Why does washing powder/detergent contain(include) phosphate? (Why is phosphate included in washing powder?)

[?] Why do many washing powders/detergents contrain phosphate? Are phosphates (a) necessary (indispensable, essential) constituent/part? How dangerous(perilious, hazardous) are they for nature? What kind of (Which) substitutes are included (contained, hidden) in the so-called eco washing powders/detergents?

[!] Phosphates perform (serve for, have) multiple (many) functions in washing powders/detergents. Above all (notably, first of all, first and foremost) they soften (deharden) water by binding (bonding with) calcium ions. Thus (by that, through it, that way, that's why) they prevent the lime included (contained) in [the] water from depositing (settling) inside (on) the textile fibres. If the water is hard and contains (containing) much dissolved lime, its ability to dissolve soap diminishes (decreases, is reduced, lessens, diminishes): The cleaning (washing) power deteriorates (decreases, eases off, is weakened, is going off, is slowing down, dropping off).

Moreover (further(more), besides) phosphates stabilize the pH value thus intensify (enhance) to surface active substances of water. They keep the dissolved dirt in the water and prevent it from penetrating (repenetrating) into the clothes again.

That fact that for several years increasingly no-phosphate washing powders/detergents are produced (the fact that no-phosphate washing powders have been increasingly produced for several years) is due to (can be brought back to, is connected/related to/with) the environmental impact (load) caused by phosphates. For (because) phosphates favo(u)r [the] growth of algea in seas and watercourses. When the algea die (with the algea dying off), the water's oxygen content (of the water) decreases.

As substitutes NTA (nitrilotri acetic acid), zeolith A and citric acid are mostly (most widely) used. NTA softens (dehardens) the water and possesses (has) favo(u)rable (good) washing properties (results)(properties for washing), but it is hard to be degraded (is degraded only with difficulties) and can (re)dissolve heavy metals deposited in [the] river sludge. Zeolith A softens (dehardens) water and is non-toxic (harmless) but does not have any (possesses no) washing properties. Citric acid softens (dehardens) water as well and is biodegradable. Yet (but) (neither does it have) it has no washing properties, either (as well).

Thus, none of these substances as such (on its own) is able to (can by itself) replace all of the phosphates' washing properties. Totally equivalent and harmless substitutes don't exist so far (are not available, yet). (Up to this time there are no completely equivalent (equal) and harmless (safe) substitutes.) Therefore, (that's why) washing powder/detergent producers continue finding themselves (feel to be, find themselves) compelled (forced) to add a certain amount of phosphate to [the] washing powder/detergents. [Consequently,] the sewage has to (must) be purified (cleansed, refined) in chemical sewage (purification) plants (sewage treatment systems).

words:

yet - dennoch, aber

to compel - (er)zwingen