Increasing microbial activity in thermophilic anaerobic digestion of physicochemical sludge

2006 ◽  
Vol 54 (2) ◽  
pp. 245-251
Author(s):  
A. Tinajero ◽  
A. Noyola
Keyword(s):  
Biogas Production ◽  
Treatment Plant ◽  
Primary Treatment ◽  
Fecal Coliforms ◽  
Salmonella Spp ◽  
Digested Sludge ◽  
Class A ◽  
Effect Of Additives ◽  
Thermophilic Anaerobic Digestion ◽  
Chemically Enhanced Primary Treatment

Two thermophilic lab-scale reactors of 5 L were operated on a daily fed basis. Digester T1 received raw sludge (control) and digester T2 was fed with raw sludge plus metallic micronutrients and a bacilli additive. Raw sludge was obtained from a municipal chemically enhanced primary treatment plant. The effect of additives was clear on methane production, since on day 50, digester T2 produced 900 ml more methane than T1, an increase of 64%. On day 80, T2 reached twice the production of biogas of T1. Volatile solid removal (% VSR) in T2 increased to 29%; while T1 achieved only 15%. Acetic acid concentration in T2 diminished to 100 mg/L, which related to the higher biogas production. Based on the Mexican biosolids standard, the digested sludge reached Class A biosolids, in both digesters: fecal coliforms were reduced to less than 1000 MPN/gTS; Salmonella spp was totally eliminated and helminth egg counts were lower than one viable egg per gram of total solids.

scholarly journals Influence of chemically enhanced primary treatment on anaerobic digestion and dewaterability of waste sludge

2017 ◽  
Vol 76 (7) ◽  
pp. 1629-1639 ◽  
Author(s):  
G. Kooijman ◽  
M. K. De Kreuk ◽  
J. B. van Lier
Keyword(s):  
Anaerobic Digestion ◽  
Biogas Production ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Primary Treatment ◽  
Hydrolysis Rate ◽  
Biological Degradation ◽  
Digested Sludge ◽  
N Removal ◽  
Chemically Enhanced Primary Treatment

To lower energy consumption at a sewage treatment plant (STP), primary settling could be enhanced to direct more chemical oxygen demand (COD) to anaerobic digestion (AD) for increased biogas production and decreased aeration. Primary settling can be chemically enhanced by applying flocculation aids (FAs). FAs are refractory compounds that may affect all sludge treatment facilities. In this study the consequences are investigated of the application of FAs for chemically enhanced primary treatment (CEPT) on AD and subsequent dewatering of digested sludge in a conventional STP. It was found that FAs maintain their effect throughout all sludge processing facilities. With CEPT, more readily degradable solids were removed, resulting in a higher bio methane potential of the primary sludge. In AD, FAs lowered the viscosity; meanwhile an increased hydrolysis rate was observed. But FAs also partially irreversibly bound substrate in such way that it is not available for biological degradation anymore. In subsequent dewatering of digested sludge, a higher dry solids concentration was observed with CEPT. A computer simulation showed that in a conventional STP, CEPT would not be economically feasible. However, several benefits were discussed that can make CEPT an interesting option for future low COD/N-tolerant STPs with, for example, Anammox processes for N removal.

Single-stage Sequencing Batch Process for Producing Class A Biosolids from AD Effluent at Terminal Island Treatment Plant

2006 ◽  
Vol 1 (4) ◽  
Author(s):  
Huub H.J. Cox ◽  
Steve Fan ◽  
Reza Iranpour
Keyword(s):  
Fecal Coliform ◽  
Treatment Plant ◽  
Batch Process ◽  
Single Stage ◽  
Fecal Coliforms ◽  
Class A ◽  
Truck Loading ◽  
Train Operation ◽  
Plant Control ◽  
Class A Biosolids

Terminal Island Treatment Plant converted its digesters to thermophilic operation with the objective to comply with the U.S. EPA Part 503 Biosolids Rule requirements for Class A biosolids. The following processes were tested: a) single-stage continuous; b) two-stage continuous; c) single-stage sequencing batch. Salmonella sp. were always non-detect in digester outflows (<3 MPN/4 g dry wt), whereas fecal coliform densities were usually below the Class A limit of 1000 MPN/g dry wt. However, the recurrence of fecal coliforms in post-digestion caused non-compliance with the Class A limit at the truck loading facility as the last point of plant control for compliance. After several design modifications of the post-digestion train, operation of the digesters as sequencing batch digesters according to the time-temperature requirement of Alternative 1 of the Part 503 Biosolids Rule achieved compliance for both Salmonella sp. and fecal coliforms at the last point of plant control (truck loading facility).

