scholarly journals Treatment of tannery wastewater for reuse by physico-chemical processes and a membrane bioreactor

2016 ◽  
Vol 7 (4) ◽  
pp. 420-428 ◽  
Author(s):  
J. Fettig ◽  
V. Pick ◽  
M. Oldenburg ◽  
N. V. Phuoc

Treatment of wastewater from a tannery in Greater Ho Chi Minh City (Vietnam) was investigated on a pilot scale. After pre-treatment by the tannery that included batch-coagulation and sedimentation, the wastewater was treated by dissolved air flotation, a membrane bioreactor (MBR) and granular activated carbon (GAC) for polishing the MBR effluent. The average removal efficiency for organic substances in the MBR was 81% while total nitrogen could only be removed by 36%. The performance of the GAC column could be successfully predicted using adsorption parameters determined in laboratory experiments. A larger proportion of the organics in the MBR effluent was only weakly adsorbable, therefore the usable carbon capacity was limited as confirmed by the modelling approach. The results were used to outline the size of a technical plant with a volumetric loading rate of 3 kg COD/(m3*d) for the MBR and a specific carbon demand of about 1.8 kg/m3.

2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Alok Dhaundiyal ◽  
Divine Atsu ◽  
Laszlo Toth

Abstract Background Biomass pre-treatment is gaining attention as a standalone process to improve the qualitative aspect of the lignocellulosic material. It has been gaining ground in the power station by replacing the coal with the pre-treated biomass. In this context, this paper enlightens the operating condition of carrying out the torrefaction so that the process can be made relatively more effective. The influence of physico-chemical characteristics on the heat of reaction of pyrolysis reactions, mass loss and temperature regimes are evaluated by thermogravimetry of the pre-treated samples of the pinecone; whereas, the structural transformation in the basic constituents is determined via knowing the fractional change in cellulose, hemicellulose and acid-insoluble lignin contents of the pine cone. The thermogravimetric (TGA) and differential thermal analysis (DTA) were performed to determine the physical as well as the thermal behaviour of the thermally processed biomass. The samples had undergone thermal decomposition at heating rates of 5 °C min−1, 10 °C min−1 and 15 °C min−1. Nitrogen gas was used as a purge gas for the pyrolysis of the pre-treated samples. The volumetric rate of 200 ml min−1 was pre-set for the thermal decomposition of the samples at 600 °C; whereas, the selected torrefaction temperature range varied from 210 to 250 °C. Results The heat of reaction for the pre-treated samples was found to vary from 1.04 to 1.52 MJ kg−1; whereas, it was 0.91–1.54 MJ kg−1 for the raw samples. The total annual production cost of processing 3.6 Mg of fuel in a year at a pilot scale was $ 36.72; whereas, the fiscal burden per kilogram of fuel during thermal degradation of the processed fuel was reduced by 0.08–1.5ȼ. The entropy of the system decreased with an increasing ramp rate. The exergetic gain in the system increased by 1–2%. The loss of energy during the energy-intensive processing of the pre-treated fuel was relatively low at a heating rate of 5 °C min−1. Conclusion By the physico-chemical assessment, it was determined that pinecones required the highest torrefaction temperature and time to provide the upgraded pinecones. It was concluded that the duration of the torrefaction should be at least 15 min for a temperature of 250 °C so that the chemical exergy of the system, energy yield and the energy density of the processed material are qualitatively improved. The volatile and ash contents were noticed to decrease during the torrefaction process. The least fractional change in the volatile content was estimated at 210 °C for a torrefaction time of 15 min; whereas, the ash content was minimum at 210 °C for a torrefaction time of 5 min.


2016 ◽  
Vol 6 (4) ◽  
pp. 495-504 ◽  
Author(s):  
Hussein I. Abdel-Shafy ◽  
Mona S. M. Mansour

The present study aims to investigate the efficiency of integrated effective microorganisms (EM) and membrane bioreactor (MBR) for eliminating pharmaceutical active compounds (PhACs) from urine. Natural urine was separated using a ‘diversion toilet’. The toilet users were under medication with some pharmaceuticals, namely levofloxacine (LEF), ibuprofen (IBP) and atorvastatin (ATV). For correlation, three MBR pilot-scale sequences were examined. In Sequence 1, the MBR was used without pre-treatment. In Sequence 2, EM was added as pre-treatment in the mixing tank. The effluent was further treated with the MBR. In Sequence 3, EM was added directly to the activated sludge of the MBR. The results showed that Sequence 1 could decrease the PhACs from 10 mg/L to 1.5 mg/L, 0.5 mg/L and 0.9 mg/L for LEF, IBP and ATV, respectively. Sequence 2 exhibited remarkable improvement in PhACs removal. The overall residual concentration reached 0.7, 0.13 and 0.28 mg/L for LEF, IBP and ATV, successively. Applying Sequence 3 gives higher removal efficiency, where the residual concentration of LEF, IBP and ATV decreased to 0.50 mg/L, 0.10 mg/L and 0.22 mg/L, respectively. It was concluded that the contaminated urine was efficiently treated by adding EM directly to the activated sludge of the MBR, and the treated urine can be safely used as fertilizer.


