Showing papers on "Wastewater published in 1981"

Wastewater Engineering: Collection and Pumping of Wastewater

Abstract: Wastewater engineering: collection and pumping of wastewater , Wastewater engineering: collection and pumping of wastewater , کتابخانه مرکزی دانشگاه علوم پزشکی تهران

Method for treating wastewater using microorganisms and vascular aquatic plants

Abstract: A method for treating wastewater comprising the steps of subjecting the wastewater to an anaerobic settling step for at least 6 hours and passing the liquid effluent from the anaerobic settling step through a filter cell in an upflow manner, wherein the effluent is subjected first to the action of anaerobic and facultative microorganisms and then to the action of aerobic microorganisms and the roots of at least one vascular aquatic plant.

Municipal wastewater treatment with the anaerobic attached microbial film expanded bed process

Abstract: Studies indicating that a new biological energy-producing wastewater treatment process would produce little or no excess sludge can be used for domestic wastewater treatment are summarized. These studies, ongoing at Cornell Univ. since 1974, have involved the continuous operation of several slightly different laboratory models of an anaerobic attached film expanded bed (AAFEB) reactor to treat primary settled wastewaters, and numerous shock loading investigations. Test conditions and results for the AAFEB treatability and shock loading studies are outlined. Results indicate that the AAFEB process is an effective means of wastewater treatment that produces a minimal amount of biological sludge while simultaneously producing energy in the form of methane gas. (2 diagrams, 7 graphs, 28 references, 3 tables)

Anaerobic activated carbon filter for the treatment of phenol-bearing wastewater

Abstract: An experiment using an activated carbon filter for the treatment of phenol-bearing wasterwater from coal gasification processes is discussed. Two granular-activated-carbon-packed anaerobic filter systems were constructed for use in the study. Both phenol and glucose of phenol-fed reactor systems were operated under continuous feeding for a period of 735 days. The glucose-fed reactor was very effective in reducing the organic content of the feed substrate. The performance of the phenol-fed reactor was tested at three different phenol concentration levels: (1) 200 mg/l; (2) 400 mg/l; and (3) 1000 mg/l. Using the 200 mg/l concentration of phenol an average 79% of the feed chemical oxygen demand (COD) was accounted for in the aqueous and gaseous phases of the final effluent. Using 400 mg/l the COD accounted for the aqueous and gaseous phases of the effluent rose to an average of 92%, and using 1000 mg/l, the COD removal efficiencies from the three columns fell to an average of 90%, respectively. Despite the differences in removal efficiencies between the different phases of the experiment, the granular-activated-carbon-packed anaerobic bioreactor proved to be an effective process in the reduction of phenol from a synthetically prepared wastewater. In addition to phenol reduction, there was alsomore » a consistent and effective reduction of the chemical oxygen demand and the total organic carbon content of the waste at a time when a methane-rich gaseous by-product was being produced simultaneously.« less

Treatment of industrial wastewaters

Abstract: An industrial wastewater treatment method is described whereby heavy metals dissolved in the wastewater are precipitated as a slurry which, when allowed to settle, will form a sludge containing at least 10 weight percent solids In the method, an aqueous suspension or solution of a neutralizing agent is introduced into a first reactor A suspension containing particles of carrier agent is also introduced into the first reactor A portion, if not all, of the neutralizing agent is adsorbed on the surface of the particles of the carrier, which are maintained in suspension in the first reactor The carrier, with its adsorbed neutralizing agent, is passed to a second reactor and simultaneously the contaminated industrial wastewater is added to the second reactor The pH of the wastewater is adjusted to a range between 84 and 106 by the neutralizing agent Within such pH range, a substantial portion, if not all, of the heavy metals are precipitated in the form of a slurry The mixture in the second reactor is passed to a solids separation device The solids in the slurry settle to the bottom of the device to form a sludge which is removed therefrom Purified water is removed as an overflow from the separation device Optionally, a flocculant may be added to aid in settling the solids Insoluble calcium salts may also be precipitated in the second reactor Such insoluble salts are adsorbed on the surface of the carrier and/or the heavy metal slurry particles and become part of the sludge formed in the separation device

