Coagulation & Flocculation

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.

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

This review suggests the concept of the best available technology of water/wastewater treatment and seawater desalination
which is in fact a simulation of the seawater distillation at the open sky: coagulation in salty water aerated basin/
coagulation using seawater as coagulant solution with distillation using stored solar energy followed by waterfall on a
natural mountain. This natural, green, and technico-economical technology is composed of three steps: the first one is
coagulation which may be achieved: 1) in salty water aerated basin (air stripping, AS; dissolved air flotation, DAF)
where the raw water is “diluted” in seawater; or 2) in “conventional” coagulation using seawater as coagulant solution
instead of alum/ferric salts. The first option seems to be more natural as it simulates river water dilution in seawater and
the second one is more practical for “rapid” water consummation. For colloids and microorganisms’ removal, doublelayer
compression and charge neutralisation, as main coagulation and disinfection mechanisms, would be involved in
the first and second options, respectively. Aerated basin (AS/DAF) reproduces the natural aeration to simulate healthy
natural water basin. Using stored solar energy, distillation as the best liquid-solid/liquid-liquid separation process provides
the removal of dissolved pollutants. For well balanced calco-carbonic equilibrium, the last step of this green
treatment is the waterfall on a natural mountain providing useful gases, dissolved oxygen and carbon dioxide, and mineral
salts to the water.

Esta investigación tuvo como objetivo ensayar la reducción de la carga contaminante de los efluentes de una industria de cartón, empleando un coagulante industrial y floculantes naturales como ceniza de carbón vegetal y harina de cáscara de plátano

Although coagulation has historically been used for turbidity removal, drinking water regulations
have emerged in recent years expanding the use of this process beyond its traditional role to include
disinfection by-products (DBP) precursors removal. Effective removal of DBP precursors is the one
of the major challenges in modern drinking water treatment. DBP precursors are present in all
surface water supplies existing as natural organic matter (NOM), and this type of precursors can be
characterised by the following measurements of dissolved organic carbon (DOC), ultraviolet
absorbance at 254 nm (UV254), specific ultraviolet absorbance (SUVA), and disinfection by-products
formation potential (DBPFP). The effort to remove DBP precursors results in reduction of DBP
formation in potable water. However, scientists discovered that chlorination of organic matter in raw
water resulted in formation of DBPs. Because of concerns over the health effects of these organic byproducts,
several industrial countries have established limits for DBP in drinking water. The most
known chlorination by-products are trihalomethanes (THM) and haloacetic acids (HAA). The US
Environmental Protection Agency (USEPA) regulated THM and HAA in drinking water at the limit
of 80 and 60 μg L!1, respectively, while recently, the European Union countries regulated THM in
their water at the limit of 100 μg L!1. The USEPA has identified enhanced coagulation (EnC) as a best
available technology (BAT) for reducing DBP precursors in conventional water treatment plants.
Their removal by EnC depends on a variety of factors, including but not limited to, pH, alkalinity,
coagulant type and dosage, and the type and concentration of NOM. Finally, electrocoagulation (EC)
presents a robust novel and innovative alternative in which a sacrificial metal anode doses water
electrochemically. This has the major advantage of providing active cations required for coagulation,
without increasing the salinity of the water. EC is a complex process with a multitude of mechanisms
operating synergistically to remove pollutants from the water. EC has the potential to remove
efficiently DBP precursors which are essentially negative dissolved species by cationic charge
neutralisation/electrical field oxidation/metal hydroxides adsorption. This paper tries briefly to
describe NOM removal by coagulation, EnC and EC and shows that EC seems a priori to be the next
future process step from coagulation passage via EnC process. However, the application of EnC to
maximise removal of organics may not necessarily result in attainment of stringent levels of THMs
in drinking water where chlorine is used as disinfectant. This is due to the concentration of residual
DOM that is recalcitrant to removal by coagulation. This problem does not occur when the EC
process is used, since disinfection is assured by EC itself. Consequently, more studies on application
of EC as a substitute of chemical coagulation/disinfection at an industrial level must be done with
NOM characterisation to optimise this process.

