Freeze–thaw treatment of RBC sludge from a remote mining exploration facility in subarctic Canada

2011 ◽  
Vol 63 (6) ◽  
pp. 1309-1313 ◽  
Author(s):  
James Diak ◽  
Banu Örmeci ◽  
Corinne Proux
Keyword(s):  
Pilot Scale ◽  
Fecal Coliforms ◽  
Mechanical Equipment ◽  
Nitrogen And Phosphorus ◽  
Sludge Dewatering ◽  
Rotating Biological Contactor ◽  
Ambient Temperatures ◽  
Freeze Thaw ◽  
Solids Concentration ◽  
Mining Exploration

Freeze–thaw conditioning of RBC (Rotating Biological Contactor) sludge was tested using a pilot-scale freezing bed placed in a mobile freezer operated at −10°C. Sludge samples from a remote mining exploration facility were flown in every 2 weeks, and added to the freezing bed in 8 layers of 10 cm thick. Approximately 4 months after the first layer of sludge was added, the pilot unit was removed from the freezer and thawed at ambient temperatures. After one day of thawing, the solids concentration increased from 2.6% to 16.2%. The final cake solids concentration was 21%. Melt water had increasing turbidity, COD, TSS, VSS, nitrogen and phosphorus concentrations during the thawing period. Freeze–thaw conditioning also decreased the initial densities of fecal coliforms and Salmonella in sludge. The results of this study showed that freeze-thaw technology successfully dewatered RBC sludge without the need for mechanical equipment, and is a sustainable option for sludge dewatering in cold and remote regions.

Pilot-scale studies of sludge dewatering in a freezing bed

1991 ◽  
Vol 18 (4) ◽  
pp. 681-689 ◽  
Author(s):  
C. James Martel ◽  
Carl J. Diener
Keyword(s):  
New Hampshire ◽  
Pilot Scale ◽  
Operational Experience ◽  
Sludge Dewatering ◽  
Design Models ◽  
Freeze Thaw ◽  
Front End ◽  
Raw Wastewater ◽  
Aerobically Digested

In 1986, a pilot-scale sludge freezing bed was constructed at the U.S. Army Cold Regions Research and Engineering Laboratory in Hanover, New Hampshire, U.S.A. This bed was operated for the next three years using both anaerobically and aerobically digested sludges. Results indicate that both sludges were effectively dewatered by this process. The maximum depth of sludge frozen during this study was 1.14 m. The final solid contents were 39.3% and 24.5% for anaerobically digested and aerobically digested sludges respectively. The quality of the meltwater from the bed was similar to raw wastewater. The actual depth of sludge frozen and thawed in the bed during each year of operation was very close to that predicted by design models. Operational experience demonstrated the importance of a sand layer at the bottom of the bed for adequate drainage. Also, odors developed when the meltwater was allowed to accumulate in the bed. Odors were not a problem when the meltwater was drained away as quickly as it formed. Both sludges were easily removed with a front-end loader. Key words: sludge freezing bed, freeze–thaw conditioning, freeze–thaw separation, sludge dewatering, freezing bed.

Pathogen Reduction Capabilities of Freeze/Thaw Sludge Conditioning

1992 ◽  
Vol 26 (9-11) ◽  
pp. 2183-2183
Author(s):  
D. F. Sanin ◽  
P. A. Vesilind ◽  
J. J. Martel
Keyword(s):  
Solid Content ◽  
Fecal Coliforms ◽  
Sludge Dewatering ◽  
Indicator Microorganisms ◽  
Freeze Thaw ◽  
Dependent Variables ◽  
Different Temperatures ◽  
Pathogen Reduction ◽  
Sludge Conditioning ◽  
Reduction Capacity

