Biolixiviation des métaux lourds et stabilisation des boues d'épuration : essai en bioréacteur opéré en mode cuvée

1993 ◽  
Vol 20 (1) ◽  
pp. 57-64 ◽  
Author(s):  
R. D. Tyagi ◽  
J. F. Blais ◽  
N. Meunier ◽  
D. Kluepfel

A biological process of heavy metals solubilization and sewage sludge stabilization was studied in a batch reactor of 30-L capacity. The acclimatized leaching microflora was composed of two major groups of thiobacilli: less acidophilic and acidophilic. A batch time of 10 days allows a substantial metal solubilization: cadmium (100%), copper (80%), manganese (80%), nickel (46%), and zinc (100%). The bioleaching process also causes a significative decrease in sludge total suspended solids (25%) and volatile suspended solids (32%), and a considerable reduction (under the detection limit of 10 cfu∙mL−1) of indicator bacteria (total coliforms, fecal coliforms, fecal streptococci). After filtration or centrifugation of the leached sludge, the solubilized metals were precipitated by lime neutralization. The phosphorus and potassium sludge contents were not affected by bioleaching process. These results indicate that the process of sludge digestion and metal leaching can be conducted in parallel in the same reactor. Key words: sewage sludge, heavy metals, bioleaching, stabilization, thiobacilli, elemental sulfur.

2002 ◽  
Vol 45 (10) ◽  
pp. 269-274 ◽  
Author(s):  
N. Cabirol ◽  
M. Rojas Oropeza ◽  
A. Noyola

Anaerobic digestion of two types of waste sludge was applied in order to assess the suitability of thermophilic conditions for the stabilization of organic matter and removal of fecal coliforms and helminth eggs. Feeding sludge was taken from an activated sludge municipal facility (BS) and from an enhanced primary treatment municipal plant (EPT). As an accompanying experiment, mesophilic digesters were also operated. The four digesters (M1, M2, T1, T2) had a 5 litre volume and an egg shape. A highly stabilized material was obtained at both temperatures with BS type of sludge, taking the reduction of volatile fraction of suspended solids (%RVSS) as indicator (84% for M1 and 74% for T1). In general, EPT sludge was a more difficult substrate, if compared with BS sludge; thermophilic condition was better adapted than mesophilic for this kind of sludge. Satisfactory reductions on counts of fecal coliforms and helminth eggs were achieved under thermophilic digestion for both types of feeding sludge. T1 digester, fed with biological sludge, removed fecal coliforms below 1000 MPN/gTS and helminth eggs down to 0.28 HELarval/gTS, at an HRT of 20 days. As a general conclusion, anaerobic thermophilic digestion may be an appropriate option for sludge stabilization, in order to meet EPA Class A biosolids final disposal regulations. However, further research is needed in order to consistently remove helminth eggs and fecal coliforms from waste sludge at shorter hydraulic retention times.


2004 ◽  
Vol 50 (9) ◽  
pp. 205-211 ◽  
Author(s):  
J.Y. Wang ◽  
D.S. Zhang ◽  
O. Stabnikova ◽  
J.H. Tay

High content of heavy metals and presence of pathogens in the dewatered sewage sludge have been the main obstacles for land application of sewage sludge-made fertilizer. The aim of this study was to xamine the effects of the innovative electrokinetic (EK) technology on removal of heavy metals from sewage sludge, on the reduction of pathogens, and on sludge chemical characteristics. The results showed that the removal efficiencies for Zn, Cu, Ni, Cr, As and Pb were 94.9%, 95.4%, 89.7%, 67.8%, 31.2% and 18.7%, respectively. Acidification pretreatment of the dewatered sludge for 29 h decreased the content of heterotrophic bacteria from 1.5 × 108 c.f.u./g of wet sludge to 1.1 × 104 c.f.u./g of wet sludge. Although the initial content of total coliforms and fecal coliforms in sewage sludge were 5.8 × 105 c.f.u./g of wet sludge and 4.0 × 105 c.f.u./g of wet sludge, respectively, no viable cells were detected. Minor losses of K and N were detected, but the loss of P was found to be significant in EK treated sewage sludge. The treated sludge has technically considered as very stable based on the carbon dioxide evolution rate.


2001 ◽  
Vol 43 (2) ◽  
pp. 59-65 ◽  
Author(s):  
K. Kitada ◽  
A. Ito ◽  
K. Yamada ◽  
J. Aizawa ◽  
T. Umita

The utilization of indigenous sulfur-oxidizing bacteria and sulfur waste was investigated in order to remove heavy metals from anaerobically digested sewage sludge economically. Indigenous sulfur-oxidizing bacteria existing in anaerobically digested sewage sludge were activated by adding elemental sulfur to the sludge and then the bacteria were isolated. It was found that indigenous sulfur-oxidizing bacteria could utilize sulfur waste generated by desulfurization of digestion gas as a substrate. Then, biological leaching of heavy metals from anaerobically digested sewage sludge was carried out using indigenous sulfur-oxidizing bacteria and sulfur waste. By adding sulfur waste to sewage sludge, sulfuric acid was produced by the bacteria and the sludge pH decreased. Heavy metals in sewage sludge were effectively removed owing to the decrease of pH. The optimum amount of sulfur waste added to decrease the pH sufficiently was 5g/L when the sludge concentration was 2%. It was presented that the biological leaching of heavy metals from sewage sludge can be carried out in a closed system, where all required materials are obtained in a sewage treatment plant.


