Flocculation

In this work, a brewer’s yeast strain was used to remove heavy metals from a synthetic effluent. The solid–liquid separation process was carried out using the flocculation ability of the strain. The yeast strain was able to sediment in the presence of Cu2+, Ni2+, Zn2+, Cd2+ and Cr3+, which evidences that the flocculation can be used as a cheap and natural separation process for an enlarged range of industrial effluents. For a biomass concentration higher than 0.5 g/l, more than 95% of the cells were settled after 5 min; this fact shows that the auto-aggregation of yeast biomass is a rapid and efficient separation process. Cells inactivated at 45 °C maintain the sedimentation characteristics, while cells inactivated at 80 °C lose partially (40%) the flocculation.The passage of metal-loaded effluent through a series of sequential batches allowed, after the second batch, the reduction of the Ni2+concentration in solution for values below the legal limit of discharge of wastewater in natural waters (2 mg/l); this procedure corresponds to a removal of 91%. A subsequent batch had a marginal effect on Ni2+ removal (96%).Together, the results obtained suggest that the use of brewing flocculent biomass looks a promising alternative in the bioremediation of metal-loaded industrial effluents since the removal of the heavy metals and cell separation are simultaneously achieved.

This paper presents an optimization of a lightweight biopolymer drilling fluid for underbalanced drilling (UBD) using Response Surface Methodology (RSM). Concentrations of four raw materials (glass bubbles, clay, xanthan gum and starch) were varied to analyze their effects on three vital responses: density, plastic viscosity (PV) and yield point (YE') of the fluid. Based on the results, the optimum condition was achieved at concentrations of glass bubbles, clay, xanthan gum and starch of 24.46% w/v,0.63% w/v, 0.21% w/v and 2.41% w/v, respectively. The results showed that it is possible to predict the three response parameters using models generated by RSM since the experimental values were found to be in good agreement with the predicted values (error <1.0, standard deviation < 0.5 and accuracy > 98.5%). (C) 2015 Elsevier B.V. All rights reserved.

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Land spreading of dairy soiled water (DSW) may result in pollution of ground and surface waters. Treatment of DSW through sludge-supernatant separation using chemical coagulants is a potential option to reduce the negative environmental impacts of DSW. The aims of this study were to (1) assess the effectiveness of three chemical coagulants-poly-aluminium chloride (PACl), ferric chloride (FeCl 3) and alum-in improving effluent quality, and (2) assess the properties of the sludge that is generated as by-product from the process for its suitability for land application. Taking into consideration optimum doses to minimize pollutants (turbidity, chemical oxygen demand (COD), total phosphorus (TP), total nitrogen (TN), and E. coli), optimum mixing times and cost, FeCl 3 was the best performing coagulant. Generated sludges had higher nutrient content and fewer E. coli than raw DSW, and did not display any evidence of phytotoxicity to the growth of Lolium perenne L. using germination tests. The study discussed the results in a sustainable farm management context, and suggested that the effluent (supernatant) from the treatments may be recycled to wash farm yards, saving water. In parallel, the sludge portion can be applied to amend soil properties with no adverse impacts on the grass growth, providing an agronomic value as an organic fertilizer, and reducing the risk of nutrient losses. This management approach could minimize the overall net cost compared to land application of raw DSW.

The microbial activity within activated sludge floc is a key factor in the performance of the activated sludge process. In this study, the microenvironment of activated sludge flocs from two wastewater treatment plants (Mill Creek Wastewater Treatment Plant and Muddy Creek Wastewater Treatment Plant, with aeration tank influent CODs of 60-120 and 15-35 mg/L, respectively) were studied by using microelectrodes. Due to microbial oxygen utilization, the aerobic region in the activated sludge floc was limited to the surface layer (0.1-0.2mm) of the sludge aggregate at the Mill Creek plant. The presence of an anoxic zone inside the sludge floc under aerobic conditions was confirmed in this study. When the dissolved oxygen (DO) in the bulk liquid was higher than 4.0mg/L, the anoxic zone inside the activated sludge floc disappeared, which is helpful for biodegradation. At the Muddy Creek plant, with its lower wastewater pollutant concentrations, the redox potential and DO inside the sludge...

