Enhancing urban wastewater treatment: Chlorella vulgaris performance in tertiary treatment and the impact of anaerobic digestate addition

• Type: Article in International Scientific Journal
• Date: 2024

Authors

Sousa, SA (Author) Other; Esteves, AF (Author) FEUP; Ab, EMS (Author) Other; Pires, JCM (Author) FEUP

Journal

The Journal is awaiting validation by the Administrative Services.

Title: ENVIRONMENTAL TECHNOLOGY & INNOVATION

Vol. 34

ISSN: 2352-1864

Indexing

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Other information

Authenticus ID: P-010-4TD

DOI: 10.1016/j.eti.2024.103601

Abstract (EN): The rising urban wastewater discharge into waterways resulted in harmful environmental effects. Microalgae can bioremediate wastewaters by removing contaminants such as nitrogen and phosphorus and can be rather tolerant to toxic compounds. Managing the anaerobic digestate resulting from sludge treatment in wastewater treatment plants faces some obstacles related to its high contaminant content. This work aims to study the ability of the microalga Chlorella vulgaris to perform the tertiary treatment of urban wastewater, assessing its growth, nutrient removal and the effect of the addition of digestate at different concentrations in this treatment phase. A secondary effluent was supplied with 1% (M1), 5% (M5) and 10% (M10) (v/v) of anaerobic digestate and used to culture microalgae. An assay using only secondary effluent was also performed (S). C. vulgaris grew successfully in all effluents except for the M10, and the highest specific growth rate was obtained in the M1 assay, 0.35 +/- 0.01 d( -1 ). Ammonium -nitrogen was completely removed in the S, M1 and M5 assays ( >99.9%). Microalgae successfully removed phosphatephosphorus from the tested effluents, achieving a negligible concentration in the M1 assay and a removal efficiency of 96.2 +/- 0.2%, 51 +/- 2%, and 43 +/- 3% in S, M5 and M10, respectively. These results showed that microalgal cultures could efficiently remediate the secondary effluent and its mixture with 1% (v/v) of anaerobic digestate, achieving nutrient concentrations below the current legislation limits and the more restrictive limits predicted for future legislation.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 14