Showing papers on "Wastewater published in 1978"

of wastewater treatment

Abstract: The invention relates to a wastewater treatment process. In one embodiment, introducing raw sewage in a biological contactor 22 having a series of discs 24 mounted on a common shaft 25. To the wastewater stream an adsorbent capable of adsorbing impurities from the liquid. This adsorbent is, for example activated carbon is added at 26. The addition of this adsorbent improves the operating characteristics of the biological contactor and the solids were removed accumulated on the contactor at a rate equivalent to the rate at which these solids accumulate.

Influence of particle size on sludge dewaterability

Abstract: One of the primary objectives of wastewater treatment is the removal of solids. Once re moved, the resultant sludge must be treated and disposed of in some innocuous manner. Sludge handling systems commonly used rep resent a large and important cost center of wastewater treatment because its associated capital and operating costs may be as high as one-fourth to one-half of the total cost of wastewater treatment.1 In many wastewater treatment facilities, the bottleneck of the sludge handling system is the dewatering operation; it is also the least-under stood sludge handling operation, as evidenced by the numerous anomalies that exist in the literature. Although many factors are known to influence the dewatering characteristics of sludge, no clear understanding of their relative importance can be garnered from the literature. Through the research reported herein, an at tempt was made to properly evaluate these factors and place them in perspective.

Organic compounds in an industrial Wastewater: a case study of their environmental impact

Abstract: The wastewater and receiving waters and sediments from a specialty chemicals manufacturing plant are extensively analyzed for organic compounds. The concentrations of anthropogenic compounds range up to about 15 ppM in the wastewater and 0.2 ppM in the river (receiving) water, but up to several hundred ppM in the sediments. The composition of the river water reflects the composition of the wastewater except that some of the compounds appear to degrade or volatilize in the river. Many compounds accumulate in the sediments where they appear to be stable and build up to high concentrations. Some of the compounds are modified in situ. Various phenols are easily oxidized to quinones; these may be partially reduced back to phenols depending on the redox nature of the environment. Several compounds of known biological activity (herbicides, bacteriostats, and disinfectants) as well as some potentially toxic chemicals such as dichlorodibenzodioxin are present in the water. The long-term, low-level exposure to this wide variety of chemicals may have contributed to the lack of biota in this part of the river.

The distribution of heavy metals in anaerobic digestion

Abstract: In recent years, there has been a great deal of interest in the distribution and effects of influent wastewater heavy metals in conven tional wastewater treatment. Of the various process components of conventional waste water treatment, anaerobic digestion appears to be particularly vulnerable to excessively high heavy metals loadings to the treatment plant. The widespread use of anaerobic di gestion in the treatment of wastewater sludges has underscored the importance of under standing the various control problems caused by high heavy metal concentrations in treat ment plant sludges fed to anaerobic digesters. This study was undertaken to observe the ef fects of heavy metals on bench-scale anaerobic digesters and to determine the distribution of these metals among various forms in the digester.

Role of lime treatment in the removal of bacteria, enteric viruses, and coliphages in a wastewater reclamation plant.

Abstract: Lime flocculation/sedimentation in the first process unit of a 4,500-m3/day wastewater reclamation plant reduced numbers of microorganisms extensively when operated at pH 11.2. The efficiency was much less at lower pH values, and some bacteria even multiplied at pH 9.6. Data on reduction in the number of microorganisms in the lime treatment and subsequent units indicate that inactivation by hydroxide alkalinity plays an important role in the efficiency of lime treatment. Reductions in the numbers of enteric viruses were higher than those of coliphages, enterococci, and total plate and coliform bacteria, which indicate that lime treatment can be monitored by means of coliphage and conventional bacteriological tests. This paper illustrates the valuable role of high-pH lime treatment in reducing the load of pathogenic microorganisms on subsequent units, including ultimate disinfection processes, which is important in the multiple safety barrier concept of wastewater reclamation processes.

