Showing papers on "Effluent published in 1991"

Giardia and Cryptosporidium spp. in filtered drinking water supplies.

Abstract: Giardia and Cryptosporidium levels were determined by using a combined immunofluorescence test for filtered drinking water samples collected from 66 surface water treatment plants in 14 states and 1 Canadian province. Giardia cysts were detected in 17% of the 83 filtered water effluents. Cryptosporidium oocysts, were observed in 27% of the drinking water samples. Overall, cysts or oocysts were found in 39% of the treated effluent samples. Despite the frequent detection of parasites in drinking water, microscopic observations of the cysts and oocysts suggested that most of the organisms were nonviable. Compliance with the filtration criteria outlined by the Surface Water Treatment Rule of the U.S. Environmental Protection Agency did not ensure that treated water was free of cysts and oocysts. The average plant effluent turbidity for sites which were parasite positive was 0.19 nephelometric turbidity units. Of sites that were positive for Giardia or Cryptosporidium spp., 78% would have been able to meet the turbidity regulations of the Surface Water Temperature Rule. Evaluation of the data by using a risk assessment model developed for Giardia spp. showed that 24% of the utilities examined would not meet a 1/10,000 annual risk of Giardia infection. For cold water conditions (0.5 degree C), 46% of the plants would not achieve the 1/10,000 risk level.

Irrigation with Treated Sewage Effluent: Management for Environmental Protection

Abstract: Properly treated sewage effluent becomes an alternative source of irrigation water, and at the same time provides a convenient means of sewage disposal. The object of this volume is to provide the reader with a comprehensive overview of the principles and practices of irrigation with treated sewage effluent. Special emphasis is placed on the arid quality of the water (eg pathogenic organisms, salt and nutrients). The authors describe the main components of effluent-soil-plant systems involved in the development of appropriate irrigation, fertilization and crop management.

Occurrence of organotins in municipal wastewater and sewage sludge and behavior in a treatment plant

Abstract: THe behavior of selected organotin species in a wastewater treatment plant of Zurich, Switzerland, was studied. In untreated wastewater, monobutyltin (MBT), dibutyltin (DBT), and tributyltin (TBT) were detected in the range of 136-564, 127-1,026, and 64-217 ng/L, respectively, of which 81-92% were associated with suspended solids. During treatment, the fraction of organotins in the particulate phase decreased with decreasing suspended solids concentration. All organotin species monitored were found to be efficiently removed from wastewater, mainly by sedimentation in the primary clarifier. In the secondary effluent, levels of different organotins were in the range of 7-47 ng/L. These compounds were transferred into sewage sludge, indicating that the most important process for the elimination of organotins was adsorption into sludge. Residues of MBT, DBT, and TBT in digested sludges were in the range of 0.10-0.97, 0.41-1.24, and 0.28-1.51 mg/kg (dry weight), respectively.

Effect of sodium chloride on transport of bacteria in a saturated aquifer material.

Abstract: Determinations were made of the influence of NaCl concentration, cell density, and flow velocity on the transport of Pseudomonas sp. strain KL2 through columns of aquifer sand under saturated conditions. A pulse-type boundary condition was used. The experiments were conducted by using 0.3-m-long Plexiglas columns with an internal diameter of 0.05 m. When a 1-h pulse of a 0.01 M NaCl solution containing 10(8) cells per ml was added at a flow rate of 10(-4) m s-1, the bacterial density in the effluent never exceeded 2.2% of the density of cells added, and only 1.5% of the bacteria passed through the aquifer material. In contrast, when the bacteria were applied in distilled water, the relative cell density in the effluent approached 100%, and 60% of the bacteria were transported through the aquifer solids. Under these conditions, the breakthrough of Pseudomonas sp. strain KL2 was slower than chloride. When the flow rate was 2.0 x 10(-4) m s-1, the cell density in the effluent reached 7.3% of that added in 0.01 M NaCl solution, but only 3.9% of the bacteria were transported through the aquifer particles. On the other hand, the density in the effluent approached 100% of that added in deionized water, and 77% of the added bacteria were recovered. When the density of added cells was 10(9) cells per ml at a flow rate of 10(-4) m s-1, the densities in the effluent reached 70 and 100% of those added in salt solution and deionized water, respectively, and 44 and 57% of the bacteria were transported through the aquifer solids.(ABSTRACT TRUNCATED AT 250 WORDS)

