Optimum conditions to treat high-concentration microparticle slime water with bioflocculants

We studied how bioflocculants,produced by white-rot fungi,affect flocculation in slime water.Based on a test in an orthogonal design,flocculation conditions were optimized.The results show that flocculation activity is at its highest when the following conditions are met:slime water concentration 27.42 g/L;coagulant aid(CaCl_2) mass concentration 5.0 g/L;two-segment stirrings:the first at a stirring speed of 60 r/min for 180 s and the second 180 r/min for 60 s;a pH of 11 and a flocculant concentration of 15 mL/L.The flocculation activity can be up to 98.71%of bioflocculants at the time.Further experiments indicate that most of the flocculation active material is found outside the mycelium cells.This is the extracellular secretion produced by mycelium cells during the fermentation process.This flocculant has strong thermal stability.Many kinds of cations have a flocculation function to assist bioflocculants.This aid-flocculation effect of the divalent cation Ca^(2+) is obvious in the bioflocculant produced by the white-rot fungus.Therefore,this is of great value when applied to control engineering in the battle against water pollution.

Application of organic polymeric flocculants in centrifugal dewa-tering of oil refinery sludge

In order to evaluate the applicability of the organic polymeric flocculants(OPF) in the treatment of oil refinery sludge, experiments were conducted to show that OPF have better performance of flocculation than inorganic flocculants. Both the anionic and cationic OPF have satisfactory flocculation efficiency in oil sludge treatment, but the latter are more cost efficient. Among the over 20 types of flocculants tested, 2 OPF(CPAM 2 and HPAM 2) were selected as the treatment agents, based on their good treatment performances, oil resistance and economic feasibility. It was demonstrated in the industrial scale centrifugal dewatering experiments that the application of either CPAM 2 or HPAM 2 could achieve high treatment efficiency of the oil sludge dewatering and reduce the COD of centrifugal liquid to less than 1000 mg/L.

DMC-grafted cellulose as green-based flocculants for agglomerating fine kaolin particles

Novel cellulose based flocculants C-g-P(DMC) with various chain architectures are synthesized through a situ graft copolymerization. The cationic ammonium chloride group(DMC) is grafted onto cellulose by two separate inverse emulsion polymerization with γ-methacryloxypropyl trimethoxy silane(KH-570) and double bond addition reactions, which is a new and simple method to employ KH-570 as a bridge for the connection of cellulose matrix and DMC group. The effects of pH, flocculant dose, standing time on turbidity of kaolin suspensions and particle sizes have been studied systematically. In addition, the response surface methodology(RSM) study confirms that PAC and C-g-P(DMC)have synergy in turbidity removal with a higher removal efficiency of 98.32%. Moreover, C-g-P(DMC) 1 has higher removal efficiency with 96.5% at a low dosage of 0.6 mg L^(-1) and better floc properties than C-g-P(DMC) 2 and C-g-P(DMC) 3, suggesting that the length and quantity of cationic branch chains play a crucial role in Kaolin flocculation due to their dramatically enhanced bridging effects.

Screening of Bioflocculant-Producing Strain by Ion Implantation and Flocculating Characteristics of Bioflocculants

A bioflocculant-producing mutator strain, NIM-192, was screened out through nitrogen ion implanting into F J-7 strain. The results showed that NIM-192 had good genetic stability and high flocculating activity, and the flocculating rate increased by 34.26% than that of the original. Sucrose, complex nitrogen source contained yeast extract, urea and pH 7.0～ 9.0 were chosen as the best carbon source, nitrogen source and initial solution pH for bioflocculant production, respectively. The bioflocculant kept high and stable flocculating activity at alkalinous reaction mixture with a pH beyond 7.0, while the flocculating activity was remarkably reduced when the reaction pH was lower than 7.0. Addition of many cations could obviously increase the flocculating rate, among which Ca^2＋ demonstrated the best effect. The bioflocculant had very strong acid-base stability and thermo-stability.The flocculating rate kept over 86% when pH of the bioflocculant was in a range of 3.0 ～ 12.0, and the change of flocculating activity was not great when heated at 100℃ for 60 rain.

