High-strength Organic Wastewater Research Articles

Sustainable power production from petrochemical industrial effluent using dual chambered microbial fuel cell

Dual chambered microbial fuel cell (DMFC) is an advanced and effective treatment technology in wastewater treatment. The current work has made an effort to treat petrochemical industrial wastewater (PWW) as a DMFC substrate for power generation and organic substance removal. Investigating the impact of organic load (OL) on organic reduction and electricity generation is the main objective of this study. At the OL of 1.5 g COD/L, the highest total chemical oxygen demand (TCOD) removal efficiency of 88%, soluble oxygen demand (SCOD) removal efficiency of 80% and total suspended solids (TSS) removal efficiency of 71% were seen, respectively. In the same optimum condition of 1.5 g COD/L, the highest current and power density of about 270 mW/m2 and 376 mA/m2 were also observed. According to the results of this study, using high-strength organic wastewater in DMFC can assist in addressing the issue of the petrochemical industries and minimize the energy demand.

Effects of sudden shock load on simultaneous biohythane production in two-stage anerobic digestion of high-strength organic wastewater

The two-stage anaerobic digestion (AD) for biohythane production is a sustainable solution, but it is sensitive to organic shock load that disrupts reactors and inhibits biohythane production. This study investigated biohythane production, reactor performance, and the possibility of post-failure restoration in a two-stage AD system designed for treating high-strength organic wastewater. Sudden shock load was applied by increasing the OLR threefold higher after reaching steady state phase. During shock load phase, hydrogen content, hydrogen yield and methane production rate (MPR) reached its peak values of 62.61 %, 1.641 mol H2/mol glucose, and 1.003 L CH4/L⋅d respectively before declining significantly. Interestingly, during the restorative phase, hydrogen production sharply declined to nearly zero, while methane production exhibited a resilience and reached its peak methane content of 52.2 %. The study successfully demonstrated the system’s resilience to sudden shock load, ensuring stable methane production, while hydrogen production did not exhibit the same capability.

Advanced Treatment of Coking Wastewater by Polyaluminum Silicate Sulfate for Organic Compounds Removal.

Coking wastewater is a typical high-strength organic wastewater, for which it is difficult to meet discharging standards with a single biological treatment. In this study, effective advanced treatment of coking wastewater was achieved by coagulation with freshly prepared polyaluminum silicate sulfate (PASS). The performance advantage was determined through comparison with commercial coagulants including ferric chloride, polyferric sulfate, aluminum sulfate and polyaluminum chloride. Both single-factor and Taguchi experiments were conducted to determine the optimal conditions for coagulation with CODCr and UV254 as indicators. A dosage of 7 mmol/L PASS, flocculation velocity of 75 r/min, flocculation time of 30 min, pH of 7, and temperature of 20 °C could decrease the CODCr concentration from 196.67 mg/L to 59.94 mg/L. Enhanced coagulation could further help to remove the organic compounds, including pre-oxidation with ozonation, adsorption with activated carbon, assistant coagulation with polyacrylamide and secondary coagulation. UV spectrum scanning and gas chromatography-mass spectrometry revealed that the coagulation process effectively removed the majority of organic compounds, especially the high molecular weight alkanes and heterocyclic compounds. Coagulation with PASS provides an effective alternative for the advanced treatment of coking wastewater.

Potential of direct granulation and organic loading rate tolerance of aerobic granular sludge in ultra-hypersaline environment

