The effects of 1-decyl-3-methylimidazolium bromide on activated sludge process and microbial composition were investigated. Ionic liquid (IL) was dosed continuously to the laboratory activated sludge system at an influent concentration from 1 to 20 mg l−1 for about 1 month. As compared to the control test, mean values of degree of chemical oxygen demand removal and degree of biochemical oxygen demand removal were almost remaining constant at a high level, equaling 92.6% and 98.1%, respectively. In addition, no influence of IL on size and shape of flocs was observed. The values of the sludge biotic index indicate that sludge exposed on IL was stable and very well colonized with good biological activity. Increases in Proteobacteria (mainly Variovorax sp., Vogesella sp., Hydrogenophaga sp.), Bacteroidetes (mainly Lewinella sp., Haliscomenobacter sp., Runella sp.) and Nitrospirae were detected in sludge adapted to IL compared to the control system. The results showed that activated sludge can adapt to IL present in wastewater.
Storage of cattle slurry leads to emissions of methane (CH4), nitrous oxide (N2O), ammonia (NH3), and carbon dioxide (CO2). On dairy farms, winter is the most critical period in terms of slurry storage due to cattle housing and slurry field application prohibition. Slurry treatment by separation results in reduced slurry dry matter content and has considerable potential to reduce gaseous emissions. Therefore, the efficiency of slurry separation in reducing gaseous emissions during winter storage was investigated...
ABSTRACTAerobic, anoxic, and anaerobic selectors have become popular for controlling filamentous bulking in activated sludge systems; however, selectors are not always successful. Regression analyses of data collected from 44 full-scale wastewater treatment plants, with operating selectors, provided criteria for determining when selectors will and will not be successful. Anoxic selectors do not appear to control filamentous bulking in long-mean cell residence time (MCRT) plants. Further, the elimination of all...
An anaerobic sequencing batch reactor (ASBR) was operated to study the effects of tylosin, a macrolide antimicrobial commonly used in swine production, on treatment performance and the development of antimicrobial resistance. The addition of 1 mg/l tylosin to the reactor had no effects on the biogas production and chemical oxygen demand (COD) removal efficiency. Specific methanogenic activity (SMA) batch tests showed a significant (p < 0.05) decrease of the maximum methane production rate in the presence of...
In constructed wetlands (CWs) with horizontal sub-surface flow, nutrient removal, especially phosphorus, is limited because the root biomass fills the pore spaces of the substrate (usually gravel), directing wastewater flow to deeper wetland media, plants are not regularly harvested, the litter formed by decomposing vegetation remains on the surface of the substrate and thus does not interact with the wastewater, and the substrate media often used provide only limited adsorption. Effective nutrient removal...
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Overview
Since 1994, the
Schick company of Milford has systematically eliminated the use of conditioning
chemicals in its cooling tower water by installing commercially available electrically
powered water conditioning units. The company now operates all its cooling towers
without the use of conditioning chemicals. This has dramatically reduced conditioning
chemical costs, associated management costs and regulatory burdens. These changes
have resulted in a...
The OUR Set-Point method is useful for controlling the activity and loading-rate capacity of an activated sludge mixed liquor. In this case, sufficient amounts of a stock substrate are added to a mixed liquor suspension to provide kinetic saturation with subsequent measure of OUR. Once an acceptable substrate is found for a specific wastewater treatment plant, an OUR can be identified that provides acceptable performance. This OUR is identified as the `Set-Point OUR. The operator then maintains a constant OUR by...
The Kemwater Recycling Process – KREPRO for treatment of sewage sludge is based on a completely new separation technology, which uses existing knowledge in an innovative way. It reduces both the organic and inorganic content of the sludge. The organic content is re-duced by about 30% and the inorganic about 70% if digested sludge is treated. All metals and salts are dissolved; the remaining undissolved inorganics are mainly silicates like sand and grit.
In constast, most sludge treatment technologies used today...
