Alum Coagulation Research Articles

Assessment of water treatment residuals as sorbent material in permeable reactive barriers: Application to a copper‐contaminated site

AbstractThe objective of this study is to design a pilot‐scale permeable reactive barrier (PRB) for the removal of copper from groundwater in Keweenaw Peninsula, Michigan. The reactive material selected for the barrier is drinking water treatment residuals (WTR)—the residuals of alum coagulants used in a local drinking water treatment plant. Physical and chemical properties of the WTR were determined. Synthetic precipitation leaching procedure tests indicated the concentrations of hazardous elements leached from the residuals do not exceed U.S. Environmental Protection Agency limits and, hence, can be safely recycled as PRB material. Batch reactor tests showed that equilibrium sorption of copper is high and fits a Langmuir‐type isotherm. Site characterization studies included groundwater flow direction, pore water velocity, and contaminant concentration to determine optimal dimensions and placement of the PRB. Permeameter tests were performed with various mixtures of the WTR and an inert support material (pea gravel) to determine the ideal mix to match the hydraulic conductivity of the field site. Kinetic and column experiments were conducted to understand the significance of chemical and physical mass transfer limitations. Based on the results, dimensions of a PRB to meet the Michigan Department of Environmental Quality target level of 0.031 milligrams per liter (mg/L) total Cu were calculated.

RESEARCH OF PROCESSING TECHNOLOGY OF N-CONTAINING LIQUID WASTE OF AMMONIUM SULPHATE PRODUCTION BY THE REAGENT FLOTATION

Coke wastewater is characterized by a significant content of bound nitrogen in various forms, therefore, can be considered as N-containing liquid waste. The main polluting agents of this type of waste are resinous substances. The presence of surfactants also characterizes the total coke-chemical effluent as a stable emulsion system. Flotation methods for cleaning liquid waste from resinous substances have significant technological advantages (simplicity of instrumentation, high productivity, lack of regeneration stage). Increase the depth of de-oiling of liquid waste during flotation is possible due to the coagulation of particles of a colloidal degree of dispersion - emulsified resinous substances. This is achieved by using flotation, in particular, when inorganic electrolytes (often FeSO4) are added to the wastewater. The process of reagent flotation of sewage waters of PJSC Dniprodzerzhynsk Coke Plant with a tar content of 394 mg/dm3 with the addition of coagulants (AlCl3, FeSO4, Al2(OH)5Cl) and flocculants based on polyacrylamide (A3330, CW3279) was investigated. It has been experimentally proved that the addition of 4 mg/dm3 of the anionic flocculant A3330 in reagent flotation with the use of Al2(OH)5Cl at a dose of 25 mg/dm3 allows recovery of resinous substances to 15 mg/dm3 and shortens the duration of the cleaning process by 30 % method of pressure flotation. The regularities of the effect of water temperature in the interval 284-323 K on the efficiency of flotation removal of resinous substances are established. In this interval, an increase in the temperature of the wastewater reduces the duration of the pollutant recovery to the normative content from 30 min to 15 min with the use dose of 25 mg/dm3 Al2(OH)5Cl and anionic flocculant A3330 in the amount of 4 mg/dm3. The possibility of saving the coagulant Al2(OH)5Cl by replacing part of its dose during flotation with cheap FeSO4 without reducing the efficiency of purification is shown.

Development of statistical models for trihalomethane (THM) removal in drinking water sources using carbon nanotubes (CNTs)

This research developed models using the multiple linear regression technique for prediction of trihalomethane (THM) removal from chlorinated drinking water sources through a combination of a coagulation process with carbon nanotubes (CNTs). Terkos Lake water (TLW), Buyukçekmece Lake water (BLW) and Ulutan Lake water (ULW) samples were coagulated by a conventional coagulant (alum) and increasing doses of single-walled carbon nanotubes (SWCNTs) and multi-walled carbon nanotubes (MWCNTs) with the addition of alum. Also, chlorination experiments were conducted with water reservoirs from TLW, BLW and ULW, with different water quality regarding bromide concentration and organic matter content. The factors studied affecting THM removal were contact time, chlorine dose, coagulation process, total organic carbon (TOC), and specific ultraviolet absorbance (SUVA). Statistical analysis of the results focused on the development of multiple regression models, as Models 1 and 2, for predicting total trihalomethane (TTHM) based on the use of contact time, SWCNTs and MWCNTs doses, chlorine dose and TOC. When the two models were compared, Model 1 proved best suited to describe THM removal for the three water sources. The developed models provided satisfactory estimations of THM removal; the model regression coefficients for Models 1 and 2 were 0.88 and 0.77, respectively. Furthermore, the root-mean-square error (RMSE) values of 0.083 and 0.126 confirm the reliability of the two models. The results show that THM removal can be simply predicted by using the multiple linear regression technique in chlorinated drinking water sources.

