Showing papers on "Effluent published in 1984"

Complexation of heavy metals by extracellular polymers in the activated sludge process

Abstract: Raw industrial and domestic wastewaters are likely to contain persistent anthropogenic pollutants, one group of which, the heavy metals, is particularly hazardous. Therefore, these ma terials must be removed prior to effluent discharge to reduce the potentially harmful effects to both the ecosystem of the receiving watercourse and the public health.1 Englande and Reimers2 have stressed that adequate dilution capacity of receiving waters is important to minimize the adverse effects of effluents, especially in areas where water reuse is practiced. In the U.K., during the low flow period of 1976, 40% of the River Derwent consisted of effluent, mainly from industry3; in other areas with extensive water reuse, almost 90% of surface flow could be from wastewater effluents.4 Because of the nature of wastewater treatment processes, accumulation of mineral content is inherent in water reuse2; thus, considerable environ mental concern has focused on these nonbiodegradable and toxic heavy metals.5 By whatever method water quality control standards are used, the movement to reduce and ultimately eradicate aquatic pollution is likely to require increased restrictions on the discharge of metal-laden and other effluents.6 To comply with the standards, industrial effluents could be diverted from direct discharge to sewers, which could cause treatment plant perfor mance to deteriorate but which would improve the condition of receiving water. Thus, as standards are raised, wastewater treatment will contribute significantly to the maintenance of surface water quality. Particulate and precipitated material is removed by primary sedimentation, which generally accounts for up to 40% of the initial metal load.7'8 Forms of metal entering the biological treatment stage are predominantly soluble.9 Biological removal of soluble metals is critical because their overall retention depends on absorption by the activated sludge biomass.

Enhanced hydrogen recovery from effluent gas streams

Abstract: Effluent gas streams for steam reforming, partial oxidation or coal gasification operations are advantageously treated in shift conversion, scrubbing and pressure swing adsorption units for recovery of a purified, hydrogen-containing product gas stream. By recycling a portion of the waste gas removed from the pressure swing adsorption system to the shift conversion unit and/or to the effluent gas generation operation, enhanced product recovery is achieved without the necessity for employing low temperature shift or for achieving essentially complete removal of the carbon dioxide content of the gas being treated prior to its passage to said pressure swing adsorption system.

Use of artificial wetlands to remove nitrogen from wastewater

Abstract: As demands for water continue to increase and new water sources become scarcer and more expensive to develop, water resource planners look for alternative methods, such as waste water reclamation, to increase supplies. The Clean Water Act of 1977 (PL95-217) encourages the use of alternative and in novative technologies for water reuse. The concept of using wetlands for cost-effective and energy efficient treatment of municipal wastewaters has been dem onstrated both in Europe,1,2 and in the United States,3-6 with some degree of success; however, to date there has been little literature published on the operational parameters and associated treatment efficiency of wetlands (either natural or artificial) spe cifically designed for the removal of certain problem constituents, such as nitrogen. The deleterious effects of nitrogen on the aquatic environment include the increased eutrophication of receiving waters, and the increased risk of methemoglobinemia in human infants where elevated levels of nitrate (N03) or nitrite (N02) nitrogen are present in drinking supplies.7 With regard to the latter case, the Committee on Water Quality Criteria of the National Acad emy of Science has recommended that N03-nitrogen (NO3-N) concentration not exceed 10 mg/L in public water supplies.8 Therefore, it is essential that whenever reclaimed wastewater is injected or percolated into a domestic groundwater supply for recharge, a treatment process be selected that is capable of meet ing drinking water standards (<10 mg/L NO3-N). The most successful procedure for the removal of nitrogen from wastewater is sequential nitrification-denitrification, whereby ammonia (NH3) is first oxidized to NO3 by chemoau totrophic nitrifying bacteria, and then reduced to the gaseous end products (nitrogen gas, N2 or nitrous oxide, N20) by denitrifying bacteria, which utilize N03 or N02 as respiratory electron acceptors to carry out the oxidation of carbonaceous organic substrates. Denitrifying systems for NO3 removal from secondary wastewaters, agricultural drainage waters, or contam inated groundwater supplies, all of which contain very low levels of biochemical oxygen demand (BOD)?and often require sup plemental organic carbon (methanol) to increase the carbon pool and stimulate denitrification. Ehreth and Basifico9 pointed out the importance of low-cost alternatives to methanol, the use of which can account for nearly 50% of the operation and maintenance costs of treatment.10 Gersberg et al.,11 described the use of pilot-scale (66-m2) ar tificial wetlands as biological systems for the removal of N03 from secondary wastewater effluents. This report describes stud ies with larger, demonstration-scale (820-m2) artificial wetlands, which removed nitrogen from secondary wastewater effluents. Methanol, or lower-cost alternatives such as mulched plant bio mass or blended primary effluent, were used as the carbon sources to drive the denitrification process.

