Development and examination of a granular nitrogen-fixing wastewater treatment system

Enrichment of anodophilic nitrogen fixing bacteria in a bioelectrochemical system

“…Industrial wastewaters, including wastewater produced from pulp and paper industries, are carbon (C) rich but nitrogen (N) deficient (Pratt et al, 2007;Pokhrel and Viraraghavan, 2004). To enable efficient biological treatment, a C:N ratio of 100:5 in the raw influent is usually recommended (Peng et al, 2003;Slade et al, 2011).…”

“…As an alternative to supplementing N, the use of diazotrophic (N 2 -fixing) bacteria has been proposed as a method for treating N-deficient wastewater in activated sludge systems (Pratt et al, 2007;Gauthier et al, 2000). N 2 -fixing bacteria are capable of converting atmospheric nitrogen (N 2 ) to ammonia (NH 3 ) as a means of supplementing N requirements for growth (Nair, 2010).…”

Characterization of aerobic granular sludge at various organic loading rates

“…Furthermore the granulation system could operate at high OLRs up to 15 kg COD/m 3 d [2]. Several researchers investigated aerobic granule formation from activated sludge [3][4][5][6]. However, studies on formation and characteristics of aerobic granule with supports are very limited.…”

Bacterial nitrogen fixation in sand bioreactors treating winery wastewater with a high carbon to nitrogen ratio

“…More recently, it was shown that NF occurred at the anode of a bioelectrical system fed with glucose (Wong et al, 2014). Apart from the obvious cost and labour savings, a major advantage of these self-regulating systems over those where exogenous N is added, is that the final effluent N concentrations are low and stable (Clark et al, 1999;Pratt et al, 2007). In addition, granular morphology, sludge settleability, and dewater-ability may be improved, as demonstrated in laboratory scale sequencing batch reactors (Clark et al, 1999;Pratt et al, 2007).…”

“…Apart from the obvious cost and labour savings, a major advantage of these self-regulating systems over those where exogenous N is added, is that the final effluent N concentrations are low and stable (Clark et al, 1999;Pratt et al, 2007). In addition, granular morphology, sludge settleability, and dewater-ability may be improved, as demonstrated in laboratory scale sequencing batch reactors (Clark et al, 1999;Pratt et al, 2007). Despite the fact that nitrogenases are sensitive to oxygen, it has been established that high dissolved oxygen concentrations created via aeration do not negatively affect the functional NF population (Pratt et al, 2007;Slade et al, 2003).…”