Reduction of the content of organic micropollutants in digested sludge by a post-aeration process - a full-scale demonstration

2000 ◽  
Vol 42 (9) ◽  
pp. 111-118 ◽  
Author(s):  
L. Knudsen ◽  
G. H. Kristensen ◽  
P. E. Jørgensen ◽  
S.-E. Jepsen
Keyword(s):  
Treatment Plant ◽  
Full Scale ◽  
Wastewater Sludge ◽  
Biological Degradation ◽  
Organic Micropollutants ◽  
Digested Sludge ◽  
Limit Values ◽  
Anaerobically Digested Sludge ◽  
Aeration Process ◽  
First Time

Surplus wastewater sludge reused for agricultural purposes must observe certain limit values with respect to different xenobiotic substances. The latest revision of the statutory order in Denmark includes for the first time a list of limit values on organic micropollutants in sludge. Four groups of micropollutants are included in the list (LAS, PAH, NPE, and DEHP). The limit values will be revised in June 2000, at which time up to 50% of the sludge used for agricultural purposes, will not comply with the standards. It has been observed that the level of organic micropollutants is much higher in anaerobically digested sludge than in aerobically stabilised sludge. This indicates that the organic micropollutants in question can be partly or fully degraded under aerobic conditions but not under anaerobic conditions. The observations have formed the basis of the development of a post-aeration process for biological degradation of organic micropollutants in anaerobically digested sludge with the aim of enabling continued reuse of the sludge for agricultural purposes. The process is presented in this paper together with a description of a full scale demonstration experience on a Danish wastewater treatment plant © 1999, IAWQ. Published by Elsevier Science Ltd.

Characterization of raw sludge, chemically modified sludge and anaerobically digested sludge in Hong Kong

1998 ◽  
Vol 38 (2) ◽  
pp. 25-32 ◽  
Author(s):  
C. W. Chu ◽  
C. S. Poon ◽  
R. Y. H. Cheung
Keyword(s):  
Hong Kong ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Chemical Properties ◽  
Primary Treatment ◽  
Digested Sludge ◽  
Total N ◽  
Chemically Modified ◽  
Anaerobically Digested Sludge

Chemically Enhanced Primary Treatment (CEPT) or Chemically Assisted Primary Sedimentation (CAPS) is being employed at the new sewage work on Stonecutters Island as part of the Strategic Sewage Disposal Scheme (SSDS) in Hong Kong. CAPS involves the use of chemical coagulants (such as lime or ferric chloride) to induce coagulation or flocculation and let these finely-divided particles form large aggregates (floc) so that they can settle out within a reasonable period of time. In this study, five sludge samples collected from different sewage treatment plants in Hong Kong were physically and chemically characterized. They were chemically modified sludge from Stonecutters Island (CAPS) raw sludge from Tai Po and Yuen Long Sewage Treatment Plant (STP) (rTP & rYL) and anaerobically digested sludge from Tai Po and Yuen Long STP (dTP & dYL). It was found that CAPS sludge was better than other 4 sludge samples in terms of settleability and dewaterability. CAPS sludge contained significant higher amounts (p<0.01) of extractable compounds than other sludges (except NO3− for dTP, NH4+ and PO43− for dYL). The concentration of total N and P in CAPS sludge were significantly higher (p<0.01) than other sludges (except dYL). The concentrations of total Cu, Pb, Ni, Cd, Cr and K in the CAPS sludge were also significantly higher (p<0.01) than other sludge samples. Most of the metals (Cr, Pb, Cr and Zn) in CAPS sludge were associated with the organically-bounded phase. It is concluded that there are significant differences in both physical and chemical properties between the chemically modified sludge and biological treated sludges.

scholarly journals Plant-wide modelling for assessment and optimization of upgraded full-scale wastewater treatment plant performance

