I hadn't heard that branched chain or linear chain surfactants could replace water softeners like zeolites or complex phosphates in laundry detergents. Usually those are two separate functions, except of course in a natural soap, in which case one gets soap scum as a reward of dubious distinction.
I might have bestowed mild praise upon zeolites at some point, but only in the event that otherwise they might be replaced by just more cheap washing soda, which instead of leaving fluffy gray white lint everywhere will leave nasty cement-like hard water precipitates everywhere. STPP still is far and away the best laundry water softener out there, as well as being and excellent break, alkalinizer, saponifier, stain remover, etc. It is only for alleged environmental reasons that complex phosphates have been discouraged in laundry products - not out of any deficiency in their cleaning performance.
When I was research STPP vs. Zeolites some years back, I came across some articles that expressed concern about the effect that large amounts of zeolites in the municipal waste stream would have on sludging up waste water treatment plants. And that sludge would have to be disposed of somewhere. The argument (made by the Phosphate Industry Council, of course) was that the cost of dealing with zeolite sludge could be equivalent to the cost of removing phosphates from the waste stream, with the added benefit that the phosphate by-product, calcium phosphate, could be used in poultry feed and in fertilizers, further defraying the cost.The same articles proposed that phosphates further could play a beneficial role in fresh water bodies, by buffering the waters and thus counteracting the toxic effect of acid rain. But in such cases the main pollutant, nitrogenous compounds (such as nitrites/nitrates) must be tightly controlled or algal over-growth may occur.
