Diurnal patterns of micropollutants concentrations in domestic greywater

<p>In recent years, much interest has been given to presence of micropollutants in municipal wastewater, some of which are suspected to be endocrine disruptors, toxic or carcinogenic. Much less attention has been paid to their presence in greywater. The present research studies the diurnal patterns of micropollutants in greywater and computes their daily loads. Monitoring was carried-out using auto-controlled sampling system, designed to overcome the erratic greywater generation. Two main generation periods were identified: morning (5:00–11:00) and evening-night (18:00–2:00), contributing about 20% and >50% of daily greywater discharge, respectively. Average specific daily greywater discharge was 57 L p⁻¹d⁻¹, which matches reported value for greywater generated by showers and washbasins in Israel. The most frequently detected micropollutants in this study were methylparben (preservative), galaxolide (fragrance) and oxybenzone (UV-filter), which are common ingredients in many personal care-products. Their daily loads were 2, 840, 1, 887 and 728 µg p⁻¹d⁻¹, respectively.</p

Liquid-Desiccant Vapor Separation Reduces the Energy Requirements of Atmospheric Moisture Harvesting

An innovative atmospheric moisture harvesting system is proposed, where water vapor is separated from the air prior to cooling and condensation. The system was studied using a model that simulates its three interconnected cycles (air, desiccant, and water) over a range of ambient conditions, and optimal configurations are reported for different operation conditions. Model results were compared to specifications of commercial atmospheric moisture harvesting systems and found to represent saving of 5–65% of the electrical energy requirements due to the vapor separation process. We show that the liquid desiccant separation stage that is integrated into atmospheric moisture harvesting systems can work under a wide range of environmental conditions using low grade or solar heating as a supplementary energy source, and that the performance of the combined system is superior

Simulation method for stochastic generation of domestic wastewater discharges and the effect of greywater reuse on gross solid transport

<p>Together with significant water saving, due to lower wastewater discharges, greywater reuse (GWR) may also increase the impacts of faecal matter and other gross solids (GS) on sewer systems (sedimentation, blocking). Modelling and assessments of these effects require detailed descriptions of individual domestic wastewater streams. A novel stochastic methodology to generate such streams was developed and validated. The generator was developed while considering dependencies between in-house water-use events, and their varying degree of elasticity. These generated streams served as input to a sewer model, where scenarios of GWR were simulated and their effects on GS transport were examined. Extensive GWR decreases GS movement mostly in upstream links. Nevertheless, transient high flows, characterising these links, may move stationary GS and prevent blockages. The developed generator can be adopted to other sewer-related studies. Intelligent implementation of the results can assist in introducing GWR, or other water saving measures to the urban sector.</p