2018 ◽  
Vol 13 (3) ◽  
pp. 566-582 ◽  
Author(s):  
Nadja Hvala ◽  
Darko Vrečko ◽  
Cirila Bordon
Keyword(s):  
Wastewater Treatment ◽  
Simulation Model ◽  
Wastewater Treatment Plant ◽  
Performance Indicators ◽  
Treatment Plant ◽  
Full Scale ◽  
Plant Performance ◽  
Limit Values ◽  
Reject Water ◽  
Integrate State

Abstract This paper presents the design of a plant-wide CNP (carbon-nitrogen-phosphorus) simulation model of a full-scale wastewater treatment plant, which will be upgraded for tertiary treatment to achieve compliance with effluent total nitrogen (TN) and total phosphorus (TP) limit values. The plant-wide model of the existing plant was first designed and extensively validated under long-term dynamic operation. The most crucial step was a precise characterization of input wastewater that was performed by extending the plant performance indicators both to a water line and sludge line and systematically estimating identifiable wastewater characterization parameters from plant-wide performance indicators, i.e. effluent concentrations, biogas and sludge production, and sludge composition. The thus constructed simulation model with standard activated sludge model (ASM2d) and anaerobic digestion model (MantisAD) overpredicted ortho-P and ammonia-N on the sludge line, indicating a need to integrate state-of-the-art physico-chemical minerals precipitation models to simulate plant-wide interactions more precisely. The upgraded plant with multimode anaerobic/anoxic/oxic configuration shows limited denitrification potential. Therefore, additional reject water treatment was evaluated to improve effluent TN and TP performance.

Total nitrogen removal from high-strength ammonia recycle stream using a single submerged attached growth bioreactor

2007 ◽  
Vol 55 (8-9) ◽  
pp. 59-65 ◽  
Author(s):  
A. Onnis-Hayden ◽  
P.B. Pedros ◽  
J. Reade
Keyword(s):  
Total Nitrogen ◽  
Nitrogen Removal ◽  
Removal Rate ◽  
Treatment Plant ◽  
High Strength ◽  
Nitrogen Loading ◽  
Digested Sludge ◽  
Attached Growth ◽  
Anaerobically Digested Sludge ◽  
Total Nitrogen Removal

An experimental study investigating the nitrogen removal efficiency from the recycle stream generated in the dewatering facility of the anaerobically digested sludge at the Deer Island wastewater treatment plant (WWTP) in Boston was conducted using a single submerged attached growth bioreactor (SAGB), designed for simultaneous nitrification and denitrification. The applied nitrogen loading to the reactor ranged from 0.7 to 2.27 kg-N/m3·d, and the corresponding total nitrogen (TN) removal rate ranged from 0.38 to 1.8 kg-N/m3·d. The observed nitrification rates varied from 0.42 kg-N/m3·d to 1.45 kg-N/m3·d with an ammonia load of 0.5 kg-N/m3·d and 1.8 kg-N/m3·d, respectively. An average nitrification efficiency of 91% was achieved throughout the experiment. Denitrification efficiency varied from 55%, obtained without any addition of carbon source, to 95% when methanol was added in order to obtain a methanol/nitrate ratio of about 3 kg methanol/kg NO3−-N.

Managing Change in an Environmentally Conscious Society: A Case Study, Gothenburg (Sweden)

1990 ◽  
Vol 22 (12) ◽  
pp. 45-56 ◽  
Author(s):  
P. Balmer ◽  
R. C. Frost
Keyword(s):  
Land Reclamation ◽  
Public Attitudes ◽  
Public Support ◽  
Treatment Plant ◽  
Digested Sludge ◽  
Environmentally Conscious ◽  
Managing Change ◽  
Underground Cavities ◽  
Anaerobically Digested Sludge

The treatment and disposal of sewage sludge in environmentally conscious societies is becoming increasingly problematical due, in large part, to public attitudes. Strategies have to be developed which either successfully defend existing routes or which manage changes that have public support. A case study of managing change at a large wastewater treatment plant, serving Gothenburg, Sweden, is presented. Three radically different alternatives to the current practice, of lime addition to dewatered raw sludge and disposal to land reclamation, were appraised to a common set of criteria and compared with the existing route. The options considered were incineration, drying of dewatered anaerobically digested sludge, and disposal of dewatered anaerobically digested sludge to underground cavities. An account is given of the public discussion meetings that were held at strategically important times, the views expressed at these being taken into account by GRYAAB's management board in their decision to opt for the disposal of sludge to underground cavities.

