scholarly journals Evaluation of Partial Nitritation/Anammox (PN/A) Process Performance and Microorganisms Community Composition under Different C/N Ratio

Water ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 2270 ◽  
Author(s):  
Hussein Al-Hazmi ◽  
Dominika Grubba ◽  
Joanna Majtacz ◽  
Przemyslaw Kowal ◽  
Jacek Makinia
Keyword(s):  
Oxygen Demand ◽  
Domestic Wastewater ◽  
Process Efficiency ◽  
Utilization Rate ◽  
Gradual Change ◽  
Partial Nitritation ◽  
Aeration Time ◽  
Heterotrophic Metabolism ◽  
High Chemical Oxygen Demand ◽  
Intensive Growth

A one-stage partial nitritation/anammox (PN/A) process with intermittent aeration is possible under sidestream conditions, but implementation in a mainstream is a challenge due to increased Carbon/Nitrogen (C/N) ratios in domestic wastewater. This study investigated the effect of C/N ratios on process efficiency and the effect of narrowing non-aeration time on process improvement at high chemical oxygen demand (COD) load. An increase in TN removal efficiency was achieved in both series with gradual change of C/N ratio from 1 to 3, from 65.1% to 83.4% and 63.5% to 78% in 1st and 2nd series, respectively. However, at the same time, the ammonium utilization rate (AUR) value decreased with the increase in C/N ratio. At a high COD (C/N = 3) concentration, the process broke down and regained productivity after narrowing the non-aeration time in both series. Shifts in the system performance were also connected to adaptive changes in microbial community revealed by data obtained from 16S rRNA NGS (next-generation sequencing), which showed intensive growth of the bacteria with dominant heterotrophic metabolism and the decreasing ratio of autotrophic bacteria. The study shows that deammonification is applicable to the mainstream provided that the C/N ratio and the aeration/non-aeration time are optimized.

scholarly journals An integrated process of methanol coagulation and side-stream membrane bioreactor for the treatment of rice gruel wastewater

2021 ◽  
Author(s):  
Shaik Nazia ◽  
Karishma Mishra ◽  
Veeriah Jegatheesan ◽  
Suresh K Bhargava ◽  
Sridhar Sundergopal
Keyword(s):  
Membrane Bioreactor ◽  
Oxygen Demand ◽  
Domestic Wastewater ◽  
Cost Effective ◽  
Process Efficiency ◽  
Separation Performance ◽  
Integrated Process ◽  
Efficient Treatment ◽  
Environmentally Safe ◽  
Small Footprint

Abstract The demand for water supply is increasing rapidly across the world due to the exponential growth of population, swift urbanization, and industrialization. Methods for recovery of reusable water from domestic, industrial and agricultural wastewater should be cost-effective, and environmentally safe for the sustainability of water resources. Domestic wastewater is one of the contaminated water sources which need efficient treatment before discharge into water bodies. The novelty of the present study is to treat domestic rice gruel wastewater by coagulation integrated aerobic membrane bioreactor (AMBR) for the generation of reusable water. A hydrophilized ultrafiltration (HF-UF) spiral wound membrane of 5 kDa molecular weight cut off was used for the treatment of rice gruel wastewater at a feed temperature of 30 °C and 80 °C to study separation performance. Further, a comparison study was carried using various coagulants such as methanol, ethanol, and HCl for integration with HF-UF membrane to determine overall process efficiency at 30 °C. Methanol coagulation + HF-UF membrane based integrated process was able to achieve 93.77%, 95.4%, 91%, and 78.6 %, respectively of total dissolved solids (TDS), turbidity, conductivity, and chemical oxygen demand (COD). Further, this process was integrated with a bioreactor operated under aerobic conditions to improve the process efficiency and purified water quality. From the overall experimental results, the integrated coagulation + AMBR process attained a maximum removal of 93.9, 96, 91, and 94.6 percent of TDS, turbidity, conductivity and COD, correspondingly. Finally, an economic estimation of a 1000 Lh-1 capacity pilot plant is described in detail. The study depicts unique advantages of economy, process safety, small footprint, and eco-friendly for rice gruel wastewater by a combination of chemical coagulation with AMBR.

scholarly journals Confirmation the optimal aeration parameters for nitrogen removal and nitrous oxide emission in wastewater ecological soil infiltration systems with brown earth

2019 ◽  
Vol 80 (1) ◽  
pp. 144-152 ◽  
Author(s):  
Yafei Sun ◽  
Junling Pang ◽  
Shiyao Wang ◽  
Tingting Tao ◽  
Xun Fu ◽  
...  
Keyword(s):  
Nitrous Oxide ◽  
Nitrogen Removal ◽  
Emission Rate ◽  
Oxygen Demand ◽  
Domestic Wastewater ◽  
N2o Emission ◽  
Aeration Rate ◽  
Soil Infiltration ◽  
Aeration Time ◽  
Domestic Wastewater Treatment

