Removal Rate Of NH3-N Research Articles

Treatment of high-concentration semi-coke wastewater by phenolic condensation and persulfate oxidation

In this study, the combined process of phenolic condensation-persulfate(PS) advanced oxidation was adopted to treat semi-coking wastewater. Using the phenolic condensation method as a pretreatment unit to remove phenolic substances for the preparation of phenol-formaldehyde resins, and using an aerated/PS/pyrite oxidation system as a deep treatment unit to remove chemical oxygen demand (COD) and ammonia nitrogen (NH3-N) from the wastewater. Analysis and characterization of phenol-formaldehyde resin, organic compounds in wastewater, and pyrite using FT-IR, TG-DTG, GC-MS, and XPS techniques. The results showed that under the conditions of adding 1.8vt % formaldehyde, pH 10.5, reaction temperature 95 ℃ and reaction time 3 h, the removal rates of volatile phenol, COD and NH3-N in semi-coke wastewater were 97.54 %, 41.14 % and 56.50 %, and the yield of phenolic resin was 6.62 g/L. Subsequently, treated with an aerated/PS/pyrite system, the PS concentration 0.4 mol/L, the pyrite dosage 15 g/L, the pH 3, the temperature 65 ℃, and the aeration 3 h, the removal rates of COD and NH3-N are 99.20 % and 86.80 %. In the phenolic condensation process, phenolic substances in semi-coke wastewater generate phenoxy anions under the influence of OH-, which undergo addition reactions with formaldehyde to produce hydroxymethyl phenol. Hydroxymethyl phenol further undergoes condensation reactions with other phenolic substances and itself to form phenolic resin, while amide compounds are generated through reactions between ammonia nitrogen and carboxylic acid substances. In the aeration/PS/pyrite system, Fe2+ released from pyrite oxidation activates PS to produce SO4•− and O2•−. The contribution of free radical oxidation and decomposition of pollutants such as phenols, amides, and NH3-N in wastewater is 84.60 %. Specifically, SO4•− oxidation contributes 61.54 %, while O2•− accounts for 22.21 %. Amide compounds and phenolic substances in the wastewater are oxidized, leading to ring opening and chain scission, resulting in the formation of alkane compounds.

Experimental study on surface optimization of dosage in magnetic coagulation process for enhancing primary treatment of urban sewage

This work aims to investigate the minimum dosage required to achieve optimal removal of carbon, nitrogen, and phosphorus in the Chemical Enhanced Primary Treatment (CEPT) process using magnetic coagulation technology. A response surface methodology was adopted to generate multiple regression models to optimize the dosages of three types of coagulation, i.e., polyaluminum chloride (PAC), polyacrylamide (PAM), and magnetic medium Fe3O4 particles (MP), based on the removal rates of chemical oxygen demand (COD), ammonia nitrogen (NH3-N), and total phosphorus (TP). The results showed that the regression models could predict results well with actual engineering results. Compared to the traditional coagulation process, the synergistic enhancement of PAC+PAM+MP in the CEPT process significantly improved the treatment effects. Based on the COD removal rates, PAC performed better than MP, followed by PAM; likewise, for the NH3-N and TP removal rates, PAC outperformed PAM, followed by MP. The optimized PAC, PAM, and MP dosages were 135.87, 1.51, and 108.36 mg/L, respectively, reaching 92.27 % COD, 71.98 % NH3-N, and 91.33 % TP removal rates with less than 5 % errors compared to the experimental verification results. These optimization models offer a practical and cost-saving reference for enhancing the primary treatment effect on carbon, nitrogen, and phosphorus removal using PAC+PAM+MP.

