Nitrate removal from the effluent of a fertilizer industry using a bioreactor packed with immobilized cells of <Emphasis Type="Italic">Pseudomonas stutzeri</Emphasis>and<Emphasis Type="Italic">Comamonas testosteroni</Emphasis>

A bioreactor for the removal of nitrate nitrogen (NO₃-N) from industrial effluent is described which is comprised of a glass column (60 cm × 6 cm) packed with alginate beads containing denitrifying organisms Pseudomonas stutzeri and Comamonas testosteroni. The effluent containing high concentrations of nitrate (600–950 mg l^–1) from the fertilizer industry and fusel oil (methanol as a major component) as organic carbon were used in the process. The reactor is operated in the continuous mode by injecting the pretreated nitrate-containing effluent at the top of the column. The Hydraulic retention time (HRT) was adjusted by changing the flow rates. When nitrate-containing wastewater was treated with immobilized cells, the nitrate removal rate reached a maximum 1.66 ± 0.07 Kg NO₃-N m^–3d^–1 at an influent NO₃-N concentration of 850 mg NO_3M-N l^–1within 12 h. The denitrification activity of the immobilized cells was compared with that of the free cells.     

Production of vitamin B12 in an upflow anaerobic filter continuous reactor using Acetobacterium sp.

The accumulation of biofilm by Acetobacterium sp. during continuous culture in an upflow anaerobic filter (UAF) growing on methanol-formate was the result of space velocity and inlet concentrations of substrate and Co⁺². To achieve good development of biofilm, a space velocity of 0.38 h^–1, inlet substrate concentrations of 125 mM of both methanol and formate, and Co⁺² at 0.16 mM were required. Cell productivities in the effluent of the UAF-reactor were about 6-fold higher than in chemostat cultures (0.20 g l^–1 h^–1 for UAF and 0.035 g l^–1 h^–1 for chemostat) (previous studies), and the maximum vitamin B₁₂ specific concentration was 5.1 mg g cell^–1.     

Rapid granulation and sludge retention for tetrachloroethylene removal in an upflow anaerobic sludge blanket reactor

A laboratory scale upflow anaerobic sludge blanket (UASB) reactor was operated at 35 °C for over 200 days to investigate the granulation mechanism during tetrachloroethylene (TCE) biodegradation. Anaerobic, unacclimated sludge and glucose were used as seed and primary substrate, respectively. TCE-degrading granules developed after 1.5 months of start-up. They grew at an accelerated pace for 7 months. The TCE-degrading granules had a maximum diameter of 2.5 mm and specific methanogenic activity of 1.32 g chemical oxygen demand (COD) g^–1 total suspended solid (TSS) day^–1. 94% COD and 90% TCE removal efficiencies were achieved when the reactor was operating at loading rates as high as 160 mg TCE l^–1 day^–1 and 14 g COD l^–1 day^–1, after 230 days of continuous operation.     

Nitrifying activity monitoring and kinetic parameters determination in a biofilm airlift reactor by respirometry

The applicability of batch respirometry, as a simple technique for monitoring off-line nitrifying activity and kinetic parameters, was evaluated using two sets of ammonia and nitrite concentrations. The O₂ uptake rate (OUR) profiles obtained from the assays were adjusted to a substrate inhibition model. The maximum specific ammonia-oxidizing biomass activity (r_Smax) was 0.079 g N-NH₄ ⁺ g VSS^–1 d^–1 with a half saturation coefficient (K_S) of 11 mg N-NH₄ ⁺ l^–1 and an inhibition coefficient (K_i) of 3300 mg N-NH₄ ⁺ l^–1. Besides, the maximum specific value of nitrite-oxidizing activity was 0.082 g N-NO₂ ^– g VSS^–1 d^–1 with a K_S of 4.1 mg N-NO₂ ^– l^–1 and K_i of 1400 mg N-NO₂ ^– l^–1.     

