Ciliated protozoa and organic load at low temperatures in an aerated biofilter

2002 ◽  
Vol 46 (1-2) ◽  
pp. 243-248 ◽  
Author(s):  
C. García-Santana ◽  
S. González-Martínez
Keyword(s):  
Experimental Work ◽  
Municipal Wastewater ◽  
Morphological Characteristics ◽  
Organic Load ◽  
Ciliated Protozoa ◽  
Organic Loading ◽  
Temperature Changes ◽  
Effluent Quality ◽  
Loading Rates ◽  
Wastewater Systems

Ciliated protozoa have been widely used as water quality indicators because their main morphological characteristics are relatively simple to identify microscopically. The species and individual numbers in wastewater treatment systems are a consequence of the operational and environmental conditions of the process. The main objective of this research was to relate the effluent quality of a pilot aerated biofilter with the presence and relative abundance of ciliated protozoa when operated under different organic loading rates. The experimental work was done in a pilot aerated biofilter using 12 mm volcanic porous stones as filtering media and it was fed with municipal wastewater adjusting the experiments to 3 organic loading rates (3, 7, and 9 gCOD/m2·d). Temperature in the filter varied from 11 to 14°C during the experimental work. COD and BOD removal rates do not change significantly with the different organic loads. Nitrification improves inversely to the organic load and it does not show dependence on the slight temperature changes observed. Eighteen species were identified as typical residents in wastewater systems. Free swimming species prefer higher organic loads. Crawling and attached species did not show significant changes with the organic load. According to the saprobity index of Pantle and Buck, the system, independently of the organic load, presented typical α-mesosaprobe level.

Biological aerated filtration of municipal wastewater using a low-cost filtration media

2007 ◽  
Vol 55 (7) ◽  
pp. 255-262 ◽  
Author(s):  
S. González-Martínez ◽  
T. Millán ◽  
O. González-Barceló
Keyword(s):  
Municipal Wastewater ◽  
Low Cost ◽  
Ammonia Removal ◽  
Organic Load ◽  
Organic Loading ◽  
Removal Rates ◽  
Loading Rates ◽  
Different Depths ◽  
The Mean ◽  
Kjeldahl Nitrogen

The main objective of this research was to demonstrate that selected natural lava stones can be successfully used for low-cost aerobic biofiltration of municipal wastewater. To demonstrate the procedure a pilot filter was built using 6 mm lava stones as support material. The filter depth was 3.0 m. Provided with sampling ports at different depths analysis of the wastewater could be made for COD, TSS, ammonia and nitrates nitrogen, pH, temperature and Kjeldahl nitrogen. Backwashing was performed every 72 hours. Total and dissolved COD and TSS behaved similarly with the organic load: The highest removal rates were observed with the lowest organic load of 0.8 kgCOD/m3 d. These removal rates decreased to a minimum value at organic loading rates of 1.5 kgCOD/m3 d and then remained without noticeable changes to the highest value of 3.5 kgCOD/m3 d. The highest total and dissolved COD removal values were 81 and 84%, respectively. For TSS the best removal value was 95%. Up to 75% ammonia removal was achieved at the lowest organic load of 0.8 kgCOD/m3 d. Ammonia removal decreased to 36% with a higher organic load of 1.6 kgCOD/m3 d. The Mean Cellular Retention (MCRT) time varied from 1 to 6 days with an average of 3.2 days. This fact proves that the MCRT depends on the backwashing frequency more than of any other factor involved. The bed volume decreased in about 5% after 300 days of operation. Microscopic observations showed that the small stones were rounder after 300 days and that the volume losses were caused when the edges of the stones were cut by the abrasion caused by backwashing.

A new low-cost biofilm carrier for the treatment of municipal wastewater in a moving bed reactor

2004 ◽  
Vol 48 (11-12) ◽  
pp. 243-250 ◽  
Author(s):  
J.C. Orantes ◽  
S. González-Martínez
Keyword(s):  
Municipal Wastewater ◽  
Low Cost ◽  
Cod Removal ◽  
Organic Load ◽  
Internal Diameter ◽  
Organic Loading ◽  
Efficient System ◽  
Moving Bed ◽  
Loading Rates ◽  
Biofilm Carrier

