Evaluation of two start‐up strategies to obtain nitrogen removal via nitrite and examination of the nitrous oxide emissions for different nitritation levels during the treatment of slaughterhouse wastewater

Abstract

BACKGROUND This study investigated the use of a novel start‐up strategy to obtain nitrogen removal via nitrite using real‐time aeration control, in a sequencing batch reactor (SBR1), for the treatment of slaughterhouse wastewater. In addition, another SBR (SBR2) was operated with the same objective, but with a start‐up from seed sludge. Furthermore, analysis of the nitrous oxide (N2O) production and emission was conducted for different nitritation levels. RESULTS Through the absence of an inoculum in SBR1, the nitrifying population could be regulated from the beginning. Beceause of this, nitrite oxidising bacteria could be prevented. This was proved by the nitritation degree (ND) which was already above 80% from day 28, although it took 59 days to achieve sufficient nitrogen removal efficiency (> 80%). In contrast for SBR2, it took 90–110 days to achieve full nitritation, however the nitrogen removal efficiency was above 90% at all times. The maximum N2O emission resulted to be 0.12% of the nitrogen load. CONCLUSION This study suggested the importance of seeding sludge for the achievement of full nitritation. Moreover, a strong positive relationship between the ND and N2O emission was observed. © 2017 Society of Chemical Industry

Biological nutrient removal from slaughterhouse wastewater via nitritation/denitritation using granular sludge: an onsite pilot demonstration

“…These results confirm that NOB could be prevented from the start and nitrogen removal was mainly performed via Nit/DNit. Similarly, Dobbeleers et al . achieved full nitrogen removal after 59 days using a similar startup strategy for the treatment of slaughterhouse wastewater in a lab‐scale SBR.…”

“…The pilot SBR was operated in two operational periods. The aim of period I (P‐I) was to obtain nitrogen removal via Nit/DNit based on the innovative strategy described by Dobbeleers et al . No inoculum was used and the reactor was filled with slaughterhouse wastewater from the full‐scale buffer tank.…”

“…No inoculum was used and the reactor was filled with slaughterhouse wastewater from the full‐scale buffer tank. During the first 8 days of P‐I, an operational strategy similar to that described by Dobbeleers et al . was used.…”

“…Many techniques such as low sludge retention time (SRT), high temperature, free ammonia, low dissolved oxygen and the use of specific inhibitors have been proposed to suppress NOB from an existing microbial population . More recently, Dobbeleers et al . demonstrated full nitritation/denitritation, treating slaughterhouse wastewater, by the use of an innovative startup strategy without seed sludge in combination with aeration phase length control, based on the oxygen uptake rate (OUR), in a lab‐scale sequencing batch reactor (SBR).…”

“…The objectives were twofold: (i) to achieve nitrogen removal via Nit/DNit through the use of an innovative startup strategy without inoculum as described by Dobbeleers et al . ; (ii) the formation of GS performing BNR via Nit/DNit as described by Dobbeleers et al …”