Supercritical hydrothermal combustion and enhanced degradation characteristics of phenol

Supercritical hydrothermal combustion is a green combustion technology that produces flames in supercritical water (SCW), which can realize efficient disposal of aqueous wastes. In this study, the typical pollutant phenol is investigated through tubular reactor experiments and mechanism analysis to explore its hydrothermal combustion properties and enhanced degradation effects on refractory species. The results show that 3.06 and 3.41 wt% phenol can be self-ignited in the tubular reactor with a critical preheating temperature of 460 °C. Methanol could improve the ignition and burnout characteristics of phenol. As the COD ratio of methanol was greater than 0.35, the ignition temperature of phenol was reduced to 420 °C, with TOC removal rate achieving 99.9%. At 460 °C, phenol positively influenced the heat release during combustion of phenol/methanol. In oxidation of phenol/ammonia, 1.61 wt% phenol resulted in the reaction temperature rising by around 62.0 °C, allowing a NH4-N removal rate of 92.8% through its synergistic kinetic and thermal effects. Whereas, the nitrogen-containing intermediates from ammonia inhibited phenol oxidation. Finally, a mechanism-based kinetics model for oxidation of phenol in SCW was developed by means of real gas properties and sensitive reaction step modifications, which was viable for simulating the ring-opening path of phenol.

Study on the operation effect of old and new process replacement based on denitrification deep bed filters

In order to study the effect of replacing old and new processes in denitrifying deep-bed filter, the water quality data before and after equipment upgrading at the same period were collected for comparative analysis. The results show that the new process has a desirable removal rates for COD (93.67%), BOD (96.82%), NH3-N (98.04%) and SS (97.47%) throughout the year, respectively, with the effective and feasible denitrification process. The average TN concentration in effluent was 6.1mg/L after process upgrading, which decreased by 41.69% compared with the same period before process upgrading. The average removal rate was 72.5%, which was much higher than that before replacement (58.8%). In general, the denitrification deep bed filter had a great nitrogen removal efficiency.

Comparative analysis of operating efficiency for two sewage treatment processes

To decrease pollutant effluent levels in sewage plants, in order to improve the pollutant control capacity, the removal efficiencies for COD, TP, TN, and NH3-N in two sewage plants located in Guangzhou were compared and analyzed. The correlation among influent carbon and nitrogen ratios, water loading rate, and total nitrogen removal rate were examined to enhance the nitrogen removal. The CASS process in Plant I had slightly higher TN (81.85%) and TP (98.38%) removal rates than those in Plant II (80%). Plants I and II achieved COD removal rates of 95.51% and 96.44%, respectively, and NH3-N removal rates of 99.08% and 99.34%, respectively. Correlation analysis showed that only the influent loading rate of Plant I had a moderate correlation with the total nitrogen removal rate, while the other factors only had a weak correlation. Therefore, the total nitrogen removal rate is influenced by multiple factors.

Optimized electrochemical treatment of semi-coking wastewater for enhanced degradation of biological toxicity using a Ru-Ir-Ti anode and Co-Ti cathode

The Co-Ti cathode was prepared to reduce the biological toxicity of semi-coke wastewater by electrochemical system with commercial ruthenium-iridium titanium (Ru-Ir-Ti) anode. Meanwhile, the removal rate of chemical oxygen demand (COD), volatile phenol (VP) and ammonia nitrogen (NH3-N) in wastewater were also evaluated. Hence, the influence of processing time (A), dilution multiple (B), initial pH (C), electrolyte concentration (D) and current density (D) were systematic explored. After treatment, with the optimized experiment condition of processing time (150 min), dilution multiple (300 times), initial pH (3.2), electrolyte concentration (0.15 mol/L), current density (16 mV/cm2), the B/C value of wastewater was greatly improved from 0.12 to 0.31, the removal rate of COD, NH3-N and VP was 96.82 %, 92.34 % and 97.07 %, respectively. The sequence of significance was B>D>E*E>B*D>A*D>D*D. This most effective degradation was owing to the simultaneously oxidization of both cathode and anode, turning the highly biological toxic wastewater to the biodegradable one. The direct oxidation reaction happened on anode, furthermore, the indirect oxidation reaction would be accelerated near the cathode because of active free radicals generation such as ·OH and O2•– when the cobalt’s valence changed from +2 to +3. It deserve to be mentioned in this research is that the direct and indirect oxidation simultaneously contributed to the degradation of biological toxicity, which is great beneficial for the further bio-chemical processing.