Salt-tolerant aerobic granular sludge (SAGS) technology has shown potentials in the treatment of ultra-hypersaline high-strength organic wastewater. However, the long granulation period and salt-tolerance acclimation period are still bottlenecks that hinder SAGS applications. In this study, “one-step” development strategy was used to try to directly cultivate SAGS under 9% salinity, and the fastest cultivation process was obtained under such high salinity compared to the previous papers with the inoculum of municipal activated sludge without bioaugmentation. Briefly, the inoculated municipal activated sludge was almost discharged on Day 1–10, then fungal pellets appeared and it gradually transitioned to mature SAGS (particle size of ∼4156 μm and SVI30 of 57.8 mL/g) from Day 11 to Day 47 without fragmentation. Metagenomic revealed that fungus Fusarium played key roles in the transition process probably because it functioned as structural backbone. RRNPP and AHL-mediated systems might be the main QS regulation systems of bacteria. TOC and NH4+-N removal efficiencies maintained at ∼93.9% (after Day 11) and ∼68.5% (after Day 33), respectively. Subsequently, the influent organic loading rate (OLR) was stepwise increased from 1.8 to 11.7 kg COD/m3·d. It was found that SAGS could maintain intact structure and low SVI30 (< 55 mL/g) under 9% salinity and the OLR of 1.8–9.9 kg COD/m3·d with adjustment of air velocity. TOC and NH4+-N (TN) removal efficiencies could maintain at ∼95.4% (below OLR of 8.1 kg COD/m3·d) and ∼84.1% (below nitrogen loading rate of 0.40 kg N/m3·d) in ultra-hypersaline environment. Halomonas dominated the SAGS under 9% salinity and varied OLR. This study confirmed the feasibility of direct aerobic granulation in ultra-hypersaline environment and verified the upper OLR boundary of SAGS in ultra-hypersaline high-strength organic wastewater treatment.

Environmental and Economic Evaluation of Downflow Hanging Sponge Reactors for Treating High-Strength Organic Wastewater

This study evaluated the performance of a downflow hanging sponge (DHS) in reducing the concentrations of chemical oxygen demand (COD), ammonia (NH3), total suspended solids (TSS), and total dissolved solids (TDS) in high-strength organic wastewater (HSOW). The DHS unit was composed of three segments connected vertically and operated under different organic loading rates (OLRs) between 3.01 and 12.33 kg COD/m3sponge/d at a constant hydraulic retention time (HRT) of 3.6 h. The results demonstrated that the DHS system achieved COD, NH3, TSS, and TDS removal efficiencies of 88.34 ± 6.53%, 64.38 ± 4.37%, 88.13 ± 5.42%, and 20.83 ± 1.78% at an OLR of 3.01 kg COD/m3sponge/d, respectively. These removal efficiencies significantly (p &lt; 0.05) dropped to 76.39 ± 6.58%, 36.59 ± 2.91%, 80.87 ± 5.71%, and 14.20 ± 1.07%, respectively, by increasing the OLR to 12.33 kg COD/m3sponge/d. The variation in COD experimental data was well described by the first-order (R2 = 0.927) and modified Stover–Kincannon models (R2 = 0.999), providing an organics removal constant (K1) = 27.39 1/d, a saturation value constant (KB) = 83.81 g/L/d, and a maximum utilization rate constant (Umax) = 76.92 g/L/d. Adding another DHS reactor in a secondary phase improved the final effluent quality, complying with most environmental regulation criteria except those related to TDS concentrations. Treating HSOW with two sequential DHS reactors was economically feasible, with total energy consumption of 0.14 kWh/m3 and an operating cost of about 7.07 USD/m3. Accordingly, using dual DHS/DHS units to remove organics and nitrogen pollutants from HSOW would be a promising and cost-efficient strategy. However, a tertiary treatment phase could be required to reduce the TDS concentrations.

Environmental biotechnologies can make water pollutants part of the path to mitigating climate change

To slow and ultimately reverse global climate change, society needs to replace fossil sources of energy and chemicals with renewable forms. Environmental biotechnologies, which utilize microbial communities that can provide human society with sustainability services, can play key roles towards this goal in two ways that are the focus of this perspective. First, technologies that employ anaerobic microbial communities can produce renewable, carbon-neutral energy by transforming the energy contained in the organic matter in wastewaters to methane gas, hydrogen gas, or organic chemicals used in the chemical industry. High-strength organic wastewaters are common from many facets of our systems of food supply: e.g., animal farms, food processing, uneaten food, and biosolids from sewage treatment. While anaerobic digestion of sewage biosolids is a long-standing method for making renewable methane, new, more-advanced environmental biotechnologies are making energy-generating anaerobic treatment more reliable and cost-effective for treating the wide range of organics-bearing wastewaters and for producing output with greater economic benefit than methane. Second, photovoltaic, wind, battery, and catalytic technologies require large inputs of critical ninerals and materials: e.g., Rare Earth Elements, Platinum Groups Metals, gold, silver, lithium, copper, and nickel. Environmental biotechnologies can create new, renewable sources of the critical materials by recovering them from wastewaters from mining, ore-processing, refining, and recycling operations. When provided with hydrogen gas as an electron donor, anaerobic bacteria in biofilms carry out reduction reactions that lead to the formation of nanoparticles that are retained in the biofilm and can then be harvested to serve as feedstock for the photovoltaic, wind, battery, and catalytic technologies. This perspective describes both ways in which environmental biotechnologies will help society achieves it sustainability goals.