scholarly journals Integrated Membrane Process for the Treatment and Reuse of Residual Table Olive Fermentation Brine and Anaerobically Digested Sludge Centrate

Membranes ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 253
Author(s):  
Carlos Carbonell-Alcaina ◽  
Jose Luis Soler-Cabezas ◽  
Amparo Bes-Piá ◽  
María Cinta Vincent-Vela ◽  
Jose Antonio Mendoza-Roca ◽  
...  
Keyword(s):  
Organic Matter ◽  
Municipal Wastewater ◽  
Forward Osmosis ◽  
Treatment Plant ◽  
Oxygen Demand ◽  
Transmembrane Pressure ◽  
Municipal Wastewater Treatment ◽  
Digested Sludge ◽  
Anaerobically Digested Sludge ◽  
Table Olive

Management of wastewater is a major challenge nowadays, due to increasing water demand, growing population and more stringent regulations on water quality. Wastewaters from food conservation are especially difficult to treat, since they have high salinity and high organic matter concentration. The aim of this work is the treatment of the effluent from a table olive fermentation process (FTOP) with the aim of reusing it once the organic matter is separated. The process proposed in this work consists of the following membrane-based technologies: Ultrafiltration (UF) (UP005, Microdyn Nadir), Forward Osmosis (FO) (Osmen2521, Hydration Technology Innovation) and Nanofiltration (NF) (NF245, Dow). The FO process was implemented to reduce the salinity entering the NF process, using the FTOP as draw solution and, at the same time, to concentrate the centrate produced in the sludge treatment of a municipal wastewater treatment plant with the aim of obtaining a stream enriched in nutrients. The UF step achieved the elimination of 50% of the chemical oxygen demand of the FTOP. The UF permeate was pumped to the FO system reducing the volume of the anaerobically digested sludge centrate (ADSC) by a factor of 3 in 6.5 h. Finally, the ultrafiltrated FTOP diluted by FO was subjected to NF. The transmembrane pressure needed in the NF stage was 40% lower than that required if the ultrafiltration permeate was directly nanofiltered. By means of the integrated process, the concentration of organic matter and phenolic compounds in the FTOP decreased by 97%. Therefore, the proposed process was able to obtain a treated brine that could be reused in other processes and simultaneously to concentrate a stream, such as the ADSC.

Effect of daylight on regrowth of bacteria in anaerobically digested sludge

2010 ◽  
Vol 62 (2) ◽  
pp. 364-369 ◽  
Author(s):  
İrep Gözen ◽  
Banu Örmeci
Keyword(s):  
Clostridium Perfringens ◽  
Treatment Plant ◽  
Storage Period ◽  
Total Coliform ◽  
The Other ◽  
Masking Effect ◽  
Digested Sludge ◽  
Sludge Cake ◽  
Anaerobically Digested Sludge ◽  
Presence And Absence

This study investigated the regrowth of total coliform, Salmonella, and Clostridium perfringens in anaerobically digested sludge after centrifuge dewatering in the presence and absence of daylight. Sludge cake and centrate samples were collected from a treatment plant, and half of the samples was stored in daylight and the other half was stored in dark for three weeks. The bacteria levels in the cake and centrate samples were measured periodically throughout the storage period, and all three bacteria showed substantial regrowth. Presence of daylight increased the regrowth of Salmonella both in sludge cake and centrate, and increased the regrowth of total coliform in centrate. Salmonella exhibited the highest regrowth rate in cake among the three bacteria tested both in the presence and absence of light. Daylight did not appear to have a significant impact on the regrowth of Clostridium perfringens in cake and centrate, and on the regrowth of total coliform in cake. This might, however, be caused by the masking effect of the higher initial numbers of these bacteria in the samples. There is need for more research to thoroughly understand the effect of daylight on the regrowth of sludge bacteria.

