A Quick, low-cost treatment method for secondary effluent nitrate removal through denitrification

Díaz, R.; Garcia, J.; Mujeriego, R.; Dantas Filho, Manoel Lucas

A Quick, low-cost treatment method for secondary effluent nitrate removal through denitrification

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dc.contributor.author	Díaz, R.
dc.contributor.author	Garcia, J.
dc.contributor.author	Mujeriego, R.
dc.contributor.author	Dantas Filho, Manoel Lucas
dc.date.accessioned	2020-11-06T13:37:11Z
dc.date.available	2020-11-06T13:37:11Z
dc.date.issued	2004-07-29
dc.description.resumo	The objective of this work was to develop an experimental treatment method for nitrate removal from secondary effluents through denitrification. Three plant substrates (pine bark, almond shells, and walnut shells) were used as organic carbon sources for denitrification and as a medium for the denitrifying bacteria. Experiments were carried out using eight cylindrical open-air batch reactors with a diameter of 16 cm and a height of 21.5 cm. Each pair of batch reactors was filled with one of the plant substrates, and additionally, one pair was filled with gravel and used as a control. Additional experiments were conducted using a rectangular, open-air, continuous-flow reactor filled with almond shells, which had a length of 70.5 cm, a width of 28 cm, and a height of 30 cm. Nitrate removal was evaluated as a function of hydraulic retention time (1, 2, and 3 days for batch reactors and 16 and 24 h for the continuous reactor), water temperature (13 and 20°C for batch reactors and 15, 20, and 25°C for the continuous reactor), influent nitrate concentration (only in the case of the batch reactors, 18.5 and 35 mg NO3--N/L) and type of reactor. The efficiency of the nitrate removal was seen to be dependent on the hydraulic retention time, temperature, and influent concentration. Under all the conditions tested, walnut shell batch reactors were more efficient (removal rates from 9.6 to 18.4 g NO3--N/m3 · day) than the batch reactors filled with the other substrates (removal rates from 4.6 to 8.5 g NO3--N/m3 · day for bark pine and 4.7 to 7.3 g NO3--N/m3 · day for almond shells). The control gravel reactors did not remove nitrate. From the data obtained it is concluded that walnut shells are more effective than almond shells and pine bark, because they produce a larger quantity of organic matter, which is also more easily biodegradable. The continuous-flow reactor filled with almond shells was more effective for nitrate removal than the batch reactors filled with the same substrate (11.3 to 17.6 g NO3--N/m3 · day). Water circulation in the continuous-flow reactor apparently favors the rate of organic matter release and dispersion, which in turn, improves denitrification. The main concern of this treatment method is the increase in effluent COD concentration produced by organic matter release; nevertheless, the effluent COD was, in general, below the limit set by the European Directive 91/271 in all experiments	pt_BR
dc.identifier.citation	DIAZ, R.; SERRANO, J. G.; MUJERIEGO, R.; LUCAS FILHO, M.. A Quick, low-cost treatment method for secondary effluent nitrate removal through denitrification. Environmental Engineering Science, London, 2003. Disponível em: https://www.liebertpub.com/doi/10.1089/109287503770736195. Acesso em: 22 out. 2020. https://doi.org/10.1089/109287503770736195	pt_BR
dc.identifier.doi	10.1089/109287503770736195
dc.identifier.issn	1092-8758
dc.identifier.issn	1557-9018
dc.identifier.uri	https://repositorio.ufrn.br/handle/123456789/30520
dc.language	en	pt_BR
dc.publisher	Mary Ann Liebert	pt_BR
dc.rights	Attribution-NonCommercial 3.0 Brazil	*
dc.rights.uri	http://creativecommons.org/licenses/by-nc/3.0/br/	*
dc.subject	Nitrate removal	pt_BR
dc.subject	Denitrification	pt_BR
dc.subject	Nutrient removal	pt_BR
dc.subject	Urban wastewater treatment	pt_BR
dc.title	A Quick, low-cost treatment method for secondary effluent nitrate removal through denitrification	pt_BR
dc.type	article	pt_BR