scholarly journals Utilization of artificial recharged effluent for irrigation: pollutants' removal and risk assessment

2016 ◽  
Vol 7 (1) ◽  
pp. 77-87
Author(s):  
Liangliang Wei ◽  
Kena Qin ◽  
Qingliang Zhao ◽  
Kun Wang ◽  
Felix Tetteh Kabutey ◽  
...  
Keyword(s):  
Risk Assessment ◽  
Reclaimed Water ◽  
Carcinogenic Risk ◽  
Secondary Effluent ◽  
Soil Aquifer Treatment ◽  
Source Water ◽  
Pak Choi ◽  
Order Of Magnitude ◽  
Pollutants Removal ◽  
Pre Treatment

The reclaimed water from soil aquifer treatment (SAT) column was reused for irrigation as the source water, pollutants' removal and health risk assessment was analyzed via the comparison with secondary and tertiary effluents. The effect of the SAT pre-treatment on the qualities and growth of different crops (Lachca sativa – lettuce, Brasica rapa var chinensis – pak choi, Cucumis sativus – cucumber, Brassica oleracea – cabbage, and Zea mays – maize) were evaluated. Experimental results demonstrated that the tertiary and SAT treatments had no significant effect on the crop qualities, and could efficiently decrease the accumulation of heavy metals (especially for SAT pre-treatment). Moreover, the carcinogenic risk of the chemical carcinogens for the 1.5 m SAT effluent irrigation declined roughly an order of magnitude as compared with the secondary effluent, and three to four orders of magnitude decreasing of the virus risk. These findings are significant for the safe and cheap reuse of secondary effluent for irrigation purposes.

Utilization of artificial recharged effluent as makeup water for industrial cooling system: corrosion and scaling

2016 ◽  
Vol 73 (10) ◽  
pp. 2559-2569 ◽  
Author(s):  
Liangliang Wei ◽  
Kena Qin ◽  
Qingliang Zhao ◽  
Daniel R. Noguera ◽  
Ming Xin ◽  
...  
Keyword(s):  
Wastewater Treatment Plants ◽  
Cooling System ◽  
Cooling Water ◽  
Oxygen Demand ◽  
Design Criterion ◽  
Secondary Effluent ◽  
Soil Aquifer Treatment ◽  
Makeup Water ◽  
Circulating Cooling Water ◽  
Pre Treatment

The secondary effluent from wastewater treatment plants was reused for industrial cooling water after pre-treatment with a laboratory-scale soil aquifer treatment (SAT) system. Up to a 95.3% removal efficiency for suspended solids (SS), 51.4% for chemical oxygen demand (COD), 32.1% for Cl− and 30.0% SO42− were observed for the recharged secondary effluent after the SAT operation, which is essential for controlling scaling and corrosion during the cooling process. As compared to the secondary effluent, the reuse of the 1.5 m depth SAT effluent decreased the corrosion by 75.0%, in addition to a 55.1% decline of the scales/biofouling formation (with a compacted structure). The experimental results can satisfy the Chinese criterion of Design Criterion of the Industrial Circulating Cooling Water Treatment (GB 50050-95), and was more efficient than tertiary effluent which coagulated with ferric chloride. In addition, chemical structure of the scales/biofouling obtained from the cooling system was analyzed.

scholarly journals Options and limitations of hydrogen peroxide addition to enhance radical formation during ozonation of secondary effluents

2014 ◽  
Vol 5 (1) ◽  
pp. 8-16 ◽  
Author(s):  
U. Hübner ◽  
I. Zucker ◽  
M. Jekel
Keyword(s):  
Hydrogen Peroxide ◽  
Treatment Options ◽  
Radical Formation ◽  
Secondary Effluent ◽  
Soil Aquifer Treatment ◽  
Batch Experiments ◽  
Efficient Removal ◽  
Potable Reuse ◽  
Secondary Effluents ◽  
Pre Treatment

The oxidation of secondary effluent with ozone and O3/H2O2 (peroxone) was evaluated in batch experiments as pre-treatment for soil aquifer treatment for non-potable reuse purposes. The addition of hydrogen peroxide improved the reduction of ozone-resistant compounds with an optimized radical formation at 0.5 mol H2O2/mol O3. However, the improvement of radical formation was shown to be limited to approximately 30–40% independent from ozone dosage. Also a preozonation step did not accelerate efficiency of subsequent peroxone treatment. Thus, other treatment options, such as an increase of ozone dosages, need to be considered for more efficient removal of ozone-resistant compounds. However, the peroxone process might still be a promising option for oxidation of bromide containing effluents, since a reduction of bromate formation can allow the application of higher ozone dosages.

scholarly journals Risk assessment of Ni, Cr, and Si release from alkaline minerals during enhanced weathering

2020 ◽  
Vol 5 (1) ◽  
pp. 166-175
Author(s):  
Fatima Haque ◽  
Yi Wai Chiang ◽  
Rafael M. Santos
Keyword(s):  
Risk Assessment ◽  
Environmental Protection Agency ◽  
Hazard Index ◽  
Carcinogenic Risk ◽  
Contamination Level ◽  
Potential Threat ◽  
Silicate Minerals ◽  
Guideline Value ◽  
Quality Guideline ◽  
Index Value

AbstractCalcium- and magnesium-rich alkaline silicate minerals, when applied to soil, can aid in carbon dioxide sequestration via enhanced weathering. The weathering of these silicate minerals is also associated with the release of heavy metals such as Ni and Cr, depending on the composition of the parent rock, and also labile Si. This paper critically analyses the risk associated with the release of Ni, Cr, and Si from alkaline silicate minerals as a result of enhanced weathering to evaluate its potential to be applied as a soil amendment. Based on the available data in the literature, this study evaluates the soil contamination level and quantifies the risk these elements pose to human health as well as the environment. To assess these potential threat levels, the geoaccumulation index was applied, along with the method recommended by the US Environmental Protection Agency for health risk assessment. The main findings of this study indicate the potential release of Ni, Cr, and Si to exceed the soil quality guideline value. The geochemical index suggests that the analyzed samples are in the class 0–3 and represents sites that lie between uncontaminated zones to highly contaminated zones. The hazard index value for Ni and Cr is greater than unity, which suggests that Ni and Cr release poses a non-carcinogenic risk. The probability of labile Si concentration in the soil to exceed the critical value is found to be 75%.

Carcinogenic Risk Assessment of Complex Mixtures

1989 ◽  
Vol 5 (5) ◽  
pp. 851-867 ◽  
Author(s):  
D. Krewski ◽  
T. Thorslund ◽  
J. Withey
Keyword(s):  
Risk Assessment ◽  
Low Dose ◽  
Synergistic Effects ◽  
Carcinogenic Risk ◽  
Complex Mixtures ◽  
Multiple Exposures ◽  
Polycyclic Aromatic ◽  
Carcinogenic Substances ◽  
Carcinogenic Risk Assessment ◽  
Potential Use

Although procedures for assessing the carcinogenic risks associated with exposure to individual chemicals are relatively well developed, risk assessment methods for mixtures of chemicals are still in the developmental stage. In this paper, we examine the difficulties in assessing the risks of exposure to complex mixtures, with special reference to the potential for synergistic effects among the compo nents of the mixture. Statistical models for describing the joint action of multiple exposures are reviewed, and their implications for low-dose risk assessment are examined. The potential use of pharmacokinetic models to describe the metabolism of mixtures is also considered. Application of these results in regulating mixtures of carcinogenic substances is illustrated using examples involving multiple contaminants in drinking water and polycyclic aromatic hydrocarbons produced from combustion sources.

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