Polymer industries generate significant amounts of effluent which has to be treated before being discharged into water stream. So far, very little attention has been paid towards polymer effluent treatment by physio-chemical process. In the present study, chemical coagulation–flocculation process was used to separate solids from industrial polymer effluent in order to make the effluent dischargeable with suitable characteristics. Aluminium sulphate [Al2(SO4)3] and anionic polyacrylamide (Magnafloc155) were used as coagulant and flocculant respectively. Sulphuric acid (H2SO4) and lime solution [Ca(OH)2] were used to adjust the pH values during the treatment process. A series of jar tests were conducted with different values of pH and dosing amounts of coagulant and flocculant. After each test, the supernatant layer of treated effluent was analysed for chemical oxygen demand (COD), suspended solids (SS), colour and turbidity. The process efficiency varied between 10 and 98% in COD removal, between 23 and 91% in suspended solids removal and between 37% and 99% reduction in turbidity. The optimal working pH value for coagulation was found to be 6 and that for flocculation was 8. The optimal doses of coagulant and flocculant were 7.5 mL/L of effluent. These jar testing results have been further proved by a successful pilot scale trial at the polymer plant with 1000 L effluent in an intermediate bulk container (IBC) using the same optimal values of the jar tests, which indicates that the chemical coagulation and flocculation process is a feasible solution for the treatment of effluent generated at polymer industry.

Dye effluent from textile industries is one of the most difficult types of wastewater to treat. There has been exhaustive research on the removal of dyes from textile wastewater by adsorption and coagulation-flocculation processes. This research is split up in two study parts. The first part shows an overview of the design and operation of the existing treatment facilities by the textile industries in Bangladesh. The second part of this study examines the removal efficiency of textile dyes at the tertiary level for the effluent of one textile industry, Masco Industries Ltd, deploying an integrated approach by an enhanced coagulation-flocculation method using a multispectral coagulant-flocculent called all poly floc (APF) and then, filtering the supernatant through a special media called activated filter media (AFM). The experiments were done batch wise in beakers and using a continuously operated column setup.

The results obtained by the batch tests show that AFM has a very poor adsorbent capacity (0.88Pt.Co./gm) compared to traditional adsorbents used by the textile industries. A high removal efficiency was observed by the coagulation-flocculation process. When experimentally comparing the difference between APF and aluminium (as conventional coagulant), the APF was found very effective and much better than aluminium. The removal efficiency with APF was observed as 64%, while for aluminium, it was only 33%. As filter medium, tested in a column reactor, AFM was found ineffective to remove color from the feed wastewater and the supernatant after coagulation-flocculation. Moreover, this research investigated the removal efficiency of local sand against AFM filter medium, where the local sand shows better performance in order to filter out the remaining flocs from the supernatant (after coagulation-flocculation). The removal of flocs was achieved around 38% by the local sand (size: 0.13-0.25 mm), while around 19% was achieved by AFM grade-1 (size: 0.46-1.0 mm). Finally, this report includes the results obtained by a pilot study using a combination of APF and AFM at Masco Industries Ltd based on the optimum coagulant dosage (1ml/L) obtained by the batch tests and at a fixed flow rate (1m3/h). The result shows that the retention time given for flocculation inside a pressure tank was not enough to achieve the same removal as was observed for the column tests.

"This review discusses the hydrophilic/hydrophobic ratio as a function of the hydrophilic
and hydrophobic contents removal by coagulation process. It is well established that coagulation
process could bring a reduction in dissolved organic carbon of around 30–60% by increasing the
coagulant dose and optimising reaction pH, in which large organic molecules with hydrophobic
property was removed preferentially. Furthermore, the literature affirmed that the greater removal
of UV-absorbing substances indicates that alum coagulation preferentially removed the hydrophobic
fraction of the total organic carbon. For the hydrophobic fraction, it needs to be removed
entirely without its transformation into hydrophilic fractions by coagulation process avoiding
pre-chlorination/pre-oxidation due to the risk of organic molecules fragmentation. Determining
the exact numerical values of the hydrophilic/hydrophobic ratio for raw water and treated water
at different stages of the treatment processes in a water treatment plant, as for the DCO/DBO5 ratio
in the case of wastewater treatment, would help on more focusing on OM control and removal"

