Plywood Mill Water System Closure by Dissolved Air Flotation Treatment

1999 ◽  
Vol 40 (11-12) ◽  
pp. 33-41 ◽  
Author(s):  
P. Jokela ◽  
P. Keskitalo
Keyword(s):  
Heat Recovery ◽  
Occupational Safety ◽  
Suspended Solids ◽  
Water System ◽  
Raw Material ◽  
Surface Load ◽  
Dissolved Air Flotation ◽  
Treated Water ◽  
Air Flotation ◽  
Dissolved Air

In plywood industry water is mainly needed for soaking the logs. Dissolved air flotation with chemical precipitation was found to be a suitable treatment method for the soaking basin overflow of a plywood mill using birch as raw material. According to pilot treatment studies over 90% reductions of the suspended solids are possible with a hydraulic surface load of 6.5 m3/(m2h). In subsequent experience in full scale following reductions have been achieved: suspended solids 93%, BOD7 50%, CODCr 57%, P 92% and N 52%. Two-thirds of the flotation treated water is led to flue gas scrubbers and circulated back to the soaking basin. Optionally water can be led to the heat recovery, too. One-third of the flotation treated water is disposed of as the mill effluent. Concentrations of organic matter in the system have been reduced after the addition of flotation indicating the possibility of further closure. However, due to the use of aluminium sulphate in coagulation, aeration is needed for sulphate reduction prevention. Further closure of the water system is possible in the future if the heat recovery is renovated, preventing the increase of the water temperature (now 37°C) which otherwise might cause occupational safety hazards.

Oil Removal from Refinery Wastes by Air Flotation

1974 ◽  
Vol 9 (1) ◽  
pp. 328-339 ◽  
Author(s):  
B. Volesky ◽  
S. Agathos
Keyword(s):  
Suspended Solids ◽  
Suspended Solid ◽  
Oil Removal ◽  
Dissolved Air Flotation ◽  
Physical Separation ◽  
Sedimentation Technique ◽  
Flocculation Aid ◽  
Flotation Technique ◽  
Air Flotation ◽  
Dissolved Air

Abstract Air flotation as a physical separation process for removing oily products and suspended solid matter from refinery wastewaters achieves removal efficiencies from 65% to more than 90%. Demonstrated capacity of the process for COD and BOD removal ranges up to 90%. With addition of flotation and flocculation aid chemicals better performance is achieved. Current results are presented and critically reviewed. It appears that the pressure dissolved-air flotation system employing recycle-flow operation can produce effluent containing consistently less than 15 p.p.m. of oil and suspended solids. Its performance and capacity of handling overload situations makes it superior to the conventional flocculation-sedimentation technique. Oil removal limitations of the process and current research trends are stressed including an electro-flotation technique. Some aspects of process optimization are also discussed.

A bioflocculant-supported dissolved air flotation system for the removal of suspended solids, lipids and protein matter from poultry slaughterhouse wastewater

2018 ◽  
Vol 78 (2) ◽  
pp. 452-458 ◽  
Author(s):  
C. Dlangamandla ◽  
S. K. O. Ntwampe ◽  
M. Basitere
Keyword(s):  
Steady State ◽  
Suspended Solids ◽  
Total Suspended Solids ◽  
Bacillus Sp ◽  
Dissolved Air Flotation ◽  
Slaughterhouse Wastewater ◽  
Air Flotation ◽  
Dissolved Air

Abstract In this study, two previously identified isolates, i.e. Comamonas aquatica (BF-3) and Bacillus sp. BF-2, were determined to be suitable candidates to utilise in a bioflocculant-supported dissolved air flotation (Bio-DAF) system as a pretreatment system for poultry slaughterhouse wastewater (PSW). A 2% (v/v) (bioflocculant:PSW) strategy was used for the DAF to reduce total suspended solids (TSS), lipids and proteins in the PSW, by supplementing the bioflocculants produced and the co-culture (C. aquatica BF-3 and Bacillus sp. BF-2) directly into the DAF. The Bio-DAF was able to reduce 91% TSS, 79% proteins and 93% lipids when the DAF system was operating at steady state, in comparison with a chemical DAF operated using 2% (v/v) alum that was able to only reduce 84% TSS, 71% proteins and 92% lipids. It was concluded that the Bio-DAF system worked efficiently for the removal of suspended solids, lipids and proteins, achieving better results than when alum was used.

