Current Issue : July - September Volume : 2019 Issue Number : 3 Articles : 5 Articles
Recently, there has been series of petitions and protestations from petroleum\nproduction gas flare facility host communities in Nigeria about the degradation\nof their environment. This study was designed to conduct indoor dust\nrelated human health risk assessment for Cd, Pb, Mn and Ni. Deposited indoor\ndust samples were collected from sixteen (16) residential buildings distributed\nacross the four quarters of Ebedei waterside town in Nigeria, within\nthe vicinity of a petroleum production gas flare facility. The samples were digested\nand analysed for Cd, Pb, Mn and Ni concentrations using inductively\ncoupled plasma mass spectrometry (ICP-MS). Contamination/pollution index\n(C/PI) and human health risk assessments were conducted. The concentration\nranges of 1.2 - 14.9 mg/kg, 44.0 - 161.6 mg/kg and 221.3 - 752.0\nmg/kg, and below detection to 29.8 mg/kg were recorded for Cd, Pb, Mn and\nNi, respectively. C/PI analyses for metals in the indoor dusts investigated\nsuggested Cd levels to be polluted and Pb levels to be slightly polluted, while\nMn and Ni levels indicated contamination. Risk assessment studies indicated\nthat children may be more at risk for all the three exposure pathways. Exposure\nthrough the ingestion pathway indicated the highest risk for both the\nadult and children population....
Soil aquifer treatment (SAT) is a nature-inspired solution for improving the water quality\nthrough soil percolation. The biodegradation of organic matter typically occurs in the shallowest\nsoil layer and it depends on the contaminantâ??s characteristics (water solubility, molecular structure)\nand specific soil properties (pore size distribution). The present study aims at identifying which\ngrain size fraction of typically used sandy soils in the shallowest layer of SAT systems can provide\nthe optimal conditions for microbiological growth that can be reached by a trade-off between soil\nmoisture as well as nutrients and oxygen supply. For this, soil columns were used at a laboratory\nscale to determine the relationship between the pore size distribution of four different grain size\nfractions and biodegradation rates of organic matter from synthetic wastewater. The results obtained\nfrom this experimental setup indicate that bacterial colonies reached optimum growth when about\n60% of the available pore space was filled with water. For the selected soil, this was achieved by the\nfraction with grain sizes in the range of 630 micron to 1000 micron, having pore diameters between 87 micron\nand 320 micron and a mean pore diameter of 230 micron....
This research presents an attempt of using wastewater from stone slurry\nwaste in production of concrete. Several concrete mixtures were prepared by\nusing tap water and stone slurry wastewater at different w/c ratios and replacement\nratios of wastewater in substitute of tap water. Testing of concrete\nsamples included slump, compressive strength, flexural strength and absorption.\nTest results showed reduction of workability (slump) at all w/c ratios\nand replacement ratios. The maximum compressive strength didnâ??t change\nsignificantly at w/c = 0.7 and 28 days of curing compared with compressive\nstrength at w/c = 0.5 and 0.6. From linear regression of the experimental results,\nthe results showed that at 20% replacement ratio of tap water with\nwastewater, the reduction in compressive strength was insignificant (not\ngreater than 10% to 15%). Test results showed varying reduction of absorption\nat different w/c and replacement ratios, up to 62% at w/c = 0.5....
The most visible uncontrolled landfill sites were selected in the western and\neastern parts of the territory of Georgia. Particularly, in eastern Georgia the\nregions of Mtskheta-Mtianeti and Kvemo Kartli have been researched; and in\nwestern Georgia Imereti and Samtskhe-Javakheti correspondingly. Both\nchemical and microbiological analyses were conducted in the samples taken\nfrom their adjacent territories. In case the landfill site is located near the river,\nduring field works using portable equipment main physical-chemical indicators\nof surface waters were determined. After processing of the obtained results the\ncorresponding estimations were provided. The risks due to the environmental\npollution and negative impacts on population health were assessed....
Previous studies on the water quality of surface runoff often focused on the chemical\noxygen demand (COD), nitrogen, phosphorus, and total suspended solid (TSS), but little is known in\nterms of the inorganic suspended solids (ISS). This research investigated the effects of ISS carried\nby surface runoff on the treatment efficiency of the pretreatment facilities and the ratio of mixed\nliquor volatile suspended solid to mixed liquor suspended solid (MLVSS/MLSS) of the activated\nsludge in a wastewater treatment plant (WWTP) with the anaerobic-anoxic-oxic (AAO) process in\nChongqing city, China. The results showed that the surface runoff had a long-lasting impact on the\ngrit removal capacity of the grit chamber, affecting the normal operation after the rainfall. In contrast,\nthe primary sedimentation tank showed strong impact resistance with higher removal rates of COD,\nTSS, and ISS. Nonetheless, the primary settling tank aggravates the removal of organic carbon in\nsewage during rainfall, having a negative impact on subsequent biological treatment. The ISS in the\nsurface runoff could increase the sludge concentration and decrease the MLVSS/MLSS ratio. After\nrepeated surface runoff impact, the MLVSS/MLSS ratio in the activated sludge would drop below\neven 0.3, interrupting the normal operation of WWTP....
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