The Effect of Operational Factors on Solid/Liquid Separation by Ultra-Membrane Filtration in a Biological Denitrification System for Collected Human Excreta Treatment Plants

1991 ◽  
Vol 23 (7-9) ◽  
pp. 1583-1590 ◽  
Author(s):  
Y. Magara ◽  
M. Itoh
Keyword(s):  
Membrane Filtration ◽  
Suspended Solids ◽  
Permeation Flux ◽  
Filtration Process ◽  
Liquid Separation ◽  
Human Excreta ◽  
Treatment Processes ◽  
Solids Concentration ◽  
Solid Liquid ◽  
Solid Liquid Separation

One third of the total population of Japan is served by collected human excreta treatment systems for the sanitary treatment of human wastes. In order to cope with the stringent effluent quality regulations set for human excreta treatment plants, the high-load biological denitrification process with ultra-membrane filtration for solid/liquid separation has been recently developed. This system has big advantages not only with respect to the solid/liquid separation stage of biological treatment processes, but also as regards the cost and operational effectiveness of advanced treatment processes such as ozonation and activated carbon adsorption. However, problems can be experienced with the ultra-membrane filtration process because the attainable hydraulic load is completely governed by the permeation flux. Therefore, in order to utilized the ultra-membrane filtration process in a biological wastewater treatment system, the effects of the operational factors on the permeation flux have to be clarified. In this paper, the effects of factors such as water temperature, suspended solids concentration, driving pressure, and water velocity in the unit are described. It has become clear that in order to attain a stable permeation flux, the water temperature and suspended solids concentration should be kept as stable as possible. The results of the investigation of the development of cake or gel layer resistance showed that high pressure and high velocity give a high and stable permeation flux. However, it has also been shown that the optimum operational conditions are high pressure and low velocity, due to the energy costs for operation of the system.

Biological Phosphorus Elimination Combined with Precipitation and Flocculation

1992 ◽  
Vol 25 (4-5) ◽  
pp. 219-224 ◽  
Author(s):  
T. Grünebaum ◽  
E. Dorgeloh
Keyword(s):  
Nutrient Removal ◽  
Suspended Solids ◽  
Chemical Precipitation ◽  
Phosphate Removal ◽  
Limit Values ◽  
Precipitation Treatment ◽  
Solids Concentration ◽  
Solid Liquid ◽  
Solid Liquid Separation ◽  
Biological Phosphorus

As interactions between chemical precipitation and biological wastewater treatment are well known, biological phosphate removal should be considered for advanced nutrient removal. A combination of biological phosphate removal and chemical precipitation treatment is sensible and economic, when the precipitation step is used for removal of residual amounts of phosphate. Improved biological phosphate removal and simultaneous precipitation both give increase in dry solids phosphate content. Assuming a concentration of 0.05 gP/gSS and an effluent suspended solids concentration of 20 mg/l the solids contribution accounts for a Ptot-discharge of 1 mgP/l wastewater. Efficient solid/liquid separation is therefore vital in achieving Ptot-limit values.

Application of Ceramic Membrane Filtration to Remove the Solid in Nisin Fermentation Broth

2008 ◽  
Vol 4 (4) ◽  
Author(s):  
Zhaoliang Wu ◽  
Yuqiang Ji ◽  
Yanan Guo ◽  
Junna Hu
Keyword(s):  
Membrane Filtration ◽  
Ceramic Membrane ◽  
Fermentation Broth ◽  
Experimental Results ◽  
Liquid Separation ◽  
Removal Ratio ◽  
Nisin Fermentation ◽  
Solid Liquid ◽  
Solid Liquid Separation

Solid-liquid separation is an important step for the separation of nisin from the fermentation broth. This paper studied the application of ceramic membrane filtration to remove the solid. Experimental results indicated that the solid removal ratio was above 99% at pH 2.5, 40-50 °C, 0.1 Mpa, recovery of nisin being 84.4%, and while at pH 2.5 HCl was added to dilute the residue in the later stage. Compared to the recovery without the diluted residue, the yield increased 17.4%.

scholarly journals Metal Sulfide Precipitation: Recent Breakthroughs and Future Outlooks

Minerals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 1385
Author(s):  
Humberto Estay ◽  
Lorena Barros ◽  
Elizabeth Troncoso
Keyword(s):  
Membrane Filtration ◽  
Metal Sulfide ◽  
Flow Diagram ◽  
Research Approach ◽  
Liquid Separation ◽  
Direct Production ◽  
Unit Operations ◽  
Sulfide Precipitation ◽  
Solid Liquid ◽  
Solid Liquid Separation