scholarly journals KOMBINASI ULTRAFILTRASI DAN DISSOLVED AIR FLOTATION UNTUK PEMEKATAN MIKROALGA

REAKTOR ◽  
2014 ◽  
Vol 15 (1) ◽  
pp. 43
Author(s):  
I Nyoman Widiasa ◽  
A A Susanto ◽  
B Budiyono
Keyword(s):  
Organic Fertilizer ◽  
Saturation Pressure ◽  
Raw Material ◽  
Natural Food ◽  
Omega 3 ◽  
Dissolved Air Flotation ◽  
Microalgae Biomass ◽  
Air Flotation ◽  
Β Carotene ◽  
Dissolved Air

Abstrak Mikroalga merupakan mikroorganisme fotosintetik prokariotik atau eukariotik yang dapat tumbuh dengan cepat. Pemanfaatan mikroalga tidak hanya berorientasi sebagai pakan alami untuk akuakultur, tetapi terus berkembang untuk bahan baku produksi pakan ternak, pigmen warna, bahan farmasi (β-carotene, antibiotik, asam lemak omega-3), bahan kosmetik, pupuk organik, dan biofuel (biodiesel, bioetanol, biogas, dan biohidrogen. Studi ini bertujuan untuk menginvestigasi kombinasi ultrafiltrasi (UF) – dissolved air flotation (DAF) untuk pemekatan mikroalga skala laboratorium. Hasil penelitian menunjukkan bahwa penurunan fluks membran UF secara tajam sebagai akibat dari deposisi sel mikroalga terjadi pada 20 menit pertama proses filtrasi. Backwash pada interval 20 menit selama 10 detik dengan tekanan 1 bar memberikan pengendalian fouling yang efektif dalam nilai kestabilan fluks yang layak. Membran UF yang digunakan dapat memberikan selektivitas pemisahan biomassa mikroalga ~ 100%. Kualitas permeat sangat stabil, yaitu kekeruhan < 0,5 NTU, kandungan organik < 10 mg/L, dan warna < 10 PCU. Lebih lanjut, pemekatan retentat membran dengan DAF pada tekanan saturasi 6 bar dapat menghasilkan pasta mikroalga dengan konsentrasi 20 g/L. Koagulan PAC perlu ditambahkan kedalam umpan DAF dengan dosis 1,3–1,6 mg PAC/mg padatan tersuspensi.   Kata Kunci: ultrafiltrasi; dissolved air flotation; pemanenan mikroalga; pemekatan mikroalga   Abstract COMBINATION OF Ultrafiltration and Dissolved Air Flotation for Microalgae CONCENTRATION. Microalgae is a prokaryotic photosynthetic microorganism or eukaryotic microorganism  that proliferate rapidly. Cultivation of the microalgae is not only oriented  as natural food for aquacultures, but also developed  for animal food, color pigment, pharmaceutical raw material (β-carotene, antibiotic, fatty acid omega-3), cosmetic raw material, organic fertilizer, and biofuels (biodiesel, bioethanol, biogas, and biohydrogen. This study is aimed to investigate the potential of combination of ultrafiltration (UF) and dissolved air flotation  (DAF) for concentration of microalgae in laboratory scale. The experimental results showed that fluxes of the UF membrane decreased sharply due to deposition of microalgae biomass during first 20 minutes of filtration. Periodically backwash using the UF permeate (backwash  interval = 20 minutes;  backwash duration = 10 seconds;  backwash pressure = 1 bar) gave an effective fouling control to maintain reasonable stable fluxes. In addition,  the UF membrane gave separation of microalgae biomass ~ 100%. Permeate quality is strongly stable in which turbidity < 0.5 NTU, organic content < 10 mg/L, and color < 10 PCU.  Moreover, concentration of the UF retentate by DAF under saturation pressure of 6 bars was able to produced microalgae feedstock having 20 g/L dry microalgae. PAC is required for DAF feed with dosage of 1.3–1.6 mg PAC/mg suspended solids.

Dissolved air flotation clarification of activated sludge and wastewaters from chemical industry

2003 ◽  
Vol 47 (1) ◽  
pp. 205-210 ◽  
Author(s):  
P. Jokela ◽  
J. Immonen
Keyword(s):  
Activated Sludge ◽  
Suspended Solids ◽  
Animal Feed ◽  
Paper Industry ◽  
Dissolved Air Flotation ◽  
Jar Test ◽  
Air Flotation ◽  
Carry Over ◽  
Winter Time ◽  
Dissolved Air

Wastewaters from separate chemical factories are treated together in an extended aeration activated sludge plant. The factories produce chemicals for paper industry (e.g. starch), latexes and animal feed. The components of the wastewaters include styrene, tertiary butanol and vinyl acetate. Activated sludge is clarified by sedimentation. During winter time, when the water temperature was 3-12°C, the clarification deteriorated causing carry over of suspended solids containing COD. Enhancement of suspended solids and COD removals was studied in a dissolved air flotation jar test unit. Flotation trials were conducted for activated sludge, sedimentation treated final effluent (tertiary treatment) and separate wastewater fractions. The need for chemicals, flocculation and amount of recycle water were judged according to the achieved removals. Dissolved air flotation was found well suited for the clarification of activated sludge, but not technically and economically feasible for the clarification of the wastewater streams before the activated sludge treatment.