PENGGUNAAN KOAGULAN (TAWAS) DALAM PROSES PENJERNIHAN AIR DI LINGKUNGAN PADANGLOLO KELURAHAN KASSA KECAMATAN BATULAPPA KABUPATEN PINRANG

Water is the main element of life. In terms of quantity, water must meet all the needs andactivities of daily living in accordance with the level of community life, because water is asource for life. And in terms of quality, water must meet the requirements of clean waterquality according to Peraturan Menteri Kesehatan Republik Indonesia No. 416 /MENKES / IX / 1990 on terms of water quality in terms of physical, microbiological,chemical, and radioactive water. There are various simple ways that we can use to getclean water, one of the processes undertaken to reduce the turbidity of the water is bycoagulation process, The process of coagulation is the process of collecting particles thatcan’t precipitated deposited turbidity by gravity, into particles larger so it can beprecipitated by coagulant chemicals (alum). Alum serves to separate and precipitateimpurities in water. The purpose of this activity is to give understanding to the residentsin Padanglolo Environment about the importance of utilization of clean water that fulfillthe requirements in accordance with the Peraturan Menteri Kesehatan RepublikIndonesia No. 416 / MENKES / IX / 1990. From the data obtained that people in theenvironment Padanglolo for utilization of clean water facilities still have not reached thetarget, where the percentage that does not use clean water that is as much as 92% (323people). After counseling and demonstration of coagulant (alum), the community hasbegun to understand and understand about the impacts caused by consuming water thatdoes not meet health requirements.

THE EFFECTIVENESS OF DECREASING LEVELS OF CHROMIUM (Cr) USING COAGULANT FeSO4 AND Al2(SO4)3 (Research Study Batik Home Industry in The Village of Tuban Jarorejo Year 2018)

Liquid waste from the results of the process coloring or dyeing have thick, colored characteristics of pH, concentration of Biological Oxygen Demand (BOD) height and color substance in which there is heavy metal content of chromium that is alleged to be toxic. One effort to decrease it is by the process of coagulation with coagulant FeSO4 and Al2(SO4)3. This research aims to kniw the effectiveness of Cr levels decrease total between coagulant FeSO4 and Al2(SO4).This type of research is experimental with Pretest-Posttest with Control Group design research. Sample required as many as 27 samples with replication nine times for each coagulant. Analysis of data used to use multivariate anova test for the purpose of knowing the difference 2 treatment groups. Percetage of chromium levels decrease after coagulation using coagulants FeSO4 and Al2(SO4)3with their respective dose variation 20 gr/l, 30 gr/l and coagulant Al2(SO4)3with coagulantdose variation 20 gr/l, 30 gr/l in row amounted to 75,89%; 83,00%; 71,40%; 91,76%. The most effective results in decreased levels of Cr in waste liquid of batik is 91,76% with coagulant Al2(SO4)3 dose variation 30%. On the results of statistics produces the value of p< 0,05 is 0,000 the H0is rejected, which means that there is a difference in total Cr levels using coagulant FeSO4 with coagulant Al2(SO4)3.Based on the precentage of the total Cr levels decrease, effective coagulant to lower levels of total Cr in batik liquid waste is to use a coagulant Al2(SO4)3 with dose 30 gr/l. Advice for owners batik home industry by making waste watern treatment installations to process liquid waste it generates, which there is a processing unit with coagulation method that uses Al2(SO4)3coagulantto lower levels of chromium in sewage. Key words: Chromium (Cr), Coagulant, The liquid waste of batik

Perbandingan Kebutuhan Koagulan Al2(So4)3 dan PAC Untuk Pengolahan Air Bersih Di WTP Sungai Ciapus Kampus IPB Dramaga

