Community Sewage Research Articles

Application of small community sewer system for improving the quality of the water resource in Korea

An existing SBR plant in a rural area was retrofitted from a conventional fill-and-draw system to an intermittent-aeration system for additional nitrogen removal. This study indicated that organic and nitrogen removal efficiency was improved over that before the retrofitting. But effluent phosphorus concentration was increased gradually with the operating time. In the latter period of investigation, phosphorus concentration in effluent was higher than influent. It was regarded that an excessively accumulated phosphorus was released again under the anaerobic conditions of the sludge storage tank. The application of the electro-coagulation process was investigated as an alternative method in order to prevent phosphorus from re-releasing. A laboratory test for electro-coagulation indicated that T-P removal was more stable than the biological method only. In addition, it was confirmed that T-N and organic materials as well as T-P were removed simultaneously by the electrochemical reaction in the bioreactor combined with electrolysis by more than the bioreactor only.

Cost Effective Limits of Community Sewer Systems

Cost Effective Limits of Community Sewer Systems

Morton To Pay $38 Million To Settle Environmental Charges

Morton International, a subsidiary of Rohm and Haas, will pay $22 million in penalties to settle charges that it violated air, water, and waste regulations at a Mississippi plant. It will also invest $16 million in projects to enhance the environment, including upgrading a community sewer system. The case began in 1996 when an Environmental Protection Agency inspector went to Morton's adhesives and sealants production facility in Moss Point, Miss., near the Escatawpa River. Chuck D. Barlow, general counsel for the Mississippi Department of Environmental Quality (MDEQ), tells C&EN the inspector found that numbers on wastewater discharge monitoring reports had been falsified before they were sent to regulators. The discovery prompted MDEQ, EPA, and Morton to dig deeper into the plant's compliance with environmental standards. The plant illegally handled and disposed of hazardous wastes at its on-site landfill and violated its permit for deep injection wells by pumping unauthorized wastes down those wells, ...

The effects of uncertainties on the control performance of sewer networks

The effects of uncertainties on the performance of a Certainty Equivalent Open Loop Feedback Control approach is investigated throughout simulations of the Quebec Urban Community Sewer Network. The optimization algorithm is based on nonlinear programming with the peculiarity that all the constraints are linear. The hydraulic routine is a Linear Time Invariant (LTI) model associated to a Kalman filter. Preliminary results show the benefit of adding a filtering action to guarantee robust performance in the presence of measurement errors and model mismatch. The selected control scheme seems to be a good compromise between the short computational time required for Real Time Control applications and the high performance expected in the presence of uncertainties.

PCBs and PAHs in the Montreal Urban Community (Quebec, Canada) wastewater treatment plant and in the effluent plume in the St Lawrence River

Samples of raw and treated wastewater were collected at the Montreal Urban Community (Canada) sewage treatment plant between July and October 1993 and analysed for PCBs and PAHs. Water samples were also collected in the effluent plume in the St Lawrence River during the same period. The average concentrations of Σ13 PCBs in raw wastewater and treated wastewater were 4.3 and 1.4 ng/l. respectively. For PAHs, average concentrations in raw wastewater and treated wastewater were 1.5 and 0.4 μg/l, respectively. The removal rates for PCB congeners and individual PAHs ranged from 33 to 100%. Approximately 1 kg of PCBs and 0.26 tonnes of PAHs were discharged annually by the MUC wastewater treatment plant to the St Lawrence River. Levels of PCBs and PAHs increased significantly at the effluent outfall in the river compared to those measured at the upstream site. In the effluent plume, concentrations of PCBs and PAHs reached background levels at approximately 13 and 6 km downstream from the effluent outfall, respectively.

The effects of uncertainties on the control performance of sewer networks

The effects of uncertainties on the performance of a Certainty Equivalent Open Loop Feedback Control approach is investigated throughout simulations of the Quebec Urban Community Sewer Network. The optimization algorithm is based on nonlinear programming with the peculiarity that all the constraints are linear. The hydraulic routine is a Linear Time Invariant (LTI) model associated to a Kalman filter. Preliminary results show the benefit of adding a filtering action to guarantee robust performance in the presence of measurement errors and model mismatch. The selected control scheme seems to be a good compromise between the short computational time required for Real Time Control applications and the high performance expected in the presence of uncertainties.

Aquatic toxicity emission from Tokyo: wastewater measured using marine luminescent bacterium, photobacterium phosphoreum

Aquatic toxicity of point-source discharges are examined with the MICROTOX system using luminescent bacteria, Photobacterium phosphoreum. Samples include treated wastewaters from industrial dischargers, municipal sewage treatment plants and community sewage treatment plants, all of which eventually flow into Tokyo Bay. Among 34 samples from industry, 11.7% exhibit high toxicity (EC50 =< 0.2), 17.6% exhibit low toxicity (0.2 < EC50 =< 1), and 70.7% were non- or only slightly toxic (1 < EC50). Aquatic toxicity of treated wastewater is mostly due to the chlorination process. Results suggest that 96% of the total toxicity load of all point-source discharges is caused by chlorination. The toxicity assessment with luminescent bacteria is shown to be effective and of practical use, since it facilitates the evaluation of the total toxicity which cannot be well embodied in the current regulation systems by specific indices.

