The effect of temperature on the efficiency of industrial wastewater nitrification and its (geno)toxicity

AbstractThe paper deals with the problem of the determination of the effects of temperature on the efficiency of the nitrification process of industrial wastewater, as well as its toxicity to the test organisms. The study on nitrification efficiency was performed using wastewater from one of Polish chemical factories. The chemical factory produces nitrogen fertilizers and various chemicals. The investigated wastewater was taken from the influent to the industrial mechanical-biological wastewater treatment plant (WWTP). The WWTP guaranteed high removal efficiency of organic compounds defined as chemical oxygen demand (COD) but periodical failure of nitrification performance was noted in last years of the WWTP operation. The research aim was to establish the cause of recurring failures of nitrification process in the above mentioned WWTP. The tested wastewater was not acutely toxic to activated sludge microorganisms. However, the wastewater was genotoxic to activated sludge microorganisms and the genotoxicity was greater in winter than in spring time. Analysis of almost 3 years’ period of the WWTP operation data and laboratory batch tests showed that activated sludge from the WWTP under study is very sensitive to temperature changes and the nitrification efficiency collapses rapidly under 16°C. Additionally, it was calculated that in order to provide the stable nitrification, in winter period the sludge age (SRT) in the WWTP should be higher than 35 days.

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The impact of slowly biodegradable organic compounds on the oxygen uptake rate in activated sludge systems

Water Science & Technology ◽

10.2166/wst.2013.771 ◽

2013 ◽

Vol 69 (6) ◽

pp. 1136-1144 ◽

Cited By ~ 11

Author(s):

J. Drewnowski

Keyword(s):

Wastewater Treatment ◽

Activated Sludge ◽

Treatment Plant ◽

Oxygen Demand ◽

Oxygen Utilization ◽

Batch Tests ◽

Hydrolysis Process ◽

Major Discrepancy ◽

The Impact ◽

Activated Sludge Systems

The hydrolysis process of slowly biodegradable substrate (XS) has an impact on the efficiencies of nutrient removal in activated sludge systems. Measurement of oxygen utilization rates (OURs) and corresponding chemical oxygen demand (COD) is accepted as a very useful tool to reflect the consumption of biodegradable substrates. The influence of the SS fraction in biological wastewater treatment systems has been extensively investigated, but little information is known about the effects of XS on OUR. The aim of this study was to determine the immediate effects of particulate and colloidal (XS) biodegradable compounds on oxygen utilization for a full-scale process mixed liquor from a large wastewater treatment plant located in northern Poland. Since it is difficult to distinguish XS in a direct way, a novel procedure, based on the standard batch tests, was developed and run in parallel reactors with settled wastewater (SWW) and pretreated SWW samples. Two types of aerobic OUR experiments with low and high substrate/biomass (S0/X0 ratio) concentration, were carried out with the SWW without pretreatment, and pretreated with a coagulation–flocculation (C–F) method. The removal of colloidal and particulate fractions by C–F resulted in reduced process rates. The major discrepancy in the rate reductions (over 300% referred to the OURmax) was observed during the OUR batch test with high S0/X0 ratio.

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

Water Science & Technology ◽

10.2166/wst.2008.232 ◽

2008 ◽

Vol 57 (8) ◽

pp. 1287-1293 ◽

Cited By ~ 1

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 < 30–45 mg l−1 due to the decreased likelihood of methanol overdosing in the denitrification filter

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Evaluating the treatment performance of a full scale Activated Sludge Plant in Islamabad, Pakistan

Water Practice & Technology ◽

10.2166/wpt.2012.016 ◽

2012 ◽

Vol 7 (1) ◽

Cited By ~ 1

Author(s):

S. S. Fatima ◽

S. Jamal Khan

Keyword(s):