Supercritical water oxidation process of organics with inorganics

Abstract: A method and apparatus is disclosed for oxidation of aqueous mixtures of organic material, including toxic material in the presence of inorganic materials, by reaction of said material with water and oxygen at supercritical conditions. Oxygen and the aqueous mixture are separately pressurized to greater than about 218 atmospheres, combined to form a reaction mixture and then directed through a tubular reactor having a substantially constant internal diameter. The velocity of the reaction mixture is sufficient to prevent settling of a substantial portion of solids initially present in the reaction mixture and of solids which form during passage through the reactor. The mixture is heated to temperature above about 374° C. in the tubular reactor. A substantial portion of the organic material in the reaction mixture is oxidized in the tubular reactor to thereby form an effluent mixture. Inorganic salts in the effluent mixture, which are insoluble at conditions of supercritical temperature and pressure for water, are dissolved in a liquid water phase during cooldown of the effluent mixture at an outlet end of the reactor. Inorganic solids that are not soluble in the effluent mixture can be separated from a substantial portion of the effluent mixture by filtration prior to subsequent depressurization of the effluent mixture.

Degradation of chlorinated lignin compounds in a bleach plant effluent by the white-rot fungus trametes versicolor

Abstract: Chlorinated lignin derivatives in a combined bleach plant effluent from sulphite pulping were degraded by several white-rot fungi among which Trametes versicolor (Coriolus versicolor) strains were the most efficient. With glucose as co-substrate, about 90% colour reduction was achieved within 3 days. Simultaneously, the concentration of chloro-organic compounds measured as adsorbable organic halogens decreased by about 45%. As shown by gel chromatography, the high-molecular-weight fraction in the effluent was completely depolymerized while over 50% of total aromatic compounds were degraded. The presence of a co-substrate was necessary for all these activities of the fungus. The residue obtained after degradation was extremely recalcitrant and not further degradable.

Fructose oleate synthesis in a fixed catalyst bed reactor

Abstract: Fructose oleate undergoes continuous synthesis in a fixed catalyst bed reactor using an industrial fixed lipase. The effects of the time spent in the reactor, substrate concentration and effluent recycling are studied. A yield of 83% is obtained by recycling the effluent 3 times.

Subsurface microirrigation with effluent

Abstract: Field crops such as cotton, wheat, corn, and peas have been irrigated with treated domestic effluent for five years by a subsurface trickle system. For four years the experiments were conducted in the same field without replacing any components of the irrigation system. According to the field results it was found that a subsurface system can be used without failures for years. Emitter clogging by plant roots was prevented by Treflan injection. The uniformity of plants in the experimental plots indicated that the effluent water was well distributed in the soil. Increased yields, as compared to microirrigation systems with emitters on the soil surface, were obtained with subsurface micro irrigation.

Treating contaminated effluents and groundwaters

Abstract: A method of treating a liquid effluent or groundwater containing organic contaminants is provided. The liquid effluent or groundwater containing the organic contaminants is contacted with hydrogen peroxide and transition metal ions. The hydrogen peroxide and transition metal ions are present in effective amounts based on the concentration of the organic contaminants in the liquid effluent or groundwater. The liquid effluent or groundwater is then irradiated with UV light having a polychromatic output between about 200 to 400 nm to decompose the organic contaminants. The ratio of hydrogen peroxide to transition metal ions is selected so as to favour the absorption of UV light by the hydrogen peroxide in the irradiation step.

Membrane extraction mass spectrometry for the on-line analysis of gas and liquid process streams

Abstract: A membrane extraction maw spectrometry (MEMS) tech& que was developed for the on-line analyrk of organlc components of multiple liquid and gas dreams. Sllkone hollowfiber “branos allow for the extrcrctkn of orgalc chedcdr from compkx ad dMy matrices wtth no sampk preparrdkn. MWpk dreams of both air ad water were analyzed orrllne wlth a dngk analyzer. TM6 method has been appUed In an aerobic blologlcal wastewater treatment process. Maw balance determinations were performed by quantltatlvdy measuring HH organlc contaminants In tha lnfiumt wastewater dream, In the effluent water stream, and In the effluent air stream.

