Containment and Disposal of Waste Water in HP and UHPWJ Operations. Richard A. Burgess KTA-Tator, Inc. Containment and Disposal of Waste Water in HP and UHPWJ Operations. Overview of HPWJ & UHPWJ Surface Preparation Waste Generation Issues Unique to HPWJ & UHPWJ
Richard A. Burgess
Waterjetting (WJ): Use of standard jetting
water discharged from a nozzle at pressures of 70 MPa (10,000 psig) or greater to prepare a surface for coating or inspection.
Water Cleaning (WC): Use of pressurized
water discharged from a nozzle to remove unwanted matter from a surface.
Low-Pressure Water Cleaning (LP WC):
High-Pressure Water Cleaning (HP WC):
High-Pressure Waterjetting (HP WJ):
Waterjettingperformed at pressures from 70 to 210 Mpa (10,000 to 30,000 psig).
Ultrahigh-Pressure Waterjetting (UHP WJ):
Waterjetting performed at pressures above 210 Mpa (30,000 psig).
Joint Surface Preparation Standard
SSPC-SP 12/NACE No. 5
Surface Preparation and Cleaning of Metals by
Waterjetting Prior to Recoating
Revised July 2002
(Dull Putty Knife Test)
1.4 Visual Reference Photographs: SSPC-VIS 4/NACE OperationsVIS 7, “Guide and Reference Photographs for SteelSurfaces Prepared by Waterjetting,” provides color photographs for the various grades of surface preparation as a function of the initial condition of the steel. The latest issue of the reference photographs should be used.
Flow 12.9 L/min (3.42 gpm)
Flow 8.3 L/min (2.2 gpm)
Flow 2.0 L/min (0.52 gpm)
Jets may not significantly erode the coatings- they are typically used for partial removal or for cleaning loose detritus
Jets erode the coatings fairly rapidly- typically used for partial removal.
Jets erode and destroy coatings very fast -typically used when most or all of the coating is to be removed
PSI GPM Lbs/Hra Ft3/Hr
10,000 3.4 1700 27.4
20,000 2.2 1102 17.6
40,000b 2 260 4.2
a-A gallon of water weighs 8.34 lbs.
b-At this level of energy surfaces dry quickly due to heat
Selective stripping of outer hull coatings open-cycle, hand held lance-
39 ft2/hr/gun - 89 ft2/hr/gun.
Sweep and spot “water-blast” inside of tanks with hand-held lances-
157 ft2/hr/gun - 171 ft2/hr/gun
Sweep and spot “water-blast” of outer hull coatings with hand-held lances –
Average, 198 ft2/hr/gun
Complete removal of severely damaged outer hull coatings with hand-held lances-
Average, 152 ft2/hr/gun
Complete removal of non-skid flight deck to bare metal closed loop machine-
Average, 134 ft2/hr/unit.
Complete removal of outer hull coatings to bare metal open-cycle machine-
Average, 471 ft2/hr/unit.
Separating Lead in Wash Water by Physical Means
Example- All Lead
Dissolved Metals, 0.45µ filter
Water washing of the bridge for the purpose of removing chalk, dirt, grease, oil, bird nests, and other surface debris can be performed without additional containment provided paint chips and removed debris are removed and collected prior to washing or are cleaned from the site after cleaning is completed each day.
At the Contractor’s option, SSPC Class 4W permeable containment materials described above under “Water Jetting or Wet Abrasive Blast Cleaning for the Removal of Paint” can be used to collect the debris while the washing is underway.
Water washing of the bridge for the purpose of removing chalk, dirt, grease, oil, bird nests, and other surface debris, and water jetting or wet abrasive blast cleaning for the purpose of removing paint and surface debris shall be conducted within a containment designed, installed, and maintained in order to capture and contain all water and waste materials. (SSPC Class 2W-3W)
When water is used for surface cleaning, the collected water shall be filtered to separate the particulate from the water. Recycling of the water is preferred in order to reduce the volume of waste that is generated.
The water after filtration shall be collected and disposed of according to the waste handling portions of this specification.
When a slurry is created by injecting water into the abrasive blast stream, the slurry need not be filtered to separate water from the particulate.
Waste water generated from bridge washing, hygiene purposes, and cleaning of equipment shall be filtered on site to remove particulate and disposed of at a Publicly Owned Treatment Works (POTW) according to State regulations.
The Contractor shall provide the Engineer with a letter from the POTW indicating that they will accept the waste water. If the POTW allows the filtered water to be placed into the sanitary sewer system, the Contractor shall provide a letter from the POTW indicating that based on the test results of the water, disposal in the sanitary sewer is acceptable to them.
Water shall not be disposed of until the above letter(s) are provided to, and accepted by, the Engineer.
Natural Evaporation of Waste Water (CAP)
On-site Treatment and discharge (Treatment Plant)
Drying, Sludge Cake
Solid Waste- Sample, Test and Classify