Effluent

About: Effluent is a research topic. Over the lifetime, 32668 publications have been published within this topic receiving 533991 citations.

Wetlands for wastewater treatment and subsequent recycling of treated effluent: a review

Abstract: Due to water scarcity challenges around the world, it is essential to think about non-conventional water resources to address the increased demand in clean freshwater. Environmental and public health problems may result from insufficient provision of sanitation and wastewater disposal facilities. Because of this, wastewater treatment and recycling methods will be vital to provide sufficient freshwater in the coming decades, since water resources are limited and more than 70% of water are consumed for irrigation purposes. Therefore, the application of treated wastewater for agricultural irrigation has much potential, especially when incorporating the reuse of nutrients like nitrogen and phosphorous, which are essential for plant production. Among the current treatment technologies applied in urban wastewater reuse for irrigation, wetlands were concluded to be the one of the most suitable ones in terms of pollutant removal and have advantages due to both low maintenance costs and required energy. Wetland behavior and efficiency concerning wastewater treatment is mainly linked to macrophyte composition, substrate, hydrology, surface loading rate, influent feeding mode, microorganism availability, and temperature. Constructed wetlands are very effective in removing organics and suspended solids, whereas the removal of nitrogen is relatively low, but could be improved by using a combination of various types of constructed wetlands meeting the irrigation reuse standards. The removal of phosphorus is usually low, unless special media with high sorption capacity are used. Pathogen removal from wetland effluent to meet irrigation reuse standards is a challenge unless supplementary lagoons or hybrid wetland systems are used.

Effects of Urban Sewage on Dissolved Oxygen, Dissolved Inorganic and Organic Carbon, and Electrical Conductivity of Small Streams along a Gradient of Urbanization in the Piracicaba River Basin

Abstract: In Brazil most of the urban sewage is dumped without treatment into rivers. Because of this, it is extremely important to evaluate the consequences of organic matter rich sewage on the structure and functioning of river ecosystems. In this study we investigated the effects of urban sewage on the dissolved oxygen (O2), dissolved inorganic (DIC) and organic carbon (DOC), and electrical conductivity (EC) in 10 small streams of the Piracicaba River basin, southeast region of Brazil. In the Piracicaba River basin, which is one of the most developed regions of the country, only 16% of the total sewage load generated is treated. These streams were classified into two groups, one with heavy influence of urban sewage and another with less influence. Both concentrations and seasonal variability were distinct between the two groups. The streams that received sewage effluent had a combination of low O2 with high DIC, DOC, and EC. In the polluted streams, concentrations of dissolved carbon forms and EC were higher and O2 concentration lower during the low water period. In the less polluted streams seasonal variations in concentrations were small. We also investigated the efficiency of a sewage treatment plant installed two years ago in the catchment of one of these streams. It was observed an increase in the O2 concentration after the beginning of the treatment, and a decrease of DIC and DOC concentrations especially during the low water period. However, no significant change was observed in the EC, suggesting that the concentrations of major ions is still unaltered, and that a secondary treatment is necessary in order to reduce ion load into the stream.

Contamination of soil and plants with potentially toxic elements irrigated with mixed industrial effluent and its impact on the environment.

Abstract: For productive utilisation of effluent–contaminated agricultural land, mobilisation and statistical analysis of potentially toxic elements in soil and plants of fields irrigated with mixedindustrial effluent have been undertaken. Total Fe,Mn, Zn, Cu, Pb, Ni and Cr have been estimated in soiland plant species of contaminated and noncontaminatedsites. 18 plants species and 18 root adjacent soilsamples from contaminated Kalipur area and 11 plantsspecies and 11 root adjacent soil samples fromuncontaminated Madhabpur area comprising majorcrops, vegetables and weeds have been included in thestudy. It is revealed that Hibiscusesculentus, Lycopersicon esculentum and Luffa acutangula growing in effluent–contaminated field show mobilisation ratio 0.5 and simultaneously exhibithealthy gigantic morphology at the early floweringstage. Coriandrum sativum, Raphhanussativus, Solanum melongena, Spinaceaoleracea, Oryza sativum, Brassica oleraceashowed mobilization ratio >0.5 butmaintained normal growth. Based on mobilization ratioand external morphology, we suggest the cultivation ofplants H. esculentus, L. acutangula, L. esculentum in land irrigated with industrial effluent. The highest andsecond highest enrichment factor (EFpp)was found for Cd and Pb, respectively. Pearson'scorrelation coefficient indicated that the metal levelin soil is not the main factor governing metaluptake. This study will help in selecting plantspecies for cultivation in contaminated fields.