Flokulasi adalah tahap pengadukan lambat yang mengikuti unit pengaduk cepat (koagulasi). Tujuan dari proses ini adalah untuk mempercepat laju tumbukan.
Berikut contoh evaluasi perhitungan desain flokulator pada IPA kapasitas 100 lpd di PDAM Tirta Bhagasasi

The use of natural coagulants is a promising alternative to replace or assist chemical coagulants due to its numerous advantages. This paper evaluates the effectiveness of a natural coagulant in water treatment. The coagulant was extracted from the Zygia cauliflora (Willd.) Killip seed in saline solutions and defatted using 95% ethanol. The tests were conducted using different concentrations of the coagulant (0.1, 0.5, 1.0, 2.0, 3.0, and 4.0 g L-1) and of NaCl (0.0 M, 1.0 M, and 5.0 M). The results showed that the use of 2 g L-1 of coagulant and 1.0 M of the salt achieved an effectiveness of 20% and 70%, respectively, of color and turbidity removal. The analysis showed an effectiveness of 70% and 30%, respectively, when removing the UV254 compound and DOM (dissolved organic matter). The mechanism for turbidity removal by the coagulants prepared with aqueous solution and with saline solution at 1.0 M of NaCl is supposed to be adsorption and charge neutralization, respectively, follow...

A large amount of water is used in almost every stage of the mining industry,
especially in mineral processing. Solid-liquid separation methods are applied to
wastewater, which generally consists of fine particles and water; fine particles are settled in
thickeners by flocculation method and the cleaned water is reused in the plants. The
capacity of the thickeners, the amount and clarity of the the recycled water to the plant
depend on the sedimentation rate of the particles/flocs brought together by the flocculation
method. In this respect, it is very important to determine the sedimentation behavior of the
tailings generated in an ore dressing plant by flocculation method.
In this study, flocculation experiments were carried out to determine the optimum
flocculation conditions and setting behavior of copper tailings. In the experimental studies,
the effects of foculant type and dosage, pH, mixing time and speed, solid ratio, flocculation
application method and water used on flocculation were investigated. As a result, turbidity
values lower than the targeted 20 NTU turbidity value were achieved with the other
flocculants except the nonionic flocculant at a dosage of 20 gr/t; For the settling velocity, it
was determined that the settling velocity values greater than 6 m/h were achieved with only
two flocculants (Magnofloc 5250 and SPP 355) at 20 g/t flocculant dosage. The best
flocculation success was obtained with Magnofloc 5250 at 50 gr/t dosage, with the lowest
turbidity value of 1.1 NTU and the highest settling velocity value of 11.49 m/h. At the
same time, with the Magnofloc 5250, the free-settling time of the waste was reduced from
about 11 minutes to 1 minute. With the anionic flocculant (Magnofloc 5250), the lowest
turbidity (1.26 NTU) was found at pH 11.11, and the highest precipitation rate was 10.3
m/h at pH 8.35. The optimum mixing conditions were determined as 200 rpm mixing
speed and 1 minute mixing time. The most suitable solid ratio values in terms of
flocculation performance were found to be 5% and 10% solids. While lower turbidity
values were obtained with the jar tests, higher sedimentation rates were obtained in the
experiments performed on the tape measure. Finally, better flocculation results were
obtained with tap water compared to plant water.
Keywords: Copper tailings, flocculation, precipitation.

Microwave-initiated synthesis of polyacrylamide-grafted sodium alginate, a graft copolymer with wide variety of applications has been reported in this study. The effect of reaction parameters (i.e., irradiation time and monomer concentration) onto the percentage grafting has been investigated. The resulting polymer has been characterized by a variety of characterization techniques such as intrinsic viscosity measurement, Fourier transform infrared spectra, 13C NMR spectra, elemental analysis, thermogravimetric analysis, molecular weight determination using static light scattering analysis, and scanning electron micrographs. Further, the flocculation efficiency of this graft copolymer has been investigated in coal suspension. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010

Concentrated fruit juice industries use a wide volume of water for washing and fruit processing, generating a large volume of wastewater. This work studied the combination of an aerobic biological process with a chemical coagulation/flocculation step to treat a high concentrated fruit juice wastewater. This wastewater presents a good biodegradability (BOD5/COD = 0.66) allowing a chemical oxygen demand (COD) removal above 90% in most reactors. The best results in aerobic biological treatment were obtained in reactors initially loaded with 2 g VSS L−1 of biomass concentration and 20 g COD L−1 of organic matter concentration. Three different kinetic models were evaluated (Monod, Haldane and Contois). The Haldane-inhibition model was the one that best fitted the COD biodegradation. AQUASIM© software allowed calculate the following kinetic constants ranges for aerobic biodegradation: K s: 6–20 g COD L−1; v max: 2.0–5.1 g COD g−1 VSS day−1 and K i values: 0.10–0.50 g COD L−1. These constants corresponds to maximum removal rates (v*) between 0.11 and 0.26 g COD g−1 VSS day−1 for substrate concentrations (S*) from 0.77 to 3.16 g COD L−1. A tertiary coagulation/flocculation process improved the efficiency of the biological pre-treatment. Ferric chloride was selected as best compromise to treat this wastewater. Optimal conditions were 0.44 g L−1 of coagulant at pH = 5.5, achieving 94.4% and 99.6% on turbidity and COD removal, respectively.