| Keyword | CPC | PCC | Volume | Score |
|---|---|---|---|---|
| how was sewage treated before the 1900s | 2 | 0.3 | 2452 | 43 |
| when was sewage invented | 1.71 | 0.2 | 998 | 77 |
| when was the sewage system invented | 1.7 | 0.1 | 1768 | 79 |
| how sewage is treated | 1.01 | 0.3 | 5165 | 38 |
| history of wastewater treatment | 0.36 | 0.1 | 4034 | 98 |
| history of sewage systems | 0.29 | 0.1 | 2888 | 26 |
| sewage system history uk | 0.36 | 0.1 | 9641 | 98 |
| detail information about sewage treatment | 0.79 | 0.3 | 9305 | 21 |
| how is sewage treated uk | 0.57 | 0.5 | 804 | 68 |
| sanitation in the 19th century | 1.65 | 0.7 | 1759 | 99 |
| how to treat sewage | 2 | 0.2 | 9591 | 37 |
| what is treated sewage | 1.82 | 0.9 | 392 | 59 |
| sanitation during the progressive era | 0.8 | 0.4 | 8067 | 79 |
| who invented the sewage system | 1.8 | 0.6 | 2971 | 38 |
| sewage treatment process pdf | 0.97 | 0.6 | 9976 | 90 |
| in primary treatment of sewage | 0.71 | 0.5 | 1178 | 77 |
| london sewage system history | 0.75 | 1 | 7609 | 76 |
| when did wastewater treatment start | 0.24 | 0.3 | 1972 | 76 |
| when were sewers introduced | 0.3 | 0.9 | 6523 | 90 |
