Digestion and Disposal of Primary and Secondary Sludge

2019 ◽  
pp. 255-292
Keyword(s):  
Wastewater Treatment ◽  
Sewage Sludge ◽  
Chemical Precipitation ◽  
Complex Problem ◽  
Waste Biomass ◽  
Primary Sludge ◽  
Treatment Processes ◽  
Secondary Sludge ◽  
Biological Treatments ◽  
Treatment And Disposal

Sewage sludge is the solid, semisolid, or slurry residual material that is produced as a byproduct of wastewater treatment processes. This residue is commonly classified as primary and secondary sludge. Primary sludge is generated from chemical precipitation, sedimentation, and other primary processes, whereas secondary sludge is the activated waste biomass resulting from biological treatments. Quite often the sludges are combined together for further treatment and disposal. Sludge from biological treatment operations is sometimes referred to as wastewater biosolids. Of the constituents removed by the treatment, solids and biosolids are by far the largest in volume, and their processing, reuse, and disposal present perhaps the most challenging environmental problem and complex problem in wastewater treatment processes. Therefore, the chapter is devoted to the discussion of the sources, characteristics, quantities, disposal, digestion, and stabilization of sludge so as to present background data and information on these topics that will serve as a basis for the designing of sludge processing, treatment, and disposal facilities.

Microflore hétérotrophe impliquée dans le procédé simultané de biolixiviation des métaux et de digestion des boues d'épuration

2001 ◽  
Vol 28 (1) ◽  
pp. 158-174 ◽  
Author(s):  
M Gamache ◽  
J F Blais ◽  
R D Tyagi ◽  
N Meunier
Keyword(s):  
Sewage Sludge ◽  
Heterotrophic Bacteria ◽  
Bacterial Species ◽  
Microbial Populations ◽  
Primary Sludge ◽  
Sludge Digestion ◽  
Isolation And Characterization ◽  
Secondary Sludge ◽  
Blastoschizomyces Capitatus

Until now, some microbiological studies have made it possible to highlight the role and identification of certain chimiolithotroph microorganisms directly involved in the simultaneous sewage sludge digestion and metal leaching (SSDML process). Moreover, some other studies have established the performance of the SSDML process for the destruction of pathogens. However, until now no study has been carried out to define the equilibrium of the heterotrophic microbial populations during the sludge acidification occurring during the operation of the SSDML process. Hence, the SSDML process was studied in batch and continuous mode employing different types of sludges (Communauté Urbaine de Québec (CUQ)-East primary sludge, Beauceville secondary sludge, and mixture of primary and secondary Valcartier sludge). The equilibrium of heterotrophic microbial populations was investigated along with sludge acidification and solids degradation. The results obtained during the SSDML process on different sludges showed a decrease followed by the destruction of a majority of heterotrophic bacterial species found in fresh sludges. The isolation and characterization of different microbial species showed that only two types of microorganisms persisted: the yeast Blastoschizomyces capitatus and an unidentified fungus.Key words: sewage sludge, simultanous bioleaching and digestion, heterotrophic bacteria, Blastoschizomyces capitatus, fungi.

Control of Cryptosporidium with wastewater treatment to prevent its proliferation in the water cycle

2003 ◽  
Vol 47 (9) ◽  
pp. 45-49 ◽  
Author(s):  
M. Suwa ◽  
Y. Suzuki
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Municipal Wastewater ◽  
Water Cycle ◽  
River System ◽  
Chemical Precipitation ◽  
Aluminium Chloride ◽  
Activated Sludge Process ◽  
Sand Filter ◽  
Treatment Processes

The outbreak of Cryptosporidiosis in 1996 in Japan is thought to have been enlarged by the proliferation of Cryptosporidium in the water cycle from wastewater to drinking water through the river system. From this experience, the wastewater system must have functions to remove Cryptosporidium oocysts effectively. Efficiencies of wastewater treatment processes to remove oocysts were investigated using pilot plants receiving municipal wastewater. An activated sludge process and a following sand filter showed removal efficiencies of 2 log and 0.5 log, respectively. Poly-aluminium chloride dosage improved the efficiencies by 3 log for the activated sludge process and by 2 log for the sand filter. Chemical precipitation of raw wastewater with poly-aluminium chloride could achieve 1 to 3 log removal according on the coagulant concentration.

