Starch-based flocculant outperformed aluminium sulfate hydrate and polyaluminium chloride through effective bridging for harvesting acicular microalga Ankistrodesmus

2018 ◽  
Vol 29 ◽  
pp. 343-353 ◽  
Author(s):  
Sook Yan Choy ◽  
Krishna Murthy Nagendra Prasad ◽  
Ta Yeong Wu ◽  
Mavinakere Eshwaraiah Raghunandan ◽  
Siew-Moi Phang ◽  
...  
2001 ◽  
Vol 44 (10) ◽  
pp. 231-236 ◽  
Author(s):  
J. Gregory ◽  
V. Dupont

Hydrolyzing coagulants are extensively used in water and wastewater treatment, often under conditions where hydroxide precipitation is important, giving “sweep flocculation”. Pre-hydrolyzed coagulants, such as polyaluminium chloride (PACl) are also widely used and have several advantages over traditional additives, such as aluminium sulfate. Their action is usually discussed in terms of cationic species and charge neutralization. However, precipitation may also be important and this aspect has not been considered in detail. The present work has compared the action of alum and three commercial PACl products on model clay suspensions. The conventional jar test procedure has been used, along with measurements of settled floc volume and dynamic monitoring of floc formation and break-up by an optical technique. The latter method gives very useful information on the nature of the flocs produced and their response to different shear conditions. It is clear from the results that the PACl products form larger and stronger flocs than alum. With all coagulants floc breakage appears to be essentially irreversible. Sediment volumes are slightly lower for flocs produced by PACl than by alum, but the value is proportional to the dosage in all cases.


Author(s):  
Le Thi Xuan Thuy ◽  
Le Thi Suong

This article presented the results of color treament ability of Tarcon Blue 2BLN dye with some flocculation chemicals such as PGa21Ca, polyaluminium chloride (PAC), iron (II) sulfate heptahydrate (FeSO4.7H2O) and aluminium sulfate octadecahydrate (Al2(SO4)3.18H2O). Our results showed that conditions for treatment the color to reach column B, QCVN 13: 2015 / BTNMT (national technical regulation on textile and dying industry) by different flocculation chemicals were the same exposure time (10 minutes), sedimentation time (30 minutes), but different in parameters of concentration (% mass), stirring speed and pH. Specifically: PGa21Ca (0.02%), PAC (0.01%), aluminium sulfate octadecahydrate (0.003%) can handle color at the initial pH of the solution (pH = 6), with the stirring speed corresponding to each flocculation chemical at 120 rpm, 45 rpm and 45 rpm respectively. In contrast, with iron (II) sulfate heptahydrate (0.02%), only the color treatment reaches column B, QCVN 13: 2015 / BTNMT when the pH of the wastewater raises to 10 and stirring speed is 120 rpm. Compared with PAC, aluminium sulfate octadecahydrate and iron (II) sulfate heptahydrate, PGa21Ca has the advantage of contributing to raise the pH value in the acid solution, which reduces the pH in the base environment, and not changing the pH when the concentration of PGa21Ca increases. Test results on actual wastewater samples taken from Hoa Khanh Danang Textile Joint Stock Company (DANATEX) showed that the ability of treating color of these chemicals on actual wastewater samples is lower than the ability on water samples blended with Tarcon Blue 2BLN dye.


2008 ◽  
Vol 59 (9) ◽  
Author(s):  
Elena Cical ◽  
Gabriela Oprea ◽  
Cristina Mihali ◽  
Laura Ardelean ◽  
Georgeta Burtica ◽  
...  

Polyaluminium chloride is a new coagulation reagent recommended for water treatment. This paper presents a study regarding water treatment from the storage lake St�mtori � Firiza with this new coagulation reagent in comparison with the classic method currently applied. The classic method uses cake of alum (aluminium sulfate) and hydrated lime. In the case of atypical waters having low temperatures, low alkalinity and variable turbidity, the classic method has poor results. The main purpose of the experimental studies is to establish the adequate doses of coagulation reagent for obtaining drinking water according to present legislations.


