Wisconsin Administrative Code › Department of Natural Resources › NR 800 - Environmental Protection - Water Supply › Chapter NR 811 - Requirements For The Operation And Design Of Community Water Systems › Subchapter VI - Chemical Addition › Section NR 811.40 - Storage and handling

Current through June 24, 2024
Specific requirements regarding storage and handling are
					 provided in the sections covering the particular chemical. Storage and handling
					 installations shall meet the following general requirements:
(1) STORAGE FACILITIES. Storage facilities
				  shall meet the following requirements:
(a)
				  Space shall be provided for at least 30 days of chemical supply, convenient and
				  efficient handling, dry storage conditions, and a minimum of 1.5 truck loads
				  storage volume where purchase is by truck load.
(b) Covered or unopened shipping containers
				  shall be provided for storage unless the chemical is transferred into an
				  approved covered storage unit. Solution tanks shall have overlapping or
				  threaded covers that provide sanitary protection for the chemical being stored.
				  Large tanks shall be covered and those with top access openings shall have
				  either threaded covers or the openings shall be curbed and fitted with
				  overlapping covers. Grommets, pipe seals, or other sanitary means shall be
				  provided to create a sanitary seal where tubes, hoses, and pipes pass through
				  the walls or covers of chemical storage tanks.
(c) Solution storage or day tanks supplying
				  chemical feeders directly shall have at a minimum sufficient capacity for one
				  day of operation. If the chemical solution is prepared from a powder or slurry,
				  2 solution tanks shall be required if necessary to assure continuity of
				  feed.
(cm) Graduated lines may not
				  be used to determine daily chemical usage when the daily use is less than 5
				  percent of the tank capacity.
(d)
				  Solution storage or day tanks supplying feeders directly shall have a maximum
				  capacity such that daily chemical solution usage is a minimum of 5 percent of
				  the tank capacity. The department may approve chemical container storage
				  volumes that will allow daily chemical solution usage less than 5 percent of
				  the tank capacity if supporting information is provided to the department and
				  the chemical storage container is placed on a scale, or another department
				  approved method is installed, to accurately determine daily chemical usage.
				  Graduated lines shall not be used to determine daily chemical usage in cases
				  when the daily use is less than 5 percent of the tank capacity. The maximum
				  storage volume shall not exceed 45 days for sodium hypochlorite and 60 days for
				  all other chemicals.
(e) Storage
				  facilities shall be constructed of, or lined with, materials compatible with
				  the chemical being handled.
(f)
				  Mixing equipment shall be provided where necessary to assure a uniform chemical
				  solution strength. Continuous mixing shall be provided to maintain slurries in
				  suspension.
(g) Means shall be
				  provided to accurately determine the amount of chemical applied in accordance
				  with s.
				  NR 811.39
				  (6).
(h) For non-bulk tanks, suction lines shall
				  extend into the tank through the tank cover. Chemical feed pumps shall be
				  installed at a height above the maximum liquid level in the chemical storage
				  tank. Flooded suctions, for bulk tanks and if necessary to prevent loss of
				  prime, may be approved by the department on a case-by-case basis.
(i) Adequate means of draining tanks shall be
				  provided, but there may be no direct connection between any drain piping and a
				  sanitary sewer. Chemicals shall not be discharged directly to a storm sewer.
				  Drain piping shall terminate at least 2 pipe diameters, but not less than 3
				  inches, above the overflow rim of a receiving sump, conduit or waste
				  receptacle.
(j) Overflow pipes, if
				  provided, shall be turned downward, provided with a 24-mesh corrosion resistant
				  screen, have a free air break discharge, and be located in a conspicuous
				  location.
(k) If subsurface
				  locations for solution or storage tanks are approved by the department, the
				  tanks shall be free from sources of possible contamination and located to
				  assure positive drainage for groundwater, accumulated water, chemical spills,
				  and overflows.
(l) Chemicals shall
				  be stored in accordance with the following requirements:
1. Each chemical shall be provided with its
				  own secondary leakage containment.
2. Each of the following chemicals shall be
				  stored in a separate room with no other chemicals:
a. Fluoride.
b. Ammonia.
c. Powders.
d. Gases.
(m) All buried chemical solution lines and
				  gas lines shall be installed within protective conduit piping. Each chemical
				  solution line shall be placed in its own protective conduit piping.
Note:
When the chemical feed equipment will
					 not be installed near the point of chemical application it is recommended that
					 chemical solution piping be installed within protective conduit from the
					 chemical feed equipment to the point of chemical application.
(n) Gases from feeders, storage, and
				  equipment exhausts shall be conveyed to the exterior of the building above
				  grade and remote from air intakes to reduce the health and safety risk to
				  operators and reduce corrosion of equipment and facilities from chemical
				  vapors. Chemical vapor ventilation systems shall meet the following
				  requirements as applicable:
1. Fluoride and
				  ammonia liquid storage tanks shall be vented to the exterior of the building
				  but not through vents in common with day tanks.
2. Chemical tank vents, when provided, shall
				  be vented to the exterior of the building and terminate downward facing with a
				  24-mesh corrosion resistant screen. The tank vent shall terminate as high as
				  practical, but a minimum of 24 inches above surrounding grade.
(o) Permanent signs identifying
				  the chemical for each fill tube shall be posted at chemical offloading areas.
				  Permanent signs identifying the tank contents shall be posted adjacent to or on
				  chemical storage tanks.
(p)
				  Compliance with local, state, and federal safety codes, including department of
				  safety and professional services and OSHA codes, for other applicable chemical
				  safety and handling requirements is required.