Heavy Metal Potential of Domestic Biological Wastewater Treatment Plant Sludge

2021 ◽  
Vol 4 (1) ◽  
pp. 90-113
Author(s):  
T.D.C. Pushpakumara ◽  
◽  
W.G.T. Sandakelum ◽  
Keyword(s):  
Heavy Metal ◽  
Wastewater Treatment ◽  
Wastewater Treatment Plant ◽  
Metal Content ◽  
Treatment Plant ◽  
Nutrient Content ◽  
Heavy Metal Content ◽  
Treatment Processes ◽  
Secondary Sludge

The use of sludge as fertilizers helps to the recycling of nutrients to the environment due to its beginning from wastewater and therefore relatively high content of nutrients and organic matter. However, wastewater does also contain hazardous compounds like heavy metals and micro pollutants which eventually are separated to the sludge during the treatment processes at the wastewater treatment plant. In order to improve the sludge quality, source tracking is a relatively cheap and effective way to find and eliminate hazardous compounds and prevent them from ending up in the sludge. The aim with this thesis was to investigate the fertilizer potential in sludge from wastewater treatment plant. The sludge is analyzed in terms of nutrient and heavy metal contents as well as physiochemical parameters. In order to determine the potential as fertilizer, the quality of the sludge is compared with other fertilizer alternatives, other sludge types and regulations for sludge use in agriculture. The work with sludge quality improvements in Gaborone is also investigated. Sludge from different stages along the treatment processes were collected in order to see differences in quality related to the treatment. The results shows that the samples of primary an aerobically treated sludge tend to have higher heavy metal content than the secondary sludge. The quality of the dry sludge samples indicates lower nutrient content than both the primary and secondary sludge, but similar heavy metal content. The analysis of dry sludge from indicates a low nutrient value and high heavy metal content in comparison to other selected fertilizer options and sludge from other. The processes for removal of nutrients from the wastewater are an important factor for the nutrient content in the sludge. Keywords wastewater; fertilizers; nutrients; sludge treatment

Estimation of pharmaceutical residues in primary and secondary sewage sludge based on quantities of use and fugacity modelling

2002 ◽  
Vol 46 (3) ◽  
pp. 105-113 ◽  
Author(s):  
S.J. Khan ◽  
J.E. Ongerth
Keyword(s):  
Sewage Sludge ◽  
General Procedure ◽  
Analytical Data ◽  
Primary Sludge ◽  
Pharmaceutical Residues ◽  
Secondary Sludge

A general procedure was developed for estimating the concentrations of pharmaceutical residues in fresh primary and secondary sewage sludge. Prescribed quantities coupled with information on the various excretion ratios of 20 pharmaceuticals and 2 of their metabolites enabled prediction of the overall rates of excretion into Australian sewage. Fugacity modelling was applied to predict concentrations of these residues in fresh primary and secondary sludge. Predicted concentrations ranged from 10−3 - 884 μg/L in primary sludge and 10-4 - 36 μg/L in secondary sludge. Overall rates of removal to sludges ranged from 1-39%. The accuracy of the model was verified by comparison to analytical data.

scholarly journals Influence of Wastewater Treatment and The Method of Sludge Disposal on the Gasification Process

2014 ◽  
Vol 21 (2) ◽  
pp. 255-268 ◽  
Author(s):  
Sebastian Werle ◽  
Mariusz Dudziak
Keyword(s):  
Wastewater Treatment ◽  
Sewage Sludge ◽  
Wastewater Treatment Plant ◽  
Municipal Wastewater ◽  
Fixed Bed ◽  
Treatment Plant ◽  
Experimental Investigations ◽  
Heating Value ◽  
Treatment Processes ◽  
Sludge Disposal

