Bacteriological Evaluation of Composting Systems in Sludge Treatment

1999 ◽  
Vol 40 (7) ◽  
pp. 165-170 ◽  
Author(s):  
Ahmad M. Shaban
Keyword(s):  
Sewage Treatment ◽  
Faecal Coliform ◽  
Sludge Treatment ◽  
Natural Draft ◽  
Sludge Disposal ◽  
End Of Treatment ◽  
Forced Aeration ◽  
Composting Systems ◽  
Bacteriological Evaluation ◽  
Faecal Streptococci

Sludge disposal was considered as a serious problem to the authorities. Thus, the treatment of sludge resulting from sewage treatment plants to remove pathogenic microorganisms and to improve its impact on the environment was considered as the main objective of several investigators. Composting is one of the methods of sludge treatment. Different systems of composting (static pile, windrow and natural draft) were applied and evaluated bacteriologically. Faecal coliform and salmonellae were removed completely during the first two weeks in case of forced aeration, but the former are still present till near the end of experiment with natural aeration. For the natural draft system with sawdust base, faecal coliform reduction increased up to 100% after 7 weeks, while faecal streptococci and coliphage decreased gradually and were removed completely at the end of treatment. Salmonellae disappeared after a few days from starting treatment. In case of alkaloids addition (cement and lime), the tested organisms reached acceptable levels with any concentration of alkaloids. Coliphage and faecal streptococci survived till the end of treatment. So, from the previous results it is clear to say, coliphage and faecal streptococci were more resistant to the composting processes than other organisms.

Recycling to Soils: a Sustainable Way of Sludge Disposal and its Practice in China

2011 ◽  
Vol 183-185 ◽  
pp. 1417-1422 ◽  
Author(s):  
Xiang Sheng Cao ◽  
Xue Jing Meng ◽  
Xue Zheng Meng
Keyword(s):  
Sewage Treatment ◽  
Land Application ◽  
Sludge Treatment ◽  
Sewage Treatment Plants ◽  
Sludge Disposal ◽  
Successful Case ◽  
Urgent Task ◽  
Before And After ◽  
Treatment And Disposal ◽  
Disposal Problem

With the booming construction of sewage treatment plants aiming at environmental protection, China has to face an emerging urgent task to address the sludge treatment and disposal problem. However there is a big controversy in China about the sludge treatment and disposal strategies. Some scientists suggest incinerating, while others insist on landfilling. In this paper, from the perspective of sustainable development and cyclic economy, a detailed analysis of nutrients cycle mainly related to nitrogen and phosphate before and after industrialization was made and a view that sludge should go back to soils to re-establish a sound nutrients cycle was put forward. Then the feasibility for sludge recycle to soils was discussed and some land application methods for sludge were introduced. At last, a successful case of producing compounded fertilizer from dewatered sludge in Northeast China was described in detail.

Destruction of Faecal Bacteria, Enteroviruses and OVA of Parasites in Wastewater Sludge by Aerobic Thermophilic and Anaerobic Mesophilic Digestion

1991 ◽  
Vol 24 (2) ◽  
pp. 377-380 ◽  
Author(s):  
E. G. Carrington ◽  
E. B. Pike ◽  
D. Auty ◽  
R. Morris
Keyword(s):  
Sewage Treatment ◽  
Treatment Plant ◽  
Wastewater Sludge ◽  
Sludge Treatment ◽  
Volatile Solids ◽  
Working Volume ◽  
Thermotolerant Coliforms ◽  
Mesophilic Digestion ◽  
Faecal Bacteria ◽  
Faecal Streptococci

A new sludge treatment plant at Harrogate South Sewage Treatment Works is designed to handle up to 4 tonnes (dry solids) daily. Sludge is thickened continuously up to 8% (ds) and is then treated in parallel anaerobic mesophilic (AD) and thermophilic aerobic digestion (TAD) plants each with a maximum working volume of 530m3. Microbiological studies were carried out to compare the destruction of pathogens and faecal indicator bacteria. The AD plant operated with a mean retention of 26 days at 34 °C and achieved 49% reduction of volatile solids. The TAD plant operated with a mean retention of 28 days at 55 °C and reduced volatile solids by 35%. Operation was on a pump in-pump out cycle, guaranteeing 4h retention for all sludge. The disinfecting ability of TAD exceeded that of AD since it reduced counts of Enterobacteriaceae, thermotolerant coliforms and faecal streptococci to below 103/100ml, rendered cytopathic enteroviruses undetectable and destroyed viability of Ascaris suum ova within 4h. The AD process reduced bacterial counts by 90% and enteroviruses by 99%, but has no effect upon viability of Ascaris ova.

Hong Kong Sludge Treatment Facilities

2010 ◽  
Vol 5 (2) ◽  
Author(s):  
Echo Leong ◽  
Alex Kwan ◽  
Priscilla Yuen
Keyword(s):  
Hong Kong ◽  
Sewage Treatment ◽  
Treatment Technology ◽  
Sludge Treatment ◽  
Sludge Disposal ◽  
Design Build ◽  
Treatment Facilities ◽  
Dewatered Sewage Sludge ◽  
Fluidized Bed Incineration ◽  
Selection Of

At present, all dewatered sewage sludge generated by sewage treatment works (STW) is disposed of at landfills. This current practice of sludge disposal at landfill is not sustainable from both environmental and technical perspectives. The Hong Kong sludge contains high content of chloride due to use of seawater flushing in most of the Hong Kong areas and Hong Kong is a densely populated city. This unique condition has limited its selection of the alternative sludge treatment technology. The Sludge Treatment Facilities (STF) adopting fluidized bed incineration technology is a sustainable alternative for sludge disposal in Hong Kong. The design capacity of the STF is 2000 wet tonnes per day. The STF will be implemented under a Design-Build-and-Operate contract arrangement with a contractual operation period of 15 years and is scheduled to be commissioned by 2012.

