Technological characteristics of reject waters from aerobic sludge stabilization in small and medium-sized wastewater treatment plants with biological nutrient removal

Biological Nutrient Removal ◽

Sludge Stabilization ◽

Aerobic Stabilization ◽

Multi Phase ◽

The Impact ◽

Aerobic Sludge

Abstract Most studies on the impact of reject waters recycled from sludge processing in the multi-phase activated sludge process focus on anaerobic sludge treatment in large wastewater treatment plants, leaving apart the processes of aerobic sludge stabilization often used in smaller facilities in rural and suburban areas. The article presents the results of tests carried out in three small and medium-sized wastewater treatment plants with biological removal of biogenic compounds that use aerobic stabilization to process sludge. The research concerned the quantity and quality of reject waters generated in the process of aerobic stabilization and dewatering of sewage sludge and their impact on the multi-phase activated sludge process. The results showed that the average volume of generated reject waters ranged from 3.2 to 5% of the incoming wastewater volume. The average share of organic compounds and total nitrogen loads contained in reject waters did not usually exceed 5–10% of the loads in raw wastewater but reached almost 50% in the case of total phosphorus. Studies indicated that the composition of the supernatant from aerobic stabilization is strongly dependent on the course of the process. The best quality was obtained for cyclic operation of the aerobic stabilization tank with 16 h of aeration and 8 h of settling. The results also showed the negative impact of sudden discharges of reject waters from sludge processing to a multi-phase biological reactor, which can be reduced by using an appropriate equalization tank and pretreatment of the side stream to reduce the recirculation of phosphorus.

Biosensor-based control of nitrification inhibitor in municipal wastewater treatment plants

10.2166/wst.2006.141 ◽

2006 ◽

Vol 53 (4-5) ◽

pp. 357-366 ◽

Cited By ~ 1

Author(s):

Y. Okayasu ◽

H. Tanaka ◽

T. Inui ◽

Y. Tanaka

Keyword(s):

Wastewater Treatment ◽

Activated Sludge ◽

Municipal Wastewater ◽

Nitrification Inhibitor ◽

Nitrifying Bacteria ◽

Municipal Wastewater Treatment ◽

Municipal Wastewater Treatment Plants ◽

The Impact

The effect of potassium cyanide (KCN) on nitrification processes in municipal wastewater treatment plants was studied by batch nitrification tests, which indicated that nitrification processes tend to be inhibited at a lower KCN concentration than the present discharge standard to sewerage. The experiment of the biosensor using nitrifying bacteria was also conducted for continuous monitoring of nitrification inhibitor in influent wastewater, and demonstrated that the biosensor can detect KCN at as low as EC10 of the abovementioned batch nitrification test. Moreover, to determine the effectiveness of application of the biosensor to avoid the impact of KCN due to an accidental spillage in a sewerage system, KCN was intentionally injected into the experimental models of activated sludge process equipped both with and without the biosensor. The model with the biosensor that could detect KCN could divert the wastewater including KCN to a refuge tank, which resulted in the avoidance of upset of the activated sludge process. On the other hand, the model without the biosensor was upset in the nitrification process due to KCN. Such differences demonstrate the effectiveness of the biosensor applied to countermeasures of an accidental spillage of toxic chemicals to avoid upset of nitrification in municipal wastewater treatment plants.

Controlling Activated Sludge Process Using EFOR

10.2166/wst.1992.0459 ◽

1992 ◽

Vol 26 (3-4) ◽

pp. 783-790

Author(s):

J. Pedersen

Keyword(s):

Wastewater Treatment ◽

Activated Sludge ◽

Treatment Plant ◽

Simulation Program ◽

Activated Sludge Model

A newly developed simulation program, based on the Activated Sludge Model No. 1, has been investigated for its controlling abilities. The program is capable of simulating most of the control types which have been applied to wastewater treatment plants. The program was tested on a nitrifying and a denitrifying treatment plant. The results showed that the model makes good simulations of the applied controls.