This study focused on the performance of dragon fruit foliage as a natural, plant-based coagulant to replace chemical coagulants for the treatment of three-phase decanter palm oil mill effluent (POME). Palm oil mill effluent is a high strength wastewater with high chemical oxygen demand (COD), suspended solids (SS), and turbidity as compared to other sources of POME in mills. The first objective of this study was to determine the optimum operating conditions of the coagulation-flocculation process using the plant-based coagulant in terms of pH and dosage. The second objective was to measure the percentage removal of COD, SS, and turbidity using the coagulant to treat the POME. The pH values and dosages used in the coagulation-flocculation process were in the range of two to ten and 300 mg/L to 800 mg/L, respectively. This study revealed that the optimum percentage removals of COD, SS, and turbidity were 48.7%, 98.8%, and 99.2%, respectively, at the best operating conditions of pH 2 and a coagulant dosage of 300 mg/L. In conclusion, the dragon fruit foliage, plant-based coagulant was found to have potential and could be used in the pretreatment stages to substitute chemical coagulants for the treatment of POME.

It is well established that the drinking water treatment has several disadvantages such as it
may rupture the algae, thereby releasing the taste- and odour-producing oils before the
whole algae are removed from the treatment system. This review aims to present the concept
of algae recovery instead of its removal in drinking water treatment plant. Control of algae
in water supplies and some coagulation/flocculation and electrolysis experiments as harvesting
methods are discussed. In fact, algae recovery instead of its removal in water treatment
plant is a promising perspective and a suitable issue when the surface water comes from
dams where algae blooms occur frequently. Micro-algae are a sustainable energy resource
with great potential for CO2 fixation. The micro-algae could be grown in photo-bioreactors
or in open ponds. A new interesting field of research would be fast and simultaneous algal
biodiesel production with drinking water treatment in the biodiesel production/water treatment
plant without chemicals. However, the fact that algal cultivation needs light and space
would be very difficult challenge.

While the solar water disinfection (SODIS) method of treating microbiologically contaminated water at the household level has proven to be effective at reducing incidence of diarrhea, its effectiveness is limited to waters of low turbidity. This study investigates the use of table salt (NaCl) to reduce turbidity in water containing dispersed colloidal clay particles as a means of expanding the user base of SODIS. Jar tests were performed on solutions of a low-activity clay, simulating the general composition of soils of the Vertisol type, which are found in key developing regions. Results show that dispersions exhibited as high as 92% particle removal efficiency. The results of this study suggest that NaCl in combination with as little as 30% bentonite by mass may be used to produce a small-scale jumpstart effect by reducing turbidity to a level suitable for SODIS treatment. Soil type was mapped and overlaid with population estimates in a GIS environment to highlight geographic areas where salt+SODIS may be most viable in the case study of South Sudan. Findings suggest that the NaCl method could expand access to SODIS technology by about 1.56 million people who currently lack access to an improved water source in the case study.

Deposition of complex and heavy organic compounds, which exist in petroleum crude and heavy oil, can cause a number of severe problems. To prevent deposition inside the reservoir, in the well head and inside the transmission lines, it is necessary to be able to predict the onset and amount of deposition due to various factors. In the present paper, the mechanism of asphaltene deposition, which is the major cause of most organic deposition cases, is modeled based on statistical mechanics of polydisperse polymer solutions joined with the kinetic theory of aggregation and its predictive capability is discussed. Utilization of statistical mechanics of polydisperse polymer solutions joined with kinetic theory of aggregation enables us to develop a realistic model which is able to predict both reversible and irreversible heavy organic depositions. The present model is capable of describing several reversible and irreversible situations, such as the phenomena of organic deposition, growing mechanism of heavy organic aggregates, the size distributions of precipitated organics and the solubility of heavy organics in a crude oil due to variations in oil pressure, temperature and composition. As an example, the present model is applied for heavy organics deposition prediction of two different Brazilian crude oils for which experimental data are available. It is shown that the prediction results of the present model are in good agreement with the experimental data.

