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

(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:

(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:

(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.

(a) Equipment shall be provided for measuring quantities of chemicals used to prepare feed solutions.

(b) Piping for chemicals shall be compatible with the chemical being conveyed.

(c) The following equipment shall be provided for each installation where chemicals are handled:

(d) Provision shall be made for the transfer of dry chemicals from shipping containers to storage bins or hoppers in such a way as to minimize the quantity of dust generated. Control shall be provided by use of one of the following:

(e) Carts, elevators, or other appropriate means shall be provided for lifting chemical containers to minimize lifting by operators.

(f) Electrical equipment shall be used which will prevent explosions, particularly when using sodium chlorite and activated carbon. Equipment shall comply with ch. SPS 316.

(g) Procedures for disposing of empty bags, drums, carboys, or barrels shall minimize exposure to dusts or chemicals.

(h) Acids shall be kept in closed, acid-resistant shipping containers, or storage units. Transfer from shipping containers to solution or day tanks shall be through acid resistant hose or pipe by means of a transfer pump.

(a) Shipping containers shall be fully labeled to include chemical name, purity, applicable NSF/ANSI standard approval in conformance with par. (b), concentration and supplier name and address.

(b) Chemicals shall meet the requirements of s. NR 810.09 (1).