Development of an integrating coagulation and reverse osmosis system to treat highly turbid water using synthesized coagulants.

In the present study a coagulation process was used as a pretreatment for a reverse osmosis (RO) membrane with turbid raw water collected from Bisalpur dam, Rajasthan, India. To optimize the coagulation performance, three kinds of coagulant, namely, alum (commercially available), synthesized inorganic polymeric coagulant-medium basicity (IPC-M), and inorganic polymeric coagulant-ultrahigh basicity (IPC-UH) were examined for turbidity removal with varying operating parameters. It was observed that in the optimum pH range of 6-7, the IPC-UH was the best performing coagulant with a 0.99 mg/L equivalent Al2O3 dose, revealing 2 NTU residual turbidity and residual aluminium of 0.001 mg/L. Moreover, the Langelier saturation index and Ryznar stability index values were evaluated at optimum conditions for all the three coagulants providing negligible scaling potential. Furthermore, the coagulant-treated water (100 L) was fed to the RO membrane, and the performance was noted in terms of flux, pressure, and total dissolved solids. It was observed that IPC-UH had the lowest reduction in permeate flux of 0.78 L/min/m2 compared with the commercially available coagulant alum (0.90 L/min/m2). Also, an increased feed pressure was observed for all the coagulant-treated waters with the lowest value of 2.3 kg/cm2 for IPC-UH, which was 2.5 kg/cm2 for alum (commercially available coagulant). Therefore, integration of coagulation before the RO system resulted in effective pretreatment of turbid water with very minute scaling.

Successful application of wastewater-based epidemiology in prediction and monitoring of the second wave of COVID-19 with fragmented sewerage systems-a case study of Jaipur (India).

The present study tracked the city-wide dynamics of severe acute respiratory syndrome-corona virus 2 ribonucleic acids (SARS-CoV-2 RNA) in the wastewater from nine different wastewater treatment plants (WWTPs) in Jaipur during the second wave of COVID-19 out-break in India. A total of 164 samples were collected weekly between February 19th and June 8th, 2021. SARS-CoV-2 was detected in 47.2% (52/110) influent samples and 37% (20/54) effluent samples. The increasing percentage of positive influent samples correlated with the city's increasing active clinical cases during the second wave of COVID-19 in Jaipur. Furthermore, wastewater-based epidemiology (WBE) evidence clearly showed early detection of about 20 days (9/9 samples reported positive on April 20th, 2021) before the maximum cases and maximum deaths reported in the city on May 8th, 2021. The present study further observed the presence of SARS-CoV-2 RNA in treated effluents at the time window of maximum active cases in the city even after tertiary disinfection treatments of ultraviolet (UV) and chlorine (Cl2) disinfection. The average genome concentration in the effluents and removal efficacy of six commonly used treatments, activated sludge process + chlorine disinfection (ASP + Cl2), moving bed biofilm reactor (MBBR) with ultraviolet radiations disinfection (MBBR + UV), MBBR + chlorine (Cl2), sequencing batch reactor (SBR), and SBR + Cl2, were compared with removal efficacy of SBR + Cl2 (81.2%) > MBBR + UV (68.8%) > SBR (57.1%) > ASP (50%) > MBBR + Cl2 (36.4%). The study observed the trends and prevalence of four genes (E, RdRp, N, and ORF1ab gene) based on two different kits and found that prevalence of N > ORF1ab > RdRp > E gene suggested that the effective genome concentration should be calculated based on the presence/absence of multiple genes. Hence, it is imperative to say that using a combination of different detection genes (E, N, RdRp, & ORF1ab genes) increases the sensitivity in WBE.

Sewage surveillance for the presence of SARS-CoV-2 genome as a useful wastewater based epidemiology (WBE) tracking tool in India.

The infection with SARS-CoV-2 is reported to be accompanied by the shedding of the virus in fecal samples of infected patients. Earlier reports have suggested that COVID-19 agents can be present in the sewage samples and thus it can be a good indication of the pandemic extent in a community. However, no such studies have been reported in the Indian context. Hence, it becomes absolutely necessary to detect the presence of the SARS-CoV-2 in the wastewater samples from wastewater treatment plants (WWTPs) serving different localities of Jaipur city. Samples from different WWTPs and hospital wastewater samples were collected and wastewater based epidemiology (WBE) studies were carried out using the RT-PCR to confirm the presence of different COVID-19 target genes namely S gene, E gene, ORF1ab gene, RdRp gene and N gene. The results revealed that the untreated wastewater samples showed the presence of SARS-CoV-2 viral genome, which was correlated with the increased number of COVID-19 positive patients from the concerned areas, as reported in the publically available health data. This is the first study that investigated the presence of SARS-CoV-2 viral genome in wastewater, at higher ambient temperature (45 °C), further validating WBE as potential tool in predicting and mitigating outbreaks.

