Impact of carbon to nitrogen ratio and aeration regime on mainstream deammonification

2016 ◽  
Vol 74 (2) ◽  
pp. 375-384 ◽  
Author(s):  
M. Han ◽  
H. De Clippeleir ◽  
A. Al-Omari ◽  
B. Wett ◽  
S. E. Vlaeminck ◽  
...  
Keyword(s):  
Organic Carbon ◽  
Sewage Treatment ◽  
Oxygen Demand ◽  
Cost Savings ◽  
High Strength ◽  
Primary Treatment ◽  
High Rate ◽  
Potential Cost ◽  
Nitrite Oxidizing Bacteria ◽  
Chemically Enhanced Primary Treatment

While deammonification of high-strength wastewater in the sludge line of sewage treatment plants has become well established, the potential cost savings spur the development of this technology for mainstream applications. This study aimed at identifying the effect of aeration and organic carbon on the deammonification process. Two 10 L sequencing bath reactors with different aeration frequencies were operated at 25°C. Real wastewater effluents from chemically enhanced primary treatment and high-rate activated sludge process were fed into the reactors with biodegradable chemical oxygen demand/nitrogen (bCOD/N) of 2.0 and 0.6, respectively. It was found that shorter aerobic solids retention time (SRT) and higher aeration frequency gave more advantages for aerobic ammonium-oxidizing bacteria (AerAOB) than nitrite oxidizing bacteria (NOB) in the system. From the kinetics study, it is shown that the affinity for oxygen is higher for NOB than for AerAOB, and higher dissolved oxygen set-point could decrease the affinity of both AerAOB and NOB communities. After 514 days of operation, it was concluded that lower organic carbon levels enhanced the activity of anoxic ammonium-oxidizing bacteria (AnAOB) over denitrifiers. As a result, the contribution of AnAOB to nitrogen removal increased from 40 to 70%. Overall, a reasonably good total removal efficiency of 66% was reached under a low bCOD/N ratio of 2.0 after adaptation.

scholarly journals Rotating belt sieves for primary treatment, chemically enhanced primary treatment and secondary solids separation

2017 ◽  
Vol 75 (11) ◽  
pp. 2598-2606 ◽  
Author(s):  
B. Rusten ◽  
S. S. Rathnaweera ◽  
E. Rismyhr ◽  
A. K. Sahu ◽  
J. Ntiako
Keyword(s):  
Removal Efficiency ◽  
Oxygen Demand ◽  
Pilot Scale ◽  
Primary Treatment ◽  
Biofilm Reactors ◽  
Fine Mesh ◽  
Coagulation And Flocculation ◽  
Successful Removal ◽  
Solids Separation ◽  
Chemically Enhanced Primary Treatment

Fine mesh rotating belt sieves (RBS) offer a very compact solution for removal of particles from wastewater. This paper shows examples from pilot-scale testing of primary treatment, chemically enhanced primary treatment (CEPT) and secondary solids separation of biofilm solids from moving bed biofilm reactors (MBBRs). Primary treatment using a 350 microns belt showed more than 40% removal of total suspended solids (TSS) and 30% removal of chemical oxygen demand (COD) at sieve rates as high as 160 m³/m²-h. Maximum sieve rate tested was 288 m³/m²-h and maximum particle load was 80 kg TSS/m²-h. When the filter mat on the belt increased from 10 to 55 g TSS/m², the removal efficiency for TSS increased from about 35 to 60%. CEPT is a simple and effective way of increasing the removal efficiency of RBS. Adding about 1 mg/L of cationic polymer and about 2 min of flocculation time, the removal of TSS typically increased from 40–50% without polymer to 60–70% with polymer. Using coagulation and flocculation ahead of the RBS, separation of biofilm solids was successful. Removal efficiencies of 90% TSS, 83% total P and 84% total COD were achieved with a 90 microns belt at a sieve rate of 41 m³/m²-h.

scholarly journals Obtaining filamentous fungi and lipases from sewage treatment plant residue for fat degradation in anaerobic reactors

PeerJ ◽  
2018 ◽  
Vol 6 ◽  
pp. e5368 ◽  
Author(s):  
Anna Cristina P. Lima ◽  
Magali C. Cammarota ◽  
Melissa L.E. Gutarra
Keyword(s):  
Filamentous Fungi ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Oxygen Demand ◽  
Basal Medium ◽  
Primary Treatment ◽  
Lipase Production ◽  
Plant Residue ◽  
Anaerobic Reactors

