Biochemical Oxygen Demand (biochemical + oxygen_demand)

Distribution by Scientific Domains

Selected Abstracts

Influence of temperature on growth of Scenedesmus obliquus in diluted olive mill wastewater as culture medium

Gassan Hodaifa
Abstract Scenedesmus obliquus can help to reduce the environmental impact of industrial olive mill wastewater from olive oil extraction in the three-phase system. This work examines the effect of temperature changes (288,308,K) on algal growth, culture medium, and biochemical composition of S. obliquus. The maximum specific growth rate of 0.024,h,1 occurred at an optimal temperature of 302.7,K. The apparent activation energies of cell growth and cell death were determined as 61.8 and 142.8,kJ/mol, respectively. At the end of culture the percentages of pigments, proteins, and carbohydrates were greater at the two ends of the temperature range studied, as it was also observed for the maximum elimination of biochemical oxygen demand (BOD5). The mono- and polyunsaturated fatty acid content of the biomass was greater at the lowest temperature used (288,K). [source]

Correlation between population dynamics of mosquito larvae and their habitat qualities

Lalit Mohan RANJEETA
Abstract Surveillance of anopheline and culicine larvae was conducted fortnightly to determine population composition and density at seven sites in the area of the Mathura Refinery, Mathura, India during 2005,2006. The correlation between population of the vectors and their habitat quality was established. Temperature (0.978 and 0.85C), pH (0.99 and 0.95), conductivity (0.98 and 0.98 mho) and calcium ion hardness (0.978 and 0.85 p.p.m.) were positively correlated with the populations of both larval species. In contrast, the correlation coefficients between the parameters total hardness, magnesium ion hardness, biochemical oxygen demand and chemical oxygen demand varied with the larval species. The anopheline larval population was dominant over the culicine population in the surveillance area. The distribution of anopheline mosquito larvae during the study period was found to be constant, and the average density of anopheline and culicine larvae was 84.70 and 15.30%, respectively, across all seven sites. Thus, the study demonstrated spatial and temporal population differences of mosquito larvae with respect to environmental factors, including water quality. [source]

Efficiency of permeable pavement systems for the removal of urban runoff pollutants under varying environmental conditions

Kiran Tota-Maharaj
Abstract Urban surface water runoff typically contains a high but variable number of pathogens, nutrients, and sediments that require removal before reuse. Permeable pavements can improve the water quality through interception, filtration, sedimentation, nutrient transformation, and microbial removal. There is currently insufficient scientific information available on the treatment efficiencies of permeable pavements combined with earth energy systems with regards to the removal of storm water pollutants such as nutrients, sediments, and microbial pollutants. This study evaluates the efficiency of 12 tanked combined systems during a medium-term study. The research assessed weekly the removal of the microbial indicators total coliforms, Escherichia coli, and fecal Streptococci, as well as the key nutrients ammonia-nitrogen, nitrate-nitrogen, and ortho-phosphate-phosphorus, and physical variables such as suspended solids and turbidity. Total coliforms, E. coli, and fecal Streptococci were removed by 98,99%. The ammonia-nitrogen and ortho-phosphate-phosphorus removal efficiencies were 84.6% and 77.5%, respectively. An analysis of variance indicated that the presence or absence of a geotextile did result in a very highly statistically significant difference (P < 0.001) with respect to the removal of both ammonia-nitrogen and ortho-phosphate-phosphorus. Suspended solids, turbidity, and biochemical oxygen demand were reduced by 91%, 82%, and 88%, respectively. These results indicate the potential of the proposed novel system in urban runoff pollutant removal and subsequent reuse of the treated water. 2010 American Institute of Chemical Engineers Environ Prog, 2010 [source]