Landfill leachate consists mostly of a high content of refractory organic matter, ammonia and toxic compounds. All of these compounds, regardless of their nature, have a potential pollution effect on local ground and surface waters. In this context, the purpose of the present study was to evaluate a treatment process (coagulation-flocculation with lime coupled with nanofiltration) applied to landfill leachate from Seropédica, Rio de Janeiro (Brazil). Jar tests were conducted to determine the optimum dosage of lime (ranged from 0 to 10 g L-1) and, at optimum lime dose, ammonia nitrogen was removed during coagulation-flocculation process due to high pH. The process was settled for 6 h with slow stirring (50 rpm) to promote air entrainment and NH3-N stripping before using the final treatment step of nanofiltration at 8 bar. After ammonia stripping, NH3-N was reduced from 1236 mg.L-1 to 353 mg.L-1 (71% removal efficiency). At the end of the combined treatment, TOC (Total Organic Carbon), HS (Humic Substances) and COD (Chemical Oxygen Demand) removals were 89%, 80% and 94%, respectively. The results showed that the combined process was effective in the removal of recalcitrant compounds and NH3-N.

Bu çalışmada, kömür hazırlama tesisi atıksuyunun katı-sıvı ayırımı işlemine tabi tutulmasında, yeni nesil UMA (Unique Molecular Architecture) teknolojisi bir flokülantla geleneksel bir flokülantın flokülasyon performansları araştırılmış, performans kriterleri olarak çökelme hızı ve bulanıklık (türbidite) değerleri esas alınmıştır. Hem Hydrofloc 7170 hem de Magnafloc 4240 için en yüksek çökelme hızı ve en kötü bulanıklık değerleri süspansiyonun doğal pH’sı civarında elde edilmiştir. Her iki flokülantla 30 sn’nin altındaki karıştırma sürelerinde yüksek çökelme hızları elde edilmiş, buna karşın bulanıklık değerleri yükselmiştir. 100 D/D (devir/dak) üzerindeki karıştırma hızlarında çökelme hızı azalırken bulanıklık değerlerinde belirgin bir iyileşme meydana gelmiştir. 300 mm/dak optimum çökelme hızına ulaşmak için ton başına tüketilen Hydrofloc 7170 miktarı 42,74 g/ton-katı, bulanıklık değerlerinde az bir kötüleşmeyle harcanan Magnafloc 4240 miktarı ise 34,2 g/ton-katı’dır. Laboratuar ölçekte yapılan çalışmalar, Hydrofloc 7170 yerine UMA teknolojisi Magnafloc 4240 kullanıldığında yıllık flokülant tüketiminde %54 oranında bir azalmanın ve 24000 €’luk bir kazancın olabileceğini göstermiştir.

The objective of this study was to evaluate the coagulation-flocculation process in the clarification of leachate from the landfill Technical Center of Souk-Ahras city using three coagulants based on iron: ferrous sulfate FeSO4.7H2O; ferrous chloride FeCl2.4H2O and ferric chloride FeCl3. The influence of some parameters namely pH leachate, dose and nature of coagulant and nature of flocculant was studied. The best treatment efficiency was obtained at 20 % of FeCl3 giving a turbidity of 4.09 NTU with pH adjustment of the raw leachate at acidic pH (3.5 ± 0.2) before coagulant addition and at a basic pH (7.5 ± 0.2) after addition of coagulant. The iron valence and the nature of anion at which is linked, played a determinant role in the clarification of leachate. The treatments made with ferric chloride in the presence of a flocculant have proved that the starch was more efficient than lime giving abatement rates of 99 % for COD and 85 % for BOD5.

Coagulation and flocculation processes could reduce particulate algal cells efficiently , but they are not so performant in dealing with solubilized algal organic matter in potable water factories. This work reviews the main findings found in recent publications. Many techniques used in the water treatment industry encounter the problem of microalgae lysis, toxin release, and degradation. Indeed, chemical coagulants such as alum and pre-oxidation injecting chlorine can trigger demolition to algal cell integrity leading to the release of intracellular organic matter. As suggestion, chlorination could be decreased to the disinfection (i.e., before sand filtration) averting pre-disinfection and keeping the post-disinfection. Moreover, algae recuperation instead of its removal in drinking water treatment plants remains an encouraging outlook especially if the surface water arrives from dams where algae blooms happen usually. Algae remain a sustainable energy resource with a huge capacity for CO 2 fixation. The micro-algae could be developed in photo-bioreactors or in open ponds. A fresh attracting domain of investigation would be fast and simultaneous algal biodiesel production with drinking water treatment in the biodiesel production/water treatment plant without chemicals use.