Optimization of Fenton's reagent coupled to Dissolved Air Flotation to remove cyanobacterial odorous metabolites and suspended solids from raw surface water

2011 ◽  
Vol 64 (8) ◽  
pp. 1668-1674 ◽  
Author(s):  
Jorge A. Elías-Maxil ◽  
Fotis Rigas ◽  
María Teresa Orta de Velásquez ◽  
Rosa-María Ramírez-Zamora
Keyword(s):  
Water Treatment ◽  
Suspended Solids ◽  
Advanced Oxidation Process ◽  
Treatment Plant ◽  
Drinking Water Treatment ◽  
Fenton’S Reagent ◽  
Fenton's Reagent ◽  
Dissolved Air Flotation ◽  
Air Flotation ◽  
Dissolved Air

Ferrous salts are commonly used as coagulants in Water Treatment Plants (WTPs). When these salts are combined with hydrogen peroxide in acidic conditions – besides coagulation – an additional Advanced Oxidation Process (Fenton's reagent) can take place. Using a response surface methodology, this paper presents the optimization of a novel treatment system constituted by Fenton's reagent (FE) and Dissolved Air Flotation (DAF) for removing 2-Methylisoborneol (MIB), geosmin and Total Suspended Solids (TSS) from raw water. FE was proven able to remove completely both micro pollutants found in the influent of a drinking water treatment plant. Moreover, higher clarification rate was achieved by coupling FE-DAF with respect FE-Sedimentation.

Removal of hydrocarbons from petrochemical wastewater by dissolved air flotation

2001 ◽  
Vol 43 (8) ◽  
pp. 107-113 ◽  
Author(s):  
N. I. Galil ◽  
D. Wolf
Keyword(s):  
Organic Matter ◽  
Biological Treatment ◽  
Suspended Solids ◽  
Cationic Polyelectrolyte ◽  
Free Form ◽  
Dissolved Air Flotation ◽  
Separation Unit ◽  
Hydrophobic Compounds ◽  
Air Flotation ◽  
Dissolved Air

The dissolved air flotation (DAF) method has an important role in the removal of hydrocarbons, as well as in the protection of the biological treatment, which usually follows the DAF. The aims of this study were to evaluate the removal efficiencies of suspended solids, general organic matter, hydrocarbons and phenols by DAF, as influenced by the flocculant type, aluminum sulfate (alum) or a cationic polyelectrolyte. Laboratory batch experiments included chemical flocculation followed by DAF, controlling the flocculant dose and the air to solids ratio. The characterization of the influent and effluent was based on general analysis of organic matter (COD), suspended solids, hydrocarbons and phenols. The influent to all experiments was supplied daily from the outlet of a full scale oil-water gravitational separation unit at a petrochemical complex in Haifa, Israel. The influent contained hydrocarbons in the range of 20 to 77 mg/L. Usually less than 10% were found in “free” form, 70 to 80% were emulsified and 10 to 20% were dissolved. The DAF process enabled us to reduce the general hydrocarbon content by 50 to 90%. The effluent was characterized by stable and uniform levels of suspended solids, and oil, almost without depending on the influent concentrations. The results indicate that the chemical flocculation followed by DAF removed efficiently the emulsified phase, which could be aggregated and separated to the surface. However, it was found that the process could also remove substantial amounts of dissolved organic matter. This mechanism could be explained by the hydrophobic characteristics of some of the substances, which could bind to the solid surfaces. It was found that aggregates created by the flocculation with the cationic polyelectrolite (C-577) could remove up to 40% from the dissolved hydrocarbon. Alum flocs also indicated removal of soluble materials, mainly phenols. The results obtained in this study indicated the possibility to improve the protection of the biological treatment process by preliminary removal of hydrophobic compounds, usually considered as either inhibitory or toxic. This removal can be based on sorption onto aggregates created by chemical flocculation, which can be efficiently removed by dissolved air flotation.

scholarly journals Dissolved air flotation (DAF) for biomass recovery from algal ponds

