scholarly journals A new energy-positive technological approach for wastewater treatment and bioenergy generation using a photo anoxic baffled reactor (PABR)

2021 ◽  
Author(s):  
M. Hasan ◽  
Md. Khalekuzzaman ◽  
M. Alamgir ◽  
P. Datta ◽  
S. B. Kabir
Keyword(s):  
Wastewater Treatment ◽  
Oxygen Demand ◽  
Average Intensity ◽  
Sludge Sample ◽  
Bacterial Symbiosis ◽  
Technological Approach ◽  
Wide Range ◽  
Bioenergy Generation ◽  
New Energy ◽  
The Fourier Transform

AbstractThis study proposed a new energy-positive technological approach for wastewater treatment and bioenergy generation using an algal–bacterial symbiosis system in a photo anoxic baffled reactor (PABR). The PABR consisted of a sedimentation chamber, four regular baffled chambers, and two floated filter media chambers. The PABR was operated in the presence of natural sunlight with an average intensity of 30 µmoles/m2/s. A wide range of ORP (−215 to 255 mV) data suggested that a suitable environment condition existed in the PABR for photosynthesis, nitrification, and denitrification. Simultaneous nitrification/denitrification (SND) was observed in the first three chambers, and microbial assimilation was governed in the last four chambers. An average biochemical oxygen demand (BOD), NH3–N, total nitrogen (TN), and PO43− removal efficiencies were more than 88, 48, 36, and 42%, respectively. Moreover, hydrothermal liquefaction (HTL) was carried out for sludge and microalgae samples for bioenergy (e.g., biocrude and biochar) conversion, where the sludge sample containing microalgae and bacteria was collected from PABR and microalgae sample was collected from photobioreactor. Finally, the Fourier transform infrared spectroscopy (FTIR) analysis was done for both biocrude and biochar derived from sludge and microalgae samples, and it was suggested that the biocrude and biochar derived from sludge sample were better than that of microalgae sample.

scholarly journals Techno-Economic Analysis of Electrocoagulation on Water Reclamation and Bacterial/Viral Indicator Reductions of a High-Strength Organic Wastewater—Anaerobic Digestion Effluent

2020 ◽  
Vol 12 (7) ◽  
pp. 2697
Author(s):  
Sibel Uludag-Demirer ◽  
Nathan Olson ◽  
Rebecca Ives ◽  
Jean Pierre Nshimyimana ◽  
Cory A. Rusinek ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Anaerobic Digestion ◽  
Oxygen Demand ◽  
High Strength ◽  
Economic Assessment ◽  
Small Scale ◽  
Electrochemical Approach ◽  
Wide Range ◽  
Treatment Technologies ◽  
Small Footprint

This study investigated the use of iron and aluminum and their combinations as electrodes to determine the technically sound and economically feasible electrochemical approach for the treatment of anaerobic digestion effluent. The results indicated that the use of iron as anode and cathode is the most suitable solution among different electrode combinations. The reduction of turbidity, total chemical oxygen demand, total phosphorus, total coliforms, Escherichia coli, Enterococci, and phages in the reclaimed water were 99%, 91%, 100%, 1.5 log, 1.7 log, 1.0 log, and 2.0 log, respectively. The economic assessment further concluded that the average treatment cost is $3 per 1000 L for a small-scale operation handling 3000 L wastewater/day. This study demonstrated that the electrocoagulation (EC) is a promising technique for the recovery and reclamation of water from anaerobic digestion effluent. Even though its energy consumption is higher and the nitrogen removal is insufficient compared to some conventional wastewater treatment technologies, there are several advantages of the EC treatment, such as short retention time, small footprint, no mixing, and gradual addition of coagulants. These features make EC technology applicable to be used alone or combined with other technologies for a wide range of wastewater treatment applications.

scholarly journals A simple preparation route for polysilicate titanium salt from spent titanium solutions

