Thermal modeling, characterization, and enviro-economic investigations on inclined felt sheet solar distiller for seawater desalination.

Sustainable desalination can be achieved by adopting renewable energy-based low-cost and low-impact desalting techniques. In this investigation, capability of inclined felt sheet solar distiller in desalting seawater is assessed by evaluating its performance, distillate water quality, economics, and environmental impacts. The distiller with 1.18-m2 aperture area produced around 4.60 L/day of distillate for a cumulative incident solar radiation intensity of about 20.52 MJ/m2 day. Its pollutant removal efficiency is very much superior to other available solar stills reported in literatures. Thermal model developed for estimating distiller's performance is able to predict its productivity with reasonable accuracy (only 8.0% deviation from experimental values) and was used for estimating distiller's performance in various seashore locations in India with varying clear days (191 to 246). Yearly mean distillate production and thermal and exergy efficiencies of the proposed distiller range between 3.60 to 4.50 L/day, 36.45 to 42.39%, and 2.85 to 3.65%, respectively, in east seashore locations of India. Moreover, 18.46 tons of CO2, 132.72 kg of SO2, and 54.20 kg of NO emission can be mitigated by adopting the distiller for potable water production. Distillate production cost of inclined felt sheet solar distiller is in the range of 1.15 to 2.29 INR/L and highly depends on the interest rate at which the distiller is financed. Generation of reasonable quantity of high-quality potable water at low cost with huge environmental benefits makes proposed inclined felt sheet solar distiller a suitable option for quenching thirst in coastal and remote locations.

Characterization of segregated greywater from Indian households-part B: emerging contaminants.

Emerging contaminants (ECs) have become an increasing area of concern due to the likely impacts of these compounds on human health and the environment. Generally, products which are used for households and personal care activities contribute to major percentage of ECs in household greywater. Not much information on the presence of xenobiotic organic compounds in greywater is currently available. Therefore, the present study focused on the qualitative and quantitative analyses of emerging contaminants from different classifications of Indian households. The qualitative screening of emerging pollutants by solid-phase extraction-gas chromatography and mass spectroscopy (SPE-GC-MS) showed the presence of 78 different emerging contaminants from three different sources, which are categorized into ten different groups based on their chemical properties. The quantitative analysis of few selected target pollutants such as phthalic esters, namely diethyl hexyl phthalate, diethyl phthalate, dibutyl phthalate, dioctyl phthalate, triclosan, bisphenol A, caffeine, acetaminophen, 3-methyl salicylic acid, 4-octylphenol, and 4-nonylphenol were found to be 0.38 ± 0.39 µg/L, 1.57 ± 1.54 µg/L, 4.77 ± 2.57 µg/L, 0.712 ± 0.17 µg/L, 5.82 ± 1.85 µg/L, 11.08 ± 2.64 µg/L, 2.30 ± 1.19 µg/L 13.18 ± 4.48 µg/L, 3.75 ± 1.90 µg/L, 4.95 ± 2.21 µg/L, and 5.96 µg/L, respectively. Risk assessment indicated that 63 compounds identified in the greywater can be considered priority pollutants. Based on the results obtained in the present study, effective zero-discharge liquid system can be designed for different sources of greywater and it can be recycled and reused without much risk. Graphical abstract .

Characterization of segregated greywater from Indian households: part A-physico-chemical and microbial parameters.

Greywater has attracted global attention as a feasible alternative water source over the last few decades. Reuse and recycling of greywater is an economically viable and attractive option for meeting the future water demand. However, its treatment and reliable reuse continue to be based on conventional parameters such as BOD, COD, turbidity, suspended solids and pathogen level. The current investigative study focused on the characterization of segregated grey wastewater (greywater from bathroom, laundry and kitchen) from different economic classes of Indian households which included physical and chemical parameters, organics, nutrients, pathogens, heavy metals, oil and grease and surfactants. Apart from this, the data related to water consumption, frequency and products used for their daily activities were gathered using a questionnaire survey. The average water consumption among different household was found to be 108 L per capita per day. The maximum concentrations of organics such as BOD (678.6 ± 179 mg/L), COD (1507 ± 508 mg/L) and TOC (176.4 ± 131 mg/L) were found in kitchen wastewater. However, maximum concentrations of surfactants (14.02 ± 3.74 mg/L) were obtained in laundry wastewater. Faecal coliform concentration was more in the households which had inhabitants of children below 4 years. Statistical analysis revealed that the parameters monitored differ significantly between different economic classes. The present study showed that the characteristics of greywater highly depend on the wastewater source, household behaviour and activities. This study will be helpful to design a sustainable cost-effective treatment system, enabling greywater generated from different sources to be safely recycled and reused by households. Graphical abstract.