Biotreatment of Industrial Wastewater by Selected Algal‐Bacterial Consortia

A new approach for remediation processes in highly polluted environments is presented. The efficiency of algal‐bacterial associations for the remediation of industrial wastewater of a pond in Samara, Russia, was investigated. After screening of algae and bacteria for the resistance to the wastewater the following strains were selected: the algal strains Chlorella sp. ES‐13, Chlorella sp. ES‐30, Scenedesmus obliquus ES‐55, several Stichococcus strains (ES‐19, ES‐85, ES‐86, ES‐87, ES‐88), and Phormidium sp. ES‐90 and the bacterial strains Rhodococcus sp. Ac‐1267, Kibdelosporangium aridum 754 as well as two unidentified bacterial strains (St‐1, St‐2) isolated from the collector pond. All the strains listed above were immobilized onto various solid carriers (capron fibers for algae; ceramics, capron and wood for bacteria) and used for biotreatment in a pilot installation. The results showed that the selected algae and bacteria formed stable consortia during the degradation of the waste, which was demonstrated for the first time for the green alga Stichococcus. Stichococcus and Phormidium cells attached to capron fibers with the help of slime and formed a matrix. This matrix fixed the bacteria and eukaryotic algae and prevented them from being washed off. A significant decrease in the content of the pollutants was observed: phenols were removed up to 85 %, anionic surface active substances (anionic SAS) up to 73 %, oil spills up to 96 %, copper up to 62 %, nickel up to 62 %, zinc up to 90 %, manganese up to 70 %, and iron up to 64 %. The reduction of the biological oxygen demand (BOD₂₅) and the chemical oxygen demand COD amounted to 97 % and 51 %, respectively.     

Combined Two‐Stage Xanthate Processes for the Treatment of Copper‐Containing Wastewater

Heavy metal removal is mainly conducted by adjusting the wastewater pH to form metal hydroxide precipitates. However, in recent years, the xanthate process with a high metal removal efficiency, attracted attention due to its use of sorption/desorption of heavy metals from aqueous solutions. In this study, two kinds of agricultural xanthates, insoluble peanut‐shell xanthate (IPX) and insoluble starch xanthate (ISX), were used as sorbents to treat the copper‐containing wastewater (Cu concentration from 50 to 1,000 mg/L). The experimental results showed that the maximum Cu removal efficiency by IPX was 93.5 % in the case of high Cu concentrations, whereby 81.1 % of copper could rapidly be removed within one minute. Moreover, copper‐containing wastewater could also be treated by ISX over a wide range (50 to 1,000 mg/L) to a level that meets the Taiwan EPA's effluent regulations (3 mg/L) within 20 minutes. Whereas IPX had a maximum binding capacity for copper of 185 mg/g IPX, the capacity for ISX was 120 mg/g ISX. IPX is cheaper than ISX, and has the benefits of a rapid reaction and a high copper binding capacity, however, it exhibits a lower copper removal efficiency. A sequential IPX and ISX treatment (i.e., two‐stage xanthate processes) could therefore be an excellent alternative. The results obtained using the two‐stage xanthate process revealed an effective copper treatment. The effluent (C_e) was below 0.6 mg/L, compared to the influent (C₀) of 1,001 mg/L at pH = 4 and a dilution rate of 0.6 h^–1. Furthermore, the Cu‐ISX complex formed could meet the Taiwan TCLP regulations, and be classified as non‐hazardous waste. The xanthatilization of agricultural wastes offers a comprehensive strategy for solving both agricultural waste disposal and metal‐containing wastewater treatment problems.     

Microbial Processes of Heavy Metal Removal from Carbon‐Deficient Effluents in Constructed Wetlands

This paper reviews the main microbial processes involved when toxic metals are removed from wastewater in constructed wetlands. Microbial activity is thought to play a key role in the detoxification of these metals. The paper concentrates on the microbial processes which affect the mobility, the toxicity and bioavailability of metals, namely biosorption, metal sulfide precipitation by sulfate reducers, redox transformations, and methylation, as well as microbe‐plant interactions. These reactions result in either the precipitation and accumulation of metals in wetland soils, or their volatilization and emission into the atmosphere. The possibilities of optimizing the microbially mediated reactions for the development of wetland technology are discussed as a long‐term metal retention strategy.     