Aerobic granular sludge treating hypersaline wastewater: Impact of pH on granulation and long-term operation at different organic loading rates

pH is one of the major parameters that influence the granulation and long-term operation of aerobic granular sludge (AGS). In hypersaline wastewater, the impact of pH on granulation and the extent of organic loading rate (OLR) that AGS can withstand under different pH are still not clear. In this study, AGS was cultivated at 3% salinity in three sequencing batch reactors with influent pH values of 5.0, 7.0, and 9.0, respectively, and the OLR was stepwise increased from 2.4 to 16.8 kg COD/m3·d after the granules maturation. The results showed the satisfactory granulation and organic removal under different influent pH conditions, in which the granulation was completed on day 43, 23, and 23, respectively. Neutral influent was the most appropriate for development of salt-tolerant aerobic granular sludge (SAGS), while acidic environment induced the formation of fluffy filamentous granules, and alkaline environment weakened the granule stability. Metagenomic analysis revealed the similar microbial community of neutral and alkaline conditions, with the predominance of genus Paracoccus_f__Rhodobacteraceae. While in acidic environment, fungus Fusarium formed the skeleton of filamentous granules and functioned as the carrier of bacteria including Azoarcus and Pararhodobacter. With the elevation of OLR, SAGSs were found to maintain the compact structure under OLRs of 2.4, 7.2, and 2.4 kg COD/m3·d, and obtain high TOC removal (>95.0%) under OLRs of 7.2, 14.4, and 14.4 kg COD/m3·d, respectively. For hypersaline high-strength organic wastewater, satisfactory TOC removal could also be obtained at broad pH ranges (5.0–9.0), in which neutral environment was the most suitable and acidic environment was the worst. This study contributed to a better understanding of SAGS granulation and treatment of hypersaline high-strength organic wastewater with different pH values.

Simultaneous Removal of Organic Matter and Nutrients from High Strength Organic Wastewater Using Sequencing Batch Reactor (SBR)

Industrial wastewater discharges often contain high levels of organic matter and nutrients, which can lead to eutrophication and constitute a serious hazard to receiving waters and aquatic life. The purpose of this study was to examine the efficacy of using a sequencing batch reactor (SBR) to treat high-strength organic wastewater for the removal of both chemical oxygen demand (COD) and nutrients (nitrogen and phosphorus). At a constant COD concentration of approximately 1000 mg/L, the effects of cycle time (3 and 9 h) and various C:N:P ratios (100:5:2, 100:5:1, 100:10:1, and 100:10:2) were investigated using four identical SBRs (R1, R2, R3, and R4). According to experimental data, a significant high removal, i.e., 90%, 98.5%, and 84.8%, was observed for COD, NH3-N, and PO43−-P, respectively, when C:N:P was 100:5:1, at a cycle time of 3 h. Additionally, when cycle time was increased to 9 h, the highest levels of COD removal (95.7%), NH3-N removal (99.6%), and PO43−-P removal (90.31%) were accomplished. Also, in order to comprehend the primary impacts and interactions among the various process variables, the data was statistically examined using analysis of variance (ANOVA) at a 95% confidence level, which revealed that the interaction of cycle time and C/N ratio, cycle time and C/P ratio is significant for COD and NH3-N removal. However, the same interaction was found to be insignificant for PO43−-P removal. Sludge volume index (SVI30 and SVI10) and sludge settleability were studied, and the best settling was found in R3 with SVI30 of 55 mL/g after 9 h. Further evidence that flocs were present in reactors came from an average ratio of SVI 30/SVI 10 = 0.70 after 9 h and 0.60 after 3 h.

