Composting

When green waste is sent to landfill, air cannot get to the organic waste. Therefore as the waste breaks down it creates a harmful greenhouse gas, methane, which damages the Earth's atmosphere.

However, when this same waste is composted above ground, oxygen helps the waste to decompose aerobically which means no methane is produced and after nine to twelve months the broken down waste makes and valuable fertiliser for agricultural and horticultural use.

Schemes for the collection of green garden waste are now common in most European countries typically made up of grass cuttings, pruning and leaves. Currently the UK collects around 2.4 million tonnes of garden waste per year which is being composted and used in various applications every year.

It is also common that garden waste collected and recycled via civic amenity sites. Garden waste is recycled using a simple windrow process and will be composted down into reusable products, the most common being soil conditioner, accounting for 71% of output material. Other outputs are Mulch, Top soil constituent and turf dressing.

It is important that where compost is being produced on a commercial scale that the process is monitored and optimised. By using the Gas Data GFM410 instrument both gases within the pile and its temperature can be measured.

The measurement of the oxygen (O₂) level is critical to be sure the conditions within the pile are aerobic and by confirming that the temperature has remained at sufficiently high level for an extended period of time the end product can be sure to be of high quality and free of unwanted bacteria.