Traffic air pollution monitoring based on an air-water pollutants deposition device

An air water surface sampler device was developed and used to evaluate the atmosphere deposition due to the urban traffic air pollution in the business center of a mid-sized city. The indicator adopted to assess the cumulative air pollutant deposition in the surface of the device was the electric conductivity that was measured on a regular basis during the experiment. Additionally a digital camera was used to count the passing traffic in the road of the study site. Water samples were also taken from the device reservoir and dissolved metals concentrations (Cooper, Iron and Zinc) and acidity/alcalinity were determined in the laboratory. The obtained results were compiled and analyzed in order to evaluate the performance of the device and the relation between the atmospheric deposition and the traffic activity under different meteorological conditions. The research successfully proved that the device was able to evaluate the impact of pollutant emissions related to city traffic. It was also proved that electric conductivity can be used as an indicator to evaluate the cumulative deposition of air pollutants from road traffic. A significant correlation (Spearman rank) between the accumulated traffic and electric conductivity (dry period: ϱ= 0.991626 and wet period: ϱ= 0.810526) was observed.The authors gratefully acknowledge to Erasmus Mundus ECW EUROASIA-lot 12 (REF. 2009-1797) for the financial support granted through a scholarship for the Urban Engineering Master Course, to the Territory Environment and Construction Research Centre of University of Minho for the use of laboratory facilities, and to the school staff of the study site for their cooperation during the installation of equipment for this research. The authors gratefully acknowledge to anonymous reviewers for their important contributions to the final version of the paper

Sanitation and dewatering of human urine via membrane bioreactor and membrane distillation and its reuse for fertigation

Source separation and recovery of human urine have often been proposed as an effective way to achieve a more sustainable waste-to-resource cycle. Its high density of available macronutrients (N-P-K) in urine makes it an ideal raw material for the production of fertiliser. However, to improve the safety and public acceptance of urine-based fertilisers, odour and pathogens must be removed. In this work, low-temperature DCMD was investigated a mean to produce a non-odorous high-concentration liquid fertiliser. The effectiveness of urine-fertiliser in hydroponically growing leafy vegetables was benchmarked with a commercial solution. Also, prior to the DCMD, urine was biologically oxidised through an MBR which removed over 95% of the DOC and converted almost 50% of the NH3 into NO3-. The results showed that, despite the high salinity and high LMW organics in human urine, MD was still able to achieve a final product with TDS concentration up to 280 g.L-1. A sharp flux decline was measured after 80% water recovery, but alkaline cleaning effectively removed the thick fouling layer and fully recovered the initial flux. When used to grow lettuce and Pak Choi hydroponically, the produced urine fertiliser achieved promising performances as the biomass from the aerial part of the plants was often similar to the one obtained with commercial fertilisers. Overall, this article investigates the whole urine-to-biomass cycle, from collection to treatment to plant growth tests. (C) 2020 Elsevier Ltd. All rights reserved