Removal Characteristics of Human Antibiotics during Wastewater Treatment in Japan

Water Practice & Technology ◽

10.2166/wpt.2006.059 ◽

2006 ◽

Vol 1 (3) ◽

Cited By ~ 9

Author(s):

Y. Kobayashi ◽

M. Yasojima ◽

K. Komori ◽

Y. Suzuki ◽

H. Tanaka

Keyword(s):

Wastewater Treatment ◽

Activated Sludge ◽

Treatment Plant ◽

Treatment Method ◽

Batch Experiment ◽

Aqueous Environment ◽

Conventional Activated Sludge Process

Conventional Activated Sludge ◽

Pharmaceuticals resident in sewage and in the aqueous environment has begun to attract attention. The objectives of this research were to clarify the behaviour of selected human antibiotics in wastewater treatment plants, namely levofloxacin (LVFX), clarithromycin (CAM) and azithromycin (AZM) which are much used in Japan. The concentrations in raw influent of LVFX, CAM, AZM were respectively 425~981ng/L, 340~573ng/L, ND(<190 ng/L)~371ng/L. The averages of removal ratio were about 50 % for all selected antibiotics. It was suggested that selected antibiotics was not too much removed in the conventional creature processing like the conventional activated sludge process. The remarkable removals in activated sludge tank using high class treatment method were confirmed about all selected antibiotics. The rise of the concentrations of CAM and AZM was confirmed after the addition of chemical coagulants in one wastewater treatment plant. From the result of batch experiment with activated sludge, it was suggested that LVFX and AZM were removed from water mainly by the absorption to activated sludge. Also, in batch experiment with chemical coagulants, it was suggested that LVFX was removed from water and CAM, AZM were eluted a little in water by adding sulphuric acid band.

The limits and ultimate possibilities of technology of the activated sludge process

10.2166/wst.2008.545 ◽

2008 ◽

Vol 58 (8) ◽

pp. 1671-1677 ◽

Cited By ~ 3

Author(s):

A. F. van Nieuwenhuijzen ◽

A. G. N. van Bentem ◽

A. Buunnen ◽

B. A. Reitsma ◽

C. A. Uijterlinde

Keyword(s):

Wastewater Treatment ◽

The Netherlands ◽

Activated Sludge ◽

Municipal Wastewater ◽

Treatment Method ◽

Municipal Wastewater Treatment ◽

Nitrogen And Phosphorus ◽

Activated Sludge Processes

The (low loaded) biological nutrient removing activated sludge process is the generally accepted and applied municipal wastewater treatment method in the Netherlands. The hydraulical and biological flexibility, robustness and cost efficiency of the process for advanced removal of nutrients like nitrogen and phosphorus without (too much) chemicals results in a wide application of the activated sludge process within Dutch waterboards. Presumably, wastewater treatment plants will have to contribute to the improvement of the quality of the receiving surface waters by producing cleaner effluent. In this perspective, the Dutch research organisation STOWA initiated a research project entitled “The Boundaries of the Activated Sludge Process” to investigate the possibilities and limitations of activated sludge processes to improve the effluent quality. It is concluded that the activated sludge process as applied and operated at WWTP's in the Netherlands has the potential to perform even better than the current effluent discharge standards (10 mg Ntotal/l and 1 mg Ptotal/l). Reaching the B-quality effluent (<5mg Ntotal/l and <0.3 mg Ptotal/l) will be possible at almost all WWTPs without major adjustments under the conditions that: the sludge load is below 0.06 kg BOD/kg TSS.d the internal recirculation is above 20 the BOD/N ratio of the influent is above 3. Complying with the A-quality effluent (<2.2 Ntotal/l and <0.15 mg Ptotal/l) seems to be difficult (but not impossible) and requires more attention and insight into the activated sludge process. Optimisation measures to reach the A-quality effluent are more thorough and are mostly only achievable by additional construction works (addition of activated sludge volume, increasing recirculation capacity, etc.). It is furthermore concluded that the static HSA-results are comparable to the dynamic ASM-results. So, for fast determinations of the limits of technology of different activated sludge processes static modelling seems to by sufficient.