Dynamic Model for the Adsorption in a Multibed Three‐Phase Fluidization Column Applied to Wastewater Biological Treatment

It is proposed a dynamic model for adsorption of NH₄⁺ ions from ammonia waters on volcanic tuff in a 10‐bed three‐phase (air – ammonia waters – volcanic tuff) fluidization column. The model consists in the nonstationary material balance differential equations. For each layer the ideal well‐mixing conditions are considered. The effluent ammonia ion concentrations, corresponding to each layer, have been measured at several time values in a laboratory‐scale column. The absolute relative mean error between the calculated and measured values of ammonia ion concentrations into liquid phase for all layers and times is 6.65 %, being in the order of magnitude of experimental errors.     

Removal of Selected Metals from Wastewater Using a Constructed Wetland

Removal of selected metals from municipal wastewater using a constructed wetland with a horizontal subsurface flow was studied. The objective of the work was to determine the efficiency of Cu, Zn, Ni, Co, Sr, Li, and Rb removal, and to describe the main removal mechanisms. The highest removal efficiencies were attained for zinc and copper (89.8 and 81.5%, respectively). It is apparently due to the precipitation of insoluble sulfides (ZnS, CuS) in the vegetation bed where the sulfate reduction takes place. Significantly lower removal efficiencies (43.9, 27.7, and 21.5%) were observed for Li, Sr, and Rb, respectively. Rather, low removal efficiencies were also attained for Ni and Co (39.8 and 20.9%). However, the concentrations of these metals in treated water were significantly lower compared to Cu and Zn (e.g., 2.8 ± 0.5 and 1.7 ± 0.3 μg/l for Ni at the inflow and outflow from the wetland compared to 27.6 ± 12.0 and 5.1 ± 4.7 μg/l obtained for Cu, respectively). The main perspective of the constructed wetland is the removal of toxic heavy metals forming insoluble compounds depositing in the wetland bed. Metal uptake occurs preferentially in wetland sediments and is closely associated with the chemism of sulfur and iron.     

Removal of Anionic Surfactants from Wastewater Using a Constructed Wetland

Removal of anionic surfactants from municipal wastewater using a constructed wetland with a horizontal subsurface flow was studied in 2007 and 2008. Extraction spectrophotometry with methylene blue served to determine the analyte concentrations in individual samples. The anionic surfactant‐removal efficiency depended on actual conditions, mostly the treated water flow intensity, its temperature, and a redox‐potential gradient in the longitudinal profile of the wetland bed. It increased with decreasing inflow and increasing temperature. The average efficiency was 83.7% in 2007 and 81.7% in 2008; however, values higher than 85% were often determined during the summer period. On the other hand, the efficiencies were usually lower than 80% in winter, especially in periods with intensive precipitation and inflows. The average concentration of anionic surfactants in water taken at the outflow was lower than 0.65 mg/l (expressed as sodium dodecyl sulfate). The most significant fraction of anionic surfactants (almost 50%) was degraded at the beginning (1 m from the inflow zone) of the wetland bed. The rhizosphere aeration via the vegetation roots strongly supported the anionic‐surfactant removal.     

Phosphate Removal from Wastewaters: A Novel Approach

The conditions necessary for the establishment and maintenance of Enhanced Biological Phosphate Removal (EBPR) from wastewaters are discussed in the light of our inability to achieve levels of EBPR from artificial sewage in a laboratory‐scale system. Adequate levels of P removal and polyP accumulation by sludge biomass could only be restored by the imposition of stringent anaerobiosis (Eh < –120 mV) and by increasing the short chain fatty acid composition of the influent. Subsequent laboratory‐scale investigations into several possible alternative strategies to achieve enhanced levels of P removal and polyP accumulation from artificial sewage medium indicated that a reduction in the operational pH of the system to approximately 5.5 could achieve comparable levels of P removal under fully‐aerobic conditions. Acid stimulated P uptake and polyP formation might serve as the basis of novel alternative technologies for eutrophication control at wastewater treatment facilities.     