Potential for 4- n -nonylphenol biodegradation in stream sediments

Paul M. Bradley
Abstract The potential for in situ biodegradation of 4-nonylphenol (4-NP) was investigated in three hydrologically distinct streams impacted by wastewater treatment plants (WWTPs) in the United States. Microcosms were prepared with sediments from each site and amended with [U-ring- 14C]4- n -nonylphenol (4- n -NP) as a model test substrate. Microcosms prepared with sediment collected upstream of the WWTP outfalls and incubated under oxic conditions showed rapid and complete mineralization of [U-ring- 14C]4-n-NP to 14CO2 in all three systems. In contrast, no mineralization of [U-ring- 14C]4- n -NP was observed in these sediments under anoxic (methanogenic) conditions. The initial linear rate of [U-ring- 14C]4- n -NP mineralization in sediments from upstream and downstream of the respective WWTP outfalls was inversely correlated with the biochemical oxygen demand (BOD) of the streambed sediments. These results suggest that the net supply of dissolved oxygen to streambed sediments is a key determinant of the rate and extent of 4-NP biodegradation in stream systems. In the stream systems considered by the present study, dissolved oxygen concentrations in the overlying water column (8,10 mg/L) and in the bed sediment pore water (1,3 mg/L at a depth of 10 cm below the sediment,water interface) were consistent with active in situ 4-NP biodegradation. These results suggest WWTP procedures that maximize the delivery of dissolved oxygen while minimizing the release of BOD to stream receptors favor efficient biodegradation of 4-NP contaminants in wastewater-impacted stream environments. [source]

Fate of estrogens and xenoestrogens in four sewage treatment plants with different technologies,

Guang-Guo Ying
Abstract The fate and removal of the estrogens 17,-estradiol (E2), estrone (E1), and 17,-ethynylestradiol (EE2) and of the xenoestrogens bisphenol A (BPA), 4- tert -octylphenol (4- t -OP), 4-nonylphenol (4-NP), and nonylphenol mono- and diethoxylate (NPEO1 and NPEO2, respectively) were investigated in four South Australian sewage treatment plants (STPs; plants A,D) with different treatment technologies. The concentrations in the effluent from the two-year survey were similar to those reported in other studies. In the effluent, 4-NP, NPEO1, and NPEO2 had total concentrations up to 8 ,g/L, which were much higher than those of BPA and 4-t-OP. Estrone had the highest concentrations among the three estrogens, ranging between 13.3 and 39.3 ng/L, whereas the concentrations for E2 and EE2 varied between 1.0 and 4.2 ng/L and between 0.1 and 1.3 ng/L, respectively. The removal rates for the estrogens and xenoestrogens were variable but consistent with the plant performance parameters (biochemical oxygen demand, suspended solids, and ammonia). Considering all the estrogenic compounds analyzed in the present study, plant D, with a series of anaerobic and aerobic lagoons, was the least efficient of the four STPs in the removal of these compounds. The removal rates for 4-NP, NPEO1, and NPEO2 within the plants were 92% for plant A, with conventional activated sludge treatment; 80% for plant B, with two oxidation ditches; 70% for plant C, with three bioreactors; and 64% for plant D, with 10 lagoons in series. Comparatively, the removal of estrogens was lower, with rates ranging between 47 and 68% for E2 at the four plants. Both E1 and EE2 were more persistent during treatment, especially in plants C and D. [source]

Toxicity and chemistry of aspen wood leachate to aquatic life: Field study

Barry R. Taylor
Abstract A dark, toxic leachate has been observed around woodpiles of trembling aspen (Populus tremuloides Michx.) cut in winter for pulp or structural lumber. We measured production of leachate from 18 m3 of harvestable aspen logs stacked in an open field near Dawson Creek, British Columbia, Canada. The logpile began producing leachate during the first winter thaw and continued to do so for the duration of the two-year study (mean, 250 L/collection). Aspen leachate was characterized by dark color, acidic pH (5.0-6.5), elevated conductivity (200-500 ,S/cm), high to very high biochemical oxygen demand (500-5,000 mg/L) and total organic carbon concentrations (500-2,000 mg/L), variable levels of phenolic compounds (2-27 mg/L), and low dissolved oxygen tensions (<2 mg/L). In tests with rainbow trout (Oncorhynchus mykiss), Daphnia magna, and luminescent bacteria, the leachate varied from weakly toxic (median lethal concentration, >10%) to very toxic (median lethal concentration, <1%). The volume of leachate generated by the logpile was correlated with total precipitation (rain or snow) since the last collection. Loads of chemical constituents or toxicity (lethal concentration volume) in the leachate did not decline over the duration of the study. Less than 10% of the total mass of leachable material in the aspen logs was removed during two years of exposure. [source]

Response of bacterioplankton community structures to hydrological conditions and anthropogenic pollution in contrasting subtropical environments

