Naslov (eng)

Relevance of Probability Distribution of Effluent Quality Parameters for the Treatment Plants Design

Autor

Mitrinović, David
Perović, Marija
Popović, Miodrag
Kovačević, Srđan
Matić, Branislava

Publisher

Opis (eng)

The basic legislative requirements for the wastewater treatment plants (WWTPs) are that the quality of selected parameters in effluent should be below the stipulated values, and that this is considered to be fulfilled if no more than certain percent of samples during one year do not conform to limits. In the Serbian legislation, for WWTPs with capacity larger than 50,000 PE minimal number of samples (24h composite) per year is 24, of which 3 can be non-conforming (12.5%), providing that the BOD5 and TSS value are not more than 100% and 150% above the limit, respectively. The starting point for setting the inlet quality used in the design is the probability distribution of legislatively relevant wastewater quality parameters. For sewage outlet “Sajam”, largest in Belgrade, Gumbel distribution of BOD5 concentrations provided the best match with the laboratory determined values, with mode (most frequent value) 250 mgO2/l and scale parameter 60 mgO2/l. In order not to overstep the limit value in more than 12.5% of samples, wastewater with the BOD5 concentration of 390 mgO2/l, which is 90th percentile, should be used in the design. The designed WWTP based on this value should be tested (using software modeling tool or calculation spreadsheet used for developing the design) on 99.9th percentile of BOD5 concentration i.e. 640 mgO2/l, present in the influent approximately ones in 1000 sampling, or once in 40 years (which is more than the normal lifespan of the plants) for 24 samples a year. If the calculated effluent BOD5 concentration is less or equal to 200% of 25 mgO2/l limit value (50 mgO2/l) for this BOD5 concentration then all the conditions stipulated in the legislations will be met. The same methodology should be used for COD and TSS.

Jezik

engleski

Datum

2025

Licenca

© All rights reserved

Predmet

WWTP, Legislation, Probability distribution

Deo kolekcije (1)

o:243

Institut za vodoprivredu "Jaroslav Černi"