4. Conclusions
This review has identified alternate methods of handling and processing hatchery waste that could be utilised.
Hatchery waste can be separated into solid waste and liquid waste by centrifuging
Alternatively inclined screens and the use of a belt or filter press can separate the components of the waste
Flexible multi-layer filters can be used to separate liquid wastes from solid wastes
Another system for separating liquid and solid waste is to use a conveyor with an upper and lower conveyor roller. Liquid and solid wastes are separated and placed in collectors which are located near the upper and lower rollers
Shells can be separated from the hatchery waste as follows;
A powerful suction vacuum is used to only remove the dry, very light shells from the hatchery waste leaving the heavier infertile eggs
Eggshell waste can be separated by using a vibrating or shaking device and a cyclone forced-air separator to further separate lighter materials from heavier materials in hatchery waste
Alternatively live chicks and unhatched chicks or clear eggs from the hatching tray are placed on a moving belt with fixed gaps that only allow chicks to slide through, while shells and unhatched eggs are retained on the belt while dead embryos are disposed into a separate container
Products that can be developed from shell include;
increase the mineral content of compost
spread around plants to deter slugs and snails
mixed with garden soil for use as a fertiliser
mixed with seeds for use as a feed for aviary birds
added to cement to increase its strength
used by artists to make mosaics
to make textured paint for 3D effects in artwork
produce collagen from the egg shell membrane.
Methods which can be used for treating the solid waste include the following;
Use of a furnace to heat the waste to produce steam to run a turbine generator and produce electricity
Rendered, autoclaved, extruded, boiled, ensiled, enzyme treated to produce pet or livestock feed or composted to produce fertiliser
On site stabilisation of product by using an in-line composter.