Effects of high sodium chloride concentrations on activated sludge treatment

1995 ◽  
Vol 31 (9) ◽  
pp. 61-72 ◽  
Author(s):  
M. F. Hamoda ◽  
I. M. S. Al-Attar
Keyword(s):  
Activated Sludge ◽  
Biomass Concentration ◽  
Experimental Conditions ◽  
High Sodium ◽  
Effluent Quality ◽  
Toc Removal ◽  
Activated Sludge System ◽  
Biological Solids ◽  
Solids Retention

The performance and kinetics of the activated sludge process treating wastewaters of freshwater and salinewater (10 g/l NaCl and 30 g/l NaCl) origin were investigated using bench-scale, completely mixed reactors operated at different biological solids retention times (BSRT's) in the range of 3 to 20 d and organic loadings in the range of 0.5 to 2.0 kg COD/kg VSS.d. It has been found that the organic (COD or TOC) removal efficiency and the effluent quality of the activated sludge system were not deteriorated as a result of constant application of NaCl to acclimated biomass. However, the salinity of the effluent increased. The salt did not inhibit biomass growth under the experimental conditions studied but rather increased the biomass concentration in the reactors due to selection of salt tolerant microbial species. It has been demonstrated that kinetic models developed for the freshwater activated sludge system can be used successfully for the salinewater system. Biokinetic coefficients were determined which can be used for process design.

scholarly journals Fate of selected pharmaceutically active compounds in the integrated fixed film activated sludge process

2017 ◽  
Vol 75 (11) ◽  
pp. 2680-2691 ◽  
Author(s):  
K. J. Murray ◽  
W. J. Parker ◽  
L. M. Bragg ◽  
M. R. Servos
Keyword(s):  
Activated Sludge ◽  
Municipal Wastewater ◽  
Nitrification Rate ◽  
Process Conditions ◽  
Batch Reactors ◽  
Experimental Conditions ◽  
Conventional Activated Sludge ◽  
Fixed Film ◽  
Solids Retention ◽  
Biomass Activity

The potential for integrated fixed film activated sludge (IFAS) processes to achieve enhanced transformation of pharmaceuticals relative to conventional activated sludge (CAS) processes was assessed. Previous studies have focused on direct comparisons of parallel reactors with and without fixed film carriers and little information is available on the impacts of how varying operating parameters impact the differences in observed pharmaceutical compound (PC) transformation capabilities between CAS reactors and those equipped with both an activated sludge (AS) and fixed film carriers. The testing was carried out using bench scale sequencing batch reactors fed with authentic municipal wastewater and operated at selected combinations of temperature and solids retention time (SRT). PC transformation efficiencies were assessed in a 22 factorial design that employed the IFAS and CAS processes, operated in parallel under identical process conditions. Nitrification rate testing that was conducted to obtain insight into the biomass activity demonstrated that IFAS consistently had improved nitrification kinetics despite lower mixed liquor volatile suspended solids levels thereby demonstrating the contribution of the biofilm to nitrification. Increased transformation of atenolol (ATEN; ranging from 10–60%) and trimethoprim (TRIM; ranging from 30–50%) in the IFAS equipped reactors relative to their respective activated sludge (AS) controls was observed under all experimental conditions. Negligible transformation of carbamazepine was observed in both reactors under all conditions investigated. More than 99% of acetaminophen was transformed in both configurations under all conditions. There was no correspondence between nitrification activity and TRIM removal in the control AS while conditions that stimulated nitrification in the control AS also resulted in enhanced removal of ATEN. The results of this study indicate that the integration of biofilms in AS processes enhances transformation of some PCs.

Estimation of Biomass Concentration and Population Dynamics in a Captor® Activated Sludge System

1994 ◽  
Vol 29 (7) ◽  
pp. 149-152 ◽  
Author(s):  
M. P. Reddy ◽  
K. R. Pagilla ◽  
P. R. Senthilnathan ◽  
H. W. Johnson ◽  
P. S. Golla
Keyword(s):  
Population Dynamics ◽  
Activated Sludge ◽  
Microbial Population ◽  
Biomass Concentration ◽  
Activated Sludge Process ◽  
Free Swimming ◽  
Activated Sludge System ◽  
Suspended Growth ◽  
Fixed Film ◽  
The Media

A technique was developed to measure the equivalent MLSS in the fixed film Captor® media-activated sludge process. The technique accounts for the wear in the media as well as unequal wear in different media. The microbial population variations encountered during three years of full scale operation of the Captor® process, at the Moundsville WWTP were recorded. It has been found that fixed film media seem to support predominantly rotifers, followed by free swimming ciliates, and single stalk ciliates. In contrast, the suspended growth activated sludge population contained lower level organisms, mostly free swimming ciliates, followed by stalk ciliates, flagellates, and a few rotifers.

