Utilization of ferrous slags as coagulants, filters, adsorbents, neutralizers/stabilizers, catalysts, additives, and bed materials for water and wastewater treatment: A review.

Solid waste is currently produced in substantial amounts by industrial activities. While some are recycled, the majority of them are dumped in landfills. Iron and steel production leaves behind ferrous slag, which must be created organically, managed wisely and scientifically if the sector is to remain more sustainably maintained. Ferrous slag is the term for the solid waste that is produced when raw iron is smelted in ironworks and during the production of steel. Both its specific surface area and porosity are relatively high. Since these industrial waste materials are so easily accessible and offer such serious disposal challenges, the idea of their reuse in water and wastewater treatment systems is an appealing alternative. There are many components such as Fe, Na, Ca, Mg, and silicon found in ferrous slags, which make it an ideal substance for wastewater treatment. This research investigates the potential of ferrous slag as coagulants, filters, adsorbents, neutralizers/stabilizers, supplementary filler material in soil aquifers, and engineered wetland bed media to remove contaminants from water and wastewater. Ferrous slag may provide a substantial environmental risk before or after reuse, so leaching and eco-toxicological investigations are necessary. Some study revealed that the amount of heavy metal ions leached from ferrous slag conforms to industrial norms and is exceedingly safe, hence it may be employed as a new type of inexpensive material to remove contaminants from wastewater. The practical relevance and significance of these aspects are attempted to be analyzed, taking into account all recent advancements in the fields, in order to help in the development of informed decisions about future directions for research and development related to the utilization of ferrous slags for wastewater treatment.

Dose estimation of radioactivity in groundwater of Srinagar City, Northwest Himalaya, employing fluorimetric and scintillation techniques.

The research is a maiden study aimed to assess the radioactivity in groundwater of Srinagar City using uranium and radon as proxies. In this study, 60 water samples were collected from various water sources that include bore wells, hand pumps and lakes of Srinagar City. Among them, 45 samples were taken from groundwater with depths ranging from 6 to - 126 m and the rest of the 15 samples were collected from surface sources like lakes, rivers and tap water. A gamma radiation survey of the area was carried out prior to collection of water samples, using a gamma radiation detector. A scintillation-based detector was utilized to measure radon, while as LED fluorimetry was employed to assess uranium in water samples. The average uranium concentration was found to be 2.63 µg L-1 with a maximum value of 15.28 µg L-1 which is less than the globally accepted permissible level of 30 µg L-1. 222Radon concentration varied from 0.2 to 38.5 Bq L-1 with an average value of 8.9 Bq L-1. The radon concentration in 19 groundwater samples (32% of total sites) exceeded the permissible limits of 11 Bq L-1 set by USEPA. This information could be of vital importance to health professionals in Kashmir who are researching on the incidence of lung cancers in the region given the fact that radon is the second leading cause of lung cancers after smoking worldwide.

A MODEL TO PREDICT 238U IN AQUIFER ROCK BASED ON 222Rn AND 226Ra MEASUREMENT IN GROUNDWATER SAMPLES: A CASE STUDY AT SOUTH BENGALURU CITY, KARNATAKA, INDIA.

Naturally occurring 222Rn and 226Ra concentrations were investigated in groundwater samples collected from different parts of South Bengaluru city using Smart RnDuo monitor developed indigenously by Bhabha Atomic Research Centre (BARC), India. The study area has been divided into two zones on the basis of external gamma radiation dose rates as zone A (100-200 nSv/h) and zone B (above 200 nSv/h). Radon concentration in groundwater for various sites, both supported (contribution from dissolved 226Ra in water) and unsupported (contribution from aquifer rock), was estimated. Assuming that 238U and 226Ra are roughly in secular equilibrium in the aquifer rock, a model has been proposed to predict the uranium (238U) content in the aquifer rocks using onsite measured 222Rn concentration and dissolved 226Ra concentration in the groundwater. Results of a case study carried out at South Bengaluru city, Karnataka, India have been discussed in the paper.

Thoron Mitigation System based on charcoal bed for applications in thorium fuel cycle facilities (part 2): Development, characterization, and performance evaluation.

