Long-term performance of side-stream deammonification in a continuous flow granular-activated sludge process for nitrogen removal from high ammonium wastewater

2015 ◽  
Vol 71 (8) ◽  
pp. 1241-1248 ◽  
Author(s):  
Babak Rezania ◽  
Donald S. Mavinic ◽  
Harlan G. Kelly
Keyword(s):  
Activated Sludge ◽  
Retention Time ◽  
Biomass Concentration ◽  
Granular Sludge ◽  
Operating Conditions ◽  
Activated Sludge Process ◽  
Conventional Activated Sludge ◽  
Wide Range ◽  
Nitrite Oxidizing Bacteria ◽  
Solids Retention

An innovative granular sludge deammonification system was incorporated into a conventional-activated sludge process. The process incorporated an internal baffle in the bioreactor for continuous separation of granular biomass from flocculent biomass, which allowed for controlling the solids retention time of flocculent sludge. The process was evaluated for ammonium removal from municipal digested sludge dewatering centrate under various operating conditions lasting over 450 days. The process successfully removed, on average, 90% of the ammonium from centrate at various ammonium loading reaching 1.4 kg/m3d at 20 hours hydraulic retention time. Controlling the retention time of the flocculent biomass and maintaining low nitrite concentration were both found to be effective for nitrite oxidizing bacteria management, resulting in a low nitrate concentration (below 50 mg/L) over a wide range of flocculent biomass concentration in the bioreactor.

PACTTM process for treatment of kraft mill effluent

1997 ◽  
Vol 35 (2-3) ◽  
pp. 283-290 ◽  
Author(s):  
R. M. Narbaitz ◽  
R. L. Droste ◽  
L. Fernandes ◽  
K. J. Kennedy ◽  
D. Ball
Keyword(s):  
Activated Sludge ◽  
Oxygen Demand ◽  
Pulp Mill ◽  
Operating Conditions ◽  
Activated Sludge Process ◽  
Conventional Activated Sludge ◽  
Adsorbable Organic Halides ◽  
Organic Halides ◽  
Solids Retention ◽  
Year 2000

The PACTTM process (powdered activated carbon addition to the activated sludge process) was evaluated for the treatment of Kraft pulp mill wastewater in a series of bench scale experiments. Possibly due to the relatively low strength wastewater, the PACTTM process with carbon doses between 0.5 and 1.0 g/L of influent only performed marginally better than the conventional activated sludge process. Chemical oxygen demand and toxicity, evaluated with the Microtox® assay, were among the parameters monitored. For the operating conditions tested the solids retention time had no impact on performance. The main improvement was increased in adsorbable organic halides (AOX) removal, the magnitude of the improvement was dependent on the wastewater batch and the carbon dose. However conventional activated sludge treatment will meet Ontario's year 2000 AOX regulations. An empirical model from the literature described the data fairly well.

Influences of wastewater composition and operating conditions on activated sludge bulking and scum formation

1994 ◽  
Vol 30 (11) ◽  
pp. 181-189 ◽  
Author(s):  
Jürg Kappeler ◽  
Willi Gujer
Keyword(s):  
Activated Sludge ◽  
Retention Time ◽  
Mass Fraction ◽  
Oxygen Supply ◽  
Reactor Design ◽  
Operating Conditions ◽  
Reactor Configuration ◽  
Growth Requirements ◽  
Filamentous Microorganisms ◽  
Solids Retention

Bulking and scum formation (scumming) are common phenomena in activated sludge plants. Four main problem groups with filamentous microorganisms with different growth requirements are distinguished: (1) “Aerobic Bulking”, (2) “Scumming due to Actinomycetes”, (3) “Low F/M Bulking and Scumming” and (4) “Bulking due to Sulphide Oxidising Bacteria”. Various wastewater fractions, such as readily biodegradable substrate, surfactants, hydrophilic and lipophilic slowly-biodegradable substrate, inoculated filamentous microorganisms and sulphide, strongly influence the biocenosis composition. Apart from wastewater composition, operating conditions, such as solids retention time, reactor configuration, mechanical stress by recirculation pumps and insufficient oxygen supply, are often decisive for the occurrence of a bulking or scumming problem, as well. A predictive scheme for the possible occurrence of the four main problem groups is presented for different combinations of wastewater compositions, operating conditions and reactor design. All four problem groups can occur in aerobic nitrifying systems. In non-nitrifying systems, only “Aerobic Bulking” and “Bulking due to Sulphide Oxidising Bacteria” are expected, depending on wastewater composition and operating conditions. In systems with a large anoxic mass fraction, “Low F/M Bulking and Scumming” is typically the only problem group. Since wastewater fractions can hardly be manipulated in practice, at least operating conditions and reactor design should be optimised in order to obtain a better performance of the plants.

