Pilot-scale Sequencing Batch Reactor Research Articles

Brain-inspired multimodal approach for effluent quality prediction using wastewater surface images and water quality data

Efficiently predicting effluent quality through data-driven analysis presents a significant advancement for consistent wastewater treatment operations. In this study, we aimed to develop an integrated method for predicting effluent COD and NH3 levels. We employed a 200 L pilot-scale sequencing batch reactor (SBR) to gather multimodal data from urban sewage over 40 d. Then we collected data on critical parameters like COD, DO, pH, NH3, EC, ORP, SS, and water temperature, alongside wastewater surface images, resulting in a data set of approximately 40246 points. Then we proposed a brain-inspired image and temporal fusion model integrated with a CNN-LSTM network (BITF-CL) using this data. This innovative model synergized sewage imagery with water quality data, enhancing prediction accuracy. As a result, the BITF-CL model reduced prediction error by over 23% compared to traditional methods and still performed comparably to conventional techniques even without using DO and SS sensor data. Consequently, this research presents a cost-effective and precise prediction system for sewage treatment, demonstrating the potential of brain-inspired models.

Suppression of nitrite oxidizing bacteria by hydrogen peroxide for energy reduction in municipal wastewater treatment

This paper investigated the application of hydrogen peroxide (H2O2) for achieving partial nitrification in mainstream municipal wastewater treatment process. The investigation was carried out in both bench-scale and pilot-scale sequencing batch reactor systems using primary effluent as feed from municipal wastewater treatment plant. H2O2 played a dual role of: (1) inhibitor for nitrifying microorganisms, and (2) supplemental oxygen source. Bench scale studies were carried out at various doses of initial hydrogen peroxide concentrations (10,25,50,100 mg/L). It was found that at a concentration of 50 mg/L and above ammonia removal reduced by more than 80% implying significant impact on both ammonia oxidizing bacteria (AOB) and nitrite oxidizing bacteria (NOB). After an acclimatization period of 18 days at a dose of 50 mg/L H2O2, complete nitrification was observed with about 30% nitrite accumulation in the effluent which showed NOBs were impacted more significantly than AOBs. It was also observed from the long-term pilot-scale study that the inhibitory impact on NOBs is almost double the impact of on AOBs which facilitated partial nitrification resulting a nitrite accumulation ratio up to 60% in the effluent at 2 mg/L DO and 15 days SRT.Peroxide dosing resulted in an energy savings of 12–15% compared to a control reactor. It was also shown that by reducing the DO from 2 to 1 mg/L, additional power saving of 15% is achievable. Therefore, the proposed approach is an efficient method for aeration energy savings and can be easily implemented in existing wastewater treatment plants.

High-performing enhanced biological phosphorus removal (EBPR) utilizing controlled communities of bacteria in novel biocatalyst composites

Phosphorus pollution is a serious problem for aquatic environments globally. To improve water quality, some regions are implementing stricter discharge limits for phosphorus. Many existing biological technologies cannot reliably achieve new targets due to the complex factors influencing the bacteria responsible for enhanced biological phosphorus removal (EBPR). This study demonstrated robust phosphorus removal from wastewater via EBPR using controlled bacterial communities in hydrophilic polymeric composites, known as MicroNiche Engineered biocatalysts, in bench and pilot-scale sequencing batch reactors, achieving an effluent target of 0.1 mg-P/L as orthophosphate without sludge handling. Metagenomic analysis tracked the taxonomic groups known to contain polyphosphate-accumulating organisms (PAOs), such as Rhodocyclaceae and Comamonadaceae families and the Tetrasphaera, Dechloromonas, and Thauera genera, within the microbial communities contained in the biocatalysts. Findings revealed community compositions differed slightly depending on the starting and operating parameters of the reactor but that PAOs were retained across operational changes.