A residue from the primary treatment of a Wastewater Treatment Plant (WWTP) was used to isolate filamentous fungi with lipase production potential. Two of the 27 isolated fungi presented high hydrolysis index and were selected for lipase production by solid-state fermentation (SSF). The fermentations were conducted at 30 °C for 48 h, with moist air circulation, using 20% (w/w) of the residue mixture with a basal medium (agroindustrial residue—babassu cake), obtaining a solid enzymatic preparation (SEP) with lipase activity of 19 U/g with the fungus identified as Aspergillus terreus. Scum, collected in an anaerobic reactor operating in a WWTP, was hydrolyzed with SEP and subjected to anaerobic biodegradability tests at 30 °C. Different dilutions of crude (Control) or hydrolyzed scum in raw sewage were evaluated. The dilution of 5% (v/v) of hydrolyzed scum in raw sewage proved the most adequate, as it resulted in higher methane yield compared to the raw sewage (196 and 133 mL CH4/g CODadded, respectively), without increasing the chemical oxygen demand (COD) of the treated sewage (138 and 134 mg/L). The enzymatic hydrolysis of the scum, followed by dilution in the influent sewage, is technically feasible and increases methane production in anaerobic reactors.

scholarly journals FOG Waste receiving and processing facility design considerations

2018 ◽  
Vol 13 (1) ◽  
pp. 164-171
Author(s):  
Todd O. Williams ◽  
Dale Gabel ◽  
Dan Robillard
Keyword(s):  
Biogas Production ◽  
Oxygen Demand ◽  
High Strength ◽  
Primary Treatment ◽  
Maximum Energy ◽  
Anaerobic Digesters ◽  
The North ◽  
Chp System ◽  
Processing And Storage ◽  
Number Of Treatment

Abstract Fats, Oils, and Grease (FOG) wastes and high-strength wastes (HSW) are frequently received at municipal water resource recovery facilities (WRRFs) as trucked-in wastes. These wastes offer significant benefits in terms of revenue from tipping fees and feedstock for co-digestion in anaerobic digesters that produce biogas, which can be beneficially used as fuel. The number of treatment plants receiving and beneficially using trucked-in wastes currently in operation or under investigation is increasing rapidly across the North America as utilities strive to remove this material from normal wastewater to avoid sewer system clogging, maintenance and backups, avoid the oxygen demand of these wastes in secondary treatment systems, and to capture and beneficially reuse the energy that is contained within the material. Historically, trucked-in wastes have been discharged to the head end of treatment plants or to an upstream manhole in the incoming interceptor sewer to enable the material to be mixed with raw wastewater prior to treatment through the liquid stream of the WRRF. However, this approach results in loss of material and degradation of the energy value of the FOG wastes and HSW and also creates collection and maintenance issues in the preliminary and primary treatment systems. To prevent degradation of the material and retain maximum energy for the CHP system, receiving stations are being constructed for direct off-loading of the wastes to processing and storage facilities prior to their transfer to anaerobic digesters at a relatively uniform rate to minimize the potential for digester upsets while at the same time to increase biogas production. This paper presents the key components and considerations in the design and operation of modern FOG waste receiving and processing facilities.

scholarly journals Extracellular polymeric substance production in high rate algal oxidation ponds

2017 ◽  
Vol 76 (10) ◽  
pp. 2647-2654 ◽  
Author(s):  
Taobat A. Jimoh ◽  
A. Keith Cowan
Keyword(s):  
Biochemical Analysis ◽  
Suspended Solids ◽  
Extracellular Polymeric Substances ◽  
Sewage Treatment ◽  
Oxygen Demand ◽  
High Rate ◽  
Heterotrophic Metabolism ◽  
Partial Characterisation ◽  
Ft Ir ◽  
Oxidation Ponds

Abstract Integrated algal pond systems (IAPSs) combine anaerobic and aerobic bioprocesses to affect sewage treatment. The present work describes the isolation and partial characterisation of soluble extracellular polymeric substances (EPSs) associated with microalgal bacterial flocs (MaB-flocs) generated in high rate algal oxidation ponds (HRAOPs) of an IAPS treating domestic sewage. Productivity and change in MaB-flocs concentration, measured as mixed liquor suspended solids (MLSS) between morning (MLSSAM) and evening (MLSSPM) were monitored and the substructure of the MaB-flocs matrix examined by biochemical analysis and Fourier transform infrared spectroscopy (FT-IR). Results show that MaB-flocs from HRAOPs are assemblages of microorganisms produced as discrete aggregates as a result of microbial EPS production. Formation and accumulation of the EPS was stimulated by light. Analysis by FT-IR revealed characteristic carbohydrate enrichment of these polymeric substances. In contrast, FT-IR spectra of EPSs from dark-incubated MaB-flocs confirmed that these polymers contained increased aliphatic and aromatic functionalities relative to carbohydrates. These differences, it was concluded, were due to dark-induced transition from phototrophic to heterotrophic metabolism. The results negate microalgal cell death as a contributor to elevated chemical oxygen demand of IAPS treated water.