Author(s):  
G. Samburskii ◽  
O. Ustinova ◽  
Svetlana, Leont’eva

Распространенным технологическим приемом удаления из воды грубодисперсных примесей, находящихся во взвешенном состоянии, а также коллоидных органических загрязнений, присутствующих в растворенном виде, является процесс коагуляции. Эффективными коагулянтами для систем с водной дисперсионной средой являются соли поливалентных металлов. Цель работы заключалась в создании нового государственного стандарта, предназначенного для обеспечения единообразной оценки качества коагулянтов. Рассмотрена область применения коагулянтов в процессе водоподготовки и проведен их сравнительный анализ. Показана необходимость унификации в области процессов контроля качества коагулянтов. Сформулированы общие требования к контролю качества полиоксихлорида алюминия. Представлен разработанный и утвержденный новый национальный стандарт ГОСТ Р 58580-2019 Полиоксихлорид алюминия. Технические условия , который учитывает требования санитарного законодательства, технического регулирования, безопасности процессов производства и транспортировки полиоксихлорида алюминия.Coagulation process has been a widespread process technology for removing coarse suspended impurities from water, as well as colloidal organic contaminants present in dissolved form. Polyvalent metal salts are effective coagulants for the systems with aqueous disperse medium. The purpose of the work was developing a new state standard to provide for a uniform assessment of the quality of coagulants. The scope of coagulants in the process of water treatment is considered and their comparative analysis is carried out. The general requirements to the control of polyaluminium chloride quality are formulated. The developed and approved new national standard GOST R 58580-2019 Polyaluminium chloride. Technical conditions is presented that takes into account the requirements of sanitary legislation, technical regulation, safety of the processes of production and transportation of polyaluminium chloride.


1987 ◽  
Vol 19 (8) ◽  
pp. 139-145
Author(s):  
G. Castillo ◽  
A. Ortega

The reutilization in agriculture of the sludge produced in the chemical treatment of sewage is investigated. Aluminium sulfate (50 mg/l) and sodium hydroxide (50 and 200 mg/l) are added to domestic sewage allowing it to settle and eliminating floating materials. Three kinds of raw chemical sludge are digested and dried. Their sanitary quality is determined by two bacterial indicators (total and fecal coliforms) and one viral indicator (E. coli bacteriophage) and the fertilizing capability of digested and dry sludge by sowing leguminous crops (Phaseolus spp ) in soil with 11 tons/ha sludge application rate. Digested and dried sludge from conventional treatment in equal conditions to those of chemical sludge is used as reference. Sanitary quality results show that raw and digested chemical sludge are not recommended for use in agriculture due to their high microbiological contamination. Dry sludge could be considered for this purpose due to its low fecal organisms content. However the development of leguminous crops in soil with dry aluminium sludge application shows no seed germination. The results of leguminous growth in digested sludge of sodium hydroxide (200 mg/l) justify an additional treatment to adequate its sanitary quality for use in agriculture.


2019 ◽  
Vol 4 (1) ◽  
pp. 15
Author(s):  
Ariyetti Ariyetti ◽  
Muhammad Nasir ◽  
Safni Safni ◽  
Syukri Darajat

