| AS | activated sludge |
| BOD | biological oxygen demand |
| BTC | biological treatment capacity |
| BTT | biological treatment technology |
| CAP | cation active polyelectrolyte |
| CAPew | equivalent weight of cation active polyelectrolyte |
| COD | chemical oxygen demand |
| DO | dissolved oxygen |
| EW | equivalent weight |
| HNEPP | Hungarian National Environmental Protection Programme |
| IMEKO | International Measurement Confederation |
| IR | infrared |
| MT | mechanically treated |
| MZ | modified zeolite |
| MZA | modified zeolite addition |
| NBWTP | North-Budapest Wastewater Treatment Plant |
| OC | organic carbon |
| OVH | National Water Authority in Hungary |
| STP | sewage treatment plan |
| SVI | sludge volume index |
| TOC | total organic carbon |
| WT | wastewater treatment |
| WTC | wastewater treatment capacity |
| WTP | wastewater treatment plant |
| WTT | wastewater treatment technology |
| ZEORAP | wastewater treatment technology applying modified zeolite |
| zeoliteew | equivalent weight of zeolite |