NR 110.22(4)(a)4.e.e. Rubber boots; and
NR 110.22(4)(a)4.f.f. Safety harness and line.
NR 110.22(4)(a)5.5. Warning signs shall be installed where appropriate.
NR 110.22(4)(b)(b) Storage requirements.
NR 110.22(4)(b)1.1. The materials used for storing of hazardous chemicals shall be selected based on the physical and chemical characteristics of each chemical used.
NR 110.22(4)(b)2.2. Chemical storage areas shall be enclosed by dikes or curbs which will contain the stored volume in case of a spill until it can be either safely transferred to another storage area or released to the wastewater at a controlled rate which will not damage the treatment facilities, inhibit the treatment processes, or contribute to stream pollution. Liquid polymer shall be similarly contained.
NR 110.22(4)(b)3.3. Chemical storage and mixing areas shall be separate from other treatment plant functions.
NR 110.22(4)(b)4.4. Nonslip floor surfaces are desirable in polymer handling areas.
NR 110.22(4)(c)(c) Pumping and piping requirements.
NR 110.22(4)(c)1.1. The materials used for piping, valves, pumping, metering, splash guards and any other equipment used to convey hazardous chemicals shall be selected based on the physical and chemical characteristics of each chemical used.
NR 110.22(4)(c)2.2. All piping containing or transporting hazardous chemicals shall be identified with labels every 3 meters (10 feet) and with at least 2 labels in each room, closet or pipe chase. Color coding may also be used but is not an adequate substitute for labeling.
NR 110.22(4)(c)3.3. All pumps or feeders for hazardous or corrosive chemicals shall have splash guards which will effectively prevent spray of chemicals into space occupied by workers. The splash guards are in addition to guards to prevent injury from moving or rotating machinery parts. All connections except those adjacent to storage or feeder areas shall have guards which will direct any leakage away from space occupied by workers.
NR 110.22(4)(c)4.4. Exposed pipes containing hazardous chemicals may not be located above shoulder level except where continuous drip collection trays and coupling guards will eliminate the spraying or dripping of these chemicals onto workers.
NR 110.22(5)(5)Physical treatment.
NR 110.22(5)(a)(a) Design. Physical treatment shall be evaluated on a case-by-case basis. The design shall be based on pilot plant studies or operating experience.
NR 110.22(5)(b)(b) Filtration.
NR 110.22(5)(b)1.1. Selection of type, size, and depth of filter media shall depend on the filtration rate, the type of treatment provided prior to filtration, filter configuration, available hydraulic head, and the desired effluent quality.
NR 110.22(5)(b)2.2. Multiple filters shall be provided.
NR 110.22(5)(b)3.3. For high rate effluent filtration, the filtration rate at maximum hour design flow may not exceed 3.4 liters per second per square meter (5 gallons per minute per square foot). The filtration rate shall be calculated on the total available filter area with one filter unit out of service.
NR 110.22(5)(b)4.4. Provisions shall be made for backwashing each filter. The backwash system shall be capable of providing a variable backwash rate with a maximum rate sufficient to fluidize the filtering material. A minimum backwash period of 10 minutes shall be provided.
NR 110.22(5)(b)5.5. Air scour for aiding backwashing is recommended.
NR 110.22(5)(b)6.6. Provision shall be made for chlorinating each filter.
NR 110.22(5)(b)7.7. Backwash reservoirs shall be provided. Total backwash water storage provided shall equal or exceed the volume required for 2 complete backwash cycles.
NR 110.22(5)(b)8.8. Spent backwash water shall be individually treated or returned to the head of the treatment facility. The return rate of backwash to the head of the treatment facility may not exceed 15% of the average design flow rate.
NR 110.22(5)(c)(c) Microstraining.
NR 110.22(5)(c)1.1. Multiple screening units shall be provided.
NR 110.22(5)(c)2.2. The screening rate at maximum daily design flow may not exceed 3.4 liters per second per square meter (5 gallons per minute per square foot) based on submerged area with one screening unit out of service.
NR 110.22(5)(c)3.3. Provisions shall be made for backwashing each unit. The backwash system shall be capable of delivering at least 1.7 liters per second per meter (8 gallons per minute per foot) of filter length. Backwash shall be delivered at 4.2 kilograms force per square centimeter (60 pounds per square inch).
NR 110.22(5)(c)4.4. Spent backwash shall be individually treated or returned to the head of the treatment facility. The return rate of backwash to the head of the treatment facility may not exceed 15% of the average design flow rate.