Membranes ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 722
Author(s):  
Robert Kowalik ◽  
Jolanta Latosińska ◽  
Monika Metryka-Telka ◽  
Rafał Porowski ◽  
Jarosław Gawdzik

Sewage sludge from sewage treatment plants has soil-forming and fertilising properties. However, sewage sludge cannot always be used in nature, including agriculture. One of the main reasons is the concentration of heavy metals. Sludge from wastewater treatment plants operating in MBR (membrane biological reactor) and SBR (sequential batch reactor) systems was analysed. Studies comparing the risk analysis of the natural use of sludge from MBR and SBR treatment plants were performed for the first time, due to the fact that more and more MBR plants, which are a BAT technology, are being developed in Poland, displacing the classical SBR plants. MBR technology uses a combination of activated sludge and filtration with microfiltration membranes. Wastewater treated in these reactors meets the highest quality standards, both in terms of physicochemical and microbiological aspects. This paper presents studies on the mobility of heavy metals in sewage sludge carried out using the BCR sequential extraction method. Geo-accumulation index (GAI), potential environmental risk index (ER), risk assessment code (RAC), and environmental risk determinant (ERD) were calculated. Heavy metals dominated the stable fractions in all cases. Furthermore, an increased content of copper and cadmium was observed in the MBR sludge. This fact is favourable in view of the efforts to eliminate heavy metals in the environment.


2013 ◽  
Vol 67 (11) ◽  
pp. 2488-2493 ◽  
Author(s):  
A. Ito ◽  
K. Yamada ◽  
N. Ishikawa ◽  
T. Umita

Microbial acidification of incinerated sewage sludge ash and dissolution of metals from the acidified ash were investigated using a semi-batch reactor at different solid retention times (SRTs). The average pH values ranged from 0.91 to 1.2 at SRTs longer than 10 days, whereas the reduction of SRT to 4 days resulted in an increase in the pH value to about 2. The dissolution efficiencies of Al, As, Cd, Cu and Mn were greater than 60% at a SRT of 4 days. Moreover, the effect of pH on precipitation of metals and P (dissolution of 80%) in the filtrate removed from the acidified sewage ash suspension, and the separation of phosphorus and the other metals in the filtrate using ethylenediaminetetraacetic acid (EDTA) or ferric ion, were examined. Although neutralisation of the filtrate to a pH of 5 simultaneously precipitated 100% of Al and 80% of P recovered from the acidified sewage ash, the addition of EDTA decreased their precipitation to 70 and 50%, respectively, at the same pH value, which would promote precipitation of P as calcium phosphate. Furthermore, neutralising to a pH of 2.5 after the addition of ferric ion precipitated P separately from Al and heavy metals.


2019 ◽  
Vol 11 (9) ◽  
pp. 281
Author(s):  
Geraldo R. Zuba Junio ◽  
Regynaldo A. Sampaio ◽  
Luiz A. Fernandes ◽  
Rodinei F. Pegoraro ◽  
Victor M. Maia ◽  
...  

The usage of sewage sludge in agriculture can increase the levels of heavy metals in the soil, compromising their use as fertilizer. The objective of this study was to evaluate the contamination of soil and pineapple by heavy metals after the application of treated sewage sludge by different forms in three orders of soils under greenhouse conditions. The treatments, in a factorial scheme 7 × 3 were distributed in a randomized complete block design with three replications, corresponding to seven fertilization management: soil without fertilization, chemical fertilization, fertilization with composted sludge sewage, fertilization with vermicompost sewage sludge, fertilization with solarized sewage sludge, fertilization as sewage sludge dried in a Bruthus-Albrecht rotary sludge dryer and fertilization with limed sludge sewage, combined with three orders of soils: Cambisol, Nitisol and Acrisol. The Zn, Cu, Cr, Pb, Ba, Cd, Ni, As and Se contents were analyzed in the soil, in the leaf of greater length (D leaf) and in the fruit pulp of the pineapple. The Acrisol provided more favorable conditions to the increase in the availability and absorption of Pb and As by D leaf and fruit of the pineapple. Fertilization with composted, vermicompost and solarized sewage sludge provided high levels of Pb, As, Zn in leaf D and in the pineapple fruit, relating the interference of sludge stabilization process with the absorption of metals by pineapple fruits.


1982 ◽  
Vol 11 (2) ◽  
pp. 182-186 ◽  
Author(s):  
W. E. Emmerich ◽  
L. J. Lund ◽  
A. L. Page ◽  
A. C. Chang

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