Comparison of three flocculants for heavy cyanobacterial bloom mitigation and subsequent environmental impact

Cyanobacteria can accumulate as a heavy biomass on the leeward side of large eutrophic lakes,posing a potential threat to public health.The mitigating capacity of three flocculants and their potential impacts on the major environmental features of water and sediments was evaluated.Results indicate that polyaluminum chloride(PAC)and ferric chloride(FeCl)are efficient flocculants that can rapidly mitigate cyanobacterial blooms with chlorophyll-a concentrations higher tnan 1500 ug/L within 15 min.In comparison,cationic starch with chitosan could only treat cyanobacterial blooms in chlorophyll-a concentrations of less than 200μg/L.The addition of FeClcaused a decline in the pH value,while dissolved oxygen in the water column dropped to 2 mg/L during cationic starch with chitosan treatment for a high cyanobacterial biomass group.Thus,a combination of flocculants and oxygenators should be considered when treating high-concentration cyanobacterial blooms for emergency purposes.Additionally,the cell lysis of cyanobacteria caused by cationic starch with chitosan can result in an increase in total dissolved phosphorus and total dissolved nitrogen.Furthermore,the high accumlation of nutrients in sediments after the settling of cyanobacteria can cause high internal phosphorus pollution.The increase in the total organic carbon of the sediments can threaten lake restoration achieved by planting submerged macrophytes.

Non-parallelism between the effect of microbial flocculants on sewerage disposal and the flocculation rate

This paper dealt with non-parallelism between the effect of microbial flocculant (MBF) on sewerage disposal and the flocculation rate, the high flocculation rate doesn’t mean the fine disposal effectiveness, and revealed the problem encountered when the exclusive parameter―flocculation rate is used to evaluate the effect of MBF on sewerage disposal. The results showed that MBF made from different carbon sources have some influence on the effectiveness of sewerage disposal; flocculation rate cannot authentically reflect the status of sewerage disposal. When the exclusive parameter―flocculation rate is used to evaluate the effect of MBF on sewerage disposal, it would be exaggerated, especially in disposing COD-low sewerage. The authors considered that when flocculation rate is used to evaluate the effect of MBF on sewerage disposal, it is better to take COD-removal rate into account.

Phosphate Sorption in Water by Several Cationic Polymer Flocculants

Although inorganic phosphate is an essential plant nutrient, elevated levels in surface waters lead to adverse effects in the environment. These effects are attributed to runoff from rain or irrigation events that may cause the sorbed phosphate to be transported from the application sites and to move into neighboring watersheds. Increased phosphate concentration in watersheds may lead to a variety of environmental problems including increased algal blooms, bacterial contamination, and in some cases eutrophication. To overcome these effects, polymer flocculants have been shown to reduce the phosphate concentration in water by removing suspended solids and thereby removing the phosphate sorbed to the solids. The purpose of this study is to determine the amount, if any, of phosphate removed by several commercial polymers. The polymers chosen include the polyacrylamides Magnifloc 494C, Magnifloc 985N and Poly (diallyldimethyl ammonium chloride) (Poly (DADMAC)). Using these polymers, it is discovered that the positive charge density of the polymers affects the amount of phosphate removed from solution with Poly (DADMAC) (having 100% positive charge density) removing 40% of the phosphate from a solution containing 10 ppm phosphate.

A critical review on flocculants and flocculation

The article critically reviews the applications of biopolymers in the area of water treatment. A number of biopolymers were reported for their flocculation behavior for treating the wastewater and making it suitable for various industrial as well as agricultural purposes via chemical alteration onto its backbone. Wastewater treatment was followed by flocculation process using standard ‘Jar test protocol’. Minute quantities of dosage were found be ideal to diminish the organic, biological and suspended loads from wastewater sample. The process of flocculation using biopolymers was also found economically suitable compared to other various processes applied in water treatment.