The Moving Bed Biofilm Reactor has proven to be an efficient system in wastewater treatment and has become a viable solution for small treatment plants. The main objective of this research was to analyse the performance of a moving bed reactor using low-cost local material when fed with municipal wastewater. A pilot reactor with a total volume of 900 litres was built and it was fed continuously with municipal wastewater. The operation of the system was adjusted to six different organic loading rates. The biofilm carrier was polyethylene tubing with internal diameter of 1.1 cm, cut into pieces of 1.2 cm. The tested material offered a specific surface area of 590 m2/m3. Air was provided with a fine-bubble diffuser. The main results show that the reactor performance was stable and predictable. The COD removal confidently behaves according to a general hyperbolic kinetic equation. The maximal total COD removal attained was 81%. Nitrification was observed only for organic loads with values under 5.7 gCOD/m2·d. Good adherence of the microorganisms was observed for the applied organic loading rates. After several months of operation, the material showed no signs of abrasion or deformation. The sludge production behaved linearly with the organic load reaching 979 gTSS/d with the highest organic load of 35.7 gCOD/m2·d. The amount of microorganisms attached to the carrier increased with the organic load tending to an asymptotical maximal value of 17.3 g/m2 (as dry solids). Mean cellular retention times from 2.0 to 23.1 days were determined.

Wastewater fermentation and nutrient removal in sequencing batch reactors

1998 ◽  
Vol 38 (1) ◽  
pp. 255-264 ◽  
Author(s):  
Germán Cuevas-Rodríguez ◽  
Óscar González-Barceló ◽  
Simón González-Martínez
Keyword(s):  
Activated Sludge ◽  
Volatile Fatty Acids ◽  
Organic Load ◽  
Batch Reactors ◽  
Sequencing Batch Reactors ◽  
Organic Loading ◽  
Nitrogen And Phosphorus ◽  
Loading Rates ◽  
Average Value ◽  
Experimental Runs

This research project was conducted to analyze the performance of a SBR reactor when being fed with anaerobically fermented wastewater. Important was to determine the capacity of the system to remove nitrogen and phosphorus. Two SBR reactors, each one with a volume of 980 liters, were used: one used as fermenter and the other as activated sludge SBR. Using 8-hour cycles, the reactors were operated and studied during 269 days. The fermenter produced an effluent with an average value of 223±24 mg/l of volatile fatty acids. The activated sludge SBR was tested under 3 organic loading rates of 0.13, 0.25, and 0.35 kgCODtotal/kgTSS·d. For the three tested organic loading rates, PO4-P concentrations under 1.1 mg/l and COD between 37 and 38 mg/l were consistently achieved. Exceptionally high NH4-N influent values were measured during the time of the experimentation with the organic load of 0.25 kgCODtotal/kgTSS·d, not reaching in this case full nitrification. Denitrification was observed during the fill phase in every cycle. SVI values between 40 and 70 were determined during the experimental runs.

Biological degradation of a mixture of municipal wastewater and organic garbage leachate in expanded bed anaerobic reactors and a zeolite filter

2009 ◽  
Vol 59 (4) ◽  
pp. 723-728 ◽  
Author(s):  
P. Castilla ◽  
L. Aguilar ◽  
M. Escamilla ◽  
B. Silva ◽  
Z. Milán ◽  
...  
Keyword(s):  
Suspended Solids ◽  
Municipal Wastewater ◽  
Total Suspended Solids ◽  
Granular Sludge ◽  
Biological Degradation ◽  
Organic Loading ◽  
Methanogenic Activity ◽  
Loading Rates ◽  
Anaerobic Reactors ◽  
Removal Efficiencies

Municipal wastewater was amended with organic garbage leachates at a concentration around 700 mgCODsoluble/L and fed to three different anaerobic systems to compare their performance: a down flow fluidized bed (DFFB), an expanded granular sludge bed (EGSB) and a zeolite-packed anaerobic filter reactor (ZPF). The DFFB and EGSB reactors were operated at HRT of 6 and 4 h and the ZPF reactor at 12 and 36 h. Organic loads rate for the DFFB reactor were 2.3±0.9 and 4.8±1.8 gCOD/L·d, with removal efficiencies around 40% and a methane productivity of 0.2±0.03 L/Lreactor·d. For the EGSB reactor, organic loads tested were 2.1±0.9 and 4.3±1.3 gCOD/L·d, removal efficiencies attained were of 77.6±12.7% and 84.4±4.9%, respectively at both conditions and total suspended solids were removed in 54.6±19.3%, while methane productivity at 4 h HRT was of 1.29±0.4 L/Lreactor·d. The ZPF reactor was operated at lower organic loading rates, 1.4±0.27 and 0.42±0.13 gCOD/L·d and attained removal efficiencies of 48±18% and 83±8%, respectively, reaching a methane productivity of 0.21±0.09 and 0.12±0.04 L/Lreactor·d, 83±8.0% of total suspended solids were retained in the reactor and as HRT was increased ammonium concentrations increased in 39%. Specific methanogenic activity in all systems was around 0.2 gCOD-CH4/gVSS d.

