ISSN:1061-4303    

DOI:10.2175/WER.65.7.1

出版商:Water Environment Research Foundation (WERF)    

年代:1993

数据来源: WILEY

摘要:

ABSTRACT:
A pilot‐scale treatability study was performed to evaluate the capability to effectively co‐treat pumped groundwaters from industrial sites with municipal wastewaters at publicly owned treatment works (POTWs) employing activated sludge treatment. Chemicals given focused attention included selected phenolic, polycyclic aromatic hydrocarbon (PAH), and volatile aromatic compounds. The study involved the simultaneous operation of three pilot‐scale activated sludge reactors. One reactor was fed 100% municipal wastewater (control), a second was fed a 5% by flow volume site groundwater with a relatively low organic concentration, and a third was fed a 20% by flow volume site groundwater with a higher organic concentration. Monitoring was carried out to address, through reactor mass balance computations, chemical fate in terms of activated sludge adsorption, biodegradation, volatilization, and effluent discharge quality. The results of this study support the co‐treatment of contaminated groundwaters in POTWs employing activated sludge systems. The results show nonmeasurable effects in terms of activated sludge treatment performance, and nonsignificant effects in terms of treated effluent discharge and waste activated sludge quality. This work can be used to aid engineers and POTW authorities in evaluating the capability of activated sludge treatment systems to effectively handle and treat groundwaters containing phenolic, PAH, and volatile aromatic compounds.

ISSN:1061-4303    

DOI:10.2175/WER.65.7.2

出版商:Water Environment Research Foundation (WERF)    

年代:1993

数据来源: WILEY

摘要:

ABSTRACT:
Aerated stabilization basins (ASBs) are a common unit process for treating pulp and paper mill wastewaters in North America but are often unable to meet current requirements. One possible solution is the conversion of the existing system to a dual power level multicellular aerated lagoon. The dual power level lagoon process is a higher rate modified ASB system allowing effluent improvement, energy optimization, and total detention time reduction. To evaluate the suitability of such a system for the treatment of unbleached kraft mill effluent mixed with a municipal wastewater, industrial scale pilot plant tests were conducted over a period of 9 months. The BOD removal kinetics and the ability of the system to reduce effluent toxicity were evaluated for several operating conditions.
The dual power level multicellular lagoon process was able to produce effluent nontoxic to rainbow trout,Daphnia magna,and photoluminescent bacteria, despite a median lethal concentration of the untreated effluent in the range of 18 to 24% (96 h LC 50). This effluent also met the requirements for BOD and suspended solids. The treated effluent was analyzed for several nonconventional pollutants (including toluene, styrene, phenolic compounds, and surfactants) and some extractable organic compounds. In general, few contaminants showed concentrations above analytical detection limit levels. Those that did have positive values were generally present in concentrations less than 1 μg/L. The observed concentrations were consistent with a joint U.S. EPA and Ontario Forest Industry Association screening study of pulp and paper mill effluents. The concentrations were close to analytical detection limits.

ISSN:1061-4303    

DOI:10.2175/WER.65.7.3

出版商:Water Environment Research Foundation (WERF)    

年代:1993

数据来源: WILEY

摘要:

ABSTRACT:
A rational framework for selecting the least‐cost treatment technology for aqueous organic wastes was developed by using performance and cost models. The following three treatment options were evaluated for 15 different chemicals in this research: packed tower air stripping, packed tower air stripping followed by gas‐phase adsorption (granular activated carbon) of off‐gases, and liquid‐phase adsorption (granular activated carbon). The least‐cost air stripping tower design was found to change when off‐gas treatment was added. Air stripping without off‐gas treatment was determined to be less expensive than liquid‐phase adsorption in nearly every case. A methodology was created for comparing the relative costs of liquid‐phase adsorption and air stripping with gas‐phase adsorption. The comparison methodology is based upon physical parameters of the target chemical: Henry's constant and the solute distribution parameter. The result is a diagram for rapid identification of cases for which one treatment option is significantly less expensive than the other.

ISSN:1061-4303    

DOI:10.2175/WER.65.7.4

出版商:Water Environment Research Foundation (WERF)    

年代:1993

数据来源: WILEY

摘要:

ABSTRACT:
The treatment of silica sand contaminated with pentachlorophenol (PCP) using the standard Fenton's reagent procedure, sequential addition of iron (II) and H2O2, and a goethite (α‐FeOOH)‐H2O2system was investigated. The standard Fenton's procedure oxidized 10 mg/L soluble PCP, but was ineffective in degrading 10 mg/kg or 250 mg/kg particulate and sorbed PCP in silica sand. Sequential addition of excess reagents (480 mg/L iron (II) and 7% H2O2) degraded particulate and sorbed PCP, but with high stoichiometric H2O2requirements. The most efficient system for PCP degradation was the H2O2‐goethite system. Although the experimental system used in this research lacks the complexity of natural soils, the data suggest that under proper conditions, the iron oxyhydroxide fractions of the soil matrix catalyze Fenton‐like reactions, and that these mineral‐catalyzed reactions may be the most efficient mechanism for the catalyzed hydrogen peroxide treatment of contaminated soils.

