Showing papers on "Effluent published in 1993"

F-specific RNA bacteriophages are adequate model organisms for enteric viruses in fresh water.

Abstract: Culturable enteroviruses were detected by applying concentration techniques and by inoculating the concentrates on the BGM cell line. Samples were obtained from a wide variety of environments, including raw sewage, secondary effluent, coagulated effluent, chlorinated and UV-irradiated effluents, river water, coagulated river water, and lake water. The virus concentrations varied widely between 0.001 and 570/liter. The same cell line also supported growth of reoviruses, which were abundant in winter (up to 95% of the viruses detected) and scarce in summer (less than 15%). The concentrations of three groups of model organisms in relation to virus concentrations were also studied. The concentrations of bacteria (thermotolerant coliforms and fecal streptococci) were significantly correlated with virus concentrations in river water and coagulated secondary effluent, but were relatively low in disinfected effluents and relatively high in surface water open to nonhuman fecal pollution. The concentrations of F-specific RNA bacteriophages (FRNA phages) were highly correlated with virus concentrations in all environments studied except raw and biologically treated sewage. Numerical relationships were consistent over the whole range of environments; the regression equations for FRNA phages on viruses in river water and lake water were statistically equivalent. These relationships support the possibility that enteric virus concentrations can be predicted from FRNA phage data.

Effect of Water Exchange Rate on Production, Water Quality, Effluent Characteristics and Nitrogen Budgets of Intensive Shrimp Ponds

Abstract: Water exchange is routinely used in shrimp culture. However, there are few, if any, systematic investigations upon which to base exchange rates. Furthermore, environmental impacts of pond effluent threaten to hinder further development of shrimp farming in the U.S. The present study was designed to determine effects of normal (25.0%/d), reduced (2.5%/d) and no (Oo/o/d) water exchange on water quality and production in intensive shrimp ponds stocked with Penaeus serverus at 44 postlarvae/m2. Additional noexchange ponds were stocked with 22 and 66 postlarvae/m* to explore density effects. Water exchange rates and stocking density influenced most water quality parameters measured, including dissolved oxygen, pH, ammonia, nitrite, nitrate, Kjeldahl nitrogen, soluble orthophosphate, biochemical oxygen demand, phytoplankton and salinity. Reduced-exchange and no-exchange treatments resulted in reduced potential for environmental impact. Mass balance of nitrogen for the system indicates that 13-46% of nitrogen input via feed is lost through nitrification and atmospheric diffusion. Growth and survival were excellent in ponds with normal exchange, reduced exchange, and a combination of low density with no water exchange. A combination of higher stocking density and no water exchange resulted in mass mortalities. Mortalities could not be attributed to a toxic effect of any one water quality parameter. Production was 6,400 kg/ha/crop with moderate stocking density (44/m2) and reduced (2.5%/d) water exchange and 3,200 kg/ha/crop with lower stocking density (22/m2) and no water exchange. Results indicate that typical water exchange rates used in intensive shrimp farms may be drastically reduced resulting in a cost savings to farms and reduced potential for environmental impact from effluent.

Decolorization of industrial effluents containing reactive dyes by actinomycetes.

Abstract: Actinomucete strains have been identified which decolorize effluents containing different types of reactive dyes. Adsorption of anthraquinone, phthalocyanine and azo dyes to the cells of some of the strains resulted in the decolorization of the effluents, but no degradation of the dyes was observed. In contrast, effluents containing an azo-copper complex and a formazan-copper complex dye were almost completely decolorized by several of the strains without adsorption to the cells. The observed changes in the visible spectra indicated a degradation during incubation with she strains.

Fate of linear alkylbenzene sulfonate in the environment

Abstract: An extensive monitoring study was conducted to determine the fate of linear alkylbenzene sulfonate (LAS) during wastewater treatment and in the environment. Results showed that LAS was highly removed during activated sludge (99.3 ± 0.6%), lagoon (98.5 ± 1.8%), oxidation ditch (98.0 ± 4.2%), and rotating biological contact (96.2 ± 6.1%) treatment, with poorer removals observed at trickling filter (77.4 ± 15.5%) facilities. Concentrations of LAS in anaerobically digested sludge (10,462 ± 5170 μg/g) were one to two orders of magnitude greater than those observed for aerobically digested sludge (152 ± 119 μg/g), illustrating that LAS is rapidly degraded during aerobic sludge treatment. Receiving water concentrations of LAS in rivers of low effluent dilution were generally < 50 μg/L. Elevated river sediment concentrations of LAS were observed only below the outfall of trickling filter treatment plants (59.7-182.1 μg/g). Alkyl chain lengths of LAS averaged 12.0 carbon units in most environmental compartments, with the exception of sludge solids and river sediments, in which an enrichment of longer chain lengths was observed. Measured concentrations of LAS in river waters under critical low flow conditions were in agreement with PG-GRiDS model predictions [5], thus supporting the validity of the modeling approach.

Influence of Phosphorus in Rainbow Trout Diets on Phosphorus Discharges in Effluent Water

Abstract: Two experiments were conducted with rainbow trout Oncorhynchus mykiss to investigate the influence of several diets and supplemental phosphorus on discharges of phosphorus in hatchery effluent water. A diet was formulated to contain no fish meal and a reduced level of non-phytin phosphorus (approximately 0.9%) provided, in part, by supplemental defluorinated rock phosphate, which has a low solubility in water. Feeding rainbow trout this diet supported 86% of the growth attained with a conventional hatchery diet while discharges of phosphorus in the effluents decreased by 40–51%.

