Trains in developed countries started to change over from dropping it on the track in about the 1980s, anything from before that time is likely to still do this, it is often impractical to convert them.

Apart from the jokes about those fishing under the bridge, it does tend to get strewn across the underside of the car over time and is a distinct hazard to maintenance workers who go underneath there to do jobs like change the brakes. It also causes issues with air-conditioning intakes. Put them up high and you get diesel exhaust fumes drawn in; put them down low and you can get a different contaminant. The diesel Inter-City 125 trains which came into use in Britain in the 1970s, and are still very much in use, have a notable smell drawn in to the air-conditioning when making heavy braking. This is the source.

Just tip the flush button and then everything is gone !!! Very easy :)

For "boats" (ships?) their are specific International rules about dumping "solid" and "liquid" wastes...:)

I can't remember the distance involved (and it may have changed more recently anyway) but once a vessel was "X" miles from land "direct overboard gravity discharge" was a legal disposal method...

The (war)ships I served on ALL had primary (maceration/aeration) and secondary sewage treatment plants....

As with trains... the equipment fitted to ships would vary with age/location...

After reading this thread I think I'll confine my in-flight consumption to.... I dunno... whiskey? :D

Doesn't matter how small the boat is, it is illegal to dump human waste closer than 3 miles off-shore. Law Enforcement is able to board your boat to inspect if you are in compliance.

That doesn't mean it doesn't happen. Upgraded boats often retain the old egress system also, and have a manual valve for switching when inside/outside the legal limit. However, since there is a cost to pumping out the holding tank, shall we say that the Charts/Loran/GPS is often not closely scrutinized before doing the deed? However, the vast majority of those captains will also want the first one to indeed go into the holding tank, as a "token dump", so there is "proof" to boarding inspectors that they did retain waste in the tank when within the 3-mile limit.

Steve

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I saw a tv special on the A380 recently, and they had a few minutes on the toilet systems, mocked up for testing in a German engineering location. It was pretty neat -- their system was a frame scaffolding the full size of the A380 (cabin area) with the exact pipes laid out (but made out of transparent plastic instead of the lightweight titanium on the real plane).

They showed the flushing of water and toilet paper, and said that the stuff travels at 90 mph through the tubes. It looked pretty instantaneous from the bowl to the transparent holding tank. The paper looked pulverized in the tank.

The most interesting thing was that the bathroom near the pilots up front actually has to empty all the way to the back of the plane. That's some suction.

Do the toilets work when the airplane is unpressurized waiting at a gate? There is no vacuum overboard...

So, was there ever a period of time in the early history of commercial aviation that was, say, between the time that longer range commercial aircraft where introduced, and the time that holding tanks were introduced?

BTW quite some time back I spent a bit of time on a dive shop that was offshore on an anchored, floating pier. There was no restroom there or anywhere convenient. I noted that many of the employees used to like to take a break every now and then, and go take a good brisk swim for a few moments. It was a dive shop after all. Coincidence? You decide. I never ask.

I knew I was forgetting something!! Thank you! :D

I believe it's pretty clearly laid out in this thread that the toilet vacuum system doesn't work via the pressure difference between the pressurized cabin and the outside high altitude. Thus, if the plane has power at the gate or is running it's auxilliary power unit, or running on batteries, the toilets will work waiting at a gate.

I was perhaps being a bit simplistic...... First, what you are stating is related to the US, and many other countries don't follow the same standards.

However, even within the US it can get complicated.... There are systems that "chop" up the waste and add chemicals to, um, "clean" up the waste somewhat (MSD Type I and II, aka "treated waste"). There are some areas of the US classified as "no discharge zones (NDZ)" that prohibit any dumping, such as the Florida Keys, The Hudson River, The Great Lakes. and parts of New England. Those areas require the ability to switch to a full holding tank. However, while in international waters, it's fish food.

Lets just say that many of my trips were in the Caribean, who are not as careful regarding waste disposal....