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1.
Integration of wastewater treatment with algae cultivation is one of the promising ways to achieve an economically viable and environmentally sustainable algal biofuel production on a commercial scale. This study focused on pilot-scale algal biomass production system development, cultivation process optimization, and integration with swine manure wastewater treatment. The areal algal biomass productivity for the cultivation system that we developed ranged from 8.08 to 14.59 and 19.15–23.19 g/m2?×?day, based on ash-free dry weight and total suspended solid (TSS), respectively, which were higher than or comparable with those in literature. The harvested algal biomass had lipid content about 1.77–3.55 %, which was relatively low, but could be converted to bio-oil via fast microwave-assisted pyrolysis system developed in our lab. The lipids in the harvested algal biomass had a significantly higher percentage of total unsaturated fatty acids than those grown in lab conditions, which may be attributed to the observed temperature and light fluctuations. The nutrient removal rate was highly correlated to the biomass productivity. The NH3-N, TN, COD, and PO4-P reduction rates for the north-located photo-bioreactor (PBR-N) in July were 2.65, 3.19, 7.21, and 0.067 g/m2?×?day, respectively, which were higher than those in other studies. The cultivation system had advantages of high mixotrophic growth rate, low operating cost, as well as reduced land footprint due to the stacked-tray bioreactor design used in the study.  相似文献   

2.
Efforts were made to assess the efficiency of an anaerobic filter packed with porous floating ceramic media and to identify the optimum operational condition of anaerobic filter as a pretreatment of swine wastewater for the subsequent biological removal of nitrogen and phosphorus. A stepwise decrease in hydraulic retention time (HRT) and an increase in organic loading rate (OLR) were utilized in an anaerobic filter reactor at mesophilic temperature (35°C). The optimum operating condition of the anaerobic filter was found to be at an HRT of 1 d. A soluble chemical oxygen demand (COD) removal efficiency of 62% and a total suspended solids removal efficiency of 39% at an HRT of 1 d were achieved with an OLR of 16.0 kg total COD/(m3·d), respectively. The maximum methane production rate approached 1.70 vol of biogas produced per volume of reactor per day at an HRT of 1 d. It was likely that the effluent COD/total Kjeldahl nitrogen ratio, of 22, the COD/total phosphorous ratio of 47, and the high effluent alkalinity >2500 mg/L as CaCO3 of the anaerobic filter operated at an HRT of 1 d was adequate for the subsequent biological removal of nitrogen and phosphorus.  相似文献   

3.
A sequencing batch reactor (SBR) applying partial nitritation for reject water treatment was operated for 330 days at a laboratory scale. The system was repeatedly exposed to sudden temperature drops from 24 to 17 °C. The nitrogen loading rate (NLR) was increased incrementally from 0.4 to 1.5 kg/(m3 day) with the aim to evaluate temperature stability of the process at different NLR value. Total nitrite nitrogen (TNIIIN) represented 94–99% of oxidised nitrogen in the effluent throughout the entire operation of the reactor. It was found that the pH profile during the SBR cycle, nitrogen removal efficiency and concentration of N-species in the effluent did not show significant changes following temperature decreases occurring within the entire applied range of the NLR. Simultaneously, the nitrogen removal rate increased proportionally with the NLR where the nitrogen oxidation efficiency reached 48–58% regardless of actual temperature and NLR. These observations clearly demonstrate the temperature stability of applied partial nitritation system during the tested temperature fluctuations.  相似文献   