Wastewater Treatment ◽

Activated Sludge ◽

Wastewater Treatment Plant ◽

Suspended Solids ◽

Treatment Plant ◽

Oxygen Demand ◽

Full Scale ◽

Operational Parameter ◽

Mixed Liquor ◽

Treatment Performance

In this study, the performance of wastewater treatment plant located at sector I-9 Islamabad, Pakistan, was evaluated. This full scale domestic wastewater treatment plant is based on conventional activated sludge process. The parameters which were monitored regularly included total suspended solids (TSS), mixed liquor suspended solids (MLSS), mixed liquor volatile suspended solids (MLVSS), biological oxygen demand (BOD), and chemical oxygen demand (COD). It was found that the biological degradation efficiency of the plant was below the desired levels in terms of COD and BOD. Also the plant operators were not maintaining consistent sludge retention time (SRT). Abrupt discharge of MLSS through the Surplus Activated sludge (SAS) pump was the main reason for the low MLSS in the aeration tank and consequently low treatment performance. In this study the SRT was optimized based on desired MLSS concentration between 3,000–3,500 mg/L and required performance in terms of BOD, COD and TSS. This study revealed that SRT is a very important operational parameter and its knowledge and correct implementation by the plant operators should be mandatory.

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Enhancing nitrogen removal efficiency in a dyestuff wastewater treatment plant with the IFFAS process: the pilot-scale and full-scale studies

Water Science & Technology ◽

10.2166/wst.2017.522 ◽

2017 ◽

Vol 77 (1) ◽

pp. 70-78 ◽

Cited By ~ 4

Author(s):

Yanjun Mao ◽

Xie Quan ◽

Huimin Zhao ◽

Yaobin Zhang ◽

Shuo Chen ◽

...

Keyword(s):

Wastewater Treatment ◽

Activated Sludge ◽

Removal Efficiency ◽

Nitrogen Removal ◽

Treatment Plant ◽

Oxygen Demand ◽

Pilot Scale ◽

Full Scale ◽

Nitrification And Denitrification ◽

Dyestuff Wastewater

Abstract The activated sludge (AS) process is widely applied in dyestuff wastewater treatment plants (WWTPs); however, the nitrogen removal efficiency is relatively low and the effluent does not meet the indirect discharge standards before being discharged into the industrial park's WWTP. Hence it is necessary to upgrade the WWTP with more advanced technologies. Moving bed biofilm processes with suspended carriers in an aerobic tank are promising methods due to enhanced nitrification and denitrification. Herein, a pilot-scale integrated free-floating biofilm and activated sludge (IFFAS) process was employed to investigate the feasibility of enhancing nitrogen removal efficiency at different hydraulic retention times (HRTs). The results showed that the effluent chemical oxygen demand (COD), ammonium nitrate (NH4+-N) and total nitrogen (TN) concentrations of the IFFAS process were significantly lower than those of the AS process, and could meet the indirect discharge standards. PCR-DGGE and FISH results indicated that more nitrifiers and denitrifiers co-existed in the IFFAS system, promoting simultaneous nitrification and denitrification. Based on the pilot results, the IFFAS process was used to upgrade the full-scale AS process, and the effluent COD, NH4+-N and TN of the IFFAS process were 91–291 mg/L, 10.6–28.7 mg/L and 18.9–48.6 mg/L, stably meeting the indirect discharge standards and demonstrating the advantages of IFFAS in dyestuff wastewater treatment.

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Dynamic control of nutrient-removal from industrial wastewater in a sequencing batch reactor, using common and low-cost online sensors

Water Science & Technology ◽

10.2166/wst.2015.553 ◽

2015 ◽

Vol 73 (4) ◽

pp. 740-745 ◽

Cited By ~ 7

Author(s):

Jan Dries

Keyword(s):

Activated Sludge ◽

Nutrient Removal ◽

Industrial Wastewater ◽

Sequencing Batch Reactor ◽

Batch Reactor ◽

Low Cost ◽

Dynamic Control ◽

Oxygen Demand ◽

Oxidation Reduction ◽

Oxidation Reduction Potential

On-line control of the biological treatment process is an innovative tool to cope with variable concentrations of chemical oxygen demand and nutrients in industrial wastewater. In the present study we implemented a simple dynamic control strategy for nutrient-removal in a sequencing batch reactor (SBR) treating variable tank truck cleaning wastewater. The control system was based on derived signals from two low-cost and robust sensors that are very common in activated sludge plants, i.e. oxidation reduction potential (ORP) and dissolved oxygen. The amount of wastewater fed during anoxic filling phases, and the number of filling phases in the SBR cycle, were determined by the appearance of the ‘nitrate knee’ in the profile of the ORP. The phase length of the subsequent aerobic phases was controlled by the oxygen uptake rate measured online in the reactor. As a result, the sludge loading rate (F/M ratio), the volume exchange rate and the SBR cycle length adapted dynamically to the activity of the activated sludge and the actual characteristics of the wastewater, without affecting the final effluent quality.

