Showing papers on "Effluent published in 1987"

Quality Requirements for Irrigation with Sewage Water

Abstract: Irrigation is an excellent use for sewage effluent because it is mostly water with nutrients For small flows, the effluent can be used on special, well‐supervised “sewage farms,” where forage, fiber, or seed crops are grown that can be irrigated with standard primary or secondary effluent Large‐scale use of the effluent requires special treatment so that it meets the public health, agronomic, and aesthetic requirements for unrestricted use (no adverse effects on crops, soils, humans, and animals) Crops in the unrestricted‐use category include those that are consumed raw or brought raw into the kitchen Most state or government standards deal only with public health aspects, and prescribe the treatment processes or the quality parameters that the effluent must meet before it can be used to irrigate a certain category of crops However, agronomic aspects related to crops and soils must also be taken into account Quality parameters to be considered include bacteria, viruses, and other pathogens; total sa

Anaerobic/aerobic filter plant

Abstract: The biological filter of the instant invention is intended for use between a septic tank and a drain field and includes a filter tank which receives effluent from a septic tank. The filter tank contains therein aerobic and anaerobic treatment means for treating, simultaneously, aerobically and anaerobically, portions of septic tank effluent. The filter is operable to significantly reduce the levels of all contaminants found in septic tank effluent prior to the releasing of effluent into a drain field.

Performance of the duckweed species Lemna gibba on municipal wastewater for effluent renovation and protein production.

Abstract: An outdoor experiment was conducted in miniponds to evaluate the performance of Lemna gibba, a duckweed species, as a domestic wastewater stripper. Duckweed is one of the floating plants with a high capability of ammonia uptake and assimilation rate into valuable protein. The results indicate that under adequate operational conditions, depending mainly on the organic loading, the effluent quality meets irrigation reuse criteria and protein yield of the duckweed may reach 12 ton/ha per year, far above other conventional field crops.

