Showing papers on "Wastewater published in 1983"

Fate of nitrogen and phosphorus in a waste water retention reservoir containing aquatic macrophytes

Abstract: Potential use of retention/detention reservoirs stocked with vascular aquatic macrophytes was evaluated, using a microcosm reservoir for reducing the N and P levels of agricultural drainage effluents (waste water). The treatments evaluated were reservoirs stocked with (i) pennywort (Hydrocotyle umbellata L.), (ii) water hyacinth (Eichhornia crassipes [Mart] Solms), (iii) cattails (Typha latifolia L.) and elodea (Egeria densa P), and (iv) control (no macrophytes). Labeled "N was used to differentiate preferential uptake of "1NH4* and "NOj-, and to follow the fate of added "NH.* and "NO,-. Results showed that 34 to 40% of the added inorganic "N ("NH/ + NOr) was removed through plant uptake, while 45 to 52% of the added "N was unaccounted for, presumably lost through NH, volatilization and nitrification-denitrification processes. In the control reservoir, algal biomass removed 4.4% of added "N, while 41% of the added "N was not accounted. Pennywort and cattail-elodea systems were found to be most effective, with about 50% inorganic N removal in a 4-day detention period. All aquatic macrophytes preferred "NH4* over "NO3-, but the difference in uptake was not significant, except for pennywort and cattails, which removed 84 and 92% of the added "NH4* as compared to 16 and 8% of the added "NO3-, respectively. About 25 to 29 d were required by the systems with macrophytes to remove 50% of the wastewater P. Plant removal of P was in the range of 3 to 65% of added P, while 7 to 87% of the added P was lost through precipitation and adsorption reactions. Additional Index Words: water hyacinth, pennywort, cattails, elodea, aquatic system. Reddy, K. R. 1983. Fate of nitrogen and phosphorus in a waste water retention reservoir containing aquatic macrophytes. J. Environ, qual. 12:137-141. Vascular aquatic macrophytes such as water hyacinths (Eichhornia crassipes [Mart] Solms), duckweed (Lemna minor), and cattails (Typha sp.), cultured in ponds and reservoirs, offer potential alternatives for treating sewage and industrial effluents (Boyd, 1969; Wooten and Dodd, 1979; Wolverton and McDonald, 1979), and agricultural effluents (Reddy et al., 1982). The capacity of vascular plants to assimilate nutrients from polluted waters has been recognized for several years (Rogers and Davis, 1972; Stewart, 1970; Boyd, 1976). Nutrient removal efficiency of a system containing plants will depend on the type of aquatic plant, growth rates of plants, nutrient composition of the water, and physicochemical environment in the water. Studies reported by several researchers (Clock, 1968; Scarsbrook and Davis, 1971; Cornwell et al., 1977) calculate the nutrient removal rates, based on the changes in concentrations at the inflow and outflow of a pond or reservoir. Although these calculations provide information on the nutrient removal efficiency from waste water, they provide very little understanding on the rate of N and P removal in these systems. Presence of aquatic macrophytes in a pond alters the physicochemical environment of the water, and the role of these changes are often ignored in evaluating the efficiency of a biological treatment system. The dense cover of floating water hyacinths depletes dissolved O2 of the underlying water, thus creating anaerobic conditions (Reddy, 1981). These conditions favor the denitrification process, thus maximizing NO3" removal. Presence of submersed plants, such as elodea or algae, can deplete dissolved CO2 in the water during the periods of high photosynthetic activity (mid-afternoon) and increase the dissolved O2 of the water, thus resulting in increased water pH (Reddy, 1981). This condition can maximize NH/ removal through volatilization and soluble ortho-P removal by chemical precipitation. The role of underlying sediments of a pond or reservoir as a nutrient source or sink to the overlying waters is often ignored in calculating the nutrient removal efficiencies. In central Florida, organic soils (Histosols) planted with vegetable crops are artificially drained during wet seasons, and the drainage effluent discharged from these fields is being pumped into retention/detention reservoirs and subsequently into Lake Apopka. These retention reservoirs are needed to reduce the nutrient ' Florida Agricultural Experiment Stations Journal Series no. 3766. Received 6 Mar. 1982. 2 Associate Professor, University of Florida, Inst. of Food & Agricultural Sciences, Agricultural Research & Education Center, P.O. Box 909, Sanford, FL 32771. J. Environ. Qual., Vol. 12, no. 1,1983 137

Anaerobic filters for the treatment of coal gasification wastewater

Abstract: A process train consisting of the following sequence of unit processes, a berl-saddle-packed anaerobic filter, an expanded bed, granular activated carbon anaerobic filter, and an activated sludge nitrification system was evaluated for the treatment of a synthetically prepared coal gasification wastewater. The first-stage anaerobic filter resulted in very little removal of organic matter and no methane production. Excellent reduction in organic matter occurred in the granular activated carbon anaerobic filter. The removal mechanism was initially adsorptive and near the end of the study, removal of organic matter was primarily through conversion to methane gas. It is felt that the success of the activated carbon anaerobic filter was due to the ability of the activated carbon to sequester some components of the wastewater that were toxic to the mixed culture of anaerobic microorganisms. The activated sludge nitrification system resulted in complete ammonia oxidation and was very efficient in final effluent polishing.