Organic matter determination for street dust in Delhi.

The organic matter of street dust is considered as one of the causes for high human mortality rate. To understand the association, the street dust samples were collected from four different localities (industrial, residential, residential-commercial, and commercial) situated in the greater Delhi area of India. The loss-on-ignition method was used to determine the organic matter (OM) content in street dust. The OM content, potassium, calcium, sulfate, and nitrate concentrations of street dust in Delhi, India is measured to understand the spatial variation. Correlation analysis, analysis of variance, and factor analysis were performed to define the sources. The dust OM level ranges from 2.63 to 10.22 %. It is found through correlation and factor analysis that OM is primarily contributed from secondary aerosol and vehicular exhaust. The OM levels suggest that the use of a residential-commercial site for commercial purposes is polluting the street dust and creating the environmental and human health problems.

Fluoride occurrences, health problems, detection, and remediation methods for drinking water: A comprehensive review.

Fluoride contamination has become a considerable threat to our society worldwide. Fluoride in drinking water is primarily due to rich fluoride soil, volcanic activity, forage, grasses and grains, and anthropogenic reasons. World Health Organization has regulated the upper limit for fluoride in drinking water to be 1.5 mg/L while different countries have set their standards according to their circumstances. Excess amounts of fluoride ions in drinking water can cause dental fluorosis, skeletal fluorosis, arthritis, bone damage, osteoporosis, muscular damage, fatigue, joint-related problems, and chronicle issues. In extreme conditions, it could adversely damage the heart, arteries, kidney, liver, endocrine glands, neuron system, and several other delicate parts of a living organism, briefed in the present article. Moreover, a comprehensive scenario for the situations in countries like, China, Canada, Mexico, United States, Yemen, Pakistan, Saudi Arabia, South Korea, Sri Lanka, Indonesia, Iran, Turkey, Australia, and India affected with high fluoride levels in ground water has been described. To analyze the presence of fluoride molecule, out of different detections methods, ion selective and colorimetric method has been adopted for real situation in the field of water application. Also, different methods to remove fluoride from water like reverse osmosis, nano filtration, adsorption, ion-exchange, and precipitation/coagulation with their removal mechanism were highlighted in the review. Moreover, the applicability of the approach with the prospect of country's economic status has been discussed, due to high cost and maintenance the membrane technology is not popular in developing countries like India, Senegal, Tanzania, and Kenya which employ adsorption and coagulation-precipitation for fluoride removal. It is noticeable from literature study that different approaches show unique potential for defluoridation. Some key parameters and mechanistic adaptations which could pave the defluoridation methods to newer horizons have been put forward.

Removal of fluoride from water by using a coagulant (inorganic polymeric coagulant).

Excess fluoride (F) ion of drinking water is a major problem in many areas of India and causes harmful effects such as dental and skeletal fluorosis. The World Health Organization (WHO 2004) recommends an upper limit of 1.5 mg/L fluoride in drinking water, and the concentration of fluoride in groundwater has been found 10-20 times higher in many of the States in India. In this study, the performance of inorganic polymeric coagulant (IPC) named as IPC-23, IPC-13, IPC-17, and alum for fluoride removal from drinking water was investigated. The amount of IPC was decided according to the Al2O3 amount present in the alum dose recommended in the batch Nalgonda defluoridation technique. The effects of coagulant dosage (IPC) at different pH and initial concentrations of fluoride on fluoride removal have been studied. The synthetic sample having a fluoride concentration of 2 to 6 mg/L was treated at the optimized dosage and residual fluoride was reduced to 1.0 to 1.2 ppm with IPC-17. Residual aluminum in treated water was well within WHO norms (< 200 µg/L) for drinking water. Optimum pH for fluoride removal was 6.5, and there was deterioration in the performance of IPC at both lower and higher pH.

Recurrent acute respiratory tract infections in areas with high nitrate concentrations in drinking water.

