Behaviour of volatile and nonvolatile suspended solids in the pilot-scale aerobic digestion of waste-activated sludges

1993 ◽  
Vol 20 (1) ◽  
pp. 22-36 ◽  
Author(s):  
B. C. Anderson ◽  
D. S. Mavinic
Keyword(s):  
Suspended Solids ◽  
Ph Control ◽  
Pilot Scale ◽  
Operating Conditions ◽  
Inorganic Materials ◽  
Aerobic Digestion ◽  
Simple Method ◽  
Mixed Liquor ◽  
Sludge Digestion ◽  
Naturally Occurring

Pilot-scale research into the characterization and enhancement of the aerobic digestion of waste-activated sludges was performed. Waste sludge from two sources was aerobically digested at varying operating temperatures; to offset the naturally occurring mixed liquor pH (MLpH) decrease due to nitrification, small amounts of Ca(OH)2 or NaHCO3 were added to maintain target MLpH levels of pH 6, 7, and 8. Results indicated that volatile mass reduction was severely curtailed at low MLpH, but could be significantly improved through MLpH control, with increases of > 100% in performance over the low MLpH reactor noted. However, the process was found to be very "sludge-specific", in that the two test sludges behaved quite differently under similar operating conditions. A separate mass balance on the nonvolatile sludge fraction illustrated the action of the controlling chemicals in terms of reduction in cell lysis; it was also observed that some precipitation of inorganic materials was occurring, depending on chemical type and dose. While it was not possible to suggest an optimized chemical and dose, it was concluded that this process had very real potential for full-scale implementation, as an effective and simple method for rehabilitation of poorly functioning digesters. Key words: aerobic sludge digestion, Ca(OH)2, enhancement, inhibition, mixed liquor pH control, NaHCO3, volatile and nonvolatile suspended solids.

scholarly journals Co-treatment of old landfill leachate and municipal wastewater in sequencing batch reactor (SBR): effect of landfill leachate concentration

2016 ◽  
Vol 51 (4) ◽  
pp. 377-387 ◽  
Author(s):  
Kshitij Ranjan ◽  
Shubhrasekhar Chakraborty ◽  
Mohini Verma ◽  
Jawed Iqbal ◽  
R. Naresh Kumar
Keyword(s):  
Removal Efficiency ◽  
Landfill Leachate ◽  
Suspended Solids ◽  
Sequencing Batch Reactor ◽  
Municipal Wastewater ◽  
Batch Reactor ◽  
Operating Conditions ◽  
Volume Index ◽  
Turbidity Removal ◽  
Mixed Liquor

Sequencing batch reactor (SBR) was assessed for direct co-treatment of old landfill leachate and municipal wastewater for chemical oxygen demand (COD), nutrients and turbidity removal. Nitrogen removal was achieved by sequential nitrification and denitrification under post-anoxic conditions. Initially, SBR operating conditions were optimized by varying hydraulic retention time (HRT) at 20% (v/v) landfill leachate concentration, and results showed that 6 d HRT was suitable for co-treatment. SBR performance was assessed in terms of COD, ammonia, nitrate, phosphate, and turbidity removal efficiency. pH, mixed liquor suspended solids, mixed liquor volatile suspended solids (MLVSS), and sludge volume index were monitored to evaluate stability of SBR. MLVSS indicated that biomass was able to grow even at higher concentrations of old landfill leachate. Ammonia and nitrate removal efficiency was more than 93% and 83%, respectively, whereas COD reduction was in the range of 60–70%. Phosphate and turbidity removal efficiency was 80% and 83%, respectively. Microbial growth kinetic parameters indicated that there was no inhibition of biomass growth up to 20% landfill leachate. The results highlighted that SBR can be used as an initial step for direct co-treatment of landfill leachate and municipal wastewater.

scholarly journals The treatment of solvent recovery raffinate by aerobic granular sludge in a pilot-scale sequencing batch reactor

2015 ◽  
Vol 13 (3) ◽  
pp. 746-757 ◽  
Author(s):  
Bei Long ◽  
Chang-zhu Yang ◽  
Wen-hong Pu ◽  
Jia-kuan Yang ◽  
Guo-sheng Jiang ◽  
...  
Keyword(s):  
Suspended Solids ◽  
Sequencing Batch Reactor ◽  
Batch Reactor ◽  
Granular Sludge ◽  
Pilot Scale ◽  
Volume Index ◽  
Aerobic Granular Sludge ◽  
Average Particle ◽  
Solvent Recovery ◽  
Mixed Liquor

