In an interesting eco-twist with the world's largest retailer, Wal-Mart Stores, Inc. (NYSE: WMT) stated yesterday that it will eliminate all laundry detergents from its shelves that are not packaged and sold in 'concentrated' form. In an effort to reduce waste and conserve natural resources, the company said that all U.S. Wal-Mart stores and Sam's Clubs would only sell concentrated detergent going forward, although a drop-dead date was not reported with the announcement.

After having strolled through Wal-Mart in the last 24 hours, I can say that much of the laundry detergent already sold by the retailer comes in concentrated form -- but then, there are many brands that are not. Procter & Gamble Co. (NYSE: PG) stated that they will start distributing smaller detergent containers for concentrated liquid detergent this year. P&G's larger brands are Tide and Downy, among many others.

The move is not really a surprise by Wal-Mart, which has been on a green warpath this year. This summer, the retailer announced that it would only accept smaller packaging from many of its vendors, and created a complete set of guidelines to help those vendors get packaging to where there would be minimal waste after purchase.

In addition to selling and promoting a huge assortment of energy-saving compact fluorescent light bulbs (CFLs), the company is taking steps to cut back (or even eliminate) high gas usage by its trucking fleet. All of these measures are part of the company's "Sustainability 360" plan. The plan includes these initiatives: saving more than 400 million gallons of water, 95 million pounds of plastic and 125 million pounds of cardboard over the course of every year. Now, those are some large numbers.

In May, I wrote about the decision by the major laundry detergent manufacturers to switch to selling more concentrated product: You would need less fluid per load, and therefore the bottles could be smaller and less heavy without sacrificing quality.

Now Wal-Mart Stores, Inc. (NYSE: WMT) is saying it will begin stocking the more concentrated products exclusively in an effort to conserve water, packaging and, of course, shelf-space. According (subscription required) to The Wall Street Journal, the original move by the manufacturers to switch to concentrated detergent was spurred by Wal-Mart, so it should come as no surprise that Wal-Mart will be making this move.

Wal-Mart will be launching an ad campaign to convince consumers that the concentrated product is just as good, but I have a better idea for how they could woo consumers -- the same question I asked back in May: Given all the cost savings associated with the smaller bottles, couldn't they pass some of it on to the consumer too?

As the champion of low prices, I hope Wal-Mart will make detergent cheaper for us.

Laundry detergent manufacturers have done it again; doubling the potency of detergent while cutting the bottle size in half. The Wall Street Journal talks about the marketing challenge that Procter & Gamble Co. (NYSE: PG), Unilever (NYSE: UL) and their competitors are about to face. The impetus for this move is not a greener earth or a more useful product, but instead, pressure from retailers like Wal-Mart Stores Inc. (NYSE: WMT) to squeeze more product into the same shelf space. You will be able to do just as many loads with half as much detergent, and the price will be the same per bottle. The problem is getting people to realize that and, more importantly, convince them that they aren't somehow getting ripped off.

As the Journal says, "Retailers are pushing the big shrink in detergent bottles because when their shelves are full with smaller bottles, they lose fewer sales to products being out of stock and less employee time is spent replenishing product. Retailers also save on transportation costs because more of the smaller bottles can fit on a truck. Meanwhile, manufacturers, which over the past two years have been hit hard by high oil prices, save on the petroleum-based plastic packaging as well as the costs of shipping to retailers."

Wal-Mart CEO Lee Scott's strategy of promoting the products as green-friendly makes sense, given how in vogue that is right now -- less plastic, less transportation -- it actually is environmentally friendly. But there's still the emotional, less rational problem: How do you convince someone to pay the same amount for 50 ounces as they used to pay for 100? And what's more, why do the retailers and manufacturers get all the benefits?