(1) The department
may exempt a land treatment system from specific requirements of this chapter
if the owner or operator can demonstrate that the requirement is more stringent
than necessary to comply with the provisions of ch. NR 140 and ch. 160, Stats.
As required in s.
160.19(2),
Stats., this chapter defines design and management practice criteria for land
treatment systems to minimize the level of substances in groundwater to the
extent technically and economically feasible and to comply with the groundwater
preventive action limits established in ch. NR 140. The concepts of matching
the waste loading to the soil conditions, uniform wastewater distribution, a
load/rest cycle and nutrient removal by crop uptake are essential in order to
minimize the groundwater impacts from waste treatment on land. However, there
may be site specific factors that determine how these concepts are best applied
to a specific facility. To justify an exemption from a requirement of this
chapter, the owner or operator shall demonstrate the following:
(a) That site specific factors, such as
pollutant-soil interactions, higher than normal crop nutrient uptake or
pollutant dilution, dispersion or degradation within the design management
zone, justify an exemption from the requirements of this chapter. The influence
of site specific factors shall be demonstrated in an evaluation of the waste
loading, hydrogeologic conditions, soil type and treatment capabilities of the
site to present grounds for an exemption. Soil investigation information such
as that specified in s.
NR 214.20 may be requiredas part of the treatment system
evaluation;
(b) That increases of
substances in the groundwater from land treatment on the site will be minimized
to the extent technically and economically feasible; and
(c) That the applicable groundwater limits
will not be exceeded. The following evidence shall be part of the exemption
request for each of the following groups of land treatment systems:
1. Existing systems with groundwater
monitoring wells. The owner or operator shall demonstrate compliance with the
appropriate groundwater standards in all monitoring wells by presenting
groundwater monitoring data from the land treatment system. The department may
require installation of and data from additional monitoring wells if the
groundwater monitoring well network is believed to not adequately represent the
impacts from land treatment of wastes on the site.
2. Existing systems without groundwater
monitoring wells and flows above 15,000 gpd. The department may require the
owner or operator of a system which has had a monthly average liquid waste flow
to land treatment equal to, or greater than, 15,000 gallons per day (gpd),
anytime during the previous year, to demonstrate compliance with the
appropriate groundwater standards by installing a department approved
monitoring well system. The monitoring well system installation will be
required through the modification or reissuance of the discharge permit for the
system.
3. Existing systems without
groundwater monitoring wells and flows below 15,000 gpd. The owner or operator
of a system which has monthly average liquid waste flows to land treatment of
less than 15,000 gpd shall demonstrate that granting the exemption will result
in the treatment system having a low potential for exceeding the groundwater
standards of ch. NR 140. The department shall require all feasible upgrading
and operational improvements that will optimize the performance of the existing
land treatment system and minimize groundwater impacts. Such improvements may
include, but are not limited to, operational changes, site modifications and
minimizing the waste loading. Systems in this size category that the department
judges as having a high potential for groundwater contamination will be
required to install a groundwater monitoring well system. The department shall
consider pollutant loading rates, soil types and system location in assessing
the potential for groundwater contamination.
4. New or expanded land treatment systems.
The owner or operator of a new or expanded land treatment system may utilize
information from research studies, literature or similar existing land
treatment systems in the demonstration for a variance. The department may
require the installation of a groundwater monitoring well network to check for
groundwater impacts from land treatment on the site.
(2) SUBMITTING AN EXEMPTION
REQUEST. The owner or operator of a land treatment system shall request an
exemption from a requirement of this chapter by submitting facts to the
department:
(a) In the application for
issuance, reissuance or modification of a WPDES permit, or
(b) In plans and specifications for a new or
expanded land treatment system or during the 90-day plan approval period as
specified in s.
281.41, Stats.,
or
(c) During the 30-day public
comment period following public notice by the department of intent to issue,
reissue or modify a WPDES permit under s.
283.31,
Stats., or
(d) At a public hearing
held under s.
283.49 or
283.63,
Stats.
(3) WRITTEN
EXEMPTIONS. All exemptions issued under this section shall be granted in
writing.