2019 ◽  
Vol 80 (7) ◽  
pp. 1347-1356 ◽  
Author(s):  
Bin Xu ◽  
Yingjie Zhang ◽  
Xue Li ◽  
Yao Yao ◽  
Xuesong Huang ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Photoelectron Spectroscopy ◽  
Raw Materials ◽  
Oxygen Demand ◽  
Domestic Wastewater ◽  
Size Change ◽  
Floc Size ◽  
Molar Ratios ◽  
Wide Range ◽  
Titanium Salt

Abstract Polysilicate titanium salt (PST) is synthesized by using spent titanium solutions and polysilicic acid (PSiA) as raw materials. PSiA could improve the aggregation ability of titanium salt flocculants and also restrain the hydrolysis of Ti4+ to stabilize titanium salts. Meanwhile, replacing titanium salt with spent titanium solutions could reduce the cost of PST and solve the problem of wastewater treatment in the titanium industry, which makes valuable waste regeneration possible. Scanning electron microscopy (SEM) results show the morphology transformation (sheet, spheroid, and sphere) of PST with different Ti/Si molar ratios. The formation process of PST is analyzed by Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). This study investigates the effect of Ti/Si molar ratios on PST flocculation performance in humic–kaolin water and actual domestic wastewater treatment. The in situ floc size change of PST is measured by laser particle size analyzer in humic–kaolin water treatment. Additionally, the performance of PST is comprehensively evaluated on flocculation and sedimentation ability, rapid sweep netting ability and stability. In short, the prepared PST in this study is suitable for treating wastewater with high turbidity and chemical oxygen demand (COD) in a wide range of pH values.

scholarly journals Chemical and Electro-coagulation Techniques in Coagulation-Floccculation in Water and Wastewater Treatment- A Review

2013 ◽  
Vol 9 (3) ◽  
pp. 1988-1999
Author(s):  
Ukiwe L.N ◽  
Ibeneme S.I ◽  
Duru C.E ◽  
Okolue B.N ◽  
Onyedika G.O ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Colloidal Particles ◽  
Oxygen Demand ◽  
Biological Oxygen Demand ◽  
Water And Wastewater Treatment ◽  
Iron Salts ◽  
Wide Range ◽  
Water And Wastewater ◽  
Design Mechanism ◽  
Electro Coagulation

Chemical and electrocoagulation are widely used coagulation methods employed in water and wastewater treatment. Both coagulation processes are effective in removing a wide range of impurities which include dissolved organic matter in form of chemical and biological oxygen demand, pathogens, oils, and colloidal particles as well as heavy metals. The present review has revealed that the mode of action of both coagulation methods is based on charge neutralization and floc formation. The effectiveness of both coagulation techniques depend on factors such as pH, coagulation dose, coagulant type, current density, applied voltage, water and wastewater  type, type of electrode, as well as size and number of electrodes. The commonly used chemical coagulants are inorganic coagulants based on aluminum and iron salts. However, there have been considerable successes in the development of pre-hydrolyzed inorganic coagulants which have the added advantage over traditional inorganic coagulants in that they function well over a wide range of pH and water temperatures. Electrocoagulation has been proposed as an alternative method to chemical coagulation because it is environmental friendly and cheap to operate. Nonetheless, most researchers are of the opinion that there are still some uncertainties regarding the understanding of its optimal performance and design mechanism.

scholarly journals Long-term operation of a novel electrically-enhanced biomass concentrator reactor for wastewater treatment

2018 ◽  
Vol 77 (8) ◽  
pp. 2036-2044 ◽  
Author(s):  
D. Cecconet ◽  
A. Callegari ◽  
A. G. Capodaglio
Keyword(s):  
Wastewater Treatment ◽  
Energy Efficient ◽  
Oxygen Demand ◽  
Urban Wastewater ◽  
Term Operation ◽  
Wide Range ◽  
Biomass Retention ◽  
Electrically Enhanced ◽  
Urban Wastewater Treatment

