Purity: Does Treated Sewage Water Become Pure Through Filtration and Metamorphosis?

Practical Laws of Islam as per the teachings of Imam Khamenei

Purity: Does Treated Sewage Water Become Pure Through Filtration and Metamorphosis?

English:

Question #87

Scientific studies have shown that after sewage system water mixes with mineral pollutants and germs its specific gravity becomes ten percent more than the normal water. The filtration plant changes the water obtained from the sewage system and separates these materials and germs from them through physical, chemical and biological operations. Hence, after being purified in various respects — physically (color, taste, and odor), chemically (removal of mineral pollutants), and hygienically (removal of harmful germs and parasites ova), it becomes by far much cleaner and better than the water of many rivers and lakes, especially the water used for irrigation. Does najis drainage water become pure by the aforementioned process and does the rule of metamorphosis apply to this type of water? Or is the water, after going thorough such a process of filtration, ruled to be najis?

Answer #87

Metamorphosis would not be achieved just by separating mineral pollutants, germs, etc., from drainage water unless the purification process is done by evaporating the water and condensing its vapor into water again.

- Imam Khamenei, Practical Laws of Islam, Rules Concerning the Different Types of Water