Removal of suspended substances by coagulation and foam separation from municipal wastewater

2002 ◽  
Vol 46 (11-12) ◽  
pp. 183-188 ◽  
Author(s):  
Y. Suzuki ◽  
T. Maruyama ◽  
H. Tegane ◽  
T. Goto
Keyword(s):  
Suspended Solids ◽  
Municipal Wastewater ◽  
Treatment Time ◽  
Separation Process ◽  
Foam Separation ◽  
Suspended Substances ◽  
Milk Casein ◽  
Short Time ◽  
Solid Liquid ◽  
Solid Liquid Separation

A new method for solid-liquid separation for wastewater incorporating simple operation and shortened treatment time is necessary for improvement of sewage systems. In this study, removal of suspended solids from municipal wastewater by coagulation and foam separation using coagulant and milk casein was examined. By adding casein before the foam separation process, the removal of suspended substances was dramatically improved. The optimum condition for treating sewage was 20 mg-Fe/L of FeCl3, 3 mg/L of casein, and pH 5.5, which resulted in a removal rates of over 98% for turbidity and SS. A removal of 96-98% was also possible for phosphate and anionic surfactant. When PAC was used, the floc was also efficiently recovered in foam by the addition of casein. It became clear that coagulation and foam separation using casein as the collector is an effective method for removing suspended solids in municipal wastewater in a short time (within 10 min).

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.

scholarly journals Enhancing Bioenergy Yields from Sequential Bioethanol and Biomethane Production by Means of Solid–Liquid Separation of the Substrates

Energies ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3683 ◽  
Author(s):  
Lisandra Rocha-Meneses ◽  
Jorge A Ferreira ◽  
Nemailla Bonturi ◽  
Kaja Orupõld ◽  
Timo Kikas
Keyword(s):  
Flue Gas ◽  
Cost Effective ◽  
Separation Process ◽  
Energy Output ◽  
Bioethanol Production ◽  
Liquid Separation ◽  
Lignocellulosic Feedstock ◽  
Transportation Sector ◽  
Solid Liquid ◽  
Solid Liquid Separation

The production of second-generation ethanol using lignocellulosic feedstock is crucial in order to be able to meet the increasing fuel demands by the transportation sector. However, the technology still needs to overcome several bottlenecks before feasible commercialization can be realized. These include, for example, the development of cost-effective and environmentally friendly pretreatment strategies and valorization of the sidestream that is obtained following ethanol distillation. This work uses two chemical-free pretreatment methods—nitrogen explosive decompression (NED) and synthetic flue gas explosive decompression—to investigate the potential of a bioethanol production sidestream in terms of further anaerobic digestion. For this purpose, samples from different stages of the bioethanol production process (pretreatment, hydrolysis, and fermentation) and the bioethanol sidestream went through a separation process (involving solid–liquid separation), following which a biomethane potential (BMP) assay was carried out. The results show that both factors being studied in this article (involving the pretreatment method and the separation process) served to influence methane yields. Liquid fractions that were obtained during the process with NED gave rise to methane yields that were 8% to 12% higher than when synthetic flue gas was used; fermented and distillation sidestream gave rise to the highest methane yields (0.53 and 0.58 mol CH4/100 g respectively). The methane yields from the liquid fractions were between 60–88% lower than those that were obtained from solid fractions. Samples from the bioethanol sidestream (solid fraction) that were pretreated with NED had the highest methane yield (1.7 mol CH4/100 g). A solid–liquid separation step can be a promising strategy when it comes to improving the energy output from lignocellulosic biomass and the management of the ethanol distillation sidestream.

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.

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.

Study of the Influence of the Underflow Diameter on the Separation Process of an Optimized Hydrocyclone for Concentration Purposes

2017 ◽  
Vol 899 ◽  
pp. 136-141 ◽  
Author(s):  
S.M. Gonçalves ◽  
Yanne Novais Kyriakidis ◽  
Luiz Gustavo Martins Vieira ◽  
Marcos Antonio de Souza Barrozo
Keyword(s):  
Laboratory Experiments ◽  
Differential Evolution Algorithm ◽  
Optimization Procedure ◽  
Separation Process ◽  
Total Efficiency ◽  
Cfd Simulations ◽  
Evolution Algorithm ◽  
Filtration Effect ◽  
Solid Liquid ◽  
Solid Liquid Separation

Hydrocyclones are equipment typically used in solid-liquid separation. Such equipment can be used with the purpose of classifying particles or concentrating suspensions. In this context, a new filtering hydrocyclone was conceived through Surface Response and Differential Evolution Algorithm techniques in order to optimize the Euler’s number. Based on this optimized geometry, the aim of the present paper was to verify the influence of the underflow diameter on the overall separation process at 147 kPa on the same optimized hydrocyclone geometry, but without the filtration effect, by performing laboratory experiments and CFD simulations using the commercial software Fluent®. The results showed that the use of the smallest underflow diameter increased up to 44% (v/v) the concentration of the underflow stream, compared to the suspension initially fed, with an Euler’s number of 862. Despite a small decrease (14%) in the total efficiency and an increase from 12.01 to 16.05 of the reduced cut size diameter, compared to the underflow diameter originally used in the optimization procedure, the benefits of recovering liquid by reducing the underflow diameter outweigh these disadvantages.

Toxic metals removal from dilute solutions by biosorptive flotation

1995 ◽  
Vol 32 (9-10) ◽  
pp. 211-220
Author(s):  
A. I. Zouboulis ◽  
P. Solari ◽  
K. A. Matis ◽  
G. A. Stalidis
Keyword(s):  
Toxic Metal ◽  
Separation Process ◽  
Dissolved Air Flotation ◽  
Metals Removal ◽  
Dilute Aqueous Solutions ◽  
Flotation Technique ◽  
Solid Liquid ◽  
Solid Liquid Separation ◽  
Digested Sewage Sludge ◽  
Dissolved Air

Toxic metal ions (cadmium, nickel and zinc), considered as priority pollutants, were removed from dilute aqueous solutions by sorption onto non-living (sterilized) anaerobically digested sewage sludge. The desorption of cadmium from metal-laden sludge was also examined. Flotation was subsequently applied as an effective solid/liquid separation process. The dissolved-air flotation technique was applied for the generation of fine bubbles and, in parallel, electrokinetic measurements were carried out. Promising results were succeeded from the combined process of biosorption/flotation (termed biosorptive flotation).

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