Denitrification of nitrate-contaminated groundwater using a simple immobilized activated sludge bioreactor

2012 ◽  
Vol 66 (3) ◽  
pp. 517-524 ◽  
Author(s):  
Zhengfang Ye ◽  
Feng Wang ◽  
Haitao Bi ◽  
Zhongyou Wang ◽  
Guo-hua Liu
Keyword(s):  
Activated Sludge ◽  
Oxygen Demand ◽  
Operating Conditions ◽  
Nitrite Accumulation ◽  
Activated Sludge System ◽  
N Concentration ◽  
Immobilized Microorganisms ◽  
N Loading ◽  
Anaerobic Biomass

A simple anaerobic-activated sludge system, in which microorganisms are immobilized by a novel functional carrier, was used for removing nitrate in groundwater. The operating conditions, including hydraulic retention time (HRT), C/N ratio, temperature and NO3−-N loading concentration were investigated. The NO3−-N concentration, residual chemical oxygen demand (COD) and nitrite accumulation were used as indicators to assess the water quality of the effluent. The anaerobic biomass loading capacity in the carrier was 12.8 g/L and the denitrifying Pseudomonas sp. and Rhodocyclaceae bacterium were dominant among the immobilized microorganisms in the anaerobic-activated sludge. Under operating conditions of HRT= 1.5 h, C/N= 2–3 and T= 16.8–20 °C, the removal efficiency of NO3−-N exceeded 93%, corresponding to a relatively high denitrification rate of 0.73 kg NO3−-N m−3 d−1, when the NO3−-N loading concentration was 50 mg/L. The NO3−-N concentration of the effluent always met regulatory criteria for drinking water (<10 mg/L) in the main developed and developing countries. The effluent COD was also below 10 mg/L. Although some nitrite accumulated (0–1.77 mg/L) during the operating period, it can be decreased through adjusting the operating pH and HRT. The immobilized activated sludge system may be useful for the removal of nitrate from groundwater.

scholarly journals FENTON OXIDATION AS A STRATEGY TO PRESERVE THE BIOMASS IN THE ACTIVATED SLUDGE SYSTEM

2020 ◽  
Vol 50 (2) ◽  
pp. 145-150
Author(s):  
Lucila Inés Doumic ◽  
Maria Esperanza Almeida ◽  
Giuliana Giulietti ◽  
Maria A. Ayude ◽  
Ana Micaela Ferro Orozco
Keyword(s):  
Activated Sludge ◽  
Respiratory Activity ◽  
Negative Impact ◽  
Biomass Concentration ◽  
Fenton Oxidation ◽  
Fenton Process ◽  
Active Biomass ◽  
Activated Sludge System ◽  
Feasible Alternative ◽  
Pre Treatment

Wastewaters containing biocides constitute an increasing environmental pollution concern. In this work, the feasibility of implementing a pre-treatment based on the Fenton process to minimize the negative impact of biocide compounds, such as benzalkonium chlorides (BAC), on the activated sludge system was studied. The behavior of the microbial community in the presence of a BAC solution untreated (BAC100) or pre-treated by homogeneous Fenton oxidation (BAC100/HF) was analyzed. The addition of BAC100 to the activated sludge system caused a deleterious effect. The cellular lysis process caused a 30% decrease in biomass concentration. The inhibition of respiratory activity was 73%. In contrast, BAC100/HF caused no significant decrease in the biomass concentration or detectable inhibition of the respiratory activity. Besides, the consumption of easily oxidizable products was observed. Results indicated that the homogeneous Fenton process as a pre-treatment of wastewaters containing BAC could become a feasible alternative to protect active biomass in biological treatment systems.

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.

Operating Experiences at Low Solids Retention Time

1984 ◽  
Vol 16 (12) ◽  
pp. 661-672 ◽  
Author(s):  
T E Wilson ◽  
W A Ambrose ◽  
H O Buhr
Keyword(s):  
Activated Sludge ◽  
Retention Time ◽  
Suspended Solids ◽  
Volume Index ◽  
Sludge Volume Index ◽  
Effluent Quality ◽  
Mixed Liquor ◽  
Solids Retention Time ◽  
Solids Retention ◽  
Typically Achieving

Five full scale activated sludge plants have been operated at low solids retention time (SRT, monthly averages as low as 0.8 days) and mixed liquor suspended solids (MLSS, monthly averages as low as 500 mg/l) values for 2 to 3 years. Operating results for this period are compared to 3 to 3-1/2 years of operation at conventional, higher, SRT and MLSS values. The data show that the lower SRT operation provided better effluent quality, typically achieving less than 15 mg/l of BOD5 or suspended solids, while not significantly increasing either the total (dry) sludge production or the sludge volume index (SVI). These data indicate that plants can be built and operated using significantly smaller tankage than conventionally accepted.

Sign in / Sign up

Export Citation Format

Share Document