Deeper insight into the effect of salinity on the relationship of enzymatic activity, microbial community and key metabolic pathway during the anaerobic digestion of high strength organic wastewater

The threshold salt concentration to inhibit the anaerobic digestion (AD) has been intensively investigated, but its insight mechanism is not fully revealed. Therefore, this study systematically investigated the effect of salinity on acidogenesis and methanogenesis and its mechanism. Results showed that low salinity level (i.e. 0.6%) had stimulatory effect on volatile fatty acids (VFA) and methane production, while significant inhibition was observed with further increased salinity. Moreover, high salinity limited the butyric acid degradation at acidogenesis process. The decreases of enzymes (AK and PTA) activity and functional genes (ackA, pta and ACOX) expression that related to β-oxidation explained the butyric acid accumulation at high salinity levels. Microbial community analysis revealed high salinity levels significantly inhibited the proliferation of Syntrophomonas sp., which are known to be associated with butyric acid degradation. Similarly, the relative abundance of acetoclastic methanogen (Methanothrix sp.) and methylotrophic methanogen (Methanolinea sp.) significantly decreased at salinity condition.

Erratum for “Integrated Approach to Treatment of High-Strength Organic Wastewater by Using Anaerobic Rotating Biological Contactor” by Milad Ebrahimi, Hamidreza Kazemi, S. A. Mirbagheri, and Thomas D. Rockaway

Erratum for “Integrated Approach to Treatment of High-Strength Organic Wastewater by Using Anaerobic Rotating Biological Contactor” by Milad Ebrahimi, Hamidreza Kazemi, S. A. Mirbagheri, and Thomas D. Rockaway

Membrane fouling of raw coking wastewater in membrane distillation: Identification of fouling potential of hydrophilic and hydrophobic components

The flux decline of raw coking wastewater in membrane distillation (MD) is not serious as expected, yet little is known for such phenomenon. This study provides a systematic analysis of the fouling potential of hydrophilic substances (HIS) and hydrophobic fractions (HOA, HOB, HON) extracted from real coking wastewater. The results showed that HIS had a similar flux decline as compared to raw wastewater, whilst HOA and HOB demonstrated an obviously higher initial flux but a higher fouling rate as well. SEM, AFM and XPS analysis proved that a dense layer was formed for HIS, similar as for raw coking wastewater. However, the pores of HOA, HOB and HON fouled membranes remained open and little inorganic elements were presented. Surface charge results confirmed that hydrophobic fractions were negatively charged but the hydrophilic fraction was nearly neutral. Considering the negatively charged membrane surface, HIS was more readily to form a dense layer. With such a hydrophilic protective layer, the heat transfer resistance increased suddenly, leading to a lower initial flux but a lower fouling rate at the same time. This study provides a theoretical fundamental for understanding membrane fouling of high-strength organic wastewater, which is helpful for further development of MD technology.

Simultaneous production of hydrogen-methane and spatial community succession in an anaerobic baffled reactor treating corn starch processing wastewater

Corn starch processing wastewater (CSPW) is a high-strength organic wastewater and biological treatment is considered as the dominant process. The present work investigated the effects of pH on the bioenergy production and spatial succession of microbial community in an anaerobic baffled reactor (ABR) treating CSPW. The results showed that above 90.5% of COD removal and above 16.6 L d−1 of methane were achieved at the influent pHs of 8.0 and 7.0 under organic loading rate of 4.0 kg COD·m−3·L−1 condition. Further decreasing the influent pH to 6.0 resulted in the COD removal decreased to 89.7%. Besides, 9.2 L d−1 of hydrogen and 13.0 L d−1 of methane were obtained. There was significant difference in the volatile fatty acids profiles during the variation of pH. Illumina Miseq sequencing showed that Clostridium, Ethanoligenens, Megasphaera, Prevotella and Trichococcus with relative abundance of 2.1%∼28.1% were the dominant hydrogen-producing bacteria in C1. Methanogens (Methanothrix and Methanobacterium) dominated in the last three compartments. Function predicted analysis revealed that the abundance of metabolic-related gene families containing carbohydrate, amino acids and energy in the last three compartments were higher than that in C1. A deduced biodegradation model of CSPW in ABR revealed that the anaerobic sludge in C1 mainly produced hydrogen. Microbial population in C3 was responsible for COD removal and methane production. The redundancy analysis revealed that hydrogen production was highly correlated with some hydrogen-producing bacteria in C1, whereas methane production was positively correlated with microbial group in C2∼ C4.

