Now it’s the turn of the Rijnstate hospital in Arnhem. Spurred by a feasibility study carried out by Wageningen UR, this hospital has drawn up a long list of items that, in the future, could be made from fermentable biobased materials.
The waste can be directly shredded in the wards, after which it is deposited in a fermentation tank via the sewers. The innovation generates energy, reduces waste production and improves hygiene and logistics
This could be the case at the Arnhem hospital by 2017, if all goes according to plan, says Marc Koster of the Real Estate department of Rijnstate. “We believe that by installing 51 shredders at various locations in the hospital we can shred disposable items and ferment them into biogas at a central location.”
The hospital hopes to incorporate the shredders into the hospital’s existing plans for capacity expansion.
Koster says that, in addition to benefitting the environment, there is a good business case for this solution: “We would earn on the investment and see a positive net cash value from day one and have recovered the entire investment within 11 years.” The inspiration for the fermentation process comes from the Reinier de Graaf hospital in Delft, which embraced the concept of the Pharmafilter company in 2012. In Delft, the shredder developed by Pharmafilter – called a ‘Tonto’ – has been handling ward waste such as meal leftovers, bedpans, blood bags and eating utensils for several years now.
The shredded products are moved to a central unit where solid matter and water are separated. The organic components then go to the fermenter, while indigestible components and conventional plastic end up in a sludge fraction. The watery fraction is purified in a membrane bioreactor, before active carbon and ozone break down any medication residue.
Rijnstate wants to take it one step further. “Using Wageningen UR’s list of biobased materials we want to try and ferment a much larger part of our hospital waste,” says Koster. The list not only includes familiar disposable items such as coffee cups but also a wide range of sputum pots, syringes, linens, caps, shoe covers and surgical gowns.
At Wageningen UR Food & Biobased Research, scientist Martien van den Oever indicates that not just the bioplastic PHA is eligible for fermentation. “Pads, textile and the mountains of tissues used in hospitals can also probably be fermented in the future,” says Van den Oever. He calculates that 160,000 kilograms of material used at Rijnstate is at least partly fermentable or could be made from a fermentable equivalent. “This would result in biogas that is equivalent to 70,000 litres of diesel or 2.6 terajoules, which is over 700,000 kWh of energy.”
The expansion of the current PHA biobased range with other fermentable materials does, however, require tests to show whether the biobased material is fermentable. “The break-down of PLA, for instance, does not necessarily use the same micro-organisms as those active in the current Pharmafilter process,” Van den Oever explains. Wageningen UR hopes to perform further tests in partnership with Pharmafilter.
Van den Oever makes a clear distinction between four categories. The Wageningen UR research shows that nearly half of the products used are probably already largely fermentable, such as tissues and toilet paper. Additionally, a little under ten per cent – mostly plates, soup bowls and cutlery – is already available in a biobased version but is not being purchased as such. Approximately fifteen per cent, including sheets, bowls, trays and jars currently made from polypropylene, can be made from fermentable materials with minor technical effort should there be sufficient demand. For around 2.5 per cent of the hospital items in Rijnstate, including Velcro, band-aids and suction jars, a biobased version would be a fairly significant challenge, according to the study. The remaining 25 per cent is paper, which is already recyclable.
“This means there are plenty of easy pickings,” says Van den Oever based on the feasibility study. But there are uncertainties as well. “PVC tubes, latex gloves and metal instruments such as scissors, blades and tweezers must be looked at from a new perspective.”
In the coming months, Rijnstate will determine which products can be replaced by fermentable versions and what the financial consequences will be. The follow-up project to the study will look at the possibilities of cooperating with other hospitals to increase the volume and stimulate the market. Koster hopes that decisions will be made in the short term, and that construction will start in late 2016 or early 2017. There are six other hospitals also looking to make the transition towards biobased with biobased materials and the Pharmafilter fermenter. In addition to the hospitals in Delft and Arnhem, these include the Erasmus MC in Rotterdam and the hospital in Terneuzen.
Source: bioplastics MAGZINE, 2015-07-29.