Phototrophic bacterial production of oleic acid in an illuminated upflow anaerobic sludge blanket reactor

Phototrophic bacterial cells in the effluent from a lighted upflow anaerobic sludge blanket reactor supplied with a medium containing 142 mg S (as SO₄ ^2–) l^–1 accumulated a 6.8% w/w oleic acid content in cells and 19 mg cell-bound oleic acid l^–1 in the effluent. Pure cultures of Rhodopseudomonas palustris and Blastochloris sulfoviridis isolated from the effluent also accumulated 5.1 and 6.4% w/w oleic acid contents in cells, respectively. The oleic acid content in the cells recovered from the LUASB reactor effluent was related to the phototrophic bacterial population in the LUASB reactor. The inverse relationship was observed in the LUASB reactor between phototrophic bacterial growth and sulfate concentration in the influent.     

Evaluation of the environmental conditions for the continuous production of lignin peroxidase by Phanerochaete Chrysosporium in fixed-bed bioreactors

A new system to produce lignin peroxidase (LiP) continuously by Phanerochaete chrysosporium is described. A fixed-bed bioreactor with a pulsing device was used as the optimal bioreactor configuration. Addition of veratryl alcohol (1 mM), tryptophan (1 mM), no Mn²⁺ addition, low glucose addition rate (60–70 mg l^–1 h) and an atmosphere of O₂ gave maximum LiP activities of 700 U l^–1, which are higher than those previously reported.     

Degradation of dye-containing textile effluent by the agaric white-rot fungus Clitocybula dusenii

Raw mixed-dye wastewater from a textile dye-producing plant was partly decolorized by the agaric white-rot fungus, Clitocybula dusenii. The fungus had higher Mn peroxidase (MnP) and laccase activities when grown with dye effluent than in control cultures. The activity of MnP increased commensurately with the proportion of the raw dye wastewater in the medium (control: 20 U l^–1; 10% v/v effluent: 67 U l^–1; 25% v/v effluent: 130 U l^–1; and 33% v/v effluent: 180 U l^–1). Maximal decolorization rates were achieved over 20 d at 28 °C using four-fold diluted dye-containing effluent on a 5 d pre-grown mycelium.     

On-line measurement of dissolved and gaseous hydrogen sulphide in anaerobic biogas reactors

The paper presented demonstrates the calibration of a silicone membrane probe for measurement of hydrogen sulphide in liquid and gas phase. The probe is connected to a quadrupole mass spectrometer as detector. The calibration of the probe results in linear calibration functions for different liquids and the gas phase. An example of the application of the measuring device for on-line measurement is reported for an experiment where sulphide is precipitated as iron sulphide by the addition of ferrous chloride. As a consequence of the addition of ferrous chloride, the concentration of H₂S in the biogas rapidly decreases from 4.2% to 1.0% (by volume). The inhibition of the anaerobic treatment process is calculated on the basis of the reduction of dissolved total organic carbon before and during the experiment. The reduction of dissolved total organic carbon before the experiment starts is constant at 60%, rising to a maximum of 70% during the addition of FeCl₂. The difference in the conversion rate corresponds to an inhibition of about 14%. The gas production increases from 7.51 l^–1 day^–1 to 8.51 l^–1 day^–1. This inhibition observed before the addition of FeCl₂ is caused by 65 mg/l undissociated hydrogen sulphide in the liquid phase as calculated from the data obtained after precipitation of sulphide as zinc sulphide. The data show clearly that the conversion of acetic acid to methane is inhibited by dissolved H₂S. The concentration of acetic acid drops sharply from about 25 mM to 15 mM after the FeCl₂ dosage has been started. The concentration of propionic acid decreases slightly from 12 mM to 9 mM. Most of the iron introduced during the experiment is immediately precipitated. The maximum concentration of dissolved iron measured in the effluent is 93 mg/l.     

