Wastewater Nutrient Removal Research Articles

Systematic Evaluation of Emerging Wastewater Nutrient Removal and Recovery Technologies to Inform Practice and Advance Resource Efficiency

Advancing nutrient recovery from idea to implementation requires reporting practices that facilitate comparison among diverse nutrient removal and recovery (NRR) technologies and enhance the transl...

Effects of flashing light–emitting diodes (LEDs) on membrane fouling in a reciprocal membrane photobioreactor (RMPBR) to assess nitrate and phosphate removal from whey wastewater

Light is one of the most critical factors for the growth of microalgae; therefore, optimization and accessibility of light improve productivity and wastewater nutrient removal is important. The flashing light effect allows microalgae to use light effectively through intermittent exposure. Nutrient assimilation and membrane fouling were considered in a reciprocal membrane photobioreactor (RMPBR) and an LED flashing light was provided as a source of illumination. The objective of this study was to bridge the gap between light delivery and RMPBR performance. In this connection, we examined flashing lights with frequencies of 1 Hz and 1000 Hz at a constant duty cycle of 60% along with continuous light. Regarding the effect of the flashing light on RMPBR, the cells which acclimated to flashing light of 1000 Hz resulted in maximum removal of nitrate (97%) and phosphate (70%). However, the culture with the low frequency of 1 Hz was only able to remove nitrate and phosphate up to 68% and 47%, respectively. Furthermore, the reactor with 1-Hz flashing light frequency was fouled earlier within 84 h thereby reaching the highest pore-blocking. Proteins and carbohydrates were recognized as a major cause of fouling in the low-frequency flashing light. We conclude that high-frequency flashing light (1000 Hz) could be an effective light condition for nutrient uptake in wastewater treatment.

Identification of a microalgae-yeast coculture system for nutrient removal in shrimp culture wastewater

The accumulation of nitrogen and phosphorous has detrimental effects on aquatic animals and negatively influences the economic benefits of aquaculture; thus, the control of water quality is of significance for the development of the aquaculture industry. In this study, a coculture system of Chlorella vulgaris + Rhodosporidium sphaerocarpum exhibited superior nitrogen removal performances compared with those of either the Isochrysis galbana + R. sphaerocarpum or the Tetraselmis helgolandica + R. sphaerocarpum coculture systems. The alginate-immobilized C. vulgaris and suspended R. sphaerocarpum coculture system was advantageous in terms of nutrient removal and the inoculum ratio (IR, dry weight of C. vulgaris to dry weight of R. sphaerocarpum) of 5:1 was determined to yield optimal removal performances of nutrients and the chemical oxygen demand (COD), with which 86.20% of the NH4+ content was removed, and 100.00% removal efficiency of NO2−, NO3−, PO43−, and COD was detected after 120 h of incubation. The growth of C. vulgaris and R. sphaerocarpum was enhanced and a biomass productivity of 0.22 g L−1 day−1 was obtained. The sustainability of the optimized microalgae-yeast coculture system was confirmed by steady and consistent removal performances in semicontinuous experiments, removing over 80% of NH4+, 100% of NO3−, and over 90% of NO2−, PO43−, and COD. These results indicated that the optimized microalgae-yeast coculture system developed in our studies might provide a potential method for the biological treatment of aquaculture wastewater.

Estimation of greenhouse gas and odour emissions from a cold region municipal biological nutrient removal wastewater treatment plant

Seasonal temperature variations in cold regions worldwide lead to variable gas emissions from municipal wastewater treatment plants (MWTPs) due to changing wastewater temperatures in open-to-air treatment processes. The objective of this study was to determine the greenhouse gas (including carbon dioxide, CO2; methane, CH4; and nitrous oxide, N2O) and odour (including ammonia, NH3; and hydrogen sulphide, H2S) emission rate estimates (EREs) from the open-to-air processes of a biological nutrient removal (BNR) type MWTP in Saskatoon, SK, Canada. This MWTP experiences seasonal temperatures from −40 °C to 30 °C with the resultant wastewater temperatures considered herein of 13 °C and 17 °C being chosen based on monitoring data for winter and summer, respectively. Laboratory-scale reactors simulating anaerobic, anoxic, aerobic, and settling treatment processes were used to monitor gas EREs using wastewater samples taken from the analogous MWTP processes during the winter and summer seasons. Results indicated that the overall winter EREs for CO2, CH4, and N2O were 45,129 kg CO2/d, 21.9 kg CH4/d, and 3.20 kg N2O/d, respectively, while the H2S EREs were insignificant. The higher temperature for the summer samples resulted in increased EREs for CH4, N2O, and H2S EREs of 33.0 kg CH4/d, 3.87 kg N2O/d, and 2.29 kg H2S/d, respectively. However, the CO2 EREs were reduced to 37,794 kg CO2/d. Overall, the aerobic reactor was the dominant source of the GHG emissions for both seasons. In addition, studied changes in the aerobic reactor aeration rates (in reactor) and BNR treatment configurations (from site) further impacted the EREs.

