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Sewage Disposal Systems
Published in Herman Koren, Best Practices for Environmental Health, 2017
A sequencing batch reactor is a variation of the activated sludge process where all biological treatment occurs in a single tank. The sludge is removed to a digester and the effluent is disinfected. This type of system is used where there is little suitable land available for sewage waste processing and disposal and minimal operator attendance. It is good for industries with high BOD levels in the wastewater and requiring nitrification, denitrification, and removal of phosphorus. These units optimize the treatment efficiency and do so in a single tank which lowers the requirement for energy and space. They have few operational or maintenance problems and can be operated remotely. Sludge must be disposed of frequently and it is difficult to adjust the cycling times for a small community. Small units can have problems with operation, maintenance, and hydraulic loading.
Long Term Effects of Salt on Activity, Population Structure and Floc Characteristics in Enriched Bacterial Cultures of Nitrifiers
Published in Moustafa Samir Moussa, Nitrification in Saline Industrial Wastewater, 2014
The study was carried out in three laboratory scale reactors with a working volume of 2.5 L each. The three reactors were operated automatically as Sequenced Batch Reactors (SBRs) at 30°C (Figure 4.1). The pH was maintained at 7.5±0.05 using 0.25 M NaOH and 0.25 M HCl (BIO controller ADI 1030 coupled with BioXpert l.lx data acquisition and control program; Applikon b.v. Schiedam, The Netherlands). The SBR systems were operated identically in cycles of 6 hours including 10 minutes fill period, 4 hours reaction period, 80 minutes for settling, and 30 minutes for effluent discharge. The SBR was fed with a synthetic medium containing mainly ammonia and nutrients to enhance the microbial growth. 1.5 L of medium was fed during the filling period. A similar volume was pumped out of the reactor at the end of the settling period, resulting in a volumetric exchanging ratio of 0.6 and hydraulic residence time of 10 h. The Sludge Retention Time (SRT) in the three reactors was adjusted at 30 days by the amount of wasted sludge removed from the mixed reactor during each cycle and the biomass in the effluent. Aeration was provided during the reaction period with airflow of 120 L/h. The three reactors were continuously monitored (on-line measuring of DO, pH, addition of NaOH) and sampled (MLSS, MLVSS, NH4+, N02−, NO3−) during several cycles. The main characteristics of the three reactors were as follows:
Secondary treatment
Published in Rumana Riffat, Taqsim Husnain, Fundamentals of Wastewater Treatment and Engineering, 2022
The SBR is a fill-and-draw-type of system where aeration, biodegradation, and settling all take place in a single reactor. The reactor sequences through a number of steps in one cycle. The reactor can go through 2–4 cycles per day. A typical cycle consists of the following steps: (i) Fill – where the substrate is added; (ii) react – mixing and aeration is provided; (iii) settle – for clarification of effluent; (iv) decant – for withdrawal of effluent. An idle step may also be included to provide flexibility at high flows. Aeration is accomplished by jet aerators or coarse bubble diffusers with submerged mixers.
Effects of perlite and caustic soda on microorganism activities of leachate in a sequence batch reactor
Published in Environmental Technology, 2018
Etesam Ganjian, Majid Peyravi, Ali Asqar Ghoreyshi, Mohsen Jahanshahi, Soodabeh Khalili, Ali Shokuhi Rad
Many technologies are available for the treatment of young leachate to decrease the negative effects. This work focused on biological treatment by a sequence batch reactor (SBR) operation because of its easy operation and cost-effectiveness. Generally, an SBR has been extensively employed for the treatment of domestic, municipal, industrial, dairy, synthetic, toxic and slaughterhouse wastewaters, swine manure, and LFLs [6–18]. The SBR process is a type of activated sludge (AS) process that used suspended natural biological and bacteria growth to remove contaminants. In AS, microorganisms oxidize organic matter because the main nutrient for microorganism growth is the organic matter in the mixed liquor. With the addition of LFL, the growth rate increases exponentially and then levels off. Figure S1 (see SI†) indicates the metabolism of bacteria in the presence of nutrient. This shows how the bacterial metabolism could have a direct relationship with degradation of contaminates and promote the treatment process [19]. There are two major processes in a bacterium: Catabolism or respiration: carbon ingestion + O2 → energy (protein + H2O) + CO2Anabolism or growth: carbon ingestion + energy → new biomass
Study on the effect of total dissolved solids (TDS) on the performance of an SBR for COD and nutrients removal
Published in Journal of Environmental Science and Health, Part A, 2018
Sarah (Xiao) Wu, Jason Maskaly
Sequencing batch reactors (SBR) have been researched extensively in the past,[1] and the working mechanism behind the SBR treatment is built on taking advantage of the metabolic needs of different bacterial groups including autotrophs, heterotrophs, and phosphorus accumulating organisms (PAOs) to promote synergistic activities and simultaneously achieve breakdown of organics and removal of nitrogen and phosphorus from the treated liquid. Due to its flexibility in changing the pattern of running phases in a cycle, such as anaerobic/anoxic/ aerobic, SBR has been widely adopted to treat many agricultural and industrial wastewaters, including swine and dairy manure,[2,3] food processing wastewater,[4,5] paper industry effluent,[6] landfill leachate,[7] and hypersaline wastewater.[8] However, most of the previous research on SBR operation are mainly focused on determining the optimum operating parameter(s), such as pH, oxidation-reduction potential (ORP), hydraulic retention time (HRT), etc., for the SBR under study to remove the concerned nutrients from a particular wastewater type,[9,10] with less from the perspective of the wastewater characteristics. It is well recognized that the treatability of any wastewater by an SBR is closely dependent upon the wastewater properties, and one of those parameters that may impact the performance of an SBR, but has not received sufficient research, is the total dissolved solids content (TDS) in the wastewater undergoing treatment.
Supervisory fuzzy control system for biological processes in sequencing wastewater batch reactor
Published in Urban Water Journal, 2020
The main advantage of the SBR is great operational flexibility that allows the plant to adjust its operating parameters to specific working conditions. To fully utilize this potential, a heuristic fuzzy controller was proposed. The process of designing this control system is described in detail. The comparative analysis of the simulation results is also presented. To validate the proposed control system within a wide operating range, three cases of pollutant concentrations were considered. The savings amounted to more than 9%. At the same time, the outflow pollutant restrictions were met. High quality of DO control was achieved.