The fate of detergent surfactants in sewer systems

1995 ◽  
Vol 31 (7) ◽  
pp. 321-328 ◽  
Author(s):  
E. Matthijs ◽  
G. Debaere ◽  
N. Itrich ◽  
P. Masscheleyn ◽  
A. Rottiers ◽  
...  
Keyword(s):  
Fatty Alcohol ◽  
Half Life ◽  
Laboratory Tests ◽  
Field Experiments ◽  
Sewage Treatment ◽  
Field Studies ◽  
Municipal Sewage ◽  
Alcohol Ethoxylate ◽  
Rapid Reduction ◽  
Laboratory Findings

The fate of detergent surfactants in the sewer can be studied both in laboratory tests and in field experiments. The laboratory studies can be used to determine the rate of disappearance of a test molecule as a function of residence time and estimate its half-life in a given habitat. In addition, important information can be obtained on the mechanism of degradation. Field studies can determine the actual environmental concentrations of surfactants in raw sewage which can then be compared with the expected concentration based on consumption volumes. The difference between the measured and predicted concentration provides an estimate for the disappearance of the test chemical during its travel in the sewer and confirms the results of the laboratory tests. This paper focuses on the fate of a number of important representative anionic, nonionic and cationic surfactants, in the sewer. The results of laboratory die-away studies showed that, in general, the half-life for disappearance in the sewer was in the order of hours for Fatty Alcohol Ethoxylate (AE), Fatty Alcohol Ethoxy Sulphate (AES) and Di-Ethyl-Ester Di-methyl-Ammonium Chloride (DEEDMAC). These laboratory findings for AES were confirmed by monitoring actual raw sewage reaching municipal sewage treatment plants. In addition, a field study demonstrated that the concentration of glucose amides (GA) is considerably reduced during its travel in the sewer. These complementary laboratory and field studies provide key information for the safety assessment of surfactants. They demonstrate that the concentration of surfactants can be significantly reduced in the sewer resulting in a rapid reduction of the environmental loading, which is particularly important in environmental situations where inadequate or no sewage treatment exists.

SCREENING OF CHEMICAL SPILL RISKS TO MUNICIPAL SEWAGE TREA TMENT PLANTS

1994 ◽  
Vol 30 (4) ◽  
pp. 25-34
Author(s):  
M. Ettala ◽  
E. Rossi
Keyword(s):  
Wastewater Treatment ◽  
Wastewater Treatment Plants ◽  
Sewage Treatment ◽  
Screening Method ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Chemical Properties ◽  
Carbonaceous Material ◽  
Field Studies ◽  
Municipal Sewage

Seven operational mishaps were specified on the basis of a questionnaire on wastewater treatment plants, some of them large. In this study a process was developed for screening the chemical spill risks to municipal biological sewage treatment plant. Data on wastewater treatment processes, potential spill sources and chemical properties were combined to determine the threshold chemical quantities which may inhibit the removal of carbonaceous material, prevent nitrification and methanogenesis, cause sludge contamination or lead to the aeration capacity being exceeded. Two sewage treatment plants and eleven industrial sites were chosen for field studies. The influence of spill duration and maintenance activities on threshold quantities are discussed. A field survey lasting 1-2 hours at each site was long enough for the most relevant data to be obtained when the screening method developed was applied. Several chemical spill risks to the plants studied were specified. In addition, cases were identified in which failure of the pretreatment facilities for industrial wastewaters could cause severe mishaps at a biological wastewater treatment plant.

scholarly journals Technology for Upgrading the Tailwater of Municipal Sewage Treatment Plants: The Efficacy and Mechanism of Microbial Coupling for Nitrogen and Carbon Removal

Water ◽  
2021 ◽  
Vol 13 (20) ◽  
pp. 2850
Author(s):  
Yinan Zhang ◽  
Shihuan Lu ◽  
Yuxin Fang ◽  
Kexin Yang ◽  
Jiafeng Ding ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Removal Efficiency ◽  
Municipal Wastewater ◽  
Field Experiments ◽  
Wastewater Treatment Plants ◽  
Sewage Treatment ◽  
Treatment Plant ◽  
Municipal Sewage ◽  
Municipal Wastewater Treatment ◽  
Carbon Removal

The efficient removal of carbon (COD) and nitrogen (NH3-N) is vital to improving tailwater from municipal wastewater treatment plants. In this study, denitrification and decarburization bacteria with stable removal efficiencies were introduced into a membrane bioreactor (MBR) for 45 days of field experiments in a QJ Wastewater Treatment Plant (Hangzhou, China) to enhance carbon and nitrogen removal. After adding the decarbonization microorganisms into the denitrification reactor, COD removal increased from 31.2% to 80.2%, while compared to the same MBR with only denitrification microorganisms, the removal efficiency of NH3-N was greatly increased from 76.8% to 98.6%. The results of microbial analysis showed that the cooccurrence of Proteobacteria and Bacillus with high abundance and diverse bacteria, such as Chloroflexi, with autotrophic decarburization functions might account for the synchronous high removal efficiency for NH3-N and COD. This technology could provide a reference for industrial-scale wastewater treatment with the goal of simultaneous nitrogen and carbon removal.