Water Treatment Plant (WTP) IPB process water from Ciapus River by water purifying process before distributed to consumers. The type of coagulant used is Al2(SO4)3 (aluminum sulfate) or alum and Polyaluminium Chloride (PAC). This study aimed to compare the water quality by using coagulant Al2(SO4)3 and PAC in WTP Ciapus River IPB Dramaga and to find out the optimum dosage of coagulant alum and PAC . This study used a test jar method and ISO (SNI) for the analysis of physical and chemical parameters of water. Based on the results of research, PAC was better than alum with the optimum dose of 20 ppm which produces 0.22 NTU of turbidity, 1 mg/l of TSS and 150 mg/l of TDS. While the optimum dose of alum was 20 ppm which generates 0.49 NTU of turbidity, 0 mg/l of TSS and 164 mg/l of TDS. Average costs for the use of coagulant alum and PAC were Rp. 95/m3 and Rp 215/m3, while the average value of the efficient used of coagulant alum and PAC were 91.34% and 83%. The results of both coagulants meets the criteria of water quality standards in accordance with Regulation of the Minister of Health No. 429 of 2010.

The Effectiveness of Psophocarpus Tetragonolobus’s Seed as Turbidity Removal

High turbidity in water not only will reduce the quality of water itself but it can give impact to the ecosystem as well. In water treatment, coagulation and flocculation are the process involved in removing turbidity. Chemical coagulant such as aluminium sulfate (Alum) and ferric chloride are effective way and widely used in order to remove the turbidity in water. However, these chemical coagulants have a side effect in spite of the effectiveness in turbidity removal, the usage of alum and other chemical coagulants bring concerns due to its impact to the environment, human health and economy. Therefore, natural coagulant is another alternative for turbidity removal in water treatment. Natural coagulant is a plant-based coagulant which can be used to replace chemical coagulants. These coagulants are generally cheaper and safer than chemical counterparts. This research is conducted to compare the effectiveness of natural based coagulant made from Psophocarpus tetragonolobus and chemical coagulant in improving the quality of raw water. Findings from this study showed P. tetragonolobus can remove turbidity up to 60 percent with 40 ml, 1% solution. Therefore, P. tetragonolobus can be considered as a potential resource for natural coagulant.

Removal of organic matter from wastewater using M/Al-pillared clays (M = Fe or Mn) as coagulants.

This work is about organic matter removal from Sidi Bel Abbes wastewater plant (Algeria) by coagulation on pillared clays (PILCs) under pH and PZC (point of zero charge), conditions. Two pillared clays, M/Al-PILCs (M = Fe or Mn), were synthesized, characterized, and studied as coagulants. Results showed that Fe/Al-pillared clay exhibits superior efficiency, with 18% higher removal rate than the common coagulants alum (AS) and ferric chloride (FCl), and that sedimentation time has positive effect on turbidity removal, with 95.85% removal rate during 30 min. Moreover PILCs will not cause pH go down too low, which is an advantage for achieving the best overall treatment. The IR and UV bands' reduction reveals the breakdown fragmentation of high molecular weight organic substances into smaller units. The highest total organic carbon (supercritical water oxidation analysis) and chemical oxygen demand adsorption capacities (48.52% and 61.85% respectively) obtained for Fe/Al-PILC can be related to increased basal spacing between adjacent layers, creating favorable adsorption sites in the microporous system. The suggested adsorption mechanism involves strong interactions between pollutants and PILCs leading to PILC-pollutant complex formation.

Reduction of sludge formed during a coagulation treatment of Ridomil Gold by means of non-thermal quenched plasma pre-treatment.

Chemical coagulation and adsorption, despite many drawbacks, are actually the main techniques used for the removal of pollutants from aqueous solution; however, these techniques are becoming ineffective due to the exponential increase in the amount and complexity of discharged pollutants; thus, the sludge treatment process became a more complex challenge. The present study focuses on the way to reduce the quantity of sludge formed during the removal of Ridomil Gold, a widely used pesticide-fungicide in agriculture. Results revealed that pre-treatment of initial waste solution by the gliding arc (Glidarc), a source of non-thermal plasma, leads to a significant reduction of the sludge formed during the coagulation treatment. For a 20-min pre-treated effluent Glidarc followed by chemical coagulation, there was a reduction in the volume of sludge formed in the order of 90 and 80% for alum and ferric sulfate coagulants respectively without reducing the performance of pesticide removal. Therefore, there is a positive synergism between treatment by chemical coagulation and plasma treatment. These results suggest that the Glidarc can be an effective solution for the reduction of sludge obtained during treatment by coagulation.