Abstract Membrane biological reactors (MBRs) are a key technology in wastewater treatment nowadays. However, due to their high construction cost and energetic requirements, alternatives based on the same principle of biomass retention have been designed and operated. Amongst these, biomass concentrator reactors (BCRs), using a coarser filter medium instead of a membrane, have shown to be able to remove a wide range of contaminants from wastewater and groundwater. A new BCR-derived technology enhanced with an electric field, called the electrically-enhanced biomass concentrator reactor (E2BCR), was designed and tested for urban wastewater treatment at different organic loads for a period of 180 days. The electrically-enhanced reactor showed better chemical oxygen demand (COD) removal performances than a non-enhanced control reactor (92.4% and 83.6% respectively) thanks also to electrocoagulation effects, and a lower fouling tendency, and proved to be more energy efficient in comparison with the control reactor in terms of energy consumption per mass of COD removed.

Nanofiltration of endocrine disrupting compounds

2003 ◽  
Vol 3 (5-6) ◽  
pp. 321-327 ◽  
Author(s):  
M. Gallenkemper ◽  
T. Wintgens ◽  
T. Melin
Keyword(s):  
Wastewater Treatment ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Endocrine Disrupting Compounds ◽  
Municipal Wastewater Treatment ◽  
Water And Wastewater Treatment ◽  
Wide Range ◽  
Endocrine Disrupting ◽  
Municipal Wastewater Treatment Plants ◽  
Set Up

Endocrine disrupting compounds can affect the hormone system in organisms. A wide range of endocrine disrupters were found in sewage and effluents of municipal wastewater treatment plants. Toxicological evaluations indicate that conventional wastewater treatment plants are not able to remove these substances sufficiently before disposing effluent into the environment. Membrane technology, which is proving to be an effective barrier to these substances, is the subject of this research. Nanofiltration provides high quality permeates in water and wastewater treatment. Eleven different nanofiltration membranes were tested in the laboratory set-up. The observed retention for nonylphenol (NP) and bisphenol A (BPA) ranged between 70% and 100%. The contact angle is an indicator for the hydrophobicity of a membrane, whose influence on the permeability and retention of NP was evident. The retention of BPA was found to be inversely proportional to the membrane permeability.

Microplastic contamination in a conventional wastewater treatment plant in Thailand

2021 ◽  
pp. 0734242X2098205
Author(s):  
Katekanya Tadsuwan ◽  
Sandhya Babel
Keyword(s):  
Wastewater Treatment ◽  
Wastewater Treatment Plant ◽  
Environmental Concern ◽  
Liquid Fraction ◽  
Treatment Plant ◽  
Dry Weight ◽  
Plastic Waste ◽  
Sludge Sample ◽  
Global Environmental ◽  
Urban Wastewater Treatment

Plastic waste has become a global environmental concern. One type of plastic waste is microplastics (MPs), which can spread easily in the environment. Wastewater effluent is one of the land-based sources of MPs. This study investigates the amount of microplastic (MP) pollution in an urban wastewater treatment plant (WWTP) in Thailand. Water samples were collected and examined to find the types, morphology and sources of MPs. Wastewater was filtered through a set of sieves ranging from 5 mm to 0.05 mm. Sludge samples were also collected to find the potential risk from the application of dried sewage sludge. Fourier-transform infrared spectroscopy (FTIR) was used to confirm the types of MPs. The amount of MPs in the influent was 26.6 ± 11.8 MPs/L. More than one-third of MP particles were removed after a grit trap, followed by 14.24% removal in the secondary treatment. If the peak flow rate of the WWTP is reached, 2.32 × 109 MP particles can be released daily. The amount of MPs in a sludge sample was 8.12 ± 0.28 × 103 particles/kg dry weight. Dry sludge is one of the potential sources of MP contamination in agricultural soil. Most MPs in the liquid fraction and sludge sample were fibres. Results from FTIR analysis showed that the major types of MPs in the WWTP were polyester fibres, followed by polypropylene, polyethylene, silicone polymer and polystyrene. This finding indicates that a conventional WWTP may act as a path by which MPs enter the environment.

