High rate simultaneous nutrients removal in a single air lift bioreactor with continuous feed and intermittent discharge regime: Process optimization and effect of feed characteristics

Abstract

In this research, continuous feed and intermittent discharge air lift bioreactor (CFIDAB) was evaluated under two independent variables to treat milk processing wastewater (MPW). The effect of HRT (6-14 h) and air flow rate (1-3 l/min) on the performance of CFIDAB was studied in a laboratory scale of the bioreactor. The optimum values of HRT and air flow rate were 10 h and 3 l/min, reaching SCOD, TN, and TP removal efficiency around 98, 85, and 78%, respectively. The results showed that TP and TN removal were enhanced simultaneously with an increase in HRT and air flow rate. Oxidation-reduction potential (ORP) measurement at the optimal condition showed the successful occurrence of anaerobic, anoxic, and aerobic zones in the CFIDAB. Moreover, the effect of feed characteristics on the process performance for milk processing and soft drink wastewaters was investigated. Based on the obtained data, CFDIAB operated with soft drink wastewater (SDW) showed a better performance in removal of carbon and phosphorus compounds, while nitrogen content was removed more efficient for MPW. As a result, the performance of CFIDAB is sensitive to BOD 5 /COD ratio of wastewater. Overall, this single compartment airlift bioreactor could act as an efficient biological nutrient removal system, providing the conditions for good carbon and nutrient removal. It showed an excellent reactor geometry as well as operating strategy to be used as a membrane bioreactor.

Moving bed membrane bioreactors for carbon and nutrient removal: The effect of C/N variation

“…The key compounds required to characterize samples were measured according to the Standard Methods [23]; e.g., TSS, volatile suspended solids (VSS), supernatant and total COD (COD SUP and COD TOT , respectively); NH 4 N, NO 2 N, NO 3 N, total nitrogen (TN), PO 4 -P and total phosphorus (TP). Free ammonia (FA, NH 3 ) was also evaluated as proposed by Hansen et al [24].…”

“…BNR processes usually rely on a combination of different environmental conditions (anaerobic, anoxic and aerobic) inside separate compartments [4]. Briefly, the N and P removal in BNR processes is usually accomplished by heterotrophic organisms able to denitrify and to accumulate polyphosphate (phosphorus accumulating organisms − PAOs) [5].…”

Integrated Fixed Film Activated Sludge (IFAS) membrane BioReactor: The influence of the operational parameters

“…Compared to the chemical nutrients removal, BNR treatments avoids chemical addition and the consequent production of chemical sludge, difficult to manage compared to the biological sludge (among others, Mannina et al, 2016a,b). Nutrients removal in such systems can be obtained by means of diverse in series conditions (i.e., anaerobic, anoxic and aerobic) (Ekama et al, 1983;Xu et al, 2014;Asadi et al, 2016). The biological N removal can be obtained by means of a two-step process: the first one being the ammonia oxidation to nitrites and nitrates achieved by autotrophic bacteria under aerobic conditions (nitrification); the second one is the reductive process of nitrates under anoxic conditions carried out by heterotrophic bacteria (heterotrophic denitrification) (Xu et al, 2014).…”

Efficiency of wastewater treatment in hybrid barbotage reactors with moving beds

“…In each design variant of ARL reactors, we may distinguish four hydrodynamic zones: lifting, degassing, fall, and bottom [1]. ALRs are considered an alternative to stirred tank reactors (STR), particularly in the case of such numerous bioprocesses as plant and animal cell cultures, but also as a solution to purify streams of contaminated fluids (sewage, exhaust gases) [2][3][4][5]. Industrial applications of ALRs have been limited due to a lack of certain data required for their appropriate design, construction, operation, and scaling, as well as reliable models and empirical correlations capable of predicting key operating parameters in various ALR design variants and operating conditions.…”