Treatment of coal gasification wastewater with anaerobic filter technology

Abstract: Coal gasification has been regarded as a promising technology for the production of the gaseous fuels needed to supplement dwindling reserves of petroleum and natural gas. The organic constituents of coal gasification wastewater are 60 to 80% phenols. The first-stage, berl-saddle-packed anaerobic filter resulted in very limited reductions in DOC, COD, and the specific organic compounds monitored. Excellent removal efficiencies of DOC, COD, and the specific organic compounds were realized in the completely mixed, expanded-bed anaerobic granular activated carbon filter. The activated carbon offers a larger sheltered microbial attachment area than does the berl-saddle plastic medium. The success of the activated carbon packed filter is probably due to surface adsorption. Some of the mass of the retained COD may represent the fraction of the feed constitutents that is nonbiodegradable in and inhibitory to the anaerobic environment. 11 figures, 4 tables. (DP)

Method and apparatus for treating organic wastewater

Abstract: A method and apparatus for achieving high quality treatment of organic waste water (both domestic and industrial types), which can also be used to treat organically contaminated water supplies or to reduce hazardous organic wastes (cyanides, PCBs, etc.) The apparatus operates at elevated pressures (up to about 35 psig), at high levels of dissolved oxygen (over 5 PPM), and at high concentrations of activated sludge (about 10,000 mg/l, MLSS). It consists of four separate process compartments (2 aeration compartments, a separator and a clarifier) which are contained within three vessels or alternatively in two vessels. The process compartments are linked in series by passageways and by piping and are maintained at a uniform pressure using a common manifold. The process is designed for simplicity of operation, compactness, and maintenance by a single part time attendant.

Process and apparatus for the biological purification of waste water

Abstract: 1. Process for the biological purification of waste water, in which the waste water is mixed with activated sludge in an activated sludge basin in the presence of carrier particles for microorganisms, and an oxygen-containing gas is passed in, the waste water/activated sludge mixture is then passed, via an outlet into a secondary settling tank while retaining the carrier particles, and purified waste water and activated sludge are separated in the secondary settling tank, and in which activated sludge is transported back from the secondary settling tank into the activated sludge basin, characterized in that the carrier particles are retained, with the aid of a partition which is impermeable to carrier particles, in a region of the activated sludge basin which is in front of its outlet and in which the flow rate of the waste water/activated sludge mixture is low compared with that at the outlet, additional gas being introduced in front of and behind the partition, and in that the introduction of additional gas behind the partition is carried out below the introduction of additional gas which takes place is front of the partition and far below the outlet opening of the activated sludge basin, and the introduction of additional gas is adjusted so that the carrier particles present in front of the partition are forced away from the latter.

Nitrogen and phosphorus removal from wastewater

Abstract: Wastewater is passed sequentially through an anaerobic treating zone and an oxic treating zone, followed by separation from the treated liquor of a dense sludge containing activated biomass, a least part of which is recycled to provide the activated biomass employed in treating the influent wastewater. Of the part of the sludge so recycled a minor portion is introduced into the anaerobic treating zone for admixture with the wastewater influent and the remaining major portion is introduced into the oxic treating zone, into which oxic zone oxygen-containing gas is admitted to effect oxygenation of the contents of that zone.

Activated sludge treatment of synthetic wastewater containing pentachlorophenol.

Abstract: Activated sludge treatment of a pentachlorophenol (PCP)-containing synthetic waste was examined. With a waste containing some sugars, and 40–120 mg/L PCP, laboratory activated sludge required about seven days for acclimation. However, the prior addition of a quasipure culture of PCP-metabolizing Arthrobacter resulted in immediate acclimation. Even with acclimated sludge, however, the system was upset for two days by a simple step change from 40 to 120 mg/L of PCP. The stability of the system to such a shock load was considerably improved when a chemostat culture of the PCP-metabolizing Arthrobacter was fed slowly into the mixed liquor. Kinetic models were developed to describe the dynamic response of the system in terms of growth parameters, hydraulic detention time, sludge age, and bleed-in rate from the chemostat.

Removal of phosphates and BOD from wastewaters

Abstract: The treatment of wastewater with activated biomass to remove BOD and phosphorus values in a system in which the wastewater influent is initially mixed with recycled active biomass in an anaerobic zone and then subjected to aeration in an oxic zone, wherein the residence time of the mixed liquor in the oxic zone is reduced. At least part of the biomass-containing sludge separated from the mixed liquor subjected to further oxidation in a separate zone before admixture with the wastewater influent.