Pilot Study of Oxic–Anoxic Process under Low Dissolved Oxygen for Nitrogen Removal from Low COD/N Tropical Wastewater

Conventionally, nitrification in biological nitrogen removal (BNR) requires high dissolved oxygen (DO) concentrations (>2 mg L−1), making the process energy intensive. Recent studies have shown that efficient ammonium removal and energy reduction can be realized by operating the nitrification at low DO concentrations (<1 mg L−1). In this study, the low-DO oxic anoxic (low-DO OA) process was operated in a pilot-scale sequencing batch reactor (SBR) over 218 days to evaluate the feasibility of nitrogen removal from low chemical oxygen demand-to-nitrogen ratio (COD/N) tropical municipal wastewater. The results revealed that the low-DO OA process attained high removal efficiency for ammonium (97%) and total nitrogen (TN) (80%) under an average DO concentration of 0.6 mg L−1. The effective TN removal efficiency is attributed to the occurrence of simultaneous nitrification–denitrification (SND) under low DO conditions. Further batch tests revealed that slowly biodegradable COD (sbCOD) in tropical wastewater can support denitrification in the post-anoxic phase, resulting in a high TN removal rate. Compared with high DO concentrations (2 mg L−1), low DO conditions achieved 10% higher TN removal efficiency, with similar ammonium and COD removal efficiency. This study is crucial in promoting the energy efficiency and sustainability of wastewater treatment plants treating low COD/N wastewater.

The knock-on effects of different wastewater feeding modes: Change in microbial communities versus resistance genes in pilot-scale aerobic sludge granulation reactors

To explore the effects of wastewater feeding modes on the formation of aerobic granular sludge (AGS) and the complex relationships between resistance genes and bacteria, two pilot-scale sequencing batch reactors (SBRs) were established. The SBR with influent wastewater introduced uniformly through pipes at bottom was designated as BSBR, and the SBR with inlet wastewater flowing directly from top was TSBR. BSBR formed dense AGS due to uniform wastewater feeding at bottom, while TSBR failed to cultivate AGS. Metagenomic sequencing illustrated that rapid growth of AGS in BSBR was accompanied with increase of antibiotic resistance genes (ARGs) abundance, but ARGs diminished when the size of AGS was stable. The ARGs continued to elevate in TSBR, and abundance of metal resistance genes (MRGs) was always higher than that in BSBR. Two reactors had markedly different bacterial community, microbes in BSBR owned stronger activity, conferred greater potential to proliferate. AdeF in two systems had the most complex gene-bacteria relationships which would undergo HGT within bacterial genus. The different feeding modes of wastewater directly led to the changing size of sludge, which caused knock-on effects of variations in the abundance of microbial communities and resistance genes. This study provided promising suggestions for the rapid cultivation of AGS and control of resistance genes at pilot-scale.

Aerobic granular sludge development using diatomite for low-strength wastewater treatment

This paper presents an assessment of the start-up performance of aerobic granular sludge (AGS) for the treatment of low-strength (chemical oxygen demand, COD < 200mg/L) domestic wastewater by the application of a diatomite carrier. The feasibility was evaluated in terms of the start-up period and stability of the aerobic granules as well as COD and phosphate removal efficiencies. A single pilot-scale sequencing batch reactor (SBR) was used and operated separately for the control granulation and granulation with diatomite. Complete granulation (granulation rate ≥ 90%) was achieved within 20days for the case of diatomite with an average influent COD concentration of 184mg/L. In comparison, control granulation required 85days to accomplish the same feat with a higher average influent COD concentration (253mg/L). The presence of diatomite solidifies the core of the granules and enhances physical stability. AGS with diatomite recorded the strength and sludge volume index of 18 IC and 53mL/g suspended solids (SS) which is superior to control AGS without diatomite (19.3 IC, 81mL/g SS). Quick start-up and achievement of stable granules lead to an efficient COD (89%) and phosphate removal (74%) in 50days of bioreactor operation. Interestingly, this study revealed that diatomite has some special mechanism in enhancing the removal of both COD and phosphate. Also, diatomite has a significant influence on microbial diversity. The result of this research implies that the advanced development of granular sludge by using diatomite can provide promising low-strength wastewater treatment.

Advanced nutrient removal and external sludge reduction: Demonstration in a pilot-scale sequencing batch reactor.

