Oxidation ditches: wastewater treatment plants in Pennsylvania
45 plants · 6% of the state · 87 MGD reported by 44 plants
Klarifi identifies 45 publicly owned wastewater treatment plants with oxidation ditches in Pennsylvania, 6% of the 783 plants in the state (87 MGD reported by 44 plants). The largest is City Of Allentown Wastewater Treatment Plant in Allentown at 31.07 MGD.
Oxidation ditches are ring-shaped activated sludge reactors with long retention times, common at plants between 0.5 and 10 MGD. They are recognisable from the air by their looped channels and rely on surface aerators or brush rotors, which are frequent replacement and energy-efficiency projects.
The largest oxidation ditch plants in Pennsylvania
| # | Facility | City | Avg flow (MGD) | NPDES permit | Expires | Violations (3y) |
|---|---|---|---|---|---|---|
| 1 | City Of Allentown Wastewater Treatment Plant | Allentown | 31.07 | PA0026000 | Sep 2007 | 0 |
| 2 | Wyoming Valley Sani Auth Wilkes Barre | Wilkes Barre | 17.3 | PAL026107 | Dec 2030 | 1 |
| 3 | Reading STP | Reading | 14.09 | PA0026549 | Apr 2028 | 9 |
| 4 | Hanover Boro STP | Mcsherrystown | 3.65 | PA0026875 | Dec 2027 | 2 |
| 5 | Ephrata STP | Ephrata | 1.93 | PAL027405 | Dec 2030 | 18 |
| 6 | Elizabethtown STP | Elizabethtown | 1.7 | PA0023108 | Apr 2027 | 8 |
| 7 | Harvey Avenue STP | Doylestown | 1.1 | PA0021172 | Apr 2027 | 0 |
| 8 | Berwick Mun Auth | Berwick | 1.02 | PAL023248 | Dec 2030 | 4 |
| 9 | Warren City WWTP | Warren | 0.99 | PA0027120 | Oct 2022 | 4 |
| 10 | Myerstown STP | Myerstown | 0.97 | PA0021075 | Mar 2026 | 0 |
| 11 | Spring Twp STP | Sinking Spring | 0.94 | PA0043052 | Oct 2030 | 4 |
| 12 | Ephrata Reg 2 STP | Ephrata | 0.9 | PA0087181 | Jul 2026 | 9 |
| 13 | Punxsutawney Boro STP | Punxsutawney | 0.78 | PAL020346 | Dec 2030 | 2 |
| 14 | New Holland WWTP | New Holland | 0.78 | PAL021890 | Dec 2030 | 23 |
| 15 | Amity Twp WWTP | Douglassville | 0.73 | PA0070351 | Apr 2028 | 14 |
| 16 | Saxonburg Area Authority STP | Renfrew | 0.62 | PA0029122 | Nov 2030 | 22 |
| 17 | Highspire Boro - STP | Highspire | 0.58 | PA0024040 | Feb 2027 | 2 |
| 18 | Mainland STP | Harleysville | 0.5 | PA0056413 | Nov 2026 | 10 |
| 19 | Littlestown STP | Littlestown | 0.5 | PA0021229 | Aug 2030 | 4 |
| 20 | Manheim STP | Manheim | 0.48 | PA0020893 | Mar 2027 | 2 |
| 21 | Coudersport Area Mun Auth STP | Coudersport | 0.48 | PA0043419 | Jul 2031 | 14 |
| 22 | Maidencreek Twp STP | Reading | 0.47 | PA0070271 | Mar 2030 | 3 |
| 23 | Hamburg Boro STP | Hamburg | 0.47 | PA0021601 | Jan 2030 | 1 |
| 24 | New Hanover Twp Auth STP | Gilbertsville | 0.42 | PA0057819 | Feb 2030 | 1 |
| 25 | Fleetwood Boro STP | Fleetwood | 0.38 | PA0021636 | Oct 2030 | 20 |
Contacts and project signals for every plant on this list
Klarifi adds verified decision-maker contacts, permit limits, discharge monitoring data and the capital projects planned in each city, filterable by technology, size and compliance record.
Other technologies in Pennsylvania
Oxidation ditches in other states
Oxidation ditches in Pennsylvania: questions
Sources and methodology
Flow, permit and violation figures come from the EPA's ICIS-NPDES discharge monitoring records. Population served comes from the Clean Watersheds Needs Survey 2022. Treatment structures are identified by Klarifi's review of aerial imagery, and capital improvement projects are extracted from published municipal budget documents. Violations are counted over the last three years of monitoring reports.
Data refreshed September 11, 2026.