Efficient GA3-assisted plant regeneration from cell suspensions of three grape genotypes via somatic embryogenesis

Petioles from in vitro grown plants of interspecific grapevine hybrids cvs `Bianca', `Podarok Magaracha' and `Intervitis Magaracha' were cultured on solid NN medium supplemented with 2,4-D and BA at various concentrations. The callus developed was cultured in liquid NN medium supplemented with 0.5 mg l<sup>–1</sup> BA to induce formation of somatic embryos. Somatic embryos of globular and heart-stage developed in suspensions of `Podarok Magaracha' and `Intervitis Magaracha'. In contrast, `Bianca' did not undergo embryogenesis beyond globular stage. This made it necessary to perform subculture of the suspensions to HTE liquid medium supplemented with 0.2 mg l^–1 BA for the development of globular embryos into heart stage. Heart-stage embryos developed into torpedo-stage after subculturing suspensions of all three cultivars to liquid HTE medium supplemented with 0.1 mg l^–1 IAA and 30 mg l^–1 sodium hummate. Torpedo-stage embryo suspensions were subcultured in liquid HTE medium supplemented with 0.5 mg l^–1 BA, 0.5 mg l^–1 GA₃ and 0.5 mg l^–1 GA₃ + 0.2 mg l^–1 BA. After 12 days of incubation, plantlets were cultured on solid M2MS medium: without growth regulators and with 0.5 mg l^–1 BA. Plantlets that developed in liquid HTE media with 0.5 mg l^–1 GA₃ or 0.5 mg l^–1 GA₃ + 0.2 mg l^–1 BA produced 82–90% shoots on solid M2MS medium with 0.5 mg l^–1 BA after 50 days of culture.     

Effects of wastewater treatment plant effluents on freshwater mollusks in the upper Clinch River,Virginia, USA

Field and laboratory studies were conducted to determine mollusk distributions in proximity to waste-water treatment plants (WTP's) in the upper Clinch River and to test the tolerance of two mollusk species to monochloramine and unionized ammonia, the major toxicants in domestic effluent. River reaches up to 3.7 km downstream of WTP's were devoid of freshwater mussels (Unionidae), and tolerance to effluents varied among snails, sphaeriid clams, and the asian clam Corbicula fluminea. Residential communities with septic systems had no measurable impact on mollusk assemblages downstream.Laboratory bioassays with glochidia of Villosa iris yielded the following results: 24 h EC₅₀ and LC₅₀ values of 0.042 mg l^–1 and 0.084 mg l^–1 monochloramine, respectively; and 24 h EC₅₀ and LC₅₀ of 0.237 mg l^–1 and 0.284 mg l^–1 unionized ammonia, respectively. Glochidia rank among the most sensitive invertebrates in their tolerance to these toxicants. The snail Pleurocera unciale unciale was moderately sensitive, with 96 h LC₅₀ values of 0.252 mg l^–1 monochloramine and 0.742 mg l^–1 unionized ammonia. Monitoring of monochloramine and unionized ammonia concentrations 0.1 km below WTP outfalls indicated that monochloramine was the toxicant likely inhibiting mollusk recovery below these plants.The Unit is jointly supported by the U.S. Fish and Wildlife Service, Virginia Department of Game and Inland Fisheries, The Wildlife Management Institute and Virginia Polytechnic Institute and State University.     

Vegetative approach for improving the quality of water produced from soils in the westside of central California

Water reuse is a proposed strategy for utilizing or disposing of poor quality drainage water produced in the westside of central California. This 2-year field study evaluated the ability of two potential forage species to tolerate irrigation with water high in salinity, boron (B), and selenium (Se). The species used were: Sporobulus airoides var. salado (alkali sacaton) and Medicago sativa var. salado (alfalfa). After first year establishment with good quality water (<1 dS m^–1), the two species were furrow-irrigated with drainage effluent that had an average composition of sulfate-dominated salinity ((electrical conductivity (EC) of 6.2 dS m^–1)) B (5 mg l^–1), and Se (0.245 mg l^–1). Both crops were clipped monthly from June to October of each year. Total dry matter yields averaged between 11 and 12 mg ha^–1 for both crops irrigated with effluent for two growing seasons. Plant concentrations of Se ranged from a low of 1.3 mg kg^–1 in alkali sacaton to a high of 2.5 mg kg^–1 in alfalfa, while B concentrations ranged from a low of 60 mg kg^–1 in alkali sacaton to a high of 170 mg kg^–1 in alfalfa. Chemical composition of the soil changed as follows from preplant to post-irrigation after two seasons with drainage effluent: EC from 2.78 to 6.5 dS m^–1, extractable B from 1.9 to 5.6 mg l^–1, and no change in extractable Se at 0.012 mg l^–1 between 0 and 45 cm. Between 45 and 90 cm, EC values increased from 4.95 to 6.79 dS m^–1, extractable B from 2.5 to 4.8 mg l^–1, and no change in extractable Se at 0.016 mg l^–1. Increased salinity and extractable B levels in the soil indicate that management of soil salinity and B will be necessary over time to sustain long term reuse with poor quality water.     