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%.

Sludge Treatment and Disposal Systems for Rural Areas in Germany

1993 ◽  
Vol 27 (9) ◽  
pp. 159-171 ◽  
Author(s):  
Eberhard Steinle
Keyword(s):  
Sewage Sludge ◽  
Rural Areas ◽  
Public Awareness ◽  
Sewage Treatment ◽  
Treatment Needs ◽  
Sludge Treatment ◽  
Sewage Treatment Plants ◽  
Sewage Purification ◽  
Treatment And Disposal ◽  
Nitrogen Phosphorus

First an overview of the systems currently in use and being discussed for sludge treatment is presented will) particular emphasis on distinguishing between the object of the system (conditioning objective of the various phases in the system) and a system concept (concept of various phases of the system in sequence to attain the disposal objective). More detailed information is given as to the salient systems as used with smaller sewage treatment plants in rural areas, such as digestion, dewatering, hygienization, composting and thermal drying. A further item of discussion is how sludge treatment influences the sewage treatment process. For the critical emissions (nitrogen, phosphorus) demanded in Germany, and thus for the degree of sewage treatment required, the load of the sewage treatment system resulting from sludge treatment needs to be taken into account. Accordingly, operation of sludge treatment and sewage purification must always be harmonized. The extent of these return loads also limits the spatial centralization of the system phases; this applies in particular to smaller sewage treatment plants in rural areas. In conclusion, an attempt is made to present a perspective for the agricultural utilization of such sludge in Germany. Since the critical values for emissions have been further tightened by new regulations, thus considerably elevating the associated sophistication of monitoring techniques, it is to be expected that the use of sewage sludge in agriculture will also be further reduced in rural areas, especially since public awareness of emission control has considerably reduced the acceptance of sewage sludge as fertilizer.

Estrogenic compounds in Tunisian urban sewage treatment plant: occurrence, removal and ecotoxicological impact of sewage discharge and sludge disposal

Ecotoxicology ◽  
2016 ◽  
Vol 25 (10) ◽  
pp. 1849-1857 ◽  
Author(s):  
Dalel Belhaj ◽  
Khaled Athmouni ◽  
Bouthaina Jerbi ◽  
Monem Kallel ◽  
Habib Ayadi ◽  
...  
Keyword(s):  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Estrogenic Compounds ◽  
Sewage Discharge ◽  
Urban Sewage ◽  
Sludge Disposal

Low Cost Controlled Composting of Refuse and Sewage Sludge

1987 ◽  
Vol 19 (5-6) ◽  
pp. 839-845 ◽  
Author(s):  
J. T. Pereira-Neto ◽  
E. I. Stentiford ◽  
D. D. Mara
Keyword(s):  
Escherichia Coli ◽  
Sewage Sludge ◽  
Low Cost ◽  
Control Methods ◽  
Fixed Rate ◽  
The Past ◽  
Temperature Feedback ◽  
Forced Aeration ◽  
Domestic Refuse ◽  
Faecal Streptococci

The forced aeration static pile composting system was used to compost mixtures of domestic refuse and sewage sludge. Several different control methods have been evaluated over the past four years from simple, low cost fixed rate aeration timers to microcomputer based systems. Their relative merits are considered. In a compost pile using temperature feedback control the number of Escherichia coli were reduced from 107 org./g to less than 102 org./g. within 16 days. Faecal streptococci were reduced from 107 to less than 102 org./g within 30 days. The process consistently produced a good quality sanitised material under a range of control regimes.

Study on the effect of chitosan conditioning on sludge dewatering

2019 ◽  
Vol 79 (3) ◽  
pp. 501-509 ◽  
Author(s):  
Jin Zhang ◽  
Qing Hu ◽  
Jie Lu ◽  
Shuang Lin
Keyword(s):  
Moisture Content ◽  
Extracellular Polymeric Substances ◽  
Waste Water Treatment ◽  
Sewage Treatment ◽  
Organic Polymer ◽  
Sludge Dewatering ◽  
Sludge Treatment ◽  
Residual Sludge ◽  
Sludge Cake ◽  
Polymer Flocculant

Abstract The difficulty of residual sludge dehydration is the major problem in sewage treatment. The reduction of moisture content in sludge can reduce the sludge volume significantly and is conducive to the subsequent disposal of sludge. As an organic polymer flocculant, chitosan (CTS) is widely used in water and waste water treatment. In this study, CTS was used in sludge treatment to improve the sedimentation and dehydration properties of sludge. When treated with CTS, the moisture content of sludge cake decreased from 85.9% to 83.0%, the SV30 decreased to about 1/2, and the sludge volume reduced to 82.9%. Further analysis showed that the zeta potential (ζ-potential) of the sludge changed from negative value to positive value, and the D50 of the sludge was larger than that of the raw sludge. In addition, when the moisture content of the sludge cake was reduced to the lowest, the concentration of extracellular polymeric substances (EPS) and SCOD was the largest and the |ζ| decreased to the lowest. CTS improved the dehydration and sedimentation performance of sludge mainly by factors of electrical neutralization, adsorption bridging and dissolution of EPS.

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