Showing papers on "Effluent published in 1998"

Identification of Estrogenic Chemicals in STW Effluent. 1. Chemical Fractionation and in Vitro Biological Screening

Abstract: A fractionation system, combined with an in vitro assay for detecting estrogenic activity, was developed in order to isolate and identify the major estrogenic chemicals present in seven sewage-treatment works (STW) effluents, receiving primarily domestic effluent, discharging into British rivers. Three sterols were isolated from estrogenic fractions of sewage extracts; these were the natural hormones 17β-estradiol and estrone and the synthetic hormone 17α-ethynylestradiol. 17β-Estradiol and estrone were present in all the effluents at measured concentra tions ranging from 1 ng/L to almost 50 and 80 ng/L, respectively. The concentration of 17α-ethynylestradiol was generally below the limit of detection but was positively identified in three of the effluent samples at concentrations ranging from 0.2 to 7.0 ng/L. These data suggest that natural and synthetic hormones may be responsible for the observed induction of vitellogenin synthesis in male fish placed downstream of effluent discharges from STWs that re...

Limits to Growth

Abstract: Urban, industrial and agricultural wastewaters contain up to three magnitudes higher concentrations of total nitrogen and phosphorous, compared with natural water bodies.1 Normal primary and secondary treatment of these wastewaters eliminates the easily settled materials and oxidizes the organic material present, but does not remove the nutrients which will cause eutrophication of the rivers or lakes into which these wastewaters may be discharged. Tertiary treatment of the effluent is therefore required, and both chemical and physical methods which are used are very expensive. Oswald2 estimates that the relative cost of tertiary treatment to remove PO 4 3− , NH 4 + and NO 3 − is about 4 times the cost of primary treatment. Higher orders of treatment, such as quaternary treatment required to remove refractory organics and organic and inorganic toxicants and quinary treatment to remove inorganic salts and heavy metals, are 8 to 16 times as expensive as primary treatment. Algae can be used as a biological alternative tertiary treatment and also for the removal of heavy metals and possibly other toxic substances.3,4 The possibility exists that the algae produced in these systems can be used as animal feed supplements,5,6 or be composted. The use of waste-grown algae may ultimately also have application in closed cycle life-support systems,7,8 or may be used in conjunction with power stations, not only to treat wastewaters, but also to act as a CO2 sink for the amelioration of the impact of greenhouse gases.9–13

Small and decentralized wastewater management systems

Abstract: 1 Decentralized Wastewater Management Systems and Management 2 Constituents in Wastewater 3 Fate of Wastewater Constituents in the Environment 4 Introduction to Process Analysis and Design 5 Wastewater Pretreatment Operations and Processes 6 Alternative Wastewater Collection Systems 7 Biological Treatment and Nutrient Removal 8 Pond Treatment Systems 9 Wetlands and Aquatic Treatment Systems 10 Land Treatment Systems 11 Intermittent and Recalculating Medium Filters 12 Effluent Repurification and Reuse 13 Effluent Reuse and Disposal for Decentralized Systems 14 Biosolids and Septage Management 15 Management of Decentralized Wastewater Systems Appendixes

Antibiotic Resistance in Acinetobacter spp. Isolated from Sewers Receiving Waste Effluent from a Hospital and a Pharmaceutical Plant

Abstract: The possible increase of antibiotic-resistant bacteria in sewage associated with the discharge of wastewater from a hospital and a pharmaceutical plant was investigated by using Acinetobacter species as environmental bacterial indicators. The level of susceptibility to six antimicrobial agents was determined in 385 Acinetobacter strains isolated from samples collected upstream and downstream from the discharge points of the hospital and the pharmaceutical plant. Results indicated that while the hospital waste effluent affected only the prevalence of oxytetracycline resistance, the discharge of wastewater from the pharmaceutical plant was associated with an increase in the prevalence of both single- and multiple-antibiotic resistance among Acinetobacter species in the sewers.

Anaerobic treatment of sulphate-rich wastewaters.