Freeze/thaw conditioning of sludges has been shown to be an effective and economical method of sludge dewatering especially for areas where natural freezing is possible. Freeze treatment dehydrates the sludge particles by freezing the water associated to the floc and upon thawing an easily drainable granular type of material is obtained. The solid content of the freeze/thawed sludge from specially designed freezing beds ranges from 30% to as high as 60%. Pathogen reduction capacity of freeze/thaw conditioning has not been evaluated. The purpose of this study is to determine the variables affecting the pathogen reduction in freeze/thaw sludge conditioning. Previous research has shown that freezing rate, time in the frozen state, and temperature all influence the condition of the freeze/thawed sludge, and these are chosen to be the independent variables of the research. The three microorganisms- salmonella, fecal coliforms and plaque forming units for viruses-are chosen to be the dependent variables, since they best represent the other pathogenic microorganisms. Three different rates, four different temperatures and three different times of freezing are tested for their effects on the reduction of the three selected microorganisms. Results indicate that all of the parameters, time, rate and temperature of freezing have significant effects on the reduction of the indicator microorganisms.

Heterotrophic Kinetic Parameter Estimation for Enhanced Biological Phosphorus Removal Processes Operated in Conventional and Membrane-Assisted Modes

2006 ◽  
Vol 41 (1) ◽  
pp. 72-83 ◽  
Author(s):  
Zhe Zhang ◽  
Eric R. Hall
Keyword(s):  
Parameter Estimation ◽  
Phosphorus Removal ◽  
Growth Yield ◽  
Pilot Scale ◽  
Enhanced Biological Phosphorus Removal ◽  
Biological Phosphorus Removal ◽  
Nitrogen And Phosphorus ◽  
Parameter Values ◽  
The Impact ◽  
Biological Phosphorus

Abstract Parameter estimation and wastewater characterization are crucial for modelling of the membrane enhanced biological phosphorus removal (MEBPR) process. Prior to determining the values of a subset of kinetic and stoichiometric parameters used in ASM No. 2 (ASM2), the carbon, nitrogen and phosphorus fractions of influent wastewater at the University of British Columbia (UBC) pilot plant were characterized. It was found that the UBC wastewater contained fractions of volatile acids (SA), readily fermentable biodegradable COD (SF) and slowly biodegradable COD (XS) that fell within the ASM2 default value ranges. The contents of soluble inert COD (SI) and particulate inert COD (XI) were somewhat higher than ASM2 default values. Mixed liquor samples from pilot-scale MEBPR and conventional enhanced biological phosphorus removal (CEBPR) processes operated under parallel conditions, were then analyzed experimentally to assess the impact of operation in a membrane-assisted mode on the growth yield (YH), decay coefficient (bH) and maximum specific growth rate of heterotrophic biomass (µH). The resulting values for YH, bH and µH were slightly lower for the MEBPR train than for the CEBPR train, but the differences were not statistically significant. It is suggested that MEBPR simulation using ASM2 could be accomplished satisfactorily using parameter values determined for a conventional biological phosphorus removal process, if MEBPR parameter values are not available.

A proposed sustainable BNR plant with the emphasis on recovery of COD and phosphate

2003 ◽  
Vol 48 (1) ◽  
pp. 77-85 ◽  
Author(s):  
X.-D. Hao ◽  
M.C.M. van Loosdrecht
Keyword(s):  
Wastewater Treatment ◽  
Municipal Wastewater ◽  
Water Environment ◽  
Pilot Scale ◽  
Ammonium Oxidation ◽  
Municipal Wastewater Treatment ◽  
Nitrogen And Phosphorus ◽  
Water Problems ◽  
Sustainable Wastewater Treatment ◽  
The Impact

Water problems have to be solved in an integrated way, and sustainability has become a major issue. For this reason, developing more sustainable wastewater treatment processes is needed. New discoveries and good understanding on microbial conversions of nitrogen and phosphorus make more sustainable processes possible. New options for decentralized sustainable sanitation are generally compared to conventional sewage systems, we think that for a proper comparison also innovative centralized treatment schemes should be evaluated. In this article, a more sustainable WWTP is proposed for municipal wastewater treatment, mainly based on the principles of denitrifying dephosphatation and anaerobic ammonium oxidation (ANAMMOX). The proposed system consists of a first stage of the A/B process in which maximal sludge production is achieved. In this way, COD is regained as sludge for methanation. The following BCFS® and CANON processes can remove N and P with minimal or no COD need. As a potential fertiliser, struvite can easily be removed from the sludge water by adding magnesium compounds. A case study is done on the basis of the mass balance over the proposed plant. The effluent from the system has a good quality to be recycled. This could also make a contribution to meeting the world's water needs and lessening the impact on the world's water environment. Since all the separate units are already applied or tested on pilot-scale, no problems for technical implementation are foreseen.

