High-pressure Washing Research Articles

Evaluation of an industry-based sanitation protocol for transport vehicles contaminated with porcine reproductive and respiratory syndrome virus

Objective: To test a protocol, using conditions found on commercial swine production units, for sanitation of 1:150 scale models of commercial transport vehicles contaminated with porcine reproductive and respiratory syndrome virus (PRRSV). Methods: Model trailers were experimentally contaminated with PRRSV MN 30-100 and either pressure-washed with cold water alone (Treatment 1) or washed and then disinfected with modified potassium monopersulfate (Treatment 2), quaternary ammonium chloride (Treatment 3), or a phenolic product (Treatment 4), each applied using a hydrofoamer. In Phase One, the presence of PRRSV RNA was evaluated by polymerase chain reaction (PCR) testing of swabs collected from the trailers’ interiors immediately after washing and 30, 60, 90, and 120 minutes post treatment. In Phase Two, the presence of viable PRRSV was evaluated by swine bioassay (injection of supernatants from PCR-positive swabs) and housing pairs of sentinel pigs in treated trailers for 2 hours, beginning 90 minutes post treatment. Results: Swabs were PCR-positive 120 minutes post treatment in 18 of 20 trailers receiving Treatment 1, none of 20 trailers receiving Treatments 2 and 3, and two of 20 trailers (suspect reactions) receiving Treatment 4. Viable virus was detected both by swine bioassay and sentinel pig exposure protocols in trailers receiving Treatment 1, and by swine bioassay alone in trailers receiving Treatment 4. Implications: High-pressure washing of transport trailers, followed by 90 to 120 minutes exposure to either modified potassium monopersulfate or quaternary ammonium chloride disinfectants applied with a hydrofoamer is likely to eliminate residual infectious PRRSV.

Suppression of deicing salt corrosion of weathering steel bridges by washing

To elucidate the influences of deicing salts and high pressure (2–4 MPa) washing on the characteristics of the rust formed on weathering steel bridges, washing experiments have been carried out for three years. The rust was characterized by means of ion chromatography, X-ray diffraction and adsorption of N 2. The rust thickness was measured, and also the rust weight per unit area of the steel surface was measured. It was found that water-soluble chloride accelerated the rate of corrosion because the rust particles grow by the chloride ions and micro-pore structure of the rust appeared by the chloride ions. Washing with water suppressed corrosion owing to the disappearance of chloride ions.

THE BEHAVIOUR AND TREATMENT OF ORIMULSION® BITUMEN STRANDED ON PEBBLE, COBBLE OR IMPERMEABLE SUBSTRATE SHORELINES

ABSTRACT Bitumen from an Orimulsion® spill can strand on shorelines in the form or dispersed bitumen or coalesced bitumen. Wetness of the shoreline substrate is an important factor in the adhesion of the bitumen and this in turn significantly effects selection of a treatment technique. Stranded bitumen on the surface of a shoreline that remains wet and/or non adhesive can be removed relatively easily by a combination of low-pressure washing, flooding, and recovery, or by manual and mechanical removal techniques. When stranded on dry surfaces or when interfacial surfaces dry, then the bitumen will strongly adhere to shoreline substrates either in the form of thin coatings or thick deposits of bitumen that are difficult to remove. Heated, high-pressure seawater washing is effective but must be accompanied by flooding to minimize penetration into coarse sediments. Sediment relocation, sediment removal, wet tilling and natural recovery techniques are appropriate techniques under specific oiling conditions. Temperature greatly effects bitumen penetration into sediments. Where bitumen coatings or deposits form in subsurface sediments then treatment becomes extremely difficult, requiring sediment removal or techniques to bring oiling surface sediments to the surface for treatment.