Speciation matching mechanisms between orthophosphate and aluminum species during advanced P removal process

Aluminum (Al) salts are widely used as coagulants to remove phosphorus (P) in water treatment. However, the relationship between P and Al species and the underlying coagulation mechanisms is rarely studied. Currently, water eutrophication is a serious issue, and therefore advanced P removal is extremely necessary. Herein, the orthophosphate removal behavior of Al coagulants with various species distributions was investigated. The results showed that AlCl3·6H2O (AC) had a more pronounced P removal efficiency than polyaluminum chloride (PACl). Medium (Alb or Al13) and high polymeric species (Alc) played a more significant role in removing P than monomeric species (Ala). During coagulation, adsorption onto flocs was the dominant P removal mechanism, which could be categorized as multilayer adsorption. Although the adsorption kinetics showed that physical adsorption best described the adsorption mechanism for AC and PACl, it is worth noting that chemical adsorption also occurred during P removal by AC because of the formation of the AlPO4 precipitate. This could be because of the strong complex adsorption between the in situ Al13 species and P. Based on the excellent P removal performance, we believe these findings will have a large potential for application in advanced P removal in water treatment.

Acceleration of saturated porous media clogging and silicon dissolution due to low concentrations of Al(III) in the recharge of reclaimed water

The recharge of reclaimed water is an effective strategy for addressing the issues of water quality deterioration and groundwater level decline simultaneously. Residual Al coagulants are normally remained in the recovered water at low concentrations, and may induce clogging problems during the recharging process. However, this issue has been ignored in the past. In this study, we investigated the mechanisms of Al(III)-induced aquifer bio-clogging, the role of Al(III) in quartz sand media (SiO2) dissolution and re-precipitation in the series of aquifer columns. We determined that Al(III) resulted in serious clogging in ∼140 h at low concentrations that satisfied the national drinking water standard of China. The corresponding hydraulic conductivity decreased by more than ∼90% in the bacteria-containing aquifer, which was ∼30% greater than that for the bacteria-free trials. The enhanced Al(III)-related clogging was caused by modifying quartz sand to form Si-O-Al(OH)n and improving microbes attachment. Microbes retention kinetic coefficients (k) of the Al recharged simulated aquifer could increase by 3.0–8.3 times. The Al(III) also enhanced biomass production and clogging by binding to microbial extracellular polymeric substances. In turn, the greater amount of biomass accelerated the Si dissolution and re-precipitation, this may potentially damage the stability of aquifer structure. The results showed that reclaimed water treated with Al coagulation should be employed with caution for recharging.

Impact of Chemical Coagulants for Oscillatoria sp. Removal from Raw Water on Chemical Coagulation Process

Growing Oscillatoria sp. in freshwater causes several poisoning episodes of domestic livestock animal and human. The chemical coagulation of raw water using chemical coagulants is very simple and requiring less investment cost on equipment. These experiments used alum and PACl (Polyaluminium chloride) with alum as chemical coagulants for Oscillatoria sp. removal. The Oscillatoria sp. was prepared from Molecular and Cell Laboratory of Thailand Institute of Scientific and Technological Research and grown in BG-11 medium. The samples of treated water use chemical coagulation test to verify their efficiency of Oscillatoria sp. cells removal from the synthetic raw water. The results show that the chemical coagulation using alum coagulant and PACl with alum coagulants produces a high efficiency in Oscillatoria sp. removal. However, the PACl with alum coagulants provided the best Oscillatoria sp. removal efficiency and the low amount of chemical coagulants for Oscillatoria sp. removal process. The PACl with alum doses at 1:10 by weight, provides the best Oscillatoria sp. removal efficiency at 97%. While, the best Oscillatoria sp. removal efficiency of alum dose at 90 mg/L, is 98%. It can be concluded that the PACl with alum doses as the combined chemical coagulant provided the highest efficiency at the lowest amount of chemical coagulants used.