ISSN:1061-4303    

DOI:10.2175/WER.65.7.5

出版商:Water Environment Research Foundation (WERF)    

年代:1993

数据来源: WILEY

摘要:

ABSTRACT:
Measurements of the rate of biodegradation of crude oil in seawater in laboratory, mesocosm, and field systems from 16 published reports were reviewed and compared. Volumetric biodegradation rates range widely from approximately 0.01 to 1 000 gC/m3‐d. Laboratory studies report rates at the higher end of this range, while field and mesocosm studies, of which there are fewer, suggest much lower rates ranging from 0.01 to 0.3 gC/m3‐d. Possible explanations for the discrepancy between measurements made at different scales are differences in oil concentration and in mixing energy. When temperature‐scaled degradation rates from all systems are plotted versus initial oil concentration on a log‐log scale, the data are approximately linear (r2= 0.86) over several orders of magnitude. The slope of the regressed line is near 1, indicating that the process can be interpreted as first order with respect to oil concentration. The half‐life for biodegradation is estimated to be approximately two months at 20°C. This analysis suggests that crude oil biodegradation in seawater is relatively slow and indicates that further research is required to bridge the gap between laboratory and field systems.

ISSN:1061-4303    

DOI:10.2175/WER.65.7.6

出版商:Water Environment Research Foundation (WERF)    

年代:1993

数据来源: WILEY

摘要:

ABSTRACT:
A three‐facility, full‐scale pilot program was undertaken at three small wastewater treatment plants in British Columbia, Canada. The project concludes several years of investigation and one year of plant evaluations for sludge treatment using autothermal thermophilic aerobic digestion (ATAD). Process effectiveness was shown by demonstration of pasteurization, stabilization, and odor acceptability. Control parameters were accessed by use of oxidation reduction potential (ORP), temperature, pH, air flow rates, and energy use. Dewaterability was also studied. The studies concluded that the ATAD process was suitable for use in small communities. The information presented is taken from the final project report and is supplemented with design suggestions for use when considering the ATAD process.

ISSN:1061-4303    

DOI:10.2175/WER.65.7.7

出版商:Water Environment Research Foundation (WERF)    

年代:1993

数据来源: WILEY

摘要:

ABSTRACT:
The conventional biochemical oxygen demand (BOD) test requires a series of sample dilutions and can be very time‐consuming to perform. Although newer oxygen utilization tests based on pressure changes in sealed devices do not require dilutions, they are too expensive to use routinely for wastewater samples. A rapid and inexpensive test is proposed for determining oxygen demand. This procedure, called the headspace biochemical oxygen demand (HBOD) test, uses non‐diluted wastewater samples, because additional oxygen from the container headspace is available to the microorganisms. The total oxygen demand is calculated from oxygen depleted from both the liquid and the air phases in the sealed container. Using samples from 3 wastewater treatment plants, it is shown that the HBOD test, if conducted over a 5‐day period, provides similar results to the BOD test. The three main advantages of the HBOD test are that the test can be performed more easily than the BOD test because no sample dilutions are necessary, the oxygen demand determined within a shorter period of time (24–36 h) can provide an accurate prediction of the 5‐day value, and the experimental conditions used in the HBOD test more accurately reproduce the hydrodynamic and culture conditions typical of wastewater treatment bioreactors. These advantages make the HBOD test more useful for treatment plant process evaluation and control.

ISSN:1061-4303    

DOI:10.2175/WER.65.7.8

出版商:Water Environment Research Foundation (WERF)    

年代:1993

数据来源: WILEY

摘要:

ABSTRACT:
A promising method of accelerating the removal of residual DNAPLs from aquifers involves the mobilization of trapped globules by alcohol flooding. This technology was originally developed in the petroleum industry for the recovery of residual oil after waterflooding. Alcohols can significantly reduce the interfacial tension between the residual DNAPLs and the aqueous phase, allowing for mobilization of trapped globules through pore constrictions. In addition, laboratory batch and column results show that certain alcohols preferentially partition into the DNAPL phase, swelling the residual DNAPL globules considerably and at the same time reducing their density significantly. The swollen DNAPL globules become a relatively continuous phase during flooding, making them much easier to displace than disconnected residuals. Density reduction makes the mobilized DNAPL easier to control, and reduces the potential for further downward migration into uncontaminated portions of the aquifer. Laboratory column results confirm that residual trichloroethylene and tetrachloroethylene globules can be effectively removed from glass bead packings at low upflow gradients using preferentially DNAPL‐soluble alcohols.

ISSN:1061-4303    

DOI:10.2175/WER.65.7.9

出版商:Water Environment Research Foundation (WERF)    

年代:1993

数据来源: WILEY

摘要:

ABSTRACT:
Wastewater solids were added to a series of marine mesocosms at the Marine Ecosystem Research Laboratory (MERL), University of Rhode Island. There was a range of sludge addition simulating 1, 4, and 8 times the average nitrogen enrichment of Narragansett Bay. Three other mesocosms received inorganic nutrients at similar levels, and three mesocosms were maintained as controls. In systems receiving nutrients or sludge, primary production was initially increased. Respiration of the increased loading in the sludge treatment generally resulted in decreased dissolved oxygen concentrations. In the highest level of sludge treatment, the benthic respiration resulted in anoxic conditions in the fourth month of the experiment. The benthos seemed to be the area primarily affected by wastewater disposal. Species feeding at or near the sediment–water interface showed a strong positive density response to sludge addition because of the increase in available food. Based on the findings of this experiment and comparison with marine areas of wastewater disposal, the condition of the benthic community can be generally defined based on organic loading rates. Organic loading rates less than approximately 0.1 g/m2· d C had little effect on the sediment community. Loading rates between 0.1 and 1.0 g/m2· d C resulted in an enriched sediment community, while loading over 1.5 g/m2· d C produced degraded conditions. The quantification of the relationship between organic loading and benthic response presented here can be useful in evaluating wastewater treatment and disposal options.

ISSN:1061-4303    

DOI:10.2175/WER.65.7.10

出版商:Water Environment Research Foundation (WERF)    

年代:1993

数据来源: WILEY