Biological Treatment Of Effluents Research Articles

Efficiency assessment of aerobic biological effluent treatment plant treating pharmaceutical effluents

The present paper undertakes a study of the physico-chemical properties and toxic heavy metals content in the untreated and treated pharmaceutical effluents in order to evaluate the working efficiency of industrial effluent treatment plants. The treatment efficiency achieved for various parameters was conductivity (79.94%), alkalinity (93.91%), hardness (87.70%), chloride (89.24%), cyanide (79.66%), phosphate (99.19%), total dissolved solids (85.89%), total suspended solids (96.87%), salinity (52.41%), dissolved oxygen (27.32%), biochemical oxygen demand (83.39%) and chemical oxygen demand (72.21%). The removal efficiency achieved for different heavy metals was Cu2+ (79.66%), Ni2+ (69.22%), Cr6+ (80.15%), Pb2+ (72.14%), Fe3+ (92.59%) and Zn2+ (90.61%). The level of biochemical oxygen demand (64 mg L−1) in the treated effluents was above the limit of 30.0 mg L−1, chemical oxygen demand level (208 mg L−1) was close to a limit of 250 mg L−1, while average Pb2+ concentration (0.10 mg L−1) was on the borderline of maximum permissible limit of 0.10 mg L−1 set by Central Pollution Control Board for safe discharge of industrial effluent in inland surface water. The average concentration of cyanide (0.01 mg L−1) in the treated industrial effluent of our study is of great concern to the fisheries of freshwater ecosystem in which the effluents finally get discharged. Based on the results of the present study, it is concluded that the pollution level in the discharged pharmaceutical effluent is of the great concern requiring proper treatment and regular scientific monitoring so as to protect the environmental degradation of water resources and facilitate the propagation of the aquatic life.

Optimization and biokinetic studies on pretreatment of sludge for enhancing biogas production

Excess sludge generation is a major problem in biological effluent treatment processes. Utilization of excess sludge for gas production is an attractive route, which could be enhanced by pretreatment methods. This study involves two sets of experiments. The first set covers mechanical pretreatment of both feed and inoculum. The second set involves alkaline and mechanical treatments of feed and only mechanical treatment of inoculum. Response surface methodology was used for experimental design, analysis and optimization. The optimized mechanical treatment volume of feed was found to be 50%. Diligent mechanical treatment of inoculum resulted in enhanced microbial activity and improved gas production. Reduction in volatile solids, proteins and carbohydrates was observed to a maximum of 63, 84 and 78.5%, respectively. Feed was subjected to alkali treatment in order to reduce mechanical energy input and to improve solubilization. Compared to mechanical treatment alone, enhanced gas production of about 15% was observed at an optimized pH of 11.8 and SRT of 21 days. A biokinetic model was formulated, simulated and validated for the degradation of organics and gas production.

The Reachable set of a Three-Dimensional Nonlinear System Describing Sewage Treatment

The article examines a controlled process of biological treatment of effluents. The model is described by a nonlinear system of three differential equations with one bounded control. We investigate the properties of the solutions of this system: boundedness and continuation on a given interval. The corresponding reachable set is considered. A bound is derived on the number of control switching points required to reach the set boundary.

Calcium carbonate in the paper industry - blessing for coated papermaking and curse for recycling processes

Calcium carbonate provides good optical properties to graphic paper and is relatively inexpensive. Therefore, the use of calcium carbonate for the production of paper has steadily increased. But the high amount of calcium carbonate in paper for recycling and the closure of water circuits leads to a high concentration of calcium ions in the process water of paper mills. The consequence can be undesired precipitation and deposition of calcium carbonate in machines and plant components of the mills. Enhanced knowledge about the precipitation potential of calcium carbonate is needed to avoid or reduce undesired precipitation and deposition. The potential can be described using the Langelier saturation index (LSI). Our investigations showed that a deposition of calcium carbonate only happens if the LSI value is higher than 0.5. An LSI value above 0.5 often exists in process water that is treated in a biological effluent treatment plant. Reasons for such values are the increase in hydrogen carbonate concentration (m-alkalinity) by carbon dioxide production and the increase of the pH value by reduction of fatty acids. With the knowledge about the precipitation potential of calcium carbonate in a process water line, suitable measures could be implemented.

Composition of Organic Compounds and Distribution of Heavy Metals in Sludges During Biological Treatment of Effluents, Including Effluents from Chemical Fiber Production

We have studied the composition of organic compounds in activated sludges of biological treatment facilities and have established the quantitative content of such compounds in the sludges. We have studied the distribution of heavy metals over the constituent phases in the sludges; we have described the mechanism for reaction between the sludge components and the heavy metals, and we have considered the feasibility of extracting them from waste sludges.