A review of the literature indicated an association among high nitrate ingestion, methemoglobinemia, and pathologic changes in bronchi and lung parenchyma. The present study examined a possible correlation among drinking water nitrate concentration, methemoglobin levels, cytochrome b(5) reductase activity, and acute respiratory tract infection with a history of recurrence (RRTI). Our study was conducted in five village units in the state of Rajasthan, India, with nitrate concentrations of 26, 45, 95, 222, and 459 mg NO(3) ion/L. We randomly selected 88 children. The children were up to 8 years of age, age matched, and represented 10% of the total population of these areas. We obtained detailed RRTI histories and conducted medical examinations. Methemoglobin levels and cytochrome b(5) reductase activity were estimated biochemically. The data collected were statistically analyzed using spreadsheet software on a personal computer. We observed strong interdependence between methemoglobin levels and RRTI in children up to 8 years of age. Methemoglobin levels alone explained 80% of the variation in the RRTI cases. This study indicates that methemoglobinemia, secondary to high nitrate ingestion in drinking water, causes RRTI. Increased production of methemoglobin and free radicals of nitric oxide and oxygen due to nitrate metabolism in the body lead to alveolar damage and mismatching of ventilation and perfusion, which may be the reason for high mortality in children due to RRTI.

Simultaneous carbon and nitrogen removal from high strength domestic wastewater in an aerobic RBC biofilm.

High strength domestic wastewater discharges after no/partial treatment through sewage treatment plants or septic tank seepage field systems have resulted in a large build-up of groundwater nitrates in Rajasthan, India. The groundwater table is very deep and nitrate concentrations of 500-750 mg/l (113-169 as NO3(-)-N) are commonly found. A novel biofilm in a 3-stage lab-scale rotating biological contactor (RBC) was developed by the incorporation of a sulphur oxidising bacterium Thiosphaera pantotropha which exhibited high simultaneous removal of carbon and nitrogen in fully aerobic conditions. T. pantotropha has been shown to be capable of simultaneous heterotrophic nitrification and aerobic denitrification thereby helping the steps of carbon oxidation, nitrification and denitrification to be carried out concurrently. The first stage having T. pantotropha dominated biofilm showed high carbon and NH4(+)-N removal rates of 8.7-25.9 g COD/m2 d and 0.81-1.85 g N/m2 d for the corresponding loadings of 10.0-32.0 g COD/m2 d and 1.0-3.35 g N/m2 d. The ratio of carbon removed to nitrogen removed was close to 12.0. The nitrification rate increased from 0.81 to 1.8 g N/m2 d with the increasing nitrogen loading rates despite a high simultaneous organic loading rate. However, it fell to 1.53 g N/m2 d at a high load of 3.35 g N/m2 d and 32 g COD/m2 d showing a possible inhibition of the process. A simultaneous 44-63% removal of nitrogen was also achieved without any significant NO2(-)-N or NO3(-)-N build-up. The second and third stages, almost devoid of any organic carbon, acted only as autotrophic nitrification units, converting the NH4(+)-N from stage 1 to nitrite and nitrate. Such a system would not need a separate carbon oxidation step to increase nitrification rates and no external carbon source for denitrification. The alkalinity compensation during denitrification for that destroyed in nitrification may also result in a high economy.

A statistical study on in vivo sorption and desorption of water in ichthyosis vulgaris.

Experiments on the variation of electrical conductance on sorption and desorption of water were performed on the skin of 34 subjects: 17 ichthyosis vulgaris patients and 17 normal subjects, matched for age and gender, under different ambient conditions. An exponential model of the form ft = theta oe theta t, where ft denotes fractional conductance at time t, describes the process of desorption with high accuracy. The parameter theta, identifiable as the rate of desorption, is significantly different between the ichthyotic and normal populations. The study discusses the impaired barrier function of the ichthyotic skin.

Methaemoglobinaemia in areas with high nitrate concentration in drinking water.

