scholarly journals Content of Polycyclic Aromatic Hydrocarbons (PAHs) and Other Compounds in Autothermal Thermophilic Aerobic Digestion (ATAD) Leachates—The Issue of Returned Leachates

Proceedings ◽  
2020 ◽  
Vol 51 (1) ◽  
pp. 28
Author(s):  
Dariusz Boruszko ◽  
Ada Wojciula

Sewage sludge is a by-product of the municipal wastewater treatment process. The amount of sewage sludge generated in treatment plants in Poland and other European countries is constantly growing. Due to the growing environmental awareness, legal requirements are being established that require the appropriate treatment of sludge before it can be used for natural purposes. Therefore, operators are looking for the best solutions to ensure proper sewage sludge preparation. More and more ATAD (auto-thermophilic sewage sludge stabilization) installations are being built in Poland, which allow for simultaneous stabilization and hygienization of sludge. However, this process contributes to the formation of leachate, which is discharged into the biological reactors of municipal sewage treatment plants. The leachate after the ATAD process has a complex organic substance and is characterized by large loads of total nitrogen and total phosphorus. Biological wastewater treatment processes can be ineffective for such specific pollutants returned in ATAD leachate. Thus far, no research has been undertaken to analyze the problem presented.

2020 ◽  
Vol 15 (1) ◽  
pp. 160-169 ◽  
Author(s):  
Yeshi Cao ◽  
M. C. M. Van Loosdrecht ◽  
Glen. T. Daigger

Abstract Since about the 1990s China has achieved remarkable progress in urban sanitation. The country has built very extensive infrastructure for wastewater treatment, with 94.5% treatment coverage in urban areas and legally mandated nation-wide full nutrient removal implemented. However, municipal wastewater treatment plants (WWTPs) in China are still confronted with issues rooted in the unique sewage characteristics. This study compares energy recovery, cost of nutrient removal and sludge production between Chinese municipal WWTPs and those in countries with longer wastewater treatment traditions, and highlights the cause-effect relationships between Chinese sewage characteristics – high inorganic suspended solids (ISS) loads, and low COD and C/N ratio, and municipal WWTP process performance in China. Integrated design and operation guidelines for municipal WWTPs are imperative in relation to the unique sewage characteristics in China. Cost-effective measures and solutions are proposed in the paper, and the potential benefits of improving the sustainability of municipal WWTPs in China are estimated.


Water ◽  
2021 ◽  
Vol 13 (20) ◽  
pp. 2850
Author(s):  
Yinan Zhang ◽  
Shihuan Lu ◽  
Yuxin Fang ◽  
Kexin Yang ◽  
Jiafeng Ding ◽  
...  

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.


1992 ◽  
Vol 25 (12) ◽  
pp. 185-195 ◽  
Author(s):  
G. Garuti ◽  
M. Dohanyos ◽  
A. Tilche

Results of a four year experience on a combined anaerobic-anoxic-oxic municipal wastewater treatment process - named ANANOX® - are presented. This process demonstrated to be highly efficient, with 89.6% CODt, 89.2% TSS and 81.2% N removal, and a sludge production of only 0.2 kg TSS.kg COD removed−1, a value which is roughly 50% less if compared with traditional nitrification/denitrification processes. Energy needs are reduced with respect to aerobic plants, because the anaerobic COD degradation plays a major role, particularly during the warm season. Sulphates play a very significant role in the process because, after being reduced in the anaerobic step, where they give a contribution to the organic matter degradation, they are reoxidized in the anoxic step by nitrates, reducing the organic matter need for denitrification. Due to the high dependence of efficiency on temperature, the system proposed has advantageous uses for sewage treatment particularly in warm climates and in tourist and recreational areas where the population increases during the warm season.


2012 ◽  
Vol 518-523 ◽  
pp. 2324-2327
Author(s):  
Jun Feng Wu ◽  
Hua Shu Ouyang ◽  
Xian Li Wang

To alleviate the water pollution, the original wastewater treatment process was transformed based on the existing structures. Anaerobic-anoxic-aerobic process (A2/O process) was used as the main process, instead of the original two-stage aeration process (AB process). Pretreatment process and advanced treatment process were strengthened. After transformation, the effluent quality could meet the first class of A standard of the "municipal wastewater treatment plant emission standards" (GB18918-2002) and all the quality indexes of the treated water met the requirements of discharge standard of sewage treatment. The original structures were fully used in this transformation, saving investment, which provided a practical reference for the transformation of the wastewater treatment plants.


