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Dishwasher or plastic?

oldunbeliever

Student
Joined
Mar 9, 2003
Messages
28
The automated forum host keeps nagging me to post something, so here goes. Fire away.

It involves an interesting little puzzle I thought you guys might like to take a stab at.

The other day our local television station in one of those promotions designed to show how "green" the station is, displayed a list of "green options". One of them was "skip the paper plates and use real plates at your the next party."

I got to thinking about this. Yeah, I know, that's how you get in trouble. Too much thinking. But anyway, I thought about it and came up with this question (don't know if it's been answered here before but if so I havent seen it and I've been lurking here -- and, yes, automaton, actually posting occasionally -- for several years): Anyway, let's say we have a party for, oh, 25 to 30 people. We use plastic plates and glasses and plastic knives and forks. At the end of the party we have a two or three large bags of trash which end up eventually in a landfill where the plastic doesn't bio-degrade for a few hundred years. Agreed. That's not good.

So, OTOH, lets say we skip the plastic and use real plates and silver. The stuff has to be washed. Say three of four dishwasher loads of stuff. Maybe more. Each load uses several gallons -- maybe a lot more, I dont know -- of valuable water. The water has to be heated, whatever energy that takes, and the dirty water, full of detergent, is flushed into the sewage system where it may or may not decompose in a couple of lifetimes.

Which is worse? I really dont know, and hope somebody here does. But I am inclined to think that maybe the 3 or 4 bags of trash in the landfill are actually less environmentally damaging than the gallons of water used, the energy used to heat it, and the effluent it dumps into the ecosystem.

What say ye?
 
It might depend on the dishwasher, and where it is used. You don't have to use that much heat, if you have a well and a septic system, there's no real environmental problem, just water up and water back down.
 
What about biodegradable, unbleached paper plates? If you are lucky enough to have a nice compost heap to dump them on, that's a little bit greener. Or what if you don't use the dishwasher? Washing dishes in the sink never hurt anyone. Also newer dishwashers use less energy and less water than old ones. And they make biodegradable detergents. And if you have a greywater system set up, again that's usable water for toilets and watering plants.
I think it's a false dichotomy. There is always another way, another solution, another perspective.
 
Both the paper plates and plastic cultery, and the "real" dishes have a manufacturing and transport cost from an environmental perpective.

"Real" dishes last a long time, on the other hand, and so over their lifetime I would expect this cost to be minimal in comparison to that of the water used in the washings. But this might change from region to region as in some places fresh water resources are in much lower supply.

I'm not sure how plastic is made, but the paper plates will require wood, I think quite a bit of water, and power to make. Burning of fossil fuels for transport. That needs to be accounted for.

Then again, how many can be made for a given amount of wood, coal (oil, or natural gas), water, etc.? It's possible that they are so cheaply made that this cost is very minimal, but I wouldn't expect that offhand.

All good questions.

As for myself, I don't have a dishwasher, and when I wash dishes I turn off the water when it's not dirrectly striking the dish. A pretty small amount of water is being used there, and depending upon how dirty my dishes are or what they had on them, I often wash with cold water.
 
One useful rule of thumb in such cases is to compare the actual costs to you, as in how much money you pay, for the two options. This isn't totally reliable but the cost of the product generally reflects the resources used to manufacture and transport it. Ten or fifteen dollars' (retail) worth of disposable plasticware (which includes markups that don't reflect environmental costs, but doesn't cover disposal costs, so those two errors partly cancel out) > the energy, water, and wastewater treatment costs of three dishwasher loads at about a dollar per.

Respectfully,
Myriad
 
If you count all the costs, both monetary and environmental, I think you'll find a dishwasher is very cheap to run compared to buying plastic. I did a rough calculation for my dishwasher, etc. here in a rural setting, and it takes a bit of rounding up to arrive at an energy cost of about a nickel a load if you turn off the heater, and with well and septic there's almost no environmental impact. The detergent is probably the biggest expense.

But most of us do not have enough china or silverware for a party of 25 or 30, and few of us would want to have to wash that much stuff after a party anyway. For that, I'd get plastic and to hell with the theoretical economy.
 
Do you guys really have parties with 25-30 people at your house?

I seldom invite more than 5-10 people over, and when I do have more than 10 I just ask one or two friends to bring some dishes with them.
My place is pretty big, but more than 10-12 people and it's far too crowded.

Maybe that's because I don't have that many chairs, though.

Oh, sorry for the derail.
 