Microalgae production using photo-bioreactor with intermittent aeration for municipal wastewater substrate and nutrient removal

Microalgae has emerged as a promising approach for removing substrate and nutrient from wastewater with the concomitant biofuel production. The substrate and nutrient removal are influenced by several factors such as C/N ratio, F/M ratio, pH, and DO. This study aims to determine the efficiency of substrate and nutrient removal with the growth rates of microalgae and biomass by varying the addition of aeration and substrate. Intermittently aerated reactors were used with the flow rate of 14 L/minute. The batch reactors were prepared by adding glucose substrate of 50 mg/L (Ra0A), 100 mg/L (Ra0B), and 150 mg/L (Ra0C) without aeration; 50 mg/L (Ra12A), 100 mg/L (Ra12B), and 150 mg/L (Ra12C) with 12-hour aeration, and 50 mg/L (Ra24A), 100 mg/L (Ra24B), and 150 mg/L (Ra24C) with 24-hour aeration. The substrate removal, expressed as chemical oxygen demand (COD) in the reactor with aeration, showed the efficiency of 73.88% ± 2.05 (12-hour aeration), 75.2% ± 3.97 (24hours aeration), and 69.86% ± 5.69(without aeration). Nutrient removal as ammonia-N (NH3-N) gave high removal value of 98.3% ± 0.11 and the removal of nutrient as phosphate (PO3-4) showed the efficiency of 54.3% ± 0.1. The growth rate of microalgae and biomass exhibited the highest value in Ra24C reactor with the values ??of 0.0229/day and 0.1295/day, respectively. The pH values ??indicated a shift from normal to alkaline while DO values ??increased by the addition of 12 and 24-hour aeration.

Enhanced Microalgae Growth for Biodiesel Production and Nutrients Removal in Raw Swine Wastewater by Carbon Sources Supplementation

In the present work, effect of two carbon sources, namely, sodium bicarbonate and sodium acetate, on the growth of Spirulina platensis, raw swine wastewater (RSW) nutrients removal, and lipid production efficiency was thoroughly investigated. Experimental results showed that maximum biomass concentration and total nitrogen (TN), total phosphorous (TP), and ammonium removal percentage of 1.70 g L−1, 91.24%, 87.44%, 100% were achieved, respectively, when sodium bicarbonate was supplemented to the RSW, which were significantly (p < 0.05) higher than that of the control. With regard to sodium acetate as extra carbon source, maximum biomass concentration and TN, TP, and ammonium removal percentage reached 2.18 g L−1, 85.72%, 87.02%, and 100%, respectively, which were notably enhanced compared to that of the control. Furthermore, saturated fatty acids and unsaturated fatty acids content in the obtained biomass ranged from 68.01–69.44% to 30.56–31.99%, respectively, and hexadecanoic acid, palmitoleic acid, octadecenoic acid and linoleic acid were found to be the major fatty acid components in the algal lipids. Thus, sodium bicarbonate and sodium acetate supplementation to RSW are technically feasible strategies to enhance Spirulina platensis growth for simultaneously nutrients removal and biodiesel production.

