Showing papers on "Wastewater published in 1977"

Introduction to wastewater treatment processes

Abstract: Introduction to Wastewater Treatment Processes, Second Edition presents the principles of chemical kinetics, reactor design, and the mechanism of biological treatment processes. This book provides the numerical applications that illustrate the treatment of laboratory data. Organized into eight chapters, this edition begins with an overview of the engineering design of process plants for treatment of wastewaters of industrial or domestic origin. This text then examines the various empirical methods for evaluation of concentration of contaminants in wastewaters. Other chapters consider the various types of primary treatment of wastewater, including sedimentation, screening, flotation, and neutralization and equalization. This book discusses as well the stationary film theory applied to the case of oxygen transfer. The final chapter deals with tertiary or advanced wastewater treatment, which consists of processes designed to achieve higher effluent quality than conventional secondary treatment. This book is a valuable resource for practicing engineers and students who are interested in the field of wastewater treatment.

Buoyant contact surfaces in waste treatment pond

Abstract: A wastewater treatment and reclamation system using natural ecological processes consisting of ponds; greenhouse pond cover; pollution-consuming, floating aquatic plants; high-surface-area, submerged, activated bio-web substrates for greatly increasing fixed bacterial film area and activity; aeration co-functioning with the bio-web substrate for accelerating bacterial metabolism and/or solar heat transfer, mixing and aerating the water body; and a polyculture of micro-invertebrates, fish and shellfish providing a balanced food chain for maximum removal and bio-concentration of nutrients and organics from the wastewater.

Process for treating waste water

Abstract: The invention provides processes for treating waste water comprising subjecting waste water to liquid phase oxidation without catalyst, liquid phase oxidation with catalyst and anaerobic digestion and/or aerobic treatment.

Virus and bacteria removal from wastewater by rapid infiltration through soil.

Abstract: A rapid infiltration land wastewater application site, composed of unconsolidated silty sand and gravel, which has been in continuous operation for over 30 years was examined for the accumulation and/or migration of a tracer virus (coliphage f2), indigenous enteroviruses, and enteric indicator bacteria in the soils and underlying groundwater. Tracer f2 penetrated into groundwater together with the front of percolating primary effluent and was not observed to concentrate on the upper soil layers. The tracer virus concentration in a 60-foot (about 18.3-m)-deep observation well directly beneath the wastewater application area began to increase within 48 h after application to the soil. The tracer level in this well stabilized after 72 h at a level of approximately 47% of the average applied concentration. Indigenous enteroviruses and tracer f2 were sporadically detected in the groundwater at horizontal distances of 600 feet (about 183 m) from the application zone. Laboratory soil adsorption studies confirmed the poor virus adsorption observed at the site. This was especially true on surface soils when contained in wastewater. Enteric indicator bacteria were readily concentrated on the soil surface by filtration on the soil surface mat. However, during tracer f2 virus tests, comparison studies with fecal Streptococcus revealed that bacteria capable of penetrating the surface were able to migrate into the groundwater. They were detected at the same locations as tracer and enteric viruses.