Mature aerobic granular sludge (AGS) was inoculated for the start-up of a pilot-scale sequencing batch reactor for the treatment of high concentration solvent recovery raffinate (SRR). The proportion of simulated wastewater (SW) (w/w) in the influent gradually decreased to zero during the operation, while volume of SRR gradually increased from zero to 10.84 L. AGS was successfully domesticated after 48 days, which maintained its structure during the operation. The domesticated AGS was orange, irregular, smooth and compact. Sludge volume index (SVI), SV30/SV5, mixed liquor volatile suspended solids/mixed liquor suspended solids (MLVSS/MLSS), extracellular polymeric substances, proteins/polysaccharides, average particle size, granulation rate, specific oxygen utilization rates (SOUR)H and (SOUR)N of AGS were about 38 mL/g, 0.97, 0.52, 39.73 mg/g MLVSS, 1.17, 1.51 mm, 96.66%, 47.40 mg O2/h g volatile suspended solids (VSS) and 8.96 mg O2/h g VSS, respectively. Good removal effect was achieved by the reactor. Finally, the removal rates of chemical oxygen demand (COD), total inorganic nitrogen (TIN), NH4+-N and total phosphorus (TP) were more than 98%, 96%, 97% and 97%, respectively. The result indicated gradually increasing the proportion of real wastewater in influent was a useful domestication method, and the feasibility of AGS for treatment of high C/N ratio industrial wastewater.

scholarly journals The influence of operating conditions of activated-sludge treatment on the behaviour of f2 coliphage

1979 ◽  
Vol 82 (2) ◽  
pp. 285-291 ◽  
Author(s):  
S. A. Balluz ◽  
M. Butler
Keyword(s):  
High Temperature ◽  
Activated Sludge ◽  
Suspended Solids ◽  
Operating Conditions ◽  
Regression Coefficients ◽  
Sludge Treatment ◽  
Mixed Liquor ◽  
Treatment Conditions ◽  
Solids Concentration ◽  
Flow Through

SUMMARYThe behaviour of f2 coliphage during activated-sludge treatment was influenced by the temperature, flow-through-time, concentration of mixed liquor suspended solids and the virus load.The most sensitive way to detect behavioural changes was to examine the regression coefficients for the rate of uptake or loss of virus by the mixed liquor solids. This type of analysis revealed, for instance, high values when the solids concentration was high and even greater values occured when high inocula were used. At high temperature the rate of loss of virus titre after inoculation had stopped was greater than the rate of uptake of virus during inoculation although in all other conditions uptake occurred at a greater rate than the loss of virus. The coefficients were relatively low when the flow rate was increased, when the temperature was low or when the inoculum was small.The distribution of virus between the solids and liquid fractions of the mixed liquor varied somewhat for all conditions but was notably different when (a) the plant was incubated at 5 °C when there was much less virus in the solids fraction than usual, and (b) when the inoculum was low and a much higher proportion of virus was found in the solids.The efficiency with which virus was removed across the plant was the least-sensitive determinant of viral behaviour and the value was about the same for most treatment conditions. However, low or high inocula did result in some increased or decreased removal of virus, respectively.

scholarly journals Effect of Operating Conditions on Membrane Fouling in Pilot-Scale MBRs; Filaments Growth, Diminishing Dissolved Oxygen and Recirculation Rate of the Activated Sludge

Membranes ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 490
Author(s):  
Petros Gkotsis ◽  
Dimitra Banti ◽  
Anastasia Pritsa ◽  
Manassis Mitrakas ◽  
Petros Samaras ◽  
...  
Keyword(s):  
Dissolved Oxygen ◽  
Activated Sludge ◽  
Membrane Fouling ◽  
Municipal Wastewater ◽  
Pilot Scale ◽  
Operating Conditions ◽  
Mixed Liquor ◽  
Filamentous Microorganisms ◽  
Recirculation Rate ◽  
Improved Performance

