sector composter urged DWQ to expedite the DWQ permitting process
for Large Type 3 and Type 4 composting facilities, noting that past water quality
permitting for compost facilities has been an extremely drawn out process.
Response: DWQ agrees that, for a variety of reasons, past permitting durations have been
unduly protracted for most of the very few existing facilities (5) that have ever applied for a
water quality permit for composting operations. While the development and
implementation of NCG24 will not directly speed permitting for Large Type 3 and Type 4
facilities (since they will be covered by individual permits, not NCG24), NCG24 will serve as
our beginning template for individual permits. Our expectation is that this will speed up the
issuance of individual permits.
Result: No specific change to draft NCG24 proposed and none incorporated. Constructive
comment on DWQ program implementation outside of NCG24 acknowledged.
END