The separation characteristic of falling film type of freeze concentration equipment Waste water curtailment and recycling of water using ice thermal storage

Experiments with a falling film reactor were conducted to examine the potential of the freeze concentration to reuse municipal waste water. The waste water was recycled in the falling film reactor while ice films were frozen on the cooled inner walls. Pure water was removed from the solution by crystallization, and the liquor was concentrated. Finally, the separated clear ice was melted. Various parameters such as conduction, TOC, COD and NH4-N of the melted ice and waste water concentrate were measured. A clearance efficiency up to 99% was observed for municipal waste water and 91% for high concentrated waste water. In addition, particulate solutions were removed from the aqueous phase as efficiently as the organic and inorganic solutes.

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Heat Transfer Characteristics through the Vertical Falling Liquid Film on a Spirally Wound Fir-Finned Tube Used for a Falling-Film Type Absorber

KAGAKU KOGAKU RONBUNSHU ◽

10.1252/kakoronbunshu.32.262 ◽

2006 ◽

Vol 32 (3) ◽

pp. 262-268 ◽

Cited By ~ 1

Author(s):

Kazushige Nakao ◽

Eiichi Ozaki ◽

Tsuneo Yumikura ◽

Masaki Ikeuchi ◽

Goro Yamanaka ◽

...

Keyword(s):

Heat Transfer ◽

Liquid Film ◽

Finned Tube ◽

Falling Film ◽

Heat Transfer Characteristics ◽

Transfer Characteristics ◽

Falling Liquid Film ◽

Film Type

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Freeze concentration for enrichment of nutrients in yellow water from no-mix toilets

Water Science & Technology ◽

10.2166/wst.2004.0360 ◽

2004 ◽

Vol 50 (6) ◽

pp. 61-68 ◽

Cited By ~ 12

Author(s):

H. Gulyas ◽

P. Bruhn ◽

M. Furmanska ◽

K. Hartrampf ◽

K. Kot ◽

...

Keyword(s):

Energy Consumption ◽

Falling Film ◽

Mechanical Agitation ◽

Stirred Vessel ◽

Multistage Processes ◽

Freeze Concentration ◽

Ecological Sanitation ◽

Water Transportation ◽

Third Stage ◽

Water Constituents

Separately collected urine (“yellow water”) can be utilized as fertilizer. In order to decrease storage volumes and energy consumption for yellow water transport to fields, enrichment of nutrients in yellow water has to be considered. Laboratory-scale batch freeze concentration of yellow water has been tested in ice-front freezing apparatus: a stirred vessel and a falling film freeze concentrator (coolant temperatures: -6 to -16°C). With progressing enrichment of the liquid concentrate, the frozen ice was increasingly contaminated with yellow water constituents (ammonia, total nitrogen, total phosphorus, TOC, and salts determined as conductivity). The higher the initial salinity of the yellow water and the lower the mechanical agitation of the liquid phase contacting the growing ice front, the more the frozen ice was contaminated. The results indicate, that in ice-front freezing devices multistage processes are necessary, i.e. the melted ice phase has to be purified (and the concentrates must be further enriched) in a second or even in a third stage. Energy consumption of this process is very high. However, technical scale suspension freeze concentration is reasonable in centralized ecological sanitation schemes if the population exceeds 0.5 million and distance of yellow water transportation to fields is more than 80 km.

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