Although the addition of excess sludge fermentation products to improve nutrient removal from sewage is cost-effective, its application has rarely been demonstrated. In this study, the external sludge was first collected and fermented under a sludge retention time of 10days, then introduced into SBR with a 1:15 sewage ratio. The results revealed a gradual increase in the nitrite accumulation ratio to 34.7% in the SBR at the end of the oxic stage after 64 days of adding fermented sludge products. In addition, the average effluent total nitrogen and phosphorous decreased to 7.3 and 0.5mg/L, corresponding to removal efficiencies of 86.7% and 95.5%, respectively. On the other hand, the use of the fermented sludge products as external organic carbon sources in the SBR increased the external sludge reduction ratio to 42.5%. High-throughput sequencing demonstrated that the increase in the endogenous denitrifier community, polyphosphate-accumulating organisms, and fermentation bacteria were the main factors contributing to the increase in nutrient removal and excess sludge reduction. The economic evaluation indicated that the operational cost of the pilot-scale system saves 0.011$/m3 of sewage treated. PRACTITIONER POINTS: Fermented sludge addition effectively enhanced nutrient removal in pilot-scale SBR. Average effluent TN and PO4 3- -P decreased to 7.3 and 0.5 mg/L, respectively. Highest external sludge reduction rate was 42.5% in pilot-scale reactor. Sewage treatment cost can save 0.011$/m3 under advanced nutrient removal.

Comparative Study of Biogas Production from Cassava Pulp in a Sequencing Batch Reactor and a Continuous Stirred Tank Reactor

Thai cassava starch industry generates solid waste or pulp approximately of 9.5 Mt/y (with a moisture content of 70–80%). Biogas production technology has been introduced for several decades in Thailand. However, the implementation of biogas production using cassava pulp as a feedstock is still limited due to the complex lignocellulosic structure, which diminishes hydrolysis. This work investigated biogas production from cassava pulp in a 50-m3 pilot-scale sequencing batch reactor (SBR) and continuous stirred tank reactor (CSTR). Both reactors were fed with cassava pulp, under the organic loading rate (OLR) of 8 kg-COD/m3-d and the average hydraulic retention time (HRT) of 7 d. Under the batch operation, more than 60% of the starch content was utilized within the first three days. The SBR achieved methane production of 1.87 m3-CH4/ton-pulpfresh-d and acids production of 2.19 kg-TVA/ton-pulpfresh-d while the CSTR had methane production of 0.22 m3-CH4/ton-pulpfresh-d and acids production of 7.07 kg-TVA/ton-pulpfresh-d. The methane production was higher in the SBR because the settling process helped microorganisms remain in the system. In CSTR, acids rather than methane were produced due to the washout of methanogenic microorganisms. This work revealed that the SBR yielded higher biogas production, while the CSTR produced intermediate acids, which could be supplied to the biochemical industry.

How can the addition of extracellular polymeric substances (EPS)-based bioflocculant affect aerobic granular sludge (AGS)?

The ability of extracellular polymeric substances (EPS) recovered from aerobic granular sludge (AGS) to act as bioflocculant was tested in a pilot-scale sequencing batch reactor (SBR), fed with low-strength municipal wastewater. EPS were compared with the addition of Na-alginate as a standardized biopolymer. The optimal dosage of both biopolymers was determined through jar-test assays (400 mg L−1 of Na-alginate in a 250 mg Ca L−1 and 50 mg L−1 of EPS in pH of 2 ± 0.2). The addition of Na-alginate (Operational Period I– OP–I) and EPS (Operational Period II - OP-II) led to increased adhesion of particles with 2.9 ± 0.45 and 1.3 ± 0.3 g TSS L−1 during OP-I and OP-II, respectively, and fast settling biomass (SVI30 between 68 and 78 mL g−1). Granule predominance occurred at early stages of OP-I (day 37) and OP-II (day 44), presenting diameters mainly within the 212–600 μm range. The reactor showed removal efficiencies of 85% for biochemical oxygen demand (BOD) and above 50% for N–NH4 during the study periods. Furthermore, the addition of EPS as a bioflocculant promoted a substantial increase in polysaccharides (PS = 153.01 ± 121 mg gVSS−1) and proteins (PN = 121.96 ± 69 mg gVSS−1), while the addition of Na-alginate affected mostly the PS content (87 ± 24 mg gVSS−1). The microbial community shifted mainly from Betaproteobacteria (45%) during OP-I to Alphaproteobacteria (64%) in OP-II. Therefore, EPS affected both physical-chemical and microbial features of the AGS biomass without any change in treatment efficiencies. EPS is a promising resource to be recovered from aerobic granular sludge and to be used as an alternative and sustainable bioflocculant.