A Novel Nonchemical Method for Quarantine Treatment of Fruits: California Red Scale on Citrus

A process for removing or killing California red scale, Aonidiella aurantii (Maskell), from citrus fruit as a postharvest treatment was evaluated. The process subjects the fruit to vacuum, steam, and vacuum that physically removes red scale from the fruit and kills those scales that are not removed from the fruit. Different numbers of cycles and steam temperatures were compared for efficacy in removing scale from lemons or killing those that remained. Multiple (two to three) cycles removed up to 96% of first molt scales on the fruit, but they were much less effective in removing other stages, especially those that had advanced beyond the second instar. However, it was extremely effective in killing the scales remaining on the fruit. Although this process does not eliminate cosmetic damage caused by scale presence, it might be used in combination with high-pressure washers currently used in packing houses to allow importers and exporters to meet the most stringent quarantine requirements. Because of its killing power, this technique should be tried on other insects and commodities to see whether it can be substituted for certain uses of methyl bromide.

A Novel Nonchemical Method for Quarantine Treatment of Fruits: California Red Scale on Citrus

A process for removing or killing California red scale, Aonidiella aurantii (Maskell), from citrus fruit as a postharvest treatment was evaluated. The process subjects the fruit to vacuum, steam, and vacuum that physically removes red scale from the fruit and kills those scales that are not removed from the fruit. Different numbers of cycles and steam temperatures were compared for efficacy in removing scale from lemons or killing those that remained. Multiple (two to three) cycles removed up to 96% of first molt scales on the fruit, but they were much less effective in removing other stages, especially those that had advanced beyond the second instar. However, it was extremely effective in killing the scales remaining on the fruit. Although this process does not eliminate cosmetic damage caused by scale presence, it might be used in combination with high-pressure washers currently used in packing houses to allow importers and exporters to meet the most stringent quarantine requirements. Because of its killing power, this technique should be tried on other insects and commodities to see whether it can be substituted for certain uses of methyl bromide.

Hydrothermal synthesis, structure and photocatalytic property of nano-TiO2-MnO2

TiCl4 and MnSO4· H2O as raw materials are hydrolyzed stiochiometrically, following the intermediate of oxide hydrating reacts at 150°C, 0.5 MPa in high-pressure reactor, after filtering, washing and drying, nanometric TiO2-MnO2 (Ti1-XMnXO2) is prepared. The effects of the reaction temperature and time on nanometric TiO2-MnO2 are also discussed. XRD shows that the product is TiO2-MnO2 with amorphous phase. After being sintered at above 780 °C, it transfers into Ti1-XMnXO2 with a rutile structure. TEM shows that TiO2-MnO2 is the spherical particle. And the average diameter of the particles is 20 nm. The optical absorbance was determined by UV-265 spectrophotometer after dispersing the sample in the mixture of water and glycerol with the ratio of 1 : 1 equably. It is found that the nano-material possesses the advantages of both nano-TiO2 and nano-MnO2, and it has strong absorption in the UV and visible region. Photodegradation of dyes in an aqueous solution is investigated using nanometricTiO2-MnO2 as a photocatalyst. The results show that after 60 min illumination, the decolorization rate of the acidic red B and acidic black 234 dye can be as high as 100%.

High-pressure washing device

High-pressure washing device

Effect of Pressure and Dwell Time on Efficiency of a High-Pressure Washer for Postharvest Removal of California Red Scale (Homoptera: Diaspididae) from Citrus Fruit

The most common economic injury caused by California red scale, Aonidiella aurantii (Maskell), to citrus is downgrading of fruit caused by the presence of scale on the fruit. In the packinghouse, scale can be removed from fruit by subjecting the fruit to high-pressure water sprays that physically dislodge the scale. In this study, we evaluated a FMC Freshgard 4000 washer at several pressures and dwell times (the time from when a fruit enters the high-pressure washer to when it exits) for scale removal. Removal of total scale (live and dead) at 22.1, 13.6, and 10.2 atmospheres was 97–99.9, 95–98, and 97%, respectively. Live scale (which comprised 13–21% of scale on fruit before treatment) were more difficult to remove by high-pressure washing than dead scale. Removal of live scale at 22.1, 13.6, and 10.2 atmospheres was 93–99.7, 88–97, and 92% of live scale, respectively. The previously recommended pressure was 22.1 atmospheres, but results of this study support changing the recommended pressure to 10.2–13.6 atmospheres because the washer is almost as effective at these pressures as it is at 22.1 atmospheres. The advantage of slightly greater scale removal at 22.1 atmospheres compared with 13.6 and 10.2 atmospheres is offset by greater probability of causing economically significant injury to the fruit at higher pressures. Dwell time also affected scale removal. As dwell time increased 2.3-fold from 10–23 s, the number of scale remaining decreased by 6.1-fold.