Abstract: Until recently, biological treatment of sulphate-rich wastewater was rather unpopular because of the production of H2S under anaerobic conditions. Gaseous and dissolved sulphides cause physical-chemical (corrosion, odour, increased effluent chemical oxygen demand) or biological (toxicity) constraints, which may lead to process failure. Anaerobic treatment of sulphate-rich wastewater can nevertheless be applied successfully provided a proper treatment strategy is selected. The strategies currently available are discussed in relation to the aim of the treatment: i) removal of organic matter, ii) removal of sulphate or iii) removal of both. Also a whole spectrum of new biotechnological applications (removal of organic chemical oxygen demand, sulphur, nitrogen and heavy metals), recently developed based on a better insight in sulphur transformations, are discussed.

Removal, partitioning, and fate of silver and other metals in wastewater treatment plants and effluent-receiving streams

Abstract: We investigated the removal of silver in five publicly owned treatment works (POTWs) and the fate of Ag in effluent receiving streams. Comparisons were made to several other metals. Silver was removed efficiently (>94%) in all POTWs. The percentage of total Ag removed was independent of the influent Ag concentration, while the concentration of Ag in effluents was directly related to influent concentration. A good correlation (r 2 =0.77) between metal removal (%) and partition coefficient (K d ) indicated that differences among metals in removal efficiency were controlled mainly by metal partitioning (sorption) to particles removed by settling and/or filtration. A large fraction (19-53%) of Ag in the filterable ( 0.05 μm), and the percentage filterable Ag was directly related to DOC concentration (r 2 =0.96). Effluent Ag concentrations (0.06-2.6 μg/L) were several orders of magnitude higher that typical background stream levels (1-2 ng/L), but Ag discharged to streams was rapidly dissipated by dilution and incorporation into stream sediments.

Chloride/Bromide and Chloride/Fluoride Ratios of Domestic Sewage Effluents and Associated Contaminated Ground Water

Abstract: To establish geochemical tools for tracing the origin of ground water contamination, we examined the variations of Cl/Br and Cl/F (weight) ratios in (1) domestic waste water from the Dan Region Sewage Reclamation Project and from reservoirs in the central coast of Israel; (2) associated contaminated ground water; and (3) pristine ground water from the Mediterranean coastal aquifer of Israel. Our data show that supply water, anthropogenic NaCl and fluoridation control the Cl/Br (410 to 873) and Cl/F (468 to 1070) ratios of domestic waste water, and conventional sewage treatment does not affect the anthropogenic inorganic signals. The Cl/Br ratios of ground water contaminated with sewage effluent reflect conservative mixing proportions of sewage and regional ground water components. Sensitivity tests demonstrate that it is possible to detect and distinguish sewage contamination from marine ratios after a sewage contribution of 5 to 15% is mixed with regional ground water. Mixing with Br-enriched fresh water (e.g., Sea of Galilee; Cl/Br=145), however, would reduce this sensitivity. Since the high Cl/Br signal of sewage effluents is distinguishable from other anthropogenic sources with low Cl/Br ratios (e.g., street runoff, agriculture return flows) and from natural contamination sources (e.g., salt water intrusion; Cl/Br=293), Cl/Br ratios can therefore be a useful inorganic tracer for identification of the origin of contaminated ground water. The Cl/F ratios of sewage-contaminated ground water (284 to 5186) were higher than those in the original sewage effluent, which suggests retention of fluoride into the aquifer solid phase.

>Removal of Lead from Wastewater Using Bagasse Fly Ash—A Sugar Industry Waste Material

Abstract: Bagasse fly ash, a waste generated in sugar industries in India, has been converted into a low cost adsorbent and has been used for the removal of lead from aqueous solutions in the 4.80 A 10â4 to 4.83 A 10â3 M concentration range. Maximum removal takes place at pH 3.0 using lOgâ1 of the adsorbent of particle size 150–200 mesh. The effect of the presence of other metal ions, temperature, and contact time has also been studied. Sorption data have been correlated with both Langmuir and Freundlich adsorption models. The adsorbent has been satisfactorily.-used for the removal of Pb2+ from the effluent of a metal-finishing plant.

