Specific H2S Release from Thiosulfate Promoted by UV Irradiation for Removal of Arsenic and Heavy Metals from Strongly Acidic Wastewater

Water is fundamental to the survival of living beings. It registers every impact and can function as an indicator of environmental stressors. Our objective in the current study was to assess the sanitary conditions of the waters in the Açude, Maria Lucinda and Santa Rosa streams. This was done by checking pH, running quantitative analyses of heavy metals and testing for total coliforms. The effect of ultraviolet (UV) rays on samples positive for coliforms was evaluated. The average pH of the streams ranged between 4 and 7 and changed between drought and rainy season conditions. Chromium and nickel values were above those permitted by the Brazilian National Council on the Environment, CONAMA. In the dry season, zinc values were above those established by CONAMA for waterbodies of Classes 1 and 2. Thermotolerant coliforms were present in all samples collected and above permitted values. After exposing the bacteria to UV light, it was noted that UV irradiation was unable to decrease the bacteria count. Ninety residents who use stream water were interviewed: 24% of interviewees said they use the waters of the Açude and Mary Lucinda streams and along the Santa Rosa stream, 95% of inhabitants said they use the water.

Download Full-text

Removal of Arsenic from Aqueous Solution by Photocatalytic UV Irradiation

Research Journal of Environmental Sciences ◽

10.3923/rjes.2014.399.404 ◽

2014 ◽

Vol 8 (7) ◽

pp. 399-404 ◽

Cited By ~ 1

Author(s):

Mahsa Jahangiri-

Keyword(s):

Aqueous Solution ◽

Uv Irradiation ◽

Removal Of Arsenic

Download Full-text

Pilot-Scale Removal of Arsenic and Heavy Metals from Mining Wastewater Using Adsorption Combined with Constructed Wetland

Minerals ◽

10.3390/min9060379 ◽

2019 ◽

Vol 9 (6) ◽

pp. 379 ◽

Cited By ~ 6

Author(s):

Ha Nguyen ◽

Bien Nguyen ◽

Thuy Duong ◽

Anh Bui ◽

Hang Nguyen ◽

...

Keyword(s):

Heavy Metals ◽

Constructed Wetland ◽

Pilot Scale ◽

Common Reed ◽

X Ray Diffraction ◽

Combined System ◽

Constant Flow Rate ◽

Mining Wastewater ◽

Scale Experiment ◽

Removal Of Arsenic

This study was conducted to assess the removal of arsenic (As) and heavy metals from mining wastewater by the combination of adsorption, using modified iron-ore drainage sludge, and horizontal-subsurface-flow constructed wetland with common reed (Phragmites australis). The pilot-scale experiment with a constant flow rate of 5 m3/day was operated for four months using real wastewater from a Pb–Zn mine in northern Vietnam. Atomic absorption spectroscopy was used for elemental analysis in wastewater and plant. X-ray diffraction (XRD), surface charge measurements (by a particle charge detector (PCD)), Fourier-transform infrared (FTIR), and surface area Brunauer–Emmet–Teller (BET) measurements were performed to determine the characteristics of the adsorbent. The results showed that the average removals of As, Mn, Cd, Zn, and Pb by the combined system with limestone substrate during four months were 80.3%, 96.9%, 79.6%, 52.9%, and 38.7%, respectively. The use of another constructed wetland substrate, laterite, demonstrated better removal efficiency of As than limestone. The concentrations of As and heavy metals in the effluent were lower than the limits established by the QCVN 40:2011/BTNMT for industrial wastewater, which indicated the feasibility of combining adsorption and constructed wetland for the treatment of mining wastewater.

Download Full-text

Characterization of iron and steelmaking wet dust for arsenic remove in wastewaters

MRS Proceedings ◽

10.1557/opl.2012.408 ◽

2012 ◽

Vol 1380 ◽

Cited By ~ 1

Author(s):

V. Narvaez-García ◽

A. Martínez-Luevanos ◽

F. Carrillo-Pedroza ◽

M. Soria-Aguilar ◽

M. Guajardo-Castillo ◽

...

Keyword(s):

Heavy Metals ◽

Water Treatment ◽

Specific Area ◽

Process Efficiency ◽

Environmental Applications ◽

Total Arsenic ◽

Initial Concentration ◽

Removal Of Heavy Metals ◽

Removal Of Arsenic

ABSTRACTDust originated from the iron and steelmaking containing undesirable compounds are not completely recycled because affects the process efficiency. These types of dust represents an economical lost as a consequence of values contents. However, dust have been characterized physically and chemically in order to study their potential environmental applications, as the removal of arsenic in wastewater. The results shows that dust have a superficial specific area between 16 and 20 m2/g, values considered high, typical of a material with adsorbent properties. Representative results of different tests adsorption of arsenic in the material described indicate that it is possible to reduce the arsenic levels in up to 95% from an initial concentration of 1 mg/L of total arsenic. The results indicate that the iron and steelmaking wet dust may represent a new option as material for the removal of heavy metals in water treatment.

Download Full-text

Industrial Wastewater Treatment by Nanofiltration—A Case Study on the Anodizing Industry

Membranes ◽

10.3390/membranes10050085 ◽

2020 ◽

Vol 10 (5) ◽

pp. 85

Author(s):

Aamer Ali ◽

Maria C. Nymann ◽

Morten L. Christensen ◽

Cejna A. Quist-Jensen

Keyword(s):

Heavy Metals ◽

Wastewater Treatment ◽

Industrial Wastewater ◽

Pure Water ◽

High Permeability ◽

High Quality ◽

Ion Rejection ◽

High Concentrations ◽

Acidic Wastewater

The anodizing industry generates several alkaline and acidic wastewater streams often with high concentrations of heavy metals. In this study, nanofiltration (NF) was used to treat wastewater from individual baths, i.e., wastewater from color rinse, alkaline pickling rinse, acidic pickling rinse and anodizing rinse, as well as a mixture of all the wastewater streams. The experiments were carried out by using a commercial membrane (NF99HF) exhibiting pure water permeability of 10 L/(m2·h·bar). For all wastewater streams except one, pH was adjusted to bring it within the recommended pH limits of the membrane, whereby part of the heavy metals precipitated and was removed. The NF of the color rinse offered high-quality permeate (heavy metals below detection limit) and high permeability (9 L/(m2·h·bar)), whereas the nanofiltration of the alkaline pickling rinse exhibited no permeability. The NF of the acidic pickling rinse showed a permeability of 3.1–4.1 L/(m2·h·bar), but low ion rejection (7–13%). NF of the neutralized mixed wastewater, after the removal of precipitate, produced high-quality permeate with a stable permeability of 1 L/(m2·h·bar). Treatment of the mixed wastewater is therefore the best option if the water has to be discharged. If the water has to be reused, the permeate conductivity in the color rinse and anodizing rinse baths have been reduced significantly, so the treatment of these streams may then be a better option.

Download Full-text