2018 ◽  
Vol 45 ◽  
pp. 00054 ◽  
Author(s):  
Bozena Mrowiec

The aim of this paper was to review the literature data regarding the physico-chemical characteristic of plastic pollutants discharged with municipal sewage, the practical possibility of removing microplastic particles from wastewater during different treatment steps in WWTPs and the problem of surface water contamination within them. Microplastics (the size range of 1 nm to < 5 mm), have been recognized as an emerging threat, as well as an ecotoxicological and ecological risk for water ecosystems. Municipal wastewater treatment plants (WWTPs) are mentioned as the main point sources of microplastics in an aquatic environment. Microplastic particles can be effectively removed in the primary treatment zones via solids skimming and sludge settling processes. Different tertiary treatment processes such as: gravity sand filtration, discfilter, air flotation and membrane filtration provide substantial additional removal of microplastics, and the efficiency of wastewater treatment process can be at a removal level of 99.9%. Nevertheless, given the large volumes of effluent constantly discharged to receivers, even tertiary level WWTPs may constitute a considerable source of microplastics in the surface water.


2019 ◽  
Vol 252 ◽  
pp. 05010
Author(s):  
Paweł Król ◽  
Alberto Gallina ◽  
Michał Lubieniecki ◽  
Tadeusz Uhl ◽  
Tadeusz Żaba

Waste management is a crucial process to keep the environment in wholesome conditions. The environmental impact of solid waste and wastewater is reduced through construction of appropriate disposal installations. The objective of wastewater treatment in biological reactors is to control the process of biomaterial growth by aerating the sewage content. The process is complex, as depending on a plenty of parameters. In the last decades an effective numerical model, called the Activated Sludge Model (ASM), has been proposed for describing the biological process. The ASM is implemented in the Benchmark Simulation Model (BSM) that simulates the whole wastewater treatment process. The most important parameters in ASM are the kinetic and stoichiometric coefficients. The former describes rate-concentration dependence. The latter characterises the relationship between the components of chemical reactions taking place in the cleaning process. Above parameters are determined by on-site calibration and their importance is relevant during the development of numeric models. This paper aims to examine the influence of kinetic and stoichiometric parameters on the wastewater treatment process of a plant in Płaszów, Kraków. The analysis is carried out by a sample-based numerical procedure. It highlights the ASM parameters playing a major role in the treatment process. Results obtained from the analysis are important for future validation and optimisation processes.


2018 ◽  
Vol 77 (11) ◽  
pp. 2613-2623 ◽  
Author(s):  
Kerstin Schopf ◽  
Johannes Judex ◽  
Bernhard Schmid ◽  
Thomas Kienberger

Abstract A municipal wastewater treatment plant accounts for a large portion of the total energy consumption of a municipality. Besides their high energy demand, the plants also display a significant bioenergy potential. This is due to the utilisation of the energy content of digester gas and sewage sludge if there exist suitable units. To maximise the energy recovery efficiency of wastewater treatment systems (WWTS), it is important to analyse the amount of digester gas and sludge produced in different types of plants. Therefore, the present paper deals with designing a tool to answer the following research questions: Which bioenergy potentials occur in different plant types? Which mass and energy flows are related to the specific potentials? Which utilisation processes for the potentials can lead to a high energy recovery efficiency of WWTS? Preliminary analyses with the designed tool were focused on estimating the level of electric and thermal energy self-sufficiency of different plant configuration scenarios including or excluding digester gas and/or sludge utilisation units. First results based on the level of self-sufficiency and associated energy and disposal costs show that a digester gas and sewage sludge utilisation should be considered when designing future WWTS.


Water ◽  
2019 ◽  
Vol 12 (1) ◽  
pp. 23 ◽  
Author(s):  
Magdalena Łój-Pilch ◽  
Anita Zakrzewska

Nowadays, risk management applies to every technical facility, branch of the economy, and industry. Due to the characteristics of the analyzed wastewater treatment plant and the specificity of the used processes, one must approach different areas individually. Municipal sewage treatment plants are technical facilities; they function as enterprises and are elements of larger systems—water distribution and sewage disposal. Due to their strategic importance for the environment and human beings, it is essential that they are covered by risk management systems. The basic stage of risk management is its assessment. On its basis, strategic decisions are made and new solutions are introduced. Constant monitoring of the operation of a treatment plant allows for assessment of whether actions taken are correct and whether they cause deterioration of the quality of sewage. In our work, we present a method of risk assessment based on historical data for an existing facility and obtained results.


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