Challenges in developing polymer flocculants to improve bitumen quality in non.aqueous extraction processes:an experimental study

Western Canada’s oil sands hold the third-largest hydrocarbon deposits in the world.Bitumen,a very heavy petroleum,is currently recovered by surface mining with warm water or in situ.Recovery processes that use organic solvents are being developed to reduce water usage and tailings production.While solvent-based methods can effectively extract bitumen,removal of residual fine solids from diluted bitumen product(DBP)to meet the pipeline transport requirement of<0.5 wt%solids and water in DBP remains a major challenge.We propose a novel area of application of polymer flocculants for fine solids removal from DBP.In principle,polymer flocculants can be applied to help remove these residual solids in conjunction with physical separation processes to increase process effectiveness and energy efficiency.Several polymers are selected and screened for flocculation behavior using kaolinite suspended in DBP and toluene,as a model system.Focused beam reflectance measurements and force tensiometer techniques are used to determine flocculation and sedimentation in DBP.The observed flocculation and sedimentation rate enhancements indicate that the polymers tested have only minor effects,providing opportunities for advanced polymer development.These findings exemplify the challenges in identifying polymers that may be effective as flocculants in heavy petroleum media.

Effects of Polymeric Flocculants on Settlement of Bayer Red Mud Generated from Chinese Diaspore Bauxite

A systematic investigation on the interaction between Bayer red mud particles generated from Chinese diaspore bauxite and commercial sodium polyacrylate(SPA) or polyacrylamide(PAM) was performed by red mud settling tests,conductivity-pH titration and Ubbelodhe viscosimetric measurement.The results indicate that the treatment with red mud by SPA gives a lower red mud settling rate and lower supernatant turbidity than the treatment with red mud by PAM.There is an optimum polymer dosage of 300 g/t(based on the weight of dry red mud) when red mud slurry is treated by SPA or PAM,so 'bridging' adsorption is one of the main interactions between red mud and SPA or PAM.With the increase of NaOH concentration,the hydrolysis degree of PAM dissolved in NaOH solution increases and its molecular weight almost does not change,but the settling rate of red mud treated by it drops rapidly.The settling rate of red mud treated by PAM dissolved in 10 g/L NaOH solution is 0.61 m/h while by PAM dissolved in distilled water it is 1.31 m/h,because the adsorption ability of the hydrolyzed PAM onto red mud surface declines primarily due to the formation of-CONH2～-COO-～-CONH2 intramolecular hydrogen bond。

Flocculation performance and mechanism of hydroxamate flocculants on synthetic hematite or goethite suspension

Suitable amounts of Al(OH)3, Na OH and synthetic hematite or goethite were taken to be digested under the simulated condition of the Bayer process and subsequently diluted with simulative Bayer red mud lotion, then the synthetic hematite or goethite suspension was obtained. The flocculation effect of self-made modified poly(acrylic acids) flocculants containing hydroxamic acid groups(abbreviated as HPAA) on the synthetic hematite or goethite suspension was studied. The experimental results show that with the increase of the dosages of added flocculants, the average settling rate of the synthetic hematite or goethite suspension in the first 1min speeds up, the supernatant solids decrease. It could also be found that there is generally a decrease in the average settling rate of the synthetic hematite or goethite suspension in the first 1 min with increasing solid content of the suspension. When the solid content of hematite or goethite of the suspension is 50 g/L with 240 g/t dosage of HPAA, HPAA has a better flocculation effect on the synthetic goethite suspension than on the synthetic hematite suspension. The adsorption mechanism of HPAA on the surface of hematite or goethite was investigated by Fourier transform infrared spectroscopy(FT-IR) and X-ray photoelectron spectroscopy(XPS).All the results suggest that HPAA is adsorbed on the hematite or goethite surface by a chemisorption, and it has a stronger adsorption on the goethite surface than on the hematite surface.

OKRA (HIBISCUS ESCULENTUS) AND FENUGREEK (TRIGONELLA FOENUM GRACEUM) MUCILAGE:CHARACTERIZATION AND APPLICATION AS FLOCCULANTS FOR TEXTILE EFFLUENT TREATMENTS

The use of new food grade polysaccharides (mucilage) obtained from Hibiscus esculentus and Trigonella foenum graceum,commonly called Okra and Fenugreek,respectively,as flocculants was described.These polysaccharides were used for removal of solids (suspended solids (SS) and total dissolved solids (TDS)) and dyes from real textile effluents and aqueous solutions of different class of synthetic dyes.Influences of varying polysaccharide concentration,contact time and pH on removal of pollutant from the textile...

