scholarly journals Treatment of Sewage Using a Constructed Soil Rapid Infiltration System Combined with Pre-Denitrification

2018 ◽  
Vol 15 (9) ◽  
pp. 2005 ◽  
Author(s):  
Wenlai Xu ◽  
Jinyao Chen ◽  
Yue Jian ◽  
Zhicheng Pan ◽  
Zishen Mou
Keyword(s):  
Carbon Source ◽  
Removal Rate ◽  
Oxygen Demand ◽  
The Other ◽  
Small Scale ◽  
Reflux Ratio ◽  
Activated Sludge Process ◽  
Hydraulic Load ◽  
Aerobic Nitrification ◽  
Denitrification Process

The activated sludge process of the anaerobic/oxic (A/O) process has a good denitrification performance because it can make full use of the carbon source in the original sewage, and the denitrification can provide alkalinity for aerobic nitrification. The traditional constructed soil rapid infiltration (CSRI) system, on the other hand, has a poor nitrogen removal effect. Dividing the traditional CSRI system into two sections, one performs denitrification as an anoxic section, while the other performs nitrification as an aerobic section and is placed after the anoxic section. The nitrification liquid of the effluent from the aerobic section is mixed with the original wastewater and enters the anoxic section for denitrification. We expected that this would be improved by combining CSRI with a pre-denitrification step that would make full use of the carbon source in the original sewage. In a small-scale experimental model, the removal efficiencies of nitrogen, in the form of ammonium, nitrate, and total nitrogen (TN), as well as chemical oxygen demand (COD), were determined. The hydraulic load was varied, while the backflow reflux capacity was kept constant, to determine the effect on the pre-denitrification process. An average removal rate of 95.4% for NH4+-N and 96% for COD could be obtained when a hydraulic load of 80 cm3(cm2·d)−1 and a reflux ratio of 75% were applied. Under these conditions, the average removal rate of TN was 77.4%, which is much higher than what can be typically achieved with conventional CSRI systems.

scholarly journals Assessment of the performance of intermittent planted filters in treating urban wastewater under arid climate

2021 ◽  
Author(s):  
Hiba Tlili ◽  
Mahmoud Bali ◽  
Rachid Boukchina
Keyword(s):  
Removal Rate ◽  
Energy Requirement ◽  
Low Cost ◽  
Treatment Plant ◽  
Oxygen Demand ◽  
Pilot Scale ◽  
Ammonium Nitrogen ◽  
Quality Parameters ◽  
Urban Wastewater ◽  
Hydraulic Load

Abstract Intermittent planted filters are extensive biological purification techniques aimed at oxidizing and decontaminating urban wastewater at a low cost and with minimum environmental impacts. The main purpose of this study was to evaluate the performances of intermittent planted filters in treating urban wastewater under arid conditions of southern Tunisia. The experimental study was carried out on a pilot scale plant comprising five constructed gravel-sand basins. Screened urban wastewater effluent was intermittently applied with a daily hydraulic load of 400 L/m2. Several water quality parameters were monitored at the inlet and outlet of this treatment plant. The average removal rate were 94.8%, 92.3%, 99.3%, 89.9% and 93.3% for chemical and biological oxygen demand, total suspended solids, ammonium nitrogen and orthophosphate, respectively. Additionally, results demonstrated that this treatment system is capable to remove 3.67, 3.22 and 2.44 log units of total and faecal coliforms, and faecal streptococci, respectively. Results showed that Phragmites australis allowed the development of biofilm in the sand filter beds, improving their purification efficiency. Furthermore, no bio-sludge production, no mechanical aeration, low energy requirement (0.02 kW/m2) and green aesthetic ambience are the additional particular strengths of the proposed pilot-plant.

Bioaugmentation treatment of PV wafer manufacturing wastewater by microbial culture

2015 ◽  
Vol 72 (5) ◽  
pp. 754-761 ◽  
Author(s):  
Xiaohua Zhu ◽  
Maoxia Chen ◽  
Xin He ◽  
Zili Xiao ◽  
Houzhen Zhou ◽  
...  
Keyword(s):  
Ph Value ◽  
Oxygen Demand ◽  
Operating Conditions ◽  
Small Scale ◽  
Microbial Culture ◽  
Reflux Ratio ◽  
Treatment Unit ◽  
Volume Load ◽  
Treatment Facilities ◽  
Aerobic Treatment Unit

The wastewater of silicon photovoltaic (PV) battery manufacturing contained polyethylene glycol (PEG) and detergents, which possessed the characteristics of high content of organics and low bioavailability, and then resulted in high treatment costs. To address the difficulties of existing treatment facilities in stably meeting discharge standards, eight tons of microbial culture (consisting of Bacillus sp. and Rhodococcus sp.) were added into the aerobic treatment unit. Subsequently, the effectiveness of the microbial culture in small-scale biological wastewater treatment was evaluated, and the operating conditions for engineering applications were optimized. The application study showed that the average chemical oxygen demand (COD) removal efficiency reached 95.0% when the pH value was 7, the gas–water ratio was 28:1, the reflux ratio was 50%, which indicated an increase of 51.2% contrasting with the situation without bioaugmentation. The volume load of the treatment facilities after augmentation increased by 127.9% and could tolerate the COD shock load reached 2,340 mg · L−1. At last, the effluence met the class I standard of the Integrated Wastewater Discharge Standard (GB8978–1996).