Abatement of circumneutral mine drainage by Co-treatment with secondary municipal wastewater

Acid mine drainage is a persistent and problematic source of water pollution. Co-treatment with municipal wastewater at existing wastewater treatment plants has several advantages; however, potential impacts on plant physicochemical and biological processes have not been well explored. The primary purpose of this bench-scale study was to examine the impact of co-treatment by combining a mild acid mine drainage at various ratios with municipal wastewater, followed by sludge settling and supernatant comparative analysis using a variety of effluent water quality parameters. These measurements were combined with carbonate system and adsorption isotherm modeling to elucidate the mechanisms underlying the experimental results. Acid mine drainage addition decreased municipal wastewater effluent PO43− concentrations below 0.2 mg/L with greater than 97% removal, demonstrating co-treatment as an alternative solution for municipal wastewater nutrient removal. Biochemical oxygen demand remained similar to controls with <10% variation after co-treatment. Coagulation from metals in acid mine drainage was incomplete due to PO43− adsorption, confirmed by comparing experimental results with Langmuir isotherm behavior. Sweep flocculation was the dominating particle aggregation mechanism, and co-treatment led to improved particle clarification outcomes. Improved clarification led to up to 50% Fe removal. Final pH had little variation with all conditions having pH > 6.0. Carbonate system modeling adequately explains pH effects, and can also be applied to varying acid mine drainage matrices. The impact of acid mine drainage addition on the municipal wastewater microbial community was also investigated which provided evidence of microbial adaptation. This study demonstrates post-aeration co-treatment enables mitigation of mild acid mine drainage without adversely affecting wastewater treatment plant processes. Reported results also frame required future studies to address extant questions prior to full-scale adaptation.

Identification of Transformation Products for Benzotriazole, Triclosan, and Trimethoprim by Aerobic and Anoxic-Activated Sludge

This study identified biotransformation products formed from three anthropogenic trace organic compounds (TOrCs) (benzotriazole, triclosan, and trimethoprim) in aerobic and anoxic sludge from a biological nutrient removal (BNR) wastewater treatment system. Liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (LC-QTOF) was used to identify intermediate transformation products. A user-defined compound library was used to target unknowns in samples with a mix of TOrCs without requiring chemical standards and developed using EAWAG-BDD predictive software, which included 37 potential transformation products. Biotransformation batch experiments were conducted using activated sludge from anoxic and aerobic redox regimes of a BNR treatment plant located in Southern Nevada, United States. Four intermediates were observed for benzotriazole in both aerobic and anoxic activated sludge, which consisted of two isomers of hydroxy benzotriazole and two isomers of methoxy benzotriazole. Four intermediates were observed for trimethoprim under aerobic conditions, which formed 2,4-diaminopyrimidin-5-yl)(3,4,5-trimethoxyphenyl)methanol (TMP 306) and 2,6-diamino-5-hydroxy-5-(3,4,5-trimethoxybenzyl)-5,6-dihydropyrimidin-4(1H)-one (TMP 324) and two demethylation isomers of desmethyl trimethoprim. Triclosan had one confirmed transformation product, triclosan-o-sulfate, formed in both conditions. The identification of these transformation products will allow for more thorough risk assessments to be performed for the target TOrCs.

Exploring the operating factors controlling Kouleothrix (type 1851), the dominant filamentous bacterial population, in a full-scale A2O plant

This study reveals that the abundance of the filament Kouleothrix (Eikelboom type 1851) correlated positively with poor settleability of activated sludge biomass in a Japanese full-scale nutrient removal wastewater treatment plant sampled over a one-year period. 16S rRNA amplicon sequence data confirmed that Kouleothrix was the dominant filament in the plant, with a relative abundance of 3.06% positively correlated with sludge volume index (SVI) (R = 0.691). Moreover, Kouleothrix (type 1851) appeared to form interfloc bridges, typical of bulking sludge, regardless of season. Together with earlier studies that indicated the responsibility of Kouleothrix (type 1851) on bulking events, these data suggest that their high relative abundances alone may be responsible for sludge bulking. 16S rRNA qPCR data for this filament showed changes in its relative abundance correlated with changes in several operational parameters, including mixed liquor temperature, sludge retention time, and suspended solids concentration, and it may be that manipulating these may help control Kouleothrix bulking.