Treatment of agricultural drainage water via downflow hanging sponge system for reuse in agriculture

2013 ◽  
Vol 13 (2) ◽  
pp. 403-412 ◽  
Author(s):  
Amr Fleifle ◽  
Ahmed Tawfik ◽  
Oliver C. Saavedra ◽  
Mohamed Elzeir
Keyword(s):  
Suspended Solids ◽  
Oxygen Demand ◽  
Drainage Water ◽  
Treated Wastewater ◽  
Agricultural Drainage ◽  
Organic Loading ◽  
Effluent Quality ◽  
Loading Rates ◽  
Agricultural Drainage Water ◽  
Negative Effect

Treatment of agricultural drainage water (ADW) in a down-flow hanging sponge (DHS) reactor has been investigated for a period of 1 y. The reactor was operated at different hydraulic retention times (HRTs) of 5.26, 2.63, and 1.5 h and corresponding organic loading rates (OLRs) of 2.01, 1.86, and 4.43 kg COD/m3 d, respectively. The results obtained indicated that, decreasing the HRT from 5.26 to 1.5 h negatively affected the chemical oxygen demand (COD) removal. Average COD percentage removal values dropped from 89.3 ± 5.4 to 72.2 ± 16% respectively. Total suspended solids (TSS) concentrations were reduced by 85.5 ± 8.3, 90.4 ± 2.1, and 91.4 ± 4.9 at HRTs of 5.26, 2.63, and 1.5 h, respectively. However, the nitrification efficiency was slightly decreased from 85.2 ± 17.4 to 82 ± 11.4% by decreasing the HRT from 5.26 to 1.5 h and increasing the OLR from 2.01 to 4.43 kg COD/m3 d, respectively. Likewise, reducing the HRT from 5.26 to 1.5 h exerted a slight negative effect on the removal of the total phosphorus (TP). Based on these results it is recommended to operate such a system at a HRT of 2.63 h and OLR not exceeding 2.0 kg COD/m3 d for providing an effluent quality complying with the standards regulating the use of treated wastewater for agricultural purposes.

scholarly journals Characteristics and performance of small and medium wastewater treatment plants in Greece

2017 ◽  
Vol 12 (3) ◽  
pp. 520-533
Author(s):  
E. Gavalakis ◽  
P. Poulou ◽  
A. Tzimas
Keyword(s):  
Wastewater Treatment ◽  
Phosphorus Removal ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Waste Water Treatment ◽  
Organic Load ◽  
Wastewater Management ◽  
Effluent Quality ◽  
Future Challenges ◽  
And Performance

Wastewater management in Greece is being regulated by the Urban Waste Water Treatment Directive (UWWTD) and as a result many wastewater treatment plants (WWTPs) have been constructed during the last 30 years and are in operation. The present work aims to outline the progress regarding the implementation of the specific environmental policy, present deficiencies and future challenges, while an evaluation of the performance is conducted for small-medium and large WWTPs focusing on the influent and effluent quality characteristics. In Greece the existing level of treatment provided is related to secondary treatment for the removal of organic load, which in most cases is supplemented by nitrogen removal (for more than 85% of the WWTPs) and phosphorus removal. With respect to the characteristics of the raw municipal wastewater these correspond to typical low to medium strength sewage. Compliance to the UWWTD effluent standards for BOD5, COD and SS is achieved in more than 90% of the WWTPs, while in terms of nutrients, 80% of the WWTPs efficiently remove nitrogen and approximately 45% of the WWTPs remove phosphorus.

