CASE STUDY: Distillation
WASH RECYCLING SYSTEMS – AN OVERVIEW OF THE PROCESSES THAT LED TO THE BSPG DECISION TO PROCEED THIS WAY
In early 2005 the Blue Star Print – New Zealand made a decision to investigate the possibility of supplying their four business units with a recycled wash.
The decision to do this was mainly down to two reasons:
- BSPG would significantly reduce their virgin wash purchases.
- BSPG would be taking another step towards becoming an environmentally active and conscious printing company.
The two main systems available for BSPG's consideration were filtration or distillation.
Filtration systems require that a specific wash type be used. This wash, once it has been used on press, is then allowed to settle in holding tanks. The specific chemistry of these washes allows for a separation of the waste wash and water parts after a set time and this occurs in these holding tanks. The two separate liquids are then micro filtered to remove any ink, paper, and other particle residues, before the water is disposed of into standard waste water systems, i.e. down the drain. The wash part is then ‘boosted’ with as much as 20% virgin material before being collected for reuse. The filter bags with the waste solids are disposed of with normal ink waste.
The recovery rate is usually around the 80% mark.
The system would have required BSPG to install one of these systems in each of its business units and they are restricted to the specific filterable wash type.
Distillation systems also recover around 80% of virgin purchases; however, their versatility is that they can process any type of wash. BSPG will not be restricted to using filterable washes that have sometimes shown to have lower than acceptable cleaning properties.
It also meant that BSPG, in association with Nova Inks & Chemicals had the option of out sourcing its wash recovery, there by saving significant outlay on capital equipment.
Nova had formed a partnership with Maratek Environmental, a Canadian based company with a long history in recovery systems, to bring their first distillation wash recovery system to Australasia. These systems have been making their mark in the North American market for the past decade and utilize PLC controlled low temperature distillation to recover virgin solvent from waste wash.
As the benefits of the system became clear, Nova proposed that it would handle all BSPG wash requirements, and with a three year contract agreed to, purchased a custom built unit from Maratek.
Nova will collect all waste wash from the four business units and process this waste through its newly acquired unit in a specially built “house”. Once processed the recovered solvent is again ‘boosted’, but this time with a specific cocktail of ingredients that will possibly contribute to a more efficient product than was started with. Even the water produced from the process is reusable, as the process produces significant quantities of distilled water.
The only disposable waste that is produced is 'sludge', made form ink, paper, and other particulates that are then disposed of in dedicated sites, and this accounts for less than 10% of all delivered waste product.
The benefits to BSPG are large, they can claim to be using an extremely environmentally friendly system which will supply them up to 80% of their wash needs as a recycled product, and they significantly reduced their virgin wash purchases at the same time.
Nova for their part was extremely enthusiastic about forming this unique supply arrangement, as it fits in nicely with their image of being a 'green' supplier to the printing industry in New Zealand.
Andrew Wilkinson
National Technical Manager
Nova Inks & Chemicals