Effects of Various Sewage Sludge Treatment Processes on the Survival of Potato Cyst-Nematodes (Globodera spp.) and the Implications for Disposal

1989 ◽  
Vol 21 (8-9) ◽  
pp. 909-916
Author(s):  
A. M. Spaull ◽  
D. M. McCormack ◽  
E. B. Pike

Samples of sewage sludges, taken over a 12-month period from 9 Scottish sewage works, contained on average 0.24 cysts of Globodera spp. (potato cyst-nematodes) of which 11% were viable. The incidence was not significantly related to season or to the presence of vegetable-processing effluent. Exposure of cysts in sludge to mesophilic anaerobic digestion (35 °C, 30 min) cold anaerobic digestion (9 weeks), pasteurisation (70 °C, 30 min) and aerobic thermophilic digestion (60 °C, ld) reduced viability of eggs within the cysts by almost 100%. Sludges so treated can therefore be considered to be free from infection risk to potato crops, although the non-infective cysts may still be recovered. Treatment with lime at pH 11.5 (20 °C, 24 h), by aerobic stabilisation in an oxidation ditch (7 weeks) and by activated-sludge treatment (5d) did not reduced viability acceptably. Accelerated cold digestion did not reduce viability sufficiently after the usual 15 weeks but rendered eggs completely non-viable after 21 weeks. The results show that even sludge treated to destroy viable cysts should not be applied to land used for growing seed potatoes and subject to testing for freedom from infestation. Treatment destroying viability should increase the acceptability of sludge for ware potato growers, although the numbers of cysts applied in untreated sludge would be unlikely to increase significantly levels of cysts in soils already infested.

2010 ◽  
Vol 61 (2) ◽  
pp. 365-373 ◽  
Author(s):  
S. Soda ◽  
Y. Iwai ◽  
K. Sei ◽  
Y. Shimod ◽  
M. Ike

An energy consumption model was developed for evaluating sewage sludge treatment plants (SSTPs) incorporating various treatment processes such as thickening, anaerobic digestion, dewatering, incineration, and melting. Based on data analyses from SSTPs in Osaka, Japan, electricity consumption intensities for thickening, anaerobic digestion, dewatering, incineration, and melting and heat consumption intensities for anaerobic digestion, incineration, and melting were expressed as functions of sludge-loading on each unit process. The model was applied for predicting the energy consumption and greenhouse gas (GHG) emissions of SSTPs using various treatment processes and power and heat generation processes using digestion gas. Results showed that SSTPs lacking incineration and melting processes but having power generation processes showed excess energy production at the high sludge-loading rate. Energy consumption of the SSTPs without incineration and melting processes were low, but their GHG emissions were high because of CH4 and N2O emissions from sludge cake at the landfill site. Incineration and melting processes consume much energy, but have lower CH4 and N2O emissions.


RSC Advances ◽  
2020 ◽  
Vol 10 (59) ◽  
pp. 35718-35728
Author(s):  
Reza Barati rashvanlou ◽  
Abbas Rezaee ◽  
Mahdi Farzadkia ◽  
Mitra Gholami ◽  
Majid Kermani

Micro-aeration as a pretreatment method improves the efficiency of anaerobic digestion of municipal sewage sludge and consequently promotes the methane production.


2006 ◽  
Vol 53 (11) ◽  
pp. 221-226 ◽  
Author(s):  
M. Minamiyama ◽  
S. Ochi ◽  
Y. Suzuki

Many environmental problems caused by endocrine disruptors (EDs) have been reported. It is reported that EDs flow into sewage treatment plants, and it has been pointed out that these may be shifted from the wastewater treatment process to the sludge treatment process. Little is known about the fate of EDs accumulated in sewage sludge, so we carried out a study to clarify the fate of EDs in sewage sludge treatment processes, especially in an anaerobic digestion process. In this study, nonylphenol (NP) was selected as a target ED. Nonylphenol ethoxylates (NPnEO) or nonylphenoxy acetic acids (NPnEC), which were the precursor of NP, were added to an anaerobic digestion process, and mass balance was investigated. The following results were obtained from the anaerobic digestion experiments. (1) NP1EO was injected to an anaerobic digestion testing apparatus that was operated at a retention time of approximately 28 d and a temperature of 35 °C with thickened sludge sampled from an actual wastewater treatment plant. Approximately 40% of the injected NP1EO was converted to NP. (2) NP1EC was injected to an anaerobic digestion testing apparatus with thickened sludge. As a result, almost all injected NP1EC was converted to NP. When NP2EC was injected, NP2EC was not converted to NP until the 20th day.


1986 ◽  
Vol 18 (7-8) ◽  
pp. 397-404 ◽  
Author(s):  
R. S. Reimers ◽  
D. B. McDonell ◽  
M. D. Little ◽  
D. D. Bowman ◽  
A. J. Englande ◽  
...  

In the United States, Ascaris spp., Trichuris trichiura, Trichuris vulpis and Toxocara spp. are the most commonly found viable parasites in both treated and untreated municipal sludges. As expected, heat treatment, thermophilic digestion (aerobic and anaerobic) and thermophilic composting were effective in parasite inactivation, and with good sludge digestion (both aerobic and anaerobic), the effectiveness of sludge lagoon storage and sludge drying beds to inactivate parasites and pathogens is greatly enhanced. At present two commercial sludge processes, Chemfixation and Ozonics treatment have shown potential to inactivate parasites.


Author(s):  
Satoshi Nakao ◽  
Kohsuke Akita ◽  
Asako Ozaki ◽  
Keiko Masumoto ◽  
Tetsuji Okuda

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