Mitigation of Emerging Pollutants and Pathogens in Decentralized Wastewater Treatment Processes: A Review

Author(s):  
Selina Hube ◽  
Bing Wu
2005 ◽  
Vol 40 (4) ◽  
pp. 500-509 ◽  
Author(s):  
Nurudeen A. Oladoja ◽  
Imohimi O. Asia

Abstract This study aimed to design an uncomplicated, reliable, technologically simple and low energy consuming decentralized wastewater treatment system using kaolinitic soil-clay fortified with stone pebbles to enhance the permeability to water. Soilclay samples were obtained from different deposits in Nigeria viz: Auchi (AU), Ozanagogo (OZ) and Ubulu-Uku (UB). The geochemical analysis of the soil-clay samples was done using an atomic absorption spectrophotometer (AAS). The mineralogical analysis, studied with an X-ray diffractometer, revealed the presence of kaolinite as the domineering clay mineral present. Illite was also found in the clay OZ and AU (6.50% and 0.50%, respectively). Composite wastewater samples were obtained from brewery, textile and polymer industries. Performance efficiency studies were conducted to determine the best combination ratio of pebbles/soil-clay. Soil-clay fortified with pebbles in combination ratios of 1:3 (i.e., pebbles: soil-clay = 1:3 [w/w]) showed optimum water treatment while the combination 3:1 gave the least. The flow rate studies showed that the wastewater had a longer residence time in non-fortified soil-clay than in fortified soil-clay. Two modes of treatment methods were employed: single and double column treatment (SCT and DCT). The two methods gave effluents with goodquality characteristics but those from the DCT were of better quality. The quality of effluents also varied from one fortified column to another. The fortified column containing OZ exhibited the best performance while UB showed the least performance in the entire treatment processes. Results obtained from the studies on the effects of repeated use on the performance efficiency of the fortified soil-clay showed that the pH of effluents decreased with time toward acidity; the amount of TS also decreased with time; and, as the COD value increased, depletion in the DO was also recorded.


2020 ◽  
Vol 10 (5) ◽  
pp. 1886 ◽  
Author(s):  
Diana Pacheco ◽  
Ana Cristina Rocha ◽  
Leonel Pereira ◽  
Tiago Verdelhos

The need to reduce costs associated with the production of microalgae biomass has encouraged the coupling of process with wastewater treatment. Emerging pollutants in municipal, industrial, and agricultural wastewaters, ranging from pharmaceuticals to metals, endanger public health and natural resources. The use of microalgae has, in fact, been shown to be an efficient method in water-treatment processes and presents several advantages, such as carbon sequestration, and an opportunity to develop innovative bioproducts with applications to several industries. Using a bibliometric analysis software, SciMAT, a mapping of the research field was performed, analyzing the articles produced between 1981 and 2018, aiming to identifying the hot topics and trends studied until now. The application of microalgae on water bioremediation is an evolving research field that currently focuses on developing efficient and cost-effective treatments methods that also enable the production of add-value products, leading to a blue and circular economy.


2006 ◽  
Vol 5 (4) ◽  
pp. 685-692
Author(s):  
Elisabeta Chirila ◽  
Ionela Carazeanu Popovici ◽  
Techin Ibadula ◽  
Alice Iordache