VERMICOMPOSTING TECHNOLOGY FOR STABILIZING THE SEWAGE SLUDGE FROM RURAL WASTE WATER TREATMENT PLANTS

2008 ◽  
Vol 3 (1) ◽  
Author(s):  
V. Lina Cardoso ◽  
C. Esperanza Ramírez ◽  
E. Violeta Escalante
Keyword(s):  
Rural Communities ◽  
Sewage Sludge ◽  
Low Cost ◽  
Waste Water Treatment ◽  
Treatment Plant ◽  
Microbiological Quality ◽  
Fecal Coliforms ◽  
Nitrogen And Phosphorus ◽  
Sludge Management

There are problems associated with sludge management in small treatment plants (<10 L/s) located in rural communities, due to costly conventional technology for sludge stabilization. Many of these plants have only sludge drying beds. Mexican Institute of Water Technology has proposed developing suitable low-cost technologies, one of which is vermicomposting a biodegradation system using earthworms of the species Eisenia foetida (earthworm) which stabilize sludge and reduce its pathogenicity. The objective of this work is to present two case studies where vermicomposting technology has been applied in Mexico. The first study corresponds to a plant where 4.8 m3/month of sludge are produced; for these wastes, a vermicomposting system was built and installed. The second study is a treatment plant where 9 m3/month of sludge are produced; experimental tests were conducted with sludge and water hyacinth and a vermicomposting system was designed. The vermicomposts were analyzed using parameters defined by Mexican standards. In regards to stabilization, TVS was reduced by 38% and the microbiological quality of the vermicompost was Class A and B, with a reduction in fecal coliforms and Helminth eggs according to NOM-004-SEMARNAT-2002. A CRETI (Corrosivity, Reactivity, Explosivity, Toxicity and Ignitability) analysis (NOM-052-SEMARNAT-2005) was used to show that the process reduced the concentration of releasable sulfides. The agronomic quality of the vermicompost exhibited a high content of organic matter comparable to many organic manures and high content of nutrients such as nitrogen and phosphorus. It is concluded that it is possible to improve the conditions of sewage sludge management in small plants of rural communities with a minimum investment (less than $10,000.00 USD) and with a requirement of a minimum area of 60 to 70 m2 for a production of less than 9 m3/month of dehydrated sludge (80% humidity).

scholarly journals Can a one-sampling campaign produce robust results for water quality monitoring? A case of study in Itupararanga reservoir, SP, Brazil

2016 ◽  
Vol 28 (0) ◽  
Author(s):  
Frederico Guilherme de Souza Beghelli ◽  
Marcelo Luiz Martins Pompêo ◽  
Mônica Páscoli ◽  
Vivian Silva Lira ◽  
Renata de Lima ◽  
...  
Keyword(s):  
Benthic Macroinvertebrates ◽  
Water Quality Monitoring ◽  
Poor Quality ◽  
Fecal Coliforms ◽  
Toxic Substances ◽  
Nitrogen And Phosphorus ◽  
Biological Variables ◽  
Sampling Campaign ◽  
Sampling Points ◽  
High Concentrations