Addition of Thiourea Host Monomer to Polymer Flocculants to Improve Selectivity of Phosphate Sorption

Inorganic phosphate is a common nutrient that is applied as a fertilizer to both agricultural fields as well as urban settings such as private yards, public parks and other urban landscaping. While phosphate typically binds tightly to soil, movement of phosphate off of application sites can occur through soil erosion. The soil and its bound phosphate can then end up in surface waters such as rivers and lakes. Phosphate found in surface water bodies exists both as bound to the suspended clay as well as that free in solution. Elevated phosphate concentration in surface waters can lead to algal blooms and eutrophication. While the phosphate bound to clay in suspension in surface water bodies can be removed by commercially available polymer flocculants, the phosphate that is free in solution is more challenging as it is usually found in low concentrations and other anionic salts are generally present in higher concentrations. To remove phosphate from contaminated water systems, where other anions exist at higher concentrations, it is favorable to have a method of removal that is selective for phosphate. As a proof of principle, thiourea derivatized polymer flocculants were examined for the selective removal of phosphate in the presence of competing anions. The polymer flocculants exhibited selectivity for phosphate through hydrogen bonding and were effective at removing up to 43% of phosphate from simulated wastewater. Computational studies and 1H NMR were used to investigate the selectivity of the thiourea monomer for phosphate over competing anions such as chloride and sulfate.

Ammonium Metavanadate Fabricated by Selective Precipitation of Impurity Chemicals on Inorganic Flocculants

High purity ammonium metavanadate(NH_(4)VO_(3))is the most vital chemical to produce V2O5,VO2,VN alloy,VFe alloy and VOSO4,which have some prospective applications for high strength steel,smart window,infrared detector and imaging,large scale energy storage system.NH_(4)VO_(3)is usually produced by spontaneous crystallization from the aqueous solution due to its sharp dependence of solubility on the temperature.However,hazardous chemicals in industrial effluent,include phosphorate,silicate and arsenate,causing severe damage to the environment.In this work,these impurities are selectively precipitated onto inorganic flocculants,while the vanadate dissolved in an aqueous solution keeps almost undisturbed.Therefore,high purity NH_(4)VO_(3)is produced by the crystallization from the purified solution.By screening various flocculants and precipitating parameters,polyaluminum sulfate with an optimal amount of 50 g/L,is demonstrated to selectively remove phosphorate,silicate and arsenate,corresponding to the removing efficiency of 93.39%,97.11%and 88.31%,respectively.NH_(4)VO_(3)from the purified solution holds a purity of 99.21%,in comparison with 98.33%in the product from the crude solution.This purifying technology cannot only produce NH_(4)VO_(3)with high added value,but also reduce the environmental pollution of waste liquid.

A Preliminary Study on Cactus as Flocculants in Water Recycling from Moroccan Phosphates Schlamms

In this work we used a new organic biodegradable flocculants which is the cactus cladodes juice in order to recycle water from phosphate schlamms. This flocculants has enabled us to increase the settling velocity of the schlamms so consequently the water recycled degree. The study was conducted on an industrial sample of phosphates schlamms from Khouribga phosphates washing plant. The study was about the influence of concentration, pH, and velocity gradient with cactus extract leads to satisfactory results in term of settling decantation, and in water recycling degree which is 93%.