Chromium Removal from Aqueous System and Industrial Wastewater by Agricultural Wastes

This study involved the development of formaldehyde-treated, deseeded sunflower head waste–based biosorbent (FSH) for the biosorption of Cr(VI) from aqueous solution and industrial wastewater. Batch-mode experiments were conducted to determine the kinetics, sorption isotherms, effect of pH, initial Cr(VI) concentration, biosorbent dose, and contact time. The results demonstrated that FSH can sequester Cr(VI) from the aqueous solution. The maximum sorption occurred at pH = 2.0, biosorbent dose = 4.0 g/L, concentration of 100 mg/L at 25°C at 180 rpm after 2 h contact time. The FSH had an adsorption capacity of 7.85 mg/g for Cr(VI) removal at pH 2.0. The rate of adsorption was rapid, and equilibrium was attained within 2 h. The equilibrium sorption data fitted the Langmuir isotherm model, which was further confirmed by the chi-square test.     

Generating “Tide” in Pilot‐Scale Constructed Wetlands to Enhance Agricultural Wastewater Treatment

The operation of tidal flow was studied using a pilot‐scale system treating high strength piggery wastewater. Located on a farm in Staffordshire, UK, the system consisted of five wetland treatment stages vegetated with common reeds of Phragmites australis. Wastewater samples were collected from the inlet and outlet of each stage and analyzed for BOD₅, COD, NH₄‐N, NO₃‐N, NO₂‐N, SS, PO₄‐P and pH. Average hydraulic and organic loadings on the system were 0.12 m³/m² d and 240 g BOD/m² d, respectively, which is considerably higher than the typical loadings on conventional subsurface flow systems. On average, BOD₅ and COD were reduced by 82 % and 80 % from initial concentrations of 2000 mg/L and 2750 mg/L, respectively, across the whole system. The first‐order kinetics constant for BOD₅ removal (K_BOD in m/d) in this tidal flow system is approximately 2.5 times the rate constant obtainable in a typical horizontal flow system, demonstrating a more efficient removal of organic matter in tidal flow wetlands. The overall efficiency of the system was found to increase with time before stabilizing towards the end of a start‐up period. Straight‐line correlations were established between the loading and removal of BOD₅ and COD. Contributions by individual stages to the overall treatment were analyzed. SEM images of wetland media demonstrated the formation of biofilms and microbial activities inside the matrices of the wetland system, which accounted for the degradations of organic pollutants.     

Prediction of the Metabolic Activity of a Mixed Bacillus Culture during the Biodegradation of Wastewater from the Potato Industry

The advantages of the analysis of electrical impedance changes for the prediction of the metabolic activity of mixed Bacillus cultures used for high temperature industrial wastewater utilization are demonstrated. The primary aim of this study was to investigate the possibilities of a fast assessment of the biodegradative capabilities of microorganisms, their requirements regarding the medium composition as well as the inhibiting effect of high‐strength (i.e., highly concentrated) wastewaters on microbial growth. Four mixed Bacillus cultures were cultivated at 45 and 55 °C on two kinds of wastewater from the potato starch industry. The course of changes in the electrical impedance during the cultivation of the bacteria in the examined wastewaters was described by the mathematical Gompertz model. Three kinetics parameters (maximum rate of impedance changes, I_max; the time necessary to reach, I_max, T_I; and the duration of the lag phase, λ) were proposed for the statistical analysis of the bacterial metabolic activity. The temperature of the biodegradation process and the type and strength of the wastewater significantly influenced the microbial metabolic activity of the mixed bacterial cultures used. Monitoring of the impedance changes, caused by microbial metabolism, and its proposed mathematical specification allowed for predicting the dynamics of the microbiological degradation of wastewater and estimating the inhibiting effects of these media on the microorganisms.     

