Segregating alternative-process waste

Purpose

To end an alternative-process session with every stream in a container that says what is in it, and with the two streams that must never meet standing apart from each other.

When to use it

Every session in Parts XXI to XXV, from before the first tray is filled. A container fetched after a bath is spent is a container that gets filled with the wrong thing.

The domestic silver rules do not change here and are not restated: silver-bearing waste and general chemical waste still govern their own streams.

Before you start

You should already have read the disposal caveat and looked up what your own authority accepts. The chemistry below does not change with where you are; the lawful route does, it differs between neighbouring authorities, and it changes. Check your local regulations; they govern.

Level A as a routing procedure, run inside sessions at their own levels. The gloves and eye protection of the session stay on until the last container is capped.

The rule that shapes the bench: the ferricyanide or thiocyanate container and any acid container are an incompatible pair, and the acid exclusion rule is where that is set out. They do not stand beside each other and they never share a funnel.

Procedure

Before the session

1. Decide the streams your session will actually make, and write the list down. Most alternative-process evenings make five: iron and hexacyanoferrate; silver-bearing; noble-metal; clearing baths and their rinses; and wash water.
2. Label a container for each, in words, by the labelling procedure, and give each its own funnel in the process’s own colour.
3. Stand them apart, with the ferricyanide or thiocyanate container at the far end from anything acidic, and all of them within reach of the sink.
4. Open every container before the first pour. A capped container gets skipped.

During and after

5. Put the coating residue, the cup, the blot and the rinse off the rod or brush into the stream of the sensitiser, not into the wash stream. It is the smallest volume and the highest concentration.
6. Put the first bath and the wash water of a cyanotype into the iron and hexacyanoferrate container, including the blue clouding off the sheet, which is image substance rather than dye.
7. Put the first wash of a printing-out silver sheet into the silver container. It is the most concentrated silver solution this course produces.
8. Put a spent gold or platinum-group toner into the noble-metal container, which is the one worth recovering, and never into a container that has held an acid.
9. Put spent thiosulfate fixer into the silver container, separately from the first wash but in the same stream, and do not top a silver nitrate rinse into it casually: the two throw down a black sludge.
10. Put the clearing baths and their half-minute rinses into their own container. They carry iron and whatever metal washed off the sheet.
11. Put a residual-iron spot test’s dish, pipette and waste into the hexacyanoferrate container and nothing else, from a station that stands apart from every acid bath.
12. Collect the wash water rather than draining it, and say on its label what it is the tail of.
13. Bag the solids separately — blotting paper, trimmings, spoiled sheets, gloves, wipes — and seal the bag rather than leaving it open.
14. Cap each container, wipe its outside, update its running-volume line and add the date.
15. Rinse each funnel into its own container and hang it with that container’s set.
16. Take each container by the route you checked and dated, and record the date you last checked it.

How you know it worked

• Every container was labelled and open before the first pour, not after the first spill.
• The hexacyanoferrate or thiocyanate container stands away from every acid, and no funnel crossed.
• The first wash of a printing-out sheet went to silver and not to the wash stream.
• The noble-metal container holds the toner and the clearing baths that carried metal, and is capped.
• No solid was left drying in an open bin.
• Each label carries contents in words, a running volume, a route and the date the route was checked.

If a step fails

Step 1, a session made a stream you had not planned for. Stop and label a container for it now, in words, before you pour. An unplanned stream poured into a planned container is how a container becomes unknown.

Step 3, there is not enough bench to stand them apart. Then stand the acid container outside the room, which is the arrangement the acid rule prefers anyway, and bring it back after the session.

Step 5, the coating residue went down the sink. Record the volume and move the container before the next session. The entry is what changes the habit; the container’s position is what makes the habit possible.

Step 8, the only container free has held an acid. Do not use it. This is the exact case that the unlabelled container procedure exists for, and the answer is another container rather than a rinse.

Step 11, spot-test waste has gone into the clearing-bath container. The clearing baths are acidic. Do not cap it, do not move it, leave the room and ventilate from outside; thereafter it is an unknown and it is routed as one.

Step 14, a container is full mid-session. Cap it, date it, start another. Never decant it into an unlabelled bottle to make room: that turns an identified, recoverable waste into an unknown one.

Step 16, your authority does not accept a stream. It stays capped, labelled and in its tray while you find one that does.

What to record

One line per container: date opened, stream in words, container and size, date closed, running volume, route and the date you checked that route. Then two columns the ordinary waste log does not need — which process the stream came from, and which metal it carries — because those are the numbers a recovery decision is made from, and nobody can reconstruct them later from a bottle of grey liquid.