Abstract Municipal wastewater treatment results in the production of large quantities of sewage sludge, which requires proper environmentally accepted management before final disposal. Sewage sludge is a by-product of current wastewater treatment technologies. Sewage sludge disposal depends on the sludge treatment methods used in the wastewater treatment plant (anaerobic or aerobic digestion, drying, etc.). Taking into consideration presented given this information, a study concerning the effects of wastewater treatment processes and sewage sludge drying method on the sewage sludge gasification gas parameters was performed. Gasification is a prospective alternative method of sludge thermal treatment. For the purpose of experimental investigations, a laboratory fixed bed gasifier installation was designed and built. Two types of sewage sludge feedstock, SS1 and SS2, were analyzed. Sewage sludge SS1 came from a wastewater treatment plant operating in the mechanical and biological system while sewage sludge SS2 was collected in a mechanical, biological and chemical wastewater treatment plant with simultaneous phosphorus precipitation. The sludge produced at the plants was subject to fermentation and then, after being dehydrated, dried in a cylindrical drier on shelves heated up to 260ºC (sewage sludge SS1) and using hot air at a temperature of 150ºC in a belt drier (sewage SS2). The analysis shows that the sewage sludge properties strongly depend on the wastewater sources and the wastewater treatment processes. The gasification results, presented as a function of the amount of gasification agent, show that the greater oxygen content of SS1 caused a reduction in the reaction temperature. Paradoxically, this effect caused an increase in the quantity of combustible components in the gas. As expected, increasing the air flow rate caused a decrease in the heating value of the gas produced. A higher amount of oxidizer increases the amounts of noncombustible species and the volumetric fraction of nitrogen, thus reducing the heating value of the obtained gas. The higher hydrogen content in SS1 affects the gasification gas composition. As a result, combustible components are the majority of the syngas.

Comparison among the most frequently used systems for wastewater treatment in developing countries

1996 ◽  
Vol 33 (3) ◽  
pp. 59-72 ◽  
Author(s):  
Marcos von Sperling
Keyword(s):  
Developing Countries ◽  
Wastewater Treatment ◽  
Main Process ◽  
Qualitative Comparison ◽  
Summary Table ◽  
Trickling Filters ◽  
Advantages And Disadvantages ◽  
Usable Information ◽  
Treatment Processes ◽  
Treatment And Disposal

The paper presents a series of tables, figures and charts which can be used for the preliminary selection of wastewater treatment systems, specially in developing countries. The systems analysed are: stabilization ponds, activated sludge, trickling filters, anaerobic systems and land disposal. Within each system, the main process variants are covered. A main summary table for quantitative analysis is presented, including easily usable information based on per capita values (US$/cap, W/cap, m2 area/cap, m3 sludge/cap). Other tables for qualitative comparison among systems are also included, one based on a one-to-five-star scoring and the other on a balance between advantages and disadvantages of the main treatment processes. The sludge treatment and disposal is also covered, including a comparative analysis based on a scoring system.

scholarly journals Fate of Emerging Contaminants in High-Rate Activated Sludge Systems

2021 ◽  
Vol 18 (2) ◽  
pp. 400
Author(s):  
Elena Koumaki ◽  
Constantinos Noutsopoulos ◽  
Daniel Mamais ◽  
Gerasimos Fragkiskatos ◽  
Andreas Andreadakis
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Emerging Contaminants ◽  
Endocrine Disrupting Chemicals ◽  
High Rate ◽  
Sustainable Technologies ◽  
Treatment Processes ◽  
Secondary Sludge ◽  
Positive Treatment ◽  
Dominant Process

High-rate activated sludge (HRAS) systems are designed to shift the energy-intensive processes to energy-saving and sustainable technologies for wastewater treatment. The high food-to-microorganism (F/M) ratios and low solid retention times (SRTs) and hydraulic retention times (HRTs) applied in HRAS systems result in the maximization of organic matter diversion to the sludge which can produce large amounts of biogas during anaerobic digestion, thus moving toward energy-neutral (or positive) treatment processes. However, in addition to the energy optimization, the removal of emerging contaminants (ECs) is the new challenge in wastewater treatment. In the context of this study, the removal efficiencies and the fates of selected ECs (three endocrine disruptors (endocrine disrupting chemicals (EDCs))—nonylphenol, bisphenol A and triclosan, and four pharmaceuticals (PhACs)—ibuprofen, naproxen, diclofenac and ketoprofen) in HRAS systems have been studied. According to the results, EDCs occurred in raw wastewater and secondary sludge at higher concentrations compared to PhACs. In HRAS operating schemes, all compounds were poorly (<40%) to moderately (<60%) removed. Regarding removal mechanisms, biotransformation was found to be the dominant process for PhACs, while for EDCs sorption onto sludge is the most significant removal mechanism affecting their fates and their presence in excess sludge.

scholarly journals Species and Bio-Availability of Inorganic and Organic Phosphorus in Primary, Secondary and Digested Sludge

2018 ◽  
Author(s):  
Shaoxiang Zhang ◽  
Wenli Huang ◽  
Dongfang Liu
Keyword(s):  
Sewage Sludge ◽  
Organic Phosphorus ◽  
Treatment Plant ◽  
Optimal Choice ◽  
Land Application ◽  
Digested Sludge ◽  
Primary Sludge ◽  
Secondary Sludge ◽  
Study Results ◽  
P Fraction

