plating, anodizing, & finishing Q&As since 1989
Hazards presented by wastewater streams
I am marie d., 10 yrs. old and was given by my elementary school teacher assignment regarding electroplating. I read your "plating shops for the 90's and beyond." if I understood it right, it's more of creating shops, modern ones that shall avoid mistakes that gave damages in the past. I'm interested in the flaws observed before.
1. could you please characterize the hazards presented by wastewater streams generated by electroplating.
2. what are the sources of wastewater for the electroplating industry.
3. the process of electroplating before and now.
thanks and regards,marie
- cebu, philippines
Your questions and comments would require a very long reply and would be filled with a great many terms that are not understood, or worse, misunderstood. The subject that your teacher has given you would be difficult for a senior to do a good job on because of its depth and because there is great differences of opinions, all backed by their version of scientific data.
Platers are currently very strictly regulated in most countries because of wrong doings of past platers. When the USA was far less populated, there were very few platers, so if they dumped their wastes in a pond or river, it did not have a significant effect on the environment. As the population grew and the industrial revolution made plated things more desirable, the number of platers grew and the amount they dumped was more per plater. In large cities, this led to some very high amounts of metals and other bad things in the land and waters.
By and large, if it is diluted enough, being acid or caustic is of little concern. If it is strong, it can seriously chemically burn the body.
Cyanide is probably over regulated. It takes very little to kill an adult by eating or drinking it or by converting it to a gas with an acid. Other than being converted to a gas, it is very nearly indestructible by the environment. Some, but extremely few places on earth are strong enough in acid to convert it. The terrible fear is that it will leach out into the drinking water and injure lots of people. The fact that it can be reacted with iron very easily forming a ferricyanide which is virtually indestructible except in boiling acid is not listened to.
All metals are bad if they are in excess, even minerals in your vitamins like iron and zinc. Chrome in the ion form, particularly the +6 valence causes cancer. Most metals form a fairly stable hydroxide, but still have to be buried in a highly regulated secure burial site which is very expensive.
Wastewater streams are water from a facility that is mostly from the rinse tanks, however some is from the treatment of tanks that are "dumped" into the treatment system.
Electroplating is very close today as to what it was 100 years ago. Some of the chemicals have changed slightly and there is a lot more science involved now. The biggest change is now we must treat the wastewater!
I have a book, "Modern Electroplating", dated 1898. That is 101 years old and it is amazingly similar to current methods.
I was in Cebu for a month or so in 1960. The island was extremely poor, but was beautiful. Find some older person that does not directly or indirectly gain from your islands tourist trade and ask them what they think of the "excess" amount of tourists that come there now. Many will talk about how nice it was 20 years ago or even 10 years ago.
Excess is the key to everything. Unfortunately, in your country and mine, there are a few who will do anything to make a dollar or a peso. 80 miles from where I live, a person recycled batteries and dumped the acid into a swamp in back of the shop.The acid contains quite a bit of lead and cadmium as well as several other metals in lesser amounts. They estimate that it will take 2,000 years for the swamp to get back to 50% of what it was before he started dumping.
Hope this helps some.
- Navarre, Florida
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