Advances in Chemical Conditioning of Residual Activated Sludge in China

Liang, Yankai; Wang, Rui; Sun, Weibang; Sun, Yongjun

doi:10.3390/w15020345

Cited by 9 publications

(3 citation statements)

References 53 publications

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“…The experimental values of this test are plotted as given in figure (7). The highest percentage reduction in turbidity of 97.8% is satisfied when using 2.4 g/l gel concentration.…”

Section: Using 15 G/l Clay Suspensionmentioning

confidence: 98%

“…Coagulation-flocculation is a common process used to remove various contaminants such as suspended solids, organic and inorganic materials. In this process, a coagulating material is added to the contaminated water to destabilize colloidal materials allowing the suspended particles to agglomerate to form larger settleable flocs [7]. However, one of the disadvantages of this process is that traces of the coagulant remain in the treated water, which negatively affects human health and may cause neurotoxicity if a chemical reagent is used [8].…”

Section: Introductionmentioning

confidence: 99%

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Reduction of water turbidity with bio-flocculent: Use of Aloe Vera Gel

Ismaeel,

Tayeb

2024

International Journal of Industry and Sustainable Development

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Presence of turbidity in water reduces its quality and makes it unsuitable for different uses. Turbidity is a result of the presence of negatively-charged, fine particles in the water; causing it being polluted. It is removed by adding a coagulant/ flocculent to the polluted water to neutralize the negative charges on the suspended particles. This step is known as coagulation and is followed by a flocculation step when the uncharged particles form larger flocs capable of settling. Chemical coagulants proved to have many dangerous effects on human health and negative effects on the environment. Thus, the use of biomaterials has become an interesting alternative. The present study is set out to use Aloe Vera Gel (AVG) as an example of a natural coagulant for treating of turbid water. Experiments are conducted on a suspension of clay in water. The variables studied are: coagulant dose, clay concentration, mixing time, hydration of clay and particle size of clay. The highest percentage reduction in turbidity (97.73%) was achieved by clay suspensions of low concentration (20g/l), gel dose (2g/l) after 125 minutes. The recorded value for residual turbidity was 18.1 NTU. Also, clay suspension with 15 g/L concentration gives the lowest value of residual turbidity 21.9 NTU after 125 minutes using 2.4 g/L of gel concentration with percent reduction 97.08%. Hydration of clay particles resulted in a higher percentage reduction in turbidity (60.9% for the hydrated sample and 30.8% for the un-hydrated sample, after 5 minutes of settling). The combination of 10 minutes rapid mixing and 15 minutes of slow mixing gave the best results compared to other combinations tested. Thus, the results of the current research showed that AVG can serve as a promising bio-coagulant with high efficiency in removing turbidity from polluted water.

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“…The experimental values of this test are plotted as given in figure (7). The highest percentage reduction in turbidity of 97.8% is satisfied when using 2.4 g/l gel concentration.…”

Section: Using 15 G/l Clay Suspensionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

Reduction of water turbidity with bio-flocculent: Use of Aloe Vera Gel

Ismaeel,

Tayeb

2024

International Journal of Industry and Sustainable Development

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“…At this time, the traditional way of disposal of sewage sludge in countries such as Serbia, Malta and Ukraine is accumulation on special sites [15,16]. The low level of sewage sludge utilization in Ukraine is mainly due to imperfect legislation and outdated equipment and technologies for wastewater treatment [17,18]. According to the state standard of Ukraine (DSTU 7369:2013), municipal sewage sludge (MSS) can be applied to arable lands with minimum rates of 10 t/ha for three consecutive years.…”

Section: Introductionmentioning

confidence: 99%

Production of Sweet Sorghum Bio-Feedstock on Technosol Using Municipal Sewage Sludge Treated with Flocculant, in Ukraine

et al. 2023

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This paper presents the influence of sewage sludge (SS) on the biometric parameters, absorption of mineral elements and thermal characteristics of sweet sorghum (Sorghum bicolor L.) grown on Technosol. Two types of sewage sludge were used: unmodified and modified with DAMET flocculant. Each type of sludge was applied in three doses (expressed as dry matter basis, DM): 20 t DM/ha, 40 t DM/ha and 60 t DM/ha, respectively. The yield of fresh biomass depended on the dose of sewage sludge: it increased by 14.5–41% and reached 104.6 t/ha after application of the sewage sludge with flocculant at a maximum rate of 60 t/ha. Sorghum biomass actively absorbs nutrients from the soil. Nitrogen was absorbed more actively; depending on the type and dose of sewage sludge application, its content in biomass increased from 12–40% (dose of 20 t/ha) to 80–112% (dose of 60 t/ha). By content in sorghum biomass, essential elements can be arranged in descending order as follows: Fe → Mn → Zn → Cu. Sorghum shows a low ability to accumulate some heavy metals in aboveground biomass. Despite the fact that large doses of sewage sludge contributed to an increase in the content of nickel, cadmium and lead in the substrate by 1.8–5.6 times, the ratio of the content of these elements in plants to the content in the substrate remained low. Sewage sludge affects the process of thermal degradation of sorghum biomass. The decomposition of the main components occurs at lower temperatures, and, as a rule, at higher rates. Sewage sludge (especially with flocculant) contributes to a more complete combustion of biomass. The results showed that sewage sludge with flocculant at a dose of 40 t/ha is the most optimal fertilizer option for growing sweet sorghum on such Technosols as loess-like loam.

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