Assessment of Nitrous Oxide and Carbon Dioxide Emissions and the Carbon Footprint in an Aerobic Granular Sludge Reactor Treating Domestic Wastewater

The assessment of nitrous oxide (N2O) and carbon dioxide (CO2) emissions from wastewater treatment processes using aerobic granular biomass is still scarce and most of them deal with synthetic wastewater in well-controlled conditions. Also, the greenhouse gases footprint from aerobic granular process has been poorly described despite a strong impact on climate change. This work quantified and analyzed the N2O and CO2 emissions, as well as the treatment efficiency of a pilot-scale sequencing batch reactor with aerobic granular sludge (AGS) fed with real domestic wastewater. The operational conditions applied to the reactor allowed the development of AGS (1.7 ± 0.40 gVSS/L), with good settleability (SVI30 < 50 mL/g) and removal efficiencies of 84% for BOD5 and 65% for NH4+-N. The relative amount of nitrogen denitrified to N2O was 22.9%, which corresponded to an emission factor of 5.67% ± 1.68%. The contribution of N2O emitted through the gas phase was 97.1%, with a flow-based emission factor of 3.65 × 10−3 g N2O-N/L, while the contribution of N2O released through the liquid phase was 2.9%, with a flow-based release factor of 0.11 × 10−3 g N2O-N/L. Although CO2 flow-based emission factor was higher (0.297 g CO2/L), in terms of carbon footprint, the global warming impact of N2O was five times higher than the impact of CO2 emissions ( of 83.6% and of 16.4%).

Microbial community and performance of a partial nitritation/anammox sequencing batch reactor treating textile wastewater

Implementation of onsite bioremediation technologies is essential for textile industries due to rising concerns in terms of water resources and quality. Partial nitritation-anaerobic ammonium oxidation (PN/A) processes emerged as a valid, but unexplored, solution. In this study, the performance of a PN/A pilot-scale (9 m3) sequencing batch reactor treating digital textile printing wastewater (10–40 m3 d−1) was monitored by computing nitrogen (N) removal rate and efficiencies. Moreover, the structure of the bacterial community was assessed by next generation sequencing and quantitative polymerase chain reaction (qPCR) analyses of several genes, which are involved in the N cycle. Although anaerobic ammonium oxidation activity was inhibited and denitrification occurred, N removal rate increased from 16 to 61 mg N g VSS−1 d−1 reaching satisfactory removal efficiency (up to 70%). Ammonium (18–70 mg L−1) and nitrite (16–82 mg L−1) were detected in the effluent demonstrating an unbalance between the aerobic and anaerobic ammonia oxidation activity, while constant organic N was attributed to recalcitrant azo dyes. Ratio between nitrification and anammox genes remained stable reflecting a constant ammonia oxidation activity. A prevalence of ammonium oxidizing bacteria and denitrifiers suggested the presence of alternative pathways. PN/A resulted a promising cost-effective alternative for textile wastewater N treatment as shown by the technical-economic assessment. However, operational conditions and design need further tailoring to promote the activity of the anammox bacteria.