Auto-flocculation microalgae species Tribonema sp. and Synechocystis sp. with T-IPL pretreatment to improve swine wastewater nutrient removal

It is recognized coupling microalgae, which is rich in lipids or protein with wastewater treatment offers extra economic benefits that can potentially make microalgal production feasible by reducing production costs and providing environmental benefits. However, the pretreatment of high concentration nutrients such as ammonia nitrogen (NH3-N), total phosphorus (TP) and chemical oxygen demand (COD) in swine wastewater is the premise of application for microalgae in wastewater treatment. This study two auto-flocculation microalgae Tribonema sp. and Synechocystis sp. were selected for evaluation; they were cultivated in diluted swine wastewater together after it was pretreated with titanium dioxide (TiO2) plus intense pulsed light (T-IPL). The results showed that the growth of the two strains in the wastewater pretreated with T-IPL grew better than when grown without the pretreatment. The content of lipid in the two algae, cultured in the pretreated wastewater, was also higher than the lipid content from the un-pretreated wastewater; but protein content was lower. Overall, the removal efficiencies of pollutants NH3-N, TP, and COD by the two microalgae in anaerobic digestion of swine wastewater (ADSW) with T-IPL pretreatment, were higher than the removal efficiencies without pretreatment. This research also indicates that these two auto-flocculation microalgae have the potential to reduce harvesting costs. And, using T-IPL to pretreat wastewater could provide a promising method for the pretreatment of wastewater.

Removal of high concentration of nitrate and phosphate from aqueous mixotrophic solution by Chlorella vulgaris

Microalgae exhibit large potential as an alternative to advanced biological nutrient removal in wastewater or simulated wastewater at laboratory conditions. Therefore, it is necessary to determine the optimum conditions for nutrient removal. This study investigated the total carbohydrate, chlorophyll-a, -b, carotenoid and lipid production and nutrient removal of mixotrophic microalgae ( C. vulgaris ) cultured in different nitrate/phosphate rich modified BG-11 medium (0-200 mg L -1 ) at longer growth periods (10 days). The mean removal efficiency of NO 3 -N (in nitrate source), and PO 4 -P (in phosphate source) (88.29 ±0.12 and 31.06 ±0.22%, respectively) was reached in the mixotrophic culture. Under the optimum conditions (200 µmol photon m⁻ 2 s⁻ 1 16 h photoperiod and 28% inoculum size), 63.61-99.05% of NO 3 - and 13.97-63.77% of PO₄ 3 ⁻were successfully removed. The lipid and carbohydrate productivities were 27.95 and 29.53 g L −1 d −1 , 0.2869 and 0.2435 g L -1 d -1 respectively, which were approximately 9-12 times higher than those in photoautotrophic condition. The BG-11 growth media containing 10 g L −1 glucose and excessive amount of nutrient effect results indicate that the Chl-a, -b and carotenoid contents of C. vulgaris is higher at 100 mg L -1 N and 50 mg L -1 P growth media composition compared to 100% growth media composition. Thereby, the findings of this study provided an insight into the role of algal uptake of nutrients under the nutrient rich mixotrophic medium for the future algae-based treatment application.

Pilot Plant Performance Comparing Carbon-Based and Membrane-Based Potable Reuse Schemes

Two pilot-scale advanced water treatment plants using tertiary-treated biological nutrient removal wastewater effluent were operated simultaneously to demonstrate and compare treatment performances and process operations. Final effluent from both the plants was compared for its suitability to recharge a potable water supply aquifer. The two treatment approaches included a carbon-based treatment process (flocculation/sedimentation, ozone-biofiltration, granular activated carbon (GAC) adsorption, ultraviolet (UV) disinfection; 20,000 L/day) and a membrane-based treatment process (ultrafiltration, reverse osmosis, UV-hydrogen peroxide advanced oxidation; 160,000 L/day). Both processes were found to be reliable in producing water that met all United States Safe Drinking Water Act's primary maximum contaminant levels (MCLs). The carbon-based process often exceeded the secondary MCL for total dissolved solids due to background salinity in the source water. Results showed that both systems performed comparably with respect to removal of pathogens, fecal indicators, and contaminants of emerging concern. Total organic carbon (TOC) was removed to below 0.5 mg/L by the membrane-based process. For the carbon-based process, GAC media exhaustion over the course of the pilot operation resulted in an increase in finished water TOC from <0.5 to ∼4 mg/L. Disinfection byproducts, including trihalomethanes and haloacetic acids were not measured above their respective MCL after 8 h of free chlorine contact in a simulated distribution system test. N-nitrosodimethylamine was removed below 10 ng/L by the GAC with 20 min of empty bed contact time after 20,000 bed volumes.