Biotreatment of Brewary Effluent Using Pseudomonas Species

During the last two decades the brewing industry has shown increasing awareness for environmental protection and the need of sustainable production processes. Implementation of ISO 14001 certification and more stringent environmental legislation have been important drivers for the brewing industry to invest in biological effluent treatment. The project work was carried with the objective of treating wastewater coming from the brewery effluent was treated with Pseudomonas species over a period of time. The results indicate substantial changes in the effluent. The pH and color of the effluent was found to reduce drastically from higher pH to lower pH i.e. 10.2 to 8.67 and the color from dark black to black. The Pseudomonas on inoculation further reduced the carbohydrate and protein concentration by 56% and 25% respectively. The other components like salts and ammonia were reduced considerably. This particular study further proves the importance of microorganisms in bioremediation of brewery effluent. Based on the socio-economics criteria the anaerobic pretreatment can be combined with aerobic biological post treatment thereby, integrating the advantages of both the processes like reduced energy consumption (net energy production), reduced biological sludge production and limited space requirement. The combination allows for significant savings on operational costs as compared to complete aerobic treatment without comprising the required discharge standards.

Removal of anaerobic soluble microbial products in a biological activated carbon reactor

The soluble microbial products (SMP) in the biological treatment effluent are generally of great amount and are poorly biodegradable. Focusing on the biodegradation of anaerobic SMP, the biological activated carbon (BAC) was introduced into the anaerobic system. The experiments were conducted in two identical lab-scale up-flow anaerobic sludge blanket (UASB) reactors. The high strength organics were degraded in the first UASB reactor (UASB1) and the second UASB (UASB2, i.e., BAC) functioned as a polishing step to remove SMP produced in UASB1. The results showed that 90% of the SMP could be removed before granular activated carbon was saturated. After the saturation, the SMP removal decreased to 60% on the average. Analysis of granular activated carbon adsorption revealed that the main role of SMP removal in BAC reactor was biodegradation. A strain of SMP-degrading bacteria, which was found highly similar to Klebsiella sp., was isolated, enriched and inoculated back to the BAC reactor. When the influent chemical oxygen demand (COD) was 10,000 mg/L and the organic loading rate achieved 10 kg COD/(m3·day), the effluent from the BAC reactor could meet the discharge standard without further treatment. Anaerobic BAC reactor inoculated with the isolated Klebsiella was proved to be an effective, cheap and easy technical treatment approach for the removal of SMP in the treatment of easily-degradable wastewater with COD lower than 10,000 mg/L.

Experimental Research on Recycling Treatment Process of Citrate Wastewater

Researching on the feasibility of citrate wastewater recycling treatment, the combined treatment methods of coagulation and filtration were adopted in the recycling treatment process of citrate wastewater from secondary biological treatment effluents. Meanwhile the ferric salt and water treatment processor were used as the coagulant and filtration equipment respectively. The experiments of coagulant addition, hydraulic retention time, the volume ratio of compounded filtering materials, aeration intensity were taken respectively. The final experimental results demonstrated that at the ferric salt addition of 36 mg/L, hydraulic retention time of 40 min, the volume ratio of biological fibred ball / biological carbon and the ratio of water/gas were 1:2 and 1:6 respectively, 81.3% of COD was removed, from179.2mg/L down to33.6 mg/L and 96.7% of SS was removed, from 152.7mg/L down to below 5mg/L. The effluent of the citrate wastewater recycling treatment process with coagulation + water treatment processor could meet the National standard of Recycling and Miscellaneous usages of Municipal Sewage on COD and SS requirements.

Application of the PDCA Problem-Solving Method in treatment of wastewater from poultry processing (Portuguese)