<p><em>Metil merah merupakan salah satu zat warna golongan azo yang sering digunakan dalam industri dan laboratorium. Penggunaan metil merah dapat menimbulkan efek terhadap kesehatan dan lingkungan. Oleh sebab itu dilakukan metode fotodegradasi dengan menggunakan semikonduktor dan radiasi sinar tampak. Semikonduktor yang digunakan yaitu berbahan dasar tembaga sulfat hidrat dan perak nitrat. Prekusor tembaga sulfat hidrat dibuat dari pengolahan limbah logam tembaga hasil pemotongan tembaga yang ada di bengkel Lembaga Ilmu Pengetahuan Indonesia (LIPI) Bandung. Bahan semikonduktor juga memiliki kemampuan dalam menghambat pertumbuhan bakteri. Hasil optimum yang didapatkan dalam proses fotodegradasi dan antibakteri merupakan gabungan antara kedua prekusor tembaga sulfat hidrat dan perak nitrat dengan bantuan penyinaran. Kemampuan dalam menghambat pertumbuhan bakteri didapatkan persentase kematian 100 % untuk masing-masing bakteri, yaitu Escherichia coli dan Staphylococcus aureus. Aktifitas fotokatalitiknya dengan konsentrasi semikonduktor 10 ppm untuk mendegradasi zat warna metil merah 5 ppm, selama 23 jam, dimana persentase degradasi yang didapatkan dengan penyinaran lebih tinggi dibandingkan dengan tanpa penyinaran. Pengaruh pH larutan terhadap degradasi metil merah yaitu optimum pada pH 12 (basa).</em></p><p><em><br /></em></p><p><em>Methyl red is one of the azo group dyes that is often used in industry and laboratories. The use of methyl red can have an effect on health and the environment. Therefore photodegradation method is done by using semiconductor and visible light radiation. The semiconductor used is based on copper sulfate hydrate and silver nitrate. The copper sulphate hydrate precursor is made from the processing of copper-cut copper metal waste in the workshop of the Indonesian Institute of Sciences (LIPI) in Bandung. Semiconductor materials also have the ability to inhibit bacterial growth. The optimum results obtained in the photodegradation and antibacterial process are a combination of both copper sulfate hydrate precursor and silver nitrate with the help of irradiation. The ability to inhibit bacterial growth obtained 100% mortality for each bacterium, namely Escherichia coli and Staphylococcus aureus. Photocatalytic activity with 10 ppm semiconductor concentration to degrade methyl red dye 5 ppm, for 23 hours, where the percentage of degradation obtained by irradiation is higher than without irradiation. The effect of pH of the solution on the degradation of methyl red is optimum at pH 12 (base).</em></p>


1998 ◽  
Vol 63 (4) ◽  
pp. 507-514
Author(s):  
Madan L. Parmar ◽  
Ch. V. Nageshwara Rao ◽  
Suresh Chand Attri

Partial molar volumes of ammonium aluminium sulfate and potassium aluminium sulfate in DMF-water mixtures (5-20 wt.% of DMF) have been determined from solution density measurements at various temperatures and electrolyte concentrations. The data were evaluated by using Masson equation and the obtained parameters were interpreted in terms of ion-solvent and ion-ion interactions. Both electrolytes have been found to act as the structure makers/promotors in DMF-water systems.


Water ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 1947
Author(s):  
Ling Su ◽  
Chen Zhong ◽  
Lei Gan ◽  
Xiaolin He ◽  
Jinlei Yu ◽  
...  

The application of lanthanum modified bentonite (Phoslock®) and polyaluminium chloride (PAC) is popular in the restoration of European temperate lakes; however, the effects of the application on the concentrations of phosphorus (P) in both the water and the sediments have been poorly evaluated to date. We studied the effects of the application of Phoslock® + PAC on the concentrations of total phosphorus (TP), particulate phosphorus (PP), soluble reactive phosphorus (SRP), total suspended solids (TSS) and chlorophyll a (Chla) in the water, and different P forms in the sediments, in an isolated part of Lake Yanglan. The results showed that the concentrations of TP, PP, SRP, TSS and Chla decreased significantly after the addition of Phoslock® + PAC. Moreover, the concentrations of labile-P, reductant-soluble-P and organic-P in the sediments were also significantly decreased after the Phoslock® + PAC application. However, the concentrations of both the stable apatite-P and residual-P in the sediments after application of Phoslock® + PAC were much higher than the pre-addition values, while the concentrations of metal-oxide-P did not differ significantly between the pre- and post- application conditions. Our findings imply that the combined application of Phoslock® and PAC can be used in the restoration of subtropical shallow lakes, to reduce the concentrations of P in the water and suppress the release of P from the sediments.


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