The present study deals with the treatment of simulated pulping effluent (pH = 11, and total organic carbon (TOC) = 1900 mg/L) by acid precipitation and coagulation-flocculation processes. The maximum TOC removal (= 4845 mg/g Al3+) from the effluent was found with Al2(SO4)3 coagulant. Addition of sufloc (a flocculant) improved the sludge settling significantly. Hydrolyzed mono- and polynuclear species generated from Fe and Al coagulants could have resulted in TOC removal. Thermal analysis of sludge showed release of gases like CO, CO2, HCHO, CH3SH and SO2 during combustion. Afterwards, the dissolved metal species in treated wastewater samples should be removed.

The processes of coagulation and flocculation using high molecular weight long-chain polymers were applied to treat mine water having fine flocs of which about 93% of the total mass was less than 3.02 m, representing the size distribution of fine particles. Six different combinations of acryl-type anionic flocculants and polyamine-type cationic coagulants were selected to conduct kinetic tests on turbidity removal in mine water. Optimization studies on the types and concentrations of the coagulant and flocculant showed that the highest rate of turbidity removal was obtained with 10 mg L-1 FL-2949 (coagulant) and 12 mg L-1 A333E (flocculant), which was about 14.4 and 866.7 times higher than that obtained with A333E alone and that obtained through natural precipitation by gravity, respectively. With this optimized condition, the turbidity of mine water was reduced to 0 NTU within 20 min. Zeta potential measurements were conducted to elucidate the removal mechanism of the fine particles, and they revealed that there was a strong linear relationship between the removal rate of each pair of coagulant and flocculant application and the zeta potential differences that were obtained by subtracting the zeta potential of flocculant-treated mine water from the zeta potential of coagulant-treated mine water. Accordingly, through an optimization process, coagulation-flocculation by use of polymers could be advantageous to mine water treatment, because the process rapidly removes fine particles in mine water and only requires a small-scale plant for set-up purposes owing to the short retention time in the process.

http://www.ncbi.nlm.nih.gov/pubmed/20450117 
http://www.tandfonline.com/doi/abs/10.1080/09593330903513245#.Ut31zvsRWM8

In this study, the flocculation performance of new generation of flocculants (Magnafloc 5250 and 6250) namely unique molecular architecture (UMA) and conventional polyacrylamidebased SB 1836 was investigated for the solid-liquid separation of travertine processing wastewater. The settling rate and turbidity values were considered as the performance criterions. Based on the settling rate and turbidity values, the anionic UMA flocculant 6260 showed a better performance compared to the other anionic flocculants, SB 1836, which is currently used in the travertine processing plant, and the UMA flocculant 5250. The results obtained from this study clearly indicated that the type of the flocculants showed no significant effect on the adsorption of the polymers on the travertine particles at natural pH. The settling rates of the travertine particles and the turbidity of the suspensions were greatly affected by the surface charge of the flocculants at high and low pH regimes. The flocculation tests with the medium charge flocculants (Magnafloc 5250 and SB 1836) were slightly affected by pH, and resulted in poor performance in terms of turbidity.

Deposition of complex and heavy organic compounds, which exist in petroleum crude and heavy oil, can cause a number of severe problems. To prevent deposition inside the reservoir, in the well head and inside the transmission lines, it is necessary to be able to predict the onset and amount of deposition due to various factors. In the present paper, the mechanism of asphaltene deposition, which is the major cause of most organic deposition cases, is modeled based on statistical mechanics of polydisperse polymer solutions joined with the kinetic theory of aggregation and its predictive capability is discussed. Utilization of statistical mechanics of polydisperse polymer solutions joined with kinetic theory of aggregation enables us to develop a realistic model which is able to predict both reversible and irreversible heavy organic depositions. The present model is capable of describing several reversible and irreversible situations, such as the phenomena of organic deposition, growing...