2017 ◽  
Vol 12 (3) ◽  
pp. 534-540 ◽  
Author(s):  
Dayana Melo Torres ◽  
André Luís Calado Araújo ◽  
Rui de Oliveira ◽  
André Câmara de Brito
Keyword(s):  
Suspended Solids ◽  
Sewage Treatment ◽  
Random Factor ◽  
Dissolved Air Flotation ◽  
Sample Characteristics ◽  
Biomass Recovery ◽  
Air Flotation ◽  
Final Effluent ◽  
Flocculation Time ◽  
Dissolved Air

This work evaluated the performance of a dissolved air flotation (DAF) system for biomass recovery from the effluent of algal ponds used for sewage treatment in Northeast Brazil. Two different coagulants and effluent samples were tested following a random-factor experimental design (34–1–4 factors and 3 levels), in triplicate. Factor analysis showed that coagulant dose was the most important factor, independently of the type of coagulant and sample characteristics. For polyaluminium chloride it is possible to work with the original sample pH at the lower recirculation rate (10%) and flocculation time (10 minutes), being able to recovery an algal masses (dry basis) of around 1,200 kg/day and 550 kg/day from the primary facultative and second maturation pond (final effluent), respectively. DAF was more efficient for ferric chloride, however a pH correction to the value of 5.0 was necessary, leading the process to generate masses of solids (dry basis) of about 1,150 kg/day for the facultative pond and 830 kg/day for the maturation pond. Removals of suspended solids, turbidity, and chlorophyll-a were above 60%, reaching at optimal conditions removals up to 90%.

Application of Chitosan in Removing Algae by Dissolved Air Flotation

2011 ◽  
Vol 347-353 ◽  
pp. 1911-1916 ◽  
Author(s):  
Yu Heng Wang ◽  
Sheng Guang Zhuo ◽  
Yi Xin Yang ◽  
Na Li
Keyword(s):  
Aluminum Concentration ◽  
Removal Rates ◽  
Dissolved Air Flotation ◽  
Treated Water ◽  
Residual Aluminum ◽  
Flotation Performance ◽  
Air Flotation ◽  
Polyaluminium Chloride ◽  
Dissolved Air

Using polyaluminium chloride (PAC) and chitosan as the main coagulant and coagulant-aid respectively, the high algae-laden water was treated by coagulation/flocculation/dissolved air flotation (C/F/DAF). When the doses of PAC and chitosan were both moderate (7.0~8.4 mg Al2O3/L of PAC and 0.6~1.0 mg/L of chitosan), the removal rates of turbidity, algae cells and TOC were all increased apparently compared with adding PAC alone. Especially, the residual aluminum concentration reduced significantly in treated water with the aid of chitosan. The structrue and strength of flocs formed by coagulation aid of chitosan were improved obviously, which proved that addition of chitosan could enhance the flocculation performance of PAC. So, in C/F/DAF process for removing algae, using chitosan as coagulant-aid can improve the flotation performance and reduce residual aluminum concentration in treated water.

Flow structures in a dissolved air flotation pilot tank and the influence on the separation of MBBR floc

2002 ◽  
Vol 2 (2) ◽  
pp. 69-76 ◽  
Author(s):  
M. Lundh ◽  
L. Jönsson ◽  
J. Dahlquist
Keyword(s):  
Flow Structure ◽  
Removal Efficiency ◽  
Pilot Plant ◽  
Suspended Solids ◽  
Short Circuit ◽  
Flow Structures ◽  
Dissolved Air Flotation ◽  
Air Content ◽  
Air Flotation ◽  
Dissolved Air

The objective of the study was to find ways of improvement of the dissolved air flotation process by studying the flow structure. The paper presents experimental data on flow structures and the relation between the flow structure and the removal efficiency. Measurements have been performed in a pilot plant with an Acoustical Doppler Velocimeter. The water velocity was measured in a grid net, giving insight into the flow structure. The removal efficiency was analysed at Malmö wastewater treatment plant in Sweden. The pilot plant separated biological floc from a Kaldnes Moving Bio-Bed Reactor (MBBR). The efficiency of the separation was analysed by measurements of suspended solids in the influent and the effluent. Air content was measured inside the tank and in the re-cycle. The result showed that basically two flow structures existed; the stratified and the short-circuit flow structure. The stratified flow structure seemed correlated to efficient separation of particles while the short-circuit flow structure seemed to have a negative effect, especially when the flow structure was affected by varying the re-cycle rate, i.e. the air content. Conclusively, the flow structure seemed to be correlated to type of flow structure. However, studies with higher concentration of suspended solids for verification were suggested.

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