Experimental Study on Nitrogen Removal of Domestic Sewage Using Two-Stages Soil Aquifer Treatment System with Pre-Denitrification Process

2014 ◽  
Vol 1065-1069 ◽  
pp. 3049-3054
Author(s):  
Geng Tan ◽  
Hao Dong Zhang ◽  
Yu Ting Wang ◽  
Xiao Wei Duan
Keyword(s):  
Experimental Study ◽  
Nitrogen Removal ◽  
Removal Rate ◽  
High Water ◽  
Domestic Sewage ◽  
Reflux Ratio ◽  
Soil Aquifer Treatment ◽  
Soil Infiltration ◽  
Two Stages ◽  
Denitrification Process

For unstable high water ammonia shortcomings of soil infiltration system for rural sewage, one kind of new soil infiltration systems-two-stages soil aquifer treatment (SAT) system with pre-denitrification process was designed. The results show that when the hydraulic loading is within 0.06-0.08 m3/(m2·d), the effluent CODCr and NH4+-N concentration reach GB18918-2002 level A standard, the removal rate is 91%-94% for CODCr and 95%-98% for NH4+-N. The TN concentration is below 20 mg/L, meeting GB18918-2002 level B standard, and the removal rate is 71%-75%. The TN removal is dramatically affected by reflux ratio.

scholarly journals Riboflavin enhanced denitrification of artificial wastewater under low C/N condition in cold season

BioResources ◽  
2021 ◽  
Vol 16 (1) ◽  
pp. 1949-1957
Author(s):  
Jingya Liu ◽  
Jingang Huang ◽  
Binfang Shi ◽  
Kangyin Guo ◽  
Jianping Li ◽  
...  
Keyword(s):  
Carbon Source ◽  
Nitrogen Removal ◽  
Municipal Wastewater ◽  
Removal Rate ◽  
Cold Season ◽  
Utilization Efficiency ◽  
Electron Mediator ◽  
Arduous Task ◽  
Future Work ◽  
Denitrification Process

Nitrogen removal under low C/N ratio in cold season is an arduous task. In this study, riboflavin was used as an eco-friendly electron mediator to improve the denitrification process in an SBR reactor under conditions of low temperature (10 °C to 15 °C) and limited carbon source (C/N ratio = 4.0). The results indicated that riboflavin created a suitable pH in the system for denitrification. Under water temperature of 10 °C to 15 °C, riboflavin (10 mg/L) stimulated the NO3–N and TN removal rate by 16.5%, and 51%, respectively. Riboflavin promoted the utilization efficiency of limited carbon source, driving the denitrification process with low residual acetate as electron donor. The rising cost of riboflavin supplement (10 mg/L) was 0.025 USD per m3 of wastewater. To satisfy the efficient nitrogen removal from municipal wastewater, the optimum C/N ratio and the selection of solid/immobilized redox mediators should be developed in future work.

Regulating Strategies of Strengthening Nitrogen Removal for Low-Carbon Wastewater in Reversed A2/O Process

2011 ◽  
Vol 243-249 ◽  
pp. 4811-4816 ◽  
Author(s):  
Jie Yun Chen ◽  
Zhi Zhang ◽  
Li Hua Xie ◽  
Ling Kong ◽  
Xiao Jing Yin
Keyword(s):  
Low Temperature ◽  
Carbon Source ◽  
Nitrogen Removal ◽  
Removal Rate ◽  
Experimental Studies ◽  
Reflux Ratio ◽  
Low Carbon ◽  
Efficient Operation ◽  
Anoxic Environment ◽  
Aerobic Zone