Abstrak
Seringkali pengolahan Limbah hasil industri besar tidak sesuai dengan peraturan yang berlaku pada pemerintah setempat. Limbah hasil pengolahan industri yang tidak sesuai ini di buang pada lingkungan penduduk tanpa memperhatikan dampak terhadap masyarakat sekitar. Dalam pengolah Limbah hasil industri, Limbah jenis cair yang akan berhubungan langsung dengan lingkungan masyarakat. Pengolahan Limbah yang tidak maksimal bisa berakibat Limbah cair memiliki kandungan lumpur. Kandungan lumpur ini akan mengakibatkan kejernihan air serta nilai pH dengan nilai di atas rata-rata yang diizinkan. Masalah ini dapat dikurangi dengan mengotomasi pengontrolan kandungan lumpur, kejernihan air, dan nilai pH pada pengolahan Limbah. Sistem pengolahan Limbah ini terdiri dari dua pengolahan. Pertama kandungan lumpur yang terkandung dalam Limbah akan dikontrol kekeruhannya dengan sensor LDR dan diolah dengan metode floccuration. Teknik tersebut akan memisahkan lumpur dengan air. Pada pengolahan kedua nilai pH yang terkandung dalam Limbah akan dikontrol dengan pencampuran cairan asam atau basa dan pengukuran kadar keasaman air menggunakan sensor pH meter analog. Sistem memproses hasil tersebut agar dapat mengatur waktu terbukanya pintu otomatis dan hasil olahan Limbah akan dibuang. Hasil akhir dari perancangan sistem ini adalah kualitas Limbah yang dihasilkan akan lebih aman bagi lingkungan. Yaitu berkurangnya kandungan lumpur, bertambahnya kejernihan air dengan nilai maksimal 20 NTU serta nilai pH yang dihasilkan netral (pH 6 – 8). Kata kunci : Limbah cair industri, sistem pengontrolan otomatis, floccuration.

Abstract
Mostly the processing of large industrial waste does not comply with the regulations that apply to the local government. These unsitable industrial wastes are disposed in the local population with regardless of the impact on the surrounding peoples. In the industrial waste result process, the liquid wastes that will be direcly related to the people's environment. Some unsuitable wastes contain amount of mud. This mud could makes the clarity of liquid wastes and pH value with below average value that permitted. These problem could be reduced by automating treatment control of mud content, the liquids clarity, and pH value. This treatment system will be consist by two different process. First the mud that contained in the waste will be control the turbidity with the method called floccuration and the result will be monitored by LDR sensor as a feedback. This method will separate the liquid and the mud. At the second process, the liquid that contains unsuitable pH would be treated by mixing acid and alkali. Furthermore the monitoring of the pH value would be using pH Meter Analog sensor. Systems would proccess it automaticly that will adjust when its ready to be disposed for environment. The goal of this system design are the quality of liquid wastes would be more acceptable for envornment. That will be nociced by decreased the amount of mud at the liquid, increasing the liquid's clarity by the maximum value 20 NTU, and netralized the pH value with the target of pH contains between 6 to 8.

The settling behaviour of Etiholding Kirka Borax Concentrator tailings has been investigated using different types of anionic and nonionic polymers and coagulants as well. The most effective polymer in flocculating the tailings is found to be Magnafloc 342 at a dosage of 1176 g/ton-solids. As the tailings are composed of mostly calcite and dolomite type carbonaceous minerals, the effect of nonionic polymer, Magnafloc 351, which is known to be effective clay minerals, is found to be minimal. The anionic polymer (Magnafloc 342) is envisaged to adsorb onto oppositely charged solid surface through electrostatic attraction followed by polymer bridges. While the addition of saturated borax to the suspension affected settling marginally, that of water improved the settling. This reveals that physicochemical properties of minerals in the tailings and polymer dosages are crucial parameters in dictating the level of settling. In order to decrease the consumption of polymer, an alternative sedimentation scheme such as the use of coagulant was tested. Nevertheless, the use of coagulants neither alone nor in combination is shown to produce adequate settling

The natural organic matter in the water continuously affects the treatment units due to their transformations. The NOM characteristics are complex, and it is challenging to clarify and remove the NOM in water. Due to the modifications of NOM during the disinfections, which results in the formation of by-products, their removal is problematic and causes adverse effects on human health. Several techniques are adopted to remove NOM from the water; one standard method involves coagulation and similar processes. The current review provides insights about the methods available for removing the natural organic matter and highlights the coagulation techniques that are gaining prominence in the current scenarios to remove the NOM from the various sources.

