Does sewage water become pure after refining and recycling it?

Question 8: What is the ruling on using sewage water to perform Wudoo’ (ablution) or Ghusl (ritual bath) after it has been treated?

A: All Praise is due to Allaah Alone and peace and blessings be upon His Messenger, his family, and companions. To commence: The Council of Senior Scholars has studied this matter before in the Kingdom of Saudi Arabia and issued a decision regarding it to the following content: The council has read the study that was made on this matter by the Permanent Committee for Scholarly Research and Ifta’. The council has also read the letter of his Excellency, the Minister of Agriculture and Water No. 1 / 1299 on 30/05/1398 A. H. After studying and discussing the matter, the following was decreed… read more here.

What is the ruling on performing Ghusl in standing water for the one who is Junub

Question 2: What is the legal ruling on performing Ghusl (ritual bath) in standing water for someone who is Junub (in a state of major ritual impurity)?It should be noted that there are many ponds in desert places where water remains standing for a long period without being changed except by rain water in summer or autumn. There are also some ponds in Masjids (mosques). What is the ruling on the prohibition mentioned in Hadith: “None of you should wash in standing water while he is Junub.” ? What is the ruling on a person who does what is prohibited? Moreover, villagers used to come to these ponds and reveal some parts of their bodies above the knees?

Answer: All Praise is due to Allaah Alone and peace and blessings be upon His Messenger, his family and Companions. To commence: Firstly: It is not permissible for the Junub to perform Ghusl in standing water. It was reported by Muslim on the authority of ‘Aboo Hurayrah… read more here.