Removal of nutrients from treated municipal waste water by wetland vegetation

Abstract: Wildwood, Florida, population approxi mately 2 500, has been releasing secondarily treated wastewater effluent into a mixed hard wood swamp for 20 years. Wild wood is located in the central portion of Florida and is sur rounded by the characteristically low, flat topography of the region. Because this land is often inundated, it is not readily adaptable to development. Natural waterways usually consist of the shallow streams which empty into a wetlands area, which in turn often borders a shallow lake. The swamp into which Wildwood releases its wastewater effluent ex tends about 8 km (5 miles) south of Wildwood and borders Lake Panasoffkee. Prior to and during this study, the Wildwood wastewater treatment facility consisted of a trickling filter plant with a capacity of 950 m3/d (0.25 mgd). However, during the last few years, the plant has not operated properly and the effluent has received little more than primary treatment. At the start of this study a new activated sludge treatment plant was under construction. The Florida Department of Environmental Regulation was concerned that nutrients from the wastewater effluent might reach Lake Panasoffkee, making addition of tertiary treat ment facilities at Wildwood desirable. Recent studies 1?2 have shown that spray irrigation of wastewater effluent is one effective method of water recharge involving a natural system. This process, however, does involve some cost in elaborate transport and distribu tion equipment. In Florida these distribution costs can be reduced by using a wetlands sys tem. Wetland systems are well suited ?For receiving large volumes of nutrient-laden water for two reasons: 1) the wetland system dis perses water from a point source over a large area; 2) the vegetation itself is adapted to filter nutrients from the water. Swamp systems have been reported by Carter 3 to have a very high productivity of 990 to 1 170 g/m2-y. High productivity derives from the swamp's acting as a filter to trap nutrients from the water and store them in plant biomass. The high pro ductivity and filtering functions of swamps are characteristics comparable to a salt marsh.4 Studies done in a North Carolina salt marsh by Marshall5 have shown the effectiveness of nu trient uptake by marsh vegetation receiving municipal wastes. The Spartina biomass in the experimental marsh increased significantly in the area receiving municipal wastewater. Kitchens et alG and Wharton 7 report that river floodplain swamps functioned effectively as a nutrient sink for both urban and agricultural waste.

Method and unit for wastewater treatment by microorganisms

Abstract: A method and a unit for wastewater treatment with microorganisms, in which at least one non-woven fibrous mat having a three-dimensional network structure is disposed as a supporting media in an aeration tank, microorganisms are retained on the surface of and in the interstices of the non-woven fibrous mat, and organic polluting matter in the wastewater is oxidatively decomposed by the microorganisms in the presence of oxygen.

Nitrification-denitrification of wastewater

Abstract: In activated sludge-type wastewater treatment, nitrified oxygenated liquid-solid from the oxic zone is retained under anoxic conditions for denitrification and release of nitrogen gas, and the denitrified liquid-solid returned to the oxic zone.

Device for treating waste water

Abstract: A system for continuously treating waste water from laundries, car washers and like cleaning establishments to recover water soap, detergents, and other chemicals. The process of using the system is carried out by flowing the untreated water through sand chambers to remove heavy sediment, collecting the water from the sand chambers in a storage compartment, pumping the water through a centrifugal separator for removal of large particulate matter and then through a filter containing media for removal of flocculated soaps, detergents, waxes, and other particulate matter, thence into a filtered water storage compartment. The water is pumped from the filtered water storage compartment by a pressure pump. Part of the water containing unused soaps, detergents, conditioning agents, and other chemicals is returned from the filtered water storage compartment for reuse, the other part enters a filter containing absorptive media for removal of the remaining soaps, detergents, conditioning agents, organic compounds and other chemicals. The water is thence returned as pure rinse water to the cleaning establishment. Backwash water from the filters is returned through a separate bag filter recovering the water and leaving behind solids in the bag for removal and easy disposal.

Apparatus for the treatment of wastewater

Abstract: Apparatus for the treatment of wastewater has an enclosed unit providing a facultative zone wherein a mixture low in dissolved carbon comprising raw sewage and partially processed sewage undergoes denitrification brought about by faculative organisms contained in the prevailing low oxygen environment. Effluent from the facultative zone is charged into an enclosed columnar oxidation unit where a controlled flow of air or oxygen oxidizes nitrogen compounds present in raw sewage into nitrates. Part of the effluent from this columnar oxidation unit wherein the limited flow of oxygen has been mostly consumed in oxidizing the nitrogen compounds and is low in dissolved oxygen is recycled to the facultative zone and part flows into a columnar denitrification zone wherein anaerobic microorganisms substantially completely remove nitrogen as gas from the nitrates producing an effluent with a low nitrate content. Columnar oxidation units and denitrification units are in essentially deep-bed filters. Desirably also the facultative zone is provided in a columnar unit.