Characterization of raw sludge, chemically modified sludge and anaerobically digested sludge in Hong Kong

1998 ◽  
Vol 38 (2) ◽  
pp. 25-32 ◽  
Author(s):  
C. W. Chu ◽  
C. S. Poon ◽  
R. Y. H. Cheung
Keyword(s):  
Hong Kong ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Chemical Properties ◽  
Primary Treatment ◽  
Digested Sludge ◽  
Total N ◽  
Chemically Modified ◽  
Anaerobically Digested Sludge

Chemically Enhanced Primary Treatment (CEPT) or Chemically Assisted Primary Sedimentation (CAPS) is being employed at the new sewage work on Stonecutters Island as part of the Strategic Sewage Disposal Scheme (SSDS) in Hong Kong. CAPS involves the use of chemical coagulants (such as lime or ferric chloride) to induce coagulation or flocculation and let these finely-divided particles form large aggregates (floc) so that they can settle out within a reasonable period of time. In this study, five sludge samples collected from different sewage treatment plants in Hong Kong were physically and chemically characterized. They were chemically modified sludge from Stonecutters Island (CAPS) raw sludge from Tai Po and Yuen Long Sewage Treatment Plant (STP) (rTP & rYL) and anaerobically digested sludge from Tai Po and Yuen Long STP (dTP & dYL). It was found that CAPS sludge was better than other 4 sludge samples in terms of settleability and dewaterability. CAPS sludge contained significant higher amounts (p<0.01) of extractable compounds than other sludges (except NO3− for dTP, NH4+ and PO43− for dYL). The concentration of total N and P in CAPS sludge were significantly higher (p<0.01) than other sludges (except dYL). The concentrations of total Cu, Pb, Ni, Cd, Cr and K in the CAPS sludge were also significantly higher (p<0.01) than other sludge samples. Most of the metals (Cr, Pb, Cr and Zn) in CAPS sludge were associated with the organically-bounded phase. It is concluded that there are significant differences in both physical and chemical properties between the chemically modified sludge and biological treated sludges.

Solving fecal coliform growth/reactivation in biosolids during full-scale post-digestion processes

2005 ◽  
Vol 52 (1-2) ◽  
pp. 283-288 ◽  
Author(s):  
R. Iranpour ◽  
R. Palacios ◽  
H.H.J. Cox ◽  
V. Abkian
Keyword(s):  
Los Angeles ◽  
Fecal Coliform ◽  
Treatment Plant ◽  
Pilot Scale ◽  
Full Scale ◽  
Fecal Coliforms ◽  
Anaerobic Digesters ◽  
Plant Conversion ◽  
Thermophilic Anaerobic Digestion ◽  
The City

Fecal coliform recurrence has been observed at the City of Los Angeles Hyperion Treatment Plant during pilot-scale experiments with a designated thermophilic battery of six anaerobic digesters, while other digesters were still at a mesophilic temperature. Several lab and full-scale experiments indicated the following possible causes of the growth/reactivation of fecal coliforms in post-digestion: a) contamination of thermophilically digested biosolids with mesophilically digested biosolids; b) a large drop in the biosolids temperature between the centrifuges and silos, which could have allowed the reactivation and/or growth of fecal coliforms. These were resolved by the full plant conversion to thermophilic anaerobic digestion and design modifications of the post-digestion train.

Dewatering and disinfection of aerobic and anaerobic sludge using an electrokinetic (EK) system

2008 ◽  
Vol 57 (2) ◽  
pp. 231-236 ◽  
Author(s):  
J. Huang ◽  
M. Elektorowicz ◽  
J. A. Oleszkiewicz
Keyword(s):  
Low Voltage ◽  
Chloride Ions ◽  
Fecal Coliforms ◽  
Anaerobic Sludge ◽  
Voltage Gradient ◽  
Salmonella Spp ◽  
Digested Sludge ◽  
Volatile Solids ◽  
Anaerobically Digested Sludge ◽  
Solids Content

The objectives of the study were to upgrade sewage sludge to Class A Exceptional Quality biosolids (as defined by US EPA) using an electrokinetics dewatering system. The pathogens monitored were Salmonella spp, and fecal coliforms (FC). Ten bench-scale electrokinetic cells were set up for the disinfection of the following sludges: primary, secondary (attached growth culture and suspended culture), and anaerobically digested sludge. A conditioning liquid was also added to five cells. Blower system to aid in dewatering and drying was used in in four EK cells. Sludge characteristics such as water content, volatile solids content, sulfate and chloride ions concentrations, FC and Salmonella spp. before and after the tests were monitored. The highest total solids content (98% TS) was achieved in the cell with the low voltage gradient, in the presence of the conditioner and with the blower system. An average reduction by 50% of volatile solids was observed. The highest, 11 log-reduction of Salmonella spp. was observed in a cell with anaerobically digested sludge. No fecal coliforms were observed in any of the cells after EK treatment.