Wastewater energy recycling method

Abstract: An auxiliary process and method for use in wastewater treatment plants, modifying conventional primary and secondary treatment, to condition the effluent for use as agricultural irrigation water containing liquified fertilizer and soil amendment materials. Primary sludge and skimmed materials are comminuted and added to the volume of organic materials available for secondary treatment. A bacterial inoculum is added to accelerate the microbial reduction of biodegradable materials into a biomass of cells. The separated predominantly cellular secondary sludge is processed to rupture the cellular structure thus releasing the protoplasm to colloidal suspension. Combined with the mainflow of secondary clarified effluent, the resultant micro-particulate effluent is thereby conditioned for effective chelation treatment to remove heavy metal ions and for effective disinfection with reduced requirements for toxic reactants. The product is discharged as agricultural irrigation water containing, in solution, agricultural fertilizers as nitrogen, minerals, carbonaceous compounds and oxygen, plus ligno-cellulose soilbuilding materials. The heavy metals may be separated and recycled as a by-product.

Infectious Disease Hazards of Landspreading Sewage Wastes

Abstract: Major increases are currently taking place in the United States in the application of sewage wastes to agricultural land. This paper reviews literature relating to the question of whether such applications involve hazard from human disease organisms. Evidence on the matter is still inadequate. Processed sewage wastes often contain residual pathogenic viruses, bacteria, cysts of protozoa, and ova of helminths, but most sewage-related disease outbreaks have been attributed to use of raw sewage waste water, raw sludges, or night soils on food crops consumed raw, to contamination of drinking water from septic tanks, or to consumption of raw shellfish from sewage-polluted waters. Although subject to relatively high levels of exposure to pathogens in aerosols, waste water treatment plant workers appear to be unaffected, but data on this are limited. Percolation of waste water at a moderate rate through soils of medium to fine texture removes most bacteria and viruses; pathogen movement in surface runoff water may present a greater hazard for spreading disease. Techniques that completely disinfect sludges may fail to stabilize them so that putrefaction is a problem. Properly conducted composting stabilizes raw sludge and destroys most pathogens. Certain fungi and actinomycetes generated during composting may have allergenic potentialities of import for workers at sludge composting sites.

Handbook of advanced wastewater treatment.

Abstract: Handbook of advanced wastewater treatment , Handbook of advanced wastewater treatment , مرکز فناوری اطلاعات و اطلاع رسانی کشاورزی

Process and apparatus for waste water treatment

Abstract: Waste water containing organic pollutants is purified by biological treatment with aerobic microorganisms supported on hollow fibers having microporous walls through which oxygen is supplied to the microorganisms.

Process for nitrification of waste water

Abstract: Process for the nitrification of waste water in a trickle phase reactor whereby the gas containing molecular oxygen contains more than 25% by weight of molecular oxygen, the off-gas in the column is vented and / or recycled, during the nitrification 0.5-10% by weight of CO 2 , with respect to the total quantity of molecular oxygen present, such a quantity of the liquid effluent ofthe reactor is recycled that the entire column contents are irrigated and the gas and the liquid contact each other counter-currently. This process can be used for the nitrification of industrial waste water, especially waste water of fertilizer plants.

System for electrocatalytic treatment of waste water streams

Abstract: A continuous system for disinfecting waste water streams, such as sewage and streams containing organic matter and removing suspended solids therefrom is disclosed. A waste water stream is passed into an electrolytic cell open to the atmosphere and between a series of electrically charged parallel electrode plates. A controlled amount of electrolyte such as sodium chloride is added to the waste water stream before it passes through the electrolytic cell. During passage between the electrode plates a foam is generated which entrains suspended selected nutrient solids contained in the waste water stream, the foam removed by skimming and/or suction means. The treated water discharged from the electrolytic cell is filtered to remove additional non-nutrient suspended solids not entrained with the foam. A portion of the treated water from the electrolytic cell is recycled and reinjected into the influent stream. Control means are included to control residual chlorine in the effluent discharged from the electrolytic cell while maintaining high dissolved oxygen in the effluent.

Application of a biochemical fuel cell to wastewaters

Abstract: The system employed in the study was composed of a reactor for hydrogen production by the immobilized cells of C. butyricum, a fuel cell, and a reactor for wastewater treatment by the immobilized microorganisms. Industrial wastewaters were applied to the system. The rate of hydrogen production by the agar gel-entrapped whole cells was higher than that by the polyacrylamide gel-entrapped ones. The optimum flow rate for hydrogen production was observed with a packed-bed reactor. As the bacteria produced organic acids, the wastewater became acidic at the low flow rate. The rate of hydrogen production and the current increased when the flow rate and the BOD of the wastewater were increased. The diffusion of hydrogen to the electrode surface and the amount of hydrogen produced were the rate-determining steps of the current generation. The system was composed of three devices, the reactor for the hydrogen production, the fuel cell, and the reactor for wastewater reatment. This study provides an application of immobilized whole cells to energy conversion and wastewater treatment. 10 figures, 2 tables.