If you count all the costs, both monetary and environmental, I think you'll find a dishwasher is very cheap to run compared to buying plastic.
I don't know where you found yours, but mine costs me a fortune for maintenance and operations but still won't even walk at a brisk pace. Still, even without considering batteries and inflation she's much better than the plastic alternatives. :D

Anyway, let's say we have a party for, oh, 25 to 30 people. At the end of the party we have a two or three large bags of trash which end up eventually in a landfill where the plastic doesn't bio-degrade for a few hundred years.
Also, aside from questionable landscaping benefits, that's the end of the return on all the resources invested in those utensils manufacture and transport.
So, OTOH, lets say we skip the plastic and use real plates and silver. The stuff has to be washed. Say three of four dishwasher loads of stuff. Maybe more. Each load uses several gallons -- maybe a lot more, I dont know -- of valuable water.
Water isn't particularly valuable, and besides it's not really being "consumed" unless you "irrevocably" poison it or pump it inaccessibly underground -- the hydrologic equivalent of a landfill. What's really being consumed is the rate of supply of clean potable water, which in many circumstances may be more precious.
The water has to be heated, whatever energy that takes, and the dirty water, full of detergent, is flushed into the sewage system where it may or may not decompose in a couple of lifetimes.
Heated water isn't as necessary to dishwashing as many people believe; it's mainly a convenience/performance factor for typical automatic dishwashers and subsequent sanitation. Ditto detergent; you need some to deal with lipids ("grease"), but most people and dishwashers use more for convenience and performance.

The dirty water from dishwashing is "gray" water; it's not clean enough to be potable for drinking or further dishwashing, but neither is it so full of pathogens and filth as "black" water from toilets and the like. It doesn't have to be flushed into the sanitary seage system -- again, that's just a convenience we're arguably abusing.

I don't know how wastewater is handled in your part of the world, but most places in the developed world treat it to various degrees and return it back for the world's glorious hydrologic cycle to return as clean as it was before it was collected for treatment and use as potable water. Sure, the level of environmental impact depends strongly on the details of that treatment and disposal, but those can be made fairly benign. That may not help you much if you're in an arid region, and we could frankly do with less of it around here, but in the big picture that water's hardly lost to future use.

Instead of chunking directly into a dishwasher you could always scrape most of the gunk into your compost heap, wash the dishes in unheated water, and subsequently use much less energy for sanitization (e.g. a smaller amount of hot water, chemically [with variable environmental impact], via waste heat from baking operations, radiologically, yada yada...). Instead of dumping the washwater down the drain, use it for irrigation; the water will be pristine after evaporation or tranpiration from the plants, which will eat the organic and phosphate pollutants if an appropriate "detergent" was used. That's less convenient, of course. What's more important?
Which is worse? I really dont know, and hope somebody here does. But I am inclined to think that maybe the 3 or 4 bags of trash in the landfill are actually less environmentally damaging than the gallons of water used, the energy used to heat it, and the effluent it dumps into the ecosystem.

What say ye?
I'm inclined to believe that washing and reusing utensils, even by common and convenient means, is the generally the more environmentally friendly option from a global perspective. More locally, your mileage may vary depending on local access to water supply and landfill space resources.
 
One useful rule of thumb in such cases is to compare the actual costs to you, as in how much money you pay, for the two options. This isn't totally reliable but the cost of the product generally reflects the resources used to manufacture and transport it.
I suggest that disposal costs are rarely reflected in how much money you pay. Even if those costs are monetary (e.g. charges for refuse collection and sewage disposal) allocation is often difficult.

Still, I concur that even direct monetary cost is a useful first approximation for comparing overall resource consumption of your options..
 
Thanks for all the answers. All good ones, as I expected they would be. (Well, except that one. He/she seems to have issues.) I particularly like Noblecaboose's. There are always other solutions. The TV promo was simplistic. As, perhaps,was I. Thanks again.
 
I like Noblecaboose's as well, but sadly she's a happily married woman now.

The Eden Project in Cornwall used to use biodegradable, disposable wooden cutlery and paper plates in its restaurants. The cutlery came in a thin sheet of wood that you punched the knife, fork and spoon out of. It was pretty nifty. However, they have since had a rethink and concluded that biodegradable or no, they were still having to ship nine tonnes of waste a year out to the landfill sites. So they've moved to using washable plates and cutlery. This has had a net effect of reducing transport and energy costs, which they regard as a substantial environmental gain and gives them estimated financial savings of £180,000 over five years to boot. Plus it's created two new jobs at the dishwasher station!

So I'm going to copy their answer and say "Wash 'em!"
 
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...I'm not sure how plastic is made, but the paper plates will require wood, I think quite a bit of water, and power to make...
Plastics are presently made from petrochemicals, that stuff that soon will be over $100 a barrel and is non-renewable, unlike wood. But both could be recycled. I don't know about the energy costs involved.
 
If the floor and fingers were good enough for my ancestors, they're good enough for me. Just let the dogs eat the leftovers and have your vassals scrape out the dirty straw every few weeks.
 
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