Ion chromatography system using electrochemical suppression and detector effluent recycle

Abstract: A method of streamlining and lowering the cost of operation of ion chromatography as well as improving detection limits is disclosed. The apparatus includes chromatographic separating means through which a sample is eluted in an eluent solution including an electrolyte. The apparatus includes suppressor means having a chromatography effluent compartment means separated from a detector effluent compartment means by an ion exchange membrane, forming a chromatography effluent flow channel and a detector effluent channel, respectively. Electrode means are disposed in communication with both flow channels for passing an electric current transverse to the solution that is passing through them. The chromatography effluent flows through the chromatography effluent flow channel of the suppressor and through detector means which detects resolved ionic species therein. The effluent from the detector means is then recycled through the detector effluent flow channel and forms a sump for electrolyte ions passing across the chromatography effluent as well as supplying the water for the electrolysis reaction generating acid (or base) for suppression.

Ultraviolet disinfection for wastewater reclamation and reuse subject to restrictive standards

Abstract: An ultraviolet (UV) disinfection system was operated under field conditions using both unfiltered and filtered secondary wastewater effluents to assess the feasibility of using UV light to meet the stringent criterion specified in the California Wastewater Reclamation Criteria (CWRC). In the unfiltered wastewater, the CWRC criterion that the 7-day median not exceed 23 total coliform/100 mL was met consistently in effluent exposed to an average UV dose of 60 mW.s/cm 2 or greater. In the filtered wastewater, the CWRC criterion that the 7-day median not exceed 23 total coliform/100 mL was met consistently in effluent exposed to an average UV dose of 48 mW.s/cm 2 or greater.

Strategy using bioreactors and specially selected microorganisms for bioremediation of groundwater contaminated with creosote and pentachlorophenol

Abstract: A two-stage, continuous-flow, sequential inoculation bioreactor strategy for the bioremediation of ground water contaminated with creosote and pentachlorophenol (PCP) was evaluated at the bench- and pilot-scale levels. Performance of continually stirred tank reactors (CSTR) using specially-selected microorganisms was assessed according to chemical analyses of system influent, effluent and bioreactor residues, performing a mass balance evaluation, and comparative biological toxicity and teratogenicity measurements. When specially-selected bacteria capable of utilizing (mineralizing) high-molecular-weight polycyclic aromatic hydrocarbons (HMW PAHs) as primary growth substrates were used in pilot-sale bioreactors (120 gal), the concentration of creosote constituents was reduced from ca. 1,000 ppm in the ground water feed (flow rate = 30 GPD) to 99%). Notably, the cumulative concentration of 8 HMS PAHs (containing 4 or more fused rings) was reduced from 368 ppm in the ground water fed to 5.2 ppm in the system effluent. Moreover, the toxicity and teratogenicity of the bioreactor effluent was significantly reduced. Biodegradation of PCP was limited (ca. 18%) due in large part to poor inoculation and a high degree of abiotic loss (bioaccumulation and adsorption). In general, field data correlated well with those obtained from bench-scale studies.

Volatile Flavor Components in Snow Crab Cooker Effluent and Effluent Concentrate

Abstract: Volatile compounds in snow crab cooker effluent (SCCE) and effluent concentrate (EC) were compared by simultaneous steam distillation-solvent extraction/gas chromatography/mass specirometry (SDE/GC/ MS). Volatile compounds (122) were detected in both samples. Of these, 97 were positively identified, composed mainly of nitrogen-and sulfur-containing compounds, aromatic hydrocarbons, aldehydes, ketones, furans, and alcohols. A total of 101 compounds were detected in the cooker effluent, and 90 were detected in the concentrate. Amounts of sulfur- and nitrogen-containing compounds were 44 and 7.3 times higher, respectively, in EC.

Assessing the Effects of Storage Tank Design on Water Quality

Abstract: A study was conducted to assess the effects of storage tank design and operation on mixing regimes and effluent water quality. The influent and effluent flows of three tanks with diameter-to-height ratios ranging from 3.5:1 to 0.4:1 were monitored for chlorine residual. Chlorine levels were also measured within the water column of each tank. Although chlorine profiles revealed some stratification in tanks with large height-to-diameter ratios, completely mixed models were more accurate than plug-flow models in representing the mixing behavior of all three tanks. Modeling further indicated that the quality of the effluent from completely mixed tanks deteriorated with decreasing volumetric change. Standpipes were the least desirable tank design with respect to effluent water quality

Process and device for catalytic dehydrogenation of a C2+ paraffinic charge comprising means for inhibiting the freezing of water in the effluent

Abstract: A process and a device for the catalytic dehydrogenation of a C 2+ paraffinic hydrocarbon charge is applicable to the synthesis of methyl tert-butyl ether. Effluent coming from the dehydrogenation reactor and containing olefins and water is cooled in at least one heat exchanger (41), saturated with water in a column (3) and sent to a stripping column (10) where it is at least partly put in contact with a recycled aqueous liquid phase containing a solvent, preferably methanol. The compressed gaseous effluent in which the water is thereby inhibited from freezing by the methanol is cooled in a heat exchanger (13) then separated in separator (8) into olefins and into hydrogen. An aqueous liquid phase with methanol is decanted at (8) and recycled in column (10).

Apparatus for purifying a liquid effluent containing pollutants

Abstract: The invention relates to an apparatus for the purification of a liquid effluent containing pollutants, particularly metals and/or radionuclides, as well as to a process for purifying the effluent. An object of the invention is to provide a continuously functioning purifying apparatus. This object is achieved with the aid of an apparatus incorporating a confinement enclosure containing a support in which are immobilized living cells of photosynthetic microorganisms. The support is made from a material transparent to light rays. The apparatus also incorporates a mechanism for introducing and circulating the effluent to be treated and a culture medium within the enclosure.