Dentre as tecnologias que têm sido desenvolvidas para o tratamento de águas residuárias industriais, destacam-se os sistemas por lodos ativados. O presente trabalho teve como objetivo aplicar a metodologia de gestão PDCA na identificação de problemas de um sistema de tratamento biológico de efluente em uma indústria frigorífica de aves, assim como avaliar as soluções prioritárias adotadas ou propostas para a resolução desses problemas. Para alcançar esse objetivo, foram realizadas as seguintes etapas: análise dos inputs e outpus do processo de tratamento de efluente, identificação dos problemas operacionais do sistema mediante o uso de indicadores de desempenho e identificação das causas fundamentais para a geração dos problemas. Para atingir os objetivos, foram levadas a efeito as quatro etapas do ciclo PDCA – planejamento, execução, verificação e ação corretiva. Na etapa do planejamento a identificação do problema foi realizada com base na análise histórica do Índice Volumétrico de Lodos (IVL), cujos resultados apresentaram valores na ordem de 500 mL/g no primeiro semestre de 2010. A análise do fenômeno foi realizada pelo monitoramento de parâmetros físicos, químicos e microbiológicos, efetuado de forma a caracterizar o funcionamento do sistema de tratamento de águas residuárias. O levantamento das causas fundamentais foi realizado por meio das ferramentas de brainstotming, diagrama de Ishikawa e priorização. Os resultados sugerem que após implantação parcial do plano de ação proposto, o problema de sedimentabilidade de lodo, representado pelo IVL, foi minimizado, reduzindo os valores na ordem de 500 mL/g para valores na ordem de 250 mL/g no segundo semestre de 2010. Assim, constata-se que a metodologia PDCA é adequada para solucionar problemas em sistemas de tratamento de efluentes.

Effect of Removal of Hazardous Metals from Effluent of Biological Treatment onto Chitosan using Electrochemical Processing

Effect of Removal of Hazardous Metals from Effluent of Biological Treatment onto Chitosan using Electrochemical Processing

Effluent monitoring at a bleached kraft mill: Directions for best management practices for eliminating effects on fish reproduction

A long-term monitoring study was conducted on effluents from a bleached kraft pulp and paper mill located in Eastern Canada. The study was designed to gain insights into temporal effluent variability with respect to fish reproduction as it related to production upsets, mill restarts and conditions affecting biological treatment performance. Final effluent quality was monitored between February 2007 and May 2009 using biochemical and chemical oxygen demand, total suspended solids, resin and fatty acids, a gas chromatographic profiling index, and the presence of methyl substituted 2-cyclopentenones. Selected effluent samples were evaluated for effects on fish reproduction (egg production) using a shortened version of the adult fathead minnow reproductive test. The events relating to negative effects on fish reproduction were upsets of the pulping liquor recovery system resulting in black liquor losses, operational upsets of the hardwood line resulting in the loss of oxygen delignification filtrates, and conditions that reduced the performance of biological treatment (e.g., mill shutdown and low ambient temperatures). The reductions in egg production observed in fathead minnow were associated with biochemical oxygen demand values > 20 mg/L, GC profiling indices > 1.2 and the presence of methyl-substituted 2-cyclopentenones at concentrations > 100 μg/L. This study demonstrated the importance of both in-plant measures for controlling the loss of organics as well as the optimum operation of biological effluent treatment for eliminating effluent-related effects on fish reproduction (egg production) in the laboratory.

Decolorization of Effluent of Biological Treatment for Cow Stockbreeding Using Activated Carbon/VUV and Fe/H2O2/VUV (Vacuumed Ultraviolet) Treatment

Decolorization of Effluent of Biological Treatment for Cow Stockbreeding Using Activated Carbon/VUV and Fe/H2O2/VUV (Vacuumed Ultraviolet) Treatment

Enhanced decolourization of congo red dye under submerged fermentation (SMF) process by newly isolated Bacillus subtilis SPR42

Studies were carried out on the decolourization of textile azo dye using newly isolated aerobic bacterial culture. Among the 58 strains of aerobic bacteria isolated from soil contaminated with textile industry (Shivalik polymer Ltd. Faridabad) effluent, three showed remarkable ability in decolourizing the widely utilized azo dye (Congo Red). These strains also readily grew in and decolourized the high concentrations of dye (100 mgL -1). The aerobic bacterial isolate SPR42, was able to decolourize the Congo Red dye at a concentration of 100 mgL -1 upto 94% within 24 hrs at static conditions. The temperature and pH for optimum growth and activity of the isolate were reported as 37 oC and 8.5, respectively. The colorless bacterial biomass after decolourization suggested that decolourization was due to biodegradation, rather than inactive surface adsorption. Phenotypic characterization and phylogenetic analysis based on 16S rDNA sequence comparisons indicate that the strain SPR42 identified as Bacillus subtilis. This isolate can be a potential strain for biological treatment of effluents of TPI (Textile Processing Industry).