Lessons from 10 Years of Post-Exxon Valdez Monitoring on Intertidal Shorelines

ABSTRACT Intertidal shorelines impacted by the Exxon Valdez oil spill have been monitored by the National Oceanic and Atmospheric Administration (NOAA) since late 1989. Originally intended to document oil fate and impacts of hot-water high-pressure washing, the program evolved into a comprehensive examination of long-term recovery processes in these environments. Annual field sampling and laboratory and statistical analyses are combined to document trends in biology, chemistry, and geomorphology of 26 sites in Prince William Sound. Recovery processes in shoreline ecosystems occur over different time frames, depending on the particular measure and scale used. Using a geomorphological measure, most boulder/cobble sites where berm relocation was carried out to remove subsurface oil took 1–2 years to return to pre-treatment configurations. Mean levels of polyaromatic hydrocarbons in mussels from oiled sites remained elevated for approximately 3–4 years after the spill. Abundance trends for most epibiota species at mid intertidal zones from oiled sites were parallel to those from unoiled sites after 1–2 years. Longer lasting impacts were found for infaunal species at low elevations, perhaps related to changes in grain size composition at washed sites. Some impacts from oiling remained at sensitive sites through at least 1997, including subsurface oiling, species abundance differences, and patchy areas of sediment and bivalve contamination from polyaromatic hydrocarbons.

The influence of three methods of gravel cleaning on brown trout, Salmo trutta , egg survival

Siltation of spawning gravels in upland rivers appears to be an increasing hindrance to salmonids' spawning success. River managers seek an effective and non-labour intensive means of loosening gravel and reducing fine material, so improving spawning success; this study compared three practical gravel cleaning techniques, applied at realistic (rather than intensive) levels, by assessing survival to hatching of buried brown trout, Salmo trutta L., ova at five sites on four rivers with gravel substrate in southern England. Each site consisted of six reaches, of which three were cleaned by tractor rotovating, high pressure jet washing and pump washing; these were compared with adjacent, untreated reaches. Brown trout ova were buried in both fine mesh and coarse mesh boxes in each reach. Significant improvements (at P<0·05) in survival (number of live alevins) were found in three of the five pump washed reaches, two of the five tractor rotovated reaches and one pressure washed reach when the data were analysed by site. When data from all five sites were analysed together, all treated reaches showed a significant improvement (at P<0·05) in egg survival to hatching compared with control reaches for fine mesh egg boxes; for coarse mesh boxes only pump washed reaches showed such an improvement. We feel that pump-washing provides the most effective, inexpensive and suitably non labour-intensive means of improving gravel, although ultimately it may be better to reduce the silt load of rivers. Freeze core bed samples taken before and immediately after cleaning were analysed for silt content; pump washing and high pressure washing may have reduced the amount of fine material. Copyright © 1999 John Wiley & Sons, Ltd.

High-pressure washing treatments to remove obscure mealybug (Homoptera: Pseudococcidae) and lightbrown apple moth (Lepidoptera: Tortricidae) from harvested apples.