Combined treatment of leachate from sanitary landfill and municipal wastewater by UASB reactors

2009 ◽  
Vol 60 (2) ◽  
pp. 491-495 ◽  
Author(s):  
Patricia Torres ◽  
Jenny A. Rodríguez ◽  
Luz E. Barba ◽  
Luis F. Marmolejo ◽  
Carlos A. Pizarro
Keyword(s):  
Municipal Wastewater ◽  
Combined Treatment ◽  
Domestic Wastewater ◽  
Anaerobic Treatment ◽  
Uasb Reactor ◽  
Organic Load ◽  
Leachate Treatment ◽  
Wastewater Systems ◽  
Efficient Alternative ◽  
Chemical Inputs

Landfills are among the most affordable and acceptable methods in terms of public health and environmental protection for the final disposal of solid waste. Leachate treatment incorporated into anaerobic domestic wastewater systems could be a viable and efficient alternative which would allow minimizing implementation and operation costs of the landfill, to reduce requirements of chemical inputs such as pH conditioners and phosphorus supply. This study showed the potential of anaerobic treatment in an UASB reactor treating a combination of domestic wastewater and leachate in a 5% volumetric ratio of leachate. Under these conditions the reactor assimilated properly the leachate fraction incorporated. With a HRT of 8 h and a mean volumetric organic load of 2.84 kg m−3 d−1 COD removal efficiencies around 70% were obtained, without inhibition problems; however, the necessity of a complementary treatment for improving carbonaceous and nitrogenous organic matter reduction is evident.

Biological Phosphorus Removal Using a Biofilm Membrane Reactor: Operation at High Organic Loading Rates

1999 ◽  
Vol 40 (4-5) ◽  
pp. 321-329 ◽  
Author(s):  
Pedro A. Castillo ◽  
Simón González-Martínez ◽  
Iñaki Tejero
Keyword(s):  
Phosphorus Removal ◽  
Membrane Reactor ◽  
Synthetic Wastewater ◽  
Organic Load ◽  
Biological Phosphorus Removal ◽  
Organic Loading ◽  
Removal Rates ◽  
Loading Rates ◽  
Biological Phosphorus ◽  
P Removal

This research describes Biological Phosphorus Removal at Organic Loading Rates from 5 to 30 g COD/m2·d using a laboratory scale Sequencing Batch Biofilm Membrane Reactor. The reactor was fed with synthetic wastewater based on sodium acetate with a COD:N:P ratio of 20:5:1. An average PO4-P removal of 72% was observed when the organic load was kept under 15 gCOD/m2·d. Maximum PO4-P removal of 85% was associated with a consumption rate of 700 mgPO4-P/m2·d. Increasing with the organic load, the PO4-P released during the anaerobic phase averages 40% over the influent concentration, showing a maximum value of 107%. Throughout the experiments, overall COD removal rates were above 90%, and the COD uptake during the anaerobic phase ranged between 60 and 80% for organic loading rates under 15 gCOD/m2·d. Simultaneous nitrification and dentrification took place during the transition from aerobic to anaerobic conditions at the beginning of every cycle. Average transformation rates between 0.6 to 2.0 gNH4-N/m2·d and 0.3 to 1.2 gNO3-N/m2·d were observed for organic loading rates under 15 gCOD/m2·d, corresponding to average NH4-N removal rates between 50 and 70%. Average effluent NO3-N ranged between 1.5 and 10.6 mg/l. Phosphorus contents of the biofilm based on dry mass ranged between 4.2 and 5.2%.

scholarly journals Enriching and aggregating purple non-sulfur bacteria in an anaerobic sequencing-batch photobioreactor for nutrient capture from wastewater

2020 ◽  
Author(s):  
Marta Cerruti ◽  
Berber Stevens ◽  
Sirous Ebrahimi ◽  
Abbas Alloul ◽  
Siegfried E. Vlaeminck ◽  
...  
Keyword(s):  
Mixed Culture ◽  
Municipal Wastewater ◽  
Biomass Accumulation ◽  
Amplicon Sequencing ◽  
Stirred Tank ◽  
List Type ◽  
Organic Loading ◽  
Loading Rates ◽  
Sulfur Bacteria ◽  
Ir Light