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Sensitivity of Effluent Variables in Activated Sludge Process

Chemical Product and Process Modeling ◽

10.1515/cppm-2017-0028 ◽

2017 ◽

Vol 13 (2) ◽

Author(s):

B Vivekanandan ◽

K Jeyannathann ◽

A. Seshagiri Rao

Keyword(s):

Activated Sludge ◽

Flow Rate ◽

Oxygen Transfer Rate ◽

Treatment Plant ◽

Oxygen Demand ◽

Maximum Flow ◽

Activated Sludge Process ◽

Flow Conditions ◽

Treated Effluent ◽

Influent Flow

Abstract The quality of a treated effluent changes when there is a sudden variation in the influent flow to the wastewater treatment plant during dry, rain, and storm weather conditions. In this study, various influent flow conditions in an activated sludge process are considered that affect the sensitivity of effluent variables such as chemical oxygen demand (COD), biological oxygen demand (BOD), nitrate nitrogen (SNO), ammonical nitrogen (SNH), and total nitrogen (TN) with respect to varying internal recycle flow rate (Qa), sludge recycle flow rate (Qr), sludge wastage flow rate (Qw) and oxygen transfer rate co-efficient of aerobic tanks (KLa(3,4,5)). The analysis has been carried out based on benchmark simulation model no.1 (BSM 1) plant layout which comprises of two models namely activated sludge model no.1 (ASM 1) and simple one dimensional (Simple 1-D) Takacs model. Based on the present analysis, it is observed that the changes in influent flow rate have larger impact on the effluent variables. This variation can be subdued by introducing additional tanks to smoothen the perturbations or using internal recycle rate from the fifth tank in order to maintain the flow around the optimal influent flow rate. The sludge wastage rate has a greater impact on all effluent variables except nitrogenous variables during maximum flow conditions.

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Removal of Oxygen Demand and Acute Toxicity during Batch Biological Treatment of a Petroleum Refinery Effluent

Water Quality Research Journal ◽

10.2166/wqrj.2002.026 ◽

2002 ◽

Vol 37 (2) ◽

pp. 399-411 ◽

Cited By ~ 10

Author(s):

Brihas P. Sarathy ◽

Preston M. Hoy ◽

Sheldon J.B. Duff

Keyword(s):

Biological Treatment ◽

Petroleum Refinery ◽

Treatment Plant ◽

Oxygen Demand ◽

Refinery Effluent ◽

Second Stage ◽

Batch Tests ◽

Microtox Toxicity ◽

Petroleum Refinery Effluent ◽

Two Stages

Abstract A survey of the process streams at an operating petroleum refinery showed that desalting water from the crude and splitter units had the highest concentrations of pollutants, and accounted for approximately one-third of the BOD and COD of the combined effluent. Combined effluent (234 ± 62 mg BOD/L, 510 ± 0 mg COD/L, and Microtox EC50 4.9 ± 0.4%) was treated using a laboratory-scale batch biological reactor. Ninety-three percent of BOD and 77% of COD were removed over the first 24 hours of biological treatment. Acute (Microtox) toxicity was reduced in two discrete stages; the first coinciding with BOD and COD removal and the second stage occurring after BOD and COD had been removed. A final EC50 value of 27.8% was achieved in batch tests. The two stages of toxicity removal correspond quantitatively to the toxicity removal observed during secondary and tertiary biological treatment at the petroleum refinery's full-scale wastewater treatment plant.

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The Impact of Selected Parameters on the Condition of Activated Sludge in a Biologic Reactor in the Treatment Plant in Nowy Targ, Poland

Water ◽

10.3390/w12102657 ◽

2020 ◽

Vol 12 (10) ◽

pp. 2657

Author(s):

Elwira Nowobilska-Majewska ◽

Piotr Bugajski

Keyword(s):