Rui Zhang
Abstract Bacterioplankton community structures under contrasting subtropical marine environments (Hong Kong waters) were analyzed using 16S rRNA gene denaturing gradient gel electrophoresis (DGGE) and subsequent sequencing of predominant bands for samples collected bimonthly from 2004 to 2006 at five stations. Generally, bacterial abundance was significantly higher in the summer than in the winter. The general seasonal variations of the bacterial community structure, as indicated by cluster analysis of the DGGE pattern, were best correlated with temperature at most stations, except for the station close to a sewage discharge outfall, which was best explained by pollution-indicating parameters (e.g. biochemical oxygen demand). Anthropogenic pollutions appear to have affected the presence and the intensity of DGGE bands at the stations receiving discharge of primarily treated sewage. The relative abundance of major bacterial species, calculated by the relative intensity of DGGE bands after PCR amplification, also indicated the effects of hydrological or seasonal variations and sewage discharges. For the first time, a systematic molecular fingerprinting analysis of the bacterioplankton community composition was carried out along the environmental and pollution gradient in a subtropical marine environment, and it suggests that hydrological conditions and anthropogenic pollutions altered the total bacterial community as well as the dominant bacterial groups. [source]

Trends in water quality and discharge confound long-term warming effects on river macroinvertebrates

Summary 1.,Climate-change effects on rivers and streams might interact with other pressures, such as pollution, but long-term investigations are scarce. We assessed trends among macroinvertebrates in 50 southern English streams in relation to temperature, discharge and water quality over 18 years (1989,2007). 2.,Long-term records, coupled with estimates from inter-site calibrations of 3,4 years, showed that mean stream temperatures in the study area had increased by 2.1,2.9 C in winter and 1.1,1.5 C in summer over the 26 year period from 1980 to 2006, with trends in winter strongest. 3.,While invertebrate assemblages in surface-fed streams were constant, those in chalk-streams changed significantly during 1989,2007. Invertebrate trends correlated significantly with temperature, but effects were spurious because (i) assemblages gained taxa typical of faster flow or well-oxygenated conditions, contrary to expectations from warming; (ii) more invertebrate families increased in abundance than declined and (iii) concomitant changes in water quality (e.g. declining orthophosphate, ammonia and biochemical oxygen demand), or at some sites changes in discharge, explained more variation in invertebrate abundance and composition than did temperature. 4.,These patterns were reconfirmed in both group- and site-specific analyses. 5.,We conclude that recent winter-biased warming in southern English chalk-streams has been insufficient to affect invertebrates negatively over a period of improving water quality. This implies that positive management can minimize some climate-change impacts on stream ecosystems. Chalk-stream invertebrates are sensitive, nevertheless, to variations in discharge, and detectable changes could occur if climate change alters flow pattern. 6.,Because climatic trends now characterize many inter-annual time-series, we caution other investigators to examine whether putative effects on ecological systems are real or linked spuriously to other causes of change. [source]

Annual cycle and inter-annual variability of gross primary production and ecosystem respiration in a floodprone river during a 15-year period

Summary 1. Temporal variation in ecosystem metabolism over a 15-year period (1986,2000) was evaluated in a seventh order channelised gravel bed river (mean annual discharge 48.7 m3 s,1) of the Swiss Plateau. The river is subject to frequent disturbance by bed-moving spates. Daily integrals of gross primary production (GPP) and ecosystem respiration (ER) were calculated based on single-station diel oxygen curves. 2. Seasonal decomposition of the time series of monthly metabolism rates showed that approximately 50% of the variation of GPP and ER can be attributed to season. Annual GPP averaged 5.0 0.6 g O2 m,2 day,1 and showed no long-term trend. 3. Ecosystem respiration, averaging 6.2 1.4 g O2 m,2 day,1, declined from 8.8 to 4.1 g O2 m,2 day,1 during the 15-year period. This significant trend paralleled a decline in nitrate and soluble reactive phosphorus concentrations, and the biochemical oxygen demand discharged by sewage treatment facilities upstream of the study reach. The ratio of GPP to ER (P/R) increased from 0.53 to about 1 as consequence of ER reduction. 4. Bed moving spates reduced GPP by 49% and ER by 19%. Postspate recovery of GPP was rapid between spring and autumn and slow during winter. Recovery of ER lacked any seasonal pattern. Annual patterns of daily GPP and to a minor extent of daily ER can be described as a sequence of recovery periods frequently truncated by spates. 5. The study showed that disturbance by frequent bed-moving spates resulted in major stochastic variation in GPP and ER but annual patterns were still characterised by a distinct seasonal cycle. It also became evident that stream metabolism is a suitable method to assess effects of gradual changes in water quality. [source]