Biofilm Fouling of RO Membranes—Its Nature and Effect on Treatment of Water for Reuse

Abstract: Increasing demand for domestic water has spurred renewed activity in the treatment of secondary municipal effluent to augment existing resources. Demineralization of pretreated wastewater by reverse osmosis yields safe, potable supplies, but microorganisms and chemical substances in the feedwater rapidly impede membrane flux, reducing plant efficiency and increasing treatment costs. The nature of biofilm development was studied at an advanced wastewater treatment plant in Southern California under low- and high-chlorine conditions, where close relationships were found between the accumulation of biochemical material and the loss of membrane premeability. High chlorine residuals damaged the membrane structure and reduced mineral rejection capacity. The demand for potable water continues to increase in Southern California, renewing interest in wastewater reclamation to bolster existing domestic water supplies. Forecasts for the next five to ten years estimate a continuing, rapid rise in demand for domestic water. Industry professionals are concerned about this increasing need and are taking steps to prevent shortfalls.

Tri and tetra-chloroveratrole, metabolites produced by bacterial O-methylation of tri- and tetra-chloroguaiacol: an assessment of their bioconcentration potential and their effects on fish reproduction

Abstract: We have demonstrated that strains of bacteria belonging to the genera Pseudomonas and Acinetobacter possessed the ability to transform, by O-methylation, components of spent bleachery effluent such as 4,5,6-trichloroguaiacol and high molecular weight chlorinated lignin. O-Methylation could be enhanced by the presence of a cosubstrate such as succinate or 4-hydroxybenzoate. We have used zebra fish (Brachydanio rerio) to examine bioconcentration potential, toxicity to embryos and larvae, and the sensitivity of the offspring of exposed adults. Bioconcentration factors (total wet weight) on a logarithmic scale were 3.5 and 4.4 for 3,4,5-trichloroveratrole and tetrachloroveratrole, respectively. The potential for bioconcentration of the other neutral metabolites was inferred from estimated values of the octanol–water partition coefficients. 3,4,5-Trichloroveratrole, tetrachloroveratrole, pentachloroanisole, and 1,2,3-trichloro-4,5,6-trimethoxybenzene had threshold toxic concentrations to zebra fish embryos and...

Biological Treatment of Cyanidation Waste Waters

Abstract: An attached growth aerobic biological treatment process has been developed at Homestake Mining Co.’s Lead operation which not only oxidizes free and complexed cyanides, including the stable iron complexed cyanides, but also thiocyanate, and the oxidation byproduct ammonia. Through the employment of a mutant strain of bacteria which has been gradually and specifically acclimated to the waste, these potential pollutants are mineralized to relatively harmless sulfates, carbonates, and nitrates. The resultant effluent, through toxicological testing, has been shown compatible with the receiving stream, which serves as a cold water marginal trout fishery.

An evaluation of single- and separated-phase anaerobic industrial wastewater treatment in fluidized bed reactors.

Abstract: Four fluidized bed reactors were used to evaluate single-and separated-phase anaerobic treatments of a high strength wastewater. Two reactors were fed with a synthetic wastewater, containing glucose as the primary carbon source, with a COD of 1.2 x 10(4) mg/L while the remaining pair were fed with a wastewater with a COD of 6000 mg/L. AT each influent strength, one fluidized bed reactor was operated as a single-phase system while the other was operated as a methanogenic reactor which was preceded by an acidification reactor in a separatedphase system. The reactors were operated under steady-state and variable process conditions. The separated-phase system consistently gave a better quality effluent with lower effluent suspended solids and total COD, and the methane yield was also improved. Under variable process conditions, the separated-phase system was inherently more stable and recovered more rapidly following a shock loading. Propionate and acetate degradation studies indicated that the biomass in the methanogenic fluidized beds of the two-phase systems was more adapted to volatile acid degradation than the biomass in the single-phase fluidized beds.

Comparison of microporous filters for concentration of viruses from wastewater.