Wastewater Treatment ◽

Statistical Analysis ◽

Activated Sludge ◽

Partial Correlation ◽

Oxygen Uptake Rate ◽

Treatment Plant ◽

Oxygen Demand ◽

Test Results ◽

Partial Correlation Analysis ◽

The Impact

The aim of this study was to determine the condition of activated sludge in the biologic reactor located in the collective wastewater treatment plant in Nowy Targ (Poland) based on OUR tests in the aspect of the impact of sludge’s concentration in the biologic reactor and dependence of BOD5/TN and BOD5/TP in wastewater flowing into the biologic reactor. The analysis was conducted based on test results from 61 samples of activated sludge taken from the biologic reactor and 61 samples of wastewater flowing into the biologic reactor. The analysis included the concentration of sludge in the biologic reactor. The following indicators were analyzed in wastewater flowing into the reactor: biochemical oxygen demand (BOD5), total nitrogen (TN) and total phosphorus (TP). The statistical analysis concerning the impact of the analyzed factors on oxygen uptake rate (OUR) tests was developed based on the Pearson’s correlation coefficient and partial correlation of many variables. Based on the results of the partial correlation analysis, nomograms were developed to determine the condition of activated sludge microorganisms (OUR) based on the BOD5/TN and BOD5/TP connection and knowledge of the sludge concentration in the bioreactor of the treatment plant. The presented nomograms can be formulated for each bioreactor based on activated sludge technology related the load of organic and biogenic pollutants in the wastewater flowing into the bioreactor and the concentration of the sludge in the bioreactor.

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OPTIMISATION OF W ASTEW A TER TREATMENT PLANTS BY MEANS OF COMPUTER MODELS

Water Science & Technology ◽

10.2166/wst.1994.0186 ◽

1994 ◽

Vol 30 (4) ◽

pp. 181-190 ◽

Cited By ~ 3

Author(s):

René Dupont ◽

Ole Sinkjær

Keyword(s):

Wastewater Treatment ◽

Activated Sludge ◽

Pilot Plant ◽

Wastewater Treatment Plants ◽

Treatment Plant ◽

Operational Strategies ◽

Nitrification Process ◽

Computer Based ◽

Calibration Tool ◽

Denitrification Process

The objective of the work presented is to demonstrate how computer based models can be used to improve the effluent quality from wastewater treatment plants by optimisation of the operation. The investigation was carried out in connection with pilot plant investigations at Damhusllen Wastewater Treatment Plant in order to establish the design basis for upgrading the treatment plants in the city of Copenhagen. Calibration of the model was done with thorough characterisation of the wastewater and the activated sludge as the primary calibration tool. Special attention was paid to the nitrification process, which by previous investigations was shown to be occasionally inhibited. Model constants for the nitrification process were detennined from experiments. Default constants were used for nearly all other constants. The pilot plant was optimized with the calibrated model. Different operational strategies for improvement of the denitrification process were tested. The denitrification process was operated relatively poorly at the time for the optimisation. The calibration showed that it was possible to calibrate the model using the characterization of the wastewater and the activated sludge as the primary calibration tool. Further it was shown that the calihrated model could be used as a tool for optimising the operation of the pilot plant. The suggested operation correlated well with the practical realisable operation.

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Using metazoa to reduce sludge production

Water Science & Technology ◽

10.2166/wst.1997.0408 ◽

1997 ◽

Vol 36 (11) ◽

pp. 171-179 ◽

Cited By ~ 29

Author(s):

J. H. Rensink ◽

W. H. Rulkens

Keyword(s):

Wastewater Treatment ◽

Activated Sludge ◽

Wastewater Treatment Plants ◽

Treatment Plant ◽

Domestic Wastewater ◽

Brewery Wastewater ◽

Trickling Filters ◽

Starting Point ◽

Nitrification Process ◽

Sludge Production

Pilot plant experiments have been carried out to study the mineralization of sludge from biological wastewater treatment plants by worms such as Tubificidae. Trickling filters filled with lava slags were continuously fed with a certain quantity of excess activated sludge of a Dutch brewery wastewater treatment plant (Bavaria) by recirculation during 10 to 14 days. At the starting point of each experiment the trickling filters were inoculated with Tubificidae. Recirculation of sludge showed that use of Tubificidae resulted in a COD reduction of the sludge (mixed liquor) of 18–67–. Without worms this reduction was substantially lower. The sludge production in a pilot activated sludge system for treating settled domestic wastewater reduced from 0.40 to 0.15 g MLSS/g COD removed when Tubificidae were added to the system. The lower amounts of sludge were always accompanied by an increase of nitrate and phosphate concentration in the wastewater. There was no disturbance of the nitrification process. Application of Tubificidae or other worms may have interesting potential for practical application.

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