A study of the effect of isothiazolones on the performance and characteristics of a laboratory-scale rotating biological contactor

L. Laopaiboon
Aims: To study the effect of the isothiazolone biocide (Kathon WT) on the performance of laboratory-scale rotating biological contactors (RBCs) and their component biofilms. Methods and Results: Biofilms were established on the RBCs and then exposed to 07,15 p.p.m. isothiazolones. Young, 1-week-old, biofilms were found to attain treatment efficiency equal to that of mature, 2-month-old, biofilms. Isothiazolone concentrations at 3 p.p.m. and above caused a progressive decline in treatment efficiency and 15 p.p.m. isothiazolones inhibited all microbial activity and resulted in the death of the biofilms. Bio-oxidation and the biodegradation of isothiazolones within the biofilms ontinued unhindered at concentrations which caused the total inhibition of planktonic bacteria. Conclusions: There was at least a 10-fold difference in susceptibility of planktonic and biofilm bacteria to isothiazolones. The chemical oxygen demand (COD) test was shown to be a reliable tool for investigating the efficiency of wastewater treatment units when the influent contains isothiazolones, while the biochemical oxygen demand (BOD) was unreliable due to the inhibition of bio-oxidation by the biocide. Significance and Impact of the Study: The results show that RBCs can be used to treat effluents containing isothiazolones at concentrations up to 15 p.p.m. [source]

Biodegradation of poly(butylene adipate- co -butylene terephthalate)/layered-silicate nanocomposites

Yoshihiro Someya
Abstract The biodegradability of poly(butylene adipate- co -butylene terephthalate) (PBAT) and PBAT/starch composites with layered silicates prepared by melt intercalation was evaluated with aerobic biodegradability tests in soil and in an aqueous medium containing activated sludge. Nonmodified montmorillonite (MMT) and octadecylamine-modified montmorillonite (ODA-M), known to give a microcomposite and an intercalated nanocomposite for PBAT, respectively, were used as layered silicates. After they were buried in the soil for 8 months, the PBAT/MMT microcomposite exhibited a higher weight loss than the control PBAT, whereas the PBAT/ODA-M nanocomposite showed a lower weight loss instead. Also, the biodegradability test in the aqueous medium, by determining the biochemical oxygen demand, showed that the addition of MMT and/or starch to PBAT promoted biodegradation, whereas the addition of ODA-M did not. 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007 [source]

Cell growth and Trametes versicolor laccase production in transformed Pichia pastoris cultured by solid-state or submerged fermentations

Marcos Lpez
Abstract BACKGROUND: Growth kinetics of Pichia pastoris and heterologous expression of Trametes versicolor laccase were compared. This is the first study of its kind between solid-state yeast cultures done on polyurethane foam (PUF) and submerged liquid fermentations (SmF). RESULTS: The maximum values of biomass were similar for SSF (solid-state fermentation) and SmF experiments when the BOD (biochemical oxygen demand) was lower than 100 g L,1. For higher BOD levels, the maximum values of biomass were 55 g L,1 (SSF) and 35 g L,1 (SmF). Micrographs of PUF preparations showed yeast growing within liquid lamellae, thinner than 100 m, forming large horizontal aggregates. Yeast aggregates were much smaller in SmF than in SSF experiments; however, laccase expression was lower in PUF than in SmF, unless the methanol concentration was increased to 63 g L,1, which was inhibitory only to the SmF system. CONCLUSION: The results show that oxygen mass transfer is more efficient in SSF, which is related to the higher area/volume ratio compared with SmF. Induction differences may also be due to hindered diffusion of methanol within large yeast aggregates. Copyright 2009 Society of Chemical Industry [source]

Ozonation of complex industrial park wastewater: effects on the change of wastewater characteristics