Combining lime softening with alum coagulation for hard Ghrib dam water conventional treatment

Combining lime softening with alum coagulation for hard Ghrib dam water conventional treatment

The Use of Alum and Polyelectrolyte Coagulants as Admixtures in Concrete Bunkers Production.

This study estimates and determines the possibility of using water treatment plant sludge as a kind of chemically enriched water cement ratio in preparing high strength concrete bunkers which are one of the most important protection barriers that soldiers usually need them and use them during wars, and gun fighting to protect themselves from bullet attacks.In this paper, two main different chemicals have been used as a concrete additives which are mainly those used in coagulation processes in water treatment plants and those two conventional chemicals were alum and polyelectrolyte which are usually have been used as a coagulants and coagulant aids in Dokan water treatment plant (70Km south west of Sulaimani city, Iraq) and they lead to produce a coagulant’s sludge waste which settled at the end of sedimentation process on the bottom of the clarifier tanks. Samples of the raw water from the inlets have been tested for a continuous period of 12months including the heavy rainy days, summer and winter seasons especially in the beginning of the stratification periods of Dokan Lake the source of the treatment plant. The tests included jar tests and turbidity of the samples, then the finding the optimum quantity of the two coagulants alum and polyelectrolytes. The records of the performed tests showed that the maximum rate of the used alum was 15mg/L while the maximum used amount of polyelectrolyte was 10mg/L. Those two maximum high values of rates of alum and polyelectrolytes and their hybrid mixing rates have been used in preparation 7concrete prototype bunkers of dimensions 80cm x 80cm x 15cm with an admixture rates of 15mg/L alum, 15mg/L polyelectrolyte, 10mg/L alum, 10mg/L polyelectrolyte , 10mg/L alum with 5 mg/L polyelectrolyte, 5 mg/L alum with 5 mg/L polyelectrolyte and zero mg/L for both of them (blank). Two different types of tests have been performed for the prepared concrete bunkers; the first one was in-lab compression tests for the cube samples of the prototypes concrete inside the laboratory and the second one was outdoor field shouting tests for the prepared concrete bunker prototypes using 12.7 mm gun fire bullets and a shooting from a distance of 100m targeting. Concrete compression laboratory tests have been conducted for 7,21and 28days aged concrete prototype bunkers while the depth, length and the diameter of the cracks and punching of the bullet hitting locations on the targeted prototype concrete bunker were measured. The results of this research reveals that adding alum along either in 15mg/l or 10 mg/ l doses in the three aged concrete 7,21,and 28 days will affect inversly on the concrete compaction strength by a (1% – 8%) while adding the other mensioned doses (polyelectrolyte along with different doses 10mg/l or 15 mg/l and a hybird doses of alum 10mg/l mixed with polyelectrolite 10mg/l ,will help in increasing the concrete compression strength of the concrete by 3.5% to 12%. Through out the tests its clearly appeared that the optimum coagulant in increasing the capacity of the concrete is polyelectrolyte and with a dosage of 15mg/l and it helps to increase the capacity of the concrete to 9% at 7days , 11.5 % at 21days and 13% at 28days from the age of the concrete .The results showed that the penetration depth for all the seven concrete bunker prototypes, evaluates each prototype performance via their penetration depths, because the penetration depth of the bullet is the most important variable in selecting the best performance concrete bunker prototype among all of them. The results also showed that the minimum penetration was 1.7cm of polyelectrolyte used coagulant prototype of 15mg/L, and the maximum ratio about 2.2cm. The maximum destroyed diameter during the field bullet shooting test resulting that the highest value of maximum destroyed diameter was 20cm with polyelectrolyte used coagulant prototype of 10 mg/L and the lowest one was 10cm while using polyelectrolyte coagulant as admixture of 15 mg/l dosage.