Lactate content and lactate dehydrogenase activity inPalaemon serratus abdominal muscle during temperature changes

Summary Lactate concentration was measured in the abdominal muscle of the shrimpPalaemon serratus. Rapid and seasonal temperature changes result in an increase of the lactate content of approximately 3–4 fold.Lactate dehydrogenase from the abdominal muscle exhibits a temperature dependent pyruvate inhibition with pyruvate as substrate.The kinetic parameters of lactate dehydrogenase fromPalaemon serratus are found to vary during rapid temperature changes: V_max increases with temperature from 0.06 mol min^–1 (mg protein)^–1 at 10°C to 0.28 mol min^–1 (mg protein)^–1 at 30°C with lactate as substrate, and from 5.5 mol min^–1 (mg protein)^–1 at 10°C to 26.2 mol min^–1 (mg protein)^–1 at 30°C, with pyruvate (Table 1). The Hill coefficientn _H, decreases with temperature from 2.2 to 1.2 when the pyruvate reduction is examined, but remains near 1.2 when the activity is measured with lactate as substrate (Table 1). The S_0.5 values for lactate show a tendency to increase below 30 °C (18.9 mM l^–1 at 20 °C) whereas the S_0.5 for pyruvate is found to increase greatly with temperature (0.004 mM l^–1 at 10 °C and 0.06 mM l^–1 at 20 °C).Long term temperature changes involve variations of lactate dehydrogenase activity leading to inverse thermal compensation (Table 2).Activation energy (about 56 kJ both with pyruvate and lactate) does not vary during the year, suggesting that temperature adaptation does not induce important catalytic changes (Table 3).Abbreviation LDH lactate dehydrogenase     

Protein production from whey usingPenicillium cyclopium; growth parameters and cellular composition

Summary The growth parameters ofPenicillium cyclopium have been evaluated in a continuous culture system for the production of fungal protein from whey. Dilution rates varied from 0.05 to 0.20 h^–1 under constant conditions of temperature (28°C) and pH (3.5). The saturation coefficients in the Monod equation were 0.74 g l^–1 for lactose and 0.14 mg l^–1 for oxygen, respectively. For a wide range of dilution rates, the yield was 0.68 g g^–1 biomass per lactose and the maintenance coefficient 0.005 g g^–1 h^–1 lactose per biomass, respectively. The maximum biomass productivity achieved was 2 g l^–1 h^–1 biomass at dilution rates of 0.16–0.17 h^–1 with a lactose concentration of 20 g l^–1 in the feed. The crude protein and total nucleic acid contents increased with a dilution rate, crude protein content varied from 43% to 54% and total nucleic acids from 6 to 9% in the range of dilution rates from 0.05 to 0.2 h^–1, while the Lowry protein content was almost constant at approximately 37.5% of dry matter.Nomenclature (mg l^–1) C_o initial concentration of dissolved oxygen - (h^–1) D dilution rate - (mg l^–1) K₀₂ saturation coefficient for oxygen - (g l^–1) K_s saturation coefficient for substrate - (g g^–1 h^–1) lactose per biomass) m maintenance energy coefficient - (mM g^–1 h^–1O₂ per biomass) Q₀₂ specific oxygen uptake rate - (g l^–1) S residual substrate concentration at steady state - (g l^–1) S_o initial substrate concentration in feed - (min) t_1/2 time when C_o is equal to C_o/2 - (g l^–1) X biomass concentration - (g l^–1) X biomass concentration at steady state - (g g^–1 biomass per lactose) Y_G yield coefficient for cell growth - (g g^–1 biomass per lactose) Y_x/s overall yield coefficient - (h^–1) specific growth rate     