Jen-Mao Fanchiang
Abstract BACKGROUND: Ozonation of complex industrial park wastewater was carried out in a semi-batch reactor. The variation of wastewater characteristics was evaluated based on the analysis of 5-day biochemical oxygen demand (BOD5) concentration, BOD5/chemical oxygen demand (COD) ratio, COD fractionation, and dissolved organic carbon (DOC) molecular size distribution before and after ozonation. RESULTS: The experimental results indicated that low efficiency of COD removal with increasing tendency of BOD5 concentration generally appeared after ozonation. Also, the BOD5/COD ratio increased from an initial of 0.27 to a maximum of 0.38. The COD fractionation tests revealed that most of the inert soluble COD was transformed to biodegradable soluble COD at 30 min of reaction time. Additionally, the DOC molecular size distribution tests showed that the fraction larger than 500 kDa was significantly decreased and the fraction smaller than 2 kDa was increased when the reaction time was prolonged to 240 min. CONCLUSION: This study verified that partial oxidation of the complex industrial park wastewater by ozonation could enhance wastewater biodegradability. The biodegradability enhancement was primarily because the inert soluble COD fraction was converted to the biodegradable soluble COD and the high molecular weight fraction of DOC was shifted toward the low molecular weight fraction. Copyright 2009 Society of Chemical Industry [source]

Performance assessment of a UASB,anoxic,oxic system for the treatment of tomato-processing wastes

Alpesh Gohil
Abstract An upflow anaerobic sludge blanket (UASB),anoxic,oxic system was used to achieve biochemical oxygen demand, NH4 and total suspended solids (TSS) criteria of 15, 1 and 15 mg dm,3 at 1.17 days of system hydraulic retention time during treatment of tomato-processing waste. The incorporation of an anoxic tank was found to affect the improvement in sludge-settling characteristics, as reflected by about 25,33% reduction in the sludge volume index, along with final effluent TSS and soluble biochemical oxygen demand concentrations of 13 and 9 mg dm,3, respectively, which met the discharge criteria. Despite incomplete denitrification, sludge settleability was very good (sludge volume index < 60 cm3 g,1) owing to reduction in volatile suspended solids/TSS ratio from 0.75 to 0.6 as a result of higher alkalinity in the UASB effluent. Also in this study, phosphorus release was observed in the anoxic tank, predominantly due to abundance of acetic acid in the UASB effluent. A phosphate release of 5.4 mg P dm,3 was observed in the anoxic tank with subsequent P uptake in the following aerobic stage. Copyright 2006 Society of Chemical Industry [source]

Studies on internal and external water treatment at a paper and cardboard factory

Mamdouh M Nassar
Abstract The treatment of effluent from a paper/board factory that produced 280 tons of cardboard and consumed 1200 m3 of water per day was carried out. Wastewater analysis showed that the mill effluent contained 3000 mg dm,3 suspended solids, 1400 mg dm,3 COD (chemical oxygen demand) and 500 mg dm,3 BOD (biochemical oxygen demand). An internal treatment cycle is suggested that involves recirculation of paper-machine wastewater (white-water) and may be accomplished by installing a flotation saveall (fiber recovery) unit. This arrangement reduced fresh water use by about 90%, reduced fiber loss by 80,90%, and increased board production by 13%. An external treatment process for the effluent was assessed by conducting laboratory coagulation tests (alum, ferric chloride, ferrous sulfate, and polyelectrolyte) on the whole mill effluent. Oxidation of the mill effluent using calcium hypochlorite before discharging the effluent to a lagoon offers the benefits of killing the harmful bacteria and reducing the pollution load. Copyright 2003 Society of Chemical Industry [source]

Biodegradable polymers based on renewable resources.