Anaerobic treatment of slaughterhouse wastewater using the UASB process

Abstract: Effluents from the slaughterhouses, meat and poultry industries are heavily polluted and contain a high concentration of biodegradable organic materials. Therefore, the pollution capacity of these industries is high. Most of these industries discharge their effluents to a sewer or a watercourse.In order to comply with water pollution control standards and to reduce costs on sewer surcharges, these industries have to apply an adequate treatment of their effluents.Physical and chemical treatment methods as well as the conventional biological treatment processes are frequently applied in the treatment of these effluents. A combination of the methods are required where the effluent is to be discharged to surface waters, since no single treatment method will provide sufficient effluent.In the last decade, the high rate anaerobic wastewater treatment systems have become a good alternative for conventional aerobic as well as anaerobic biological treatment methods. The high rate anaerobic treatment systems were initially developed for the treatment of highly soluble low and medium strength wastewaters. These systems provided only a partial treatment of complex wastewaters containing a high fraction of suspended solids such as slaughterhouse wastewater.Investigations have shifted towards the application of high rate systems like the upflow anaerobic sludge blanket (UASB) for the complete treatment of agro-industrial wastewaters which are more difficult to handle, because they contain relatively high concentrations of suspended solids, i.e. complex wastewaters.Presently, the UASB system is the most widely applied high rate anaerobic system for complete treatment of such complex wastes.This thesis focuses on the question whether, and under which operationa conditions and environmental circumstances a one stage UASB mesophilic anaerobic treatment system is suitable for a complete treatment of slaughterhouse wastewater in practice.The feasibility of using the upflow flocculent anaerobic sludge blanket (UASB) process for a one stage anaerobic treatment of unsettled complex slaughterhouse wastewater, which contains approximately 50% of coarse insoluble COD, was investigated (Chapter 2). The continuous experiments were performed in a 25.3 m 3 UASB pilot-plant which was operated under semi-continuous conditions, viz. with a varying organic load over day and nighttime (i.e. high organic load during the daytime and with low organic load at night) and with weekend feed interruptions. The UASB pilot-plant was operated at a temperature of 30° C. In order to assess the feasibility of the process under conditions of lower temperatures the temperature was reduced to 20°C, 20 weeks after the start-up of the reactor.The data indicated that the system can satisfactorily handle organic loads up to 3.5 kg COD m -3 day -1 at a liquid retention time of 8 h at temperatures as low as 20°C. Temporary shock loads up to 7.5 kg COD m -3 day -1 during the day time at a liquid retention time of 5 h were accommodated satisfactorily provided such a shock load was followed by a period of low loading, e.g. at night.A significant discrepancy was found between the treatment efficiency in terms of COD reduction and to the lower calculated percentage of supplied COD total converted into methane-COD. This difference indicated that a significant portion of the achieved COD reduction was due to the accumulation of non- or slowly biodegradable substrate ingredients in the reactor. No differentiations could be made between the different types of substrate ingredients that accummulated in the reactor because the accumulated sludge was not characterized. However, a part of the accumulated substrate was converted to CH 4 in periods of feed interruptions.In Chapter 3 the feasibility of the upflow granular anaerobic sludge blanket process for a one-stage anaerobic treatment of slaughterhouse wastewater was investigated. The experiments were performed under semi-continuous operational conditions viz. continuous feeding at a constant organic load (24 h day) during the working days but with weekend feed interruptions, and process temperatures of 30°C and 20°C. Under a stable operation of the system, i.e. at a maximum COD reduction and a high conversion of COD into methane, the optimal loading rates that could be applied were 11 kg COD m -3 day -1 and 7 kg COD m -3 day -1 at 30°C and at 20°C respectively.The system was less effective in the removal of coarse suspended solids, compared to the removal of the colloidal and soluble fractions from the slaughterhouse wastewater.The data obtained in these investigations indicate that imposed prolonged loadings exceed the optimal loading rates, lead to deterioration of the specific methanogenic activity of the sludge, due to the accumulation of colloidal and soluble fractions of the wastewater in the sludge bed. Therefore, it was concluded that the system stability strongly depends on the processes involved in the removal of the colloidal and soluble compounds from the wastewater and their conversion into methane. As the predominant - non-biological-mechanisms underlying the elimination of these wastewaters pollutants were considered the entrapment and the adsorption mechanisms. The effect of these mechanisms on the rate of the liquefaction of the accumulated substrate - which is the required first step in their conversion into methane - were discussed.The different pollutant fractions of the wastewater, viz. the coarse suspended solids, the colloidal and the soluble compounds affect the performance of the UASB reactors because of the different mechanisms involved in the removal of these substrate ingredients and their subsequent conversion into methane. Therefore, these mechanisms were investigated in more detail. The results of these investigations are presented in Chapter 4. The experiments were performed in a one-stage flocculent sludge UASB-reactor under continuous operational conditions viz. continuous feeding at a constant organic load during 24 h a day and 7 days a week.The COD removal efficiency of the UASB reactor exceeded the COD removal efficiency as expected from the observed CH 4 production, indicating once again that non-biological mechanisms are involved. Two different non-biological mechanisms were distinguished in the removal of substrate ingredients from the wastewater. The entrapment mechanism prevailed in the elimination of coarse suspended solids, while mainly adsorption mechanisms are involved in the removal of colloidal and the soluble fractions of the wastewater.A continued accumulation of substrate ingredients in the reactor ultimately will become detrimental for the stability of the anaerobic treatment process, as it leads to sludge flotation and consequently could result in a complete loss of the active biomass from the reactor.After having demonstrated the principle feasibility of the upflow anaerobic sludge blanket (UASB) process for a one-stage anaerobic treatment of the slaughterhouse wastewater, we decided to assess the maximum possible extent of anaerobic degradation of the soluble, colloidal and coarse suspended solids fractions of the slaughterhouse wastewater (Chapter 5). In this way we intended to get a better insight in the real limitations of the system. All the experiments were performed at process temperatures of 30°C and 20°C, using membrane filtered wastewater (wastewater mf ), paper filtered wastewater (wastewater pf ) and total wastewater. The experiments were performed in a recirculated batch digester system with granular sludge. The experiments with the coarse suspended solids separated from the wastewater were performed with granular sludge as well as with flocculent sludge using conventional batch-fed stirred digesters. The maximum biodegrability percentages (i.e. conversion into methane) found at 30°C were 75% for wastewater mf , 61% for wastewater pf and 67% for wastewater total while at 20°C these values were 72%, 49% and 51% respectively. The maximum biodegrability of the coarse suspended solids fraction of the waste amounts to 50% at 30°C and 45% at 20°C.The mechanisms involved in the removal of the soluble and colloidal fractions of the slaughterhouse wastewater were thoroughly studied and elucidated. The data obtained in these experiments indicate that the prevailing mechanism in the removal of the soluble but especially also the colloidal fraction of the wastewater is an adsorption mechanism. The relatively high degree of adsorption of the colloidal fraction of the wastewater to the surface of the sludge, in combination with its high fat content, will deteriorate the specific methanogenic activity of the sludge. The adsorption of the colloidal materials will ultimately result in an enclosure of the granular sludge bacterial matter with a film of increasing thickness, and perhaps also density, which increasingly will hamper the supply of substrate to the bacteria present in the grains. The deterioration effect of fats towards the methanogenic activity of the sludge was explained on the basis of the inhibitory effect of the long-chain fatty acids of the neutral fats.As the extent of adsorption is very similar at lower and higher temperatures, but the rate of liquefaction of adsorbed compounds drops significantly at decreasing temperatures, it will be evident that the process can withstand considerably lower loading rates at 20°C as compared to 30°C.Therefore, it is concluded that the rate of liquefaction of the adsorbed insoluble colloidal fraction of the wastewater is the controlling factor with respect to loading potentials of the process and consequently that the temperature is the factor of predominant importance.