Straw Biochar and Graphite Oxide Enhanced External Pressure Ultrafiltration for Leaded Wastewater Treatment.

In order to solve the problem of the low treatment efficiency of wastewater containing heavy metals in mining areas, straw biochar and graphene oxide enhanced external pressure ultrafiltration (SGU) was used to treat wastewater containing high concentrations of Pb2+. The operation parameters such as pH and temperature were optimized, and the removal efficiency of CODCr, NH3-N, turbidity and Pb2+ via SGU, straw biochar ultrafiltration (SU), ultrafiltration (UF), and conventional treatment (CT) were systematically investigated. The results showed that the pH and temperature of polluted water were 4.8-5.2 and 21-30 °C, respectively, the average removal rates of CODCr, NH3-N, turbidity and Pb2+ by SGU reached 91%, 97%, 98% and 95%, respectively, and the removal effect was better than that of other processes. In addition, under the backwash conditions of clean water, weak acid, and weak alkali, the membrane flux recovered 65%, 88%, and 89% of the new membrane, respectively. This study provides scientific and theoretical support for the advanced treatment of polluted water in mining areas.

Treatment of mature landfill leachate using chemical and electrical Fenton with novel Fe-loaded GAC heterogeneous catalysts

In this study, heterogeneous Fenton catalysts were prepared by loading iron oxides on granular activated carbon (GAC), with which as heterogeneous Fenton catalysts, mature landfill leachate (MLL) was treated by chemical and electrical Fenton method. For chemical Fenton treatment of MIL, the optimum conditions were optimised by orthogonal experiments and the removal of COD, NH3-N and colour reached 93.7 %, 65.5 % and 84 % respectively for static experiments, whereas the heterogeneous Fenton fluidized bed reactor removed >90 % of COD in all the 12 h of continuous operation. For electrical Fenton treatment of MIL, the removal rates of COD, colour, NH3-N, and TN were 97.4 %, 99 %, 100 %, and 94.2 %, respectively under the optimum treatment conditions of pH = 5, the GAC/α-FeOOH catalyst dosage of 13.3 g L−1, and the applied voltage of 8 V with the energy consumption of only 0.23 kWh (g COD)−1. Upon characterization, humic acid, fulvic acid and xanthohumic acid in the MLL were completely degraded and the complex macromolecules such as polycyclic aromatic hydrocarbons and heterocyclic rings were reduced and converted to simple small molecules such as alkanes. The quenching experiments verified that the ·OH produced in the heterogeneous electrical Fenton system plays an important role in the degradation of MLL, while the removal of NH3-N also relies on indirect oxidation with the active chlorine produced by the electrochemical system. GAC-based heterogeneous Fenton catalysts with high catalytic capacity and easy recycling have good application prospects in treating MLL.

Comparative study of Fe2+/H2O2 and Fe2+/persulfate systems on the pre-treatment process of real pharmaceutical wastewater.

Advanced oxidation technologies based on hydroxyl radical (•OH) and sulfate radical (SO4-•) are two common types of advanced oxidation technologies, but there are not many reports on the application of advanced oxidation methods in actual wastewater pretreatment. This article compares the pre-treatment performance of Fe2+/H2O2 and Fe2+/Persulfate systems in actual pharmaceutical wastewater, and combines EEM, GC-MS, and toxicity testing results to explore the differences in TOC, COD, and NH3-N removal rates, optimal catalyst dosage, applicable pH range, toxicity of effluent after reaction, and pollutant structure between the two systems. The results indicate that the Fe2+/H2O2 system has a higher pollutant removal rate (TOC: 71.9%, COD: 66.9%, NH3-N: 34.1%), but also requires a higher catalyst (Fe2+) concentration (6.0 g/L), and its effluent exhibits characteristic peaks of aromatic proteins. The Fe2+/Persulfate system has a wider pH range (pH ≈ 3-7) and is more advantageous in treating wastewater containing more cyclic organic compounds, but the effluent contains some sulfur-containing compounds. In addition, toxicity tests have shown that the toxicity reduction effect of the Fe2+/Persulfate system is stronger than that of the Fe2+/H2O2 system.