Microbiological and parasitological quality of ground beef sold in Aracaju-SE

2015 ◽  
Vol 6 (2) ◽  
pp. 15
Author(s):  
Sydney Correia Leao ◽  
Debora Machado Barreto ◽  
Viviane Da Costa Ribeiro ◽  
Roneval Felix De Santana ◽  
Cláudia Moura De Melo ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Ascaris Lumbricoides ◽  
Ground Beef ◽  
Fecal Coliforms ◽  
Salmonella Spp ◽  
Class A ◽  
Low Levels ◽  
The City ◽  
Butcher Shops

<p><strong><em>The goal of this work was to verify the presence of microorganisms and parasites in the ground beef sold in the city of Aracaju, Sergipe, in addition to compare the contamination in butcher shops and supermarkets in neighborhoods Class A and D. We collected 16 samples of 100 gram in triplicate (m=48) and analyzed the bacteria Staphylococcus aureus, Salmonella spp. coliforms total and thermotolerants, molds and yeasts, and parasites. It was observed that the samples are contaminated by these microorganisms examined with high total and fecal coliforms, Salmonella spp. (25%), low levels of S. aureus, molds and yeasts, in addition to the detection of Ascaris lumbricoides, larvae of flies, mites and plant artifacts.</em></strong></p>

Thermophilic-Anaerobic Digestion to Produce Class A Biosolids: Initial Full-Scale Studies at Hyperion Treatment Plant

2006 ◽  
Vol 78 (2) ◽  
pp. 170-180 ◽  
Author(s):  
R. Iranpour ◽  
H.H.J. Cox ◽  
S. Oh ◽  
S. Fan ◽  
R.J. Kearney ◽  
...  
Keyword(s):  
Anaerobic Digestion ◽  
Treatment Plant ◽  
Full Scale ◽  
Class A ◽  
Thermophilic Anaerobic Digestion ◽  
Class A Biosolids

Extending thermophilic anaerobic digestion for producing class a biosolids at the greater vancouver regional districts annacis island wastewater treatment plant

1998 ◽  
Vol 38 (8-9) ◽  
pp. 409-416 ◽  
Author(s):  
Steve Krugel ◽  
Leslie Nemeth ◽  
Craig Peddie
Keyword(s):  
Wastewater Treatment ◽  
Anaerobic Digestion ◽  
Treatment Plant ◽  
Secondary Treatment ◽  
Class A ◽  
Innovative Process ◽  
Thermophilic Anaerobic Digestion ◽  
Extended Operation ◽  
Flow Through ◽  
Bleed Through

The Greater Vancouver Regional District (GVRD) is a major regional agency managing wastewater collection and treatment for Vancouver, Canada and surrounding municipalities. As part of their $ 600 million program to upgrade 2 major plants to secondary treatment, the GVRD was faced with the requirement to produce a treated biosolids meeting the equivalent of a U.S. EPA Class A product to assure success of their new biosolids beneficial use program. Various alternatives to achieve a Class A product were evaluated in detail. The GVRD selected a new and innovative process which they termed extended thermophilic anaerobic digestion. The characteristics of this process which help achieve required pathogen kills are the thermophilic operating temperatures and the series operation of reactors, cutting the bleed-through of pathogens observed in conventional complete mix systems. The new thermophilic digesters have been in operation since 1996 and the flow-through vessels required to complete “extended” operation will be complete in late 1998.

Removal of fecal indicator organisms and parasites (fecal coliforms and helminth eggs) from municipal biologic sludge by anaerobic mesophilic and thermophilic digestion

2001 ◽  
Vol 44 (4) ◽  
pp. 97-101 ◽  
Author(s):  
M. Rojas Oropeza ◽  
N. Cabirol ◽  
S. Ortega ◽  
L. P. Castro Ortiz ◽  
A. Noyola
Keyword(s):  
Treatment Plant ◽  
Anaerobic Treatment ◽  
Fecal Coliforms ◽  
Anaerobic Sludge ◽  
Indicator Organisms ◽  
Fecal Indicator ◽  
Class A ◽  
Helminth Eggs ◽  
Start Up ◽  
Thermophilic Digestion

In this work, two egg-shaped, 5L-volume, anaerobic sludge digesters were used, one under mesophilic conditions (35°C, M1), and the other under thermophilic conditions (55°C, T1). Both digesters were fed with the purged sludge from an anaerobic treatment plant (start-up period) and from an activated sludge plant (stabilization period), treating municipal wastewaters. The purpose of the study was to establish the technical feasibility of the anaerobic thermophilic sludge treatment comparatively, during the stages of start-up and stabilization of the process, for removing pathogenic microorganisms and parasites efficiently. The results show that, in both stages, the anaerobic thermophilic digester presents higher efficiency on the removal of pathogens and parasites, than the mesophilic digester. Anaerobic thermophilic digestion is close to complying with the EPA (1996) limits for “Class A” type biosolids, referring to the number of parasitic helminth eggs (0.25 HELarval/gTS), and to the pathogen indicator fecal coliforms (&lt;1000 MPN/gTS). Therefore, the results show that thermophilic anaerobic digestion of biologic sludge may be considered as a suitable technology for the production of Class A biosolids, for further use in agriculture without restrictions.

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