Industrial waste carbon sources for biological denitrification

Abstract: Biological denitrification is one of the most economical and effective means of nitrate reduction, and methanol appears to be the most popular electron donor. Although methanol has certain advantages over industrial or municipal wastewater carbon sources, its significant disadvantage is cost. This alone justifies consideration of alternative electron donors. As part of an extensive nitrogen removal program conducted at the Wastewater Technology Centre, Burlington, Ontario, a project was initiated to identify and evaluate industrial wastes or waste by-products which could be used as replacements for methanol. Forty-one waste samples were collected and chemically analyzed to determine their organic carbon and nitrogen concentrations. Bench scale testing followed with the determination of batch denitrification rates for 30 of the characterized wastewaters. Twenty-seven of the 30 wastes exhibited denitrification rates equal to or greater than those observed using methanol. A distillery fusel oil exhibited the highest rate of 0.331 mg NO T -N·mg MLVSS –1 ·d –1 as opposed to the mean rate, using methanol, of 0.097 mg NO T -p-N·mg MLVSS –1 ·d –1 . Many of the wastes exhibited substrate consumption ratios equal to or less than that for methanol. Data analyses showed a correlation between the initial FOC:N ratio and substrate consumption ratio. Cost analysis indicated that many industrial wastewaters are economically more attractive than methanol as an external carbon source for denitrification.

Nitrification treatment of wastewater

Abstract: In a two stage activated sludge plant, where in the first stage the major proportion of the organic pollutants is decomposed and in the second stage the decomposition of the residual organic pollutants is conducted in conjunction with nitrification, the nitrifying bacteria are fixed on a low-density, macroporous carrier, e.g., particulate, polyurethane, optionally with activated carbon as well. The second stage can be operated as a mixed activated sludge tank or a biological filter, and in either case, it is possible to avoid a post clarification stage.

Use of Aquatic Macrophytes for Wastewater Treatment

Abstract: Wastewater treatment systems using water hyacinths have the capability of producing secondary or advanced secondary effluents. Hyacinths also have the potential for producing effluents meeting advanced waste treatment standards if optimum plant harvesting techniques and supplemental methods for additional phosphorous removal are developed. Widespread use of hyacinth systems will be confined to relatively warm climates because growth ceases at water temperatures below 50°F (10°C). Treatment facilities using duckweed could be used in colder climates, however, systems using this plant are in a very preliminary stage of development. In addition to the removal of conventional pollutants, aquatic macrophytes systems also have the capability of biologically concentrating heavy metals and synthetic organic chemicals. Preliminary cost analyses indicate water hyacinth systems could be more economical than comparable land or conventional treatment techniques.

Electrolytic reactor for cleaning wastewater

Abstract: Wastewater from metal plating operations is treated to remove heavy metal and other contaminants, including toxic organic materials, chelating agents, and cyanide. The wastewater is passed through the cathode and anode of an electrochemical reactor in which the cathode preferably comprises a felt mass of conductive fibers and the anode comprises porous carbon, carbon fibers or metal oxides. A method and apparatus are disclosed which are particularly useful in removing impurities from plating plant wastewater.

Evaluation of acid-fast bacteria, candida albicans, enteric viruses and conventional indicators for monitoring wastewater reclamation systems

Abstract: The removal of micro-organisms in a 4 000 m3/d modified experimental wastewater reclamation plant, in which high lime treatment was replaced by ferric chloride clarification, and intermediate chlorination by ozonation, was studied. The two new unit processes contributed satisfactorily to the reduction in numbers of microorganisms. Enteric viruses were removed effectively after clarification and none were detected in more than 11 000 l of reclaimed water analysed by means of ultrafiltration, which has a high recovery efficiency. The absence of coliphages proved a reliable indication of the removal or inactivation of enteric viruses. Acid-fast bacteria were exceptionally resistant to most of the treatment processes and their absence after chlorination stages ensured the inactivation of vegetative bacteria and viruses. Pseudomonas aeruginosa was relatively resistant and especially useful for the evaluation of ozonation. Total coliforms were rather sensitive but have the advantage that the identification of isolates may establish faecal pollution. Candida albicans was removed after clarification and displayed no indicator value. The total plate count was the most sensitive indicator of general plant performance. The results show that a total plate count of less than 100 per 1 ml and the absence of acid-fast bacteria, P. aeruginosa, total coliforms and coliphages from 100 ml of the final water, and preferably two intermediate stages, is a feasible limit with a wide safety margin for routine monitoring of established wastewater reclamation systems. Data on the survival of microorganisms in individual unit processes prove that these indicator organisms eliminate the need for enteric virus tests.