Full-scale phosphorus recovery from digested wastewater sludge in Belgium – part II: economic opportunities and risks

2014 ◽  
Vol 71 (4) ◽  
pp. 495-502 ◽  
Author(s):  
Sam Geerts ◽  
Adrien Marchi ◽  
Marjoleine Weemaes
Keyword(s):  
Sensitivity Analysis ◽  
Financial Risk ◽  
Financial Incentive ◽  
Full Scale ◽  
Wastewater Sludge ◽  
Phosphorus Recovery ◽  
Digested Sludge ◽  
Positive Economic ◽  
Demonstration Plant ◽  
P Recovery

One of the options to recycle phosphorus (P) in the wastewater sector is to recover it as struvite crystals from digested sludge. Measurements on a full-scale demonstration plant in Leuven, Belgium, yielded a first indication of the profitability of struvite recovery, in function of different variables such as incoming PO43− concentration, MgCl2 dosing, improved dewaterability, etc. An uncertainty and sensitivity analysis was carried out. Although possible improvement in sludge dewaterability when recovering struvite from digested sludge has a positive economic amortization effect, it is at the same time the largest source of financial risk. A theoretical exercise showed that for struvite recovery from centrate, uncertainty would be lower, and the largest sensitivity would be attributed to ingoing PO43− concentration. Although struvite recovery from digested sludge is riskier, it is an investment with potentially a higher return than investment in struvite recovery from centrate. The article provides information for possible financial incentive schemes to support P-recovery.

Ferrrate(VI) and freeze-thaw treatment for oxidation of hormones and inactivation of fecal coliforms in sludge

2017 ◽  
Vol 75 (7) ◽  
pp. 1625-1632 ◽  
Author(s):  
James Diak ◽  
Banu Örmeci
Keyword(s):  
Wastewater Sludge ◽  
Fecal Coliforms ◽  
Second Phase ◽  
Potassium Ferrate ◽  
Digested Sludge ◽  
Freeze Thaw ◽  
Sludge Cake ◽  
Anaerobically Digested Sludge ◽  
Pre Treatment ◽  
The Individual

This study examined the individual and combined effects of potassium ferrate(VI) additions and freeze-thaw conditioning for the treatment and dewatering of wastewater sludge in cold climates, with particular focus on the inactivation of fecal coliforms and oxidation of estrogens, androgens, and progestogens. The first phase of the study evaluated the effects of potassium ferrate(VI) pre-treatment followed by freeze-thaw at −20 °C using a low (0.5 g/L) and high (5.0 g/L) dose of potassium ferrate(VI). The results showed that pre-treatment of anaerobically digested sludge with 5 g/L of potassium ferrate(VI) reduced the concentration of fecal coliforms in the sludge cake to below 100 MPN/g DS. The second phase evaluated the ability of ferrate(VI) to oxidise selected hormones in sludge. Anaerobically digested sludge samples were spiked with 10 different hormones: estrone (E1), 17α-estradiol, 17β-estradiol (E2), estriol (E3), 17α-ethinylestradiol (EE2), equilin, mestranol, testosterone, norethindrone and norgestrel in two groups of low (3–75 ng/mL) and high (12–300 ng/L) concentration ranges of hormones. The samples were treated with either 0.5 or 1.0 g/L of potassium ferrate(VI), and hormone concentrations were measured again after treatment. Potassium ferrate(VI) additions as low as 1.0 g/L reduced the concentration of estrogens in sludge. Potassium ferrate(VI) additions of 0.5 and 1.0 g/L were less effective at reducing the concentrations of androgens and progestogens. Increasing ferrate(VI) dose would likely result in more substantial decreases in the concentrations of fecal coliforms and hormones. The results of this study indicate that the combined use of freeze-thaw and ferrate(VI) has the potential to provide a complete sludge treatment solution in cold regions.

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