Friday, December 11, 2009

Municipal Composting

What is Composting?


Composting is the natural process of biodegration under controlled conditions. Various microorganisms such as fungi and bacteria digest and/or break down organic matter into dark coloured humus (soil) often refered to as compost.

What Can be Composted?


All organic items can be composted, i.e. anything that rots. This list includes plant vegetation, food scraps, paper products and pet waste. An important note with composting however is that the material that is composted can have an effect on the final soil product. Chemicals in or on composted materials, which cannot be broken down, will taint the final compost and if toxic can transfer that toxicity to the plants grown in the soil. For compost being used to grow vegetables, there should be more discretion used in selecting which materials are composted. Dog poop in biodegradable bags is not suggested for use in compost that will eventually be used to grow food since its possible that some parasites a dog could have may be transfered to the food and therefore to whomever consumes it. One thing that is important to note is that many of the products today that claim to be biodegradable are not actually (see Bio Plastic Info). One of the products that claim to be biodegradable but are not are anything containing the letters OXO. These products typically require sunlight to properly degrade and do not use bacteria to break down the material so it is unnecessary to compost them anyways. Because of these reasons, OXO products are not suitable candidates for composting and will leave pieces of plastic in your compost if they do make it in.

How do City Compost Programs Work?


Since city composting programs are a relatively new concept, there are few if any standards that are shared between them all. It's important to find out what standards your region uses since different regions will accept different materials. Some will accept the materials in plastic bags since they break the bags and empty the contents into the composting facility (as the Guelph-wellington facility used to). The one standard that's becoming more and more recognized for compost bin liners is the BPI compostable certification which runs on the ASTM D6400 standards. This standard requires the bag to biodegrade beyond recognition within 90 days.

Why Compost?


There are many reasons why composting in important and beneficial to all. It's becoming clearer every day that if we want to sustain the earth as a habitable ecosystem for humans, plants and animals then we as humans must and have a responsibility to reduce our waste and help save the environment that we damage every day. Another reason why people compost is the rewarding feeling they get from creating something and if they use it to garden with afterwards it adds to their appreciation of all that is grown. It is also beneficial to your garden to use compost since it will be some of the richest soil you can find or buy providing tons of nutrients for growing plants.

How Long Does Composting Take?


Typical composting takes around 3 months to completely break down the components and make it suitable for use as soil. Many city composting facilities require the material they take in to be biodegradable within one month so it's important to check the requirements of your regions composting facility. Some materials take longer than others to compost and there are many factors that effect composting rates such as aeration, heat, bacteria levels, etc. As a result of all these variables it is virtually impossible to give a definite amount of time an item will take to biodegrade.