BACKGROUND: An epidemiological investigation was undertaken in all age groups to assess the prevalence of methaemoglobinaemia in areas with high nitrate concentration in drinking water. METHODS: Five areas were selected with an average nitrate concentration (as nitrate) of 26, 45, 95, 222 and 459 mg nitrate ions/litre in drinking water. These areas were visited and the house schedule (containing name, age, sex and weight of the family members) prepared in accordance with the statistically designed protocol. In all, 178 persons, matched for age and weight, were selected and arranged in five age groups. They constituted 10% of the total population of each of these areas. A detailed history of the selected population was taken, medical examination conducted and blood samples taken to ascertain the level of methaemoglobin. The collected data were subjected to statistical analysis to ascertain a relationship between nitrate concentration and methaemoglobinaemia. RESULTS: High nitrate concentrations cause severe methaemoglobinaemia (7%-27% of Hb) in all age groups, especially in the age group of less than 1 year and above 18 years. The lower levels of methaemoglobin in the age group of 1-18 years is probably due to better reserve of cytochrome b5 reductase activity and its adaptation to increasing nitrate concentration in water to compensate for methaemoglobinaemia in this age group. CONCLUSION: We conclude that high nitrate ingestion causes methaemoglobinaemia in all age groups. Cytochrome b5 reductase activity and its adaptation with increasing water nitrate ingestion plays a role in compensating for the methaemoglobinaemia.

Recurrent diarrhea in children living in areas with high levels of nitrate in drinking water.

Given that there was documented evidence of an association between diarrhea and high nitrate ingestion, the authors examined drinking water nitrate concentration and its possible correlation(s) with methemoglobin levels, cytochrome b5 reductase activity, and recurrent diarrhea. In addition, the authors studied histopathological changes in the intestines of rabbits in an animal model. Five village areas were studied, and nitrate concentrations (expressed in mg of nitrate per liter of water) of 26, 45, 95, 220, and 459 existed in the respective villages. The study included 88 randomly selected children who were 8 yr of age or younger; they represented 10% of the total population of each of the areas. Detailed histories of recurrent diarrhea were noted, and medical examinations were conducted. Cytochrome b5 reductase activity and methemoglobin levels were estimated biochemically. Collected data were analyzed statistically with Microsoft Excel software. In addition, the authors exposed rabbits to various levels of nitrate, and histopathological changes of the stomach and intestine (small and large) were evaluated. There was a strong relationship between nitrate concentration and recurrent diarrhea; 80% of the recurrent diarrhea cases were explained by nitrate concentration alone. In the rabbit intestines, lymphocytic infiltration and hyperplasia characterized the submucosa as nitrate concentrations increased.

Compensatory hyperparathyroidism following high fluoride ingestion - a clinico - biochemical correlation.

OBJECTIVE: To evaluate the effect of varying ingestion of drinking water containing high fluorides and its effect on serum parathyroid hormone. DESIGN: Cross sectional clinical study. SETTING: S.M.S. Medical College, Jaipur. SUBJECT: 200 children were selected from four areas (50 from each area) consuming water containing 2.4, 4.6, 5.6 and 13.5 mg/l of fluoride. All children were in an age group of 6 to 12 years. METHODS: All children were graded for clinical, radiological and dental fluorosis and biochemical estimations were made for serum calcium, serum and urinary fluoride and serum parathyroid hormone. RESULTS: Serum calcium levels were well within normal range in the patients of all areas but an increase in serum parathyroid levels (S. PTH) was noted. The increased S. PTH was well correlated with increase in fluoride ingestion. The severity of clinical and skeletal fluorosis was observed to increase with increase in S. PTH concentration. CONCLUSIONS: High Fluoride ingestion has a definite relationship with increased parathyroid hormone secretion, which may be responsible for maintaining serum calcium levels and may have a role in toxic manifestations of fluorosis.

Residual aluminium in water defluoridated using activated alumina adsorption--modeling and simulation studies.

The removal of fluoride from drinking water by the method of adsorption on activated alumina is found superior than other defluoridation techniques mostly due to the strong affinity between aluminium and fluoride. Dissolution of aluminium from the alumina surfaces into its free and hydroxide ions in the aqueous medium is reported to be very low, but the presence of high fluoride concentrations may increase its solubility due to the formation of monomeric aluminium fluoride and aluminium hydroxyl fluoride complexes. An Activated Alumina Defluoridation Model Simulator (AAD) has been developed to represent fluoride adsorption on the basis of the surface complexation theory incorporating aspects of aluminium solubility in presence of high fluoride concentrations and pH variations. Model validations were carried out for residual aluminium concentrations in alumina treated water, by conducting a series of batch fluoride adsorption experiments using activated alumina (grade FB101) treating fluoride concentrations of 1-10mg/L, at varying pH conditions. The total residual aluminium in the defluoridated water is due to presence of both dissolved and precipitated Al-F complexed forms. The Freundlich adsorption isotherm was found fit for fluoride adsorption capacity versus residual fluoride concentrations for pH=7.5, and the relationship is given by the linearised equation log(x/m)=logk+(1/n) logC(e) with values of k=0.15mg/g and 1/n=0.45 indicating favorable adsorption. The relationship is linear in the region of low fluoride concentrations, but as concentrations of fluoride increased, the formation of the dissolved AlF(3)(0) complexes was favored than adsorption on alumina, and hence makes the isotherm nonlinear. The AAD simulations can predict for operating fluoride uptake capacity in order to keep the residual aluminium within permissible limits in the alumina treated water.