Abstract Aim: The aim of this study was to conduct a rapid and comprehensive analysis of the reservoir using physical, chemical and biological variables comprising water and sediment as also to verify if a one-sampling campaign can produce information that is robust enough for monitoring purposes. Methods One-sampling campaign was performed along the central body of Itupararanga reservoir comprising five sampling points. The following physico-chemical and biological variables were measured in each of them from water samples: temperature, pH, concentration of dissolved oxygen, electric conductivity, suspended matter, total nitrogen and phosphorus and fecal coliforms. A genotoxicity assay with Allium cepa was also performed with water from each one of the five sampling points. As a complement, the phytoplankton and benthic macroinvertebrates communities were also analyzed in the two most distant sampling points (P1 and P5). Results Results indicate a scenario with eutrophication and toxicity. High concentrations of fecal coliforms were recorded and there is a worrying prevalence of cyanobacteria - potential toxin producers - in phytoplankton community. Benthic macroinvertebrates analysis suggests poor quality of the water and sediments. Genotoxicity tests suggest the presence of toxic substances along the waterbody. Conclusions It is concluded that Itupararanga reservoir has water with poor quality that could be related to the land uses around the reservoir. The comprehensive approach performed here - where distinct sources of monitoring variables was considered - despite the rapid protocol (one campaign), was enough to respond to the distinct anthropic impacts received by the reservoir. Considering it, this approach is recommended as a rapid diagnostic tool.

Experimental and modeling evaluation of upward and downward velocities in the coaxial flotation column

2001 ◽  
Vol 43 (8) ◽  
pp. 195-201 ◽  
Author(s):  
K. Park ◽  
J.-M. Cho ◽  
J. Oh ◽  
K. Chung
Keyword(s):  
Removal Efficiency ◽  
Pilot Scale ◽  
Coaxial Cylinder ◽  
Treated Water ◽  
Flotation Column ◽  
Solids Loading ◽  
Solids Concentration ◽  
Upward Velocity ◽  
Solids Removal

This study was conducted to show the influence of upward velocity in the inner column and downward velocity in the outer column of the coaxial cylinder-type flotation column on the solids removal efficiency, solids concentration in the treated water, and so on. The SIMPLE (Semi-Implicit Method for Pressure Linked Equation) solution was applied to the coaxial flotation column to simulate the velocity vectors of the elements of water flowing in the column. The effects of solids loading and residence time in the agglomerate separation zone on the solids removal efficiency were also tested. In the pilot scale coaxial DAF column experiments with solids concentration of 1,000–2,000 mg of SS per liter and solids loading less than 350 kg/m2/day, approximately 90% of the solids removal efficiencies were obtained using the upward velocity of up to 110 cm/min in the contact zone of the inner column and the downward velocity of up to 30 cm/min in the outer column. In the simulation, similar results were observed as in the experiments. The solids loading in the excess of 350 kg/m2/day caused the instability of the sludge float layer and aggravated the quality of the treated water.

Toxicity assays and their evaluation on organic polymer flocculants used for municipal sludge dewatering

1998 ◽  
Vol 38 (7) ◽  
pp. 207-215 ◽  
Author(s):  
H. Takigami ◽  
N. Taniguchi ◽  
Y. Shimizu ◽  
S. Matsui
Keyword(s):  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Algal Growth ◽  
Pilot Scale ◽  
Organic Polymer ◽  
Municipal Sludge ◽  
Sludge Dewatering ◽  
Algal Toxicity ◽  
Reproduction Tests

The toxicity of organic polymer flocculants used for the dewatering of municipal sludge was evaluated by using two different toxicity assays: the Closterium ehrenbergii algal toxicity test and the Bacillus subtilis rec-assay. The algal toxicity of the effluents from a pilot-scale sewage treatment plant was investigated with and without the addition of a flocculant (0, 0.05, 0.10 and 0.20 mg/L). No clear evidence on the toxicity caused by the flocculant was observed on both asexual and sexual reproduction tests of C. ehrenbergii. It was also found that the algal growth inhibition of various types of flocculants (i.e., cationic, anionic, amphoionic and non-ionic) was in the order of 1 to 20 mg/L, which was mainly due to a molecular weight (MW) fraction of greater than 100,000. The results of the B. subtilis rec-assay for these flocculants indicated that eight out of ten cationic flocculants caused the direct DNA damage with LC50 =0.1 to 10 mg/L. One of the genotoxic flocculants was also fractionated into their components by MW. The experimental results showed that the lethal effects were mainly contributed by the polymer fraction of MW greater than 100,000, although the genotoxicity was not detected in that fraction. Therefore, the detected genotoxicity of the flocculants could be caused by the combined effects of various components, such as polymers, oligomers, monomers and additives.

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