Search results for "Sludge treatment"
showing 10 items of 22 documents
A software for the integrated design of wastewater treatment plants
1998
Abstract A software package has been developed for automated design of wastewater treatment plants. A user-friendly environment has been implemented to facilitate design tasks, allowing rapid evaluation of different alternatives as well as performing sensitivity analyses. Flexible treatment plant configurations can be established with preliminary, primary, biological and tertiary wastewater treatments, and sludge treatment units. A generalized steady-state model developed for biological processes is also included. The design process includes treatment units sizing, plant layout, hydraulic profile calculation and equipment assignment. The system capabilities for designing new plants and upgr…
Membrane bioreactors sludge: From production to disposal
2020
Abstract This chapter reviews the MBR activated sludge from production to disposal. Starting from sludge characterization, the chapter first presents the features of MBR sludge (morphology and EPS chemical composition), also in terms of differences with the activated sludge from conventional activated sludge plants. Sludge dewaterability is then discussed, focusing on the differences between aerobically and anaerobically digested sludge. An analysis of the costs related to MBR sludge treatment and disposal also is presented in order to provide a framework for a sustainable MBR sludge management.
Eubacteria and archaea communities in seven mesophile anaerobic digester plants in Germany
2015
Background Only a fraction of the microbial species used for anaerobic digestion in biogas production plants are methanogenic archaea. We have analyzed the taxonomic profiles of eubacteria and archaea, a set of chemical key parameters, and biogas production in samples from nine production plants in seven facilities in Thuringia, Germany, including co-digesters, leach-bed, and sewage sludge treatment plants. Reactors were sampled twice, at a 1-week interval, and three biological replicates were taken in each case. Results A complex taxonomic composition was found for both eubacteria and archaea, both of which strongly correlated with digester type. Plant-degrading Firmicutes as well as Bacte…
Fate of PCDD/PCDF during mechanical–biological sludge treatment
2004
Abstract In this preliminary study the seventeen 2,3,7,8-substituted congeners of PCDD/PCDF were analyzed at the inlet and outlet water and for three sewage sludge samples taken from different treatment stages to check behaviours of PCDD/PCDF at a municipal wastewater treatment plant (MWTP) in Poland. At the inlet (untreated sewage) water dominated PCDD congeners, whereas in the outlet (treated water) dominated the PCDF congeners. The octaCDD, 1,2,3,4,6,7,8-heptaCDD/CDF and octaCDF congeners dominated in all of the sludge samples. The total toxicity load gradually increased in the series excess, digested and dewatered sludge and amounted to 12.2, 14.4 and 16.9 ng I-TEQ kg −1 .
Struvite precipitation assessment in anaerobic digestion processes
2008
Struvite precipitation causes important operational problems during the sludge treatment process, especially when EBPR sludge is treated. Predicting struvite formation is critical to be able to design process alternative that best minimises struvite precipitation. With this aim, phosphorus precipitation in an anaerobic digestion pilot plant was studied using experimental data and mass balance analysis. The results obtained showed significant phosphorus precipitation as struvite (58% of the fixed phosphorus) and a low precipitation of calcium phosphates (15%), forming mainly hydroxyapatite (HAP). The rest of the phosphorus fixed in the digester (27%) was attributed to adsorption processes on…
Evaluation of the fuel potential of sewage sludge mixtures with beech sawdust and lignite
2018
Sewage sludge (SS) from municipal wastewater treatment has drawn serious attention of scientists around the world in the attempt to find feasible disposal methods. Therefore, in this work, a solution for valorisation of SS as solid fuel is proposed based on an advanced compositional investigation of SS versus conventional solid fuels, namely, lignite (L) and beech sawdust (BS). A characterisation in terms of proximate analysis and ultimate analysis was performed for the studied materials, both to SS, L, and BS as single fuel and to bi-component mixture formulas of SS and L/BS, in variable proportions of 30:70, 50:50, and 70:30. SS:BS based blends had higher hydrogen (from 4.43 wt. % to 5.14…
Characteristics of rice straw and sewage sludge as composting materials in Valencia (Spain).
2004
This work supports the idea that composting can be useful for minimizing the rice straw and sewage sludge environmental impact. Several physical, chemical and microbiological properties of these raw materials were analyzed. The characteristics of the rice straw were complementary to those of the sewage sludge for the application of composting. The C/N ratios suitable for a rapid increased in microbial activity were the lowest (17-24). A temperature of 62 degrees C during 48 h removed pathogenic microorganisms from rice straw and sewage sludge mixture. The results obtained in the present work suggested that these materials could be use in the composting process.
Environmental assessment of the Sibiu County, Romania: proposal for sewage sludge and OFMSW management
2017
The aim of the work is to assess current solid waste management (SWM) and wastewater treatment (WWT) in the county of Sibiu, Romania. Sibiu is a region where industrialization and tourism are spreading constantly, while pollution monitoring and the introduction of circular economy (CE) principles are still lacking. The environmental issues are mostly due to the absence of reliable sanitation systems, in particular for what concerns sewage sludge treatment. Moreover, Organic fraction from selective collection of municipal solid waste is still missing, since it is disposed of directly to landfill, increasing environmental pollution and contributing considerably to global warming. As a result,…
Removal of bis(2-ethylhexyl) phthalate at a sewage treatment plant
2003
Bis(2-ethylhexyl) phthalate (DEHP) concentrations were measured at different stages in a full-scale sewage treatment plant (STP) and mass balances were calculated. The DEHP load to treatment process coming from the sewer system and the internal load comprising returned supernatants and filtrate from sludge treatment and excess secondary sludge were at the same level. The DEHP removal efficiency from the water phase at the STP was on average 94% of sewage DEHP, the main removal process being sorption to primary and secondary sludges. On average 29% of DEHP was calculated to be removed in the biological nitrifying-denitrifying activated sludge process, which was much less than expected from l…
Pharmaceuticals in processing of municipal sewage sludge studied by grab and passive sampling
2018
Abstract Concentrations of pharmaceuticals, consisting of four anti-inflammatory and one antiepileptic drug, were studied in the aqueous and solid phase of municipal sewage sludge, collected from a wastewater treatment plant (WWTP) in central Finland. The samples included untreated municipal sludge from the biological wastewater treatment, digested sludge and sludge before and after composting. First, samples were taken as grab samples to study the bioavailable part in aqueous phase but also the part in solid fraction. Later, the long-term concentrations were studied by passive sampling with styrene divinylbenzene-reverse phase sulfonated (SDB-RPS) disks. In the untreated solid sludge, the …