Robustness of mainstream anammox activity at bench and pilot scale

New technologies and processes, such as mainstream anammox, aim to reduce energy requirements of wastewater treatment and improve effluent quality. However, in municipal wastewater (MWW) anammox system are often unstable due to process control disturbance, influent variability, or unwanted nitrite oxidizing bacteria (NOB). This study examines the anammox system by focusing on anammox activity and its robustness in a mainstream environment. An 8 m3 pilot-scale sequencing batch reactor (SBR) receiving pretreated MWW (with external nitrite addition) was seeded with pre-colonized carriers. Within six months at 12–20 °C an anammox activity of 200 gN·m−3·d−1 was achieved. After the startup an anammox activity of 260 ± 83 gN·m−3·d−1 was maintained over 450 days. The robustness of the anammox activity was analyzed through three disturbance experiments. Anammox biofilm on carriers were exposed to dissolved oxygen (DO = 1.6 mg·L−1, intermittent aeration), organic loading rate (OLR, C/N increased from 2:1 to 5:1) and temperature disturbances (20 °C to 12 °C) in triplicate 12 L bench scale reactors. The anammox activity and microbial community was monitored during these disturbances. The DO and OLR disturbance experiments were replicated at pilot scale to investigate upscaling effects. Bench and pilot scale anammox activity were unaffected by the DO disturbance. Similarly, an increase in OLR did not deteriorate the bench and pilot scale anammox activity, if nitrate was available. When, at bench scale, the reactor temperature was reduced from 20 °C to 12 °C overnight, anammox activity decreased significantly, this was not the case for the slow seasonal temperature changes (12–25 °C) at pilot scale where no strong temperature dependency was detected in winter. Metagenomic analysis revealed a broad range of Brocadiaceae species with no single dominant anammox species. Anammox thrive under mainstream conditions and can withstand typical process disruptions.

Features of aerobic granular sludge formation treating fluctuating industrial saline wastewater at pilot scale

A pilot-scale sequencing batch reactor, with a working volume of 3 m3, was installed in a fish cannery to develop aerobic granular sludge treating the produced effluents. Depending on the nitrogen (N) and organic matter (COD) concentration, the effluents were named in this study as medium-low-strength (Stage I) and high-strength (Stage II) wastewater. The composition of the wastewater was found to be a crucial factor to select granule-forming organisms. With medium-low-strength wastewater as feeding, the first granules were observed after 30 days, but the extremely high COD/N ratios of the wastewater provoked the overgrowth of filamentous bacteria after 4 months of operation (Stage I). When treating high-strength wastewater, stable aggregates with good settleability appeared, but well-shaped granules were not observed since the granulation process was not completed. The system was able to remove both COD (70–95%) and N (30–90%) treating both types of effluents. Biomass growth was the main N removal pathway. The reactor was found to be robust against factory production stops and, thus, a suitable alternative to treat wastewater from industries with discontinuous operation.

Recovery of nitrogen removal by N2H4 after nitrite inhibited anammox reaction

&lt;p&gt;A pilot-scale sequencing batch reactor (SBR) for anaerobic ammonium oxidation (anammox) of bacteria culture was used along with a batch experimental reaction device to study the effect of NO2--N concentration on the activity of anammox bacteria and the recovery of N2H4 on anammox bacteria after inhibition by high concentrations of NO2--N. The optimal influent NO2--N concentration in the pilot-scale reactor was 72.0 mg/L, with its total nitrogen consumption being approximately 40.0 g/d. Influent water NO2--N concentrations greater than 100 mg/L had a serious inhibitory effect on the anammox bacteria. At an influent NO2--N concentration of 120.35 mg/L, the addition of 10.0-15.0 mg/L of N2H4, restored the activity of granular anammox bacteria; the total nitrogen consumption was increased by 69.96%. Microbiological analysis showed that a change in NO2--N concentration within the range of 18.87-115.39 mg/L did not affect the microbial population structure of the pilot-scale reactor, wherein Candidatus Kuenenia was the dominant bacterial species. In samples collected at stages A0 (sludge inoculation), A20 (the number indicates the NO2--N concentration, which, in this stage, was 20 mg/L), A40, A60, A80, and A100, the proportion of Candidatus Kuenenia was 27%, 23%, 36%, 26%, 34%, and 33%, respectively.&lt;/p&gt;&#x0D;