4.
This article summarizes the results obtained during the laboratory and pilot development of integrated biologic and physicochemical treatment and reuse of diluted pig manure streams. The application of a straw filter was an effective means to separate the solid and liquid fractions of raw wastewater and resulted in the removal of a significant part of the dry matter, total nitrogen, and phosphorus (65, 27, and 32%, respectively). From the filtrate generated, 60–80% of the total chemical oxygen demand (COD) was removed in an upflow anaerobic sludge bed reactor operating at 15–30°C. Ammonia was efficiently eliminated (>99%) from the anaerobic effluents using Ural laumantite as an ion exchanger. However, the nitrogen-content of the zeolite was too low to consider this method of ammonia removal economically feasible. The phosphate precipitation block, consisting of stripper of CO2 and fluidized-bed crystallizator, was able to decrease the concentration of soluble phosphate in the anaerobic effluents up to 7–15 mg of phosphate/L. The application of aerobic/anoxic biofilter as a sole polishing step was acceptable from an aesthetic point of view (the effluents were transparent and almost colorless and odorless) and elimination of biochemical oxygen demand (the resting COD was hardly biodegradable). However, the effluent nutrient concentrations (especially nitrogen) were far from the current standards for direct discharge of treated wastewater. We discuss the approaches for further improvement of effluent quality. Finally, we provide an outline of a full-scale system that partially implements the laboratory- and pilot-scale results obtained.  相似文献   

5.
Food waste and municipal wastewater are promising feedstocks for microbial lipid biofuel production, and corresponding production process is to be developed. In this study, different oleaginous yeast strains were tested to grow in hydrolyzed food waste, and growths of Cryptococcus curvatus, Yarrowia lipolytica, and Rhodotorula glutinis in this condition were at same level as in glucose culture as control. These strains were further tested to grow in municipal primary wastewater. C. curvatus and R. glutinis had higher production than Y. lipolytica in media made from primary wastewater, both with and without glucose supplemented. Finally, a process was tested to grow C. curvatus and R. glutinis in media made from food waste and municipal wastewater, and the effluents from these processes were further treated with yeast culture and phototrophic algae culture; 1.1 g/L C. curvatus and 1.5 g/L R. glutinis biomass were further produced in second-step yeast cultures, as well as 1.53 and 0.58 g/L Chlorella sorokiniana biomass in phototrophic cultures. The residual nitrogen concentrations in final effluents were 33 mg/L and 34 mg/L, respectively, and the residual phosphorus concentrations were 1.5 and 0.6 mg/L, respectively. The lipid contents in the produced biomass were from 18.7% to 28.6%.  相似文献   

6.
施云芬  魏冬雪 《化学通报》2014,77(6):562-567
为了探讨移动床生物膜反应器中不同填料对废水脱氮除磷效果的影响,采用碳纤维球和聚乙烯塑料两种不同悬浮填料进行对比试验。在不同运行条件下,分别测定氨氮、总氮、总磷、COD等指标,对比挂膜和脱氮除磷效果。结果表明,碳纤维球填料挂膜速度快,在不同运行条件下均比聚乙烯塑料填料对COD、NH4+-N、TN、TP等的去除效果好,去除率分别可达91.2%、98.0%、77.5%、68.1%。这说明比表面积大、孔隙率高的填料挂膜更快,挂膜量更多,更有利于实现同时生物脱氮除磷。  相似文献   

7.
An anaerobic sequencing batch biofilm reactor (AnSBBR—total volume 7.5 L; liquid volume 3.6 L; treated volume per cycle 1.5 L) treated sucrose-based wastewater to produce biohydrogen (at 30 °C). Different applied volumetric organic loads (AVOL of 9.0, 12.0, 13.5, 18.0, and 27.0 kg COD m?3 day?1), which were varied according to the influent concentration (3,600 and 5,400 mg COD L?1) and cycle length (4, 3, and 2 h), have been used to assess the following parameters: productivity and yield of biohydrogen per applied and removed load, reactor stability, and efficiency. The removed organic matter (COD) remained stable and close to 18 % and carbohydrates (sucrose) uptake rate remained between 83 and 97 % during operation. The decrease in removal performance of the reactor with increasing AVOL, by increasing the influent concentration (at constant cycle length) and decreasing the cycle lengths (at constant influent concentrations), resulted in lower conversion efficiencies. Under all conditions, when organic load increased there was a predominance of acetic, propionic, and butyric acid as well as ethanol. The highest concentration of biohydrogen in the biogas (24–25 %) was achieved at conditions with AVOL of 12.0 and 13.5 kg COD m?3 day?1, the highest daily production rate (0.139 mol H2?day?1) was achieved at AVOL of 18.0 kg COD m?3 day?1, and the highest production yields per removed and applied load were 2.83 and 3.04 mol H2?kg SUC?1, respectively, at AVOL of 13.5 kg COD m?3 day?1. The results indicated that the best productivity tends to occur at higher organic loads, as this parameter involves the “biochemical generation” of biogas, and the best yield tends to occur at lower and/or intermediate organic loads, as this parameter involves “biochemical consumption” of the substrate.  相似文献   