This paper focuses on the possibility of applying physiochemical treatment for industrial wastewater combined with domestic wastewater that are currently treated by the conventional activated sludge process in Khartoum North Treatment plant at Haj Yousif (Wad Dafeah). A lab-scale experiment was carried out utilizing Poly aluminum chloride (PAC) as a coagulant for determining the optimum dose to reduce the turbidity of the wastewater sample to the lowest level. The results of the lab-scale model showed that a dose of 0.8 ml/l of the PAC achieved significant removal of turbidity (from turbidity >1000 NTU of raw sewage to turbidity level of 18 NTU of the treated effluent). This dose of 0.8ml/l obtained from the lab-scale experiment was applied in a pilot plant of capacity 30 m 3 /d erected at the site of the treatment plant (Wad Dafeah). The process units utilized in the pilot plant were of minimum or negligible electrical power consumption. They include an inverted hydro cyclone for flash mixing of the coagulant, pipes arrangement to achieve hydraulic gentle mixing as flocculation process, vertical sedimentation tank to enhance efficient settling of particles and tertiary treatment using a rapid sand filter. Raw sewage of BOD5 = 5000 mg/l was introduced into the pilot plant and excellent quality of treated effluent was obtained. Removal efficiencies of both BOD5 and SS were high (97 % & 98% respectively).Treated effluent had BOD5 = 23 mg/l & SS = 22 mg/l. The high dose of PAC utilized for the treatment (0.8 ml/l= 1040 mg/l) can be reduced significantly if raw wastewater of lower BOD content such as domestic wastewater is treated. In a parallel study with the domestic sewage of BOD5 =350 mg/l, the PAC dose required was 0.1 ml/l (130 mg/l). Recycling of residual PAC in the sludge is recommended to decrease the cost of treatment. The approach & methodology followed in this study can be further adopted using other coagulant material such as ferric salts or other similar local product which can achieve high efficiency in reducing the load of organic substances in the wastewater with minimum cost.

Coagulation remains a technique by which finely dispersed solids are efficiently eliminated. It has been largely expanded and remains the most unavoidable method for treating water. This review focuses on colloid stability, coagula-tion mechanisms, and coagulant types. It presents electrocoagulation as an option of conventional coagulation and discusses challenges in coagulation technology especially health hazards in used chemicals toxicity. As promising solutions, new developments in terms of using coagulants are presented. Mi-cropollutants are inorganic and organic substances that could disturb negatively nature even at very low levels. Microplastics are also observed. Coagu-lation could retain different micropollutants and microplastics at varying ef-ficiencies even if there is a need to determine running circumstances that could increase their reduction. As a perspective, coagulation may be combined with additional processes, such as ultrafiltration. Further, traditional water treatment should be deeply revised.

This research is centered on the optimization of coagulation–flocculation treatment of cosmetic wastewater. It analyzes blends of fishbone (BFB) and aluminum-based coagulant (ABC) to determine the efficacy of BFB as a potential coagulant–flocculants aid at optimum conditions using response surface methodology (RSM). The experiment was carried out employing the standard nephelometric procedure at 1000 rpm stirring rate. The central composite design (CCD) was used to examine the interactions of pH, dosage, and settling time to maximize the turbidity removal efficiency of the ABC- and BFB-driven coag–flocculation. The optimal pH, dosage, and settling time for ABC were obtained as 10, 0.1 g/L, and 2 min, while pH 6, 0.4 g/L, and settling time of 4 min were recorded for BFB following the established quadratic model of the RSM. The removal efficiency of ABC and BFB plots 80% and 88%, respectively; this corresponds to 262 NTU and 288 NTU of removal from the wastewater at optimal conditions...

