A sequencing batch reactor system for high-level biological nitrogen and phosphorus removal from abattoir wastewater

Abstract

A sequencing batch reactor (SBR) system is demonstrated to biologically remove nitrogen, phosphorus and chemical oxygen demand (COD) to very low levels from abattoir wastewater. Each 6 h cycle contained three anoxic/anaerobic and aerobic sub-cycles with wastewater fed at the beginning of each anoxic/anaerobic period. The step-feed strategy was applied to avoid high-level build-up of nitrate or nitrite during nitrification, and therefore to facilitate the creation of anaerobic conditions required for biological phosphorus removal. A high degree removal of total phosphorus (>98%), total nitrogen (>97%) and total COD (>95%) was consistently and reliably achieved after a 3-month start-up period. The concentrations of total phosphate and inorganic nitrogen in the effluent were consistently lower than 0.2 mg P l(-1) and 8 mg N l(-1), respectively. Fluorescence in situ hybridization revealed that the sludge was enriched in Accumulibacter spp. (20-40%), a known polyphosphate accumulating organism, whereas the known glycogen accumulating organisms were almost absent. The SBR received two streams of abattoir wastewater, namely the effluent from a full-scale anaerobic pond (75%) and the effluent from a lab-scale high-rate pre-fermentor (25%), both receiving raw abattoir wastewater as feed. The pond effluent contained approximately 250 mg N l(-1) total nitrogen and 40 mg P l(-1) of total phosphorus, but relatively low levels of soluble COD (around 500 mg l(-1)). The high-rate lab-scale pre-fermentor, operated at 37 degrees C and with a sludge retention time of 1 day, proved to be a cheap and effective method for providing supplementary volatile fatty acids allowing for high-degree of biological nutrient removal from abattoir wastewater.

Slaughterhouse wastewater characteristics, treatment, and management in the meat processing industry: A review on trends and advances

“…Overall efficiencies were achieved for COD and TN in the range 95e96% and 95e97%, respectively. Likewise, Lemaire et al (2008Lemaire et al ( , 2009) evaluated the performance of SBRs under 6 h cycles for SWW treatment. High efficiencies for COD, TP, and TN removal of 95, 98, and 97% were achieved, respectively.…”

Operational strategies for nitrogen removal in granular sequencing batch reactor

“…In addition, it allows nitrification to occur at a lower organic loading in the aerobic phase, which accelerates nitrification rate and saves aeration consumption to oxidize organic matters in influent. Some studies have been documented on alternating aerobic/anoxic and step-feed mode in activated sludge system [21][22][23][24][25][26], which shows that it is both technologically and economically effective in enhancing nitrogen removal efficiency. With more compact structure and bigger size than activated sludge, whether granular sludge can achieve effective nitrogen removal under this operational strategy is to be investigated.…”

A tecnologia de remoção de fósforo: gerenciamento do elemento em resíduos industriais

“…Esses sistemas têm sido empregados eficientemente em escala industrial no tratamento de esgotos domésticos além de diversas águas residuárias industriais, com eficiências de remoção variando entre 75 a 99%, em uma faixa de carga de fósforo total de 25mgL -1 a 125mgL -1 (Lemaire et al, 2009;Mulkerrins et al, 2004;Kishida et al, 2009).…”