8.
Multi-phase anaerobic reactor for H2 and CH4 production from paperboard mill wastewater was studied. The reactor was operated at hydraulic retention times (HRTs) of 12, 18, 24, and 36 h, and organic loading rates (OLRs) of 2.2, 1.5, 1.1, and 0.75 kg chemical oxygen demand (COD)/m3 day, respectively. HRT of 12 h and OLR of 2.2 kg COD/m3 day provided maximum hydrogen yield of 42.76?±?14.5 ml/g CODremoved and volumetric substrate uptake rate (?rS) of 16.51?±?4.43 mg COD/L h. This corresponded to the highest soluble COD/total COD (SCOD/TCOD) ratio of 56.25?±?3.3 % and the maximum volatile fatty acid (VFA) yield (YVFA) of 0.21?±?0.03 g VFA/g COD, confirming that H2 was mainly produced through SCOD conversion. The highest methane yield (18.78?±?3.8 ml/g CODremoved) and ?rS of 21.74?±?1.34 mgCOD/L h were achieved at an HRT of 36 h and OLR of 0.75 kg COD/m3 day. The maximum hydrogen production rate (HPR) and methane production rate (MPR) were achieved at carbon to nitrogen (C/N) ratio of 47.9 and 14.3, respectively. This implies the important effect of C/N ratio on the distinction between the dominant microorganism bioactivities responsible for H2 and CH4 production.  相似文献   

9.
Many lab-scale studies have been carried out regarding the effect of feed strategy on the performance of anaerobic sequencing batch reactors (ASBR); however, more detailed pilot-scale studies should be performed to assess the real applicability of this type of operation. Therefore, the objective of this work was to assess the effect of feed strategy or fill time in a 1-m3 mechanically stirred pilot-scale sequencing batch reactor, treating 0.65 m3 sanitary wastewater in 8-h cycles at ambient temperature. Two reactor configurations were used: one containing granular biomass (denominated ASBR) and the other immobilized biomass on polyurethane foam as inert support (denominated anaerobic sequencing batch biofilm reactor (AnSBBR)). The reactors were operated under five distinct feed strategies, namely: typical batch and fed-batch for 25%, 50%, 75%, and 100% of the cycle length. Stirring frequency in the ASBR was 40 rpm with two flat-blade turbine impellers and 80 rpm in the AnSBBR with two helix impellers. The results showed that both the ASBR and AnSBBR when operated under typical batch, fed-batch for 50% and 75% of the cycle length, presented improved organic matter removal efficiencies, without significant differences in performance, thus showing important operational flexibility. In addition, the reactors presented operation stability under all conditions.  相似文献   

10.
The objective of the present study was to evaluate the nutrient removal efficiency and the physiological responses in terms of growth, biochemical composition and photosynthetic activity of the autochthonous freshwater algal strain Desmodesmus communis. Microalgae were grown in a primary municipal effluent under different hydraulic retention times (HRTs) and in a two-phases process using both primary and secondary wastewater effluents. Semi-continuous cultures were operated for 7 day at 5-, 3- and 1.5-day HRT and the different dilution rate showed a greater influence on the biomass composition and nutrient removal efficiency. Removal of N-NH3 and P-PO4 was over 99 % and the highest accumulation of polysaccharides (57.2 wt.%) was obtained at high HRT (5 day); the maximum content of proteins (26.9 wt.%) was achieved at 1.5-day HRT, even if, under this condition, a clear inefficiency in terms of ammonia removal was observed. Moreover the accumulation of N-NH3 occurring at 1.5-day HRT caused the decrease of the photosynthetic response in terms of efficiency of light capture (α) and relative electron transport rate (rETR), both parameters extracted from the rapid light curves (RLC) measurements. No significant differences were observed for the total fatty acids (TFAs), with a content of 2–3.5 wt.% for each HRT condition. On the other hand, in the two-phases process, when a nutrient deprivation condition was induced by diluting the culture with the secondary wastewater effluent, the algal cells accumulated TFAs, achieving a maximum content of 9.7 wt.% and a great increment in terms of biomass (1.64?±?0.02 g L?1) due to the ability of this algal strain to accumulate intracellular N. The wide and accurate investigation of the different aspects related to the whole process represents a relevant point of novelty in this research field and suggests the operational conditions for the start-up of an open pond system for wastewater treatment and biomass production for further applications.  相似文献   

