| Keyword | CPC | PCC | Volume | Score |
|---|---|---|---|---|
| how was sewage treated before the 1900s | 0.07 | 0.8 | 1423 | 52 |
| when was sewage invented | 0.14 | 0.9 | 3902 | 44 |
| when was the sewage system invented | 0.16 | 0.7 | 6434 | 5 |
| how sewage is treated | 0.4 | 0.5 | 113 | 95 |
| history of wastewater treatment | 0.52 | 0.5 | 9977 | 27 |
| history of sewage systems | 1.78 | 0.8 | 1324 | 80 |
| sewage system history uk | 0.5 | 1 | 7821 | 74 |
| detail information about sewage treatment | 0.71 | 0.6 | 1012 | 77 |
| how is sewage treated uk | 0.75 | 0.9 | 172 | 52 |
| sanitation in the 19th century | 1.22 | 0.1 | 956 | 69 |
| how to treat sewage | 1.34 | 0.7 | 6969 | 19 |
| what is treated sewage | 0.65 | 0.4 | 5793 | 14 |
| sanitation during the progressive era | 0.91 | 0.8 | 6349 | 20 |
| who invented the sewage system | 1.13 | 0.7 | 3015 | 15 |
| sewage treatment process pdf | 0.26 | 0.1 | 8018 | 40 |
| in primary treatment of sewage | 0.74 | 0.5 | 9692 | 5 |
| london sewage system history | 1.74 | 1 | 1495 | 71 |
| when did wastewater treatment start | 1.61 | 0.7 | 9083 | 83 |
| when were sewers introduced | 1.09 | 1 | 1543 | 92 |
