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Wastewater Treatment Operations
Published in Frank R. Spellman, Handbook of Water and Wastewater Treatment Plant Operations, 2020
In operation, air may be supplied to the extended aeration package plant by mechanical or diffused aeration to provide the oxygen required to sustain the aerobic biological process. Mixing must be provided by aeration or mechanical means to maintain the microbial organisms in contact with the dissolved organics. In addition, the pH must be controlled to optimize the biological process and essential nutrients must be present to facilitate biological growth and the continuation of biological degradation. Wastewater enters the treatment system and is typically screened immediately to remove large suspended, settleable, or floating solids that could interfere with or damage equipment downstream in the process. Wastewater may then pass through a grinder to reduce large particles that are not captured in the screening process. If the plant requires the flow to be regulated, the effluent will then flow into equalization basins which regulate peak wastewater flow rates. Wastewater then enters the aeration chamber, where it is mixed and oxygen is provided to the microorganisms. The mixed liquor then flows to a clarifier or settling chamber where most microorganisms settle to the bottom of the clarifier and a portion is pumped back to the incoming wastewater at the beginning of the plant. This returned material is the RAS. The material that is not returned, the WAS, is removed for treatment and disposal. The clarified wastewater then flows over a weir and into a collection channel before being diverted to the disinfection system (USEPA, 2000)
Secondary Treatment
Published in David H.F. Liu, Béla G. Lipták, Wastewater Treatment, 2020
The extended-aeration process (see Figure 5.2.4) is similar to the conventional activated-sludge process except it operates in the endogenous respiration phase to reduce excess process sludge. As a result, the aeration basin is generally much larger. Only preliminary wastewater treatment to remove coarse materials is needed to protect treatment equipment. The extended-aeration process is designed for the treatment of wastewater generated from small installations and communities. Section 6.3 presents a detailed discussion on the extended-aeration process.
Aquatic Plant/Microbial Filters for Treating Septic Tank Effluent
Published in Donald A. Hammer, Constructed Wetlands for Wastewater Treatment, 2020
Biologically, the aquatic plant systems are far more diverse than present-day mechanical treatment systems. Oxidation ditches and other types of extended aeration treatment systems use energy-intensive mechanical aerators to supply large amounts of oxygen for growing aerobic microorganisms that treat the wastewater.
Effectiveness of combined tools: adsorption, bioaugmentation and phytoremediation for pesticides removal from wastewater
Published in International Journal of Phytoremediation, 2023
Rim Werheni Ammeri, Saifeddine Eturki, Giuseppe Di Rauso Simeone, Kawther Ben Moussa, Wafa Hassen, Mohamed Moussa, Abdennaceur Hassen
Some physical and chemical characteristics were carried out on STWW sample such as organic carbon, chloride, pH, conductivity, chemical oxygen demand, etc. The municipal wastewater used in this study, known as secondary treated wastewater (STWW), is treated at the El Hamma Wastewater Treatment Plant, which is part of the Gabes Provincial Administration and the El Hamma delegation (ONAS 2019). It is an activated sludge extended aeration plant with a mechanical screen, grit removal tanks, primary sedimentation, extended aeration, and final sedimentation tanks (Figure 2). The results were reported in Table 1 and showed that the pH of STWW is slightly alkaline, with a value of about 8.7 ± 0.1; the electrical conductivity (EC) was 2.8 ± 0.1 mS cm−1. Also, the STWW sample presented nitrogen content, COD, BOD5 and chloride content of 48.0 ± 1.0, 632.0 ± 5.1, 3.8 ± 1.0 and 14.6 ± 1.3 mg L−1, respectively.
A study about the performance evaluation of medical waste sterilization plant in Van, Turkey
Published in Journal of the Chinese Institute of Engineers, 2022
Laber, Haberl, and Shrestha (1999) reported 95% COD removal from hospital wastewater using a two-stage wetland. Aerobic systems are generally used for the biological treatment of MWSP wastewater, as anaerobic systems operate more efficiently with high pollution loads. One aerobic system used in small treatment plants is the extended aeration activated sludge system. MWSP wastewater generally consists of medium quality domestic wastewater, with a pH generally between 7 and 8 and is not therefore considered problematic for biological treatment. Many studies have been conducted about the application of electrochemical methods to MWSP wastewater. In the electrocoagulation process, the treatment of MWSP wastewater has been achieved with approximately 52% removal success under optimal conditions (Jain et al. 2001). Coagulation-flocculation processes are widely used in the treatment of domestic and industrial wastewater (Jain et al. 2001; Chuang et al. 2006; Suarez, Lema, and Omil 2009).
The design for wastewater treatment plant (WWTP) with GPS X modelling
Published in Cogent Engineering, 2020
This research is to explain the physical, chemical and biological properties of wastewater. Secondly, it is to design some parts of wastewater treatment plant in Al-Hay station. Therefore, the study of wastewater properties are important regarding to the biological and chemical wastewater treatment processes, which include (aerobic treatment such as (oxidation ponds and activated sludge) and anaerobic treatment. Also, the chemical wastewater treatment processes include chemical precipitation (coagulation and flocculation), ion exchange, neutralization and adsorption. Thus, studying the properties of wastewater has to be investigated because all important in terms of plant layout, plant design, plant sizing and plant location. In this study, it describes the process of preliminary design; secondary design is done based on extended aeration activated sludge system. This system is commonly used is Iraq because it is known technology with less expensive sludge treatment requirement and it can satisfy the standards criteria for effluent disposal to surface water. Finally, chlorination unit is a common method for pathogen reduction. Moreover, modelling and simulation of the process of design Al-Hay station is performed by GPS X program with some parameters.