AbstractPurple non-sulfur bacteria (PNSB), a guild of anoxygenic photomixotrophic organisms, rise interest to capture nutrients from wastewater in mixed-culture bioprocesses. One challenge targets the aggregation of PNSB biomass through gravitational separation from the treated water to facilitate its retention and accumulation, while avoiding the need for membranes. We aimed to produce an enriched, concentrated, well-settling, nutrient-removing PNSB biomass using sequencing batch regimes (SBR) in an anaerobic photobioreactor. The stirred tank was fed with a synthetic influent mimicking loaded municipal wastewater (430-860 mg CODAc LInf-1, COD:N:P ratio of 100:36:4-100:11:2 m/m/m), operated at 30°C and pH 7, and continuously irradiated with infrared (IR) light (>700 nm) at 375 W m-2. After inoculation with activated sludge at 0.1 g VSS L-1, PNSB were rapidly enriched in a first batch of 24 h: the genus Rhodobacter reached 54% of amplicon sequencing read counts. SBR operations at volume exchange ratio of 50% with decreasing hydraulic retention times (48 to 16 h; 1 to 3 cycles d-1) and increasing volumetric organic loading rates (0.2 to 1.3 kg COD m-3 d-1) stimulated the aggregation (compact granules of 50-150 μm), settling (sedimentation G-flux of 4.7 kg h-1 m-2), and accumulation (as high as 3.8 g VSS L-1) of biomass. The sludge retention time (SRT) increased freely from 2.5 to 11 d without controlled sludge wasting. Acetate, ammonium, and orthophosphate were removed simultaneously (up to 96% at a rate of 1.1 kg COD m-3 d-1, 77% at 113 g N m-3 d-1, and 73% at 15 g P m-3 d-1) with a COD:N:P assimilation ratio of 100:6.7:0.9 (m/m/m). Competition for substrate and photons occurred in the PNSB guild. SBR regime shifts sequentially selected for Rhodobacter (90%) under shorter SRT and non-limiting acetate concentrations during reaction phases, Rhodopseudomonas (70%) under longer SRT and acetate limitation, and Blastochloris (10%) under higher biomass concentrations. We highlighted the benefits of a PNSB-based SBR process for biomass accumulation and simultaneous nutrient capture at substantial rates, and its underlying microbial ecology.Graphical abstractHighlightsPNSB were highly enriched (90%) in an anaerobic stirred-tank photobioreactor.The mixed-culture SBR process fostered PNSB biomass aggregation and accumulation.PNSB sludge reached 3.8 g VSS L-1 and a sedimentation G-flux of 4.7 kg h-1 m-2.PNSB enabled a high simultaneous removal of COD (96%), N (77%), and P (73%).Rhodobacter, Rhodopseudomonas, and Blastochloris competed for acetate and photons.

Wastewater treatment in an anaerobic filter using small lava stones as filter media without temperature control

2011 ◽  
Vol 63 (6) ◽  
pp. 1188-1195
Author(s):  
Simón González-Martínez ◽  
Óscar González-Barceló ◽  
Carlos A. Flores-Torres
Keyword(s):  
Municipal Wastewater ◽  
Organic Loading Rate ◽  
The European Union ◽  
Organic Loading ◽  
Removal Rates ◽  
Biological Filtration ◽  
Support Materials ◽  
Loading Rates ◽  
Anaerobic Filter ◽  
Average Size

For their simplicity and using cheap support materials, biological filtration of municipal wastewater can be adequate for developing countries where the legislation is not as strict as in other countries, like the members of the European Union. Biological filters are fixed biomass reactors where the suspended pollutants can easily be retained and the dissolved substances can be transformed by microbial activity. A pilot anaerobic filter was built and filled with lava stones sieved to obtain particles with an average size of 6 mm. The filter was fed with municipal wastewater during 220 days under hydraulic retention times (HRT) of 4.3 and 9.8 hours (average organic loading rates of 0.48 and 1.23 kgCOD/m3 d). The results show that the pH did not change significantly during the process. Lower organic loading rates (higher HRT) resulted in better COD and TSS removal rates. Average biogas composition showed methane to be 67% for the lower organic loading rate and 63% for the higher one. Backwashing with air for 5 minutes every 72 hours did not negatively affect the overall anaerobic process. Average TSS removal was 79 and 73% for the higher and lower HRT (lower and higher organic loading rates), respectively. The overall performance of the anaerobic filter is comparable with the reported values in the literature. The COD and TSS removal rates are slightly inferior to the ones reported in the literature for UASB reactors treating municipal wastewater.

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