Domestic water system

Abstract: The specification discloses a domestic water system reclaiming waste water in which a tap water line supplies fresh water only to a kitchen sink and as a replenisher for a reclaim system supplying all the water to a toilet, a lavatory, a bath tub, a clothes washer, laundry tubs and a dishwasher. Drains from the toilet and the kitchen sink lead directly to a sewer, and drains from all the other installations lead to a clarifier tank having an overflow to the sewer. A pump pumps water from the clarifier tank through filter tanks to all the installations except the kitchen sink and to a hot water heater supplying the lavatory, the bath tub, the clothes washer, the laundry tubs and the dishwater. An inline instant hot water heater is positioned in the tap water line to a hot water tap of the kitchen sink.

Process for removing organic substances and nitrogen compounds from waste water

Abstract: An improved process for the removal of organic substances and nitrogen compounds from waste water by means of micro-organisms, wherein waste water to be treated is passed continuously through a denitrification zone, effluent from the denitrification zone is passed into a nitrification zone, and at least a portion of the effluent from the nitrification zone is recycled back to the denitrification zone. A portion of the waste water to be treated is fed directly into the nitrification zone as well as to the denitrification zone.

Wastewater and wastewater solid processing system

Abstract: A system and method for processing wastewaters, domestic, industrial or otherwise, including producing a substantially sterile and recyclable organic material from the effluent wastewaters, and for producing at the same time a substantially sterile and recyclable organic material from solid matter in the wastewaters. The process system is complete as to separation of solids and liquid and as to the processing of both liquid and solid phases. The liquid phase may be used for agricultural purposes or passed to a unit from which only pure water is dispersed by evaporation and transpiration to the atmosphere while dissolved and nondissolved solid matter is decomposed. The solids separated by the system are dewatered by expressing the water therefrom, the solids then being bagged in loose form or pressed into solid blocks which may be stored on a pallet. This part of the process may be accomplished by rollers, presses, and/or microwave drying.

Process and apparatus for the biological treatment of waste water

Abstract: Waste water to be treated is introduced into an enclosed gas tight oxygenation chamber An oxygen-containing gas is also introduced into the oxygenation chamber, at a pressure higher than atmospheric pressure, such that oxygen from the gas is dissolved in the waste water in a quantity higher than the saturation concentration value of oxygen in the waste water at atmospheric pressure, thereby superoxygenating the waste water The thus superoxygenated waste water, maintained at such pressure higher than atmospheric pressure, is then passed into an enclosed gas tight filtering chamber which is separate from the oxygenation chamber and which is also maintained at such pressure higher than atmospheric pressure No other oxygen, other than the oxygen dissolved in the waste water, is introduced into the interior of the filtering chamber The superoxygenated waste water is passed through a biological filter bed within the oxygenation chamber, thereby biologically purifying the waste water to form purified water which is then removed from the filtering chamber

Biological treatment of waste water

Abstract: A method for biologically purifiying waste water which produces substantially no excess waste sludge is provided. In this method, a waste water containing biodegradable substances is treated in a biological fixed film type reactor and aqueous water sludge discharged from the reactor is aerobically digested after being separated from the biologically treated waste water. The digested aqueous sludge is returned to the reactor or the upstream thereof. This method can be advantageously combined with any installed activated sludge type water purification process, to thereby substantially eliminate the production of excess waste sludge from the water purification system.

Flotation method and apparatus

Abstract: Aerated liquid injected into contaminated wastewater provides minute bubbles which ascend slowly and become attached to contaminants to buoy them to the liquid surface. To produce an intimate mix of the aerated liquid and wastewater, the aerated liquid is injected into the wastewater through opposed mutually confronting openings. Streams emerging from the openings collide to create an area of high turbulence.

Flotation device with pretreatment

Abstract: Methods and apparatus for treating water/wastewater to remove grit, susped and colloidal solids of organic and inorganic nature, microorganisms and surfactants. Dense suspended solids (grit) are first removed by a centrifugation process. The influent water/wastewater is then passed through coagulation and flocculation chambers, an upflow clarifier and a high-rate settling chamber for final sedimentation. Next, the influent passes through a foam filter to remove colloidal particles. The water/wastewater under treatment is then pressurized and saturated with air and subsequently depressurized, causing the dissolved gas to bubble out of solution floating out suspended contaminants. At this point, ozone is introduced into the influent to create a thicker, more dense foam by oxidizing organic matter and for disinfection purposes. The foam floated to the surface of the influent is scraped off and furnishes the foam for the foam filter.