Nitrifying Bacteria in Wastewater Reservoirs

Abstract: Deep wastewater reservoirs are used throughout Israel to store domestic wastewater effluents for summer irrigation. These effluents contain high concentrations of ammonia (≤5 mM) that are frequently toxic to photosynthetic microorganisms and that lead to development of anoxic conditions. Population dynamics of nitrifying bacteria and rates of nitrification were studied in two wastewater reservoirs that differed in organic load and degree of oxygenation and in the laboratory under controlled conditions, both by serial dilutions in mineral medium and microscopically with fluorescein isothiocyanate-conjugated antibodies prepared against local isolates. The difference in counts by the two methods was within 1 order of magnitude. In the laboratory, an O2 concentration of 0.2 mg liter−1 was close to optimal with respect to growth of NH3 oxidizers on domestic wastewater, while O2 concentrations of 0.05 mg liter−1 supported significant rates of nitrification. It was found that even hypertrophic anaerobic environments such as the anaerobic hypolimnion of the wastewater reservoir or the anaerobic settling ponds are capable of sustaining a viable, although not actively nitrifying, population of Nitrosomonas spp. and Nitrobacter spp., in contrast to their rapid decline when maintained anaerobically in mineral medium in the laboratory. Nitrification rates of NH3 in effluents during storage in the reservoirs were slower by 1 to 2 orders of magnitude compared with corresponding rates in water samples brought to the laboratory. The factors causing this inhibition were not identified.

Decontamination of sites where organic compound contaminants endanger the water supply

Abstract: A method and system for decontaminating water, e.g., groundwater or process effluent, which is contaminated by small concentrations, e.g., in the range of 0.01 to 100 ppm, of dissolved volatile organic compounds (VOCs) includes introducing a flow of the water to an air stripping stage in which the water is directed through a packed column and air is directed through the column to air-strip organic molecules from the contaminated water; releasing the thus decontaminated water substantially free of the compounds to the environment; pretreating the organic compounds-carrying air in the substantial absence of water particles by a preheater; passing the heated air through a catalytic stage that oxidizes the organic compounds, and releasing the gaseous effluent from the catalytic stage to the atmosphere substantially free of organic contaminants. A system for decontaminating water contaminated by small concentrations of dissolved volatile organic compounds is also described, which includes apparatus for retrofitting an existing air stripper for this purpose.