According to the ineffective denitrification and the initial controlling technique flaws for low-carbon source in reversed A2/O process, and full scale experimental studies were conducted to strengthen denitrification at normal and low temperature days in 2008~2010, to ensure the best conditions of biological denitrification and promote the stable and efficient operation of the system. The results showed that in normal temperature seasons of 2008, after shortening the HRT of the primary sedimentation tank to 1/3 of design value, improving the MLSS to 4500mg/L, setting the first section of the aerobic zone as the denitrification transition section and improving the reflux ratio, available carbon source was increased by 15%, the effluent NH3-N was 2.5mg / L and the removal rate was 90%, the effluent TN was 17 mg/L and the removal rate was increased to 54% and unit power consumption was reduced by 15% to 0.22Kw•h/m3.At low temperature seasons of 2008~2009,by improving the MLSS to 6000mg/L, extending the sludge age to enrich a large number of nitrification and denitrification bacteria, controlling DO at about 1.2mg / L in the aerobic zone and so on, the effluent NH3-N was 3 mg / L and the removal rate was 88%, the effluent TN was 15.5 mg/L and the removal rate was 62%. In low temperature of 2009 ~2010, besides the same measures as before, adding a blender in the first section of the aerobic zone to provide a better anoxic environment for denitrification and to improve nitrogen removal, the effluent NH3-N was 3 mg / L and the removal rate was 87%, the effluent TN was 13.5 mg/L and the removal rate was 66%.

Pre-Precipitation Facilitates Nitrogen Removal without Tank Expansion

1990 ◽  
Vol 22 (7-8) ◽  
pp. 85-92 ◽  
Author(s):  
Ingemar Karlsson ◽  
Gunnar Smith
Keyword(s):  
Waste Water ◽  
Organic Matter ◽  
Water Treatment ◽  
Carbon Source ◽  
Nitrogen Removal ◽  
Waste Water Treatment ◽  
Chemical Precipitation ◽  
Sewage Water ◽  
Laboratory Studies ◽  
Denitrification Process

Chemically coagulated sewage water gives an effluent low in both suspended matter and organics. To use chemical precipitation as the first step in waste water treatment improves nitrification in the following biological stage. The precipitated sludge contains 75% of the organic matter in the sewage and can by hydrolysis be converted to readily degradable organic matter, which presents a valuable carbon source for the denitrification process. This paper will review experiences from full-scale applications as well as pilot-plant and laboratory studies.

High rate and compact single sludge pre-denitrification process for retrofit

1994 ◽  
Vol 30 (6) ◽  
pp. 31-40 ◽  
Author(s):  
Hiroyshi Emori ◽  
Hiroki Nakamura ◽  
Tatsuo Sumino ◽  
Tadashi Takeshima ◽  
Katsuzo Motegi ◽  
...  
Keyword(s):  
Activated Sludge ◽  
Sewage Treatment ◽  
Treatment Plant ◽  
High Rate ◽  
Activated Sludge Process ◽  
Nitrogen And Phosphorus ◽  
Conventional Activated Sludge ◽  
Treatment Techniques ◽  
Conventional Activated Sludge Process ◽  
Denitrification Process

For the sewage treatment plants near rivers and closed water bodies in urbanized areas in Japan and European countries, there is a growing demand for introduction of advanced treatment processes for nitrogen and phosphorus from the viewpoints of water quality conservation and environmental protection. In order to remove nitrogen by the conventional biological treatment techniques, it is necessary to make a substantial expansion of the facility as compared with the conventional activated sludge process. In such urbanized districts, it is difficult to secure a site and much capital is required to expand the existing treatment plant. To solve these problems, a compact single sludge pre-denitrification process using immobilized nitrifiers was developed. Dosing the pellets, which are suitable for nitrifiers growth and physically durable, into the nitrification tank of single sludge pre-denitrification process made it possible to perform simultaneous removal of BOD and nitrogen in a retention time equal to that in the conventional activated sludge process even at the low water temperature of about 10 °C. The 3,000 m3/d full-scale conventional activated sludge plant was retrofitted and has been successfully operated.

scholarly journals Analysis of Operational Efficiencies and Costs for Extracting Thinned Woods in Small-Scale Forestry, Nasunogahara Area, Tochigi Prefecture, Japan

2020 ◽  
Vol 3 (1) ◽  
pp. 61
Author(s):  
Kazuhiro Aruga
Keyword(s):  
Transportation Costs ◽  
The Other ◽  
Small Scale ◽  
Light Truck ◽  
Operation Costs ◽  
Other Hand ◽  
Light Trucks ◽  
The Cost ◽  
Manual Extraction ◽  
Truck Transportation

In this study, two operational methodologies to extract thinned woods were investigated in the Nasunogahara area, Tochigi Prefecture, Japan. Methodology one included manual extraction and light truck transportation. Methodology two included mini-forwarder forwarding and four-ton truck transportation. Furthermore, a newly introduced chipper was investigated. As a result, costs of manual extractions within 10 m and 20 m were JPY942/m3 and JPY1040/m3, respectively. On the other hand, the forwarding cost of the mini-forwarder was JPY499/m3, which was significantly lower than the cost of manual extractions. Transportation costs with light trucks and four-ton trucks were JPY7224/m3 and JPY1298/m3, respectively, with 28 km transportation distances. Chipping operation costs were JPY1036/m3 and JPY1160/m3 with three and two persons, respectively. Finally, the total costs of methodologies one and two from extraction within 20 m to chipping were estimated as JPY9300/m3 and JPY2833/m3, respectively, with 28 km transportation distances and three-person chipping operations (EUR1 = JPY126, as of 12 August 2020).

