Conversion of sewage sludge into biochar: A potential resource in water and wastewater treatment.

Production of biochar from sewage sludge (SS) is consistent with the goal of sustainable resource recovery and promotes a wastewater-based circular economy. Thermochemical conversion of SS to biochar resolves two major issues simultaneously as it minimizes the cost of disposal and acts as a resource to eliminate the toxic contaminants from water and wastewater. The reusability and ready availability of the biochar, irrespective of the season, makes it an economically viable material for wastewater treatment. In this review, explicit insights into the production, modification and usage of SS derived biochar are provided including (i) the production yield, (ii) characteristic features such as physical, chemical, electrochemical and morphological aspects, and (iii) impact on contaminant removal through adsorption, catalytic and electrochemical processes. Particular attention is given to the use of SS derived biochar as an adsorbent for contaminants present in wastewaters, the potential use of biochar as a catalyst and support material in advanced oxidation processes and the use of biochars as an electrode material. The effect of pyrolysis conditions and co-pyrolysis with other materials on biochar properties is explored and insight is provided into the toxicity of biochar components present at different process conditions.

Public Health Dentistry as a Career Choice - Attitude of Dental Undergraduate Students in Puducherry.

Background: To pursue further education in a particular specialty of dentistry, it is important for dental students to be aware of the "expectation" associated with any specific specialty in dentistry. Therefore students 'attitudes' towards 'expectations' of various specialties, to a large extent enables a meaningful understanding that facilitates appropriate planning in the dental sector for the community. Materials and Methods: A cross-sectional questionnaire based survey was conducted, which included, final year and dental interns studying in two dental institutions, in the State of Puducherry. It consisted of 27 questions that were graded using 5-point Likert scale. The responses for the attitude questions toward selecting Public Health Dentistry for post-graduation were categorized into three factors, negative attitude (includes score 0-21), neutral attitude (score 22-44), and positive attitude (score 45-64). Differences between groups were examined using t-test for proportions. The level of statistical significance was set at p < 0.05. Results: Among 221 respondents, 73 (33.0) were males and 148 (67.0) females. About (52.2%) of the respondents had positive attitude toward selecting Public Health Dentistry as their future career and (76.7%) had neutral attitude, around (5 %) had negative attitude towards the speciality for pursuing post-graduation in both the two institutions. Conclusion: Our study could highlight many factors namely gender, year of study etc which influence the attitude of students for selecting PHD as career choice. These specific factors could be kept in mind while course planning for government or private institutions so that maximum interest can be fetched among students.

Electrochemical-based approaches for the treatment of forever chemicals: Removal of perfluoroalkyl and polyfluoroalkyl substances (PFAS) from wastewater.

Electrochemical based approaches for the treatment of recalcitrant water borne pollutants are known to exhibit superior function in terms of efficiency and rate of treatment. Considering the stability of Perfluoroalkyl and polyfluoroalkyl substances (PFAS) are designated as forever chemicals, which generating from various industrial activities. PFAS are contaminating the environment in small concentrations, yet exhibit severe environmental and health impacts. Electro-oxidation (EO) is a recent development that treats PFAS, in which different reactive species generates at anode due to oxidative reaction and reductive reactions at the cathode. Compared to water and wastewater treatment methods those being implemented, electrochemical approaches demonstrate superior function against PFAS. EO completely mineralizes (almost 100 %) non-biodegradable organic matter and eliminate some of the inorganic species, which proven as a robust and versatile technology. Electrode materials, electrolyte concentration pH and the current density applying for electrochemical processes determine the treatment efficiency. EO along with electrocoagulation (EC) treats PFAS along with other pollutants from variety of industries showed highest degradation of 7.69 mmol/g of PFAS. Integrated approach with other processes was found to exhibit improved efficiency in treating PFAS using several electrodes boron-doped diamond (BDD), zinc, titanium and lead based with efficiency the range of 64 to 97 %.

Oral Hygiene Practices and Knowledge on Periodontal Diseases and Therapy: A Cross-Sectional Questionnaire Study on Gypsy Narikuravars in Puducherry.

Background: Gypsy "Narikuravars" constituted separate sociocultural groups having distinct cultures, customs, traditions, and lifestyles. Oral health-seeking behavior of this group remains to be an ignored part. This study aims to assess the oral hygiene practices and knowledge on periodontal diseases and therapy among Gypsy Narikuravars in Puducherry. Materials and Methods: The total study population consisted of 100 subjects, and a performed validated pro forma about oral hygiene practices and knowledge on periodontal diseases was used. Results: There is no significant association between sociodemographic factors and knowledge on periodontal disease and therapy. Majority (90%) of the participants have poor knowledge of periodontal disease and therapy. 56% of the participants used their fingers to clean the teeth, and very few subjects (13%) used toothbrush to clean their teeth, and most of the participants (92%) brushes once daily using manual method. Conclusion: The practice of poor oral hygiene and lack of knowledge on periodontal disease and therapy was observed. Hence, the implementation of oral health programs and provision of comprehensive health services for these Gypsy population should be a high priority.

Treatment of real wastewater by photoelectrochemical methods: An overview.

An inadequate and inefficient performance ability of conventional methods to remove persistent organic pollutants urges the need of alternative or complementary advanced wastewater treatments methods to ensure the safer reuse of reclaimed water. Photoelectrochemical methods are emerging as promising options among other advanced oxidation processes because of the higher treatment efficiency achieved due to the synergistic effects of combined photochemical and electrolysis reactions. Synergistic effects of integrated photochemical, electrochemical and photoelectrochemical processes not only increase the hydroxyl radical production; an enhancement on the mineralization ability through various side reactions is also achieved. In this review, fundamental reaction mechanisms of different photoelectrochemical methods including photoelectrocatalysis, photo/solar electro-Fenton, photo anodic oxidation, photoelectroperoxone and photocatalytic fuel cell are discussed. Various integrated photochemical, electrochemical and photoelectrochemical processes and their synergistic effects are elaborated. Different reactor configurations along with the positioning of electrodes, photocatalysts and light source of the individual/combined photoelectrochemical treatment systems are discussed. Modified photoanode and cathode materials used in the photoelectrochemical reactors and their performance ability is presented. Photoelectrochemical treatment of real wastewater such as landfill leachate, oil mill, pharmaceutical, textile, and tannery wastewater are reviewed. Hydrogen production efficiency in the photoelectrochemical process is further elaborated. Cost and energy involved in these processes are briefed, but the applicability of photocatalytic fuel cells to reduce the electrical dependence is also summarised. Finally, the use of photoelectrochemical approaches as an alternative for treating soil washing effluents is currently discussed.