Deeper Insight into the Effect of Salinity on the Relationship of Enzymatic Activity, Microbial Community and Key Metabolic Pathway During the Anaerobic Digestion of High Strength Organic Wastewater

Deeper Insight into the Effect of Salinity on the Relationship of Enzymatic Activity, Microbial Community and Key Metabolic Pathway During the Anaerobic Digestion of High Strength Organic Wastewater

Processing of electroplating industry wastewater through dual chambered microbial fuel cells (MFC) for simultaneous treatment of wastewater and green fuel production

Microbial fuel cells (MFC) provide a breakthrough development for wastewater treatment combined with electricity production. Though, MFC applications are restricted in laboratory scale level. Present study an effort has been made to employ the electroplating industrial wastewater as feedstock in dual chambered anaerobic microbial fuel cell for organic content removal as well as energy production. The ultimate goal of this research is to analyze the effect of organic load (OL) on removal of organic matter and power production. The maximum removal efficiency of total, soluble oxygen demands (TCOD, SCOD) and total suspended solids (TSS) of about 87%, 79% and 72% respectively was obtained at the OL of 1.5 gCOD/L. The maximum power and current density of about 260 mW/m2 (6.2 W/m3) and 364 mA/m2 was also recorded at a same OL of 1.5 gCOD/L. From the above findings proposed that utilization of high strength organic wastewater in MFC could pave the way to handle the problem of electroplating industries as well as minimize a small portion of energy demand.

Integrated valorization system for simultaneous high strength organic wastewater treatment and astaxanthin production from Haematococcus pluvialis

High-strength organic wastewater, e.g., potato juice wastewater, exerts high stress on the environment. This study proposes an integrated system for simultaneous high-strength organic wastewater treatment and nutrients upcycling for astaxanthin production by the combination of anaerobic processes and microalgae (Haematococcus pluvialis) cultivation. The potato juice wastewater was pretreated by either acidification or methanation. The effluents of both pretreatments achieved higher biomass yields of H. pluvialis compared to cultivation in standard culture media (control). The high acetate and potassium concentrations of the acidification effluents resulted in significantly higher astaxanthin production (24.5–27.9 mg g−1, 3 days) compared to the control (14.7 mg g−1, 12 days) in a shorter period. The integrated system contributed to a final removal efficiency of 51.3–75.8%, 86.5–98.3%, and 69.4–83.4% for COD, phosphorus, and ammonia, respectively. This study presents a promising two-stage process for simultaneous efficient methane and astaxanthin production, as well as remediation of high-strength organic wastewater.

고농도 유기성 산업폐수 처리를 위한 복극층 전극반응기의 적정처리조건 탐색

고농도 유기성 산업폐수 처리를 위한 복극층 전극반응기의 적정처리조건 탐색

Development of aerobic methane oxidation, denitrification coupled to methanogenesis (AMODM) in a microaerophilic expanded granular sludge blanket biofilm reactor

The issue of enhancing nitrogen removal and managing dissolved methane emission in anaerobic treatment systems is a major bottleneck in its wider application to treat high-strength organic wastewater with nitrate. Herein, a novel aerobic methane oxidation, denitrification coupled to methanogenesis (AMODM) process was developed in a glucose-fed microaerobic expanded granular sludge blanket biofilm reactor (EGSBBR) through in-situ utilization of produced methane for nitrogen removal. The 162-day operation demonstrated that long-term treatment performance under the decreased COD/NO3−-N (C/N) ratio from 66.7 to 10 and the optimal C/N ratio for completing AMODM was found to be 16.7. Microbial community analysis further evidenced that Methanothrix as key methanogen predominated in the sludge bed, while Methlogaea as aerobic methane oxidizer was mainly detected in the packing bed of the hybrid system. Meanwhile, some facultative heterotrophic and dissimilated nitrate-reduction (DNRA) genera also co-existed. The profiling of key functional genes further proved concurrent occurrence of methanogenesis, aerobic methane oxidation and denitrification. Furthermore, possible microbial mechanism on AMODM process was elucidated from the prospective of targeted species interaction within the reactor. This research provides a robust and environment-friendly alternative process treating nitrate-containing organic wastewater towards efficient nitrogen removal, low resource consumption, bioenergy recovery and greenhouse gas reduction.