Activated sludge wastewater treatment plants optimisation to face pollution overloads during grape harvest periods

10.2166/wst.2005.0010 ◽

2005 ◽

Vol 51 (1) ◽

pp. 81-88 ◽

Cited By ~ 20

Author(s):

C. Beck ◽

G. Prades ◽

A.-G. Sadowski

Keyword(s):

Wastewater Treatment ◽

Activated Sludge ◽

Management Strategies ◽

Treatment Plant ◽

Weather Conditions ◽

Organic Load ◽

Process Line ◽

The Impact ◽

Load Conditions

The principal objective of our study was to optimise a municipal activated sludge wastewater treatment plant (WWTP) to face high organic flows due to viticulture effluents inputs. Treatment file optimization consisted in testing different treatment lines, changing the number and volume of biological basins and clarifiers, with or without a buffer basin upstream, with a view to achieving a better reduction of COD. The actual WWTP biological stage is composed of two aerated basins whose total volume is 1365 m3. The studied cases are successively, the installation of a single basin of 1365 m3, then of several basins whose total volume remains constant and equal to 1365 m3. Another case was also considered, that of an aerated basin followed by a first clarifier and then, by another aerated basin and a second clarifier. All scenarios presented below were evaluated, for standard dry weather conditions and for high organic load conditions, as encountered during the grape harvest period. The method used was to carry out various simulations, using numerical modelling, and to compare the impact of different process line scenarios and management strategies on the activated sludge WWTP efficiencies.

R-D-N Activated Sludge Process

10.2166/wst.1992.0490 ◽

1992 ◽

Vol 25 (4-5) ◽

pp. 151-160 ◽

Cited By ~ 2

Author(s):

M. Kos ◽

J. Wanner ◽

I. Šorm ◽

P. Grau

Keyword(s):

Wastewater Treatment ◽

Activated Sludge ◽

Optimum Design ◽

Wastewater Treatment Plant ◽

Treatment Plant ◽

Design Parameters ◽

Reduced Volume ◽

Sludge Settling ◽

Aerobic Sludge

The modification of denitrification - nitrification activated sludge process with reaeration of concentrated returned sludge was tested in pilot units with municipal wastewaters at the Prague wastewater treatment plant. The ability of the R-D-N Process to increase the aerobic sludge age with a reduced volume demand was verified. The sludge settling properties were evaluated and the effect of recirculation, simultaneous denitrification and compartmentalization of the denitrification zone was studied. Optimum design parameters of the R-D-N process are suggested.

Occurrence of Cryptosporidium in Japan and counter-measures in wastewater treatment plants

10.2166/wst.2001.0734 ◽

2001 ◽

Vol 43 (12) ◽

pp. 183-186 ◽

Cited By ~ 9

Author(s):

M. Suwa ◽

Y. Suzuki

Keyword(s):

Wastewater Treatment ◽

Activated Sludge ◽

Treated Wastewater ◽

Counter Measures ◽

Low Levels

The outbreak of cryptosporidiosis in Ogose in 1996 forced the wastewater treatment authorities to rethink the level of contamination by Cryptosporidium of wastewater and waters in the watersheds and counter-measures in wastewater treatment plants. A survey of Cryptosporidium concentrations in wastewater and treated wastewater conducted nationwide showed relatively low levels. Also, evaluation of wastewater treatment showed a 2 log oocyst removal with an activated sludge process and an additional 1 log removal with coagulant dosing.

A REDUCED-ORDER ODE–PDE MODEL FOR THE ACTIVATED SLUDGE PROCESS IN WASTEWATER TREATMENT: CLASSIFICATION AND STABILITY OF STEADY STATES

Mathematical Models and Methods in Applied Sciences ◽

10.1142/s0218202512500509 ◽

2013 ◽

Vol 23 (03) ◽

pp. 369-405 ◽

Cited By ~ 5

Author(s):

STEFAN DIEHL ◽

SEBASTIAN FARÅS

Keyword(s):

