| effluents(noun, type, water, ecosystem) |
| environs(noun, nature, ecology, world, ecosystem) |
| filtrate(verb, process, purification, decontamination) |
| groundwater(noun, type, water, ecosystem) |
| irreproachable(adjective, feature, characteristic, detail, purification) |
| purge(verb, process, purification, decontamination) |
| refine(verb, process, purification, decontamination) |
| sanitary(adjective, feature, characteristic, detail, purification) |
| sanitize(verb, process, purification, decontamination) |
| sewage(noun, type, water, ecosystem) |
| sewer water(expression, type, water, ecosystem) |
| sterilize(verb, process, purification, decontamination) |
| unadulterated(adjective, feature, characteristic, detail, purification) |
| unblemished(adjective, feature, characteristic, detail, purification) |
| uncontaminated(adjective, feature, characteristic, detail, purification) |
| unpolluted(adjective, feature, characteristic, detail, purification) |
| unsoiled(adjective, feature, characteristic, detail, purification) |
| unspoiled(adjective, feature, characteristic, detail, purification) |
| unstained(adjective, feature, characteristic, detail, purification) |
| untainted(adjective, feature, characteristic, detail, purification) |