Browsing by Author "Jalalieh, Behnaz Jalili (TTU)"
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Item Impact of free ammonia and free nitrous acid on nitritation in membrane aerated bioreactors fed with high strength nitrogen urine dominated wastewater(2022) Pourbavarsad, Maryam Salehi (TTU); Jalalieh, Behnaz Jalili (TTU); Landes, Nick; Jackson, W. Andrew (TTU)Nitritation can help lower ammonia oxidation treatment costs through traditional nitrogen removal processes for wastewaters with high nitrogen (N) concentrations or low carbon to nitrogen ratios (C/N) and facilitate the anammox process. Free nitrous acid (FNA) or free ammonia (FA) can inhibit nitrite oxidizing bacteria (NOB). Only a few studies have evaluated control of nitritation at elevated TN concentrations and none for TN concentrations > 2000 mg/L, characteristic of confined animal feeding operation (CAFOs) or source separated wastewaters. This study evaluated the factors that promote nitritation in membrane aerated bioreactors (MABRs) treating urine dominated wastewaters (670–4900 mg-N/L) at DO > 3 mg/L and without solids wasting. FNA concentrations > 0.2 mg-N/L and/or FA concentrations > 3 mg-N/L partially inhibit NOB similar to inhibitory concentrations observed in studies for lower strength wastewaters. FNA > 1 mg-N/L completely inhibited NOB. Direct addition of nitrite (NO2-) or pH manipulation to increase either FNA or FA can inhibit even established NOB populations, leading to stable nitritation. For urine dominated wastewaters with TN concentrations > 1000 mg/L or reactors designed to produce an effluent with ~1:1 total ammonia nitrogen (TAN) to NO2- (pre-anammox), all operating regimes (loading or pH) inhibit NOB. These results extend the applications of MABRs to treat high TN concentration, urine dominated wastewaters. MABRs are ideal for remote locations or other applications (off grid communities, CAFOs, underdeveloped countries) that cannot support complex control systems for pH or DO control and eliminate the need for solids processing.Item Nitrogen oxidation and carbon removal from high strength nitrogen habitation wastewater with nitrification in membrane aerated biological reactors(2021) Pourbavarsad, Maryam Saleh (TTU); Jalalieh, Behnaz Jalili (TTU); Harkins, Christian (TTU); Sevanthi, Ritesh (TTU); Jackson, W. Andrew (TTU)Bioreactors for space habitation systems have unique constraints. One type of reactor that could meet these constraints are membrane aerated biological reactors (MABRs). The objective of this work was to establish the performance and optimal loading capacities of multiple MABRs with a variety of habitation waste streams. The MABRs operated over a large range of organic nitrogen (ON) and organic carbon (OC) loading rates (36–220 g/m3-d and 20–200 g/m3-d, respectively) across all wastewaters excluding humidity condensate (HC) where ON and OC loading rates ranged from 1.6 to 11 g/m3-d and 7–55 g/m3-d, respectively. OC and ON transformation rates (29–210 g/m3-d and 23–170 g/m3-d, respectively) were proportional to loading rates and similar to MABRs treating terrestrial high strength wastewaters at similar loadings. MABR maximum loading rates are limited by ON oxidation which controls pH. Above a pH of ~7.8 ON removal is inhibited by free ammonium due to the elevated concentrations of ON in all wastewaters excluding HC. While loading rates are lower than typical terrestrial systems, the MABRs stably operated for up to 5 years with limited maintenance and no solids processing. This work supports the use of MABRs to reliably stabilize habitation wastewaters with minimal consumables. These results also support the use of these MABRs for terrestrial high strength, low volume wastewaters where complex technology may be unsupportable, such as in rural or developing communities with no centralized treatment or for applications where typical two-phase aeration can lead to undesirable off gassing.