Influence of planting date on plant losses and yield responses of geranium (Pelargonium graveolens) to root rot and wilt

1992 ◽  
Vol 118 (3) ◽  
pp. 309-314 ◽  
Author(s):  
A. Kalra ◽  
T. N. Parameswaran ◽  
N. S. Ravindra
Keyword(s):  
Root Rot ◽  
Laboratory Tests ◽  
Field Experiments ◽  
Field Studies ◽  
Planting Date ◽  
Higher Plant ◽  
Pelargonium Graveolens ◽  
Lower Survival Rate ◽  
Pot Experiments ◽  
Yield Responses

SUMMARYDifferent geranium (Pelargonium graveolens L. Herit) clones differed in susceptibility to root rot and wilt caused by Rhizoctonia solani Kuhn. Reactions were consistent when assessed either by standardized laboratory tests or by pot experiments using 60-day-old well-rooted plants. Plants of an Algerian-type clone (Kd) had a lower survival rate and higher root rot index values than those of a Reunion type (Lo) and an Egyptian type (Eg). Field studies conducted in naturally-infected plots in southern India from 1987 to 1990 showed that summer planting resulted in higher plant losses of all clones than winter planting. As in the laboratory and pot experiments, the Lo and Eg clones sustained less plant loss and produced higher herbage and oil yields than the Kd clones in both field experiments.

Presence of Phenolic Compounds in Sewage, Effluent and Sludge from Municipal Sewage Treatment Plants

1982 ◽  
Vol 14 (4-5) ◽  
pp. 143-150 ◽  
Author(s):  
F B DeWalle ◽  
D A Kalman ◽  
R Dills ◽  
D Norman ◽  
E S K Chian ◽  
...  
Keyword(s):  
Sewage Treatment ◽  
Municipal Sewage ◽  
Sewage Effluent ◽  
Capillary Gc ◽  
Digested Sludge ◽  
Calculated Concentration ◽  
Sewage Treatment Plants ◽  
Anaerobically Digested Sludge ◽  
Final Effluent ◽  
Dimethyl Phenol

A total of 25 municipal sewage treatment plants were sampled, 10 of which were resampled, to determine the quantity of phenolics in the sewage, final effluent and the anaerobically digested sludge using capillary GC/MS/DS/techniques. The study noted in decreasing order of frequency in raw sewage: phenol, pentachloro-phenol, dimethyl phenol, 3-methyl, 4-chlorophenol, 2,4,6-trichloro-phenol, 2,4-dichlorophenol, 2-nitrophenol, 2-chlorophenol, 2,4-dinitro-6-methylphenol and 2,4-dinitrophenol. The maximum concentration of phenol in sewage and sludge was 2800 ppb and 4460 respectively, while similar values for pentachlorophenol were 58 and 1200 ppb. Statistically calculated concentration reductions for phenol and dimethyl phenol were generally greater than noted for tri- and pentachlorophenol. Low decreases or increases were noted for monochlorophenol and especially for dichlorophenol as a result of the chloronation of the final effluent.

The Possible Utilization of Waste Sludge as an Adsorbent for Removal of Organic Vapor

1986 ◽  
Vol 18 (7-8) ◽  
pp. 413-420 ◽  
Author(s):  
P. C. Chiang ◽  
J. H. You
Keyword(s):  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Municipal Sewage ◽  
Methyl Ethyl ◽  
Organic Vapor ◽  
Waste Sludge ◽  
Catalyst Temperature ◽  
Major Factors ◽  
Municipal Sewage Treatment Plant

In this investigation it was found that the waste sludge obtained from a municipal sewage treatment plant could be reclaimed as an adsorbent for removal of organic vapours, i.e. toluene, methyl-ethyl-ketone and 1-1-2-trichloroethylene, through use of a pyrolysis technique. In order to find the optimum manufacturing process, several tests were performed under various conditions in which the addition of a catalyst, temperature control, and residence time in the furnace, were considered as the three major factors. Both the reclaimed adsorbent and commercially available activated carbon were evaluated to determine their adsorption capacity at various influent concentrations of organic vapours.