Exposure due to thoron (220Rn) gas and its decay products in a thorium fuel cycle facility handling thorium or 232U/233U mixture compounds is an important issue of radiological concern requiring control and mitigation. Adsorption in a flow-through charcoal bed offers an excellent method of alleviating the release of 220Rn into occupational and public domain. In this paper, we present the design, development, and characterization of a Thoron Mitigation System (TMS) for industrial application. Systematic experiments were conducted in the TMS for examining the 220Rn mitigation characteristics with respect to a host of parameters such as flow rate, pressure drop, charcoal grain size, charcoal mass and bed depth, water content, and heat of the carrier gas. An analysis of the experimental data shows that 220Rn attenuation in a flow through charcoal bed is not exponential with respect to the residence time, L/Ua (L: bed depth; Ua: superficial velocity), but follows a power law behaviour, which can be attributed to the occurrence of large voids due to wall channeling in a flow through bed. The study demonstrates the regeneration of charcoal adsorption capacity degraded due to moisture adsorption, by hot air blowing technique. It is found that the mitigation factor (MF), which is the ratio of the inlet 220Rn concentration (Cin) to the outlet 220Rn concentration (Cout), of more than 104 for the TMS is easily achievable during continuous operation (>1000 h) at a flow rate of 40 L min-1 with negligible (<1 cm of water column) pressure drop. The Thoron Mitigation System based on adsorption on charcoal bed offers a compact and effective device to remove 220Rn from affluent air streams in a space constrained domain. The prototype system has been installed in a thorium fuel cycle facility where it is being evaluated for its long-term performance and overall effectiveness in mitigating 220Rn levels in the workplace.

STUDY OF RADON FLUX FROM SOIL IN BUDHAKEDAR REGION USING SRM.

In the present study, the radon flux rate of the soil is measured using portable radon monitor (scintillation radon monitor) in the Budhakedar region of District Tehri, India. The study area falls along a fault zone named Main Central Thrust, which is relatively rich in radium-bearing minerals. Radon flux rate from the soil is one of the most important factors for the evaluation of environmental radon levels. The earlier studies in the Budhakedar region shows a high level of radon (>4000 Bq m-3). Hence, it is important to measure the radon flux rate. The aim of the present study is to calculate the average estimate of the surface radon flux rate as well as the effective mass exhalation rate. A positive correlation of 0.54 was found between radon flux rate and radon mass exhalation rate.

Oral hyposensitization in patients with contact dermatitis from Parthenium hysterophorus.

Parthenium hysterophorus is the commonest cause of airborne contact dermatitis in northern India. Treatment is mostly palliative and consists of repeated courses of antihistamines and topical and/or systemic corticosteroids. We have evaluated the effect of oral hyposensitization as an alternative therapeutic modality. In 70% of those patients who completed the study, there was a gradual improvement in their clinical status, as evident from a fall in their clinical severity score for eczema. 30% of patients had an exacerbation during the course of the study and hence hyposensitization in them was stopped. Patients tolerated therapy well and no significant side-effects were seen, except for abdominal pain, 'heartburn' and cheilitis.

Acute renal failure associated with freshwater fish toxin.

Clinical observations on toxicity after ingestion of gall bladder of Labeo rohita, a freshwater fish found commonly in India, were recorded from 22 patients between 1985 to 1990. The gall bladder in raw, cooked or desiccated form was swallowed as a traditional method of treatment for various chronic diseases. Patients generally presented with gastrointestinal symptoms such as cramping pain, nausea and vomiting within 12 hours (mean 4.6 +/- 3.7 hours) after ingestion. Subsequently renal failure was observed in all and hepatic dysfunction in some (36.3%) patients. The outcome in general is good. From the clinical course the role of toxic substance(s) is presumed as the causative factor(s), which needs further evaluation.

Polychemotherapy in squamous cell carcinoma of the buccal mucosa.

Thirty-nine patients with previously untreated squamous cell carcinoma of the buccal mucosa were treated by two polychemotherapeutic regimens. The first regimen consisted of bleomycin and methotrexate (BLM-MTX): bleomycin 30 mg was given intravenously twice weekly, and methotrexate 25 mg intravenously twice weekly for 2 1/2 and two weeks, respectively. The second program consisted of Cytoxan (cyclophosphamide), methotrexate and 5-FU (CMF): methotrexate 25 mg twice weekly for two weeks, Cytoxan 100 mg/day for two weeks, and 5-FU 500 mg twice weekly for 1 1/2 weeks. All of the patients were evaluated one week after completion of their chemotherapy regimen. Although the patients were not randomly allocated to either treatment, they matched in age and extent of disease. High response rates (88.9%) were noted with the BLM-MTX combination, which is comparable to the best responses reported previously using cis-platinum, Oncovin (vincristine), and methotrexate. This may suggest that buccal cancers are highly sensitive to an initial treatment by BLM-MTX, and therefore the authors highly recommend its use as preoperative adjuvant therapy in patients who present with Stage III and IV (Mo) disease.