Effects of Cu (II) on the Growth of Chlorella vulgaris and Its Removal Efficiency of Pollutants in Synthetic Piggery Digestate.

C. vulgaris has a positive effect on the removal of nutrients from pig farm biogas slurry. However, swine wastewater often contains heavy metal ions, such as Cu (II), which may have impacts on the nutrient removal performance of C. vulgaris. Additionally, the heavy metal ions in wastewater can be adsorbed by microalgae. In this study, the stress effect of Cu (II) on the growth of Chlorella vulgaris, the Cu (II) removal by microalgae, and the effect of different concentrations of Cu (II) on the nutrient removal efficiency of C. vulgaris in biogas slurries were explored. The results showed that the microalgae biomass of microalgae on the sixth day of the experiment was the highest in the treatment with a Cu (II) concentration of 0.5 mg/L, which was 30.1% higher than that of the 2.5 mg/L group. C. vulgaris had higher removal efficiencies of Cu (II) at a Cu (II) concentration of 0.1~1.5 mg/L. The-OH, C=O, -COOH, and C-O groups on the surface of the algal cells play a significant role in the removal of Cu (II). The removal rates of COD, NH3-N, TN, and TP by C. vulgaris at a Cu (II) concentration of 0.5 mg/L were the highest, which were 89.0%, 53.7%, 69.6%, and 47.3%, respectively.

Integration of hydrothermal liquefaction of Cyanophyta and supercritical water oxidation of its aqueous phase products: Biocrude production and nutrient removal

Cyanophyta has the potential to produce biocrude via hydrothermal liquefaction (HTL). However, aqueous phase products (APs), as by-products of HTL, pose a risk of eutrophication for the high levels of carbon, nitrogen, and phosphorus. Supercritical water oxidation (SCWO) can efficiently convert organics into small molecules, offering a technique for the harmless treatment of APs. Effects of holding time, pressure, and moisture content on the biocrude yields from isothermal HTL (300 °C) and fast HTL (salt bath temperature of 500 °C) were comprehensively investigated. Biocrude properties were characterized by elemental analysis, FT-IR and GC–MS. Subsequently, the APs obtained under the conditions producing the highest biocrude yield were subjected to SCWO at 550 °C with different oxidation coefficients (n) from 0 to 2. Removal rates of chemical oxygen demand (COD), ammonia nitrogen (NH3−N), and total phosphorus (TP) were further explored. The results show that the highest biocrude yields from isothermal HTL and fast HTL were 24.2 wt% (300 °C, 1800 s, 25 MPa, and 80 wt% moisture content) and 21.9 wt% (500 °C, 40 s, 25 MPa, and 80 wt% moisture content), respectively. The biocrude primarily consisted of N-containing heterocyclic compounds, amides, and acids. SCWO effectively degraded the COD and TP in APs, while the NH3-N required further degradation. At n = 2, the highest removal rates of COD, NH3-N and TP were 98.5 %, 22.6 % and 89.1 %, respectively.