Evaluation of anaerobic membrane bioreactor (AnMBR) treating confectionery wastewater at long-term operation under different organic loading rates: Performance and membrane fouling

An anaerobic membrane bioreactor (AnMBR) system treating confectionery wastewater was operated for 247 days at various organic loading rates (OLRs) of 1.1, 2.2, 4.4, 6.6 and 7.9 kg COD m−3 d−1 to determine sustainable OLR. In this study, up to 99% COD removal efficiency was obtained at all OLRs, and the maximum methane production of 0.26 m3 kg−1 CODremoved was achieved at OLR 7.9 kg COD m−3 d−1. Next Generation Sequencing (NGS) analysis showed that the dominance of hydrogenotrophic methanogens shifted to acetoclastic methanogens after OLR value of 4.4 kg COD m−3 d−1, which caused a decrease in the biogas methane composition. The increase in OLR, negatively affected the membrane filtration performance. After OLR value of 4.4 kg COD m−3 d−1, TMP, filtration resistance and EPS/SMP production increased sharply. These results indicated that the AnMBR system could be efficiently operated efficiently at OLR 4.4 kg COD m−3 d−1. Membrane fouling mechanism was evaluated using Fourier-transform infrared spectroscopy (FTIR), atomic force microscopy (AFM), scanning electron microscopy coupled with energy dispersive X-ray (SEM-EDX), and contact angle measurements after 247 days of operation. The results demonstrated that the membrane fouling mechanism can be attributed to cake layer formation which mainly consisted of protein and carbohydrate. In this study, the efficient treatment of confectionery wastewater showed that the AnMBR system could be applied to high-strength organic wastewater such as industries of beverage, beer, dairy, and sugar product. Filtration performance should be enhanced with further investigations.

Long-Term Effects of Polyvinyl Chloride Microplastics on Anaerobic Granular Sludge for Recovering Methane from Wastewater.

Polyvinyl chloride microplastics (PVC-MPs) are emerging contaminants affecting biological wastewater treatment processes. However, most of the previous studies mainly focused on their short-term impacts on floc sludge, with little work being conducted to explore their potential effects on more complex anaerobic granular sludge (AGS), which has been widely used for high-strength organic wastewater treatment. In this paper, the long-term effects of PVC-MPs on AGS were investigated via continuous feeding tests that are representative of real wastewater treatment processes. The results of a continuous 264 days test showed that the prolonged exposure of PVC-MPs at 15-150 MPs·L-1 significantly (p = 7.86 × 10-37, 3.44 × 10-43, and 5.29 × 10-46) inhibited the COD removal efficiency of AGS by 13.2%-35.5%, accompanied by a 11.0%-32.3% decreased production of methane and 40.3%-272.7% increased accumulation of short-chain fatty acids (SCFAs). In addition, the PVC-MPs exposure suppressed the secretion of extracellular polymeric substances (EPS), causing AGS and the inside microorganisms to lose the protection of EPS, thereby resulting in granule breakage and decreased cells viability. Aligning with the deteriorated performance, the long-term exposure of PVC-MPs reduced the total microbial populations and the relative abundances of key methanogens and acidogens. A toxicity mechanism assessment revealed that the negative impacts induced by PVC-MPs are mainly attributed to the toxic leachate and excess oxidative stress.

Techno-Economic Analysis of Electrocoagulation on Water Reclamation and Bacterial/Viral Indicator Reductions of a High-Strength Organic Wastewater—Anaerobic Digestion Effluent

This study investigated the use of iron and aluminum and their combinations as electrodes to determine the technically sound and economically feasible electrochemical approach for the treatment of anaerobic digestion effluent. The results indicated that the use of iron as anode and cathode is the most suitable solution among different electrode combinations. The reduction of turbidity, total chemical oxygen demand, total phosphorus, total coliforms, Escherichia coli, Enterococci, and phages in the reclaimed water were 99%, 91%, 100%, 1.5 log, 1.7 log, 1.0 log, and 2.0 log, respectively. The economic assessment further concluded that the average treatment cost is $3 per 1000 L for a small-scale operation handling 3000 L wastewater/day. This study demonstrated that the electrocoagulation (EC) is a promising technique for the recovery and reclamation of water from anaerobic digestion effluent. Even though its energy consumption is higher and the nitrogen removal is insufficient compared to some conventional wastewater treatment technologies, there are several advantages of the EC treatment, such as short retention time, small footprint, no mixing, and gradual addition of coagulants. These features make EC technology applicable to be used alone or combined with other technologies for a wide range of wastewater treatment applications.