Aquatic toxicity emission from tokyo: wastewater measured using marine luminescent bacterium, photobacterium phosphoreum

Aquatic toxicity of point-source discharges are examined with the MICROI system using luminescent bacteria, Photobacterium phosphoreum. Samples include treated wastewaters from industrial dischargers, municipal sewage treatment plants and community sewage treatment plants, all of which eventually flow into Tokyo Bay. Among 34 samples from industry, 11.7% exhibit high toxicity (EC5O = < 0.2), 17.6% exhibit low toxicity (0.2 < EC5O = < 1), and 70.7% were non- or only slightly toxic (1 < EC5O). Aquatic toxicity of treated wastewater is mostly due to the chlorination process. Results suggest that 96% of the total toxicity load of all point-source discharges is caused by chlorination. The toxicity assessment with luminescent bacteria is shown to be effective and of practical use, since it facilitates the evaluation of the total toxicity which cannot be well embodied in the current regulation systems by specific indices.

Seventh international symposium on individual and small community sewage systems

Seventh international symposium on individual and small community sewage systems

Direct detection of wild poliovirus circulation by stool surveys of healthy children and analysis of community wastewater.

Cartagena, Colombia, was one of the last cities in the Americas known to have endemic poliomyelitis. After 3 cases were identified in 1991, two approaches for detecting continued silent transmission of wild polioviruses within a high-risk community were used: stool surveys of healthy children and virologic analysis of community sewage. Wild type 1 polioviruses were isolated from 8% of the children studied and from 21% of sewage samples. The proportions of wild polioviruses, vaccine-related polioviruses, and nonpolio enteric viruses were similar for both approaches. Wild poliovirus sequences were also amplified directly from processed sewage samples by the polymerase chain reaction using primer pairs specific for the indigenous type 1 genotype. The last reported cases associated with wild polioviruses in the Americas occurred in Colombia (8 April 1991) and Peru (23 August 1991). Direct sampling for wild polioviruses in high-risk communities can provide further evidence that eradication of the indigenous wild polioviruses has been achieved in the Americas.

Series of Studies on Techniaues for Removing Nitrogen and Phosphorus from Community Sewage

Series of Studies on Techniaues for Removing Nitrogen and Phosphorus from Community Sewage

Circuit riding for managing small community sewage systems

Providing wastewater treatment services for small communities can be expensive, so many communities have chosen part-time or inadequately trained operators. This can result in neglect and poor plant performance. Indiana County, Pennsylvania, in the USA, has established an authority to provide operation and maintenance through a circuit riding arrangement. Two operators travel to eight plants five days a week. This has resulted in more consistent operation and maintenance at affordable rates. Homeowners pay $12.60–$18.00 and commercial customers pay $25–$150 a month. Even with regular attention, these small plants are not able to meet their effluent requirements at all times.

Performance of Sequencing Batch Reactor Activated Sludge Processes for Simultaneous Removal of Nitrogen, Phosphorus and Bod as Applied to Small Community Sewage Treatment

Laboratory-scale sequencing batch reactor (SBR) activated sludge process was fed with synthetic wastewater to clarify the possibility of simultaneous removal of nitrogen, phosphorus, and organic substances by modifying operational schedule. Anoxic and/or anaerobic reactions in addition to aerobic reactions were introduced into a cycle of batch operation. Simultaneous removal of nitrogen, phosphorus and organic carbon was shown to be possible by the modified operation of SBR into which reactions without aeration (anoxic/anaerobic) were introduced during the fill period. Oxidized nitrogen remaining in the reactor at the end of the former cycle was removed by denitrification during the fill. Anaerobic conditions after the denitrification was completed enhanced phosphorus release from the sludge and the following luxury uptake during aeration removed phosphorus from water. Both extension and reduction of anoxic/anaerobic period in the beginning of a cycle damaged phosphorus removal and sludge settlability. Thus, an optimum length of period for these reactions must be chosen for successful operations. The best length of this period coincided with that of the fill within the range of this study.

Application of a Nonparametric Approach for Monitoring and Detecting Trends in Water Quality Data for the St

Abstract To overcome some of the restrictions due to the irregular structure of water quality data, a nonparametric approach has been developed based on Kendall’s T and a seasonal adjustment model, which enables one to test for the significance of trends as well as to monitor the trend variations with time. This methodology has been applied to water quality data for the St. Lawrence river obtained from Environment Canada and the municipality of Varennes. The results from the first source indicate that a positive trend is developing for conductivity and pH downstream from the Island of Montreal, whereas upstream from the Island pH is the only parameter indicating a positive trend. Data from the municipality of Varennes, due to their excellent quality, were used to verify the validity of the previous results as well as the reliability of the applied methodology. Analysis of the Varennes data with a parametric method indicated that a positive trend in pH is indeed evident. This finding will be of consequence for future studies to ascertain the effect on the river of the new Montreal Urban Community Sewage Treatment Plant.

Use of Moore swabs for isolating Vibrio cholerae from sewage.

The Moore swab method was shown to be a practical and sensitive technique for the isolation of Vibrio cholerae from sewage. In each of three instances in which cholera patients lived in homes connected to municipal sewers, V. cholerae was isolated from the community sewage plant intake at the time of the patients illness. Sewer systems became negative within 1 day after patients were treated with tetracycline. Sewer surveillance using the Moore swab also found evidence of infections occurring in areas where surveillance of diarrheal illness failed to detect cholera. Culturing community sewage by the Moore swab method proved to be an economical and effective way of determining areas where V. cholerae infections were occurring.

Judgmental Bias in the Rating of Attitude Statements

Judges holding divergent attitudes toward high contact uses of water reclaimed from community sewage rated two sets of attitude statements regarding this issue. Results showed a close linear relationship between item scale values obtained from positive and negative attitudinal groups, and also a somewhat reduced range of ratings for judges holding unfavorable personal attitudes toward reuse. These findings, and the findings of previous research on this issue, were seen as being consonant with an item displacement theory of rating performance and supportive of equal interval measurement.