Importance of microbial adaptation for concentrate management in wastewater reuse process

2018 ◽  
Vol 30 (4) ◽  
pp. 719-731 ◽  
Author(s):  
Chungman Moon ◽  
Yongtae Ahn ◽  
Tae-Jin Lee ◽  
Yuhoon Hwang

Wastewater reuse has gained attention as an alternative and sustainable water resource. Reverse osmosis has been widely applied for wastewater reuse; however, generation of concentrate stream is the main drawback. Concentrate stream contains high concentrations of contaminants, and therefore, it should be properly treated prior to being discharged into a water body. Several technologies have been suggested for concentrate management, but the most common option is returning this stream to a wastewater treatment plant where a wastewater reuse plant is located. In this study, we investigated the feasibility of concentrate management by returning the concentrate to a wastewater treatment facility as a part of influent. The characteristics of the concentrate were extensively monitored, and it was verified that it contained high concentrations of salt and hardly biodegradable organics, which impede their application in biological wastewater treatment processes. The effect of seeding sludge was investigated using two different types of seeding sludge, adapted and unadapted. The adapted sludge taken at the wastewater treatment plant located at the wastewater reuse facility showed much better performance in terms of organic and nutrients removal. Moreover, the performance was recovered by a few days of additional adaptation time. However, the seeding sludge taken from another wastewater treatment plant (unadapted) showed poor performance due to different influent characteristics, especially salt concentration. Therefore, it could be concluded that the microbial adaptation step is very important for effective concentrate treatment when it is being returned to a wastewater plant as influent.

1999 ◽  
Vol 40 (4-5) ◽  
pp. 99-105 ◽  
Author(s):  
A. Lopez ◽  
G. Ricco ◽  
R. Ciannarella ◽  
A. Rozzi ◽  
A. C. Di Pinto ◽  
...  

Among the activities appointed by the EC research-project “Integrated water recycling and emission abatement in the textile industry” (Contract: ENV4-CT95-0064), the effectiveness of ozone for improving the biotreatability of recalcitrant effluents as well as for removing from them toxic and/or inhibitory pollutants has been evaluated at lab-scale. Real membrane concentrates (pH=7.9; TOC=190 ppm; CDO=595 ppm; BOD5=0 ppm; Conductivity=5,000 μS/cm; Microtox-EC20=34%) produced at Bulgarograsso (Italy) Wastewater Treatment Plant by nanofiltering biologically treated secondary textile effluents, have been treated with ozonated air (O3conc.=12 ppm) over 120 min. The results have indicated that during ozonation, BOD5 increases from 0 to 75 ppm, whereas COD and TOC both decrease by about 50% and 30 % respectively. As for potentially toxic and/or inhibitory pollutants such as dyes, nonionic surfactants and halogenated organics, all measured as sum parameters, removals higher than 90% were achieved as confirmed by the complete disappearance of acute toxicity in the treated streams. The only ozonation byproducts searched for and found were aldehydes whose total amount continuously increased in the first hour from 1.2 up to 11.8 ppm. Among them, formaldehyde, acetaldehyde, glyoxal, propionaldehyde, and butyraldehyde were identified by HPLC.


Author(s):  
T.D.C. Pushpakumara ◽  
◽  
W.G.T. Sandakelum ◽  

The use of sludge as fertilizers helps to the recycling of nutrients to the environment due to its beginning from wastewater and therefore relatively high content of nutrients and organic matter. However, wastewater does also contain hazardous compounds like heavy metals and micro pollutants which eventually are separated to the sludge during the treatment processes at the wastewater treatment plant. In order to improve the sludge quality, source tracking is a relatively cheap and effective way to find and eliminate hazardous compounds and prevent them from ending up in the sludge. The aim with this thesis was to investigate the fertilizer potential in sludge from wastewater treatment plant. The sludge is analyzed in terms of nutrient and heavy metal contents as well as physiochemical parameters. In order to determine the potential as fertilizer, the quality of the sludge is compared with other fertilizer alternatives, other sludge types and regulations for sludge use in agriculture. The work with sludge quality improvements in Gaborone is also investigated. Sludge from different stages along the treatment processes were collected in order to see differences in quality related to the treatment. The results shows that the samples of primary an aerobically treated sludge tend to have higher heavy metal content than the secondary sludge. The quality of the dry sludge samples indicates lower nutrient content than both the primary and secondary sludge, but similar heavy metal content. The analysis of dry sludge from indicates a low nutrient value and high heavy metal content in comparison to other selected fertilizer options and sludge from other. The processes for removal of nutrients from the wastewater are an important factor for the nutrient content in the sludge. Keywords wastewater; fertilizers; nutrients; sludge treatment


2014 ◽  
Vol 21 (2) ◽  
pp. 255-268 ◽  
Author(s):  
Sebastian Werle ◽  
Mariusz Dudziak