Apparatus for clarifying waste water

Abstract: Apparatus for clarifying treated waste water in which the waste water is floated and settled in a flotation tank equipped with a rotatable carriage provided with multi-scoop means. The multi-scoop means is rotated as it is passed through the upper strata of the treated waste water for the removal of floated particles or sludge with no appreciable disturbance of the main body of waste water. The multi-scoop carries the floated particles or sludge to a sludge outlet in an efficient manner without clogging by an unique construction self-cleaning in operation.

Dynamics and control of the activated sludge wastewater process

Abstract: The dynamics of the activated sludge process are governed under certain conditions by interactions between the reactor and settler through sludge recycle. Settler underloading can lead to extremely sluggish system response, indicating that effective sludge height regulation is an important control objective. This objective may be in conflict with the need to maintain small variations in reactor solids concentration. An effective compromise can be achieved by using ratio control on both sludge recycle and settler underflow. This control policy does not require sludge storage.

Coagulation in Wastewater Treatment

Abstract: Most contaminants in wastewater are solid particles or associated with such particles; many are stable colloids. Consequently, effective treatment of wastewater requires effective solid-liquid separation. Furthermore, coagulation, which is considered here to involve the chemical destabilization of particulates and the physical transport of these destabilized particles to form larger aggregates, is an essential component of all wastewater treatment systems.

Water purification system

Abstract: Waste water is reclaimed for re-use by emulsifying with a water insoluble (or oil soluble), high molecular weight, anionic surface active oil, then breaking the emulsion by physical or chemical methods, thereby producing a coherent floc which occludes insoluble matter suspended in the water, then separating the floc from the purified water in a coherent mass.

Process for purification of sanitary waters

Abstract: A purification process for removal of suspended solids, carbonaceous material, nitrogenous material, phosphorus, refractory organics, bacteria and viruses comprises of combining and carrying out the various biochemical and chemical reactions and separation of the suspended solids in a single sludge system in a simplified process sequence suitable for use in a single reaction tank. The biooxidation, nitrification, denitrification and chemical precipitation processes are carried out in presence of mixed microbial population entrapped into fluidized nonbiodegradable suspended solids with portion of the fluidized suspended solids circulating through three reaction zones having varying concentration of disolved oxygen to maintain environmental conditions to support growth of the microbial population and simultaneously to maintain operating conditions required to carry out the involved reactions. The fluidized suspended solids entrap the active microorganisms, colloidal matter and suspended solids present in the incoming waste water and/or generated during purification of the waste water, improve the settling properties of the resulting sludge and enhance separation of suspended solids from the purified waste water. The concentration of the active microbial population in this purification process is significantly higher than that achieved by the prior art processes resulting in better performance, more efficient removal of pollutants and reduced treatment costs. The followed chemical oxidation provides for removal of remaining impurities and killing of bacteria and viruses.

Kinetic Studies on the Lime Sulfurated Solution (Calcium Polysulfide) Process for Removal of Heavy Metals from Wastewater

Abstract: A new process has been developed for wastewater purification, utilizing “Lime Sulfurated Solution” as a coagulant. Calcium polysulfide, the main component of this solution, decomposes in water on contact with a gas (atmospheric air or CO2 gas) and reacts with heavy metals. The heavy metals are removed as practically insoluble precipitates. The kinetics of this process were studied in a batch stirred tank vessel to obtain the fundamental data needed for development of a commercial continuous process. The findings are as follows: (1) Processing of bivalent metals Hg2+, Cd2+, Zn2+, Pb2+, and Cu2+ are completed in a few minutes to achieve the water quality standards in Japan. (2) Cr3+ is flocculated as Cr(OH)3 by the strong alkaline base of CaSx solution. It takes about 60 minutes for the precipitation with CO2 blowing, and 30 min with aeration. Cr(VI) is quickly reduced to Cr3+ and removed as Cr(OH)3. (3) A simulated wastewater simultaneously contaminated with 6 kinds of heavy metals can be brought well with...