Upgrading of Existing Municipal Wastewater Treatment Plants with the “Non‐Conventional Low MLSS MBR Technology”

In the future, upgrading of existing wastewater treatment plants (wwtps) will be more important than the erection of entirely new plants, as most of the plants necessary in Germany already exist. Thus far, membrane bioreactor (MBR) technology is not used as an alternative for plant upgrading in Germany. However, at several locations the preconditions indicate that the application of the MBR technology for upgrading of plants may be favorable. These preconditions include the need for a substantial enlargement of the aeration tank volume and/or the need to improve the efficiency of the final sedimentation tanks, and also require that the existing tanks be in a good state, so that the tanks can be used in the future. The relevant preconditions and the basic upgrading concept using the MBR technology were presented earlier. Depending on the local preconditions regarding the existing tank volume, a specific aspect of this application can be an operation mode using “non‐conventional low MLSS (mixed liquor suspended solids) concentrations” (5 kg MLSS/m³ through 7 kg MLSS/m³) due to the amount of the existing tank volume. Two research projects were carried out covering the operation of five pilot plants on a cubic meter scale to demonstrate the feasibility of this kind of MBR process. This paper presents the core results of this research work.     

Urea increases fed‐batch growth and γ‐linolenic acid production of nutritionally valuable Arthrospira (Spirulina) platensis cyanobacterium

In this article we investigate the simultaneous influence of feeding time and amount of urea added as a nitrogen source on the fed‐batch growth and composition of Arthrospira (Spirulina) platensis. Cultivations were performed in 5‐L minitanks at constant temperature (25°C) and light intensity (42 μmol photons/m²s), using exponentially increasing rate of urea addition, and varying the above independent variables in the ranges 9–15 days and 4.6–12.1 mM, respectively. Special emphasis was placed on the content of added high value fatty acids (e.g., γ‐linolenic acid) of concern for the food industry. To this purpose, a 2²‐plus star central composite design was employed, and maximum cell concentration, cell productivity, yield of biomass on nitrogen added, protein content and fatty acids profile were evaluated by multiple regression analysis. The highest cell concentration (1759 mg/L) was obtained at feeding time of 14 days and amount of urea per unit reactor volume of 5.8 mM, while the highest contents of γ‐linolenic acid (27.5% of the lipid fraction) and proteins (77.2%) were obtained at 10 and 14 days and 5.8 and 10.8 mM, respectively. The results confirm the possibility of using urea as cheap nitrogen source to culture this nutritionally valuable cyanobacterium.     

Protective Effect of Immobilized Ammonia Oxidizers and Phenol‐degrading Bacteria on Nitrification in Ammonia– and Phenol‐containing Wastewater

Phenol present in wastewaters from various industries has an inhibitory effect on nitrification even at low concentrations. Hence, the biological treatment of wastewater containing both phenol and ammonia involves a series of treatment steps. It is difficult to achieve nitrification capability in an activated sludge system that contains phenol at concentrations above the inhibitory level. Batch treatment of wastewater containing various concentrations of phenol showed that the ammonia oxidation capability of suspended Nitrosomonas europaea cells, an ammonia oxidizer, was completely inhibited in the presence of more than 5.0 mg/L phenol. To protect the ammonia oxidizer from the inhibitory effect of phenol and to achieve ammonia oxidation capability in the wastewater containing phenol at concentrations above the inhibitory level, a simple bacterial consortium composed of an ammonia oxidizer (N. europaea) and a phenol‐degrading bacterial strain (Acinetobacter sp.) was used. Ammonia oxidation did not occur in the presence of phenol at concentrations above the inhibitory level when suspended or immobilized N. europaea and Acinetobacter sp. cells were used in batch treatment. Following the acclimatization of the immobilized cells, accumulation of nitrite was observed, even when the wastewater contained phenol at concentrations above the inhibitory level. These results showed that immobilization was effective in protecting N. europaea cells from the inhibitory effect of phenol present in the wastewater.     

