In one end goes waste water laden with alcohols. Out the other end comes the same water, minus the alcohols. The water is safe to send into the local sewer; the alcohols go into storage tanks to be reused for manufacturing.
Clean. Silent. Computer-controlled. No human hands need touch the liquids. Price tag: about $1 million.
The system just described is a working solvent-recovery unit at Polaroid Corporation's Freetown, Mass., plant. Company environmental affairs director Harry Fatkin calls it, ''the ultimate in resolving the hazardous waste problem.''
Whether by cutting the volume of dangerous wastes produced in manufacturing or by participating in the growing number of waste-exchange programs - or both - companies around the United States are steadily awakening to the need to solve that problem.
And once the US economy emerges from the doldrums, some observers suggest, an even greater commitment in the area may be forthcoming.
These efforts come at a fortuitous time.
By various estimates, as many as 130 billion pounds of toxic wastes a year are produced in this country. Not all of that volume comes from manufacturing. But more than half of it - 80 billion pounds - ends up in landfills.
These landfills, or dumps, are still the cheapest - and most dangerous - means of waste disposal. The recent experience in Warren County, N.C., where a proposal to establish a landfill to store hundreds of tons of PCB-laden soil met with intense local opposition, suggests that landfills have become so controversial that establishment of new ones anywhere may already be impossible without a loud and prolonged period of public protest.
Industry's response to the problem is driven by three factors: tough federal and state rules on dangerous wastes; the profit motive; and a sense of social responsibility.
''Economically, it's becoming more and more imperative,'' says Kathleen Durso-Hughes of the Environmental Action Foundation's waste and toxic substances project in Washington. ''Companies are starting to look seriously at what they used to throw away. . . .''
A spokesman for Sommer Metalcraft, a Crawfordsville, Ind., electroplating firm whose waste-recycling program is a recognized leader in the industry, agrees. ''This is a sensitive subject in every plant in the country,'' he says.
Sommer Metalcraft, a small company, was able to reduce its consumption of chromium from nearly 200 pounds per shift to fewer than 200 pounds a month by installing an evaporator that allowed for recovery of the valuable metal from its rinse tanks. Its investment in the sophisticated recycling equipment was recouped in one year. Before the recycling equipment was installed, highly toxic chromium was disappearing down the drain with the waste water.
Other firms report proportionate savings or added profits from their recycling efforts that are equally impressive.
Generally, the response by private industry to the hazardous waste problem dates back to the mid-1970s and passage by Congress of the Resource Conservation and Recovery Act (RCRA), which regulates the labeling, transportation, treatment , and disposal of such wastes. Indeed, such giant corporations as Minnesota Mining & Manufacturing, Westvaco, Eastman Kodak, and Dow Chemical - to name a few - began modifying their manufacturing processes at that time to extract extra salable products from raw materials or to recycle wastes for reuse in their own plants.
Many others have since followed suit. Monica Campbell of the Pollution Probe Foundation, a Toronto-based public-interest group that studies such matters here and in Canada, reports: ''The rogues' gallery of worst polluters of the 1960s'' is becoming a list of the ''corporate environmentalists of the 1980s.''
But Even industry sources say there still is considerable room for improvement. ''Because we have a stagnant economy, less waste is being generated anyway,'' says Mark Griffiths, associate director of environmental programs for the National Association of Manufacturers in Washington. ''(But) reduced generation is the future.'' At the moment, the National Association of Manufacturers does not actively promote source reduction among its 12,000 member firms, viewing its first priority as encouraging them to comply with RCRA instead.
In a report issued last August, the noted Cambridge, Mass., research firm, Arthur D. Little Inc., concluded that the volume of hazardous waste generated in New England is unlikely to drop significantly any time soon and that ''the high cost of . . . disposal provides considerable incentive to reduce or eliminate waste.''
Much depends on how waste is defined, environmentalists say. Most agree that it is a mistake for companies to regard their wastes as ''garbage'' or ''junk.'' Call them that, these sources argue, and you have created a state of mind that is not conducive to source reduction or recycling.
Consequently, says Ms. Durso-Hughes, decisions on waste management in businesses across the country are increasingly being ''kicked higher and higher up the administrative ladder.''
The key to enlightened management, environmentalists agree, is keeping separate the waste materials that once were routinely mixed at the end of the manufacturing process. Only then can valuable components be recovered.
Some of the impetus for more enlightened management is coming from the states. North Carolina, Michigan, Minnesota, Wisconsin, and Oregon offer tax breaks for companies that reduce or recycle their wastes. Kansas, Indiana, Maine , Florida, and New York are among those that charge industries for the ''privilege'' of generating hazardous waste. California and New York also provide industry with technical assistance to find alternative disposal and reduction techniques. California, in fact, requires generators of wastes to justify their choice of disposal over recycling.
Oregon informally asks generators of chemical wastes in the state to look into the feasibility of recycling.
Until source reduction more fully takes hold, waste-exchange programs are the principal alternative means of lightening the burden on landfills. Their premise: that one manufacturer's waste is someone else's raw material. Sewage plants, for example, are increasingly using discarded, acid-laden fluids - called pickling liquors - from steelmakers to treat their municipal sludge.
Regional clearinghouses for these exchange programs are usually run by state governments, trade associations, or chambers of commerce. They either maintain lists of wastes that one firm wants to transfer along with lists of potential users or else they ''broker'' wastes between generators and reusers.