Before the sludge is given to the worms it is mixed with zealite. Zealite is an amazing odour absorbing material. Each molecule has a huge surface area and 'grabs' gases from the material. Material with odour present is detrimental to the worms. Other additives, including green waste, are mixed with the sludge.
Green waste is mulched vegetation and adds oxygen to the mixture, an essential for the worms.
This mixture is spread an inch deep on top of the beds 3-5 times a week. This uses around 300 tonnes of sludge. As well as the worms environmental requirements their food must always be just a little more than enough to keep the beds viable. The worm castings are collected from underneath the raised beds. There are between 150-200 cubic metres harvested per week.