Continuous treatment of flotation collector wastewater using a membrane bioreactor

2016 ◽  
Vol 73 (8) ◽  
pp. 1901-1909 ◽  
Author(s):  
Weixiong Lin ◽  
Yongkang Dai ◽  
Chun Wu ◽  
Pingting Xu ◽  
Jie Ren ◽  
...  
Keyword(s):  
Activated Sludge ◽  
Extracellular Polymeric Substances ◽  
Tricarboxylic Acid Cycle ◽  
Reduction Rate ◽  
Oxygen Demand ◽  
Continuous Treatment ◽  
Treatment Technology ◽  
Time Period ◽  
Simulated Wastewater ◽  
The Impact

Aniline aerofloat (DDA) is a widely used material in China and has become a main pollutant in floatation wastewater. In this study, a membrane reactor (MBR) was constructed to continuously treat simulated wastewater contaminated with DDA. The study investigated the hydraulic retention time (HRT) and the impact of influent DDA concentration on MBR performance, and analyzed intermediates from the DDA biodegradation pathway and activated sludge transfer pathway. The results showed that a 3 h HRT was an efficient and economical time period for MBR to remove 95 ± 5 mg/L DDA from the simulated wastewater; the chemical oxygen demand reduction rate was 89.9%. DDA concentration negatively impacted MBR performance. MBR performance fluctuated slightly when HRT was 3 h, dissolved oxygen ranged from 4.8 to 5.3 mg/L, pH was between 6.5 and 7.0, and DDA concentrations were at 95 ± 5 mg/L DDA. The transfer pathway in the activated sludge of DDA was through soluble microbial products, loosely bound extracellular polymeric substances, tightly bound extracellular polymeric substances, and finally cell biodegradation. DDA initially degraded to aniline; the aniline was further biodegraded to other organic compounds and was finally mineralized through the tricarboxylic acid cycle. This study offers a new continuous biological treatment technology to address DDA.

scholarly journals Impact of the municipal merger on watershed management: a study of Lake Kasumigaura, Japan

2021 ◽  
Author(s):  
Takeshi Mizunoya ◽  
Noriko Nozaki ◽  
Rajeev Kumar Singh
Keyword(s):  
Watershed Management ◽  
Large Scale ◽  
Environmental Changes ◽  
Water Environment ◽  
Reduction Rate ◽  
Oxygen Demand ◽  
Policy Implications ◽  
Pollution Reduction ◽  
Lake Kasumigaura ◽  
The Impact

AbstractIn the early 2000s, Japan instituted the Great Heisei Consolidation, a national strategy to promote large-scale municipal mergers. This study analyzes the impact that this strategy could have on watershed management. We select the Lake Kasumigaura Basin, the second largest lake in Japan, for the case study and construct a dynamic expanded input–output model to simulate the ecological system around the Lake, the socio-environmental changes over the period, and their mutual dependency for the period 2012–2020. In the model, we regulate and control the following water pollutants: total nitrogen, total phosphorus, and chemical oxygen demand. The results show that a trade-off between economic activity and the environment can be avoided within a specific range of pollution reduction, given that the prefectural government implements optimal water environment policies, assuming that other factors constraining economic growth exist. Additionally, municipal mergers are found to significantly reduce the budget required to improve the water environment, but merger budget efficiency varies nonlinearly with the reduction rate. Furthermore, despite the increase in financial efficiency from the merger, the efficiency of installing domestic wastewater treatment systems decreases drastically beyond a certain pollution reduction level and eventually reaches a limit. Further reductions require direct regulatory instruments in addition to economic policies, along with limiting the output of each industry. Most studies on municipal mergers apply a political, administrative, or financial perspective; few evaluate the quantitative impact of municipal mergers on the environment and environmental policy implications. This study addresses these gaps.

scholarly journals Comparison of the impacts of thermal pretreatment on waste activated sludge using aerobic and anaerobic digestion

2018 ◽  
Vol 78 (8) ◽  
pp. 1772-1781 ◽  
Author(s):  
Hyungjun (Brian) Jo ◽  
Wayne Parker ◽  
Peiman Kianmehr
Keyword(s):  
Anaerobic Digestion ◽  
Activated Sludge ◽  
Oxygen Demand ◽  
Waste Activated Sludge ◽  
Thermal Pretreatment ◽  
Decay Products ◽  
Anaerobic Biodegradability ◽  
Pretreatment Conditions ◽  
The Impact ◽  
Aerobic And Anaerobic