The species and bio-availability of phosphorus (P) in primary, secondary and digested sludge were fractionated and further analyzed in this study. Results showed that inorganic P (IP) was the primary P fraction in the secondary sludge and digested sludge, in which non-apatite IP (NAIP) amounted to 91.6% and 69.3% of IP, respectively. Organic P (OP), accounting for about 71.7% of total P (TP), was the dominant P composition in primary sludge. The content of bio-available P was about 9.7, 43.4, 29.8 mg-P/g-TS in primary sludge, secondary sludge and digested sludge, respectively, suggesting secondary sludge is the optimal choice when land application of sewage sludge is taken into consideration, followed by digested sludge and primary sludge. Polyphosphate and orthophosphate, comprising approximately 54.3% and 89.2% of TP, was the dominant P species in the secondary sludge and digested sludge, respectively. Monoester-P (54.6% of TP in extract) and diester- P (24.1%) were identified as OP species in primary sludge by Phosphorus-31 nuclear magnetic resonance (31PNMR). The present results would be helpful for P recovery and recycle from sewage sludge in wastewater treatment plant.

Regional Sludge Treatment and Disposal Optimizing Reliability and Cost

1987 ◽  
Vol 19 (5-6) ◽  
pp. 847-857 ◽  
Author(s):  
Hermann H. Hahn
Keyword(s):  
Wastewater Treatment ◽  
Sewage Sludge ◽  
Optimization Problems ◽  
Selection Process ◽  
Practical Case ◽  
Sludge Treatment ◽  
Process Reliability ◽  
Treatment Facilities ◽  
Treatment And Disposal ◽  
Regional Solutions

Sewage sludge is the consequence of successful wastewater treatment. With the increasing number of wastewater treatment facilities and increasing intensity of treatment the amount of sludge produced will grow. The task of sludge treatment and disposal will therefore assume a significant place in environmental quality control. Sewage sludge is considered both a valuable resource possibly for agriculture, and a waste material which must be disposed of safely. Thus, regional solutions must be aimed for if available sites for agricultural application or a limited number of disposal sites are to be used wisely. Technically and economically feasible alternatives of treatment (and disposal) are numerous. The selection process to be discussed in this paper is a minimization of overall cost and/or an optimization of process reliability and cost. There exist proven mathematical tools for the solution of such optimization problems; in this instance dynamic programming routines have been utilized. The applicability of these methods, as well as their limits, are shown in a practical case study.

scholarly journals Coupling Hydrothermal Carbonization with Anaerobic Digestion for Sewage Sludge Treatment: Influence of HTC Liquor and Hydrochar on Biomethane Production

Energies ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 6262 ◽  
Author(s):  
Roberta Ferrentino ◽  
Fabio Merzari ◽  
Luca Fiori ◽  
Gianni Andreottola
Keyword(s):  
Wastewater Treatment ◽  
Anaerobic Digestion ◽  
Sewage Sludge ◽  
Wastewater Treatment Plants ◽  
Hydrothermal Carbonization ◽  
Digested Sludge ◽  
Sludge Treatment ◽  
Secondary Sludge ◽  
Sewage Sludge Treatment ◽  
Biomethane Production

The present study addresses the coupling of hydrothermal carbonization (HTC) with anaerobic digestion (AD) in wastewater treatment plants. The improvement in biomethane production due to the recycling back to the anaerobic digester of HTC liquor and hydrochar generated from digested sludge is investigated and proved. Mixtures of different compositions of HTC liquor and hydrochar, as well as individual substrates, were tested. The biomethane yield reached 102 ± 3 mL CH4 g−1 COD when the HTC liquor was cycled back to the AD and treated together with primary and secondary sludge. Thus, the biomethane production was almost doubled compared to that of the AD of primary and secondary sludge (55 ± 20 mL CH4 g−1 COD). The benefit is even more significant when both the HTC liquor and the hydrochar were fed to the AD of primary and secondary sludge. The biomethane yield increased up to 187 ± 18 mL CH4 g−1 COD when 45% of hydrochar, with respect to the total feedstock, was added. These results highlight the improvement that the HTC process can bring to AD, enhancing biomethane production and promoting a sustainable solution for the treatment of the HTC liquor and possibly the hydrochar itself.

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