Polyhydroxyalkanoates production by activated sludge in a SBR using acetate and propionate as carbon sources

2004 ◽  
Vol 50 (10) ◽  
pp. 189-194 ◽  
Author(s):  
P.C. Lemos ◽  
L.S. Serafim ◽  
M.A.M. Reis
Keyword(s):  
Carbon Sources ◽  
Dry Weight ◽  
Operating Conditions ◽  
Batch Reactors ◽  
Sequencing Batch Reactors ◽  
Cell Content ◽  
A Value ◽  
Substrate Feeding ◽  
Commercial Applications ◽  
Processing Properties

In this work, sludge was submitted to aerobic dynamic substrate feeding. Two sequencing batch reactors were operated, with acetate or propionate as carbon substrates. When acetate was used the system only produced a homopolymer of polyhydroxybutyrate (PHB). In order to maximize the PHB production, tests with different concentrations of acetate and ammonia were preformed. The best results (67.2% of PHB by cell dry weight) were obtained for 0.7 Nmmol/l of ammonia and 180 Cmmol/l of acetate. The PHB cell content was further improved by pupulse addition of substrate, three times 60 Cmmol/l of acetate, reaching a value of 78.5%. Propionate can be used as a precursor for hydroxyvalerate. In conjunction with other substrates, it allows for the formation of copolymers, which present better processing properties on commercial applications. Tests with different concentrations of propionate and ammonia were performed. Under the operating conditions used, the maximum PHA accumulated inside cells was 34.8%, with 30 Cmmol/l of propionate and no ammonia.

Balancing yield, kinetics and cost for three external carbon sources used for suspended growth post-denitrification

2009 ◽  
Vol 60 (10) ◽  
pp. 2485-2491 ◽  
Author(s):  
Y. Mokhayeri ◽  
R. Riffat ◽  
S. Murthy ◽  
W. Bailey ◽  
I. Takacs ◽  
...  
Keyword(s):  
Wastewater Treatment Plants ◽  
Carbon Sources ◽  
The United States ◽  
Batch Reactors ◽  
Sequencing Batch Reactors ◽  
Process Step ◽  
Stringent Limit ◽  
Receiving Waters ◽  
Set Up

Facilities across North America are designing plants to meet stringent limit of technology (LOT) treatment for nitrogen removal. In the Mid-Atlantic region of the United States, this is in response to the Chesapeake Bay Agreement, which limit effluent total nitrogen discharges from wastewater treatment plants to between 3–5 mg/L. Since denitrification is crucial for the removal of nitrogen, maximizing this process step will result in a decrease in nutrient load to the receiving waters. Of particular interest is the use of an alternate external carbon source to replace the most commonly used carbon, methanol. Three external carbon sources were evaluated in this study including: methanol, ethanol and acetate at 13°C. The aim of this study was to evaluate the relative benefits and constraints for using these three carbon types. Laboratory scale Sequencing Batch Reactors (SBRs) were set up to grow and acclimate carbon free biomass to the specified substrate while in-situ Specific Denitrification Rates (SDNRs) were conducted concurrently. The results suggest that the SDNRs for acetate (31.0 ± 4.6 mgNO3-N/gVSS/hr) and ethanol (29.6 ± 5.6 mgNO3-N/gVSS/hr) are higher than that for methanol (10.1 ± 2.5 mgNO3-N/gVSS/hr). The yield coefficients in g COD/g COD were observed to follow a similar trend with values of 0.45 ± 0.05 for methanol, 0.53 ± 0.06 for ethanol and 0.66 ± 0.06 for acetate.

The effect of anoxic selectors on sludge bulking

2004 ◽  
Vol 50 (6) ◽  
pp. 261-268 ◽  
Author(s):  
M.V. Tampus ◽  
A.M.P. Martins ◽  
M.C.M. van Loosdrecht
Keyword(s):  
Storage Capacity ◽  
Volume Index ◽  
Feeding Pattern ◽  
Batch Reactors ◽  
Substrate Uptake ◽  
Sequencing Batch Reactors ◽  
Floc Structure ◽  
Substrate Feeding ◽  
Substrate Uptake Rate ◽  
Sludge Settleability

The effect of the substrate feeding pattern on sludge settleability in denitrifying systems was investigated. The feeding pattern was simulated in two sequencing batch reactors (SBR). SBR1 simulates a system with a limiting substrate (acetate) and a non-limiting electron acceptor (nitrate), while SBR2 simulates the opposite condition. Sludge volume index (SVI) was the main observed parameter. The stoichiometry, substrate uptake rate, storage capacity as well as sludge morphology and mixed culture population dynamics were also determined. Results show that independent of the feeding pattern, the settleability of the sludge remained good (SVI ≈ 50 mL/g) and stable. Neither the concentration of the acetate nor of the nitrate offered any limitations on sludge settleability, assuring that a good bio-P activity is present in nitrate limiting systems. Filamentous bacteria belonging to the TM group were usually present, although in low numbers. Despite the diffused, irregularly shaped and open floc structure, good settleability was observed. The results obtained were in line with the hypothesis on diffusion based selection.

