Evaluation of an Effluent Treatment Strategy to Control Nitrogen From a Recirculating Aquaculture Facility

Brazil, Brian Ligar

Evaluation of an Effluent Treatment Strategy to Control Nitrogen From a Recirculating Aquaculture Facility

dc.contributor.author	Brazil, Brian Ligar	en
dc.contributor.committeechair	Love, Nancy G.	en
dc.contributor.committeemember	Novak, John T.	en
dc.contributor.committeemember	Boardman, Gregory D.	en
dc.contributor.department	Environmental Engineering	en
dc.date.accessioned	2014-03-14T20:46:46Z	en
dc.date.adate	2001-11-28	en
dc.date.available	2014-03-14T20:46:46Z	en
dc.date.issued	2001-10-04	en
dc.date.rdate	2004-11-28	en
dc.date.sdate	2001-10-17	en
dc.description.abstract	The ability of a self-contained denitrification system, using fermentation products from waste fish solids, to maintain reliable performance was studied. Denitrification performance was described kinetically and stoichiometrically under different initial nitrate-nitrogen and soluble organic carbon to nitrate-nitrogen ratios. Characterization of soluble organic carbon (measured as soluble chemical oxygen demand, sCOD) indicated that volatile fatty acids (VFA) were generated during the fermentation of the waste fish solids. The results from batch experiments showed that over the range of initial nitrate concentrations studied, complete denitrification was achieved within 6 hrs. sCOD, nitrite, and nitrate profiles across several batch experiments showed that transient nitrite accumulations occurred, but the maximum measured concentrations never completely inhibited nitrate removal. The results suggested that the rate of denitrification was influenced by the initial sCOD to nitrate-nitrogen ratio when transient nitrite concentrations remained below 20 mg/L. However, when nitrite-nitrogen exceeded 25 mg/L, the rate of denitrification was negatively correlated with the maximum measured nitrite-nitrogen concentration. The stoichiometric carbon requirement was not correlated to any parameters believed to influence carbon consumption. After complete denitrification was achieved residual sCOD was still measured, which could not be identified as VFAs. Batch aerobic treatment of denitrified effluent resulted in a 60 to 70 % removal of the residual sCOD when allowed to react for 8 days. It was further determined that the residual sCOD exerted an oxygen of 5.81 on g COD/g C. Additional studies were conducted to maximize sCOD production during fermentation. Increasing the fermentation temperature from 28 oC to 40 oC facilitated a 36 % increase in the specific sCOD production rate (g sCOD/ g fish solids applied). In addition to sCOD production, ammonia production increased 20 % when the fermentation was conducted at the elevated temperature. An analysis comparing the cost of methanol addition to support denitrification to the cost associated with fermenting waste fish solids indicated that supplementing fermentation products with methanol resulted in the least costly strategy for promoting denitrification of an aquaculture waste stream.	en
dc.description.degree	Master of Science	en
dc.identifier.other	etd-10172001-090020	en
dc.identifier.sourceurl	http://scholar.lib.vt.edu/theses/available/etd-10172001-090020/	en
dc.identifier.uri	http://hdl.handle.net/10919/35413	en
dc.publisher	Virginia Tech	en
dc.relation.haspart	brazil3.pdf	en
dc.relation.haspart	brazil2.pdf	en
dc.relation.haspart	brazil1.pdf	en
dc.rights	In Copyright	en
dc.rights.uri	http://rightsstatements.org/vocab/InC/1.0/	en
dc.subject	biological treatment	en
dc.subject	aquaculture	en
dc.subject	fermentation	en
dc.subject	waste solids	en
dc.subject	denitrification	en
dc.title	Evaluation of an Effluent Treatment Strategy to Control Nitrogen From a Recirculating Aquaculture Facility	en
dc.type	Thesis	en
thesis.degree.discipline	Environmental Planning	en
thesis.degree.grantor	Virginia Polytechnic Institute and State University	en
thesis.degree.level	masters	en
thesis.degree.name	Master of Science	en