The interest in metal sulfide precipitation has recently increased given its capacity to efficiently recover several metals and metalloids from different aqueous sources, including wastewaters and hydrometallurgical solutions. This article reviews recent studies about metal sulfide precipitation, considering that the most relevant review article on the topic was published in 2010. Thus, our review emphasizes and focuses on the overall process and its main unit operations. This study follows the flow diagram definition, discussing the recent progress in the application of this process on different aqueous matrices to recover/remove diverse metals/metalloids from them, in addition to kinetic reaction and reactor types, different sulfide sources, precipitate behavior, improvements in solid–liquid separation, and future perspectives. The features included in this review are: operational conditions in terms of pH and Eh to perform a selective recovery of different metals contained in an aqueous source, the aggregation/colloidal behavior of precipitates, new materials for controlling sulfide release, and novel solid–liquid separation processes based on membrane filtration. It is therefore relevant that the direct production of nanoparticles (Nps) from this method could potentially become a future research approach with important implications on unit operations, which could possibly expand to several applications.

Nutrient conditions and reactor configuration influence floc size distribution and settling properties

2012 ◽  
Vol 65 (1) ◽  
pp. 156-163 ◽  
Author(s):  
G. A. C. Ehlers ◽  
D. Wagachchi ◽  
S. J. Turner
Keyword(s):  
Size Distribution ◽  
Nutrient Concentrations ◽  
Size Analysis ◽  
Liquid Separation ◽  
Floc Size ◽  
Treatment Processes ◽  
Floc Size Distributions ◽  
Solid Liquid ◽  
Solid Liquid Separation ◽  
Nutrient Conditions

Floc formation and settleability is critical for effective solid–liquid separation in many wastewater treatment processes. This study aimed to investigate the relationship between particle size distribution and nutrient conditions in different bioreactor configurations. Size distribution profiles of flocs that formed in continuous (B1), continuous with clarifier and return sludge (B2) and SBR (B3) reactors were investigated in parallel under identical nutrient conditions. An eight-fold dilution of the influent COD of a synthetic dairy processing wastewater resulted in a ‘feast and famine’ regime that triggered significant effects on the biomass and flocculation characteristics. Floc size analysis of reactor MLSS revealed a shift in floc sizes when reactors were fed with the minimum (famine) COD wastewater feed (0.61 g L−1). Increasing floc size distributions were detected for all reactors during the minimum COD feed although different size patterns were observed for different reactor configurations. These increases corresponded with variations in aggregation and EPS quantities. The SBR yielded comparatively larger flocs when operated under both COD feeds as indicated by d(0.9) values (90% of particles ≤ d in size). Overall the results indicated that floc formation and floc size are mediated by nutrient concentrations and represents an important step towards improved solid–liquid separation.

Investigations on the filtration of natural aquatic suspensions supported by dosing small amounts of Fe(III)-salts (βFe ≤ 0.1 mg.L-1): mode of action and basic design criteria

2002 ◽  
Vol 2 (2) ◽  
pp. 91-98
Author(s):  
R. Winzenbacher ◽  
R. Schick ◽  
H.-H. Stabel ◽  
M. Jekel
Keyword(s):  
Large Scale ◽  
Suspended Solids ◽  
Iron Hydroxides ◽  
Essential Step ◽  
Iron Salts ◽  
Alkaline Earths ◽  
Co Precipitation ◽  
Solid Liquid ◽  
Solid Liquid Separation

Improved removal of particles during the treatment of natural aquatic suspensions has been achieved by pre-ozonation and the addition of small quantities of iron salts (βFe ≤ 0.1 mg.L-1; “Fe(III)-assisted filtration”) followed by rapid filtration. As shown by investigations on a large-scale installation at Lake Constance Water Supply, this procedure reliably reduces suspended solids by at least 2-3 powers of ten in long-term use. However, the high efficacy of Fe(III)-assisted filtration cannot be explained on the basis of known coagulation mechanisms (like adsorption-charge neutralization, co-precipitation). Instead, the essential step was found to be the conditioning of the filter medium by coating it with colloids containing Fe(OH)3, and this “Fe coating” process occurs only in the presence of alkaline earths (especially Ca2+). According to further experiments, the enhanced solid-liquid separation was ultimately traced to chemical interactions such as the formation of calcium-organic association structures between the iron hydroxides and other solids. For design of Fe(III)-assisted filtration steps, finally, a βCa/DOC ratio above 40 mg.mg-1 and pre-oxidation with ozone dosages not exceeding 2 mg O3/mg DOC was recommended.

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