Abstract: The 1-MDS Virosorb filter and the 50S and 30S Zeta-plus filters, all with a net positive charge, were compared with the negatively charged Filterite filter for concentration of naturally occurring coliphages and animal viruses from sewage effluent. When Filterite filters were used, the effluent was adjusted to pH 3.5 and AlCl3 was added before filtration to facilitate virus adsorption. No adjustment was required with the positively charged filters. Sets of each filter type were eluted with 3% beef extract (pH 9.5) or eluted with 0.05 M glycine (pH 11.5). A maximum volume of 19 liters could be passed through 142-mm diameter Filterite filters before clogging, whereas only 11, 11, and 15 liters could be passed through the 1-MDS, 50S, and 30S filters, respectively. For equal volumes passed through the filters, coliphage recoveries were 14, 15, 18, and 37% in primary effluent and 40, 97, 50, and 46% in secondary effluent for the Filterite , 1-MDS, 50S, and 30S filters, respectively. No statistically significant difference was observed in the recovery of animal viruses among the filters from secondary effluent, whereas in the Filterite and 50S filters, higher numbers of viruses from primary effluent were recovered than in the 1-MDS and 30S filters in two of three collections. Glycine was found to be a less-efficient eluent than beef extract in the recovery of naturally occurring viruses.

Effect of low dissolved oxygen concentration on effluent turbidity

Abstract: An activated sludge plant in Atlanta, Ga. (R. M. Clayton Plant) with a design treatment capacity of 5.2 m3/s (120 mgd) was operated for 9 months with average dissolved oxygen (DO) concentrations of less than 1 mg/L in the aeration basins as a result of aeration equipment failure. During this period, plant effluent was turbid regardless of changes in sludge age, aeration basin contacting pattern (conventional versus use of aeration and reaeration basins), amount of solids recycled from sludge handling facilities, and seasonal variations. Industrial wastes did not seem to be the cause of high effluent turbidity. The only operating parameter that was consistent throughout this period was low DO concentration. Once the aeration equipment was repaired and the DO concentration increased to more than 2 or 3 mg/L, plant effluent cleared markedly within a few days. Concurrently, effluent suspended solids concentration which had typically been 40 to 60 mg/L, was reduced to 15 to 30 mg/L. Further verification that effluent turbidity was related to DO concentration occurred when a deterioration followed by im provement in plant effluent corresponded with failure and repair of the aeration system. Others involved in the operation of activated sludge plants12 have observed the same phenomenon. However, little reference to this phenomenon could be found in the literature. The purpose of this research was to demonstrate this relationship and to identify responsible mechanism(s).

Papillomas on Fish Exposed to Chlorinated Wastewater Effluent

Abstract: The presence of carcinogenic and mutagenic chemical(s) in the effluent of a wastewater treatment plant was indicated by papillomas developing on caged black bullheads (Ictalurus melas), hepatic enzyme induction in exposed fish, and Ames test mutagenicity of organic extracts of the wastewater. Although virus-like particles have been reported in papillomas of several other fish species, no evidence was obtained for the presence of viruses in the black bullhead papillomas. Mutagenic and carcinogenic chemicals were not identified in the wastewater, but chlorination was implicated as a factor contributing to the induction of the papillomas. The prevalence of papillomas on wild black bullheads exposed to the effluent decreased from 73 to 23% after the amount of residual chlorine (CAS: 7782-50-5) in the effluent leaving the chlorine contact chamber was reduced from 1.3-3.1 mg/liter to 0.25-1.2 mg/liter.

Subsurface Drainage Water Quality from Land Application of Swine Lagoon Effluent

Abstract: WATER quality was monitored for subsurface drainage from small plots receiving 325, 650 and 1300 kg N/ha/yr from sprinkler-irrigated swine-lagoon effluent. Subsurface flow volumes and nutrient concentrations are reported for 20 months at the end of a 6-yr treatment period. Nutrient mass balances for nitrogen and phosphorus which include uptake by Coastal bermudagrass, soil accumulation, surface runoff, subsurface drainage and an estimate of nutrients leaching below the root zone are reported.

