Talk to Geric, a man with a mask covering his mouth, sitting on the floor near the path to the Old Muckworks, to start this mission. This is a level 6 Heroic 2+ mission, meaning it is supposed to be done with at least two players level 6 and above. But since this particular quest does not require much killing, it is soloable, and you should be able to solo it even at level 5 by being careful and evading the tougher enemies.
Geric: Excuse me - yeah, over here. I know, I sound strange, you don't have to say it. Forty years I worked in the factories by the river, breathing the noxious poisons they produced. Made a fair number of credits. But now my lungs are useless. Spine is bent from hard labor. I can't do anything for myself I gotta ask for help from someone strong like you.
You can ask him:
What do you need?
Not sure how helpful it'll be
Why should I care?
Ask him what he needs. He tells you that before the effects of Hutta's pollution made him an invalid, he set up a pollution treatment system to clean the river. Every extra credit he had went into maintaining that system - until the settlers on the river drove him out. You can say:
Why did they do that?
People are disgusting
I couldn't care less
Choose the first option to ask him how come the settlers were not grateful for his help. He tells you that it's the vile Hutta, they bought off the settlers and spread lies about his work, all to preserve their precious industry. That industry is the cause of all of Hutta's problems. The filth, the poison - comes from their pipes and smokestacks. The river needed only one more treatment to be free of their vile filth. All he is asking is that you take the last treatment to the river.
Tell him that sure, you will do it. He gives you a canister that contains the purifying chemicals and tells you that the filtration system's up at the Old Muckworks.
Check your quest log:
[Heroic 2+] The Man with the Steel Voice
Repeatable - This mission can be repeated once per day. It is reset in the morning
Geric, a sickly old man with an artificial lung, has asked you to release his cleaning solution into the polluted waters at the Old Muckworks. He is sure it will cleanse the water and prevent others from getting sick. Find the filter station outside the Old Muckworks.
Your first task is to investigate the Filter Station.
From the Evocii Work Camp, travel northwest through the River Lands. Use the map to locate the Filtering Station, a big device near the Old Muckworks. After you find the station, speak to Bow La standing near by. She asks you if you know what the foul chemicals you hold do. They purify the water all right, but they also do disgusting things to the water beasts - mutating them and making them rampage. They come out of the water twice the size and ten times as vicious, and they wipe out the villagers in the area.
Your choices of dialog are:
Do you think the guy knows?
That's awful
And I missed the fun?
Choose the first option to tell her that you think the old man did not realize what the chemicals did. She says that just because he is old and dying, doesn't mean he is innocent. That old man is crazy. He clearly doesn't care if they all die in his purification process. If you want to help, you should go to that station and smash the valves in back that release the chemicals, so no one can use that station ever again.
You can say:
What about the pollution?
Pay me.
I like breaking things
If you tell her to pay you for this favor, she tells you she can only offer a few credits. They are not a wealthy village but it'll be worth it to keep the monsters at bay. She begs you to help them. You now face a LIGHT/DARK conflict:
Better to clean the water (DARK)
Yes, I'll protect the people (LIGHT)
The mission will branch according to the path you take.
Dark Path - Proceeding with the purification process
If you elect to go on with the water purification, you tell her that you are going to purify the river. You get 50 dark points. She calls you a heartless murderer. Your task now is to apply chemicals to the filter station. Go back to the station and interact with the tall rod there. Then go back to the work camp to speak to Geric. Tell him you have purified the river. You tell him that pollution is no longer a problem, but the monsters are. He says that if someone doesn't like angry monsters coming out of the river, they shouldn't live near the river. As a reward, he gives you a mpa that lears to some useful things he hid in the industrial zone in his younger days. You can now proceed to find the hidden cache, which is northeast of Jiguuna. Locate it on the map and make your way there. Open it to get your reward.
Light Path - Destroying the Filtering Station
Choosing this option, you tell Bow La that you will destroy the valve, and get 50 Light points. Your tasks now are to destroy the Southeast, West, Northwest, and Northeast Filter control valves. Find them on the map and destroy them one by one. Then speak to Bow-La again. She thanks you. Next, you need to return to Geric on the path to the old Muckworks to tell him of your decision. Tell him you broke the valve, because the purification process was driving violent monsters from the river and into nearby villages. Geric is upset that you listened to the settler, to the Hutt lies. According to Geric, the Hutts pay those settlers to live by the river so everyone will think the river is safe. And then the settlers work in the industrial zone and dump more dangerous chemicals into the river. Nasty, vicious cycle and they deserve what they get.
This concludes the mission, The Man with the Steel Voice.