Abstract Nitrogen removal is an obstacle for the wide application of wastewater ecological soil infiltration (WESI) system in domestic wastewater treatment. In this study, matrix dissolved oxygen (DO), nitrogen removal and nitrous oxide (N2O) emission in aerated pilot WESI systems were investigated under different aeration times (1, 2, 3, 4 and 6 h/d) and aeration rates (1, 2, 3 and 4 L/min). The results showed that aerobic conditions in upper matrix and anoxic or anaerobic conditions in the subsequent matrix were developed in an aerated/non-aerated cycle at the optimal aeration condition of aeration time of 4 h/d and aeration rate of 3 L/min. Simultaneously, high removal efficiency of chemical oxygen demand (COD) (97.9%), NH4+-N (98.2%), total nitrogen (TN) (90.7%) and low N2O emission rate (13.2 mg/(m2 d)) were obtained. The results would provide optimal aeration parameters for application of intermittent aerated WESI systems.

scholarly journals Anaerobic hydrolysis of complex substrates in full-scale aerobic granular sludge: enzymatic activity determined in different sludge fractions

2021 ◽  
Author(s):  
Sara Toja Ortega ◽  
Mario Pronk ◽  
Merle K. de Kreuk
Keyword(s):  
Hydrolytic Enzymes ◽  
Oxygen Demand ◽  
Domestic Wastewater ◽  
Granular Sludge ◽  
Hydrolytic Activity ◽  
Full Scale ◽  
Aerobic Granular Sludge ◽  
Bulk Liquid ◽  
Granule Formation ◽  
Hydrolysis Of

Abstract Complex substrates, like proteins, carbohydrates, and lipids, are major components of domestic wastewater, and yet their degradation in biofilm-based wastewater treatment technologies, such as aerobic granular sludge (AGS), is not well understood. Hydrolysis is considered the rate-limiting step in the bioconversion of complex substrates, and as such, it will impact the utilization of a large wastewater COD (chemical oxygen demand) fraction by the biofilms or granules. To study the hydrolysis of complex substrates within these types of biomass, this paper investigates the anaerobic activity of major hydrolytic enzymes in the different sludge fractions of a full-scale AGS reactor. Chromogenic substrates were used under fully mixed anaerobic conditions to determine lipase, protease, α-glucosidase, and β-glucosidase activities in large granules (>1 mm in diameter), small granules (0.2–1 mm), flocculent sludge (0.045–0.2 mm), and bulk liquid. Furthermore, composition and hydrolytic activity of influent wastewater samples were determined. Our results showed an overcapacity of the sludge to hydrolyze wastewater soluble and colloidal polymeric substrates. The highest specific hydrolytic activity was associated with the flocculent sludge fraction (1.5–7.5 times that of large and smaller granules), in agreement with its large available surface area. However, the biomass in the full-scale reactor consisted of 84% large granules, making the large granules account for 55–68% of the total hydrolytic activity potential in the reactor. These observations shine a new light on the contribution of large granules to the conversion of polymeric COD and suggest that large granules can hydrolyze a significant amount of this influent fraction. The anaerobic removal of polymeric soluble and colloidal substrates could clarify the stable granule formation that is observed in full-scale installations, even when those are fed with complex wastewaters. Key points • Large and small granules contain >70% of the hydrolysis potential in an AGS reactor. • Flocculent sludge has high hydrolytic activity but constitutes <10% VS in AGS. • AGS has an overcapacity to hydrolyze complex substrates in domestic wastewater. Graphical abstract

scholarly journals A Preliminary Study on the Use of Xylit as Filter Material for Domestic Wastewater Treatment

2021 ◽  
Vol 11 (11) ◽  
pp. 5281
Author(s):  
Marcin Spychała ◽  
Tadeusz Nawrot ◽  
Radosław Matz
Keyword(s):  
Quality Indicators ◽  
Initial Period ◽  
Oxygen Demand ◽  
Domestic Wastewater ◽  
Filter Material ◽  
Stage I ◽  
Stage Ii ◽  
Septic Tank ◽  
Preliminary Stage ◽  
Wastewater Quality