Mixed life stages of obscure mealybug, Pseudococcus viburni (Signoret), and late 1st-instar or early 2nd-instar lightbrown apple moth, Epiphyas postvittana (Walker), on 'Royal Gala' apples (Malus domestica Borkhausen) were exposed to standard packhouse processing with and without addition of high-pressure apple washer treatments. Insect removal and mortality were assessed. After standard packhouse processing approximately 60% of P. viburni remained on their host apples. The 2 high-pressure apple washer treatments (500 and 800 psi at 2.0 rods/s) were equally effective and significantly reduced the number of P. viburni on apples compared with the packhouse control. High-pressure apple washer removal by location decreased in the following order: calyx cavity outside the sepals > cheek approximately stem cavity > or = calyx beneath sepals. About half of the E. postvittana larvae infesting apples was removed by standard packhouse processing. Removal rates were similar for all locations on open-calyxed apples. However, no removal occurred from the calyx beneath the sepals if the apple calyx was closed. All 4 high-pressure apple washer treatments tested (500 and 800 psi at 1.0 and 2.0 rods/s) halved the number of larvae on the apple exterior relative to the packhouse control. The pattern of removal for larvae on open-calyxed apples was calyx outside sepals approximately stem cavity > calyx beneath the sepals approximately cheek. A similar pattern was evident for larvae on closed-calyxed apples, except insects beneath the sepals evaded removal. The persistence of insects on the apple cheek reflects the high proportion of larvae inside tunnels in this location compared with other apple locations. Removal of internally positioned insects was much lower than that of externally positioned insects.

Basic investigation of integrating a membrane unit into high-pressure decaffeination processing

Abstract Within the large-scale industrial decaffeination processes using supercritical CO 2 , caffeine is stripped from the extracting agent CO 2 with water using a high-pressure washing tower. On account of the value of the product, the caffeine is recovered from the washwater with a distillation–crystallization process. A reverse osmosis membrane process appears to be very suitable to replace the energy consuming distillation step to recover the caffeine and supply a cleaned water stream to be returned to the washing tower. Although this combination of a membrane process with high-pressure extraction was suggested earlier, very little fundamental work and experimental data have been published so far. The presented study is concentrated on basic investigations of this process. The osmotic pressure of aqueous caffeine solutions was determined with cryoscopy and additional membrane experiments. Membrane test cells were used to study the maximum separation of binary caffeine–water solutions. The influence of temperature, pressure and caffeine concentration on membrane flow and rejection was investigated for commercially available RO flat sheet membranes. The results show that RO concentration of aqueous caffeine solutions is feasible with moderate pressures and temperatures up to 60°C. Additional experiments with a non-optimized plate module supplemented the investigation of separation performance with approximately 50% of the test cell flux. Flux measurements with an agitated membrane cell show that the permeation of water with high CO 2 concentrations impairs membrane performance. A reverse osmosis washwater recycling process should flash the washwater to atmospheric pressure before the membrane unit.

Response of Citrus Fruit to High-pressure Washing

The effect of high-pressure washing (HPW) on the surface morphology and physiology of citrus fruit was examined. Mature white (Citrus paradisi Macf. `Marsh') and red (Citrus paradisi Macf. `Ruby Red') grapefruit, oranges (Citrus sinensis L. `Hamlin'), and tangelos (Citrus reticulata Blanco × Citrus paradisi Macf. `Orlando') were washed on a roller brush bed and under a water spraying system for which water pressure was varied. Washing white grapefruit and oranges for 10 seconds under conventional low water pressure (345 kPa at cone nozzle) had little effect on peel wax fine structure. Washing fruit for 10 seconds under high water pressure (1380 or 2760 kPa at veejet nozzle) removed most epicuticular wax platelets from the surface as well as other surface debris such as sand grains. Despite the removal of epicuticular wax, HPW did not affect whole fruit mass loss or exchange of water, O2, or CO2 at the midsection of the fruit. Analysis of the effect of nozzle pressure (345, 1380, or 2760 kPa), period of exposure (10 or 60 seconds), and wax application on internal gas concentrations 18 hours after washing showed that increasing nozzle pressure increased internal CO2 concentrations while waxing increased internal ethylene and CO2 concentrations and decreased O2 concentrations. An apparent wound ethylene response was often elicited from fruit washed under high pressures (≥2070 kPa) or for long exposure times (≥30 seconds).