Abstract Novel polycarbonates, with pendant functional groups, based on 1,4:3,6-dianhydrohexitols and L -tartaric acid derivatives were synthesized. Solution polycondensations of 1,4:3,6-dianhydro-bis- O -(p -nitrophenoxycarbonyl)hexitols and 2,3-di- O -methyl- L -threitol or 2,3- O -isopropylidene- L -threitol afforded polycarbonates having pendant methoxy or isopropylidene groups, respectively, with number average molecular weight (Mn) values up to 3.61 104. Subsequent acid-catalyzed deprotection of isopropylidene groups gave well-defined polycarbonates having pendant hydroxyl groups regularly distributed along the polymer chain. Differential scanning calorimetry (DSC) demonstrated that all the polycarbonates were amorphous with glass transition temperatures ranging from 57 to 98 C. Degradability of the polycarbonates was assessed by hydrolysis test in phosphate buffer solution at 37 C and by biochemical oxygen demand (BOD) measurements in an activated sludge at 25 C. In both tests, the polycarbonates with pendant hydroxyl groups were degraded much faster than the polycarbonates with pendant methoxy and isopropylidene groups. It is noteworthy that degradation of the polycarbonates with pendant hydroxyl groups was remarkably fast. They were completely degraded within only 150 min in a phosphate buffer solution and their BOD-biodegradability reached nearly 70% in an activated sludge after 28 days. The degradation behavior of the polycarbonates is discussed in terms of their chemical and physical properties. 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 3909,3919, 2005 [source]


Stephen R. Pennington
ABSTRACT: Municipalities will be implementing structural best management practices at increasing rates in their effort to comply with Phase II of the National Pollutant Discharge Elimination System (NPDES). However, there is evidence that structural best management practices (BMPs) by themselves may be insufficient to attain desired water quality standards. This paper reports on an analysis of the median removal efficiencies of structural BMPs and compares them to removal efficiencies estimated as being necessary to attain water quality standards in the Rouge River in Detroit, Michigan. Eight water quality parameters are reviewed using data collected from 1994 to 1999 in the Rouge River. Currently, five of the eight parameters in the Rouge River including bacteria, biochemical oxygen demand, and total suspended solids (TSS) exceed the required water quality standards. The reported analysis of structural BMP efficiencies reveals that structural BMPs appear capable of reducing only some of the pollutants of concern to acceptable levels. [source]


Carl E. Zipper
ABSTRACT: Nine surface water-quality variables were analyzed for trend at 180 Virginia locations over the 1978 to 1995 period. Median values and seasonal Kendall's tau, a trend indicator statistic, were generated for dissolved oxygen saturation (DO), biochemical oxygen demand (BOD), pH (PH), total residue (TR), nonfilterable residue (NFR), nitrate-nitrite nitrogen (NN), total Kjeldahl nitrogen (TKN), total phosphorus (TP), and fecal coliform (FC) at each location. Each location was assigned to one of four physiographic regions, and mean state and regional medians and taus were calculated. Widespread BOD and NFR improvements were detected and FC improvements occurred in the state's western regions. TR and TKN exhibited predominantly increasing trends at locations throughout the state. BOD, TKN, NFR, and TR medians were higher at coastal locations than in other regions. NN, TKN, and TR exhibited predominantly increasing trends in regions with high median concentrations, while declining trends predominated in regions with relatively high BOD, FC, and NFR medians. Appalachian locations exhibited the greatest regional water-quality improvements for BOD, FC, NFR, and TKN. Factors responsible for regional differences appear to include geology, land use, and landscape features; these factors vary regionally. [source]


Erik R. Lee
ABSTRACT: A dynamic, compartmental, simulation model (WETLAND) was developed for the design and evaluation of constructed wetlands to optimize nonpoint source (NPS) pollution control. The model simulates the hydrologic, nitrogen, carbon, dissolved oxygen (DO), bacteria, vegetative, phosphorous, and sediment cycles of a wetland system. Written in Fortran 77, the WETLAND models both free-water surface (FWS) and subsurface flow (SSF) wetlands, and is designed in a modular manner that gives the user the flexibility to decide which cycles and processes to model. WETLAND differs from many existing wetland models in that the interactions between the different nutrient cycles are modeled, minimizing the number of assumptions concerning wetland processes. It also directly links microbial growth and death to the consumption and transformations of nutrients in the wetland system. The WETLAND model is intended to be utilized with an existing NPS hydro-logic simulation model, such as ANSWERS or BASINS, but also may be used in situations where measured input data to the wetland are available. The model was calibrated and validated using limited data from a FWS wetland located at Benton, Kentucky. The WETLAND predictions were not statistically different from measured values for of five-day biochemical oxygen demand (BOD5), suspended sediment, nitrogen, and phosphorous. Effluent DO predictions were not always consistent with measured concentrations. A sensitivity analysis indicated the most significant input parameters to the model were those that directly affected bacterial growth and DO uptake and movement. The model was used to design a hypothetical constructed wetland in a subwatershed of the Nomini Creek watershed, located in Virginia. Two-year simulations were completed for five separate wetland designs. Predicted percent reductions in BOD5 (4 to 45 percent), total suspended solids (85 to 100 percent), total nitrogen (42 to 56 percent), and total phosphorous (38 to 57 percent) were similar to levels reported by previous research. [source]

