Original scientific paper

Transfer of suspended solids from public wastewater systems below 10,000 PE with mechanical preliminary treatment and secondary treatment

Goran Lončar orcid.org/0000-0002-6466-3677 ; Faculty of Civil Engineering, University of Zagreb, Zagreb, Croatia
Dražen Vouk ; Faculty of Civil Engineering, University of Zagreb, Zagreb, Croatia
Vesna Grizelj Šimić ; Hrvatske vode, Zagreb, Croatia
Nenad Leder ; Croatian Hydrographic Institute, Split, Croatia
Silvija Klapčić ; Faculty of Civil Engineering, University of Zagreb, Zagreb, Croatia
Ivan Mišura ; Faculty of Civil Engineering, University of Zagreb, Zagreb, Croatia
Filip Štos ; Faculty of Civil Engineering, University of Zagreb, Zagreb, Croatia

Abstract

The paper present a methodological approach to the analysis of transfer and settlement of suspen¬ded solids on the sea bottom from public wastewater systems of up to 10,000 PE while focusing on a comparison between different technological solutions for wastewater treatment plants (WWTPs). The results of the proposed methodology based on numerical modelling of the transfer of suspended solids in the sea will show differences in the sea bottom load with fine-grained particle sediment due to the implementation of different treatment levels. This will facilitate the establishment of a methodological standard to support arguments in the debate whether mechanical preliminary treatment presents adequate treatment level in individual cases or not. The proposed met¬hodology was applied to specific examples of the agglomerations Banjole, Premantura, Primošten, Dugi Rat, Bol, Gradac and Orebić (below 10,000 PE). The first variant analyses only mechanical preliminary treatment whereas the second one addresses secondary treatment on associated WWTPs. The results of the conducted research has shown that in the observed waters an average of 60 % of the total introduced suspended solids settle on the sea bottom from WWTPs with mechanical preliminary treatment, and 40 % if secondary treatment is implemented (with 90 % reduction in suspended solids at a WWTP). It was estimated that a maximum sea bottom load in the vicinity of submarine outfall diffusors equals ≈ 300 g/m2/year when mechanical preliminary treatment is implemented, and ≈ 25 g/m2/year if secondary treatment is implemented on both WWT Ps.

Keywords

coastal agglomerations; submarine outfall; suspended solids; numerical model

Hrčak ID:

192551

URI

https://hrcak.srce.hr/192551

Publication date:

27.12.2017.

Article data in other languages: croatian

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