Basics Open windrow
Basics Open windrow composting with aeration from below (@ Agri Service, USA) in their position paper [2]: Only “unavoidable proportions” of biologically degradable plastics may be contained in the biowaste. A targeted addition or admixture of biodegradable plastics to green biowaste must therefore avoided, according to the rules of the DüMV. Screening machine (@ Agri Service, USA) However, Bertram Kehres admits that biowaste collection bags may be useful in helping to collect more – especially wet – kitchen-biowaste. These bags increase the willingness of people to collect biowaste as they help to keep the collections bins clean and reduce odor. But the bags should be marked clearly over their whole surface. BGK is currently undertaking a survey among German industrial composters to collect their experiences with biowaste collection bags. bioplastics MAGAZINE will share the results next year, when published. The VHE demands stricter standards to guarantee the decomposability of bioplastic products during the usual treatment times and to ensure that the quality of the compost can be secured. Open windrow composting @ Agri Service, USA) With view to the next paragraph below, Bertram Kehres told bioplastics MAGAZINE that the attempt of an event organizer to close a contract with a local composter for the composting of certified compostable serviceware was judicially rejected. The court was referring to the abovementioned fertiliser law and the Bioabfallverordnung (BioAbfV; Biowaste ordinance). North America In North America the situation is (almost) completely different. And even across the USA or Canada the situation differs depending on climate, availability of agricultural land (where the compost can be used) and many other factors. One factor is significantly different compared to e.g. Germany. In the US there is a lot of fast food and take-away restaurants, motel-chains, sports arenas and campuses (universities, colleges and – mainly - bigger companies) where food and beverages are served in and/or consumed rom disposable plastic serviceware. On the other hand, there is much more landfilling of waste, including organic waste, compared to Germany. As organic waste can create methane once it reaches deeper layers in the landfill with oxygen missing, there is the desire to divert organic (food) waste from landfills. Now, if all the food waste from the abovementioned locations shall be collected and brought to composting facilities, there is that problem with contamination with the disposable serviceware items. 44 bioplastics MAGAZINE [05/18] Vol. 13
Basics Making all these serviceware items compostable could be solution. So far the theory. However, it is obvious that you cannot replace all disposables by compostable ersions overnight. But there are some solutions to start with. Namely if these closed loop venues like campuses, restaurants or sports arenas convert to (exclusively) certified compostable serviceware, the input into a composting plant can be better controlled and result in significantly lower levels of contamination than what you typically find in residential curbside collection, as Tim Goodman, Cradle-to-Cradle Manager of NatureWorks explained. ONE example is the composting facility of Agri- Service in Oceanside, California (north of San Diego), that bioplastics MAGAZINE visited in mid-September. “There is about one million tonnes of organic waste per year in the San Diego County,” explains Mary Matava, President and Agronomist of Agri-Service. 60 % of that is yard clipping and 40 % food waste. That is 400,000 tonnes of food waste. The capacity of Agri Service with one 75,000 tonnes/a facility in Oceanside and another one further south. We would like to have about 10 % of our final mix be food materials, so our goal is to get 15,000 tonnes of those 400,000 tonnes,” says Mary. “Because we only need a fraction of the total food waste stream we can afford to be choosy”. Agri-Service closes contracts with certain corporate campuses (in their case many are biotec companies), certain music festivals or events such as NatureWorks ITR, where Agri-Service collected all compostable (Ingeo-PLA) coffee pods from the hotel rooms after the conference. “We give our customers training, so that they understand composting, understand BPI (ASTM D6400) certified compostable products and so on”, Mary explains. They know exactly what kind of compostable serviceware will be accepted, and Agri- Service want to approve each item before it is being used. “And even though certified, we test the incoming mixed food waste for its compostability.” And doing so, the composting plant has absolutely no technical problems with serviceware products in their compost. “We manufacture a high quality product and cannot afford to have contamination – and we don’t have any.” Being asked why they only want those 15,000 tonnes and not more, Mary explains: “the market will be saturated with that amount of compost. There is not enough farmland around this area. This is certainly different in other parts of the country. Remains to mention that Mary is proud that the rows in their open windrow composting plant are constantly aerated from below and turned by a big machine once a week. The whole composting process takes 6-8 weeks. “This brings really high-quality compost” Quite similar were the statements of Sergio Gonzalez, Operation Manager at Organix Composting (Hutchins, Texas, USA) who calls the company he works for a hauler, i.e. a company that picks up the food waste from their customers. But Organix also runs a composting facility (open windrow) in Hutchins. Sergio also trains his customers and he checks all incoming organic waste for non-compostable contamination. “If there is such contamination we notify the customer, but there is also a contamination-fee the customer has to pay. After the 30 to 45 day open-windrow composting process the compost is screened with 6-10 mm screens. Any plastic contamination in the compost will show up here and manually be sorted into obviously compostable material that goes back to the start of the process and a fraction that will be finally disposed to landfill. A further step might be collecting food waste from the many fast food and take-away restaurants and motels. But this is completely in the hand of franchisers who own the waste after picking it up. And they dispose of it, where it is cheapest – landfill. To discuss all details of this complex situation would go beyond the scope of this article. Another step further would be the composting of postconsumer organic food waste from curbside collection. This, however, is still some time off in the future for Mary and many other US-composters who choose to focus on closed-loop venues and commercial generators, first. Totally different as in Germany. However, as Rhodes Yepsen, Executive Director of BPI (the Biodegradable Products Institute) explained during his presentation at ITR (cf. p. 16), there are over 300 communities in the USA that collect curbside residential food waste, representing about 5 million households. About 40 % of those programs allow compostable foodservice items. bioplastics MAGAZINE will try to get in touch with some of these soon. So please – stay tuned. [1] Kehres, B.: Kompostierung von ‚Biokunststoffen‘ ist ein Irrweg (German language only); tinyurl.com/bgk-position [2] N.N.: Position zur Verwertung von biologisch abbaubaren Werkstoffen (BAW) einschließlich BAW-Sammeltüten über die Biotonne (German language only) tinyurl.com/vhe-position bioplastics MAGAZINE [05/18] Vol. 13 45