Purification of waste water high in carbohydrates and simultaneous production of high protein feed product

Abstract: A method for purifying waste water high in carbohydrate while obtaining therefrom a high-protein feed product. The waste water is inoculated with yeast of the type that converts starch and sugars into more yeast. The pH is adjusted to desired levels, and then the inoculated waste is circulated and recirculated in conjunction with air in amounts that enhance the growth rate of the yeast. The purified liquid waste is then separated from moist solids, and a large proportion of the moist solids is harvested as feed material, while a smaller proportion is taken for use in recycle. The proportion to be recycled is sent to a treatment zone where the pH is lowered to approximately 3.5 and where antibiotics are added, the lowering of the pH and the antibiotics both serving to suppress a substantial portion of bacterial growth while enabling the yeast to grow. After a suitable dwell time, the treated material is used in the inoculating step as the inoculant.

Algae separation from oxidation pond effluents

Abstract: During the preceding two decades, thou sands of oxidation ponds or stabilization lagoons have been built by municipalities and industries to meet secondary wastewater treat ment objectives.1 Low capital costs accom panied by minimal operation and maintenance costs relative to conventional biological waste water treatment systems led to the rapid adop tion of these ponds wherever land was relatively inexpensive by designers concerned with treat ing small flows or seasonal wastewaters. De sign criteria based on organic surface loading rates and hydraulic detention times have been developed and adopted by most states. In general, well-designed and operated sta bilization lagoons have proven effective in re moving soluble organic material from waste waters. However, in recent years analyses of maturation and facultative lagoon effluents have indicated that effluent algae carryover can impose a significant oxygen demand on receiving waters.2? 3 Theoretical calculation of the oxygen demand created by algae destruc tion suggests that 1.58 mg of 02 are required to oxidize 1 mg of algae (dry weight) to C02 and water. Bare et al.? found that 1.11 mg 02 was required per mg of algae obtained from laboratory studies and 0.81 mg 02 per mg algae obtained from field studies. Varma and Digiano 5 reported that 0.67 mg 02 was re quired for each milligram of algae destroyed. Data resulting from algae obtained in both laboratory and field experiments during this study indicate an average oxygen demand of 1.19 mg 02/mg algae. Despite the cited differences in oxygen de mand per unit weight of algae, one can con clude that a significant oxygen demand is im posed on receiving waters by algae discharged from lagoon effluents. Only the removal or destruction of algae prior to discharge can sufficiently improve effluent quality so that lagoons can again be incorporated into low cost wastewater treatment systems. Some means of algae removal will have to be em ployed with many existing oxidation ponds or they will have to be replaced with expensive, conventional wastewater treatment systems in order to meet current effluent standards. The purpose of this study was to evaluate and characterize promising methods of algae removal from wastewater treatment systems. A review of the literature suggested that chem ical coagulation and flocculation followed by sedimentation or flotation would be the most likely methods of economically and reliably achieving algae removal under the conditions encountered in most wastewater lagoons. Algae can be described as hydrophilic bio colloids 6 with apparent negative surface charges.7 In addition, their small size, 3 to 15 fi, and low specific gravity further compli cate physical removal processes. Destabiliza tion of algae suspensions have been accom plished with lime,8 alum,1' 4'9 ferric sulfate,4 magnesium ions,8 and many synthetic organic poly electrolytes.6?9 As might be expected, the effect of each coagulant is dependent on pH, algae concentration, and other parameters.