Biosafe Ginseng: A Novel Source for Human Well‐Being

Given the enormous biodiversity in field cultivation, bioengineers were only to look within nature to find new promising phytomolecules or biochemical pathways from plant biofactories. The present review discusses pilot‐scale bioreactor cultivation of adventitious roots of ginseng and the enhanced production of pesticide‐free bioactive phytomolecules. This biotechnological method is described together with a discussion on economic and biosafety aspects. Besides the “classical” tissue culture as a subject of research on ginseng, new developments and efforts in pilot‐scale bioreactor tissue modeling and in the generation of artificial adventitious roots are considered. Additionally, recent progress in the field of medicinal and nutritional roles of adventitious roots produced in a pilot‐scale bioreactor are discussed.     

Occurrence of Pathogenic Free‐Living Amoebae and Bacterial Indicators in a Constructed Wetland Treating Domestic Wastewater from a Single Household

Constructed wetlands are effective wastewater treatment systems because of their ability to remove large amounts of organic matter and pathogens. The goals of this study were to characterize the presence of pathogenic free‐living amoebae and bacterial indicators (total and fecal coliforms), and to ascertain the removal efficiencies of physical and chemical pollutants, in a constructed wetland treating domestic wastewater from a single household. Influent and effluent samples were collected monthly over a ten‐month period for biological, physical and chemical analyses. Thirty‐two species of free‐living amoebae were isolated from the system. The genus Acanthamoeba was the most frequently encountered (59 %) and was removed from the wastewater with the greatest efficiency (80 %). Removal of bacteria was low, the highest removal rates were found in August (4 logarithmic units) and January (3 logarithmic units). The average removal efficiencies of suspended solids, BOD₅ and ammoniacal nitrogen were 71.5 %, 50.6 % and 13.1 %, respectively. The relatively low removal efficiencies of the various bacteriological, physical and chemical parameters suggest that the hydraulic retention time was probably insufficient for optimal treatment to occur. The effluent quality was unacceptable for unrestricted irrigation of crops that are eaten uncooked.     

A Novel Phosphate-Accumulating Bacterium Identified in a Bioreactor for Phosphate Removal from Wastewater

Microbiology - Abstract—Biotechnologies involving phosphate-accumulating organisms, which collect inorganic phosphates from the medium as polyphosphates during cyclic growth under aerobic and...     

Identifying Lowest‐Emission Choices and Environmental Pareto Frontiers for Wastewater Treatment Wastewater Treatment Input‐Output Model based Linear Programming

This article proposes a linear programming model that is based on the wastewater treatment input‐output model (W²IO) to identify the lowest‐emission choice among alternative feasible options for wastewater treatment; this model can be considered as an application of the waste input‐output linear programming model (WIO‐LP) to wastewater issues. Using the data of the Tokyo metropolitan W²IO table, I apply this model to obtain the optimal wastewater treatment options under alternative scenarios. The Pareto frontiers of environmental loads are derived to show the trade‐off relationships among various types of environmental load and the effect of the introduction of high‐temperature incineration of dewatered sludge on the generation of environmental loads. The main conclusion of the study is that when all three types of environmental load (landfill level, global warming potential, and chemical oxygen demand) are considered, the introduction of high‐temperature incineration causes the widening of the Pareto frontier of environmental loads and also causes it to move closer to the origin.     

生物脱氮新工艺研究进展

废水生物脱氮已经成为水污染控制的一个重要研究方向,传统的生物脱氮采用的是硝化－反硝化工艺,但存在很多问题,最近的一些研究表明,生物脱氮过程中出现了一些超出人们转传统认识的新现象,为水处理工作设计处理工艺提供了新的理论思路,现就这一领域的研究进展作一综述。