Designing for the Interactions Between Water-Use and Effluent Treatment

Abstract: This paper addresses the interactions between the design of water-using operations and effluent treatment in the process industries. Water use can be minimized though re-use or recycling. Treatment of water can be for discharge or to enable further re-use or recycling. Targets have previously been established for minimum flowrate of water in waterusing operations and minimum flowrate to be treated through the use of distributed (or segregated) effluent treatment. Design methods have also been presented to allow the targets to be achieved in practice. However, these methods were based on each part of the problem taken in isolation. A new methodology is presented in this paper which allows design options to be explored which take into account the interactions between different parts of the overall problem.

Synthetic Fibers as Indicators of Municipal Sewage Sludge, Sludge Products, and Sewage Treatment Plant Effluents

Abstract: Because of concerns regarding health, safety, and aesthetics, a test that identifies the presence of sewage sludge or its products (biosolids) in commercial materials such as soil conditioners and composts would be useful. This test could also trace the effluent plume from a sewage treatment plant. We have discovered that synthetic fibers serve as such an indicator. Synthetic fibers are abundant in sludge, sludge products, and sewage treatment plant effluents. The fibers evidently are introduced from clothes-washing machines and survive the sewage treatment process. Synthetic fibers were identified using polarized light microscopy, which provided a simple, rapid method for determining the presence or absence of municipal sewage sludge or its products. False positives or false negatives have not occurred with any of the materials examined so far. We also monitored synthetic fibers in surface sediments of Huntington Harbor, Long Island, NY, a harbor receiving the effluent from a trickling filter sewage treatment plant. Fibers generally decrease in size and abundance with distance from the source. In Oyster Bay Harbor, Long Island, an advanced sewage treatment plant is operated with a final microfiltration step. Synthetic fibers are less abundant in the sediments of this harbor.

Production of Soluble Microbial Products (SMP) in an Anaerobic Baffled Reactor: Composition, Biodegradability, and the Effect of Process Parameters

Abstract: The composition and biodegradability of effluents from biological treatment plants is of increasing interest due to tightening effluent standards. One of the main constituents of effluents are soluble microbial products (SMPs) produced in the reactor during metabolism and endogenous decay. The objective of this preliminary work was to examine the influence of operating parameters such as temperature, hydraulic retention time (HRT), and organic loading rate (OLR) on the production of SMPs in a compartmentalised anaerobic baffled reactor (ABR) fed a simple sucrose-nutrients substrate. In addition, in order to gain greater insight into the SMPs produced, the composition and anaerobic biodegradability of various molecular weight fractions were analysed. It was found that decreasing operating temperature resulted in slight increases in SMP production, a decreased rate of degradation, and hence increases in effluent SMPs. In addition, decreasing HRTs, and increasing OLRs, also resulted in increased effluent SMP...

Decolorization and biodegradation of anerobically digested sugarcane molasses spentwash effluent from biomethanated plant by white-rot fungi

Abstract: Abstract Four white-rot fungal cultures were examined for their ability to decolorize and bioremediate anaerobically digested molasses spent wash (DMSW) generated by biomethanation plants. Two cultures Coriolus versicolor and Phanerochaete chrysosporium showed an ability to decolorize and reduce the chemical oxygen demand (COD) of diluted DMSW (12·5% v/v). Both cultures required an additional labile carbon source to carry out decolorization while additional organic nitrogen did not significantly improve it further. Optimum growth and decolorization occurred at 35–40°C, pH 5·0, glucose at 3–5%(w/v). Maximum decolorization (71·5 and 53·5%) and COD reduction (90·0 and 73·0%) were achieved in 6·25% (v/v) DMSW medium by C. versicolor and P. chrysosporium , respectively. These values decreased significantly at higher concentrations of DMSW (12·5 and 25% v/v), nevertheless both cultures have profound potential applications in reducing the pollution of DMSW effluent prior to its disposal.

Determination of 17 beta-estradiol and its metabolites in sewage effluent by solid-phase extraction and gas chromatography/mass spectrometry.