Microalgae biomass is well known as potential sustainable product for the bio-based industry, which has reported encountering numerous difficulties during biomass harvesting and recovering. This study examined the effect of pH (5–12) and alum dosage (30–180 mg/L) for microalgae Botryococcus sp. harvested via flocculation technique. The optimum pH condition for Botryococcus sp. harvesting was measured at pH 9.2. Meanwhile, alum dosage was at 100 mg/L. Both of optimum values were successfully harvests the microalgae biomass up to 95%. This study revealed that flocculation efficiencies for alum are highly dependent on the range of pH and coagulant dosage that applied during the process. Use of the flocculation technique with aid of alum as a coagulant represents a convenient technique for Botryococcus sp. biomass harvesting and is recommended for use in both the small and large scale biomass industry.

It is a substantial fact that specific disposal standard for laundry effluent have not been prescribed by Gujarat pollution Control Board (GPCB). Laundry waste uses soap, soda, detergents and other chemicals for removal of stains, oil, grease and dirt from the soil clothing. The laundry waste is originated in the residential zone on account of manual cleaning, cleaning by domestic washing machines as well as large amount of effluents are generated by commercial washing including dry-cleaning. An attempt has been made in the present investigation to generalize the characteristics of laundry effluent generated by various sources in Vadodara (Gujarat). It has been found during the laboratory studies, that SS, BOD and COD of laundry waste are high. Treatability studies were carried out in the environmental engineering laboratory of B.V.M. Engineering College, V.V.Nagar for removal of these contaminants. The coagulation-flocculation followed by dual media filtration was found to be most suitable sequence of the treatment.

"The Selection of Flocculants and other Solid-Liquid Separation Aids

INTRODUCTION

The use of chemical additives, such as flocculants, is a common step in solid-liquid separation operations. The correct selection of agent is an essential part of the design of such processes. Many excellent reviews and guides deal with this topic, and the interested reader is referred to works such as [l-4]. In particular the Harwell-Warren Spring Report “The Use and Selection of Flocculants" provides a good overview on the application of coagulants and flocculants. This section does not attempt to reproduce a detailed treatment of that kind; instead it is our intention to state a few general rules and principles concerning methods of choosing an additive, and to illustrate briefly their application in practice.

The types of agents employed in solid-liquid separation fall into ...

0 FLOCCULANTS: BASIC PRINCIPLES
0.1 Coagulants and Flocculants
0.2 Surfactants
0.3 Dispersants

1 FLOCCULANTS: TEST PROCEDURES AND METHODS
1.1 Those Applicable to the Original Suspension
1.2 Those Applicable to the Flocculant Solution
1.3 General Tests Applicable to the Flocculation Process
1.4 Specific Tests Applicable to the Flocculation Process
and to the Flocculation System

2 EXAMPLES
2.1 Formation of M729 Vermiculite / Glass Fibre
Refractory Paper
2.2 Harvesting and Concentration of a Filamentous
Organism Suspension before Isolation of a
Pharmacologically-Active Compound

3 USE OF SURFACTANTS TO HELP REDUCE
FILTER-CAKE MOISTURE

4 REFERENCES
"
More Info: GBHE SPG PEG 307
Publication Name: The Selection of Flocculants and other Solid-Liquid Separation Aids
Research Interests:
Coagulation & Flocculation, Coagulation Optimization, Analytical Chemistry, and Chemistry

Microalgae biomass has been recognised as a sustainable bio-product to replace terrestrial biomass in biofuel production. The microalgae industry has high operating costs, specifically on harvesting and biomass recovery. Therefore, the development of an efficient harvesting method is crucial to the minimisation of production cost. A statistical analysis via response surface methodology was used to investigate the optimisation of harvesting efficiency using alum and chitosan as a coagulant. Growth rate and biomass productivity were also determined. This research revealed that the harvesting efficiency using alum was 99.3%, with optimum dosage and pH of 177.74 mg/L and 8.24, respectively. Chitosan achieved 94.2% biomass recovery at an optimal dosage of 169.95 mg/L at pH of 12. Moreover, Botryococcus sp. achieved the maximum growth of 0.7551 µmax.day-1, with an average total biomass productivity of 9.81 mg.L-1.day-1 in domestic wastewater. Overall, this study shows that both alum and c...