An innovative approach to reduce excess sludge production in the activated sludge process

1994 ◽  
Vol 30 (9) ◽  
pp. 11-20 ◽  
Author(s):  
H. Yasui ◽  
M. Shibata
Keyword(s):  
Activated Sludge ◽  
Biomass Concentration ◽  
Experimental Period ◽  
Aeration Tank ◽  
Activated Sludge Process ◽  
Biological Degradation ◽  
Excess Sludge ◽  
Conventional Activated Sludge ◽  
New Process ◽  
Sludge Production

A new process has been developed to reduce excess sludge production, in which both excess sludge digestion and wastewater treatment are conducted simultaneously in the same aeration tank. The ozonation enhances biological degradation of the activated sludge, which is decomposed in a subsequent biological treatment. A considerable amount of biomass is mineralized biologically in proportion to the amount of recirculated biomass from the ozonation stage to the biological stage. It was observed that the amount of excess sludge is reduced to nearly zero when 1.2 kg/m3-aeration tank volume of biomass is recirculated in a day from the biological stage to the ozonation stage at a BOD loading of 1.0 kg/m3/d. A biomass concentration of 4200 mg/L was maintained at 1.0 kg-BOD/m3/d without drawing excess sludge for 6 weeks of experimental period under ozone dose of 0.05 g-O3/g-SS and recirculation rate at 0.3 d−1. Only a limited difference in the effluent quality was observed between the new process and the conventional activated sludge process.

Production of Sludge in a Submerged Membrane Bioreactor and Dewatering Aspects

2007 ◽  
Vol 5 (1) ◽  
Author(s):  
Watsa Khongnakorn ◽  
Christelle Wisniewski
Keyword(s):  
Activated Sludge ◽  
Water Reuse ◽  
Membrane Bioreactor ◽  
Operating Conditions ◽  
Good Prediction ◽  
Activated Sludge Process ◽  
Conventional Activated Sludge ◽  
Sludge Dewaterability ◽  
Conventional Activated Sludge Process ◽  
Sludge Production

In wastewater treatment, the membrane bioreactor (MBR) holds the potential to become one of the new generation processes, ensuring effluent quality and disinfection of sufficiently high levels to allow water reuse and recycle. Furthermore, the possibility to operate with high biomass concentrations (2 to 5 times higher than in conventional activated sludge process, CAS) allows to impose high solid retention times(SRT) that can be beneficial to a sludge production reduction and so to a reduction of disposal costs. These non-conventional operating conditions (high SRT) can also induce different sludge characteristics and dewatering aptitude, which are essential parameters for the optimization of the sludge post-treatment, like mechanical dewatering. The objective of this work was to study the performances of a complete sludge retention membrane bioreactor, in terms of organic removal efficiency, sludge production and sludge dewaterability. The adaptability of Activated Sludge Model 3 (ASM3) to provide good prediction results of high SRT-MBR was studied. Typical parameters adopted to describe sludge dewaterability were quantified and compared with the conventional activated sludge process (CAS).

Comparison of Yields and Decay Rates for a Biological Nutrient Removal Process and a Conventional Activated Sludge Process

1992 ◽  
Vol 26 (9-11) ◽  
pp. 2195-2198 ◽  
Author(s):  
S. A. McClintock ◽  
V. M. Pattarkine ◽  
C. W. Randall
Keyword(s):  
Activated Sludge ◽  
Nutrient Removal ◽  
Pilot Scale ◽  
Decay Rates ◽  
Growth Yields ◽  
Biological Nutrient Removal ◽  
Activated Sludge Process ◽  
Conventional Activated Sludge ◽  
Aerobic Process ◽  
Solids Retention

Two pilot-scale activated sludge reactors, one VIP (named after Virginia Initiative Plant) biological nutrient removal (BNR) process and one conventional, fully aerobic process, were operated over a range of solids retention times (SRT's) and under the same conditions so that growth yields and specific decay rates could be evaluated and compared. True growth yields (Y's) for the BNR and the conventional processes were equal and were 0.41 gVSS/gCOD. The specific decay rate, b, for the BNR process, 0.063 d, was lower than in the fully aerobic process, 0.110 d-1, indicating that decay occurs at a much lower rate in the anoxic and anaerobic zones of the BNR process.

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