Treatment of coal coking and coal gasification wastewaters

Abstract: Studies were conducted with heavily contaminated effluents from coal coking operations and coal gasification processes to obtain basic engineering and design data for biological waste treatment. Specific objectives were to: determine the influence of wastewater compositional characteristics on pretreatment/ identify minimum dilution requirements/ evaluate biological treatment of effluents receiving different types of pretreatment: determine biological oxidation growth constants for treatment of effluents/ determine removal efficiencies for primary effluent contaminants/ and investigate parameters that effect biological oxidation of cyanide and thiocynate. Experimental results are presented.

Effect of mean-cell residence time on organic composition of activated sludge effluents

Abstract: Wastewater effluents from activated sludge treat ment processes contain complex organic compounds that frequently must be removed in tertiary treatment systems. The physical and chemical characteristics of these organic compounds affect both the selection and performance of subsequent treatment processes and the ultimate environmental impact of the discharge of treated wastewaters. In this regard, the mean cell res idence time, 0C, of an activated sludge suspension, in conjunction with other suspension characteristics, es tablishes an average value for the minimum doubling time required for retention of specific microorganisms within an activated sludge system. Microorganisms growing at rates slower than that dictated by dc are washed out of the process. Therefore, if a specific mi croorganism or consortium of microorganisms is re quired for the degradation of specific organic com pounds, the value of 6C will significantly affect effluent organic quality. The influences of organism washout and resulting changes in microbial populations were examined through an investigation of physical and chemical characteristics of activated sludge suspensions and effluents to determine quantitatively the effect of 6C on the organic quality of activated sludge effluents.

Isolation of viruses from drinking water at the Pont-Viau water treatment plant.

Abstract: Viruses were isolated from every sample of raw (100 L) and treated (1000 L) water collected at a water treatment plant drawing sewage-contaminated river water. Few plaque-forming isolates were found but cytopathogenic viruses were isolated as frequently in drinking water as in raw water. In drinking water some samples contained more than 1 cytopathogenic unit per litre, but most contained 1–10/100 L. These viruses had not been inactivated or removed by prechlorination, flocculation, filtration, ozonation, and postchlorination. There were no coliforms present and a residual chlorine level had been maintained. Poliovirus type 1 was a frequent isolate but many isolates were nonpoliovirus. The presence of these viruses in drinking water raises questions about the efficacy of some water treatment processes to remove viruses from polluted water.

Waste water purification

Abstract: A novel process for the purification of waste water and/or waste water sludge comprising subjecting the waste water and/or waste water sludge to first a methane fermentation step, then a denitrification step and finally an oxidation step by aeration, the electron donor in the denitrification step being mainly the sulfide from the methane fermentation step and the remaining reduced compounds in the liquid effluent from the methane fermentation step being oxidized in the aeration step.

Wastewater treatment process

Abstract: Wastewater (10) is continuously disinfected in a mixing zone (14) by combining the wastewater (10) with sufficient SO2 (12), and optionally with acid (8), that the wastewater has a selected free SO2 content of at least 5 mg/liter The combined SO2/wastewater is maintained in a treatment zone (24) at the selected free SO2 content for at least about 5 minutes The wastewater can be treated by dissolving SO2 into a first portion (58) of the wastewater and combining the first portion with SO2 dissolved therein with a second portion (64) of the wastewater stream in the treatment zone (24) SO2 can be stripped in a stripping zone (110) from the wastewater, and the stripped SO2 (114) can be recycled

Electromagnetic ground water conditioning system and sampling device for waste water and fermentation makeup water

Abstract: An electromagnetic ground water conditioning system and sampling device comprising a holding tank, a pump, filters and timers to regulate the time and duration of blowout of settled solids at the bottom of the tank. The electromagnetic water conditioning unit is that disclosed and claimed in my allowed patent application Ser. No. 153,219 filed May 27, 1980, entitled Free Flow Non-Corrosive Water Treatment Device, now U.S. Pat. No. 4,288,323. A blowout valve at the bottom of the tank is solenoid operated and regulated to discharge a small liquid volume of settled solids. One timer is a 24-hour timer to set the blowdown start, the other is a 30-minute timer which sets the duration of the blowdown. For ground water or sewage water or industrial waste water a 2-hour setting on the 24-hour timer and a 10-second setting on the 60-second timer is preferred. The amount blown out is 1/10 gallon. This assembly and system is especially useful for sampling and monitoring industrial waste water, or industrial effluent, for preparing makeup water for fermentation and non-chemical sterilization and for the treatment of ground water containing toxic heavy metals in solution by hydrogen sulfide alone.

