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.

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.

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.

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.

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 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.

RESEARCH AND EVALUATE TREATMENT EFFICIENCY ON TAPIOCA PROCESSING INDUSTRIAL WASTEWATER BY AEROBIC BIOFILTER TECHNOLOGY WITH VARIOUS MATERIALS

2010 ◽  
Vol 13 (3) ◽  
pp. 54-66
Author(s):  
Phuong Thi Thanh Nguyen ◽  
Phuoc Van Nguyen ◽  
Anh Cam Thieu
Keyword(s):  
Wastewater Treatment ◽  
Industrial Wastewater ◽  
Utilization Rate ◽  
Organic Loading ◽  
Treatment Efficiency ◽  
Research Results ◽  
Loading Rates

This study was performed to evaluate the efficiency of tapioca processing wastewater treatment using aerobic biofilter with variety of biofilter media: coir, coal, PVC plastic and Bio - Ball BB15 plastic. Research results in the lab demonstrated all four aerobic biofilter models processed can treated completely N and COD which COD reached 90-98% and N reached 61-92%, respectively, at the organic loading rates in range of 0.5, 1, 1.5 and 2 kgCOD/m3.day. The results identified coir filter was the best in four researched materials with removal COD and specific substract utilization rate can reach 98%, and 0.6 kg COD/kgVSS.day. Research results open the new prospects for the application of the cheap materials, available for wastewater treatment.

Stabilization of Organic Carbon and Nitrogen in Consolidating Benthal Deposits

1985 ◽  
Vol 17 (6-7) ◽  
pp. 929-940 ◽  
Author(s):  
C. W. Bryant ◽  
L. G. Rich
Keyword(s):  
Organic Carbon ◽  
Model Verification ◽  
Volatile Acid ◽  
Free Energies ◽  
Organic Loading ◽  
Carbon And Nitrogen ◽  
Loading Rates ◽  
Degradation Reactions ◽  
The Individual ◽  
Organic Deposits

The objective of this research was to develop and validate a predictive model of the benthal stabilization of organic carbon and nitrogen in deposits of waste activated sludge solids formed at the bottom of an aerated water column, under conditions of continual deposition. A benthal model was developed from a one-dimensional, generalized transport equation and a set of first-order biological reactions. For model verification, depth profiles of the major interstitial carbon and nitrogen components were measured from a set of deposits formed in the laboratory at 20°C and a controlled loading rate. The observed sequence of volatile acid utilization in each benthal deposit was that which would be predicted by the Gibbs free energies of the individual degradation reactions and would be controlled by the reduction in interstitial hydrogen partial pressure with time. Biodegradable solids were solubilized rapidly during the first three weeks of benthal retention, but subsequent solubilization occurred much more slowly. The benthal simulation effectively predicted the dynamics of consolidating, organic deposits. Simulation of organic loading rates up to 250 g BVSS/(m2 day) indicated that the stabilization capacity of benthal deposits was far above the range of organic loading rates currently used in lagoon design.

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