Abstract A range of thermal pretreatment conditions were used to evaluate the impact of high pressure thermal hydrolysis on the biodegradability of waste activated sludge (WAS) under aerobic and anaerobic conditions. It was found that pretreatment did not increase the overall extent to which WAS could be aerobically biodegraded. Thermal pretreatment transformed the biodegradable fraction of WAS (XH) to readily biodegradable chemical oxygen demand (COD) (SB) (16.5–34.6%) and slowly biodegradable COD (XB) (45.8–63.6%). The impact of pretreatment temperature and duration on WAS COD fractionation did not follow a consistent pattern as changes in COD solubilization did not correspond to the observed generation of SB through pretreatment. The pretreated WAS (PWAS) COD fractionations determined from aerobic respirometry were employed in anaerobic modeling and it was concluded that the aerobic and anaerobic biodegradability of PWAS differed. It was found that thermal pretreatment resulted in as much as 50% of the endogenous decay products becoming biodegradable in anaerobic digestion. Overall, it was concluded that the COD fractionation that was developed based upon the aerobic respirometry was valid. However, it was necessary to implement a first-order decay process that reflected changes in the anaerobic biodegradability of the endogenous products through pretreatment.

Use of microtox tests for screening industrial wastewater toxicity

1996 ◽  
Vol 34 (10) ◽  
pp. 43-50 ◽  
Author(s):  
Oliver J. Hao ◽  
Shin Chien-Jen ◽  
Lin Cheng-Fang ◽  
Jeng Fu-Tien ◽  
Chen Zen-Chyuan
Keyword(s):  
Activated Sludge ◽  
Oxygen Demand ◽  
Industrial Wastes ◽  
Wastewater Management ◽  
Waste Discharge ◽  
Significant Toxicity ◽  
Microtox Toxicity ◽  
Microtox Test ◽  
Activated Sludge Processes ◽  
The Impact

Conventional parameters such as chemical oxygen demand and suspended solids may not detect toxic compounds present in a variety of industrial wastewaters and treated wastes. Thus, the presence of toxicity in many industrial wastes presents a significant impact on biological wastewater treatment, and exerts adverse effects on receiving waters. Because of their easy technique and rapid turnaround results, the Microtox tests were used in this study to pinpoint unusual wastewaters, evaluate the toxicity reduction through activated sludge processes, observe the impact of excessive chemical addition to meet the transparency standard, and measure the impact of waste discharge on one particular receiving water. It was found that the results of Microtox tests were useful for such purposes; i.e., low COD wastes exhibited high Microtox toxicity; some activated sludge processes removed significant toxicity; and some effluents from coagulation/oxidation processes showed an increased toxicity. The application of the Microtox test to wastewater management is discussed.

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

Water ◽  
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.

scholarly journals Mathematical modelling of waste activated sludge thermal disintegration

2018 ◽  
Vol 23 ◽  
pp. 00027
Author(s):  
Sylwia Myszograj ◽  
Magdalena Wojciech
Keyword(s):  
Activated Sludge ◽  
Mixed Models ◽  
Treatment Time ◽  
Oxygen Demand ◽  
Repeated Measurements ◽  
Waste Activated Sludge ◽  
Disintegration Time ◽  
Random Factor ◽  
Factor Measurement ◽  
The Impact

Chemical Oxygen Demand (COD) solubilisation was used to evaluate the impact of thermal pretreatment on the transfer of sewage sludge from particulate to soluble phase. It was gathering the experimental data needed for building of empirical mathematical model describing the relation between applied temperature and time and rate of COD solubilisation and degradation. In view of repeated measurements, in order to describe the relationship between changes in the fraction of dissolved COD and the time and temperature, mixed models have been adopted where by fixed factor measurement conditions have been adopted: time and temperature, while the random factor changes the characteristics of waste activated sludge. Linear and logistic nonlinear mixed models were analyzed. The tests demonstrated that all variables are statistically significant in assessing their impact on the efficiency of liquefaction of sludge. On the basis of the estimated model, the temperature rise of 10°C increases degree of disintegration 1.7% above the average treatment time for 0.5h, by 2.6% for 1 hour, and by 3.9% for 2h. COD values decrease between 3 to 23% at temperatures in the range of 55 to 115°C. At higher temperatures COD was reduced in the range of 32 to 44%. Disintegration time did not have the significant impact on the degradation effect.

scholarly journals Multivariate analysis of activated sludge community in full-scale wastewater treatment plants

2020 ◽  
Vol 28 (3) ◽  
pp. 3579-3589
Author(s):  
Mateusz Sobczyk ◽  
Agnieszka Pajdak-Stós ◽  
Edyta Fiałkowska ◽  
Łukasz Sobczyk ◽  
Janusz Fyda
Keyword(s):  
Multivariate Analysis ◽  
Wastewater Treatment ◽  
Activated Sludge ◽  
Community Composition ◽  
Process Parameters ◽  
Wastewater Treatment Plants ◽  
Reduction Rate ◽  
Oxygen Demand ◽  
Principal Component ◽  
Composition Process