The aim of the study was to verify two morphological forms (“angel hair” and “scraps”) of xylit as a trickling filter material. The study was carried out on two types of polluted media: septic tank effluent (STE) and seminatural greywater (GW). The basic wastewater quality indicators, namely, chemical oxygen demand (COD), biochemical oxygen demand (BOD5), total suspended solids (TSS), ammonium nitrogen (NNH4), and total phosphorus (Ptot) were used as the indicators of treatment efficiency. Filtering columns filled with the investigated material acted as conventional trickling filters at a hydraulic load of 376–472 cm3/d during the preliminary stage, 198–245 cm3/d during stage I, and 184–223 cm3/d during stage II. The removal efficiency of the two morphological forms of xylit did not differ significantly. The average efficiencies of treatment were as follows: for COD, over 70, 80, and 85% for preliminary stage, stage I and stage II, respectively; for BOD5, 77–79% (preliminary stage); for TSS, 42% and 70% during the preliminary stage, and 88, 91, and 65% during stage I; for NNH4, 97–99% for stage I and 36–49% for stage II; for Ptot, 51–54% for stage I and 52–56% for stage II. The study demonstrated that xylit was a material highly effective in wastewater quality indicators removal, even during the initial period of its use.

scholarly journals Efficiency and Technological Reliability of Contaminant Removal in Household WWTPs with Activated Sludge

2021 ◽  
Vol 11 (4) ◽  
pp. 1889 ◽  
Author(s):  
Agnieszka Micek ◽  
Krzysztof Jóźwiakowski ◽  
Michał Marzec ◽  
Agnieszka Listosz ◽  
Tadeusz Grabowski
Keyword(s):  
Activated Sludge ◽  
Wastewater Treatment Plants ◽  
Oxygen Demand ◽  
Domestic Wastewater ◽  
Pollutant Removal ◽  
Treated Wastewater ◽  
Contaminant Removal ◽  
Nitrogen And Phosphorus ◽  
Wastewater Samples ◽  
Polish Law

The results of research on the efficiency and technological reliability of domestic wastewater purification in two household wastewater treatment plants (WWTPs) with activated sludge are presented in this paper. The studied facilities were located in the territory of the Roztocze National Park (Poland). The mean wastewater flow rate in the WWTPs was 1.0 and 1.6 m3/day. In 2017–2019, 20 series of analyses were done, and 40 wastewater samples were taken. On the basis of the received results, the efficiency of basic pollutant removal was determined. The technological reliability of the tested facilities was specified using the Weibull method. The average removal efficiencies for the biochemical oxygen demand in 5 days (BOD5) and chemical oxygen demand (COD) were 66–83% and 62–65%, respectively. Much lower effects were obtained for total suspended solids (TSS) and amounted to 17–48%, while the efficiency of total phosphorus (TP) and total nitrogen (TN) removal did not exceed 34%. The analyzed systems were characterized by the reliability of TSS, BOD5, and COD removal at the level of 76–96%. However, the reliability of TN and TP elimination was less than 5%. Thus, in the case of biogenic compounds, the analyzed systems did not guarantee that the quality of treated wastewater would meet the requirements of the Polish law during any period of operation. This disqualifies the discussed technological solution in terms of its wide application in protected areas and near lakes, where the requirements for nitrogen and phosphorus removal are high.

Savings with upgraded performance through improved activated sludge denitrification in the combined activated sludge–biofilter system of the Southpest Wastewater Treatment Plant

2008 ◽  
Vol 57 (8) ◽  
pp. 1287-1293 ◽  
Author(s):  
A. Jobbágy ◽  
G. M. Tardy ◽  
Gy. Palkó ◽  
A. Benáková ◽  
O. Krhutková ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Wastewater Treatment Plant ◽  
Biological Treatment ◽  
Treatment Plant ◽  
Oxygen Demand ◽  
Process Efficiency ◽  
Initial Value ◽  
Initial Profile ◽  
Biological Treatment System

The purpose of the experiments was to increase the rate of activated sludge denitrification in the combined biological treatment system of the Southpest Wastewater Treatment Plant in order to gain savings in cost and energy and improve process efficiency. Initial profile measurements revealed excess denitrification capacity of the preclarified wastewater. As a consequence, flow of nitrification filter effluent recirculated to the anoxic activated sludge basins was increased from 23,000 m3 d−1 to 42,288 m3 d−1 at an average preclarified influent flow of 64,843 m3 d−1, Both simulation studies and microbiological investigations suggested that activated sludge nitrification, achieved despite the low SRT (2–3 days), was initiated by the backseeding from the nitrification filters and facilitated by the decreased oxygen demand of the influent organics used for denitrification. With the improved activated sludge denitrification, methanol demand could be decreased to about half of the initial value. With the increased efficiency of the activated sludge pre-denitrification, plant effluent COD levels decreased from 40–70 mg l−1 to &lt; 30–45 mg l−1 due to the decreased likelihood of methanol overdosing in the denitrification filter

scholarly journals Treatment performances of French constructed wetlands: results from a database collected over the last 30 years