Introduction
There is considerable public, scientific and regulatory concern over the possible adverse health effects of chronic exposure to trace levels of persistent organic pollutants. The class of compounds made up of the polychlorinated dibenzo-p-dioxins (PCDD) and polychlorinated dibenzofurans (PCDF), often collectively known as dioxins, has received widespread attention and attracted a great deal of research, following the accidental release of the most toxic of these (2,3,7,8 TCDD) at Seveso in 1976.
Diox...
The largest composter in the state of Washington, Cedar Grove Compost Company in Seattle, had its hands full of challenges in 1997 — confronted with a half million dollar fine, a lawsuit, and angry neighbors. With the adoption of an Environmental Management System (EMS), the compost facility has turned its precarious situation around and stayed in business, while dramatically cutting odor problems. With a generally satisfactory full year under its belt, the composter is looking forward to even better results in...
The treatment of industrial effluent from the paper manufacturing facilities in British Columbia is a major concern because the effluent is discharged into prime salmon habitat in the marine environment (Cross, 1994). High levels of biological oxygen demand (BOD) in the effluent reduce the dissolved oxygen (DO) available to species in the marine environment. In 1988, the Federal Department of Fisheries and Oceans reviewed the levels of DO and total suspended solids (TSS) that are discharged in the effluent...
The use of compost in various environmental applications is one of the most intensive areas of compost research being pursued today. The high organic matter content and biological activity of compost makes it effective for use in a variety of applications. Five of these will be reviewed in this article: erosion control, revegetation, biofiltration, bioremediation, and wetlands construction.
EROSION CONTROL
Erosion control is a relatively new and promising application for compost. Research has shown that...
Steel Castings Pty Ltd installed a computerised ‘Autocat’ system to control the addition of catalyst and binder for the production of sand moulds. The finer control of addition rates has significantly reduced the number of reject moulds and achieved annual savings of $21,780 from reduced raw sand and chemical costs.
Background
Steel Castings Pty Ltd operates a foundry located in Port Melbourne, Victoria. The foundry produces high integrity steel, alloy and stainless castings from 50 kg to 3,800 kg in size. It...
There has been a sharply falling trend in the total volume of sales of agricultural pesticides in the EU between 1991 and 1995. But this was reversed in 1996. From 1991-1995, EU sales of pesticides, measured by weight of active ingredients (ai), fell by 13%. They then rose by 6% between 1995 and 1996 to stand at 299,826 tonnes ai. But this still put them nearly 8% below the 1991 figure. The use of lower-dose pesticides has been a key contributor to the fall in weight of active ingredients sold in recent years....
` In order to determine the effectiveness of actions to improve environmental quality it is necessary to be able to measure relevant environmental parameters at a level of detail which is accurate enough to distinguish the anticipated changes. However, the establishment and maintenance of monitoring systems is time-consuming and expensive and therefore the scale of such systems needs to be kept to a realistic minimum and the greatest possible use made of data collected. Experience with monitoring systems in World...
Introduction
The utilization of fungal biodegradation involves the controlled usage of these specially cultivated fungi to treat contaminants.
White Rot Fungus
White rot fungus has been reported to degrade a wide variety of organopollutants because of its lignin-degrading or wood-rotting enzymes. Two different treatment configurations have been tested for white rot fungus, in situ and bioreactor. An aerobic system using moisturized air on wood chips is used in a reactor for biodegradation. A reactor was used...
Site soil conditions frequently limit the selection of a treatment process. Process-limiting characteristics such as pH or moisture content may sometimes be adjusted. In other cases, a treatment technology may be eliminated based upon the soil classification (e.g., particle-size distribution) or other soil characteristics.
Soils are inherently variable in their physical and chemical characteristics. Usually the variability is much greater vertically than horizontally, resulting from the variability in the...
Recently there has been considerable concern in California about the detection of N-nitrosodimethylamine (NDMA) in drinking water at levels as high as 900 ppt. NDMA was found to be a carcinogen in animals and assessed as a Class 1 carcinogen. It is currently listed as a priority pollutant on the US EPA National Priorities List. California has set an `action level` of 20 ppt for NDMA.
NDMA is thermally stable in aqueous solutions. Conventional methods such as biological treatment, air stripping and activated...
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