11.
In enhanced biological phosphorus removal (EBPR) process, phosphorus (P) in wastewater is removed via wasted sludge without actual recovery. A novel approach to realize phosphorus recovery with special external chemical oxygen demand (COD) addition in EBPR process was proposed. During the new operating approach period, it was found that (1) no phosphorus was detected in the effluent; (2) with an external addition of 10 % of influent COD amount, 79 % phosphorus in the wastewater influent was recovered; (3) without wasted sludge, the MLVSS concentration in the system increased from 2,010 to 3,400 mg/L and kept stable after day 11 during 24-day operating period. This demonstrates that the novel approach is feasible to realize phosphorus recovery with no wasted sludge discharge in EBPR process. Furthermore, this approach decouples P removal and sludge age, which may enhance the application of membrane bioreactor for P removal.  相似文献   

12.
《中国化学快报》2023,34(4):107707
Removal and recovery of phosphorus (P) from wastewater is of great importance to addressing the challenges of eutrophication and phosphorus shortage. The P removal and recovery performance of conventional electrochemical precipitation approach was constrained by the limited mass transfer rate. Herein, a cathodic membrane filtration (CMF) reactor was developed using Ti/SnO2-Sb anode and titanium mesh cathodic membrane module to achieve efficient removal and recovery of P in wastewater. Compared with the flow-by mode, the CMF system in the flow-through mode exhibited excellent P removal performance due to the markedly enhanced mass transfer. At the current density of 4 A/m2, membrane flux of 16.6 L m?2 h?1, and Ca/P molar ratio of 1.67, the removal efficiency of P was 96.2% and the energy consumption was only 45.7 kWh/kg P. The local high pH of cathode surface played a vital role in P removal, which substantially accelerated the nucleation of calcium phosphate (CaP). Based on the crystalline and morphological characterization of the precipitates, the hydroxyapatite was the most stable crystalline phase of CaP, which was transformed from intermediate phases (such as dicalcium phosphate and amorphous calcium phosphate). This study paves the way for applying electrochemical membrane filtration system for P removal and recovery from wastewater.  相似文献   

13.
《Electroanalysis》2018,30(9):2145-2152
A novel membrane‐less microbial fuel cell (ML‐MFC) which used the baffles instead of the ion exchange membrane (IEM) was developed for ammonium‐containing wastewater treatment and electricity generation. By means of installing an ideal nitrifying unit between the anodic and cathodic chamber, the novel ML‐MFC accomplished organics degradation and nitrogen removal without additional loop. The removal efficiencies of COD, NH4+−N and TN achieved 97.07±0.47 %, 91.76±3.32 % and 87.66±1.59 %, respectively. Meanwhile, the effluent pH was near neutral and turbidity was quite low. In addition, the maximum power density of 1.007±0.032 W/m3 was obtained. Combined with the analysis of microbial community, electroactive bacteria (EAB) Desulfovibrio, Comamonas and Thiobacillus were enriched in biofilm. Considering the superior effluent quality and the promising energy potential, the novel ML‐MFC has good application prospects in efficient and sustainable wastewater treatment.  相似文献   