This is the first study that examines the effect of operating conditions on fouling of Membrane Bio-Reactors (MBRs), which treat municipal wastewater in field conditions, with specific regard to the controlled development of filamentous microorganisms (or filaments). The novelty of the present work is extended to minimize the dissolved oxygen (DO) in recirculated activated sludge for improving the process of denitrification. For this purpose, two pilot-scale MBRs were constructed and operated in parallel: i) Filament-MBR, where an attempt was made to regulate the growth of filaments by adjustment of DO, the Food-to-Microorganisms (F/M) ratio and temperature, and ii) Control-MBR, where a gentle stirring tank was employed for the purpose of zeroing the DO in the recycled sludge. Results showed that low temperature (< 15 °C) slightly increased the number of filaments in the Filament-MBR which, in turn, decreased the Trans-Membrane Pressure (TMP). As the Soluble Microbial Products (SMP) and the colloids are considered to be the basic foulants of membranes in MBR systems, specific attention was directed to keep their concentration at low values in the mixed liquor. The low F/M ratio in the aeration tanks which preceded the membrane tank was achieved to keep the SMP proteins and carbohydrates at very low values in the mixed liquor, i.e., less than 6 mg/L. Moreover, as a result of the low recirculation rate (2.6∙Qin), good aggregation of the produced excess sludge was achieved, and low concentration of colloids with a size ≤50 nm (nearly the membranes’ pore size used for filtration/separation) was measured, accounted for maximum 15% of the total colloids. Additionally, the increase in filamentous population at the Filament-MBR contributed to the further reduction of colloids in the mixed liquor at 7.9%, contributing beneficially to the reduction of TMP and of membrane fouling. The diminishing of DO in the recirculated sludge improved denitrification, and resulted in lower concentrations of Ν-NO3− and TN in the effluent of the Control-MBR. Furthermore, the recirculation rate of Qr = 2.6∙Qin, in comparison with Qr = 4.3∙Qin, resulted in improved performance regarding the removal of N-NH4+. Finally, high organics removal and ammonium nitrification was observed in the effluent of both pilots, since COD and Ν-ΝΗ4+ concentrations were generally in the range of 10–25 mg/L and < 0.1 mg/L, respectively.

scholarly journals Dynamic characterization of a FeCl3-dosed anaerobic membrane bioreactor (AnMBR) treating municipal wastewater

2018 ◽  
Vol 2017 (2) ◽  
pp. 481-491 ◽  
Author(s):  
Qirong Dong ◽  
Wayne Parker ◽  
Martha Dagnew
Keyword(s):  
Membrane Bioreactor ◽  
Suspended Solids ◽  
Municipal Wastewater ◽  
Pilot Scale ◽  
Delayed Response ◽  
Transient Model ◽  
Mixed Liquor ◽  
Anaerobic Membrane Bioreactor ◽  
Membrane Performance ◽  
The Impact

Abstract A transient study was conducted at pilot scale to assess the impact of Fe dosage on the dynamics of biological and membrane performance of an anaerobic membrane bioreactor (AnMBR) treating authentic municipal wastewater. A transient model of the AnMBR system was employed to assist with interpretation of the observed responses in the mixed liquor under different FeCl3 dosages. A high dosage (43 mg FeCl3/LSewage) resulted in a significant accumulation of fixed suspended solids and volatile suspended solids (VSS) and reduction of colloidal COD in the mixed liquor. The elevated dosages appeared to reduce the biodegradability of VSS that was present in the raw wastewater. Intermediate dosages of FeCl3 (21–12 mg/L) had less effect on these responses and did not appear to affect VSS biodegradation. Membrane performance was significantly affected by FeCl3 dosage as indicated by reversible resistance (RR) and physically irreversible resistance (IR). RR was closely related to the colloidal COD in the mixed liquor, thus responded quickly to Fe dosage. Physically, IR had a delayed response to changes in the colloidal COD concentrations in the mixed liquor and this was attributed to the effect of slow mass transfer of colloidal matter between the mixed liquor and the membrane.

Improvement in aerobic sludge digestion through pH control: initial assessment of pilot-scale studies

1987 ◽  
Vol 14 (4) ◽  
pp. 477-484 ◽  
Author(s):  
B. C. Anderson ◽  
D. S. Mavinic
Keyword(s):  
Sodium Bicarbonate ◽  
Hydrated Lime ◽  
Ph Control ◽  
Pilot Scale ◽  
High Rate ◽  
Initial Assessment ◽  
Mixed Liquor ◽  
Solids Retention ◽  
Digestion Efficiency ◽  
The Individual

Waste-activated sludges from an extended-aeration, pilot-scale wastewater treatment facility and a high-rate, full-scale system were aerobically digested in 150 L pilot-scale digesters, operated in a semicontinuous (daily fill-and-draw) mode, at a standard 15-day solids retention time (SRT). To offset the mixed-liquor pH (MLpH) decrease normally encountered in these digesters (as a result of nitrification), hydrated lime and sodium bicarbonate were used in separate experiments to control MLpH in the series pH 6, 7, 8, and 9. Digester performance in the first stage of this work was assessed solely on the basis of reduction in total volatile suspended solids.The extended-aeration type sludge exhibited the greatest improvement in process performance under all pH-controlled conditions. Improvements in digestion efficiency of up to 80% over the uncontrolled reactors were noted. The use of lime resulted in greater digestion enhancement than did sodium bicarbonate with this sludge, without a significant increase in sludge solids production (owing to the low chemical doses required). Digestion efficiency of the high-rate type sludge was little improved (on a relative basis) with either chemical; however, absolute efficiencies in the individual digesters were, in some cases, nearly double those of the comparative extended-aeration sludge digesters. This difference appears to be a function of the process from which the digesting sludge originated, and seems to be influenced by the amount of easily oxidizable, endogenous substrate contained in the biomass. It was concluded that the extended-aeration type sludge was most amenable to enhanced digestion through pH control; as well, cost and process considerations made lime the chemical of choice. Key words: activated sludge, aerobic digestion, hydrated lime, mixed-liquor pH control, nitrification, process enhancement, pilot-scale, sodium bicarbonate.