Author(s):  
N. Zaletova ◽  
S. Zaletov

Биологический метод очистки сточных вод представляет собой сложный многокомпонентный процесс, ключевой составляющей которого является работа ферментной системы. Известно, что одним из важнейших ферментов, обеспечивающих биологический процесс, являются дегидрогеназы. Полностью сложнейший механизм действия ферментов до конца пока не раскрыт, однако в практике контроля процессов биологической очистки используется показатель дегидрогеназной активности ила. Результаты исследований позволили дополнить имеющуюся информацию фактическими данными о взаимообусловленности уровня дегидрогеназной активности ила и показателей отдельных технологических параметров биологической очистки. Показано, что режим работы аэротенков (нагрузка на ил, доза активного ила и др.) и величина показателей исходной дегидрогеназной активности и дегидрогеназной активности этого же образца ила со слабо концентрированным раствором (ДАИН2О) связаны между собой и зависят от нагрузки на ил по органическим веществам. Полученные результаты исследования могут быть использованы для контроля биологического процесса очистки сточных вод.The biological method of wastewater treatment is a comprehensive multicomponent process the activities of the enzyme system being the key component of it. It is known that dehydrogenases have been one of the most important enzymes the ensure the biological process. The complicated mechanism of the action of enzymes has not been fully described so far however, in the practice of monitoring biological treatment processes, an indicator of the dehydrogenase activity of sludge is used. The research results provided for supplementing the available information with actual data on the interdependence of the level of dehydrogenase activity of sludge and indicators of individual process parameters of biological treatment. It was shown that the mode of operation of aeration tanks (organic matter load on sludge, dose of activated sludge, etc.) and the values of the initial dehydrogenase activity and dehydrogenase activity of the same sludge sample with weakly concentrated solution (DASН2О) are interconnected and depend on the organic load on sludge. The results of the study can be used to control the biological process of wastewater treatment.The biological method of wastewater treatment is a comprehensive multicomponent process the activities of the enzyme system being the key component of it. It is known that dehydrogenases have been one of the most important enzymes the ensure the biological process. The complicated mechanism of the action of enzymes has not been fully described so far however, in the practice of monitoring biological treatment processes, an indicator of the dehydrogenase activity of sludge is used. The research results provided for supplementing the available information with actual data on the interdependence of the level of dehydrogenase activity of sludge and indicators of individual process parameters of biological treatment. It was shown that the mode of operation of aeration tanks (organic matter load on sludge, dose of activated sludge, etc.) and the values of the initial dehydrogenase activity and dehydrogenase activity of the same sludge sample with weakly concentrated solution (DASН2О) are interconnected and depend on the organic load on sludge. The results of the study can be used to control the biological process of wastewater treatment.


1989 ◽  
Vol 21 (8-9) ◽  
pp. 805-814 ◽  
Author(s):  
F. R. Christensen ◽  
G. Holm Kristensen ◽  
J. la Cour Jansen

Experimental investigations on the kinetics of wastewater treatment processes in biofilms were performed in a laboratory reactor. Parallel with the kinetic experiments, the influence of the biofilm kinetics on the biofilm structure was studied at macroscopic and microscopic levels. The close interrelationship between biofilm kinetics and structural changes caused by the kinetics is illustrated by several examples. From the study, it is evident that the traditional modelling of wastewater treatment processes in biofilm reactors based on substrate removal kinetics alone will fail in many cases, due to the inevitable changes in the biofilm structure not taken into consideration. Therefore design rules for substrate removal in biofilms used for wastewater treatment must include correlations between the removal kinetics and the structure and development of the biological film.


1992 ◽  
Vol 26 (1-2) ◽  
pp. 407-415 ◽  
Author(s):  
D. A. Barton ◽  
J. J. McKeown ◽  
W. Chudyk

A model of organic compound removal by biological wastewater treatment processes receiving pulp and paper industry wastewaters has been developed and initial model verification performed at a single mill site. This paper presents the results of further model verification conducted at multiple mill sites, including replication of the original site. In addition, VOC losses at other unit processes are quantified. Activated sludge basin chloroform volatilization rates are predicted to within twelve percent of the measured rates. Predicted overall methanol removals are consistent with observed removals although difficulties encountered during off-gas sampling preclude determination of the extent of removal due to volatilization.


1998 ◽  
Vol 38 (2) ◽  
pp. 9-15 ◽  
Author(s):  
J. Guan ◽  
T. D. Waite ◽  
R. Amal ◽  
H. Bustamante ◽  
R. Wukasch

A rapid method of determining the structure of aggregated particles using small angle laser light scattering is applied here to assemblages of bacteria from wastewater treatment systems. The structure information so obtained is suggestive of fractal behaviour as found by other methods. Strong dependencies are shown to exist between the fractal structure of the bacterial aggregates and the behaviour of the biosolids in zone settling and dewatering by both pressure filtration and centrifugation methods. More rapid settling and significantly higher solids contents are achievable for “looser” flocs characterised by lower fractal dimensions. The rapidity of determination of structural information and the strong dependencies of the effectiveness of a number of wastewater treatment processes on aggregate structure suggests that this method may be particularly useful as an on-line control tool.


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