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.

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.

scholarly journals A Comparison of Two-Stage and Traditional Co-Composting of Green Waste and Food Waste Amended with Phosphate Rock and Sawdust

2021 ◽  
Vol 13 (3) ◽  
pp. 1109
Author(s):  
Edgar Ricardo Oviedo-Ocaña ◽  
Angélica María Hernández-Gómez ◽  
Marcos Ríos ◽  
Anauribeth Portela ◽  
Viviana Sánchez-Torres ◽  
...  
Keyword(s):  
Organic Matter ◽  
Product Quality ◽  
Food Waste ◽  
Phosphate Rock ◽  
Pilot Scale ◽  
Two Stage ◽  
Green Waste ◽  
Wet Weight ◽  
Two Phases

The composting of green waste (GW) proceeds slowly due to the presence of slowly degradable compounds in that substrate. The introduction of amendments and bulking materials can improve organic matter degradation and end-product quality. However, additional strategies such as two-stage composting, can deal with the slow degradation of green waste. This paper evaluates the effect of two-stage composting on the process and end-product quality of the co-composting of green waste and food waste amended with sawdust and phosphate rock. A pilot-scale study was developed using two treatments (in triplicate each), one being a two-stage composting and the other being a traditional composting. The two treatments used the same mixture (wet weight): 46% green waste, 19% unprocessed food waste, 18% processed food waste, 13% sawdust, and 4% phosphate rock. The traditional composting observed a higher degradation rate of organic matter during the mesophilic and thermophilic phases and observed thermophilic temperatures were maintained for longer periods during these two phases compared to two-stage composting (i.e., six days). Nonetheless, during the cooling and maturation phases, the two treatments had similar behaviors with regard to temperature, pH, and electrical conductivity, and the end-products resulting from both treatments did not statistically differ. Therefore, from this study, it is concluded that other additional complementary strategies must be evaluated to further improve GW composting.

Achieving “Final Storage Quality” of municipal solid waste in pilot scale bioreactor landfills

2009 ◽  
Vol 29 (1) ◽  
pp. 78-85 ◽  
Author(s):  
R. Valencia ◽  
W. van der Zon ◽  
H. Woelders ◽  
H.J. Lubberding ◽  
H.J. Gijzen
Keyword(s):  
Municipal Solid Waste ◽  
Solid Waste ◽  
Pilot Scale ◽  
Bioreactor Landfills ◽  
Storage Quality

Innovative Utilization of a Borate Additive in Magnesium Production to Decrease Environmental Impact of Fluorides from Pidgeon Process

2013 ◽  
Vol 690-693 ◽  
pp. 378-389 ◽  
Author(s):  
Feng Lan Han ◽  
Qi Xing Yang ◽  
Lan Er Wu ◽  
Chun Du
Keyword(s):  
Environmental Impact ◽  
Pilot Scale ◽  
Positive Effects ◽  
Magnesium Production ◽  
First Time ◽  
Pidgeon Process

The present authors have utilized, for the first time, H3BO3as an additive in pilot scale experiments of Mg production using Pidgeon process. The results from the experiments revealed positive effects of H3BO3on both quantity and quality of the Mg metal crowns. Besides acting as a catalyzer for MgO reduction, H3BO3stabilized also β-Ca2SiO4in the Mg slag. Based on these results, H3BO3may be adopted as an innovative additive replacing fluorite in the Mg production, to enhance sustainability and environmental soundness for the Pidgeon process in China.

Storage Life of Refrozen Silver Hake (Merluccius bilinearis) Processed as Fillets am Minced Flesh from Thawed, Stored, Round-Frozen Fish

1977 ◽  
Vol 34 (12) ◽  
pp. 2369-2373 ◽  
Author(s):  
Doris Fraser Hiltz ◽  
D. H. North ◽  
Barbara Smith Lall ◽  
R. A. Keith
Keyword(s):  
Key Words ◽  
Frozen Storage ◽  
Storage Life ◽  
Freeze Thaw ◽  
Acceptable Quality ◽  
Frozen Fish ◽  
Silver Hake ◽  
Merluccius Bilinearis ◽  
Protein Extractability

Refrozen silver hake (Merluccius bilinearis), processed as fillets and minced flesh after thawing of stored round fish that had been frozen within 14 h of capture, underwent rapid deterioration during storage at −18 °C compared with once-frozen control materials from the same lot of fish. The estimated maximum storage life of silver hake refrozen as fillets after 3 and 6 mo storage of the round fish at −25 °C was reduced to about 4.5 and 1 mo, respectively, from 10 mo for once-frozen control fillets. Quality of the refrozen materials immediately after thawing and refreezing was similar to that of the round-frozen fish, except after 6 mo, where some initial deterioration occurred, particularly in minced flesh. Minced flesh was more unstable in frozen storage than fillets. In all once- and twice-frozen materials, formation of dimethylamine occurred concomitantly with decrease in protein extractability. Round-frozen fish underwent no loss in protein extractability during 6 mo storage at −25 °C, but some lipid hydrolysis occurred. These results suggest that the freeze–thaw–refreeze process as applied to silver hake will yield a final product of acceptable quality provided that storage of the round fish does not exceed 3–4 mo and that the refrozen materials are marketed within a month after processing. Key words: silver hake, Merluccius bilinearis, refrozen storage, dimethylamine, minced flesh

scholarly journals Der Wärmehaushalt periglazialer Hochgebirgsböden – Zusammenhänge zwischen Bodentiefe und Frostwechseln (Nördlicher Tian Shan, Kasachstan)

2009 ◽  
Vol 58 (1) ◽  
pp. 70-85
Author(s):  
Henry Munack ◽  
Hilmar Schröder
Keyword(s):  
Ground Temperature ◽  
Temperature Measurements ◽  
High Mountains ◽  
Freeze Thaw ◽  
Periglacial Zone ◽  
Thermal Content ◽  
Tian Shan

Abstract. Ground temperature measurements have been carried out at eleven different sites of the Prokhodnaja valley in the high mountains of the Zailijskij Alatau (Northern Tian Shan, Kazakhstan) between the summers of 2003 and 2004. For this purpose the periglacial zone and adjacent altitudinal zones have been examined between 2,500 and 4,000 m asl with an equidistance of 250 m. The influences of the altitude, the exposure as well as the depth below the earth’s surface on the thermal content and condition of periglacial soils have been considered. The measurements provide useful information about the relations between quantity and quality of freeze-thaw action and the parameters mentioned above.

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