14.
An investigation was performed regarding the application of a mechanically stirred anaerobic sequencing batch biofilm reactor containing immobilized biomass on inert polyurethane foam (AnSBBR) to the treatment of soluble metalworking fluids to remove organic matter and produce methane. The effect of increasing organic matter and reactor fill time, as well as shock load, on reactor stability and efficiency have been analyzed. The 5-L AnSBBR was operated at 30?°C in 8-h cycles, agitation of 400 rpm, and treated 2.0 L effluent per cycle. Organic matter was increased by increasing the influent concentration (500, 1,000, 2,000, and 3,000 mg chemical oxygen demand (COD)/L). Fill times investigated were in the batch mode (fill time 10 min) and fed-batch followed by batch (fill time 4 h). In the batch mode, organic matter removal efficiencies were 87%, 86%, and 80% for influent concentrations of 500, 1,000, and 2,000 mgCOD/L (1.50, 3.12, and 6.08 gCOD/L.d), respectively. At 3,000 mgCOD/L (9.38 gCOD/L.d), operational stability could not be achieved. The reactor managed to maintain stability when a shock load twice as high the feed concentration was applied, evidencing the robustness of the reactor to potential concentration variations in the wastewater being treated. Increasing the fill time to 4 h did not improve removal efficiency, which was 72% for 2,000 mgCOD/L. Thus, gradual feeding did not improve organic matter removal. The concentration of methane formed at 6.08 gCOD/L was 5.20 mmolCH4, which corresponded to 78% of the biogas composition. The behavior of the reactor during batch and fed-batch feeding could be explained by a kinetic model that considers organic matter consumption, production, and consumption of total volatile acids and methane production.  相似文献   

15.
In this work, capability of the green microalga (MA), Chlorella vulgaris, in treating synthetic anaerobic effluent of municipal wastewater was investigated. While pure C. vulgaris (100 % MA) provided maximum soluble chemical oxygen demand (sCOD) and N???NH 4 + removal efficiencies of 27 and 72 % respectively, addition of activated sludge (AS) to MA in different mass ratios (91, 80, 66.7, 9 % MA) improved wastewater treatment efficiency. Thus giving maximum sCOD and N???NH 4 + removal efficiencies 85 and 86.3 % (for MA/AS?=?10/1), respectively. Utilizing AS without C. vulgaris, for treating the synthetic wastewater resulted in 87 % maximum sCOD and 42 % maximum N???NH 4 + removal efficiencies. Furthermore, algal growth and specific growth rates were measured in the systems with microalga as the dominant cellular population. As a result, faster algal growth was observed in mixed systems. Specific growth rate of C. vulgaris was 0.14 (day?1) in 100 % MA and 0.39 (day?1) in 80 % MA. Finally, data gathered by online measurement of dissolved oxygen indicate that algae-activated sludge mixture improves photosynthetic activity of examined microalga strain during anaerobic effluent treatment.  相似文献   

16.
The denitrification of municipal sludge was improved by combining biofilm process with the electro-chemical effect in a single novel reactor. Experiments in this reactorl-electric current 60 mA, hydraulic reten-tion time (HRTs) 6.0h] showed that the removal of CODcr, ammonia nitrogen and total nitrogen in the biofilm-electrode reactor were 2.5%, 1.2%, 14.9%, respectively, higher than those in a traditional biofilm reactor.  相似文献   

17.
In order to assess the effects of the surface hydrophilicity of supports on the biofilm formation and evaluate the performance of completely autotrophic nitrogen removal over nitrite (CANON) process in a sequencing batch biofilm reactor (SBBR), unmodified activity carbon fibers (ACFs) and ACFs hydrophilic modified by heat treatment were used as supports. CANON process was initiated in a SBBR from conventional activated sludge. An operation temperature of 32 ± 2 °C, dissolved oxygen (DO) level at 1.5 mg L−1 and free ammonia (FA) concentration with 3.98–15.93 mg L−1 were maintained in the SBBR. Fourier transform infrared (FT-IR) spectra and Boehm’s neutralizing titration exhibited that modified ACFs had more oxygen-containing groups than unmodified ACFs. Larger biofilm growth on the modified surfaces examined by scanning electron microscopy and biofilm’s total dry weight, and the biofilm on the modified surfaces were more active, compared with those on the unmodified surfaces. This study demonstrates the hydrophilic-modified ACFs have better biological affinity than unmodified ACFs. Maximal total nitrogen removal rate of 0.088 k g N m−3 day−1 was achieved for the CANON process on day 80, indicating the CANON process was successfully started up. Apart from supports, the strategies of DO supplying and controlling FA concentration were also keys in starting up the CANON process within a shorter period.  相似文献   