Application of a Pilot-Scale Pulsed Electrocoagulation system to OCC-Based Paper Mill Effluent

TAPPI Journal ◽  
2009 ◽  
Vol 8 (3) ◽  
pp. 14-20 ◽  
Author(s):  
YUAN-SHING PERNG ◽  
EUGENE I-CHEN WANG ◽  
SHIH-TSUNG YU ◽  
AN-YI CHANG
Keyword(s):  
Water Quality ◽  
Quality Indicators ◽  
Paper Mill ◽  
Pilot Scale ◽  
Operating Conditions ◽  
Optimal Dosage ◽  
Water Quality Indicators ◽  
Paper Mill Effluent ◽  
Treated Effluent ◽  
True Color

Trends toward closure of white water recirculation loops in papermaking often lead to a need for system modifications. We conducted a pilot-scale study using pulsed electrocoagulation technology to treat the effluent of an old corrugated containerboard (OCC)-based paper mill in order to evaluate its treatment performance. The operating variables were a current density of 0–240 A/m2, a hydraulic retention time (HRT) of 8–16 min, and a coagulant (anionic polyacrylamide) dosage of 0–22 mg/L. Water quality indicators investigated were electrical con-ductivity, suspended solids (SS), chemical oxygen demand (COD), and true color. The results were encouraging. Under the operating conditions without coagulant addition, the highest removals for conductivity, SS, COD, and true color were 39.8%, 85.7%, 70.5%, and 97.1%, respectively (with an HRT of 16 min). The use of a coagulant enhanced the removal of both conductivity and COD. With an optimal dosage of 20 mg/L and a shortened HRT of 10 min, the highest removal achieved for the four water quality indicators were 37.7%, 88.7%, 74.2%, and 91.7%, respectively. The water qualities thus attained should be adequate to allow reuse of a substantial portion of the treated effluent as process water makeup in papermaking.

A pilot web former designed to study retention-formation relationships

2010 ◽  
Vol 25 (2) ◽  
pp. 185-194
Author(s):  
Anna Svedberg ◽  
Tom Lindström
Keyword(s):  
Pilot Scale ◽  
Operating Conditions ◽  
Montmorillonite Clay ◽  
Speed Ratio ◽  
Good Reproducibility ◽  
Total Solids ◽  
Retention Aids ◽  
Solids Content ◽  
Relationship Of ◽  
The Relationship

Abstract A pilot-scale fourdrinier former has been developed for the purpose of investigating the relationship between retention and paper formation (features, retention aids, dosage points, etc.). The main objective of this publication was to present the R-F (Retention and formation)-machine and demonstrate some of its fields of applications. For a fine paper stock (90% hardwood and 10% softwood) with addition of 25% filler (based on total solids content), the relationship between retention and formation was investigated for a microparticulate retention aid (cationic polyacrylamide together with anionic montmorillonite clay). The retention-formation relationship of the retention aid system was investigated after choosing standardized machine operating conditions (e.g. the jet-to-wire speed ratio). As expected, the formation was impaired when the retention was increased. Since good reproducibility was attained, the R-F (Retention and formation)-machine was found to be a useful tool for studying the relationship between retention and paper formation.

Nanofiltration of colored surface water: Quebec's experience

2003 ◽  
Vol 3 (5-6) ◽  
pp. 15-22
Author(s):  
P. Kouadio ◽  
M. Tétrault
Keyword(s):  
Drinking Water ◽  
Surface Water ◽  
Membrane Fouling ◽  
Pilot Scale ◽  
Operating Conditions ◽  
Quebec City ◽  
Water Regulation ◽  
Eastern Canada

Three colored surface water nanofiltration pilot-scale projects were conducted in the province of Quebec (eastern Canada), between November 2000 and March 2002, by the company H2O Innovation (2000) inc., for the municipalities of Lac Bouchette, Latulipe-et-Gaboury and Charlesbourg (now part of Quebec City). Results indicated that nanofiltration permeate quality has an advance on present drinking water regulation standard in Quebec, but important membrane fouling occurred. Fouling can be controlled by pretreatment and optimization of the operating conditions.

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