Field evaluation of arsenic and selenium removal by iron coprecipitation: Final report

Abstract: The priority trace elements arsenic and selenium were removed from ash pond effluent by iron coprecipitation in a field study at the Carolina Power and Light Company's Roxboro Station. The study's broad objectives were to verify previously-derived laboratory results, confirm the technology's technical and economic feasibility, and develop information that could be used to make preliminary designs and cost estimates for full-scale treatment plants. The technology was tested at pilot scale in a continuous-flow system under field conditions. A chemical coagulation system was used of the kind typically employed for municipal and industrial water treatment. Arsenic was strongly removed (90% and above) with moderate iron dosages (14 mg/l to 28 mg/l Fe). Selenium removals were lower (56 to 80%) under comparable chemical conditions. Arsenic and selenium removals were strongly affected by solution pH. Testing indicated that process sludges can be gravity thickened, then dewatered with filter presses to 25 to 35% solids. Dewatered pilot sludges were determined to be not hazardous, as defined by Extraction Procedure (EP) toxicity test criteria. Costs to treat wastes similar to Roxboro ash pond effluent are estimated to be $345/million gallons (9.1 cents/cu m). However, costs will be different for plants that have wastewaters thatmore » differ in composition and volume from Roxboro ash pond effluent, or plants that have different treatment goals. Examples are provided to illustrate methods that can be used to make preliminary designs and cost estimates for different treatment scenarios. 30 refs., 62 figs., 29 tabs.« less

Renovation of used water from poultry processing plants

Abstract: A process for treating effluent water of a poultry processing plant for reuse in that plant. According to the present invention, a treatment of the effluent with a strong oxidant and with a substance to reduce the pH to less than 5.2 pH units, and preferably about 3.0±0.5 pH units causes a floc to form together with a destruction of bacteria and a breaking of the oils and greases. The floc contains the impurities such that the water separated from the floc is sufficiently purified for reuse in certain processing steps in the plant. In the case of treating effluent water from the poultry chiller tank(s), the product water can be reused in the tank(s). In the preferred form of the process, formation of the floc is enhanced by the addition of an anionic polymer or other thickener/strengthener, and separation is achieved by dissolved air flotation techniques. A final filtration can be utilized after a readjustment of the pH to near neutral to match new water to be used in the plant. Results of a pilot facility are given, with the results indicating that USDA standards for reuse of chiller water are met or exceeded. The process has been approved by USDA for use in conjunction with poultry processing plants. Significant economic savings are realized.

Effect of Pond depth on Bacterial Die-Off

Abstract: The depth dependence of bacterial die-off was demonstrated experimentally both in batch models and in three pilot-scale waste stabilization ponds with water depths of 0.5m, 1.0m, and 1.5m. The dimensions of the ponds in plan were 1.0 × 2.0m. The ponds were fed with secondary effluent of a two-stage trickling filter plant. An activated sludge treatment plant effluent was used in the batch models. It was concluded that the pond depth has a significant effect on the coliform die-off rate. The first-order die-off rate constant was found to be inversely proportional to the first power of the pond depth.

Process for upgrading water used in cooling and cleaning of raw synthesis gas

Abstract: This process relates to the upgrading of at least one stream of condensate water by removing water soluble gaseous impurities from the group consisting of HCN, COS, HCOOH, and mixtures thereof as produced in a process for the production of synthesis gas by the partial oxidation of solid carbonaceous fuel and/or liquid hydrocarbonaceous fuel. In the process, at least one internally produced condensate stream of water containing the aforesaid water soluble gaseous impurities is mixed with and vaporized into a stream of synthesis gas. The vaporized mixture is then introduced into at least one bed of catalyst where the gaseous impurities are removed by hydrolysis. The upgraded water stream is then recycled in the process for use in cooling and/or scrubbing the hot raw effluent gas stream from a partial oxidation gas generator. The condensate water streams are obtained by (i) cooling a portion of the cooled and scrubbed effluent stream of synthesis gas to below the dew point temperature; and/or (ii) cooling and flashing a portion of the quench water used to quench cool and clean the hot raw effluent stream of synthesis gas thereby producing a gaseous mixture comprising H 2 O, HCN, COS, HCOOH, and mixtures thereof and cooling said gaseous mixture to condense out and separate condensed water containing said water soluble gaseous impurities.