Wastewater Treatment ◽

Activated Sludge ◽

Hyperbolic Conservation Laws ◽

Coupled System ◽

Steady States ◽

Hyperbolic Conservation ◽

Flux Function ◽

Sedimentation Tank

Most wastewater treatment plants contain an activated sludge process, which consists of a biological reactor and a sedimentation tank. The purpose is to reduce the incoming organic material and dissolved nutrients (the substrate). This is done in the biological reactor where micro-organisms (the biomass) decompose the substrate. The biomass is then separated from the water in the sedimentation tank under continuous in- and outflows. One of the outflows is recirculated to the reactor. The governing mathematical model describes the concentration of substrate and biomass as functions of time for the biological reactor, and as functions of time and depth for the sedimentation tank. This gives rise to a system of two ODEs for the reactor coupled with two spatially one-dimensional PDEs for the sedimentation tank. The main mathematical difficulty lies in the nonlinear PDE modeling the continuous sedimentation of the biomass. Previous analyses of models of the activated sludge process have included excessively simplifying assumptions on the sedimentation process. In this paper, results for nonlinear hyperbolic conservation laws with spatially discontinuous flux function are used to obtain a classification of the steady states for the coupled system. Their stability to disturbances are investigated and some phenomena are demonstrated by a numerical simulation.

Activated Sludge Respiration Activity Inhibition Caused by Mobile Toilet Chemicals

Processes ◽

10.3390/pr8050598 ◽

2020 ◽

Vol 8 (5) ◽

pp. 598 ◽

Cited By ~ 1

Author(s):

Tomáš Vítěz ◽

Monika Vítězová ◽

Markéta Nováčková ◽

Ivan Kushkevych

Keyword(s):

Wastewater Treatment ◽

Activated Sludge ◽

Wastewater Treatment Plant ◽

Respiratory Activity ◽

Treatment Plant ◽

Respiration Activity ◽

Wastewater Treatment Process ◽

The Impact ◽

Active Substances

Ensuring high quality drinking water sources is important task nowadays. To reach this task, knowledge about the impact of different chemicals on aerobic wastewater treatment is mandatory. A mixture of different chemicals reaches wastewater treatment plant every day. With the growing discharge volume of mobile toilet chemicals, active substances in these products in the past years have been recorded. The respiratory activity of activated sludge was determined to show how mobile toilet chemicals and their active substances may affect the biological wastewater treatment process. The results show negative effect of formaldehyde and bronopol on respiratory activity of activated sludge. The wastewater treatment plants influent composition and size also play important roles. Results shows that activated sludge microorganisms at a wastewater treatment plant in industrial urban area may be adapted to the higher pollutants concentration. When mobile toilet tanks are directly discharged at smaller wastewater treatment plant, an activated sludge process can be affected. For treating mobile toilet wastewater, bacterial degraders can be used. During our respiratory activity experiments, potential degraders were searched. Ralstonia sp. prevails in all samples and it is therefore a potential mobile toilet chemicals degrader.

Nutrient Removal Performance on Domestic Wastewater Treatment Plants (Full Scale System) between Tropical Humid and Cold Climates

Applied Environmental Research ◽

10.35762/aer.2018.40.2.3 ◽

2018 ◽

pp. 32-39

Author(s):

Pongsak Noophan ◽

Rawiwan Rodpho ◽

Pimook Sonmee ◽

Martha Hahn ◽

Suthep Sirivitayaphakorn

Keyword(s):

Wastewater Treatment ◽

Activated Sludge ◽

Nutrient Removal ◽

Domestic Wastewater ◽

Full Scale ◽

Biological Nutrient Removal ◽

Cold Climates ◽

Domestic Wastewater Treatment ◽

Warm Climates

Two full scale systems of oxidation ditches for domestic wastewater treatment plants (WWTP) were used as study sites: Phuket Province, southern Thailand (representative of tropical humid climates) and Plum Creek, Castle Rock, Colorado, USA (representative of cold climates). The treatment systems at both sites were designed for biological nutrient removal (BNR) fromextended activated sludge. Nitrogen is removed by nitrification-denitrification processes. The solid retention time (SRT) for both treatment plants was ≥ 10 das recommended by theory for complete nitrification in activated sludge wastewater treatment plants. Influents and effluents from these sites were compared in respect to flow rate, biochemical oxygen demand (BOD), organic nitrogen, ammonium, nitrate, total nitrogen, and phosphorus concentrations. At both sites, nutrient removal reached more than 75% because there was sufficient carbon for denitrifying and phosphate accumulating organisms. Furthermore, low dissolved oxygen concentration, long SRT, and hightemperature could be key factors to promote activity of some groups of bacteria in consuming organic matter and nutrients in wastewater in warm climates. For this reason, plant design and operating procedures for wastewater treatment in cold climates might not be always be applicable to warm climates.