Plastics compostability

Paper is a biodegradable alternative to plastics. Compost bags made of paper are rather heavy. Pure Kraft paper exhibits a limited resistance to oil and fat, and the rough surface limits the printability. But, the acceptance by customers is high because paper is perceived as an enviromnentally friendly material. 

Degradable Additives for Plastic Compost Bags, BioCycle, March 1995, pp. 77-78. 

Cnd-of-life options for plastics are important factors that influence the life cycle assessment (LCA) of plastics. Disposal options for plastics are to mechanically recycle the plastic, chemically recycle the plastic, compost the biobased plastic, burn the plastic into energy, or bury the plastic in a landfill. 

Industrial compost is a viable end-of-life option for compostable plastics but not traditional plastics. Compostable plastics biodegrade under industrial composting conditions (Greene 2007b Greene 2008 Greene 2009). 

Chaffe, C. and Yaros, B. (2007) Life Cycle Assessment for Three Types of Grocery Bags - Recyclable Plastic Compostable, Biodegradable Plastic and Recycled,... 

For water-soluble polymers, there is a weU-estabUshed disposal infrastmcture, with the widely available wastewater treatment plants, whereas plastics being developed for composting require large-scale implementation of a composting infrastmcture. This fact will certainly influence the rate of their acceptance. 

There have been numerous communications on the subject of biodegradation test methods, including aerobic compost (30), anaerobic bioreactor (31), general methodology and future directions (32—34), and a fine review article (24). ASTM (22) and MITI (35) have also set forth standard testing protocols for plastics, as shown in Table 2, whereas OECD test methods (29) are more suited to water-soluble polymers. 

The Commission is working on establishing end-of-waste criteria for a number of specific recyclable materials including metal scrap of copper, aluminum and iron, waste paper, waste glass, compost, and plastics. Based on the results of two frontrunner studies, ferrous scrap and aluminum scrap in 2010, the first... 

Table 2 presents the results of tests to measure the calorific power, ash content, and chlorides concentration of some of the materials obtained from the separation process, such as polystyrene, aluminum foil, plastic foam, and other plastics (general, clear, colored, black, and vinyl). Polystyrene and clear plastic have very high calorific power and low levels of chlorides, but polystyrene has very high ash content. Figures 10-17 present the samples of waste components from the separation and composting plant of Cantagalo. 

Fig. 12 Sample of plastic foam from Cantagalo Waste Separation and Composting Center...

Most of the plastics and synthetic polymers that are used worldwide are produced from petrochemicals. Replacing petroleum-based feedstocks with materials derived from renewable resources is an attractive prospect for manufacturers of polymers and plastics, since the production of such polymers does not depend on the limited supply of fossil fuels [16]. Furthermore, synthetic materials are very persistent in the environment long after their intended use, and as a result their total volume in landfills is giving rise to serious waste management problems. In 1992,20% of the volume and 8% of the weight of landfills in the US were plastic materials, while the annual disposal of plastics both in the US and EC has risen to over 10 million tons [17]. Because of the biodegradability of PHAs, they would be mostly composted and as such would be very valuable in reducing the amount of plastic waste. 

Self-heating is quite common, yet it receives attention only when it causes economic losses or leads to fires. Fresh grass clippings in garbage cans and plastic bags heat within an hour or so. Piles of manure and compost always seem to self-heat, as the steam rising from opened piles indicates. Farmers have cause to be alarmed when temperatures rise in hay, silage, straw, cotton,... 

Narayan R (2001) Drivers for biodegradable/compostable plastics and role of composting in waste management and sustainable agriculture. Bioprocess Solid Waste Sludge 1(1)... 

These results suggest that pure aromatic polyesters may function like the long-lived components in humus and may provide useful properties as a soil additive. Grass sod growing studies using municipal-waste-derived compost in combination with chopped plastic fibers demonstrated improved growing rate and root structure development to accelerate sod production. 

Once you have started making compost, you may find that you need two or more containers, although it is possible to get by with just one. Once it is maturing, compost can be turned out in a pile and covered with a plastic sheet, freeing up the bin that it was in. 

Recycled plastic containers are compact they may have a door at ground level to access the finished compost, but usually have no base you simply lift them off the ground. 

Keep it warm. The bottom layers of a pile are usually the first to decompose, generating heat that will rise through the pile and be lost from an unlidded bin or uncovered pile. The heat is valuable to the composting process, so use the lid, or cover the heap to keep it in. A cover will also conserve moisture, while keeping out the rain. You can add extra insulation by making a compost "comforter"—a thick plastic sack filled with fallen leaves. 

Red wigglers, also called brandling worms or manure worms, are the type most commonly used. They are very efficient recyclers of organic waste and will reproduce quickly in the confines of the bin. It is a good idea to start a worm bin with at least 1,000 worms—about 18 oz (500 g) in weight. They can be extracted from a maturing compost pile, a manure stack, or another worm bin, or they can be purchased by mail order or over the Internet. The dark, moist conditions that worms need to live in can be provided by keeping them in a plastic bin or a wooden box of some form. 

Vegetable waste has a very high moisture content Liquid will tend to accumulate in plastic worm bins, and the worms may drown unless adequate drainage is provided. If there is a reservoir at the bottom of the bin, the liquid can be drained off through a spigot This liquid contains some plant foods, which can be recycled by watering it onto the compost pile. 

Always use natural fibers such as twine and raffia for tying up plants. They are less likely to strangle a plant than plastic or wire, and can safely be composted. To avoid eye injuries, top canes with purchased, or homemade, cane-toppers. 

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