scholarly journals A Cyanobacteria-Based Biofilm System for Advanced Brewery Wastewater Treatment

2020 ◽  
Vol 11 (1) ◽  
pp. 174
Author(s):  
Konstantinos P. Papadopoulos ◽  
Christina N. Economou ◽  
Athanasia G. Tekerlekopoulou ◽  
Dimitris V. Vayenas
Keyword(s):  
Wastewater Treatment ◽  
Biomass Production ◽  
Low Cost ◽  
Oxygen Demand ◽  
Dry Weight ◽  
Surface Hydrophobicity ◽  
Reactor Performance ◽  
Brewery Wastewater ◽  
Kjeldahl Nitrogen ◽  
Supporting Materials

Algal/cyanobacterial biofilm photobioreactors provide an alternative technology to conventional photosynthetic systems for wastewater treatment based on high biomass production and easy biomass harvesting at low cost. This study introduces a novel cyanobacteria-based biofilm photobioreactor and assesses its performance in post-treatment of brewery wastewater and biomass production. Two different supporting materials (glass/polyurethane) were tested to investigate the effect of surface hydrophobicity on biomass attachment and overall reactor performance. The reactor exhibited high removal efficiency (over 65%) of the wastewater’s pollutants (chemical oxygen demand, nitrate, nitrite, ammonium, orthophosphate, and total Kjeldahl nitrogen), while biomass per reactor surface reached 13.1 and 12.8 g·m−2 corresponding to 406 and 392 mg·L−1 for glass and polyurethane, respectively, after 15 days of cultivation. The hydrophilic glass surface favored initial biomass adhesion, although eventually both materials yielded complete biomass attachment, highlighting that cell-to-cell interactions are the dominant adhesion mechanism in mature biofilms. It was also found that the biofilm accumulated up to 61% of its dry weight in carbohydrates at the end of cultivation, thus making the produced biomass a suitable feedstock for bioethanol production.

Savings with upgraded performance through improved activated sludge denitrification in the combined activated sludge–biofilter system of the Southpest Wastewater Treatment Plant

2008 ◽  
Vol 57 (8) ◽  
pp. 1287-1293 ◽  
Author(s):  
A. Jobbágy ◽  
G. M. Tardy ◽  
Gy. Palkó ◽  
A. Benáková ◽  
O. Krhutková ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Activated Sludge ◽  
Wastewater Treatment Plant ◽  
Biological Treatment ◽  
Treatment Plant ◽  
Oxygen Demand ◽  
Process Efficiency ◽  
Initial Value ◽  
Initial Profile ◽  
Biological Treatment System

The purpose of the experiments was to increase the rate of activated sludge denitrification in the combined biological treatment system of the Southpest Wastewater Treatment Plant in order to gain savings in cost and energy and improve process efficiency. Initial profile measurements revealed excess denitrification capacity of the preclarified wastewater. As a consequence, flow of nitrification filter effluent recirculated to the anoxic activated sludge basins was increased from 23,000 m3 d−1 to 42,288 m3 d−1 at an average preclarified influent flow of 64,843 m3 d−1, Both simulation studies and microbiological investigations suggested that activated sludge nitrification, achieved despite the low SRT (2–3 days), was initiated by the backseeding from the nitrification filters and facilitated by the decreased oxygen demand of the influent organics used for denitrification. With the improved activated sludge denitrification, methanol demand could be decreased to about half of the initial value. With the increased efficiency of the activated sludge pre-denitrification, plant effluent COD levels decreased from 40–70 mg l−1 to < 30–45 mg l−1 due to the decreased likelihood of methanol overdosing in the denitrification filter

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