scholarly journals Assessment of Voltage Influence in Carbon Dioxide Fixation Process by a Photo-Bioelectrochemical System under Photoheterotrophy

2021 ◽  
Vol 9 (3) ◽  
pp. 474
Author(s):  
Sara Díaz-Rullo Edreira ◽  
Silvia Barba ◽  
Ioanna A. Vasiliadou ◽  
Raúl Molina ◽  
Juan Antonio Melero ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Carbon Source ◽  
Future Development ◽  
Metabolic Pathways ◽  
Co2 Fixation ◽  
Oxygen Demand ◽  
Carbon Uptake ◽  
Bioelectrochemical System ◽  
Electron Sink ◽  
Soluble Carbon

Bioelectrochemical systems are a promising technology capable of reducing CO2 emissions, a renewable carbon source, using electroactive microorganisms for this purpose. Purple Phototrophic Bacteria (PPB) use their versatile metabolism to uptake external electrons from an electrode to fix CO2. In this work, the effect of the voltage (from −0.2 to −0.8 V vs. Ag/AgCl) on the metabolic CO2 fixation of a mixed culture of PPB under photoheterotrophic conditions during the oxidation of a biodegradable carbon source is demonstrated. The minimum voltage to fix CO2 was between −0.2 and −0.4 V. The Calvin–Benson–Bassham (CBB) cycle is the main electron sink at these voltages. However, lower voltages caused the decrease in the current intensity, reaching a minimum at −0.8 V (−4.75 mA). There was also a significant relationship between the soluble carbon uptake in terms of chemical oxygen demand and the electron consumption for the experiments performed at −0.6 and −0.8 V. These results indicate that the CBB cycle is not the only electron sink and some photoheterotrophic metabolic pathways are also being affected under electrochemical conditions. This behavior has not been tested before in photoheterotrophic conditions and paves the way for the future development of photobioelectrochemical systems under heterotrophic conditions.

Integrated Process for Textile Cotton Waste (TCW) Valorization: Waste-to-Energy and Wastewater Decontamination

2016 ◽  
Author(s):  
A. Ribeiro ◽  
C. Vilarinho ◽  
J. Araújo ◽  
J. Carvalho
Keyword(s):  
Raw Materials ◽  
Removal Rate ◽  
Low Cost ◽  
Calorific Value ◽  
Waste To Energy ◽  
Synthetic Wastewater ◽  
Small Scale ◽  
World Population ◽  
Cotton Waste ◽  
Textile Industries

The increasing of world population, industrialization and global consuming, existing market products existed in the along with diversification of raw materials, are responsible for an exponential increase of wastes. This scenario represents loss of resources and ultimately causes air, soils and water pollution. Therefore, proper waste management is currently one of the major challenges faced by modern societies. Textile industries represents, in Portugal, almost 10% of total productive transforming sector and 19% of total employments in the sector composed by almost 7.000 companies. One of the main environmental problems of textile industries is the production of significant quantities of wastes from its different processing steps. According to the Portuguese Institute of Statistics (INE) these industries produce almost 500.000 tons of wastes each year, with the textile cotton waste (TCW) being the most expressive. It was estimated that 4.000 tons of TCW are produced each year in Portugal. In this work an integrated TCW valorisation procedure was evaluated, firstly by its thermal and energetic valorisation with slow pyrolysis followed by the utilization of biochar by-product, in lead and chromium synthetic wastewater decontamination. Pyrolysis experiments were conducted in a small scale rotating pyrolysis reactor with 0.1 m3 of total capacity. Results of pyrolysis experiments showed the formation of 0,241 m3 of biogas for each kilogram of TCW. Results also demonstrated that the biogas is mostly composed by hydrogen (22%), methane (14 %), carbon monoxide (20%) and carbon dioxide (12%), which represents a total high calorific value of 12.3 MJ/Nm3. Regarding biochar, results of elemental analysis demonstrated a high percentage of carbon driving its use as low cost adsorbent. Adsorption experiments were conducted with lead and chromium synthetic wastewaters (25, 50 and 100 mg L−1) in batch vessels with controlled pH. It was evaluated the behaviour of adsorption capacity and removal rate of each metal during 120 minutes of contact time using 5, 10 and 50 g L−1 of adsorbent dosage. Results indicated high affinity of adsorbent with each tested metal with 78% of removal rate in chromium and 95% in lead experiments. This suggests that biochar from TCW pyrolysis may be appropriated to wastewaters treatment, with high contents of heavy metals and it can be an effective alternative to activated carbon.

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