Waste disposal and treatment can be costly for foundries so it makes good sense to have a closer look at the materials, processes and equipment you use to see where you may be able to save dollars.
Some ideas on how foundries can reduce waste
Implement better housekeeping procedures by keeping storage and work areas clean, organised and labelled.
- Regularly review your inventory and stock management procedures. This may help you identify any materials you are over-using, whether new materials delivered are in acceptable condition, and the batches of materials that need to be used next.
- Drums and chemical containers take up space in your skip bin. As they are currently unrecyclable you should either reuse them or return them to your suppliers. Most suppliers will collect, wash and refill drums. If your supplier will not collect them there are others that will.
Foundry finds use for waste sand
A small non-ferrous foundry operating for 35 years in Sydney has six employees and manufactures aluminium and copper base castings.
This foundry was considering closing down and redeveloping the site. The cost of an environmental impact study required by the council was prohibitive so the owners decided to continue with the foundry business and adopt environmental improvements.
The following environmental improvements have been made:
- Storage of used moulding sand is separated from metal and other refuse and
stored in a covered concrete lined bunded area for removal and disposal. Previously all waste was mixed together and thrown into a skip bin for disposal.
- After testing of the used foundry sand was carried out and it was classified as inert waste the business found an alternative to disposal. A construction company took the sand and used it as fill for drainage pipe channels on a construction site.
- Gutters, downpipes and drains were inspected and repairs made to ensure that rainwater runoff does not pick up contamination.
Reuse of foundry sand
Sand is one of the major wastes in ferrous foundries. Some larger foundries have sand reclamation units which partially reclaim sand for subsequent use.
Used foundry sand can be reused in various applications as an alternative to sending it to landfill, and reuse options are well established in England, Europe and North America. Reuse options include cement manufacture, asphalt, concrete, bricks and free-flow fill for certain construction applications.
Case studies show that it is not only better for the environment but is profitable for the foundry to sell the sand to an alternative user. These foundries have significantly reduced the volume of waste sand going to landfill and actually offset the total cost of transporting the sand 'in' and 'out'.
Waste sand classification
Waste foundry sand should be tested according to the DECC's Environmental Guidelines: Assessment, Classification & Management of Liquid & Non-Liquid Wastes and according to Australian Standard AS-1141: Methods for Sampling and Testing Aggregates, to determine if the waste classifies as inert, solid, industrial or hazardous.
Handling wastes on site
If wastes are kept on site they should be classified, labelled and packaged properly and then stored securely (e.g. in a roofed area that rainwater cannot enter.) Any stored wastes that find their way into the stormwater system (especially during rain) could cause pollution, and could result in a fine.
Remember, you are responsible for your waste and for ensuring that it is disposed of correctly, even after a contractor has picked it up. Because of this ongoing responsibility you should maintain a record of what you have disposed of.
- If liquid waste is stored on-site it should be labelled and packaged properly and then stored securely (e.g. in a roofed and bunded area where rainwater cannot enter).
- Remember, if you are a generator of hazardous waste you are responsible for classifying it and ensuring that it is transported to a facility that is licensed to receive and/or treat that type of waste. Your waste contractor should be able to provide advice on these issues.
- Tipping liquid waste into the soil on your property is illegal. Heavy fines can be issued as well as a notice to clean up the contaminated land (a very costly
- Hazardous waste requires special attention for safe and proper disposal. Ask your local council, DECC Environment Line or specialist waste contractor for disposal requirements for these wastes.
Foundry separates, recycles and reduces wastes
A small cast iron foundry with 12 employees has operated for 50 years in the southern Sydney region. It has recently developed an environmental awareness and safety policy.
The following environmental improvements have been made:
- Raw materials are purchased from suppliers who only supply clean scrap metal with no oil, dirt or grease contamination.
- Raw materials such as pig iron and steel scrap are held in separate holding bays. This material is transported in steel bins by forklift to the furnace for melting. This has reduced metal scraps being scattered in the premises.
- Liquid chemicals supplied in drums with outlet taps have collection trays placed to collect any drips. Any collected liquids are reused.
- Resin is stored in returnable containers to avoid accumulating empty drums which have to be disposed of. The supplier exchanges an empty container with a full one on delivery. A portable one-tonne capacity steel bund has been built to WorkCover requirements, to hold liquid resin binder.
- Sand disposal costs for the foundry have been increasing. A test report on the sand classified it as inert, reducing disposal costs substantially.
- Housekeeping practices have improved, with separate bins for different wastes.
- Employees are informed of their environmental responsibilities and encouraged to be environmentally aware.
- Downpipes and stormwater drains are inspected to make sure there is no contaminated runoff.
- DECC Environment Line, Tel: 131 555
- Your local council
Page last updated: 27 February 2011