Degradation kinetics of organic matter in domestic sewage by sequencing batch reactor

The sequencing batch reactor (SBR) has become a popular sewage treatment process in various industries due to its strong impact load resistance and numerous other advantages. This study examines the variations of chemical oxygen demand chromium (CODcr), ammoniacal nitrogen (NH3-N), total bound nitrogen (TN) and total phosphorus (TP) with aeration time to investigate the degradation patterns of different pollutants during the SBR’s reaction stage. Additionally, an organic matter degradation kinetic model was developed. The experimental results showed that the CODcr and NH3-N in the reactor met the national discharge standards after two hours of influent. Furthermore, the removal rates of CODcr and NH3-N exceeded 85% and 99%, respectively, at the end of the final aeration. At the same time, the TN and TP removal rates remained stable at approximately 45% and 68%. The analysis of the kinetic model showed that the degradation process of organic matter followed a first-order kinetic equation: S=S0e−0.00012Xt. The regression model's fitting value exhibited a high degree of conformity with CODcr removal’s experimental results, with the average relative error of 5.52% falling within an acceptable range. Furthermore, the correlation coefficient (0.9966) indicated high accuracy and effectively represented the changes in organic matter throughout the SBR reaction stage. Consequently, this model can serve as a theoretical foundation for determining CODcr’s maximum treatment capacity in experimental wastewater.

Treatment of aquaculture wastewater by C-MFCs

Chlorella microbial fuel cells (C-MFCs) may be an alternative technology for wastewater treatment. Using microalgae and activated sludge as raw materials, the anode of the MFC was connected in series with a chlorella reactor to establish C-MFCs, so that the simulated aquaculture wastewater was first anaerobically treated in the anode chamber and then aerobically treated in the chlorella reactor. The study found that at a 3:1 N:P ratio and 1000 Ω external resistance, NH3N, COD, and TP removal rates were 69.93 ± 1.84 %, 80.30 ± 3.4 %, and 54.44 ± 4.5 %, respectively, with a maximum chlorophyll content of 0.1049 mg∙m−3. The maximum voltage and maximum power density of 32.94423 mV and 102.37 mW∙m−2. The microbial community structure of the anode chamber was analyzed and the results were as follows: At N:P = 3:1, the dominant bacteria at the genus level in the anode chamber were Klebsiella (47.23 %) and Glucuronobacterium (28.87 %). It can be concluded that N:P affects the power generation capacity of C-MFCs and the removal of NH3N, COD, and TP. The power generation capacity and removal of NH3N, COD, and TP by C-MFCs were best when N:P = 3:1. The regulation of nitrogen and phosphorus in aquaculture wastewater can effectively enhance the performance of C-MFCs.

Electrocatalytic removal of phenol from coking wastewater using coal based electrode materials

An efficient electrochemical system for phenol degradation in coking wastewater was established. Wherein the economic homemade coal electrode materials (CEMs) and titanium electrode were used as the work electrodes. The removal rate of phenol (R) was 70.18% before optimized and 99.91% after optimized by response surface method (RSM) in phenol synthetic wastewater, and the removal rate of TOC was 72.81%. The operating conditions are: current density of 10 mA/cm2, initial phenol concentration of 100 mg/L, pH of 2, processing time of 270 min and electrolyte concentration (NaCl) of 0.7 mol/L. The R was 95.23% in actual coking water experiment with this process conditions, meanwhile the average removal rate of COD and NH3-N was 93.56% and 85.0%. The free radical quenching experiments result by different dose of tert-butanol (TBA) proved the dominant active material of·OH in oxidation process, the R was decreased from 99.91% to 73.24% (TBA: 0.7 mol/L) and 37.53% (TBA: 2.0 mol/L). The intermediates products most likely existed as hydroquinone, benzoquinone and catechol. synergistic effect on adsorption and oxidation of the electrode was certified. The whole process included three consecutive stages as adsorption, oxidation, desorption/oxidation. CEMs provided the active adsorption site and micro-electric field to improve the efficiency of oxidative degradation.

