1.1. Recently, rules governing the disposal of waste in landfill sites have been introduced to separate food waste from general waste and from waste to be recycled.

Food waste is a valuable resource in the production of high-quality compost that can be used in gardens and on crops. 

Identify and explain one other advantage and one disadvantage of separating food waste from other waste streams during waste disposal. 

1.2. In-vessel composting (IVC) is an industrial process used to manufacture compost from household food and garden waste. 

Figure 5 shows the typical process flow through an IVC factory manufacturing compost sold in garden centres and DIY stores. 

Figure 5

(i) Suggest the source of the heat referred to in stage 4 of Figure 5.

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(ii) Stages 2 and 3 in Figure 5 are for preparing the biomaterial for the composting stage.

• Mixing involves blending garden waste (grass cuttings, hedge trimmings etc) with food waste (uneaten food, peelings etc.)

• Shredding involves chopping all the pieces down to an average size of 10-15 mm and allowing all the pieces to drop from a height of about 4 metres onto a pile for composting

Suggest how stages 2 and 3 help to increase the rate of decomposition during stage 4.

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1.3. The compost made in Figure 5 is claimed to be 'peat free'.

Explain why it is important for commercially-available composts to be peat-free.