Post Treatment of Anaerobic Effluent Using Sequencing Batch Reactors

1989 ◽  
Vol 21 (4-5) ◽  
pp. 23-28
Author(s):  
Kean Kee Chin
Keyword(s):  
Suspended Solids ◽  
Loading Rate ◽  
Operating Conditions ◽  
Oil Refinery ◽  
Batch Reactors ◽  
Sequencing Batch Reactors ◽  
Anaerobic Reactors ◽  
Field Unit ◽  
Solids Removal ◽  
Oil Refinery Wastewater

A 150ℓ field unit and two 7.5ℓ laboratory scale sequencing batch reactors (SBRs) were used to polish edible oil refinery wastewater pretreated by attached film anaerobic reactors. SBRs performed well with respect to COD and suspended solids removal. At a loading rate of less than 2 kg COD/m3-d more than 90% COD removal efficiency was achieved. Solids settling was good with SVI generally less than 160. The system showed stability under large variations of organic loading and operating conditions. A significant amount of COD was removed during the long filling and anoxic period.

Sequencing batch reactor as a post-treatment of anaerobically treated dairy effluent

2006 ◽  
Vol 54 (2) ◽  
pp. 199-206 ◽  
Author(s):  
A. Benítez ◽  
A. Ferrari ◽  
S. Gutierrez ◽  
R. Canetti ◽  
A. Cabezas ◽  
...  
Keyword(s):  
Batch Reactor ◽  
Anaerobic Treatment ◽  
Post Treatment ◽  
Operating Conditions ◽  
Batch Reactors ◽  
Sequencing Batch Reactors ◽  
Operational Parameters ◽  
Reactor Operation ◽  
Set Up ◽  
The Stability

Wastewater from dairy industries, characterized by its high COD content and relative high COD/TKN ratio, requires post-treatment after anaerobic treatment to complete the removal of organic matter and nutrients. Due to its simplicity, robustness and low maintenance costs, sequencing batch reactors (SBR) result in an attractive system, especially in case of small dairy industries in order to comply with the emission standards. The goal of this work was to determine the operational parameters, optimize the performance, and study the stability of the microbial population of a SBR system for the post-treatment of an anaerobic pond effluent. High and stable removal of COD and TKN was achieved in the reactor, which can easily be set up in dairy industries. An active nitrifying population was selected during reactor operation and maintained relatively stable, while the heterotrophic (total and denitrifying) communities were more unstable and susceptible to changes in the operating conditions.

Methane production from ethanol co-products in anaerobic SBRs

2008 ◽  
Vol 58 (4) ◽  
pp. 789-793 ◽  
Author(s):  
D. P. Cassidy ◽  
P. J. Hirl ◽  
E. Belia
Keyword(s):  
Ethanol Production ◽  
Methane Production ◽  
Fossil Fuel ◽  
Operating Conditions ◽  
Batch Reactors ◽  
Sequencing Batch Reactors ◽  
Methane Recovery ◽  
Wide Range ◽  
The Cost ◽  
Condensed Distillers Solubles

Methane production from condensed distillers' solubles (CDS, or syrup), a co-product of ethanol production, was studied in 2-l anaerobic sequencing batch reactors (ASBRs) under 10 different operating conditions. Methane production and COD removal were quantified under steady state conditions for a wide range of operating parameters. COD removals of 62–96% were achieved at OLRs ranging from 1.5–22.2 g COD l−1 d−1, SRTs from 8–40 d, and F/M ranging from 0.37–1.95 g COD g−1 VSS d−1. The methane content of the biogas varied from 57–71% with 0.27 l CH4 produced per g of COD removed. Approximately 54% of the COD fed to the ASBRs, and 83% of the COD removed in the ASBRs was converted to methane. Microbial yield (Y) and decay (b) constants were determined to be approximately Y = 0.127 g VSS g−1 COD removed and b = 0.031 d−1, respectively. Methane recovery from ethanol co-products can reduce the cost and the fossil fuel consumption of ethanol production.

Use of external carbon sources derived from biowaste for short-cut nutrient removal from anaerobic effluents

2014 ◽  
Vol 69 (9) ◽  
pp. 1853-1858 ◽  
Author(s):  
Evina Katsou ◽  
Nicola Frison ◽  
Simos Malamis ◽  
Francesco Fatone
Keyword(s):  
Acetic Acid ◽  
Nutrient Removal ◽  
Carbon Sources ◽  
Phosphorus Uptake ◽  
Upflow Anaerobic Sludge Blanket ◽  
Anaerobic Sludge ◽  
Batch Reactors ◽  
Sequencing Batch Reactors ◽  
Fermentation Liquid ◽  
Anaerobic Sludge Blanket

This work evaluated the use of different external carbon sources to promote the via-nitrite nutrient removal from anaerobic effluents. The carbon sources consisted of fermentation liquid produced from the organic fraction of municipal solid waste (OFMSW FL), drainage liquid produced from OFMSW, fermentation liquid produced from vegetable and fruit waste (VFW FL) and acetic acid. Denitritation and phosphorus uptake via nitrite were evaluated in two sequencing batch reactors, one treating the anaerobic supernatant produced from the co-digestion of OFMSW and activated sludge (highly nitrogenous anaerobic effluent – HNAE), and the other one treating the weakly nitrogenous anaerobic effluent (WNAE) from an upflow anaerobic sludge blanket reactor. The use of OFMSW FL to treat HNAE resulted in high nitrite (27 mgN/(gVSS·h) (VSS – volatile suspended solids) and phosphate uptake (15 mgP/gVSS·h). In the WNAE, nutrient kinetics were much slower. The use of acetic acid and VFW FL performed poorly, while the use of OFMSW FL, which was rich in butyric acid and propionic acid, resulted in significant nutrient removal (7 mgN/gVSS·h and 6 mgP/gVSS·h). The economic evaluation showed that the use of OFMSW FL is a less expensive option than the acetic acid use.

Sign in / Sign up

Export Citation Format

Share Document