Estimation of Dominant Bacterial Species in a Bench-Scale Shipboard Sewage Treatment Plant

Recently, an innovative method for wastewater treatment and nutrient removal was developed by combining the sequence batch reactor and membrane bioreactor to overcome pollution caused by shipboard sewage. This system is a modified form of the activated sludge process and involves repeated cycles of mixing and aeration. In the present study, the bacterial diversity and dominant microbial community in this wastewater treatment system were studied using the MACROGEN next generation sequencing technique. A high diversity of bacteria was observed in anaerobic and aerobic bioreactors, with approximately 486 species. Microbial diversity and the presence of beneficial species are crucial for an effective biological shipboard wastewater treatment system. The Arcobacter genus was dominant in the anaerobic tank, which mainly contained Arcobacter lanthieri (8.24%), followed by Acinetobacter jahnsonii (5.81%). However, the dominant bacterial species in the aerobic bioreactor were Terrimonas lutea (7.24%) and Rubrivivax gelatinosus (4.95%).

Influence of light regime on the performance of an immobilised microalgae reactor for wastewater nutrient removal

Microalgae immobilised within a resin shaped into beads have demonstrated the ability to remediate nutrients from wastewater effluents within hydraulic retention times as low as 3h. Methods to further optimise performance consider parameters relating to the bead with the impact of external conditions seldom investigated. Light is an essential parameter for microalgal growth with its effect on suspended cultures well documented. This work explores the influence of light on nutrient remediation by immobilised microalgae in order to recommend an optimal lighting solution for an immobilised microalgae technology based on Scenedesmus obliquus encapsulated within calcium-alginate beads. White light (400–700nm) at a photon flux density (PFD) of 200μmol∙m−2∙s−1 was determined optimal when illuminating a packed bed configuration. When considering phosphate, these conditions supported a remediation rate of 10.7 (± 0.01) mgP∙h−1∙106 beads−1 in comparison to 10.2 (± 0.01) and 10.1 (± 0.01) mgP∙h−1∙106 beads−1 for the blue (465nm) and red (660nm) spectra respectively. Although similar performance was demonstrated, light transmission trials determined white light to penetrate to greater bed depths resulting in a larger photoactive zone. A PFD of 200μmol∙m−2∙s−1 was regarded as optimal when considering performance, attenuation depth and effective use of total supplied light. In addition, photoperiods trials determined lighting periods <12h extended the overall treatment time.

Kinetic of on Nutrient Removal in Low-Strength Domestic Wastewater under Continuous Operation of Pilot Scale of Hybrid Reed Bed System (SF-VF-HF)

Kinetic of on Nutrient Removal in Low-Strength Domestic Wastewater under Continuous Operation of Pilot Scale of Hybrid Reed Bed System (SF-VF-HF)

Selected aspects of water and sewage management in Poland in the context of sustainable urban development

Abstract Effective water and sewage management is one of the most important enablers of sustainable urban development. In Poland, water and sewage management has been undergoing systematic transformation since the 1990s. This process intensified with Poland’s accession to the European Union in 2004. The aim of the work is to analyse and evaluate water and sewage management in cities in Poland in terms of sustainable development. This was made possible by selecting seven variables from which a summative index (SI) was calculated. The analysis revealed a number of positive changes that have occurred in this field. These were mainly: a decrease in water consumption in households and industry, and an increased share of wastewater treated biologically or using enhanced nutrient removal in total wastewater. An increase in SI was found in 98% of the researched cities. The largest improvement in water and sewage management took place in cities of populations below 100,000 and little industry, and in three large cities, namely Warsaw and Szczecin.

Effects of multi-temperature regimes on cultivation of microalgae in municipal wastewater to simultaneously remove nutrients and produce biomass.