Fe(II)-regulated moderate pre-oxidation of Microcystis aeruginosa and formation of size-controlled algae flocs for efficient flotation of algae cell and organic matter

The coagulation/flocculation/flotation (C/F/F) process is becoming a popular method for algae-laden water treatment. However, the efficiency of flotation is highly dependent on the ability of the preceding coagulation/flocculation process to form flocculated algae flocs. This study aims to improve the Microcystis aeruginosa flotation efficiency from algae cell and organic matter aspects by applying Fe(II)-regulated pretreatment enhanced Al coagulation process. The ability of the C/F/F process to remove cyanobacterial cells can be enhanced from 8% to 99% at a Fe(II) dose of 30 μM. The Al dose needed can be reduced by more than half while achieving successful flotation. The introduced Fe(II) after KMnO4 can not only realize moderate pre-oxidation of cyanobacterial cells, but also form in-situ Fe(III). The DOC value can also be decreased significantly due to the formation of in-situ Fe(III), which is more efficient in dissolved organic matter (DOM) removal compared with pre-formed Fe(III). In addition, the gradually hydrolyzed in-situ Fe(III) can facilitate the hydrolysis of Al as a dual-coagulant and promote the clustering and cross-linking of Al hydrolyzates, which can enhance the formation of size-controlled algae flocs. Finally, the size-controlled algae flocs can be effectively floated by the bubbles released in the flotation process due to the efficient collision and attachment between flocs and bubbles. Therefore, the efficient flotation of algae cell and organic matter can be realized by the Fe(II) regulated moderate pre-oxidation of M. aeruginosa and formation of size-controlled algae flocs.

An advanced pretreatment strategy involving hydrodynamic and acoustic cavitation along with alum coagulation for the mineralization and biodegradability enhancement of tannery waste effluent

In the present study, coagulation followed by cavitation was studied as a pretreatment tool for tannery waste effluent (TWE) with the aim of reducing its COD, TOC, TSS etc. and enhancing its biodegradability to make it suitable for anaerobic digestion. Initially, coagulation was applied to TWE using alum as a coagulant. The residual pH of treated effluent was found to be around pH of 4.5 where maximum COD and TSS reduction was achieved. In order to enhance the efficiency of pretreatment process, coagulated tannery waste effluent (CTWE) was further subjected to hydrodynamic cavitation (HC) and ultrasonication (US). In case of HC, effect of process parameters such as inlet pressure and dilution on the treatment of CTWE was initially investigated. Lower operating pressure (5 bar) was more favorable for the treatment of CTWE using HC in order to enhance the biodegradability index (BI) from 0.14 to 0.57 in 120 min. The CTWE samples when subjected to 50% dilution, HC pretreatment exhibited higher percentage and quantum reduction in TOC and COD. On the other hand, pretreatment of TWE using coagulation followed by US demonstrated that BI of effluent was enhanced from 0.10 to 0.41 in 150 min. Energy efficiency evaluation for all processes at their optimized conditions was done based on the actual amount of COD reduced per unit energy delivered to the system. Coagulation followed by HC for the pretreatment of TWE was found to be six times more energy efficient as compared to coagulation followed by US.

Characterization and removal of natural organic matter from slow sand filter effluent followed by alum coagulation

Characterization and removal of natural organic matter, which is contained in the effluent of slowsand filters, was observed by alum coagulation under various dosages. In addition to non-purgedable dissolved organic carbon (NPDOC), trihalomethanes formation potential (THMFP) and haloacetic acid formation potential (HAAFP) measurement, high-performance size-exclusion chromatography (HPSEC) with ultraviolet/visible and dissolved organic carbon (DOC) detectors was used to characterize the various organic fractions contained in the water before and after coagulation. The results show that alum coagulation could effectively remove hydrophobic aromatic, which forms mainly humic substances. The reduction in THMFP was found to be higher than that of NPDOC and HAAFP under specific alum dosage, and the former was also found to be proportional to the corresponding reduction in the area of hydrophobic aromatic fraction, mostly humic subtances, as obtained from HPSEC chromatogram with peak-fitting.

Possibility of utilizing natural coagulants (Trigonella foenum-graecum and Astragalus gossypinus) along with alum for the removal of turbidity

