Our Biomass-Cycle

What

We collect and conserve our organic kitchen waste and thus kill two birds with one stone: we reduce the amount of our residual waste and instead use these precious raw materials in order to generate valuable substrate/fertile soil from them again – through fermenting them first and composting them afterwards.

Why

To ensure the best quality of compost here at Hochschule Geisenheim University we practice guided aerobic composting. With this method a compost heap takes up to 12 weeks from setting up to completion of the conversion (depending for example on the weather). For setting up a new compost heap we need a certain ratio of nitrogen heavy to carbon heavy materials in order to provoke the processes we need. While carbon heavy materials (e.g. branches when trees are cut) tend to come together in larger quantities at a time and also keep very well for a long time even when exposed to oxygen and higher temperature (like laying around outside in the summer), nitrogen heavy materials (e.g. fresh, leafy greens, veggies and what’s left of them when cooking) only accrue in smaller amounts at a time and then they really don’t keep very well at all especially when exposed to oxygen and higher temperature (like laying around outside in the summer – as you might know from at home). Therefore it makes sense to preserve the kitchen waste as an intermediate step – which we do very energy efficient by fermentation (bokashi) – and then set up a new compost heap only when we have enough of every ingredient we need. Using what we have ourselves right here – instead of paying first for getting rid of our precious kitchen waste (which might then just be burnt) and then having to buy back pretty much the same kind of stuff for making our compost.

How

1. We provide each institute and department with
   • 2 kitchen waste buckets (with a lid) and
   • manual: “Kitchen waste collection”
   • manual: “What goes where and why”
2. Please place bucket #1 in an easily accessible, cool place at your workplace (e.g. in the kitchen, near the coffee machine).
3. Please collect your organic waste in the bucket,
   • everything that accumulates when preparing food at your workplace,
   • rule of thumb: everything that you would throw on a compost heap is fine in the kitchen waste bin,
   • but even larger quantities of orange peel, for example, are no problem thanks to fermentation (more on this in the instructions).
4. Please bring the bucket in use to our exchange station twice a week:
   • every Tuesday AND Friday
   • BEFORE 13:30
   • at the west entrance of the southern connector oft he greenhouses (soil science institute)
   • exchange it for your other bucket (rinsed bucket #2) – and proceed with it the same way.
5. We will register your recyclables for you and process them (first to bokashi, and then to compost), and also rinse your bucket for you.

Would you like to help us reduce the amount of residual waste at HGU and join in in recycling our precious organic waste materials in a meaningful way?
Do you have further questions about the process?
Please email us at nachhaltigkeit(at)hs-gm.de with the subject line “Question about kitchen waste/Bokashi”.

As part of the “PC4Compensation” research project, the volume of soft biomass was investigated at our university. This had previously been disposed of for a fee, so we had to come up with our own system and established guided aerobic heap-composting. As kitchen waste is very suitable for this, but is produced continuously but only in relatively small quantities and then very prone to spoiling, it was necessary to preserve it for the setup of the respectively next compost heap – the idea of bokashi production was born.
Now our valuable organic material is fermented using Effective Microorganisms and thus biologically stabilized until it is further used in composting.

2020/2021

the Department of Applied Ecology collected a total of over 300 kg of kitchen and coffee waste from four institute kitchens on the West Campus. This made it possible to recycle almost 9 kg of material per person per year, which would otherwise have ended up as residual waste.

The finished compost was used for experiments and on the institutes' grounds.

2022

the project ended and with it the kitchen waste collection. Since the winter semester 2022/2023 students have the opportunity to learn guided aerobic composting for themselves now as part of the QSL project “Sustainable waste management” (since 2023 also using the HGU Bokashi again).

2023

Now part of the Department for Strategic University Development and Sustainability, we resumed this campaign – also due to the positive response from the college – now with more staff and with all interested institutes and departments involved. Due to the increased volume, the pick-up system became a drop-off system (for example as a short digestive walk after lunch). Within 7 months, almost 500 kg of kitchen scraps were collected in this second round, which we turned into valuable compost instead of it ending up unused in the residual waste.

The finished compost was again used for experiments and on the areas of the institutes, and this time also by the neighboring LLH and to a small extent privately by students for the community garden and by employees of our university.

2024 – until now

Once again, we have made the process a little more efficient and started the next round in the early summer – now supported by student assistants.

Are you interested in using our compost in your own garden?
Please email us at nachhaltigkeit(at)hs-gm.de with the subject “Interested in compost”.

Due to construction at the administration building until further notice you will find us here:

Industriestraße 2 (Building 9002)
2nd floor, to the right/north
65366 Geisenheim