Use of Peat for On-Site Wastewater Treatment: I. Laboratory Evaluation

Abstract: Peat has been found to be an effective medium for the treatment of municipal and industrial wastewaters. Recent research has indicated that a peat filter can be utilized in the treatment of septic tank effluent (STE). Laboratory columns were used to determine the treatment capacity of sphagnum (Sphagnum spp.) peat at varying hydraulic and organic loadings. Thirty centimeters of peat compacted to a density of 0.12 Mg/m³ was found sufficient to treat STE at a hydraulic loading of 8.1 cm/d and an organic loading of 20.2 kg BOD₅/1000 m² per day (BOD₅ = 5-day biochemical oxygen demand). The BOD reduction exceeded 95% and suspended solids 90%. Chemical oxygen demand (COD) reduction was only 80% as the effluent COD exceeded 100 mg/L. The relatively high COD was attributed to the organic matter leached from the peat itself. This was reflected in a light yellow color and lowered pH in the effluent. The effect seemed to be temporary in nature and improved COD, color, and pH values were obtained with time. Excellent fecal coliform reduction was obtained, suggesting that a separate disinfection operation may not be necessary. Nutrient removal under aerobic conditions revealed < 10% P and N removal; however, nitrification was nearly complete. Significant denitrification was promoted under anaerobic conditions and a 62% reduction in total N was observed. Specifications for a full-scale filter include a hydraulic loading of 4.1 cm/d for a typical strength STE (10 kg BOD₅/1000 m² per day) as 8.1 cm/d proved to be excessive at low temperature (5°C). The filter should have a minimum of 30 cm of lightly compacted peat (0.10–0.12 Mg/m³) below the distribution pipes. These recommended design criteria result in a much smaller filter than previously tested.

Water for the Dyehouse: Supply, Consumption, Recovery and Disposal

Abstract: Factors which account for the almost universal choice of water as a medium for textile dyeing processes are outlined. Many of the dominant trends in the development of improved equipment and processes during the last decade have been associated with the control and treatment of this essential resource. Typical examples include the strong links between water conservation and most of the effective ways of saving energy, improvements in effluent treatment plants to minimise the impact of water-borne contaminants on the environment, exploitation of the possibilities for reuse of process water or treated effluent in further processing, as well as the direct objective of holding in check the rising contribution of water supply and effluent treatment to limit overall costs. This broad expanse of water, pure and impure, is surveyed from the viewpoint of the textile dye user, since, by virtue of the physical and chemical properties of textile dyes, he is also invariably a continual user of water.

Production of fructose syrup

Abstract: Novel, highly useful, sweet fructose-containing syrups also containing fructooligosaccharides are provided herein by the partial or substantially complete hydrolysis of inulin. The process includes first providing an aqueous solution containing inulin from Jerusalem artichoke tubers or chicory roots. Then the warm aqueous solution of inulin is passed through a column containing a strong acid cation-exchange resin, thereby providing an effluent having a pH of about 2.0-about 3.0. The effluent is then hydrolyzed by heating at a temperature of about 70°-about 100° C., and the hydrolyzate is passed through a column containing of about 6.5-about 7.0. resin, thereby providing an effluent having a pH about 6.5-about 7.0. Optionally, after the hydrolysis step, the hydrolyzate is decolorized by contact with activated or granular charcoal. The effluent is then concentrated to a syrup containing less water than the effluent, e.g. one containing about 40-about 70% solids. The sweet fructose syrup containing oligofructans can be used as truly "health" sweetener, particularly ideal for elderly people and diabetics. The pulp obtained after the juice extraction is rich in protein and can be used as feed.

Stratigraphic Evidence of Eutrophication in an Estuary

Abstract: Vertical changes in chlorophyll degradation products preserved in sediments deposited in an urban estuary show a significant increase in algal productivity with the introduction of sewage effluent into the river. By comparison, algal production during intensive agriculture of the watershed, including heavy applications of fertilizers, was less by an order of magnitude where there was no sewage discharge from a point source. Concentrations of orthophosphorus correspond with concentrations of algal cells and chlorophyll in the water column and are greater by an order of magnitude where sewage is discharged into an estuary draining an urban-agricultural watershed than where there is no sewage. The response of the estuary to short- and long-term changes in the amount of sewage discharged is reflected by similar changes in chlorophyll production. However, chlorophyll production does not correspond with increases in the amount of fertilizers used in recent years over the amount used in the middle to late nineteenth century.

Removal of cadmium from wastewaters

Abstract: There has been increasing concern over the discharge of heavy metals into the environment as evidenced by actions taken by pollution regulating agencies in various industrialized nations to impose severe discharge limits for certain heavy metals. This paper describes the source and quantity of cadmium in waste waters. The effluent limitation of cadmium is presented, followed by discussions of various treatment methods including chemical precipitation and flotation, ion exchange, adsorption osmosis as well as other effluent polishing techniques applied to both industrial discharges and municipal waste waters. Finally, several methods of cadmium recovery from industrial discharges are discussed.

Penetration of different human pathogenic viruses into sand columns percolated with distilled water, groundwater, or wastewater.