Water, especially drinking water, might need to be treated before being utilized. Coagulants play a significant role in water treatment. In spite of having adverse effects on human health, aluminum sulfate, alum and other chemical coagulants are commonly used in coagulation processes. Utilization of natural and herbal materials such as quince seeds, fleawort, tragacanth, starch and yeast as coagulant aids has been experimentally investigated in this study. The aims of the present paper are: (1) to determine the optimal dose of Trigonella foenum-graecum (fenugreek) and Astragalus gossypinus (tragacanth) seeds as coagulant aids along with alum for the coagulation of raw water from Minab water treatment plant) located 7 km away from Bandar Abbas–Minab road at the east of Bandar Abbas in Iran, with a total area of 11.5 ha) and (2) to study their influence on reducing the water turbidity at a pilot scale. According to the obtained results, the optimum amount of alum (without additives) was calculated as 35 mg/L for water with the initial turbidity of 70–75 NTU, as the average turbidity interval. Using A. gossypinus and T. foenum-graecum seeds as coagulant aids, the optimum amount of alum reached 22 mg/L. The performance of A. gossypinus, as a coagulant aid, was much better in low concentrations. It was used in doses of 0.25, 1 and 2 mg/L along with 20, 22 and 28 mg/L of alum for low, intermediate and high turbidity levels (28, 70 and 120 NTU) and led to turbidity removal percentages of 85, 94.5 and 96.4, respectively. The optimum amounts of T. foenum-graecum seeds for the three mentioned turbidity levels were calculated as 1, 2 and 4 mg/L. The turbidity removal percentages of 91.5, 95.7 and 97.8 were obtained using the mentioned amounts of T. foenum-graecum seeds along with 20, 22 and 25 mg/L of alum, respectively. Similar results were obtained by using both additives along with alum.

Fate of nanoparticles during alum and ferric coagulation monitored using single particle ICP-MS

In this study, aluminum sulfate, ferric sulfate, ferric chloride, and poly(diallyldimethylammonium chloride) (pDADMAC) coagulation removal of citrate-stabilized silver and gold nanoparticles (NPs) and uncoated titanium dioxide, cerium dioxide, and zinc oxide NPs was investigated using a single particle (SP) ICP-MS direct monitoring technique. Zone 2 (charge neutralization) coagulation was performed in river water and more commonly used Zone 4 (sweep floc) coagulation was performed in both river and lake water with environmentally relevant concentrations of selected NPs added. SP-ICP-MS was used to detect NP and dissolved species, characterize the size distribution, and quantify particle concentration as well as dissolved species before and after treatments. Other parameters including pH, dissolved organic carbon, turbidity, and UV254 absorbance were monitored to characterize treatment efficiency. Charge neutralization (Zone 2) coagulation resulted in 48–85% removal of citrate-stabilized NPs and 90–99% removal of uncoated NPs from river water. Sweep floc (Zone 4) coagulation in river water resulted in 36–94% removal of citrate-stabilized NPs and 91–99% removal of uncoated NPs both with and without polymer addition. Zone 4 coagulation conditions in lake water resulted in 77–98% removal of citrate-stabilized NPs and 59–96% removal of uncoated NPs without polymer. These results indicate that NP removal depends on NP surface and stability, the nature of the source water, and the coagulant type and approach.

A sequential treatment of intermediate tropical landfill leachate using a sequencing batch reactor (SBR) and coagulation

The increase in landfill leachate generation is due to the increase of municipal solid waste (MSW) as global development continues. Landfill leachate has constantly been the most challenging issue in MSW management as it contains high amount of organic and inorganic compounds that might cause pollution to water resources. Biologically treated landfill leachate often fails to fulfill the regulatory discharge standards. Thus, to prevent environmental pollution, many landfill leachate treatment plants involve multiple stages treatment process. The Papan Landfill in Perak, Malaysia currently has no proper leachate treatment system. In the current study, sequential treatment via sequencing batch reactor (SBR) followed by coagulation was used to treat chemical oxygen demand (COD), ammoniacal nitrogen (NH3-N), total suspended solids (TSS), and colour from raw landfill leachate. SBR optimum aeration rate, L/min, optimal pH and dosage (g/L) of Alum for coagulation as a post-treatment were determined. The two-step sequential treatment by SBR followed by coagulation (Alum) achieved a removal efficiency of 84.89%, 94.25%, 91.82% and 85.81% for COD, NH3-N, TSS and colour, respectively. Moreover, the two-stage treatment process achieved 95.0% 95.0%, 95.3%, 100.0%, 87.2%, 62.9%, 50.0%, 41.3%, 41.2, 34.8, and 22.9 removals of Cadmium, Lead, Copper, Selenium, Barium, Iron, Silver, Nickel, Zinc, Arsenic, and Manganese, respectively.