Effect of backwash and powder activated carbon (PAC) addition on performance of side stream membrane filtration system (SSMFS) on treatment of biological treatment effluent

In this study, a pilot scale Side Stream Membrane Filtration System (SSMFS) was used to demonstrate the need for optimization of backwash conditions and the addition of PAC. Through an investigation of the amount of fouling each cycle that can be restored through backwashing over a short-term, a good operating point for long-term operation was developed. Periodic removal of 1.5% of the PAC slurry mixture (7.5 L out of 500 L) and PAC replacement (15 g/d) was found to have a positive impact on the reduction of membrane fouling.

Biological treatment of the effluent from a bleached kraft pulp mill using basidiomycete and zygomycete fungi

Three white-rot fungi ( Pleurotus sajor caju, Trametes versicolor and Phanerochaete chrysosporium) and one soft-rot fungi ( Rhizopus oryzae) species confirmed their potential for future applications in the biological treatment of effluents derived from the secondary treatment of a bleached kraft pulp mill processing Eucalyptus globulus. Among the four species P. sajor caju and R. oryzae were the most effective in the biodegradation of organic compounds present in the effluent, being responsible for the reduction of relative absorbance (25–46% at 250 nm and 72–74% at 465 nm) and of chemical oxygen demand levels (74 to 81%) after 10 days of incubation. Laccase (Lac), lignin (Lip) and manganese peroxidases (MnP) expression varied among fungal species, where Lac and LiP activities were correlated with the degradation of organic compounds in the effluent treated with P. sajor caju. The first two axes of a principal component analysis explained 88.9% of the total variation among sub-samples treated with the four fungus species, after different incubation periods. All the variables measured contributed positively to the first component except for the MnP enzyme activity which was the only variable contributing negatively to the first component. Absorbances at 465 nm, LiP and Lac enzyme activities were the variables with more weight on the second component. P. sajor caju revealed to be the only species able to perform the biological treatment without promoting an increment in the toxicity of the effluent to the Vibrio fischeri, as it was assessed by the Microtox® assay. The opposite was recorded for the treatments with the other three species of fungus. EC 50–5 min values ranging between 28 and 57% (effluent concentrations) were recorded even after 10 to 13 days of treatment with P. chrysosporium, R. oryzae or with T. versicolor.

Isolation of Arsenite-Oxidizing Bacteria from Arsenic-Enriched Sediments from Camarones River, Northern Chile

In Northern Chile, high arsenic concentrations are found in natural water, both natural and anthropogenic sources, a significant health risk. Nine bacterial strains were isolated from Camarones river sediments, located in Northern Chile, a river showing arsenic concentrations up to 1,100 microg/L. These strains were identified as Pseudomonas and they can oxidize arsenite (As(III)) to the less mobile arsenate (As(V)). The arsenite oxidase genes were identified in eight out of nine isolates. The arsenite oxidizing ability shown by the nine strains isolated from arsenic enriched sediments open the way to their potential application in biological treatment of effluents contaminated with arsenic.

Sequential batch reactor for eucalypt kraft pulp effluent treatment with Trametes versicolor

AbstractBACKGROUND: A sequential batch reactor (SBR) was used for eucalypt kraft pulp effluent treatment with Trametes versicolor. A 23 full factorial design and response surface methodology were applied to optimise the batch fermentation conditions. Effluent concentration, culture medium and inoculum age were the factors selected for this study in order to optimise the reduction of chemical oxygen demand (COD).RESULTS: The presence of Trametes Defined Medium (TDM) in the fermentation was required to obtain a significant COD reduction. Experiments in the batch reactor confirmed, in general, the predicted results of optimisation developed from Erlenmeyer batch assays. The T. versicolor culture remained active during 42 days of study in the SBR, providing approximately 80% of COD reduction.CONCLUSION: Trametes versicolor may be considered as very promising for the biological treatment of effluents from kraft pulp mills in an SBR system instead of the activated sludge mixed cultures traditionally used. Copyright © 2008 Society of Chemical Industry