Abstract Municipal wastewater treatment results in the production of large quantities of sewage sludge, which requires proper environmentally accepted management before final disposal. Sewage sludge is a by-product of current wastewater treatment technologies. Sewage sludge disposal depends on the sludge treatment methods used in the wastewater treatment plant (anaerobic or aerobic digestion, drying, etc.). Taking into consideration presented given this information, a study concerning the effects of wastewater treatment processes and sewage sludge drying method on the sewage sludge gasification gas parameters was performed. Gasification is a prospective alternative method of sludge thermal treatment. For the purpose of experimental investigations, a laboratory fixed bed gasifier installation was designed and built. Two types of sewage sludge feedstock, SS1 and SS2, were analyzed. Sewage sludge SS1 came from a wastewater treatment plant operating in the mechanical and biological system while sewage sludge SS2 was collected in a mechanical, biological and chemical wastewater treatment plant with simultaneous phosphorus precipitation. The sludge produced at the plants was subject to fermentation and then, after being dehydrated, dried in a cylindrical drier on shelves heated up to 260ºC (sewage sludge SS1) and using hot air at a temperature of 150ºC in a belt drier (sewage SS2). The analysis shows that the sewage sludge properties strongly depend on the wastewater sources and the wastewater treatment processes. The gasification results, presented as a function of the amount of gasification agent, show that the greater oxygen content of SS1 caused a reduction in the reaction temperature. Paradoxically, this effect caused an increase in the quantity of combustible components in the gas. As expected, increasing the air flow rate caused a decrease in the heating value of the gas produced. A higher amount of oxidizer increases the amounts of noncombustible species and the volumetric fraction of nitrogen, thus reducing the heating value of the obtained gas. The higher hydrogen content in SS1 affects the gasification gas composition. As a result, combustible components are the majority of the syngas.


2016 ◽  
Vol 18 (4) ◽  
pp. 728-733 ◽  

<p>Odours discharged from wastewater treatment plants generally cause severe damage to locals. When facility odors affect air quality and cause citizen complaints, an investigation of those odours may require using standardized scientific methods. Odour intensity is one of the main odour characterization parameter, and represents an important sensory indicator of environmental odours.</p> <p>Presently, different international standards have been developed for the measurement of odours. Main consolidated methods are the measurement of odour index assessed by panelists, standardized in Japan and developed there more than 40 years ago; and the measured of odour concentration by dynamic olfactometer according to European standard EN13725:2003.</p> <p>In this study odour samples were collected on a municipal wastewater treatment plant to investigate the relationship between odour index assessed by Japanese standard methods and odour concentration measured with dynamic olfactometry. A monthly sampling and relative odour measurement were carried out for consecutive 8 months at the Laboratory of the Sanitary Environmental Engineering Division (SEED) at the University of Salerno (Italy).</p> <p>Results show a strong linear correlation between the two investigated odour measurement methods, in the case of the measurement of high concentrations. While at lower odour concentrations were observed a difference between the two methods.</p>


2008 ◽  
Vol 58 (10) ◽  
pp. 2001-2008 ◽  
Author(s):  
Sílvia C. Oliveira ◽  
Marcos von Sperling

The paper analyses the capability of 166 full-scale wastewater treatment plants operating in Brazil, in order to achieve different quality targets for wastewater discharge. These targets cover a wide range of possible situations, reflecting usual practices adopted worldwide. Six different treatment processes have been investigated: septic tank + anaerobic filter, facultative pond, anaerobic pond + facultative pond, activated sludge, UASB reactors alone, UASB reactors followed by post-treatment. The parameters investigated were: BOD, COD, suspended solids, total nitrogen, total phosphorus and thermotolerant coliforms. Most technologies showed a poor performance, and some of them were not capable to achieve even relaxed standards. The paper presents elements for setting up discharge standards in developing countries, based either on values that may be achieved by treatment processes commonly applied or on best available technologies.


Water ◽  
2018 ◽  
Vol 10 (7) ◽  
pp. 922 ◽  
Author(s):  
Verlicchi Paola ◽  
Al Mustafa ◽  
Zanni Giacomo

The study deals with the evaluation of the recreational benefit of a reclaimed water reuse project in the municipality of Ferrara, north Italy, by means of the contingent valuation method. It also provides an analysis of the public acceptance of the project, determined by eliciting the willingness of the local people to contribute to the realization of this project in monetary terms (their willingness to pay). The project involves the upgrade of the existing wastewater treatment plant by conventional (rapid sand filters) and natural (constructed wetland) treatments. The latter will be constructed within the urban park surrounding the wastewater treatment plant area and will combine the objectives of both wastewater treatment with recreational services, since they will create equipped green areas open to the public. The study is based on the answers provided by 400 respondents, who are residents in the four districts of the municipality of Ferrara. It emerges that willingness to pay is strongly influenced by the socio-economic characteristics of the respondents, with an amount on average of 48 €/family.


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