An integrated process of Fe/C micro-electrolysis-anaerobic hydrolyze-microalgae for treatment of high concentration pharmaceutical wastewater

As a high concentration wastewater of high organic matter content, many toxic substances, large amounts of organic solvents and poor biochemistry, pharmaceutical wastewater is challenging to handle with a single water treatment technology. In this study, a combined process of Fe/C micro-electrolysis (Fe/C-ME)-anaerobic hydrolyze-microalgae was developed to treat high-concentration pharmaceutical wastewater (i.e. 100,000 mg/L chemical oxygen demand (COD), 2800 mg/L ammonia nitrogen (NH3-N) and 130 mg/L total phosphorus (TP)). Firstly, in the Fe/C-ME process, under optimal experimental conditions, the removal rates of COD, NH3-N and TP were 55 %, 36 % and 63 %, and it was worth mentioning that the removal of ammonia nitrogen and total phosphorus may be attributed to the complexation and flocculation of hydrated iron ions. Secondly, the outer circulation anaerobic reactor (OCAR) performed biochemical treatment on pretreated pharmaceutical wastewater, 85 % of COD was removed, and it was found that through anaerobic digestion, and further hydrolyzed and acidified macromolecular pollutants into small molecules to reduce the impact load, which was conducive to the subsequent digestion and absorption of microalgae and improved the treatment efficiency of the aerobic section. The microalgae cultivated by heterotrophy using anaerobic effluent, directly used NH3-N and TP in wastewater to synthesize substances needed for self-growth and reproduction, and removed 88 %, 91 % and 83 % of COD, NH3-N and TP, respectively. The final results indicated that the removal rates of COD, NH3-N and TP in the integrated process of Fe/C-ME-anaerobic hydrolysis-microalgae were 99.8 %, 98.6 % and 98.5 %, respectively, demonstrating that the coupling process is an effective method for treating high-concentration pharmaceutical wastewater.

Simultaneous degradation efficiency of C-MFCs for three pollutants in aquaculture wastewater

<p>Chlorella microbial fuel cells may be an alternative technology for wastewater treatment. Using microalgae and activated sludge as raw materials, a C-MFCs was established, and the effects of different nitrogen and phosphorus ratios in the influent on the electrochemical performance of C-MFCs and the removal effect of NH3-N, COD and TP were investigated. The results show that when N:P=3:1 and the external resistance is 1000 Ω, the removal rates of NH3-N, COD and TP are 72.48±1.94%, 81.26±4.4% and 65.62%±2.14%, respectively, and the highest chlorophyll a content is 108.82 mg/L. The maximum voltage and maximum power 92.94 mV and 234.01 mW/m2. The microbial community structure in the anode chamber was analyzed and the results are as follows: At N:P=3:1, the dominant bacteria at the genus level in the anode chamber were Klebsiella (32.12%) and Prevotella (14.45%). The number of OTUs in the anode chamber changes under different N:P conditions. It can be concluded that N:P affects the power generation capacity of C-MFCs and the removal of NH3-N, COD and TP. Overall,when N:P=3:1, the C-MFCs had the best power production capacity and the removal of NH3-N, COD and TP. Regulation of N:P in aquaculture wastewater is an effective way to improve performance of C-MFCs.</p>

Use of dewatered sludge and fly ash to prepare new fillers: Application and evaluation in wastewater treatment

Fillers are core components of biofilm wastewater treatment systems and directly affect the pollutant removal efficiency. New fillers were prepared using a non-sintered process with dewatered sludge as the raw material. The structure of the new filler and the microbial community were investigated and the results showed that the new filler had a complex composition and nature, a large specific surface area and many attached microorganisms; the new filler was applied to the biological aerated filter (BAF) system and the amount of biofilm on the surface of the new filler was 102 mg/g during start-up. At an hydraulic retention time (HRT) of 6 h and a gas to water ratio of 7:1, the removal rates of COD, NH3-N and TN of the new BAF (biological aerated filter) system reached 74%, 73% and 32%, respectively. At different filler heights, the biofilm amount, biological activity, and pollutant removal effectiveness of the new filler were higher than those of the conventional filler. The microbial diversity and microorganism selectivity of the new filler BAF system were better and more abundant than those of the conventional filler. The study results could provide some scientific basis and technical support for applying the new filler in biofilm wastewater treatment systems.