18.
A mechanically stirred anaerobic sequencing batch reactor containing anaerobic biomass immobilized on polyurethane foam cubes, treating low-strength synthetic wastewater (500 mg COD L?1), was operated under different operational conditions to assess the removal of organic matter and sulfate. These conditions were related to fill time, defined by the following feed strategies: batch mode of 10 min, fed-batch mode of 3 h and fed-batch mode of 6 h, and COD/[SO4 2?] ratios of 1.34, 0.67, and 0.34 defined by organic matter concentration of 500 mg COD L?1 and sulfate concentrations of 373, 746, and 1,493 mg SO4 2? L?1 in the influent. Thus, nine assays were performed to investigate the influence of each of these parameters, as well as the interaction effect, on the performance of the system. The reactor operated with agitation of 400 rpm, total volume of 4.0 L, and treated 2.0 L synthetic wastewater in 8-h cycles at 30?±?1°C. During all assays, the reactor showed operational stability in relation to the monitored variables such as COD, sulfate, sulfide, sulfite, volatile acids, bicarbonate alkalinity, and solids, thus demonstrating the potential to apply this technology to the combined removal of organic matter and sulfate. In general, the results showed that the 3-h fed-batch operation with a COD/[SO4 2?] ratio of 0.34 presented the best conditions for organic matter removal (89%). The best efficiency for sulfate removal (71%) was accomplished during the assay with a COD/[SO4 2?] ratio of 1.34 and a fill time of 6 h. It was also observed that as fill time and sulfate concentration in the influent increased, the ratio between removed sulfate load and removed organic load also increased. However, it should be pointed out that the aim of this study was not to optimize the removal of organic matter and sulfate, but rather to analyze the behavior of the reactor during the different feed strategies and applied COD/[SO4 2?] ratios, and mainly to analyze the interaction effect, an aspect that has not yet been explored in the literature for batch reactors.  相似文献   

19.
We report on the development of an electrochemical sensor based on electrodepositing zinc oxide on multiwalled carbon nanotube-modified glassy carbon electrode for the detection of caffeine in pharmaceutical wastewater effluents. The measurements were carried out using cyclic voltammetry, electrochemical impedance spectroscopy, chronoamperometry and differential pulse voltammetry (DPV). DPV measurements showed a linear relationship between oxidation peak current and concentration of caffeine in 0.1 M HClO4 (pH 1.0) over the concentration range 0.00388–4.85 mg/L and a detection limit of 0.00194 mg/L. The diffusion coefficient and Langmuir adsorption constant for caffeine were calculated to be 3.25 × 10?6 cm2 s?1 and 1.10 × 103 M?1, respectively. The sensor showed satisfactory results when applied to the detection of caffeine in wastewater effluents.  相似文献   

20.
Considering the importance of methylotrophs in industrial wastewater treatment, focus of the present study was on utilization of a methylotrophic bacterial consortium as a microbial seed for biotreatment of a variety of industrial effluents. For this purpose, a mixed bacterial methylotrophic AC (Ankleshwar CETP) consortium comprising of Bordetella petrii AC1, Bacillus licheniformis AC4, Salmonella subterranea AC5, and Pseudomonas stutzeri AC8 was used. The AC consortium showed efficient biotreatment of four industrial effluents procured from fertilizer, chemical and pesticide industries, and common effluent treatment plant by lowering their chemical oxygen demand (COD) of 950–2000 mg/l to below detection limit in 60–96 h in 6-l batch reactor and 9–15 days in 6-l continuous reactor. The operating variables of wastewater treatment, viz. COD, BOD, pH, MLSS, MLVSS, SVI, and F/M ratio of these effluents, were also maintained in the permissible range in both batch and continuous reactors. Therefore, formation of the AC consortium has led to the development of an efficient microbial seed capable of treating a variety of industrial effluents containing pollutants generated from their respective industries.  相似文献   

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