Non-biological elimination mechanisms in a biological sewage treatment plant

Abstract: Non-biodegradable volatile organic pollutants may be efficiently eliminated from waste water in an activated sludge process either by absorption into the biomass of the sludge or by volatilization concomitant with the oxygen transfer to the mixed liquor. The extent of absorption into the sludge solids is given by a distribution equilibrium between the solids and the liquid and can be predicted from the lipophility of the substances as measured by their n-octanol-water distribution coefficient. The volatilization of less lipophilic substances can be interrelated to the mass transfer coefficient of oxygen and can be predicted from the critical volume of these substances. The validity of these non-biological elimination mechanisms was checked in two semi-technical activated sludge processes operated in parallel by establishing a mass balance for four selected indicator compounds indigenously present in municipal sewage. Volatilization and absorption into biomass are also of importance in predicting the fate and residence time of refractory organic substances in natural waters.

Method for the anaerobic degradation of organic material

Abstract: A system for the anaerobic bacterial degradation of organic material in waste water, comprising introducing the waste water into a contact reactor, pumping the Waste water into the bottom of a fluidised bed reactor containing anaerobic bacteria attached to the particles in the bed, the fluidised bed reactor having an effective volume not more than 0.35 times the effective volume of the contact reactor, returning the waste water which has passed through the fluidised bed reactor to the contact reactor and continuously or discontinuously removing treated effluent from the system. A start-up procedure for the anaerobic treatment system is described comprising culturing anoxic bacteria in the system by adding nitrate ions to the waste water and gradually reducing the amount of nitrate ions in the stream until the population of anoxic bacteria is substantially replaced by a population of anaerobic bacteria. A viable microbial population is established in both the fluidised bed reator and the contact reactor.

Efficiency of ultrafiltration for the isolation of enteric viruses and coliphages from large volumes of water in studies on wastewater reclamation

Abstract: The efficiency of a pressure ultrafiltration procedure using flat membranes for the recovery of viruses from water was evaluated. The average recovery efficiency of Escherichia coli K12 Hfr phages from 1 l samples of activated sludge effluent was 69 %, and from 10 l samples of the effluent after primary clarification in a wastewater reclamation plant 72 %, after secondary clarification 83 %, and after sand filtration 91 %. Polio 1, 2 and 3 viruses, reovirus, a rotavirus and seven different morphological types of coliphages were recovered from seeded 100 l samples of distilled, tap or reclaimed water at an average efficiency of 94 %. Apart from the high recovery efficiency, ultrafiltration has advantages over other concentration techniques in that no chemicals have to be added to water samples, viruses are not exposed to pH extremes, no secondary concentration step is required, standard equipment is available, and the method is relatively economical and simple. The filtration rate was slow but may be improved by further research. Evidence is presented that the isolation of enteric viruses by means of ultrafiltration and the detection of isolates by means of TCID50 methods using primary vervet kidney cells, is a sensitive technique for the analysis of 100 l samples of conventionally treated or directly reclaimed drinking-water.

Positively charged filters for virus recovery from wastewater treatment plant effluents.

Abstract: Positively charged Zeta Plus filters were used to concentrate enteroviruses from 19 liters of effluent from activated sludge units. Neither the addition of salts nor the acidification of the effluent was required for adsorption of viruses to the filters. Viruses adsorbed to the filters were eluted by treating the filters with a solution of 4 M urea buffered at pH 9 with 0.05 M lysine. Eluted viruses were concentrated into final volumes of 1 to 2 ml by using a two-step concentration procedure that employed inorganic and organic flocculation. Approximately 50% of the viruses added to effluents could be recovered in the final sample. The procedure was used to monitor effluents from activated sludge units at two wastewater treatment plants for the presence of enteroviruses.