1994 ◽  
Vol 29 (9) ◽  
pp. 205-212 ◽  
Author(s):  
B. Kasapgil ◽  
G. K. Anderson ◽  
O. Ince

Implementation of the EC Directive on Urban Wastewater Treatment has led to the introduction of more stringent discharge standards being imposed by the Regulating Agencies in the United Kingdom. It is for this reason that this investigation into the pre-treatment of a dairy wastewater prior to aerobic biological treatment was carried out. In order to upgrade the existing treatment plant at a local dairy a Dissolved Air Flotation (DAF) and an anaerobic digestion system as pre-treatment process were studied at pilot - scale. Results obtained from this study showed that the existing aerobic biological treatment plant failed to achieve both the present consent conditions and those required in 1995. It was shown that an anaerobic filter would enable the plant to meet the discharge standards proposed by the National Rivers Authority but due to the configuration of the land available for new works it is recommended that the existing aerobic biological filter be replaced by an activated sludge system. It is anticipated that such a system would reduce the final effluent COD to less than 125 mg/l.


2012 ◽  
Vol 7 (4) ◽  
Author(s):  
Tony Amato ◽  
Kuem-Seo Park ◽  
Wonkyu Yim ◽  
Tschungil Kim

The purpose of this paper is to present an overview of the design for both the full scale and pilot scale seawater reverse osmosis (SWRO) pre-treatment plant comprising Enflo-DAF™ dissolved air flotation (DAF) technology and dual media filtration (DMF) proposed and operating respectively at Ras Al Khair site in Saudi Arabia. The application of both DAF and DMF in the municipal water industry is regarded as well established; however the application of DAF to the treatment of seawater particularly at elevated temperatures and which is also prone to Red Tide or severe algae events is relatively new and there is a limited amount of experience in this area.


1998 ◽  
Vol 37 (8) ◽  
pp. 145-152 ◽  
Author(s):  
Milenko Roš ◽  
Anton Gantar

The leather industry is well known as a high consumer of water (30 to 80 m3 for 1 ton of processed raw skins). At the same time this industry is known for the high specific pollution of wastewater. The main characteristics of tannery wastewater are: high salinity, high organic loading (COD, BOD5), high content of ammonia and organic nitrogen, and presence of specific pollutants (sulphide, chromium). The largest Slovenian tannery (IUV Vrhnika) processing 40 to 50 t of pig skins daily has a good system of physico-chemical pre-treatment of their wastewater (coagulation and flocculation with Al-sulfate and anionic polyelectrolyte). In pre-treatment, about 60% of organic substances are removed (COD and BOD5) and above 95% of sulfide and chromium. Concerning Slovenian regulations and taking into consideration the fact that this tannery is located on the relatively small and slowly running river Ljubljanica such pre-treatment is not sufficient. The company would like to supplement pre-treatment with biological treatment. Laboratory and pilot scale feasibility experiments including conventional biological treatment with activated sludge and combined anaerobic-anoxic-aerobic treatment with fixed biomass using mechanical pretreated wastewater and pretreated wastewater with flotation were performed. It became clear that effective biological treatment requires long retention times (several days) for applicable effluent.


2002 ◽  
Vol 2 (3) ◽  
pp. 159-168 ◽  
Author(s):  
V. Gitis ◽  
R.C. Haught ◽  
R.M. Clark ◽  
E. Radha Krishnan

Pilot-scale experiments were conducted to investigate removal of Cryptosporidium parvum by contact granular filtration. The research demonstrated enhanced removal of Cryptosporidium parvum in the presence of kaolin particles. This is believed to be due electrostatic adhesion of Cryptosporidium parvum oocysts to the kaolin clay particles. The elementary physico-chemical interactions between filter granules and suspension particles will be discussed. This innovative concept was successfully implemented to reduce the ripening sequence of subsequent filtration experimental test runs by the addition of large surface area particles to slurry of kaolin and Cryptosporidium parvum in surface water.


1998 ◽  
Vol 37 (2) ◽  
pp. 35-42 ◽  
Author(s):  
M. J. Bauer ◽  
R. Bayley ◽  
M. J. Chipps ◽  
A. Eades ◽  
R. J. Scriven ◽  
...  

Thames Water treats approximately 2800Ml/d of water originating mainly from the lowland rivers Thames and Lee for supply to over 7.3million customers, principally in the cities of London and Oxford. This paper reviews aspects of Thames Water's research, design and operating experiences of treating algal rich reservoir stored lowland water. Areas covered include experiences of optimising reservoir management, uprating and upgrading of rapid gravity filtration (RGF), standard co-current dissolved air flotation (DAF) and counter-current dissolved air flotation/filtration (COCO-DAFF®) to counter operational problems caused by seasonal blooms of filter blocking algae such as Melosira spp., Aphanizomenon spp. and Anabaena spp. A major programme of uprating and modernisation (inclusion of Advanced Water Treatment: GAC and ozone) of the major works is in progress which, together with the Thames Tunnel Ring Main, will meet London's water supply needs into the 21st Century.


2000 ◽  
Vol 42 (10-11) ◽  
pp. 371-374 ◽  
Author(s):  
S. Araki ◽  
J. M. González ◽  
E. de Luis ◽  
E. Bécares

The viability of Parascaris equorum eggs was studied in two experimental pilot-scale high-rate algal ponds (HRAPs) working in parallel with 4 and 10 days hydraulic retention time respectively. Semi-permeable bags of cellulose (15000 daltons pore size) were used to study the effect of physico-chemical conditions on the survival of these helminth eggs. Three thousand eggs were used in each bag. Replicates of these bags were submerged for 4 and 10 days in the HRAPs and egg viability was compared with that in control bags submerged in sterile water. After 4 days exposure, 60% reduction in viability was achieved, reaching 90% after 10 days, much higher than the 16% and 25% found in the control bags for 4 and 10 days respectively. Ionic conditions of the HRAP may have been responsible for up to 50–60% of the egg mortality, suggesting that mortality due to the ionic environment could be more important than physical retention and other potential removal factors.


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