Wastewater Treatment Operations

2019 ◽  
pp. 89-254
Keyword(s):  
Wastewater Treatment ◽  
Sewage Treatment ◽  
Settling Tank ◽  
Oxygen Demand ◽  
Primary Treatment ◽  
Human Consumption ◽  
Secondary Treatment ◽  
Tertiary Treatment ◽  
Insight Into ◽  
Intended Use

Sewage is treated by a variety of methods to make it suitable for its intended use, be it for spraying onto irrigation fields (for watering crops) or be it for human consumption. Sewage treatment mainly takes place in two main stages: primary and secondary treatment. In arid areas, where there is not enough water, sewage also undergoes a tertiary treatment to meet the demands of the drinking water supply. During primary treatment, the suspended solids are separated from the water and the BOD (biochemical oxygen demand) of the water is reduced, preparing it for the next stage in wastewater treatment. Secondary treatment consists of aeration and settling tank. This process removes 75-95% of the BOD. In case of trickling filter, BOD removal is up to 80%-85%. The water is then disinfected, mostly by chlorination, and released into flowing streams or oceans. Therefore, the main objective of this chapter is to provide a deeper insight into preliminary, primary, secondary, and tertiary treatment of wastewater and furthermore provide cognizance concerning design considerations of treatment units.

Modelling and characterization of primary settlers in view of whole plant and resource recovery modelling

2015 ◽  
Vol 72 (12) ◽  
pp. 2251-2261 ◽  
Author(s):  
Giulia Bachis ◽  
Thibaud Maruéjouls ◽  
Sovanna Tik ◽  
Youri Amerlinck ◽  
Henryk Melcer ◽  
...  
Keyword(s):  
Model Development ◽  
Oxygen Demand ◽  
Resource Recovery ◽  
Primary Treatment ◽  
Model Parameters ◽  
Whole Plant ◽  
Chemically Enhanced Primary Treatment ◽  
Settling Velocity Distribution ◽  
Downstream Processes

Characterization and modelling of primary settlers have been neglected pretty much to date. However, whole plant and resource recovery modelling requires primary settler model development, as current models lack detail in describing the dynamics and the diversity of the removal process for different particulate fractions. This paper focuses on the improved modelling and experimental characterization of primary settlers. First, a new modelling concept based on particle settling velocity distribution is proposed which is then applied for the development of an improved primary settler model as well as for its characterization under addition of chemicals (chemically enhanced primary treatment, CEPT). This model is compared to two existing simple primary settler models (Otterpohl and Freund; Lessard and Beck), showing to be better than the first one and statistically comparable to the second one, but with easier calibration thanks to the ease with which wastewater characteristics can be translated into model parameters. Second, the changes in the activated sludge model (ASM)-based chemical oxygen demand fractionation between inlet and outlet induced by primary settling is investigated, showing that typical wastewater fractions are modified by primary treatment. As they clearly impact the downstream processes, both model improvements demonstrate the need for more detailed primary settler models in view of whole plant modelling.

The impact of chlorine disinfection on biochemical oxygen demand levels in chemically enhanced primary treatment effluent

2013 ◽  
Vol 68 (2) ◽  
pp. 380-386 ◽  
Author(s):  
Ji Dai ◽  
Feng Jiang ◽  
Chii Shang ◽  
Kwok-ming Chau ◽  
Yuet-kar Tse ◽  
...  
Keyword(s):  
Biochemical Oxygen Demand ◽  
Monitoring Program ◽  
Oxygen Demand ◽  
Primary Treatment ◽  
Organic Content ◽  
Injection Point ◽  
Chlorine Disinfection ◽  
Study Results ◽  
Chemically Enhanced Primary Treatment ◽  
The Impact

The response trends of biochemical oxygen demand (BOD) and organic strength after the chlorination/dechlorination process were explored through a 2-year, 5-month chemically enhanced primary treatment (CEPT) effluent onsite monitoring program and a 2-month laboratory-scale study. The monitoring results showed that better instantaneous mixing at the chlorine injection point reduced the effect of chlorination/dechlorination on the 5-day BOD levels. The laboratory study results demonstrated that chlorination did not change the particle size distribution, dissolved organic carbon, or chemical oxygen demand of the organic content of the effluent. Nevertheless, chlorination/dechlorination strongly affected the BOD measurement when nitrification was inhibited by changing bioactivity/biodegradation rates.

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