Eucalyptus kraft pulp bleaching: state-of-the-art and new developments

Chemical demand, yield, water consumption, effluent load and treatability, pulp organic chlorine compounds (OX), brightness stability, refinability, and strength are drivers for choosing bleaching technology. This work critically reviews the state-of-the-art processes for oxygen delignification, first stage, second stage, and final bleaching of eucalyptus kraft pulp in light of those drivers. Emerging technologies, such as the PMo stage and formaldehyde assisted bleaching, are discussed. Implementation of single- or double-stage oxygen delignification is determined by the pulp “true” lignin content. High pulp HexAs content and poor selectivity limits dropping kappa number under 9-10 in single or double O-stage. Mo-catalyzed acid peroxide delignification after O-stage allows further reduction of kappa number to 3-4. Efficient post-oxygen washing is the key for low cost bleaching, with a kilogram of COD/o.d. ton consuming the equivalent to 0.085% active chlorine. A/D-(EP)-D type three-stage sequence suffices for bleaching eucalyptus kraft pulps. The inclusion of a fourth stage is desirable for high brightness/low reversion pulps. Chemical consumption is strongly influenced by brown pulp origin, with variations of 3.2% to 7.7% active Cl2 demand, depending upon the pulp type. The type of elemental chlorine free (ECF) bleaching technology, based on chlorine dioxide, affects chemical consumption only slightly. Hot acid/hot chlorine dioxide bleaching technology saves small amounts of active chlorine for high bleachability pulps, but none for low bleachability ones. Atmospheric extraction (EP) suffices for eucalyptus kraft pulp bleaching. Formaldehyde saves more chlorine dioxide when used in D1 than in D0/DHT stages. A final peroxide stage improves pulp brightness stability. The production of organically bound chlorine decreases by 30% with hot chlorine dioxide bleaching, but this gain disappears after effluent biological treatment.

Treatment by nanofiltration and reverse osmosis of high salinity drilling water for seafood washing and processing Abstract

The Calembo Company (seafood conditioning, Sfax, Tunisia) uses 50 m 3/d of drilling water per ton of fish to condition cuttlefish before freezing. The water used is characterised by its high degree of hardness, high sulphate concentration and salinity (67 g.l −1). Consequently, generated effluents contain a large amount of salts and a high organic load (COD of 10–20 g.l −11). The use of water with high salinity entails difficulties regarding the biological treatment effluents. A membrane bioreactor (MBR) is effective to treat cuttlefish effluent when salinity is lower than 35 g.l −11. In our case, to be in the application range of such MBR process, it is necessary to decrease the salinity of the drilling water. Recently, nanofiltration (NF) membranes have been studied as pre-treatment unit operations both in thermal and membrane seawater desalination processes. In this work, drilling water will be handled using: (1) ultrafiltration and nanofiltration, as a pre-treatment step before desalination process. Three different commercial UF–NF membranes MT03, MT44 and XP117 (cut-offs ranging between 200 to 4000 Dalton) are tested using a tangential flow filtration cell, and (2) high pressure reverse osmosis (the osmotic pressure of drilling water is about 55 bars) to desalt partially the drilling water. Results showed that the MT03 membrane was effective for the removal of natural organic matter and reducing the sulphate concentration in drilling water. Nanofiltration makes possible to have a standardization of the water quality (raw water can vary according to the season and the drilling place). The treatment by RO at high pressure ($70 bars) allows to reduce significantly the salinity of drilling water (permeate salinity about 2 g.l −11). Mixing RO permeate and cuttlefish conditioning effluent together could lead to reduce significantly the salinity of the effluent in view of a biological treatment with a membrane bioreactor (35 g/l or less is required).

Selection and characterization of aerobic bacteria capable of degrading commercial mixtures of low-ethoxylated nonylphenols

Isolation and characterization of new bacterial strains capable of degrading nonylphenol ethoxylates (NPnEO) with a low ethoxylation degree, which are particularly recalcitrant to biodegradation. Seven aerobic bacterial strains were isolated from activated sludges derived from an Italian plant receiving NPnEO-contaminated wastewaters after enrichment with a low-ethoxylated NPnEO mixture. On the basis of 16S rDNA sequence, the strains were positioned into five genera: Ochrobactrum, Castellaniella, Variovorax, Pseudomonas and Psychrobacter. Their degradation capabilities have been evaluated on two commercial mixtures, i.e. Igepal CO-210 and Igepal CO-520, the former rich in low ethoxylated congeners and the latter containing a broader spectrum of NPnEO, and on 4-n-nonylphenol (NP). The strains degraded Igepal CO-210, Igepal CO-520 and 4-n-NP all applied at the initial concentration of 100 mg l(-1), by 35-75%, 35-90% and 15-25%, respectively, after 25 days of incubation. Some of the isolated strains, in particular the Pseudomonas strains BCb12/1 and BCb12/3, showed interesting degradation capabilities towards low ethoxylated NPnEO congeners maintaining high cell vitality. Increased knowledge of bacteria involved in NPnEO degradation and the possibility of using the isolated strains in tailored process for a tertiary biological treatment of effluents of wastewater treatment plants.