Media type is a critical design consideration when implementing biofiltration for drinking water treatment. Granular activated carbon (GAC) has been shown to provide superior performance when compared to a wide range of media types, largely due to its higher surface area. Engineered ceramic media is an attractive alternative to GAC as it has a similar surface area but at a lower cost. This pilot-scale biofiltration study compared the performance of GAC, anthracite and two different effective sizes of ceramic (CER) media (1.0 mm and 1.2 mm), in terms of dissolved organic carbon (DOC), head loss, turbidity, and disinfection by-product formation potential (DBPFP). Biological acclimation was monitored using adenosine tri-phosphate (ATP) measurements; biomass was further examined using laccase and esterase enzyme activity assays. When compared to other media types examined, biological GAC had higher (p > 0.05) removals of DOC (9.8 ± 3.8%), trihalomethane formation potential (THMFP, 26.3 ± 10.2%), and haloacetic acid formation potential (HAAFP, 27.2 ± 14.0%). CER media required 6-7 months to biologically acclimate, while filters containing GAC and anthracite were biologically active (>100 ng of ATP/g media) following 30-45 days of operation. Once acclimated, ATP values of 243 and 208 ng/g attained for CER 1.0 and 1.2, respectively, were statistically comparable to GAC (244 ng/g) and higher than anthracite (110 ng/g), however this did not translate into greater organics removal. Esterase and laccase enzyme kinetics were highest for GAC, while CER was shown to have greater biodegradation potential than anthracite. The four media types attained similar turbidity reduction (p > 0.05), however ceramic media filters were observed to have run times which were 1.5-2.3 times longer when compared to anthracite, which could represent potential cost savings in terms of energy for pumping and backwash requirements. Overall, ceramic media was shown to be a potential alternative to anthracite when considering biofiltration, especially during cold water conditions (T < 10 °C).
Background: Chronic viral hepatitis is a major global public health problem, an important cause of morbidity and mortality. We conducted this study to evaluate the behavioral risk factors of HBV infection and its association with HBsAg positivity among residents of Kaza sub-division of district Lahaul & Spiti in Himachal Pradesh. Material & Methods: The study was carried out by the Gastroenterology, Community Medicine, and Microbiology Department at Indira Gandhi Medical College Shimla at Kaza, a subdivision of Lahaul & Spiti. The cluster sampling technique was used to get the desired sample size of 4000. Forty clusters were chosen using a probability proportionate to size sampling method, and 100 research participants were added to each cluster using a simple random sampling method. The data was gathered using a pre-tested interview plan. A blood sample of 5ml from each study participant was obtained, and its HBsAg content was examined. Results: In our study, 2.7% of the interviewed respondents’ parents were positive for hepatitis B and 3.7% reported one positive family member. Injectable drug use was reported by 1.6 (68/4231). Among these users 8.8% (6/68) shared needles with other IDUs in last 12 months and 35.3% (24/68) used a common container to draw up drug solution. Sexual intercourse was reported to be experienced by 15.5 (655/4231) and 12.2% either did not disclose or were children. Out of those who ever experienced sexual/penetrative intercourse 38.3% (251/655) had reported it with someone else other than a spouse. Majority of these had two partners other than a spouse (30.3%; 76/251). Around 30% (195/655) reported of using a condom in their last intercourse. Body piercings or a tattoo from someone who doesn’t sterilize his or her equipment, including local treatment from lamas, was prevalent among 16.3% of the population (689/4231). Acupuncture was taken as a remedy for any medical condition by 9% of participants. Regression analysis also revealed that one infected family member emerged as an independent factor associated with HBsAg positive test after adjusting for confounders. Conclusion: Our study provided much important information concerning hepatitis B risk factors in this tribal group. Health education about behavioral risk factors among this tribal population should be the main intervention that might help limit the spread of these blood-borne infections.
In today's scenario, availability of natural aggregates is diminishing and simultaneously the waste generation due to debris of demolished buildings is increasing considerably. Incorporationg these demolished materials into construction process can provide a respite from both these issues. The aggregate from demolished structures mainly consists of 70-80% of concrete components as per different studies, so it will be very beneficial for the environment to recycle this aggregate for construction works. In this paper a review of contemporary practices of use of recycled concrete aggregate in pavement construction has been done.
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