AbstractWe investigated changes in protozoa and metazoa community in relation to process parameters in activated sludge from four wastewater treatment plants (WWTPs) throughout the period of 1 year. Principal component analysis (PCA) showed that activated sludge from investigated treatment plants had different dominating species representatives and community composition mainly depends on individual features of the treatment plants. Redundancy analysis (RDA) showed that the temperature in bioreactors was the most relevant factor explaining changes in the microorganism community, whereas reduction rate of chemical oxygen demand (COD), biological oxygen demand (BOD5), suspended solids (SS), and total nitrogen (TN) did not sufficiently explain the variation in protozoa and metazoan community composition. The results indicate that in stable working WWTP it is difficult to find a pronounced link between activated sludge species composition, process parameters, and plant configuration. Applied multivariate analysis can be a valuable tool for the exploration of the relations between community composition and WWTP process parameters.

Modeling of organic substrate transformation in the high-rate activated sludge process

2015 ◽  
Vol 71 (7) ◽  
pp. 971-979 ◽  
Author(s):  
Thomas Nogaj ◽  
Andrew Randall ◽  
Jose Jimenez ◽  
Imre Takacs ◽  
Charles Bott ◽  
...  
Keyword(s):  
Activated Sludge ◽  
Extracellular Polymeric Substances ◽  
Oxygen Demand ◽  
Organic Substrate ◽  
High Rate ◽  
State Variables ◽  
Modified Model ◽  
Soluble Substrate ◽  
Substrate Model ◽  
Dual Substrate

This study describes the development of a modified activated sludge model No.1 framework to describe the organic substrate transformation in the high-rate activated sludge (HRAS) process. New process mechanisms for dual soluble substrate utilization, production of extracellular polymeric substances (EPS), absorption of soluble substrate (storage), and adsorption of colloidal substrate were included in the modified model. Data from two HRAS pilot plants were investigated to calibrate and to validate the proposed model for HRAS systems. A subdivision of readily biodegradable soluble substrate into a slow and fast fraction were included to allow accurate description of effluent soluble chemical oxygen demand (COD) in HRAS versus longer solids retention time (SRT) systems. The modified model incorporates production of EPS and storage polymers as part of the aerobic growth transformation process on the soluble substrate and transformation processes for flocculation of colloidal COD to particulate COD. The adsorbed organics are then converted through hydrolysis to the slowly biodegradable soluble fraction. Two soluble substrate models were evaluated during this study, i.e., the dual substrate and the diauxic models. Both models used two state variables for biodegradable soluble substrate (SBf and SBs) and a single biomass population. The A-stage pilot typically removed 63% of the soluble substrate (SB) at an SRT <0.13 d and 79% at SRT of 0.23 d. In comparison, the dual substrate model predicted 58% removal at the lower SRT and 78% at the higher SRT, with the diauxic model predicting 32% and 70% removals, respectively. Overall, the dual substrate model provided better results than the diauxic model and therefore it was adopted during this study. The dual substrate model successfully described the higher effluent soluble COD observed in the HRAS systems due to the partial removal of SBs, which is almost completely removed in higher SRT systems.

Effect of phosphorus limitation on microbial floc structure and gene expression in activated sludge

2006 ◽  
Vol 54 (1) ◽  
pp. 247-255 ◽  
Author(s):  
J.R. Liu ◽  
C.T. Liu ◽  
E.A. Edwards ◽  
S.N. Liss
Keyword(s):  
Gene Expression ◽  
Activated Sludge ◽  
Extracellular Polymeric Substances ◽  
Morphological Changes ◽  
Cell Structure ◽  
Operating Conditions ◽  
P Limitation ◽  
Floc Structure ◽  
The Impact ◽  
Log Ratio

The effect of limiting phosphorus (P) in activated sludge was investigated in laboratory-scale sequencing batch reactors (SBRs). Correlative microscopy revealed that P-limitation (COD:N:P=100:5:0.05) leads to morphological changes in floc structure and the composition of extracellular polymeric substances (EPS). This was found to be accompanied by expression of quorum-sensing in an acyl homoserine lactone bioassay. Differential gene expression in relation to P-limitation was examined in a global profile using the Affymetrix™ Escherichia coli antisense genomic microarray. Three separate experiments were conducted where the impact of P-limitation was examined under batch conditions and in SBRs at stable operating conditions and within 3–7 days following a down-shift in P. Significant changes in open reading frames (ORF) and intergenic regions based on the E. coli microarray were observed. Several genes associated with cell structure, including slt, wbbH, fimH, amB, rfaJ and slp were found to be expressed. Quorum regulated genes were also found to be expressed including psiF which is known to be induced by P-starvation (92% confidence level; 1.45 log ratio).