Method for treating waste water from a catalytic cracking unit

Abstract: A method for treating waste water from a catalytic petroleum cracking unit is disclosed. The method includes receiving step, aeration step, settling step, and a discharging step. In the receiving step waste water from which hydrogen sulfide and ammonium have been stripped out is introduced into a biological treatment tank. In the aeration step, the waste water in the tank is subjected to aeration for a predetermined period of time. In the settling step, activated sludge within the biological treatment tank is settled for a predetermined period of time. And in the discharging step, the supernatant is discharged from the tank subsequent to the settling step. The total duration of the aeration step performed daily is set to no longer than 12 hours and the aeration step is performed intermittently. If these conditions are met, yeasts which form pseudohyphae will grow actively enough to facilitate settling and separation of activated sludge. In addition, treatment of an undiluted waste water, which has been impossible with the conventional process of continuous activated sludge treatment, cna be realized by the method of the present invention and not only does this allow the waste water to be treated consistently without deteriorating the quality of effluent but also the amount of excess sludge occurring is sufficiently reduced to lower the load of sludge treatment.

Process for wastewater treatment

Abstract: Free cyanide-containing wastewater is treated to destroy the free cyanide content thereof by the step of treating said water with sulfur in the form of polysulfide in an integrated process wherein thiocyanate is also eliminated to produce a non-hazardous wastewater effluent and treating the wastewater in a second step with cultures of bacteria of the genus Thiobacillus in combination with nitrifying bacteria which oxidize ammonia to nitrite to nitrate. The first step is preferably carried out in the presence of a cationic surfactant, preferably a quaternary cationic surfactant, as a catalyst.

Apparatus for analyzing the annulus effluent of a well

Abstract: The disclosed invention is an apparatus for analyzing the annulus effluent of a producing well. The apparatus is designed to measure the flow rate of the annulus effluent, sample the annulus effluent and determine the quantities of each of the various phases of the annulus effluent. The apparatus is preferably mounted on a mobile vehicle and comprises a means for measuring the flow rate of the annulus effluent, a liquid vapor separator to split the annulus effluent into streams of entrained liquid and vapor, a separator to split the entrained liquid into the phases of oil and water, a sampling loop for extracting a sample of annulus effluent vapor which contains a condensor and a separator for splitting the fluid into its various phases, a means for measuring the amounts of all of the phases of the annulus effluent, and a means to record the data gathered. The apparatus is very useful in determining whether a producing well should be shut-in, worked over or left to produce "as is".

Process for eliminating ammonia and phosphate from waste water and process water

Abstract: In a process for eliminating ammonia and phosphate from waste water (effluent), magnesium salt and/or magnesium oxide and, if required phosphate and/or phosphoric acid are added. The salt MgNH4PO4 . 6 H2O is crystallised out and then separated off. The degree of elimination of the ammonium and of the phosphate in this case can be adjusted by the amounts of the abovementioned substances added. The pH is adjusted to between 7 and 10. The precipitation product contains nutrients valuable for agriculture. It can be provided for fertilising purposes.

Device for separating and extracting components having different densities from an effluent

Abstract: In a device for separating and extracting components having different densities from an effluent as applicable in particular to the separation of oil and water in crude oil, a single pump has the function of sucking the effluent into a separator and maintaining a pressure of higher value than the highest pressure which is necessary for extraction of one of the components. At least one regulator is provided for regulating the delivery of the lower-density component and at least one regulator is provided for regulating the delivery of the other component.