| Water Jet Floor Cleaning and Effluent Recycling System | Australia | - | Full scale |
CONSTRUCTION # 2
Background:
SCS Specialised Services Pty Ltd, located in Camberwell, Australia, is a small floor cleaning and protective coatings industry, specialising in cleaning and refurbishment of medium to large factory floors. The company thoroughly cleans industrial concrete floors with the Recovery Jet to remove any build-up of soils, oils or other contaminants. In addition, the process opens the surface pores prior to any repair and coating activities.
Cleaner Production Principle:
Process modification; Housekeeping; Recovery, reuse and recycle.
Cleaner Production Application:
There are a number of existing methods for cleaning industrial concrete floors. These include high-pressure water jets, shot blasting, scrubbing, scarifying with wire brushes or cutters and chemical cleaning.
The proprietor of SCS, Mr Peter O'Shannessy, developed the system while working as a water jet contractor using spin jet cleaning heads. Although these heads cleaned the floor faster and more effectively than hand jetting, his experience was that it took twice as long to rinse the dirty water from the floors after cleaning, and that splashing prevented work being carried out around machines and stock. This limited cleaning to unoccupied buildings. There were also concerns about effluent disposal. This led to development of the idea of fitting a vacuum pickup to the spin jet head.
Each of these methods has some disadvantages, including airborne dust and storm water pollution, flooding and splashing, damage to the surface and poor cleaning results due to dirt remaining in cracks, holes and pores of the concrete. Because of its penetrating power, high-pressure water is the best method for cleaning a wide range of concrete floors.
SCS has developed a floor cleaning system (the Recovery Jet) that utilises high-pressure water spinning at high speed within an enclosed, lawnmower-style cleaning head, to overcome the problems of effluent management and floor flooding. The high-pressure water penetrates floor cracks and crevices and dislodges all dirt and loose materials. At the same time, the cleaning head is kept under vacuum to remove these particles and the water. This design eliminates water spray and flooding in most cases. There is no requirement to remove equipment or personnel from the area, therefore minimal disruption to the work place occurs. In contrast to hand water jetting or unenclosed rotary water jet cleaning, which discharge all the dirty water to either the floor drainage system or to external storm water drains, the SCS system directs the water, via the vacuum recovery system, to a truck-mounted recycling plant. Here, settling and filtration remove solids and the cleaned water is then returned to the cleaning head for reuse. Any oil in the water tends to become emulsified due to the high pressures used.
At the end of the cleaning operation, the recycled wastewater and sludge are pumped out for disposal at a licensed treatment facility.
Environmental and Economic Benefits:
The main advantage of the process is the significant reduction in wastewater generation. A normal high pressure cleaning system would generate between 20,000 and 40,000 litres of wastewater from cleaning an area of 600 square metres. The Recovery Jet system developed by SCS generates only 3,000 litres for the same floor area.
The process is also claimed to be at least four times faster than hand water jetting, which is a major benefit in reducing production downtime.
During the six-year period of development of the system, work was restricted to large companies because of the high cost of using the process. The cost has now been reduced from $7.00 per square metre to approximately $2.50 per square metre, which is price competitive with other methods.
Constraints:
After perfecting the system of vacuum pickup, the issue of wastewater disposal had to be confronted. It was not possible to gain approval from water authorities for onsite discharge of the wastewater to sewerage system without analysis being undertaken. For this reason, recycling of the water was considered.
Further difficulties were encountered in developing an effective recycling system that was small enough to fit onto a mobile truck. No complete technology existed for this process, and the final system was developed through trial and error, combined with innovative problem solving.
Contacts:
Review Status:
This case study was prepared in February 1997 by ACCP and has been reviewed by Environment Australia in May 1998 (see address above). It was edited for the ICPIC diskette in October 1998. It has not undergone a formal technical review by UNEP IE.
Subsequently, in March 1999 the case study underwent a technical review by Dr. Prasad Modak, Environmental Management Centre, Mumbai, India.