High-performance gamma-spectroscopy measurements of equipment retrieved from Hanford Site high-level nuclear waste tanks

The cleanup of high-level defense nuclear waste at the Hanford Site presents many challenges. These include removing and disposing of components from buried active waste tanks to allow new equipment insertion or hazards mitigation. This paper discusses a unique automated system that provides for retrieval, high-pressure washing, inventory measurement, and containment for disposal. Key to the inventory measurement is a three-detector high-purity germanium high-performance gamma-spectroscopy system capable of recovering data at up to 90-percent saturation (200,000 counts/s). Data recovery is based on a unique embedded electronic pulser and special software to report the inventory. Each detector has different shielding specified through simulation using the Monte Carlo computer code for N-particle transport modeling. This shielding provides performance over a dynamic range of eight orders of magnitude. This paper covers system description, calibration issues, and operation.

Comparison of Water Wash, Trimming, and Combined Hot Water and Lactic Acid Treatments for Reducing Bacteria of Fecal Origin on Beef Carcasses

Cleaning treatments, such as high-pressure water wash at 35°C or trim, alone and combined with sanitizing treatments, such as hot water (95°C at the source), warm (55°C) 2% lactic acid spray, and combinations of these two sanitizing methods, were compared for their effectiveness in reducing inoculated numbers (5.0 to 6.0 log CFU/cm2) of Salmonella typhimurium, Escherichia coli O157:H7, aerobic plate counts, Enterobacteriaceae, total coliforms, thermotolerant coliforms, and generic E. coli on hot beef carcass surface areas in a model carcass spray cabinet. Log reductions in numbers of all tested organisms by water wash or trim alone were significantly smaller than the log reductions obtained by the different combined treatments. Regardless of the cleaning treatment (water wash or trim) or surface area, the range for mean log reductions by hot water was from 4.0 to >4.8 log CFU/cm2, by lactic acid spray was from 4.6 to >4.9 log CFU/cm2, by hot water followed by lactic acid spray was from 4.5 to >4.9 log CFU/cm2, and by lactic acid spray followed by hot water was from 4.4 to >4.6 log CFU/cm2, for S. typhimurium and E. coli O157:H7. Identical reductions were obtained for thermotolerant coliforms and generic E. coli. No differences in bacterial reductions were observed for different carcass surface regions. Water wash and trim treatments caused spreading of the contamination to other areas of the carcass surface while providing an overall reduction in fecal or pathogenic contamination on carcass surface areas. This relocated contamination after either water wash or trim was most effectively reduced by following with hot water and then lactic acid spray. This combined treatment yielded 0% positive samples for S. typhimurium, E. coli O157:H7, thermotolerant coliforms, and generic E. coli on areas outside the inoculated areas, whereas percent positive samples after applying other combined treatments ranged from 22 to 44% for S. typhimurium, 0 to 44% for E. coli O157:H7, and 11 to 33% for both thermotolerant coliforms and generic E. coli. From data collected in this study, it is possible to choose an effective, inexpensive treatment to reduce bacterial contamination on beef carcasses. In addition, the similar reduction rates of total coliforms, thermotolerant coliforms, or generic E. coli may be useful in identifying an indicator to verify the effectiveness of the selected treatment as a critical control point in a Hazard Analysis and Critical Control Point program.

SEA EMPRESS SPILL: IMPACTS ON MARINE AND COASTAL HABITATS

ABSTRACT Oil from the Sea Empress spill in February 1996 contaminated more than 120 miles of South Wales coastline, including rocky shores, sand and shingle shores, mudflats, and salt marsh. Some aerosol sprays also contaminated some maritime cliff along wave-exposed coasts. Some areas of shore, including areas with a high nature conservation value, were heavily oiled. Although much of the affected shore lies on the open coast and is exposed to wave action, large amounts of oil remained on the shores for many months, becoming buried and bound with sediments, percolating deep into cobble and shingle shores, and pooling behind rock features. Oil persistence has been greatest on sheltered shores, particularly where heavy fuel oil stranded. Cleanup activities on these shores have included the use of dispersants, high-pressure washing, low-pressure deluge, trenching, and berm relocation. Numerous studies of the effects of the oil and the cleanup techniques on the intertidal and coastal communities are being undertaken by biologists from various organizations. This paper presents a summary of the results so far.