Behaviour of Alkylphenol Polyethoxylate Surfactants and of Nitrilotriacetate in Sewage Treatment

1987 ◽  
Vol 19 (3-4) ◽  
pp. 449-460 ◽  
Author(s):  
W. Giger ◽  
M. Ahel ◽  
M. Koch ◽  
H. U. Laubscher ◽  
C. Schaffner ◽  
...  
Keyword(s):  
Activated Sludge ◽  
Sewage Treatment ◽  
Operating Conditions ◽  
Municipal Sewage ◽  
Sludge Treatment ◽  
Loading Rates ◽  
Treatment Conditions ◽  
Physico Chemical ◽  
Treated Sewage ◽  
Removal Efficiencies

Effluents and sludges from several municipal sewage treatment plants in Switzerland were analyzed for nonylphenol polyethoxylates (NPnEO, n=3-20), nonylphenol mono- and diethoxylate (NPlEO, NP2EO), corresponding nonylphenoxy carboxylic acids (NP1EC, NP2EC) and nonylphenol (NP). These chemicals derive from nonionic surfactants of the NPnEO-type, and specific analitical techniques were used to study their behaviour during mechanical-biological sewage and subsequent sludge treatment. The parent NPnEO-surfactants, with concentrations in raw and mechanically treated sewage from 400-2200 mg/m3, were relatively efficiently removed by the activated sludge treatment. The abundances of the different metabolites varied depending on treatment conditions. The refractory nature of NPl/2EO, NP and NPl/2EC was recognized. Both biotransformations and physico-chemical processes determine the behaviour and fate of nonylphenolic substances in sewage treatment. Nitrilotriacetate (NTA) was found in primary effluents at concentrations between 430 and 1390 mg/m3. The various treatment plants showed different removal efficiencies for NTA depending on the operating conditions. Activated sludge treatment with low sludge loading rates and nitrifying conditions removed NTA with efficiencies between 95 and 99%. High sludge loading caused a decrease in NTA removal efficiencies from 70% to 39%.

Oxygen transfer in gravity flow sewers

1995 ◽  
Vol 31 (7) ◽  
pp. 127-135 ◽  
Author(s):  
P. Balmér ◽  
M. Tagizadeh-Nasser
Keyword(s):  
Energy Dissipation ◽  
Oxygen Transfer ◽  
Laboratory Tests ◽  
Field Studies ◽  
Gravity Flow ◽  
Clean Water

Oxygen transfer to water in gravity flow pipes has been studied in a 24 m long, 0.225 m diameter sewer. Laboratory tests were conducted where the slope and flow in the sewer could be varied independently. The clean water reaeration test was used to determine the oxygen transfer. The KL value for the oxygen transfer was found to be a function of energy dissipation and mean hydraulic depth. The results are discussed in relation to oxygen transfer determinations in flumes and field studies of oxygen transfer in sewers.

scholarly journals Evaluating the Impact of Two Generalist Predators on the Leafhopper Erasmoneura vulnerata Population Density

Insects ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 321
Author(s):  
Stefan Cristian Prazaru ◽  
Giulia Zanettin ◽  
Alberto Pozzebon ◽  
Paola Tirello ◽  
Francesco Toffoletto ◽  
...  
Keyword(s):  
Field Experiments ◽  
Field Studies ◽  
Generalist Predators ◽  
Predator Species ◽  
Potted Plants ◽  
Naturally Occurring ◽  
Orius Majusculus ◽  
Limited Effectiveness ◽  
Pest Outbreaks ◽  
The Impact

Outbreaks of the Nearctic leafhopper Erasmoneura vulnerata represent a threat to vinegrowers in Southern Europe, in particular in North-eastern Italy. The pest outbreaks are frequent in organic vineyards because insecticides labeled for organic viticulture show limited effectiveness towards leafhoppers. On the other hand, the naturally occurring predators and parasitoids of E. vulnerata in vineyards are often not able to keep leafhopper densities at acceptable levels for vine-growers. In this study, we evaluated the potential of two generalist, commercially available predators, Chrysoperla carnea and Orius majusculus, in suppressing E. vulnerata. Laboratory and semi-field experiments were carried out to evaluate both species’ predation capacity on E. vulnerata nymphs. The experiments were conducted on grapevine leaves inside Petri dishes (laboratory) and on potted and caged grapevines (semi-field); in both experiments, the leaves or potted plants were infested with E. vulnerata nymphs prior to predator releases. Both predator species exhibited a remarkable voracity and significantly reduced leafhopper densities in laboratory and semi-field experiments. Therefore, field studies were carried out over two growing seasons in two vineyards. We released 4 O. majusculus adults and 30 C. carnea larvae per m2 of canopy. Predator releases in vineyards reduced leafhopper densities by about 30% compared to the control plots. Results obtained in this study showed that the two predators have a potential to suppress the pest density, but more research is required to define appropriate predator–prey release ratios and release timing. Studies on intraguild interactions and competition with naturally occurring predators are also suggested.

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