Process and apparatus for the biological purification of phosphate-containing wastewater

Abstract: This invention relates to a process for the biological purification of phosphate-containing wastewater wherein the wastewater is gas-treated, i.e. aerated, in an oxygenation tank in the presence of activated sludge for degrading organic hydrocarbon compounds and absorption of phosphate by microorganisms present in the activated sludge. The wastewater-activated sludge mixture is then withdrawn from the oxygenated tank and divided, in a post clarification stage, into purified, essentially phosphate-free water and phosphate-containing sludge. The phosphate-containing sludge is recycled, at least in part, into the oxygenation tank. A partial stream of wastewater-activated sludge mixture is branched off from the oxygenation tank, and/or recycle sludge is branched off as a partial stream from the post clarification stage, and the mixture is subjected to flotation treatment for thickening. A thus-obtained, low-phosphate flotage, i.e. subnatant liquor, is discharged from the flotation unit. Likewise, resultant, phosphate-rich flotage sludge, i.e. thickened floating sludge, is discharged and heated, and after this heating, is treated anaerobically and mixed with wastewater to be purified. Subsequently, the wastewater-flotage sludge mixture is subjected to a phosphate separation and thus-produced, low-phosphate sludge is recycled into the oxygenation tank, and phosphate-enriched liquid is further treated.

Removal of organic contaminants from coal conversion process condensates

Abstract: Experiments were carried out to evaluate treatment characteristics of a phenolic coal gasification process wastewater in which major treatment steps included solvent extraction with methylisobutyl ketone for phenol recovery and steam stripping for ammonia removal, followed by either activated sludge (AS) or powdered activated carbon-activated sludge (PAC/AS) processing. The study showed that solvent extracted wastewater did not require dilution prior to biological treatment; also, solvent extraction provided for lower effluent COD, TOC and colour for either AS or PAC/AS treatment, with the latter process showing better removal for these constituents. Activated sludge effluent showed favourable granular activated carbon adsorption characteristics, and lime-soda softening was demonstrated with PAC/AS effluent.

Concentration of coliphage from water and sewage with charge-modified filter aid.

Abstract: Methods of detecting and concentrating animal viruses from large volumes of water and wastewater have experienced rapid development in recent years, but only a few methods are available for the concentration of bacteriophages The present study describes the use of a charge-modified (Zeta Plus) filter aid (AMF Cuno, Meriden, Conn) for the concentration of coliphages from large volumes of water and sewage Coliphages MS-2 and f2 were efficiently adsorbed from water and sewage to the positively charged filter aid Elution was accomplished with 4% beef extract--05 M NaCl adjusted to pH 95 The recovery of f2 from 10- to 20-liter volumes of tap water ranged between 11 and 70%, and the recovery of MS-2 ranged between 43 and 70% The efficiency of recovery of naturally occurring coliphages from secondarily treated sewage ranged between 16 and 44% This technique appears to be promising because it requires low-cost equipment (47-mm polypropylene filter housing), is easy to handle, and can filter large volumes of water (greater than or equal to 20 liters) with good recoveries Filtrations can be conducted at the ambient pH of the water, and the unit cost per filtration (ie, the cost of filter aid) comes to less than three cents per sampling The technique could be useful in evaluation of viral water quality, study of ecology and occurrence of phages in natural waters, and isolation of rare phages from natural waters

Process for the oxidation of hydrogen sulphide dissolved in the waste water from a coal gasification process

Abstract: Hydrogen sulphide in the waste water from a coal gasification installation is subjected to an oxidizing treatment in the presence of the very fine-grain residual coke which, being washed out of the product gas, is suspended in the waste water, the residual coke particles thus serving as a catalyst. When using air for the oxidation treatment, with the usual period of treatment, it is possible to achieve virtually quantitative conversion of the hydrogen sulphide to sulphate. If the solid particles are to be removed from the waste water by a flotation step, the flotation operation and the oxidizing treatment can be performed simultaneously in a common apparatus.

Method for removing and recovering nutrients from wastewater

Abstract: A B S T R A C T METHOD FOR REMOVING AND RECOVERING NUTRIENTS FROMWASTEWATER A method for removing and recovering ammonium and/or potassium and/or phosphate ions from wastewater is presented which comprises: - permitting said wastewater to pass through at least one bed of ion-exchange resins capable of removing selectively those nutrient ions - regenerating those ion-exchange resins with a Na Cl solution or other suitable regenerant solutions so that said nutrient ions may be obtained in a much more concentrated form - adding to said regeneration eluates (or, eventually, directly to wastewater) at least one Mg salt, in proper pH conditions so as to precipitate hydrous MgNH4PO4 and/or MgKPO4, slightly soluble salts of great agronomic value.

