Worldwide wastewater treatment observatory · 
Croatia
Aguas SB Observatory · public data to understand water
WWTP Zagreb
Croatia · official identifier HRUWWTP_0004008_001
1,200,000h-e design capacity (2022) · 1st of 115
European Environment Agency — Waterbase-UWWTD, data call 2023 (versión final pública) · official identifier HRUWWTP_0004008_001 · reported size 1,200,000 h-e design capacity · received load 819,761 h-e · reported treatment: PS · data year 2022. 1st of 115 records with reported size in the inventory of Croatia; 27.5 % of the sum of those 115 records in h-e (sum of records, not national capacity); nearest inventoried plant at 8.6 km · 1 within 10 km. Reported data with their source; estimates are not measurements of the plant.
Aguas SB does not manage this wastewater treatment plant.
WHAT THE DATA REPORT
Reported data official data · 2022
| Treatment | primary + secondary (as reported to the EEA: PS) · reported levels |
|---|---|
| Nitrogen removal | not reported |
| Phosphorus removal | not reported |
| UV disinfection | not reported |
| Status | active |
| Reported coordinates | 45.7925, 16.0819 precision reported by the source: level 2 what it means |
| Source and year | European Environment Agency — Waterbase-UWWTD, data call 2023 (versión final pública) · dataset record |
FUENTES PÚBLICAS
What public sources report
Documented milestones
- 2007-09-26 · Zagreb City Council announced completion of the city’s central wastewater treatment plant. Ayuntamiento de Zagreb
Facts taken from public documents, with their date and link; an authorisation, a project or a planned capacity do not prove operation or quantities actually treated. Aguas SB editorial layer, lot L02; it does not change the official data.
REGULATORY REFERENCES
Referencia normativa: Croatia
Regulatory framework of Croatia · Directive (EU) 2024/3019: reported-capacity band 150,000 p.e. or more; obligations are set by agglomeration load, not by the capacity of this plant. Individual applicability is not determined in this profile.
SCENARIO
Reference energy scenario for this load estimate · simulator engine
what this estimate is · Inputs: 819,761 p.e. of reported load; equivalent average load 819,760 p.e. with the reference profile of Croatia (hypothesis with reported load and reference profile; not a measurement). Open this scenario in the simulator · how it is calculated and what it is not.
Reference scenario computed on the server from the reported load and the country profile; an estimate, not a measurement. The simulator recomputes it when opened.
WATER THAT COULD RETURN
Reuse potential
what this estimate is · Volume estimated from the reported load (163,952 m³/day of reference), not measured or available for reclamation.
NEARBY PLANTS
Nearby wastewater treatment plants
| Plant | Distance | Capacity (h-e) | Load 2022 | Treatment |
|---|---|---|---|---|
| Velika Gorica | 8.6 km | 35,000 | 45,776 | primary and secondary |
| Rugvica | 13.1 km | 25,000 | 15,464 | primary and secondary |
| Brckovljani-Božjakovina | 17.3 km | 8,400 | 1,474 | primary and secondary |
| Sveti Ivan Zelina | 20.3 km | not reported | 3,221 | not reported |
| Zaprešić | 21.3 km | 61,000 | 34,818 | primary |
Distances are between reported coordinates; proximity does not establish a hydraulic connection.
QUESTIONS
Frequently asked questions about this plant
What capacity does WWTP Zagreb report?
Reported size: 1,200,000 h-e design capacity. Received load: 819,761 h-e. Units are retained without conversion.
What treatment is reported?
Treatment PS. Nitrogen, phosphorus and UV are shown only when explicitly reported.
How much energy would a reference plant use with the load of Zagreb?
Aguas SB simulator reference scenario for 819,761 p.e. of reported load: 22,960,816 kWh per year (28.0 kWh per p.e. of average load), with aeration as 65 % of consumption. Estimate with the country reference profile; not a measurement of the plant.
SOURCE AND CORRECTIONS
Source
reported data · European Environment Agency — Waterbase-UWWTD, data call 2023 (versión final pública) · data 2022 · edition 2023 · source licence: CC BY 4.0 · JSON for this plant · suggest a correction · catalogue 2026-11-06. Reported data, not a current inspection; no compliance judgements.