High Pressure Washing to Remove Decayed Tissue and Improve Quality of Clingstone Peach Puree

ABSTRACTPhysical and chemical characteristics were evaluated on brown rot and phomopsis decayed tissue in peaches, to investigate its removal by washing with high pressure water sprays and to evaluate quality of puree made after washing. Washing treatments were at 345 to 758 kPa for up to 10, 1‐s exposures. Results indicated brown rot tissue was darker, less yellow and had more soluble solids than the softer phomopsis decayed tissue. Nearly 100% of phomopsis decayed and 70% of brown rot tissue were removed with high pressure water treatment. Removal improved the quality of peach puree, but medium/large lesions were more detrimental to quality than small lesions.

Evaluation of a High-Pressure Washer for Postharvest Removal of California Red Scale (Homoptera: Diaspididae) from Citrus Fruit

A device for removing California red scale, Aonidiella aurantii (Maskell), from citrus fruit as a post harvest treatment in the packinghouse was evaluated. The device subjects fruit to high-pressure water sprays that physically dislodge red scale from the fruit. Different pressures and different durations of treatment were compared for efficacy in removing red scale from navel oranges. The washer removed up to 98% of the scale on the fruit, and was equally effective in removing either live or dead scale. The primary economic damage of red scale on citrus is cosmetic injury caused by scale being present on the fruit, and the washer is an effective non chemical method for reducing this injury. Adoption of this commercially available device by the California citrus industry may increase the economic threshold for red scale.

Physiological Responses of Citrus to High-pressure Washing

High-pressure washing (&gt;689 to 3446 kPa or 100 to 500 psi at the spray nozzle) has been used recently in citrus packinghouses to improve the action of surfactant solution and brushing on the removal of dirt and superficial molds. Although high-pressure washing has no obvious detrimental effect on citrus fruit (e.g., no cellular breakage), its effects on physiology have not been fully examined. In this study gas samples were taken from the fruit core of `Orlando' tangelos, `Hamlin' oranges, and `Ruby Red' and white `Marsh' grapefruit prior to and following washing. An apparent wound ethylene response was measured for all varieties and was a function of prolonged exposure (&gt;20 s) and excessive pressure (&gt;2067 kPa). For the responding fruit, internal ethylene was initially detected about 3 h after washing, reached a maximum around 24 h (range: 0.1 to 0.6 ppm), and diminished to near background levels (0.0 ppm) after 48 h. No wound ethylene was observed when fruit were washed for the recommended exposure time (10 s) and pressure (1379 kPa). Concurrent decreases in internal O2 and increases in CO2 were observed for white and red grapefruit. High-pressure washing (1379 or 2757 kPa) did not affect water loss and water, O2, and CO2 exchange. The effects of subsequent waxing of the fruit (increased internal ethylene and CO2 levels and reduced of internal O2 levels) were amplified by washing at the higher pressure (2757 kPa).

Performance characteristics of three different pre-evisceration wash regimes applied to the forequarters of ovine carcasses in an inverted dressing system

The performance of three pre-evisceration wash regimes applied to the forequarters of ovine carcasses in an inverted dressing system was assessed. Washing regimes consisted of a high-pressure jet wash, a low-pressure sluice wash, and both washes applied in series. Visible contamination incidences prior to the wash were between 64 and 71% at the carcass level; wool was the predominant contaminant, while faecal material and ingesta were rare. All wash regimes reduced the incidence of carcass contamination by 62·8 to 70·5%, primarily through the removal of wool. A secondary effect was the redistribution of some wool from other areas of the forequarter to the inside leg. The sluice wash was superior to the jet wash in removing visible contamination. Bacterial numbers ranged from 3·64 to 4·03 log 10CFU/cm 2 prior to washing and were reduced to between 3·24 and 3·75 log 10CFU/cm 2 immediately after the pre-evisceration wash; the three wash regimes performed in an equivalent, but commercially non-significant manner. Further reductions of between 0·20 and 0·58 log 10CFU/cm 2 were effected by post-dressing events, including 12 h chilling. The low-pressure wash performance was considered superior to that of the jet wash, and no further improvement in carcass quality was demonstrated by the use of both washes in series.