Biological treatment of textile dye Acid violet-17 by bacterial consortium in an up-flow immobilized cell bioreactor

D.K. Sharma
Abstract Aims:, To develop a cost effective and efficient biological treatment process for small scale textile processing industries (TPI) releasing untreated effluents containing intense coloured Acid violet-17 (AV-17), a triphenyl methane (TPM) group textile dye. Methods and Results:, The samples collected from effluent disposal sites of TPI were used for selective enrichment of microbial populations capable of degrading/decolourizing AV-17. A consortium of five bacterial isolates was used to develop an up-flow immobilized cell bioreactor for treatment of feed containing AV-17. The bioreactor, operating at a flow rate of 6 ml h,1, resulted in 91% decolourization of 30 mg AV-17/l with 943 and 957% removal of biochemical oxygen demand and chemical oxygen demand of the feed. Comparison of the input and output of the bioreactor by UV-visible, thin layer chromatography and 1H-nuclear magnetic resonance spectroscopy indicates conversion of the parent dye into unrelated metabolic intermediates. Significance:, These results will form a basis for developing ,on-site' treatment system for TPI effluents to achieve decolourization and degradation of residual dyes. [source]

Synthesis and photocuring of cinnamoyl trehalose esters

Naozumi Teramoto
Abstract A trehalose cinnamoyl ester (TC) was synthesized from trehalose and cinnamoyl chloride in dimethylformamide (DMF) in the presence of triethylamine and 4-(N,N -dimethylamino)pyridine. The product was characterized by 1H NMR spectroscopy to reveal that the reaction proceeded. Two different types of TCs were synthesized by changing the feed ratio of cinnamoyl chloride to trehalose. When the feed ratio of cinnamoyl chloride to trehalose was 8 (TC8), the degree of substitution (DS) was 8.0, while it was 4.2 when the feed ratio was 4 (TC4). Photocuring was confirmed by observing changes in UV absorption spectrum and FT Infrared (IR) spectrum. After 5,min of UV irradiation, solubility in chloroform significantly decreased. A transparent thin coating film of TC was easily prepared by casting from a chloroform solution on a Petri dish and UV irradiation was carried out over a simple photomask. After TC within the non-irradiated region was removed by flash soaking with chloroform, the shape of the photomask appeared. A scanning electron microscope (SEM) measurement revealed that the surface of the photocured coating film was smooth and that the edge of the photocured TC had a characteristic feature. Biodegradation of the photocured TC and non-irradiated TC was examined by the biochemical oxygen demand (BOD) method using activated sludge. Copyright 2007 John Wiley & Sons, Ltd. [source]

Screening co-digestion of food waste water with manure for biogas production

Yan Liu
Abstract Anaerobic digestion, an environmental protection technology for treating organic compounds in waste water, produces biogas, resulting in a renewable energy source. A protocol including waste analysis, waste blending, energy potential and energy balance calculations was developed to determine the energy production from blending food and animal wastes. Fruit and vegetable waste water produced from crop commodity processing was characterized in terms of quantity and 5-day biochemical oxygen demand (BOD). Often these wastes have high levels of degradable carbon but lack buffering capacity and adequate nitrogen and other nutrients to meet the minimal C/N ratio needed for optimal digestion. Blending food-processing waste water with high nutrient manure can enhance the biogas production by optimizing nutrient levels and providing buffering capacity. The protocol shows the procedure to determine the optimal blend and theoretical biogas production from the anaerobic digestion of that blend. An energy balance technique that determines the lowest COD concentration required to close the energy balance in the digester during different seasons is illustrated. A case study was conducted to determine the potential energy production from anaerobically digesting blended waste water from the top 14 fruit and vegetable commodities in Michigan. The resulting biogas production supports a substantial amount of the energy consumption needed for the treatment process. This case study in Michigan can be extended to national level since the calculations were based on the mean value of their typical range. 2008 Society of Chemical Industry and John Wiley & Sons, Ltd [source]