Mass transfer of volatile organic compounds in packed tower aeration

Abstract: Synthetic organic chemicals (SOCs) are frequently found in significant quantities in industrial and municipal wastewaters as well as in leachate from hazardous waste disposal sites. Con tamination of drinking water supplies may occur from either of these sources and is a serious public health concern. Of the SOCs currently identified in wastewaters and water supplies, many are relatively volatile and removal may be achieved through aeration. Where feasible, aeration is generally cost-ef fective, particularly when compared with adsorption processes, such as treatment with granular activated carbon. Aeration processes that have been applied to the removal of volatile organic chemicals (VOCs) include diffused aeration, surface aeration, spray aeration, and counter-current packed tower aeration. Of the available aeration processes, counter current packed tower aeration is often the most cost-effective design when removals greater than 90% are required. Although packed tower aeration has been well documented in the chemical engineering literature,1"12 its use specifically for controlling trace synthetic organics is a relatively new concept in the drinking water industry. Recently, however, air stripping of VOCs in packed towers has been studied by a number of researchers,13"28 and several case studies have been reported. Diffused aeration for VOC removal also has been a subject of considerable recent attention, 1316'21~23'29'30 as has the volatization of SOCs during the surface aeration of wastewater.29"32 Many of the recent case studies on VOC removal in packed tower aeration have not been published, and for those published, complete information is often unavailable. Few attempts have been made to generalize pilot results to conditions or compounds other than those studied. Design applications, even when well conducted, generally lack a systematic approach for determining optimum design criteria based on the results of pilot studies. Mass transfer coefficients increased with loading rates, and for most compounds, correlations with existing models were adequate. This article presents a design model for evaluating packed tower aeration and examines how pilot operation can be used to generate the mass transfer information required for design. The results from recent pilot work on a contaminated source (Potomac tidal fresh estuary water mixed in equal parts with nitrified wastewater effluent) are presented, and the results are applied to a design optimization for a hypothetical full-scale application. This work was part of a larger study conducted for the Bal timore District of the U. S. Army Corps of Engineers. The study investigated the feasibility of treating Potomac tidal fresh estuary water, mixed with equal parts of nitrified secondary wastewater effluent, as a simulated future water supply. In this context, the 3 785 m3/d (1 mgd) Experimental Estuary Water Treatment Plant (EEWTP) was operated and evaluated. Air stripping was evaluated on a smaller scale of 20 to 380 m3/d (2 to 35 gpm), using an influent of plant water spiked with five volatile organic compounds.

Toxicity of a Complex Munitions Wastewater to Aquatic Organisms

Abstract: The toxicity to freshwater organisms of a complex munitions effluent called condensate wastewater was determined using a novel and relatively economical approach proposed by Pearson and co-workers at the Second Annual ASTM Symposium on Aquatic Toxicology. Applicable only to complex wastewaters in which the concentrations of the individual chemical components are relatively constant over time, the approach emphasizes performing toxicity and related tests on a chemical mixture representative of the actual wastewater, with secondary attention being directed toward testing the individual chemical components, which is the conventional approach. The testing program comprised several series of static acute toxicity tests on authentic wastewater, artificial wastewater, and selected components to identify the conditions under which they are most toxic and to identify the most sensitive species; a series of flow-through acute toxicity tests on the artificial wastewater using the most sensitive species; a series of short-term bioconcentration tests; several early life-stage tests; and, finally, several life-cycle chronic tests. Twelve species representing three trophic levels were employed in the program. It was concluded that the approach economically and rapidly provided a sufficient data base for assessing the effects of the wastewater on aquatic life. Two modifications were recommended to decrease the cost andmore » time of obtaining the data. One was to perform a static and a flow-through test early in the testing program to identify the most appropriate exposure condition to use in the initial portion of the program. The other was to compute the octanol-water partition coefficients of the organic components of the wastewater before performing any bioconcentration test and to use the coefficients to determine if bioconcentration tests are necessary.« less

Determination of total cyanide in thiocyanate-containing wastewaters

Abstract: Utilisation d'EDTA, a pH 4, pour deplacer le cyanure des complexes metalliques et pour eviter la conversion de thiocyanate en cyanure libre quand des oxydants sont presents. Dosage spectrophotometrique du cyanure a l'aide de pyridine et d'acide barbiturique

Removing uranium by current municipal water treatment processes

Abstract: Uranium is an essential constituent of many naturally occurring minerals These minerals are found primarily in the eastern United States, the Congo, and Canada‘,’ Because of uranium’s high solubility, it is found in surface waters and groundwaters and, subsequently, in drinking water It may also he present in wastewater from uranium mining and milling operations and nuclear fuel processing plants Small amounts of uranium