Treatment of wastewater

Abstract: Process and apparatus for the oxidation of carbonaceous and nitrogeneous matter in wastewater by use of a mixture of biologically active slimes attached to partially submerged rotating contactors The biological contactors are mounted in a single-stage treatment unit and are supplied with wastewater at a controlled rate relative to the surface of the contactors and distributed substantially evenly over the contactor surface A denitrifying unit, located upstream from the single-stage treatment unit is supplied with wastewater and recirculated effluent from the single-stage treatment unit The denitrifying unit utilizes biologically active slimes attached to rotating biological contactors for the removal of carbonaceous matter from the wastewater supported by nitrate oxygen from the recirculated effluent

Waste water process for treatment of strong wastes

Abstract: Disclosed is a waste water process for the treatment of strong wastes. Generally the process comprises an activated sludge process for the purification of waste water comprising: feeding the waste water to a first aeration zone wherein oxygen is introduced into the waste water, and said waste water is contacted with activated sludge; passing the effluent from the first aeration zone to a first clarification zone where the water from the first aeration zone is clarified to separate suspended sludge particles from partially decontaminated water; recycling a portion of the separated sludge from the first clarification zone to the first aeration zone and passing the partially decontaminated water from the first clarification zone to a second aeration zone; adding about 5 to about 500 ppm powdered activated carbon to the partially decontaminated water from the first clarification zone; oxygenating the partially decontaminated water containing carbon in a second aeration zone wherein oxygen or air is introduced into the partially decontaminated water; passing the effluent from the second aeration zone to a second clarification zone where the water from the second aeration zone is clarified to separate suspended sludge and carbon particles from decontaminated water; and recycling a portion of the separated sludge and carbon from the second clarification zone to the second aeration zone and passing decontaminated water out of the second clarification zone. Preferably said first aeration zone comprises a multiple stage aeration zone wherein waste water is aerated to introduce oxygen into the waste water in a first stage and the effluent from the first stage is aerated in one or more stages downstream of said first stage.

Combined algae production - wastewater treatment and reclamation systems

Abstract: Treatment of municipal wastewater in High Rate ponds has been extensively studied in a multitude of outdoor pond units. The ponds are 35 to 50 cm deep with folding channels and are mixed and aerated by a rotor cage aerator. The suspended biomass is separated by flocculation and flotation yielding high quality effluent and algal “froth” containing between 5 to 10 percent solids to be further dewatered and drum dried. Average production of photoautotrophic algae reached 22gr m−2day−1 which constitute about 5.8 percent conversion efficiency of the photosynthetically available light. The photosynthetic oxygen supply reached over 35 gr m−2day−1 which constitute over two thirds of the oxygen demand for the aerobic degradation of the waste matter. Predominant algal species such as Scenedesmus dimorphus , Micractinium quadrisetum , Phytoconis sp . and Oocystis solitaria varied seasonally in the pond without any significant change in growth and productivity. Dried algae containing up to 4 percent aluminium (flocculant residue) were fed to carps ( Cyprinus carpio ) and to St. Peter's fish ( Tilapia galilea ) where 85 percent of the fish-meal portion of commercial diet (usually 15 percent of diet) was replaced by 30 percent algae in the feed (equal protein level). Fish weight gain and health were equal if not improved by this algae containing diet. The algae also served for feeding of young chicks (1–8 weeks) with no mal-effects where algae (containing aluminium) replaced 25 percent of the proteins in the diet. The economy of the overall system is based on the value of wastewater treatment, the added value of the final effluent high quality rendering its reuse for agricultural irrigation and the value of the harvested algae as a proteinaceous feed. Once the need exists for all three values, the system is highly competitive vs. any other wastewater treatment process where the proper climatic conditions and land availability exist.

Phosphate removal from wastewater

Abstract: In activated sludge-type wastewater treatment in which phosphate is taken up in the aeration zone, solids are concentrated in a separate zone to form phosphate-enriched sludge and phosphate is resolubilized in an anoxic zone, a major part of the latter is returned to aeration without intervening phosphate removal and phosphate wasting is solely from sludge.

Simultaneous treatment of SO2 containing stack gases and waste water

Abstract: A process for simultaneously removing sulfur dioxide from stack gases and the like and purifying waste water such as derived from domestic sewage in which a portion of the gas stream and a portion of the waste water, the latter containing dissolved iron and having an acidic pH, are contacted in a closed loop gas-liquid scrubbing zone to effect absorption of the sulfur dioxide into the waste water. A second portion of the gas stream and a second portion of the waste water are controlled in an open loop gas-liquid scrubbing zone, the second portion of the waste water containing a lesser amount of iron than the first portion of the waste water, contacting in the open loop scrubbing zone being sufficient to acidify the waste water which is then treated to remove solids originally present.