A Bioreactor Designed for Restricting Oversize of Aerobic Granular Sludge

Aerobic granular sludge (AGS) with oversized diameter commonly affects its stability and pollutant removal. In order to effectively restrict the particle size of AGS, a sequencing batch reactor (SBR) with a spiny aeration device was put forward. A conventional SBR (R1) and an SBR (R2) with the spiny aeration device treating tannery wastewater were compared in the laboratory. The result indicates that the size of the granular sludge from R2 was smaller than that from R1 with sludge granulation. The spines and air bubbles could effectively restrict the particle size of AGS by collision and abrasion. Nevertheless, there was no significant change in mixed liquor suspended solids (MLSS) and the sludge volume index (SVI) in either bioreactors. The removal (%) of chemical oxygen demand (COD) and ammonia nitrogen (NH4+-N) in these two bioreactors did not differ from each other greatly. The analysis of biological composition displays that the proportion of Proteobacteria decreased slightly in R2. The X-ray fluorescence (XRF) analysis revealed less accumulation of Fe and Ca in smaller granules. Furthermore, a pilot-scale SBR with a spiny aeration device was successfully utilized to restrict the diameter of granules at about 300 μm.

Waste nutrient solutions from full-scale open hydroponic cultivation: Dynamics of effluent quality and removal of nitrogen and phosphorus using a pilot-scale sequencing batch reactor

Hydroponic cultivation is revolutionizing agricultural crop production techniques all over the world owing to its minimal environmental footprint, enhanced pest control, and high crop yield. However, waste nutrient solutions (WNS) generated from hydroponic systems contain high concentrations of N and P; moreover, they are discharged into surface and subsurface environments, leading to eutrophication and subsequent ecosystem degradation. In this study, the nutrient concentrations in WNS from 10 hydroponic indoor tomato, capsicum, and strawberry farms (greenhouses) were monitored for up to six months. The concentrations of N and P in WNS discharged from these farms were 48.0–494.0 mg L−1 and 12.7–96.9 mg L−1, respectively, which exceeded the Korean water quality guidelines (40.0 mg L−1 N and 4.0 mg L−1 P) for effluents. These concentrations were varied and dependent on the supplied nutrient concentrations, crop types, and growth stages. In general, the concentrations of N and P were in the following order: tomato > capsicum > strawberry. High N as NO3− and P as PO43− but low organic C in WNS warrant subsequent treatment before discharge. Therefore, this study tested a pilot-scale sequencing batch reactor (SBR) system as a potential technology for WNS treatment. The SBR system had BOD, COD, nitrate, and phosphate removal efficiency of 100, 100, 89.5, and 99.8%, respectively. In addition, the SBR system removed other cations such as Ca2+, dissolved Fe, K+, Mg2+, and Na+ and the removal efficiencies of those ions were 48, 67, 18, 14 and 15%, respectively. Lower methanol addition (0.63 mg L−1) and extended aeration (~30 min) improved SBR performance efficiency of C, N, and P removal. Thus, SBR showed significant promise as a treatment alternative to WNS pollutants originating from hydroponic systems.

Evaluation of sequencing batch bioreactor followed by media filtration for organic carbon and nitrogen removal in produced water

Produced water contains high concentrations of total dissolved solids (TDS), metals, and organic matter. In areas of high water stress, beneficial reuse of produced water needs to be considered. This study evaluates the treatment capabilities, efficiency, and limitations of a sequencing batch reactor (SBR) to remove organic material and nutrients from produced water. SBRs have been used to facilitate biological organic and nutrient removal from municipal and industrial waste streams. Although the bacteria responsible for the treatment of municipal and most industrial wastewaters cannot tolerate the high TDS concentrations in produced water, the microorganisms native to produced water have the capacity to treat produced water. In a bench scale bioreactor test using produced water from the Denver-Julesburg Basin, the produced water was determined to be nutrient limited with respect to phosphorus. By adding a phosphorus supplement, soluble chemical oxygen demand (COD) removal was increased by over 20 % and ammonia removal increased by approximately 40 %. Various supplements, including KH2PO4, centrate from an anaerobic digester, and activated sludge from a municipal SBR, were added to the bioreactors to determine which of them was more effective. A pilot scale SBR followed by media filtration was used to evaluate the effects of operating conditions on produced water treatment. The hydraulic residence time ranged from 1.67 to 8.3 days during various phases of operation, with no measured effect on treatment performance. Adding 7.5 mg-P/L of KH2PO4 as a phosphorus supplement had the most significant effect on treatment performance of the system. The majority of COD removal switched locations from the filter columns to the bioreactors. Comparing total organic carbon to COD, the biologically available portion of COD appears to be treated in the SBR while recalcitrant carbon and inorganic material may need to be removed via physical or chemical methods.