Abstract: The adsorption of several enteroviruses and rotavirus SA11 to sand from an aquifer in the Federal Republic of Germany was estimated in sand-filled columns loaded with ca. 10(7) PFU and run at a velocity of 2.5 m/day for 12 h. After either distilled water, groundwater, secondary effluent, or tertiary effluent was percolated, the sand core was slowly extruded out of the column and cut in 1-cm slices. The slices were eluted with nutrient broth, and the amount of viruses in the broth was estimated. The best adsorption was promoted by groundwater and tertiary effluent, followed by distilled water and secondary effluent. Similar experiments, carried out at different percolation rates, indicated that a 50-day underground stay of recharged water probably suffices to eliminate viruses in the groundwater-recharged tertiary effluent. However, when viruses and sand were incubated in the presence of the surfactants sodium dodecyl sulfate, nonyl phenol, dodigen 226, or alkylbenzylsulfonate, the adsorption of the viruses was substantially diminished. Experiments in the presence of nonyl phenol seem to indicate that hydrophobic interactions are involved in the adsorption of viruses to sand.

Olefin fractionation and catalytic conversion system

Abstract: An improved catalytic process for converting an olefinic feedstock comprising ethylene and C3 + olefins to heavier liquid hydrocarbon product comprising the steps of: (a) prefractionating the olefinic feedstock to obtain a gaseous stream rich in ethylene and a liquid stream containing C3 + olefin; (b) vaporizing and contacting the liquid stream from the prefractionating step with hydrocarbon conversion oligomerization catalyst in at least one exothermic catalytic reaction zone at elevated temperature and pressure to provide a heavier hydrocarbon effluent stream comprising heavy, intermediate and light hydrocarbons; (c) flashing the effluent stream between the reaction zone and a first phase separation zone by reducing pressure of the effluent stream, thereby producing a first liquid effluent fraction rich in heavy hydrocarbons and a first effluent vapor stream containing intermediate and light hydrocarbons; (d) condensing a portion of the first effluent vapor stream in a second phase separation zone to produce a second liquid effluent stream rich in intermediate boiling range hydrocarbons and a second vapor stream rich in light hydrocarbons; (e) recycling at least a portion of the second liquid effluent stream as a liquid sorbent stream to prefractionating step (a); (f) further reacting the recycled gasoline together with sorbed C3 + olefin in the catalytic reactor system of step (b).

Removal of dissolved heavy metals from aqueous waste effluents

Abstract: The invention relates to an environmentally-compatible process for the batchwise or continuous removal of toxic heavy metals from an aqueous effluent such as power plant wastewater. It includes the steps of activation, treating and separation. In the first step, iron in particulate form is contacted with an oxygen-containing gas such as air and an aqueous medium such as the wastewater itself under conditions providing an oxygen-water-iron interface for a period sufficient to react at least a substantial portion of the exposed iron surfaces with the oxygen and water so as to produce active surfaces on the iron particles having enhanced adsorption for the heavy metals. In the second step, without allowing the active adsorptive surfaces to dry, the particles are inundated with the aqueous effluent so as to bring about intimate contact of the aqueous effluent and adsorptive surfaces to effect adsorption of at least a substantial portion of the heavy metals on to the adsorptive surfaces. In the third step, the contacted aqueous effluent having reduced amounts of heavy metal is separated from the iron particles having heavy metals adsorbed thereon. These iron particles may then be charged to an iron or steelmaking process.

Irrigation of Monterey Pine with Wastewater: Effect on Soil Chemistry and Groundwater Composition

Abstract: Fifteen-year old Monterey pine (Pinus radiata) was irrigated for 3 yr with wastewater derived from industrial and municipal sources. The wastewater contained high concentrations of Na²⁺ and HCO₃⁻ and was quite alkaline. Irrigation thus caused substantial increases in exchangeable Na²⁺, extractable P, exchangeable K⁺, pH, and the electrical conductivity of the soil solution. Highly colored organic compounds derived from pulp-mill effluent apparently combined with inorganic N from municipal effluent to form organic N compounds. Nitrogen remained largely in the organic form and became concentrated in the groundwater with colored humic compounds. The greatest environmental hazard in the use of such blended wastewater for irrigation is the contamination of drainage water with colored, saline water containing high concentrations of organic N. The organic compounds appeared to inhibit nitrification in the groundwater.

Isolation and selection of phenol - degrading microorganisms from an industrial effluent

Abstract: Among 12 bacterial and fungal isolates from a phenol-containing effluent, an Acinetobacter sp. and a Fusarium flocciferum strain could be adapted to growth on up to lg/1 of phenol.