2015 ◽  
Vol 71 (9) ◽  
pp. 1333-1339 ◽  
Author(s):  
A. Morvannou ◽  
N. Forquet ◽  
S. Michel ◽  
S. Troesch ◽  
P. Molle
Keyword(s):  
Constructed Wetlands ◽  
Oxygen Demand ◽  
Pollutant Removal ◽  
Vertical Flow ◽  
Removal Rates ◽  
Waste Stabilization Ponds ◽  
Small Communities ◽  
Technical Department ◽  
In Series ◽  
High Chemical Oxygen Demand

Approximately 3,500 constructed wetlands (CWs) provide raw wastewater treatment in France for small communities (&lt;5,000 people equivalent). Built during the past 30 years, most consist of two vertical flow constructed wetlands (VFCWs) in series (stages). Many configurations exist, with systems associated with horizontal flow filters or waste stabilization ponds, vertical flow with recirculation, partially saturated systems, etc. A database analyzed 10 years earlier on the classical French system summarized the global performances data. This paper provides a similar analysis of performance data from 415 full-scale two-stage VFCWs from an improved database expanded by monitoring data available from Irstea and the French technical department. Trends presented in the first study are confirmed, exhibiting high chemical oxygen demand (COD), total suspended solids (TSS) and total Kjeldahl nitrogen (TKN) removal rates (87%, 93% and 84%, respectively). Typical concentrations at the second-stage outlet are 74 mgCOD L−1, 17 mgTSS L−1 and 11 mgTKN L−1. Pollutant removal performances are summarized in relation to the loads applied at the first treatment stage. While COD and TSS removal rates remain stable over the range of applied loads, the spreading of TKN removal rates increases as applied loads increase.

Two-stage entrapped mixed microbial cell process for simultaneous removal of organics and nitrogen for rural domestic sewage application

2004 ◽  
Vol 49 (5-6) ◽  
pp. 281-288 ◽  
Author(s):  
S.J. Kim ◽  
P.Y. Yang
Keyword(s):  
Removal Efficiency ◽  
Loading Rate ◽  
Oxygen Demand ◽  
Domestic Wastewater ◽  
Microbial Cell ◽  
Two Stage ◽  
Rate Limiting Step ◽  
Soluble Chemical Oxygen Demand ◽  
Removal Efficiencies ◽  
Entrapped Mixed Microbial Cell

A two-stage entrapped mixed microbial cell (2SEMMC) process which separates nitrification and denitrification phases by the installation of the anoxic and oxic EMMC reactors packed with EMMC carriers was operated with 6, 4, 3, and 2 hours of hydraulic retention time (HRT) using simulated domestic wastewater. The activated sludge was immobilized using cellulose acetate for the EMMC carriers. Similar soluble chemical oxygen demand (SCOD) removal efficiencies of 90-97% were observed for all HRTs (SCOD loading rate of 0.84-2.30 g/L/d) applied. In order to achieve more than 80 % of TN removal efficiency, the HRT should be maintained higher than 4 hours (less than 0.24 g/L/d of TN loading rate). Denitrification was a rate-limiting step which controlled overall TN removal efficiency at TN loading rate of 0.15-0.31 g/L/d although nitrification efficiencies achieved 97-99 %. The effluent TSS of less than 25 mg/L in the 2SEMMC process was maintained at the SCOD loading rate of less than 1.23 g/L/d with back-washing intervals of 5 and 10 days in the anoxic and oxic EMMC reactors, respectively. The minimum HRT of 4 hours is required for high removal efficiencies of organics (average 95.6 %) and nitrogen (average 80.5 %) in the 2SEMMC process with 3 times of recirculation ratio.

Degradation of wine distillery wastewaters by the combination of aerobic biological treatment with chemical oxidation by Fenton's reagent

2005 ◽  
Vol 51 (1) ◽  
pp. 167-174 ◽  
Author(s):  
J. Beltran de Heredia ◽  
J. Torregrosa ◽  
J.R. Dominguez ◽  
E. Partido
Keyword(s):  
Chemical Oxygen Demand ◽  
Aromatic Compounds ◽  
Biological Treatment ◽  
Batch Reactor ◽  
Oxygen Demand ◽  
Chemical Oxidation ◽  
Utilization Rate ◽  
Fenton’S Reagent ◽  
Kinetic Rate Constant ◽  
Fenton's Reagent

The degradation of wine distillery wastewaters by aerobic biological treatment has been investigated in a batch reactor. The evolution of the chemical oxygen demand, biomass and total contents of polyphenolic and aromatic compounds was followed through each experiment. According to the Contois model, a kinetic expression for the substrate utilization rate is derived, and its biokinetic constant is evaluated. The final effluents of the aerobic biological experiments were oxidized by Fenton's reagent. The evolution of chemical oxygen demand, hydrogen peroxide concentration and total contents of polyphenolic and aromatic compounds was followed through each experiment. A kinetic model to interpret the experimental data is proposed. The kinetic rate constant of the global reaction is determined.

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