Removal of toxic metal ions from metal-finishing wastewater by solvent extraction

Abstract: Solvent extraction procedures are presented for the removal of chromium, cadmium, and zinc from metal-finishing wastewater. The procedures utilize a 25% Alamine 336-xylene solution as the extractant. The three metals can be extracted selectively or simultaneously using a 100 to 1 aqueous phase to organic phase ratio. All three metals can be stripped from the organic phase with better than 99.5% efficiency with 4 M NaOH. The regenerated reagent can be recycled and reused without any loss of extraction efficiency. The procedures are reproducible, rapid, and simple.

Waste water process

Abstract: A method is provided for the treatment of a waste water stream characterized by having toxic and corrosive properties due to the presence of a cyanides formates and a halide of a metal or ammonia comprising adding a ferrous ion to said waste water to convert the cyanides to iron cyanides, adding a base to said waste water until the pH of said waste water is adjusted to the range from about 9 to 11 to precipitate a sludge containing said iron cyanides, feeding said waste water to a biological reactor to convert said formates to carbon dioxide and a biological residue and recovering an environmentally upgraded waste water stream from said biological reactor.

Microbial aerosols from food-processing waste spray fields

Abstract: Federal legislation restricts the discharge of waste from various industrial processes into rivers, lakes, or other waters. For this reason disposal of wastewater by spraying onto cultivated, grassed, or forested lands has come into use. These waste disposal spray systems produce droplets of water containing suspended material that may become aerosolized as particles less than about 20 µ in diameter. Particles of this size will remain suspended in the atmosphere and will travel long distances downwind. The generation of such particles by commercial spray or sprinkler equipment may be presumed because regardless of the size distribution for water droplets leaving the sprinkler nozzle a number of particles of aerosol size will develop through rapid evaporation. Solid materials, including microorganisms, suspended in the water become the nuclei of the aerosol particles. Recent reviews have been published regarding the aerosolization of microorganisms in sprays resulting from the treatment and disposal of wastewater from domestic waste. Microbial aerosol particles were sampled up to 1.2 km downwind of the spray source. Katzenelson and Teltch reported aerosolized coliforms short distances downwind of spray fields for disposal of wastewater containing raw domestic waste and for disposal of effluent from a wastewater settling pond. In this report, studies were made of microbial aerosols downwind from spray fields for the disposal of potato processing wastewater.

Staging aeration for high-efficiency treatment of aromatic acids plant wastewater

Abstract: The performance of a multistage aeration system consisting of three tanks in series was investigated on a laboratory and plant scale for treatment of a high-strength waste stream containing several aromatic acids in addition to methanol and acetic acid in high concentration. The effects of shock loadings on the dissolved oxygen level and residual chemical oxygen demand were also studied. Experience with this mode of operation at several Amoco Oil Co. activated-sludge plants is summarized.

Industrial wastewater control1

Abstract: The reduction or elimination of industrial wastes at their in-plant sources is a more economical and more effective practice than their treatment at the plant outfall. Examples described, all selected from the food industries, are the hot gas blanching of vegetables, the dry peeling of fruits and vegetables by application of caustic, the recovery of useful by-products from whey, the reuse of poultry processing wastewaters and reduced water usage in the poultry industry, and material recovery from brewery, citrus, and fishery operations. All of these result in a smaller quantity of wastewater and pollutants going to treatment or discharge. End-of-pipe treatment is frequently required, even after all practical in-plant clean-up. Discharge into municipal sewers is discussed, as are the basic operations and processes available for pretreatment as well as for final treatment prior to discharge to a waterway. The author's premise is a plea for sharing of knowledge among different industries.