The effect of Np-magnetite on the granulation process of an SBR reactor used for domestic wastewater treatment.

This study investigated the effect of magnetite nanoparticles (Np-magnetite) added to a pilot-scale sequencing batch reactor (SBR) treating domestic wastewater, to improve aerobic granular sludge (AGS) formation and the effects of granule disintegration. Np-magnetite additions (75mg L-1) were made during the start-up of the reactor and repeated after 100 and 170days, when granule disintegration was observed. From the first Np-magnetite addition, SVI5 was reduced from 1315 to 85mLg-1. The granular biomass was observed on the 56th day, when 57% of the granules presented diameters bigger than 212µm. The 100-day disintegration episode disturbed the granular biomass, reducing the volatile suspended solids by 51%, increasing the SVI values to above 200mLg-1. Np-magnetite addition recovered all the granular biomass parameters to the values observed before disintegration. The treatment efficiency was stable during operation of the reactor for nutrients (52.8 ± 23.4% NH4+-N; 54.5 ± 12.2% PO43--P) and carbonaceous organic matter (71.7 ± 12.7% BOD5; 77.5 ± 10.0% CODt). Np-magnetite addition changed the microbial community of the granular sludge, analysed via high-throughput 16S RNA sequencing, and recovered the treatment efficiency previously disturbed by the disintegration processes. These results indicate the potential of Np-magnetite as an agent for sludge aggregation in an aerobic granular reactor.

Innovative start-up strategies for single-stage deammonification with conventional activated sludge: Results of a pilot-scale demonstration

This study investigated innovative start-up strategies of a pilot-scale sequencing batch reactor (SBR) for single-stage deammonification using activated sludge as the sole inoculum source. In 24 m3 aerobic oxidizing bacteria cultivation plant, nitrogen loss efficiency was suggested to be an indicator for determining duration of cultivation. In 12 m3 ANAMMOX (ANaerobic AMMonium OXidation) cultivation plant, combined strategy (sequential fed-batch and continuous modes) was adopted to promote ANAMMOX activity from activated sludge. Both the cultivated sludge were inoculated in 24 m3 pilot-plant for single-stage SBR with deammonification. The feed distribution strategy was used to cultivate ANAMMOX bacteria selectively resulting in nitrogen removal rate of 0.73 kg/m3/d and nitrogen removal efficiency of 86.5 ± 1.9% within 254 days. Candidatus Brocadia sp. 40 was enriched from undetectable to 22.7% relative abundance. These findings indicated that fast start-up of the deammonification process was possible without ANAMMOX seed sludge in pilot-scale reactor with various variables.

Suitability of SBR for Wastewater Treatment and Reuse: Pilot-Scale Reactor Operated in Different Anoxic Conditions.

The present study investigates the performance of a pilot-scale Sequencing Batch Reactor (SBR) process for the treatment of wastewater quality parameters, including turbidity, total suspended solids (TSS), total solids (TS), nitrogen (ammonia (NH3–N), nitrite (NO2−), and nitrate (NO3−), phosphate (PO43−), the chemical oxygen demand (COD), and the 5-day biological oxygen demand (BOD5), from municipal wastewater. Two scenarios, namely, pre-anoxic denitrification and post-anoxic denitrification, were investigated to examine the performance of a pilot-scale SBR on the wastewater quality parameters, particularly the nitrogen removal. The correlation statistic was applied to explain the effects of operational parameters on the performance of the SBR system. The results revealed that the post-anoxic denitrification scenario was more efficient for higher qualify effluent than the first scenario. The effluent concentrations of the targeted wastewater quality parameters obtained for the proposed SBR system were below those of the local standards, while its performance was better than that of the North Sewage Treatment Plant, Dharan, Eastern province, Kingdom of Saudi Arabia (KSA), in terms of the BOD5, COD, TN, and PO43- treatment efficiencies. These results indicated the suitability of SBR technology for wastewater treatment in remote areas in the KSA, with a high potential of reusability for sustainable wastewater management.