Performance, microbial community, and metabolism pathway in adsorption-biological coupling reactor treating sulfonamide antibiotics wastewater: Effect of influent frequency and aeration rate

Coke was used as adsorbent to explore the performance of an adsorption-biological coupling reactor when treating sulfonamide antibiotics (SAs) wastewater under different influent frequencies and aeration rates. Meanwhile, the effects of SAs on the microbial community dynamics and metabolomics of the coupling reactor were also investigated. Results showed that the treatment efficiency on SAs wastewater was the best when the influent frequency was once every two days (0.80 L each time) and the aeration rate was 10.00 mL/min. The average removal rate of COD, TP and NH3-N was 95.68 %, 66.09 %, 97.84 %, respectively. Meanwhile, the average removal rates of sulfadiazine (SD) and sulfamethoxazole (SMX) were 88.29 % and 96.76 %. Plasticicumulans, Nakamurella, and Pseudomonas were the main functional bacteria. The nitrate reductase gene (narGH) and phosphate-specific transport system subunit (pstSC) were the genes with the highest average abundance of nitrogen and phosphorus metabolism. Further, 4-hydroxy-2-hydroxylaminopyrimidine, N-phenylacetamide, 4-aminophenol, and hydroquinone were detected as SD and SMX intermediate metabolites. Therefore, the use of adsorption-biological coupling technology to wastewater containing SAs has a certain application prospects.

Treatment of compressed leachate from refuse transfer stations by freeze-melt method

A small amount of leachate with complex composition will be produced during the compressing of municipal solid waste in refuse transfer stations. In this study, the freeze-melt method, a green and efficient wastewater treatment technology, was used to treat the compressed leachate. The effects of freezing temperature, freezing duration, and ice melting method on the removal rates of contaminants were investigated. The results showed that the freeze-melt method was not selective for the removal of chemical oxygen demand (COD), total organic carbon (TOC), ammonia-nitrogen (NH3-N) and total phosphorus (TP). The removal rate of contaminants was positively correlated with freezing temperature and negatively correlated with freezing duration, and the slower the growth rate of ice, the higher the purity of ice. When the compressed leachate was frozen at −15 °C for 42 h, the removal rates of COD, TOC, NH3-N and TP were 60.00%, 58.40%, 56.89% and 55.34%, respectively. Contaminants trapped in ice were removed during the melting process, especially in the early stages of melting. The divided melting method was more beneficial than the natural melting method in removing contaminants during the initial stage of melting, which contributes to the reduction of produced water losses. This study provides a new idea for the treatment of small amounts of highly concentrated leachate generated by compression facilities distributed in various corners of the city.

The microalgae-based wastewater treatment system coupled with Cerium: A potential way for energy saving and microalgae boost.

The microalgae-based system attracts more attention in wastewater treatment for high quality effluent, low carbon emission, and resource utilization. Light is the key factor for algae growth, but the light masking in sewage will cause low efficiency of the system. This study designed laboratory scale experiments with Chlorella to investigate the influence of cerium on the nutrient removal by algae wastewater treatment system under different light intensities. The best removal rates of NH4-N, TP, and COD were 72.43%, 88.87%, and 68.08% under 50µmol/(m 2·s) light intensity and 1mg/L Ce. Low concentration of Ce could activate protein synthesis, electron transfer, and antioxidase, while excessive Ce might cause toxicity which could be relieved by strong light for energy supply and further activating superoxide dismutase (SOD) and catalase (CAT). Comparing to other similar experiences, this system reached an equal or greater performance on nutrients removal with better efficiency in light utilization. It might provide a new idea for microalgae-based system development.