Is there a need of extra fluoride in children?

The issues related to fluoridation of water or fortification of tooth paste with compounds of fluorides are controversial. Fluoride is stored mainly in the bones, where it increases the density and changes the internal architecture, makes it osteoporotic and more prone to fractures. Fluoride consumption by human beings increases the general cancer death rate, disrupts the synthesis of collagen and leads to the breakdown of collagen in bone, tendon, muscle, skin, cartilage, lungs, kidney and trachea, causing disruptive effect on various tissues in the body. It inhibits antibody formation, disturbs immune system and makes the child prone to malignancy. Fluoride has been categorized as a protoplasmic poison and any additional ingestion of fluoride by children is undesirable.

Surface pH of Normal Skin.

The skin furface pH of 55 brown-skinned individuals (Indians) comprising of 30 males and 25 females in the age range 12-58 years has been measured at the forehead (FH) and the back of the wrist (BW). The mean values of skin pH at FH and BW are 5.51 + 0.32 and 5.56 + 0.40 respectively for male. The corresponding female values are 5.73 + 0.032 and 5.84 + 0.28 statistical analysis of the data shows that (i) the dependence of skin surface pH on age is not significant, (ii) the male skin is slightly, but significantly more acidic than the female one, (iii) the mean values of skin pH at forehead and at back of the wrist do not differ significantly for male ; the difference however is significant for female at 5% level, (iv) there exists a significant positive correlation ( r=0.77 for male and r + 0.71 for female) between the pH's of the forehead (x2) and the back of the wrist (z3). The regression equation of x2 on x3 are: x2= 2.13+0.61 for male and x2=1.05 + 0.80x3 for female.

Need for revision of nitrates standards for drinking water: a case study of Rajasthan.

An attempt has been made to classify ground waters in various districts of Rajasthan based on distribution of nitrate in their drinking water samples. It is seen that nitrate in ground water is unevenly distributed in the state. Major parts of Churu, Alwar, Bharatpur, Jalore, Jaipur, Sikar, Tonk and Jhunjhunu, are inherited by nitrate rich ground waters while districts like Banswara, Bundi, Bikaner, Chittor, Kota and Jhalawar have low nitrates in their ground waters at many places. It is well documented internationally that water supplied containing high levels of nitrate have been responsible for cases of infantile methemoglobinemia which may ultimately lead to death. A very high infant mortality rate in Rajasthan might be a consequence of high nitrates in drinking water supply. Some recent studies have shown that nitrates in drinking water besides causing methemoglobinemia can result in various other clinical manifestations like recurrent stomatitis, recurrent respiratory tract infections (RRTI) etc. These findings have indicated that a rethinking has to be given to the existing standards for nitrates in drinking water. Based on potential nitrate toxicity studies in view of above health effects the whole region has been classified into five water quality zones, namely, safe, mild, moderately problematic, highly problematic and dangerous. For areas falling under fourth and fifth zones it is recommended that immediate measures be taken to overcome the adverse health effects.

Iontophoretic Treatment of Hyperkeratosis with Sodium Salicylate.

Ten patients having hyperkeratosis with moderate to severe fissures on palms and soles were treated with iontophoresis using 5-10% aqueous solution of sodium salicylate. The results were excellent within a period of 3-4 weeks (6-8 sittings each for a period of 10-15 minutes). The treatment was free from the problems of salicylism. Follow-up in some of the reclcitrant cases for 4 months after stop the treatment and with no local application, showed neither any relapse nor deterioration. Sodium salicylate iontophoresis in hyperkeratosis seems to be safe well tolerated and far more effective than the usual local applications of salicylic acid.