Nutrient minimisation in the pulp and paper industry: an overview

2004 ◽  
Vol 50 (3) ◽  
pp. 111-122 ◽  
Author(s):  
A.H. Slade ◽  
R.J. Ellis ◽  
M. van den Heuvel ◽  
T.R. Stuthridge
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Paper Industry ◽  
Pulp And Paper Industry ◽  
Pulp And Paper ◽  
Treated Wastewater ◽  
Nitrogen And Phosphorus ◽  
Treatment Technology ◽  
Solids Separation ◽  
The Impact

This paper reviews nutrient issues within the pulp and paper industry summarising: nitrogen and phosphorus cycles within treatment systems; sources of nutrients within pulping and papermaking processes; minimising nutrient discharge; new approaches to nutrient minimisation; and the impact of nutrients in the environment. Pulp and paper industry wastewaters generally contain insufficient nitrogen and phosphorus to satisfy bacterial growth requirements. Nutrient limitation has been linked to operational problems such as sludge bulking and poor solids separation. Nutrients have been added in conventional wastewater treatment processes to ensure optimum treatment performance. Minimising the discharge of total nitrogen and phosphorus from a nutrient limited wastewater requires both optimised nutrient supplementation and effective removal of suspended solids from the treated wastewater. In an efficiently operated wastewater treatment system, the majority of the discharged nutrients are contained within the biomass. Effective solids separation then becomes the controlling step, and optimisation of secondary clarification is crucial. Conventional practice is being challenged by the regulatory requirement to reduce nitrogen and phosphorus discharge. Two recent developments in pulp and paper wastewater treatment technologies can produce discharges low in nitrogen and phosphorus whilst operating under conventionally nutrient limited conditions: i) the nutrient limited BAS process (Biofilm-Activated Sludge) which combines biofilm and activated sludge technologies under nutrient limited conditions and ii) an activated sludge process based on the use of nitrogen-fixing bacteria. Aerated stabilisation basins often operate without nutrient addition, relying on settled biomass in the benthal zone feeding back soluble nutrients, or the fixation of atmospheric nitrogen. Thus effective nutrient minimisation strategies require a more detailed understanding of nutrient cycling and utilisation. Where it is not possible to meet discharge constraints with biological treatment alone, a tertiary treatment step may be required. In setting nutrient control guidelines, consideration should be given to the nutrient limitations of the receiving environment, including other cumulative nutrient impacts on that environment. Whether an ecosystem is N or P limited should be integrated with wastewater treatment considerations in the further design and development of treatment technology and regulatory guidelines. End-of-pipe legislation alone cannot predict environmental effects related to nutrients and must be supplemented by an effects-based approach.

Evaluating the excess sludge reduction in activated sludge system with ultrasonic treatment

2018 ◽  
Vol 77 (9) ◽  
pp. 2341-2347 ◽  
Author(s):  
Shuang Wu ◽  
Min Zheng ◽  
Qian Dong ◽  
Yanchen Liu ◽  
Chengwen Wang
Keyword(s):  
Activated Sludge ◽  
Ultrasonic Treatment ◽  
Municipal Wastewater ◽  
Oxygen Demand ◽  
Sludge Reduction ◽  
Treatment Technology ◽  
Ph Variation ◽  
Monod Equation ◽  
Soluble Chemical Oxygen Demand ◽  
Excess Sludge Reduction

Abstract Ultrasonic treatment for enhancing biological processes has recently attracted considerable attention in wastewater treatment. In this study, we systematically investigated the mixed liquor properties of activated sludge under ultrasonic treatment. The sludge samples were collected from the aerobic tank of a full-scale membrane bioreactor (MBR) treating municipal wastewater, and the volatile suspended solids (VSS) concentration was approximately 6.0 g/L. The results showed that ultrasonic treatment induced floc disintegration, organics release, temperature increase, microbial activity and pH variation. The maximum mg soluble chemical oxygen demand (COD) per mg VSS released was estimated to be 0.147 using the Monod equation. The exponential increase in the concentration of dissolved organic matter is related to the loss of relative heterotrophic bacterial activity. A sonolysis-cryptic growth model was demonstrated to be capable of describing ultrasonic sludge reduction, which would support the further development of ultrasonic treatment technology in activated sludge systems.

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