Tannin-Based Deflocculants in High Temperature High Pressure Wells: A Comprehensive Review

Clay deflocculants that are commonly used in water-based muds under high temperature high pressure (HTHP) oilwell drilling conditions have been found to contain chromium which is toxic. Tannin-based deflocculants are regarded as a more environmentally friendly and suitable alternative to the chrome-based deflocculants. However, tannin-based deflocculants have not been studied extensively and understood completely, and for the past two years, there have not been many active pieces of research in the area. To advance research in the area, there is a need to critically and holistically review research works that have been done so far on tannin-based deflocculants as drilling mud additives to identify research challenges and opportunities. This review paper provides an overview of tannin-based deflocculants used in water-based muds under HTHP drilling conditions, including the various forms, thermal stability, deflocculating ability and environmental acceptance of the deflocculant. The review revealed that under HTHP conditions, modified and unmodified tannin-based deflocculants both deflocculate water muds well and are thermostable. However, only a few studies have been conducted on their usage as deflocculants at temperatures of 150ºC or above. The research gaps identified if pursued could advance the use of tannin-based deflocculants as green substitutes for the conventional chrome-based deflocculants.

Shear hydrophobic flocculation and flotation of ultrafine Anshan hematite using sodium oleate

Effects of stirring speed and time, pH and sodium oleate concentration on the shear hydrophobic flocculation of ultrafine Anshan hematite with sodium oleate as the surfactant were discussed. The results show that these parameters significantly affect the shear hydrophobic flocculation of ultrafine hematite. The optimum conditions for the flocculation are： stirring speed 1 400 r/min, flocculation time 20 min, pH 9 and sodium oleate concentration 3.94×10-4 mol/L; the flotation recovery of hematite flocs is remarkably high compared with non flocculated ultrafine hematite. According to the extended DLVO theory, the total interaction potential of Anshan ultrafine hematite was determined. The calculation results indicate that the hydrophobic flocculation state of the ultrafine hematite-sodium oleate system is mainly dominated by electric double layer repulsive interaction potential and hydrophobic interaction potential. A mechanical agitation is required to impart particles a kinetic energy to overcome potential barrier between them due to the existence of electric double layer repulsive interaction potential. Those particles further approach to form flocs due to the significant increase of the hydrophobic interaction potential.

Biological preparation and application of poly-ferric sulfate flocculant

A novel inorganic polymer flocculant,poly-ferric sulfate（BPFS） was prepared by oxidation of ferrous sulfate using domestic Thiobacillus ferrooxidans（T·f） under acid condition.The optimal conditions for the preparation were pH value of 1.5,（NH4）2SO4 dosage of 0.5 g/L,initial Fe2＋ concentration of 45g/L,inoculum 10%,rotating speed of 120 r/min,reaction time of 5-6 d and reaction temperature of 30 ℃.Under the optimal conditions,the BPFS product with pH value of 1.5-2.2,basicity of 17.5%-22.7% and total iron content of 43.87-45.24 g/L was obtained.The application of the BPFS to three wastewaters was carried out,and the removal efficiencies of COD,decolorization and Zn2＋ by BPFS can be reached 70%,90% and 99%,respectively.The result suggests that the BPFS is an excellent flocculant for water treatment.

Treatment of Wastewater in Chemistry Laboratory through Flocculent Settling and Constructed Wetlands

The basic chemistry laboratories of three colleges and universities in Guizhou Province were investigated completely,especially the pollution situations of the basic chemistry projects were counted,and the discharge amounts of the poisonous and harmful pollutants in the waste liquid from laboratories were monitored and analyzed.On the basis of the summing-up and analysis of the current research findings,a simple and feasible treatment scheme through flocculating,precipitating and constructed wetlands was designed to control the three kinds of excessive pollutants.

Screening of One Microbial Flocculant for Treatment of Methyl Orange Wastewater and its Decolorization Effect

[Objective] To screen out a microbial flocculant with good decolorization effect on methyl orange wastewater,and study the effect of different cultural conditions on decolorization effect of methyl orange.[Method] Absorbance of methyl orange solution before and after decolorization was determined by spectrophotometer,and the decolorization rate was calculated to compare the effects of different cultural conditions on removal rate of methyl orange.[Result]An optimal actinomycete stain（F-1-2） was screened out,and the best cultural condition was as follows：with sucrose as carbon source and NaNO3 as nitrogen source,cultured in constant temperature oscillator at 150 r/min,30℃ for 72 h.Under the optimal condition,the removal rate against methyl orange could reach 68.4%.[Conclusion]Different culture conditions have great impact on decolorization effect of strain.