A new process for the microbial removal of sulphate and heavy metals from contaminated waters extracted by a geohydrological control system

Abstract: TLe underlying groundwater of many well established metal-refining sites are contaminated with sulphate and heavy metals. Geohydrological control systems are being developed to prevent the spreading of the contamination. These systems produce an effluent which has to be purified before it can be discharge to the environment or reused as process water. An an aerobic sulphate-reducing microbial process to treat such waters has been evaluated in a 9 m 3 pilot plant after a 2 year research programme. The process uses ethanol as the microbial growth substrate and energy source for sulphate reduction which leads to precipitation of heavy metal sulphides. The pilot plant successfully demonstrated that this process removes sulphate and a wide range of heavy metals to acceptable levels allowing the aqueous effluent to be discharged safely

Toxicity tests of effluents with marsh plants in water and sediment

Abstract: Methods are described for toxicity testing of water and sediment with two varieties of the freshwater marsh plant Echinochloa crusgalli (Linneaus) Palisot de Beauvois (Poaceae), and complex effluents. Two tests are described: a seed germination and early seedling growth test in water, and a survival and seedling growth test in natural and synthetic sediments. Effects of effluents from a sewage treatment plant, tannery, textile mill, pulp and paper mill, coking plant and sewage treatment plant included inhibition of germination, chlorophyll synthesis and growth. The tests with rooted marsh plants were sensitive to pollutants and detected toxicity of a range of pollutants in water and sediment. Synthetic sediments similar to natural sediments allowed toxicity tests to be done under carefully controlled conditions of particle size distribution, organic content, pH, electrode potential (Eh) and cation exchange capacity (CEC).

Effects of biologically treated bleached kraft mill effluent on cold water stream productivity in experimental stream channels

Abstract: Large-scale outdoor experimental streams were used in a series of effluent addition studies to determine the compatibility of biologically treated bleached kraft mill effluent with satisfactory production of salmonid fishes. Results are reported for 9- to 10-month studies at effluent concentrations representing from 0.5 to 2.0 mg/L of effluent 5 d biochemical oxygen demand (BOD5) addition (1.3–5.1% v/v), as well as for an extended 3.5-year study at 0.5 BOD5 addition (1.5% v/v). The series of studies indicated a pattern of greater rainbow trout (Oncorhynchus mykiss) cumulative production and average weight in streams receiving effluent and better survival in the control streams. The final long-term study also indicated that successful maturation, spawning, hatching, larval development, and juvenile growth could take place during conditions of continuous effluent exposure. Measurements of the supporting food web suggest that effluent can increase periphyton production at low concentrations through nutrient additions but that higher effluent concentrations may reduce periphyton production due to the effect of color on underwater light transmittance. Macroinvertebrate populations increased in the streams receiving effluent.

Use of fractionation procedures and extensive chemical analysis for toxicity identification of a chemical plant effluent

Abstract: As a part of a National Pollutant Discharge Elimination System (NPDES) biomonitoring program a series of toxicity tests was conducted with process water from a chemical plant using Ceriodaphnia dubia and Pimephales promelas. There were marked differences among the two tested species. The acute (LC50) values from 96-h static toxicity tests with Pimephales promelas were always lower (higher toxicity) than the values obtained from the invertebrate tests. The concentration of ammonia in the effluent, particularly its un-ionized form (250 mg NH4-N/L, which represents 0.7 mg NH3-N/L), was above the threshold concentration for most freshwater species and therefore was the primary suspect of the toxicity present in the effluent. Prior to initiation of the toxicity identification evaluation (TIE) program, chemical analyses that included measurements of inorganic and organic parameters were conducted with the effluent. During the TIE fractionation, a portion of the sample was purged with nitrogen to remove volatile organics, and a second portion of the sample was pressure-filtered through a 0.45-μm filter. Because toxicity equal to the whole sample was found in these fractions, a portion of the inorganic fraction was subfractionated into zeolite, clinoptilolite, activated carbon, pH-adjustment, aeration, and cation fractions. The results of these tests confirmed that ammonia played a role in the sample's toxicity. However, when ammonia was removed from the effluent sample, toxicity was still present. Next organic chemicals were fractionated as suspected sources of toxicity. At first, organics were removed from the effluent by passing the filtered sample over an XAD-resin column. Because a portion of the reconstituted organic fraction was toxic, the organic fraction was subfractionated further by extracting with dichloromethane at pH > 11, pH < 2, and pH 7.1. The dichloromethane extracts were toxic, whereas the aqueous portions were not toxic. The neutral extract, which was more toxic than the basic and acidic extract, was further fractionated by using HPLC. Seventeen HPLC fractions were isolated and tested for toxicity to determine which constituent(s) were responsible for the observed whole effluent toxicity.