Coupling algal cultivation with wastewater treatment due to their potentials to alleviate energy crisis and reduce environmental burden has attracted the increased attention in recent years. However, these microalgal-based processes are challenging since daily and seasonal temperature fluctuation may affect microalgal growth in wastewater, and the effects of the temperature regimes on microalgal biomass production and wastewater nutrient removal remain unclear. In this study, Chlorella vulgaris was continuously cultured for 15 days in municipal wastewater to investigate the effects on the algal biomass and wastewater nutrient removal in three temperature regimes: (1) low temperature (4 °C), (2) high temperature (35 °C), and (3) alternating high-low temperature (35 °C in the day: 4 °C at night). Compared with the other two temperature regimes, the high-low temperature conditions generated the most biomass (1.62 g L-1), the highest biomass production rate (99.21 mg L-1 day-1), and most efficient removal of COD, TN, NH3-N, and TP (83.0%, 96.5%, 97.8%, and 99.2%, respectively). In addition, the polysaccharides, proteins, lipid content, and fatty acid methyl ester composition analysis indicates that in alternating high-low temperature condition, biomass production increased the potential for biofuel production, and there was the highest lipid content (26.4% of total dry biomass). The results showed that the nutrients except COD were all efficiently removed in these temperature conditions, and the alternating high-low temperature condition showed great potential to generate algal biomass and alleviate the wastewater nutrients. This study provides some valuable information for large-scale algal cultivation in wastewater and microalgal-based wastewater treatments.

Development of generalized empirical models for comparing effectiveness of wastewater nutrient removal technologies

The effectiveness of nutrient removal approaches was quantified at four wastewater treatment facilities (WWTFs) using mechanistic models. Generalized empirical models were developed applying statistical methods on the predicted values characterizing nutrient removal as a function of influent wastewater quality. The empirical models provide a framework to estimate nutrient removal effectiveness and inform system-level decisions on technology adoption. When carbon limited, more sophisticated approaches like five-stage Bardenpho and nitrite shunt provide the most notable benefit in removal efficiency (67% ± 3.3% and 89% ± 2.8%, respectively for total nitrogen (TN)), but little benefit is estimated under non-carbon-limited conditions between traditional solutions like anaerobic, anoxic, oxic (A2O), and advanced process configurations like five-stage Bardenpho (82% ± 2.8% and 85% ± 3.3%, respectively for TN). Sidestream physical/chemical processes can provide improvement in removal efficiency particularly at carbon-limited WWTFs, but negligible benefit is estimated with adoption of sidestream biological processes.

Periphytic biomass composition and exploitation from algae turf scrubber system

The algae turf scrubber (ATS) is an excellent system for nutrient removal in wastewater or water bodies. The purpose of this study was to evaluate the production of periphytic biomass in an ATS system installed in a freshwater reservoir and to recognize biomass composition. Mid-infrared spectroscopic analysis was carried out to identify the main composition and variability of biomass using multivariate analysis. The composition was studied for potentiality to use the periphytic biomass for the industry. As a result, the system produced a dry weight of 4.46 g m−2 day−1 of periphytic biomass. It was determined that the biomass contained 43.71% carbon, 6.03% nitrogen, and 2.87% phosphorus. Protein, lipid, and carbohydrate contents were 19.27%, 5.90%, and 65.9%, respectively. Carbohydrate and protein values indicated that the periphytic biomass has a potential for biofuel, fertilizer, and animal feed, and other products; due to the carbohydrate content, application for fermentative products is relevant.

Effects of carboxyl single-walled carbon nanotubes on synthetic wastewater nutrient removal by an algal-bacterial consortium: Regulation and interaction

In this study, the morphology, ultrastructure, nutrient removal, metabolite levels, and interaction of an algal-bacterial consortium exposed to different concentrations of carboxylic single-walled carbon nanotubes (C-SWCNT) were investigated. At a C-SWCNT concentration of 0.05 mg·L−1, the removal rates of TN, NH3-N, PO43−-P, and COD were 94.7%, 94.8%, 86.4% and 84.3%, respectively. When cells were exposed to 50 mg·L−1 C-SWCNT, its intracellular levels in individual algae and the algal-bacterial consortium were 23.6 μg·g−1 and 12.1 μg·g−1, respectively. C-SWCNT (0.05 mg·L−1) promoted the metabolism of fatty acids, amino acids, small molecules, and acid in the algal-bacterial consortium. The main response to the interaction of C-SWCNT and the consortium was the change in extracellular carbohydrate levels. C-SWCNT also increased chlorophyll a and glycine levels. These findings reveal new insights into our understanding of the biological responses and interactions between C-SWCNT and algal-bacterial consortium.