Abstract: The paper describes a simple and quantitative method for monitoring non-conjugated 17 beta-estradiol (E2) and its metabolites estrone (E1) and estriol (E3) as environmental contaminants in municipal sewage effluents. Estrogens were preconcentrated and cleaned up by solid-phase extraction using a reversed-phase C18 cartridge. They were derivatized with pentafluoropropionic acid anhydride, and the products were analyzed by gas chromatography/mass spectrometry. Recoveries from spiked distilled water and sewage were better than 87% at fortification levels of 100 and 20 ng/L. For a 1 L sewage sample and a concentration factor of 5000, detection limits were 5 ng/L for E1 and E2 and 10 ng/L for E3. In a brief survey of Canadian wastewater, these estrogens were detected in many raw sewage and effluent samples at concentrations ranging from 6 to 109 ng/L for E1, from < 5 to 15 ng/L for E2, and from < 10 to 250 ng/L for E3.

Process and apparatus for electrocoagulative treatment of industrial waste water

Abstract: An electrocoagulation system for removing contaminants from waste effluents comprising an electrocoagulation reactor (140) having charged and uncharged plates and allowing serial flow of water therethrough. The reactor (140) is connected to a voltage source (160) to charge some of the plates positive and negative plates. The system allows waste water to enter the reactor (140) for coagulation therein, the waste water leaving the reactor (140) to enter a defoam tank (200) for agitation which allows trapped bubbles to rise to the surface of the tank (200) as foam. From the defoam tank (200), waste water goes through a sludge thickener, to allow sludge to settle at the bottom thereof and waste water is drawn off from the sludge thickener to flow to a clarifier (250). The pump removes sludge forming at the bottom of clarifier (250) to take it back to the sludge thickener. The sludge is drawn out the bottom of the sludge thickener for transport to a press (280) where most of the water is removed therefrom. Water is drawn off the top of the clarifier (250) for transport to a conventional sewer system, or for reuse.

Effects of sodium accumulation on soil physical properties under an effluent-irrigated plantation

Abstract: Effluent irrigation commonly results in increased soil sodicity, because of the medium-to-high salinity and high sodium concentrations of many effluents. The exchangeable sodium percentage (ESP) of soils at the Wagga Wagga Effluent Plantation Project increased from 25% at some depths within the surface 0·6 m of soil, after 5 seasons of irrigation with either (i) treated sewage effluent or (ii) bore water with similar salinity and sodium adsorption ratio (SAR). A survey of dispersion index (DI) and saturated hydraulic conductivity (Ksat) was carried out to investigate the effects of increased soil sodicity on soil physical properties. The Ksat was measured after 5 irrigation seasons at 2 depth intervals (0·15-0·45 m and 0·5-0·8 m) using both bore water and distilled water, and compared with measurements made at the same sites using bore water before irrigation commenced. Both DI and ESP were measured at each of 3 depths in the surface 0·6 m of soil. The DI in distilled water was positively correlated with ESP, with finer soil textures having higher DI for the same ESP. When measured in bore water or effluent, DI was very low and not related to ESP. Ksat was significantly lower after 5 irrigation seasons, and significantly lower in distilled water than in bore water. However, there was no relationship between Ksat and ESP. It was concluded that the increased ESP caused an increased tendency for soil dispersion but was not shown unequivocally to lead to decreased Ksat. The increased sodicity does not seem likely to affect continued use of the land for effluent irrigation, but may affect its suitability for alternative uses that involve physical disturbance of the soil, for example, by cultivation.

Effects of backwashing on biological filters

Abstract: The success of biological filtration depends on careful control and maintenance of the amount of biomass on the media during the maturation period and backwashing as well as during sudden changes in hydraulic loading. Various backwashing strategies and hydraulic transients were studied to determine how they affected filtration performance of biofilters in terms of effluent quality and head loss. Biological filters backwashed with a combination of air plus subfluidization water flow at collapse pulsing, followed by water wash with 25 percent bed expansion, can produce a water low in assimilable organic carbon (AOC). Compared with airscoured filters, water-washed filters produced lower initial peaks during ripening and similar effluent AOC. Chlorinated backwash affects biological activity. Under the conditions of these experiments, chlorinated backwash produced higher AOC and nonpurgeable organic carbon in the filter effluent. A sudden 30 percent increase in hydraulic loading had a greater effect on biological filtration performance than on conventional filtration, accelerating filter breakthrough and causing poorer effluent quality.