Effects of tissue culture conditions and explant characteristics on direct somatic embryogenesis in Oncidium `Gower Ramsey'

The effects of tissue culture conditions and explant characteristics on direct somatic embryogenesis were studied on Oncidium `Gower Ramsey'. Embryo formation was significantly affected by explant position. Leaf tip segments had a significantly higher embryogenic response than other segments of leaves. Adaxial-side-up orientation significantly promoted embryogenesis in comparison with abaxial-side-up orientation. There was no significant effect of sucrose in a range of concentrations (10–60 g l^–1). Modified 1/2-MS medium (containing 85 mg l^–1 KH₂PO₄) supplemented with 170 mg l^–1 NaH₂PO₄ significantly promoted direct somatic embryogenesis. Peptone at 0.5 mg l^–1 gave significantly higher emrbyogenic response (80%) on leaf tips than control treatment (50%). The best response on direct embryo formation was obtained on the modified 1/2-MS medium supplemented with 10–20 g l^–1 sucrose, 170 mg l^–1 NaH₂PO₄ and 0.5 g l^–1 peptone.     

Enzymatic pre-hydrolysis and anaerobic degradation of wastewaters with high fat contents

Dairy wastewaters containing elevated fat and grease levels (868 mg l^–1) were treated in an upflow anaerobic sludge blanket reactor (UASB) and resulted in effluents of high turbidity (757 nephelometric turbidity units), volatile suspended solids up to 944 mg l^–1 and COD removal below 50%. When the same dairy wastewater was pre-treated with 0.1% (w/v) of fermented babassu cake containing Penicillium restrictum lipases, turbidity and volatile suspended solids were decreased by 75% and 90%, respectively, and COD removal was as high as 90%.     

Biodegradation of nitrobenzene by a sequential anaerobic-aerobic process

Nitrobenzene was completely degraded by mixed cultures using a sequential anaerobic-aerobic treatment process. Under anaerobic conditions in a fixed-bed column aniline was formed from nitrobenzene through gratuitous reduction by cells of sewage sludge. This reaction was accelerated by the addition of glucose. Complete mineralization of aniline was accomplished by subsequent aerobic treatment using activated sludge as inoculum. The maximum degradation rate of nitrobenzene (4.5 mM) in the two-stage system was 552 mg l^–1d^–1, referring to 154 mg of nitrobenzene per gram of glucose. In a second experimental phase glucose as cosubstrate and H-donor was replaced by synthetic waste containing ethanol, methanol, isopropanol and acetone. Again, nitrobenzene (1.9 mM) was completely degraded (maximum degradation rate of 237 mg l^–d^–1, referring to 251 mg per gram of solvents). The major advantage of the described two-stage process is that the reduction of nitrobenzene by anaerobic pretreatment drastically reduces emission by stripping during aerobic treatment.Abbreviations HRT hydraulic retention time - OD₅₄₆ optical density at 546 nm     

Simultaneous nitrification and denitrification in a mixed methanotrophic culture

Simultaneous nitrification and denitrification using a mixed methanotrophic culture was investigated. When both NO₃ ^–-N (108 mg l^–1) and NH₃-N (59 mg l^–1) were added into batch reactors, nitrate removal was complete within 10 h at the rate of 47 mg NO₃ ^–-N g VSS^–1 day^–1 when dissolved oxygen (DO) concentration was maintained at 2 mg DO l^–1. Ammonia removal started simultaneously with nitrate removal at a slower rate of 14 NH₃-N g VSS^–1 day^–1. No significant accumulation of nitrite or nitrate during ammonia utilization suggested the occurrence of simultaneous nitrification and denitrification.     

Invertase and phosphatase of yeast in a phosphate-limited continuous culture

Summary Deficiency of inorganic phosphate caused the hyper production of invertase and the derepression of acid phosphatase in a continuous culture ofSaccharomyces carlsbergensis. The specific invertase activity was 40,000 enzyme units per g dry cell weight at a dilution rate lower than 0.05 h^–1 with a synthetic glucose medium of which the molecular ratio of KH₂PO₄ to glucose was less than 0.006. This activity is eight fold higher than in a batch growth and 1.5 fold as much as the highest enzyme activity observed so far in a glucose-limited continuous culture.For the hyper production of invertase, it is necessary to culture the yeast continuously by keeping the Nyholm's conservative inorganic phosphate concentration at less than 0.2 m mole per g dry weight cell. The derepression of acid phosphatase brought about by phosphate deficiency, was similar in both batch and continuous cultures.Nomenclature D dilution rate of continuous culture (h^–1) - E_i invertase concentration in culture (enzyme unit l^–1) - E_p acid phosphatase concentration in culture (enzyme unit l^–1) - P inorganic phosphate concentration in culture (mM) - S glucose concentration in culture (mM) - X cell concentration in culture (g dry weight cell l^–1) Greek Letter specific rate of growth (h^–1) Suffix f feed - 0 initial value     

Organic matter transport in an Appalachian Mountain river in Virginia,U.S.A.

Organic material transport in the New River, Virginia, was investigated over a 12 month period. Collections were made using drift nets and grab water samples from bridges at two sites about 210 km apart. About midway between the two sampling sites is a 1920 ha impoundment used for flood control and power generation. Dissolved organic matter (DOM) ranged 1–50 mg l^–1 at Site 1, upstream from the impoundment, and 11–19 mg l^–1 at Site 2 and was the most abundant form of organic matter at both sites during most periods of the year. Fine particulate organic matter (FPOM) ranged 1–45 mg l^–1 at Site 1 and 1–9 mg l^–1 at Site 2. Concentration of coarse particulate organic matter (CPOM) ranged 0.1–0.7 mg l^–1 at Site 1 and 0.1–0.2 mg l^–1 at Site 2. On an annual basis, the organic matter loads at Site 1 and Site 2 were computed to be 67 000 and 76 800 T y^–1, respectively, suggesting that the impoundment trapped and processed POM, and that municipal and industrial treatment facilities between the study sites supplemented DOM in the river.     

Acetate treatment in 70°C upflow anaerobic sludge-blanket (UASB) reactors: start-up with thermophilic inocula and the kinetics of the UASB sludges

This study focused on the use of thermophilic anaerobic granulae in the start-up of 70°C acetate-fed upflow anaerobic sludge-blanket (UASB) reactors and the kinetics of granulae grown at 70°C. In the UASB reactors, chemical oxygen demand removal commenced within 48 h of the start-up. The maximum reduction in chemical oxygen demand was 84% with the feed containing yeast and 71% without a yeast supplement. In the bioassays, the yeast-grown sludge converted 98% of the acetate consumed to methane as compared to 92% for the sludge grown without yeast. The highest initial specific methane production rate (µ_{CH 4}) of the UASB sludges grown at 70°C was 0.088 h^–1 at an acetate concentration of 4.6 mM. The higher initial acetate concentration was found to prolong the lag-phase in methane production significantly and to decrease the µ_{CH 4}. The half-saturation constant (K _s), the inhibition constant (K _i), the inhibition response coefficient (n), and the µ_{CH 4} ^max, calculated according to a modified Haldane equation, were 1.5 mM, 2.8 mM, 0.8, and 0.28 h^–1, respectively. The prolonged starvation of the 70°C sludge (15 days) decreased the µ_{CH 4} from about 0.022 h^–1 to 0.011 h^–1 and increased the lag phase in methane production from 6 h to 24 h as compared to non-starved sludge.