scholarly journals Hydrolytic Acidification-Two Stage EGSB-A/O Combined Process for Pesticide Wastewater Treatment

2021 ◽  
pp. 168-181
Author(s):  
Y. Sun
Keyword(s):  
Salt Content ◽  
Impact Resistance ◽  
Granular Sludge ◽  
High Salt ◽  
Fenton Oxidation ◽  
Stable Operation ◽  
Strong Impact ◽  
Two Stage ◽  
Combined Process ◽  
Hydrolytic Acidification

The wastewater produced by a chemical enterprise in Ningxia has the characteristics of high COD, high salt content, and high ammoniacal nitrogen. The biodegradability of the wastewater is poor due to presence of higher concentration of pollutant. The scale of first stage of treatment was 400m3/d. The wastewater of different characteristic was collected and treated separately. The combined process of "micro electrolysis + Fenton oxidation + coagulation precipitation + evaporation crystallization" was used to pretreat the wastewater containing high salt and high COD. The main process was "hydrolytic acidification + two-stage Expanded Granular Sludge Bed (EGSB) + two-stage advance Fenton oxidation (A/O)". The final concentrations of effluent COD, NH3-N and TDS are 376 mg/L, 34.74 mg/L, and 442 mg/L, and the removal rates are 99.9%, 81.3%, and 99.9%, respectively. The environmental, engineering and economical (3E) practices showed that the combined process has stable operation, strong impact resistance, and high reduction of COD in the effluent.

Desalination of high salt content mixture by two-stage electrodialysis as the first step of separating valuable substances from grass silage

Desalination ◽  
2004 ◽  
Vol 162 ◽  
pp. 343-353 ◽  
Author(s):  
Vu Hong Thang ◽  
Werner Koschuh ◽  
Klaus D Kulbe ◽  
Stefan Kromus ◽  
Christian Krotscheck ◽  
...  
Keyword(s):  
Salt Content ◽  
High Salt ◽  
Two Stage ◽  
Grass Silage ◽  
High Salt Content

Study on Pretreatment of Azithromycin Wastewater Technology

2014 ◽  
Vol 1073-1076 ◽  
pp. 821-824 ◽  
Author(s):  
Li Dong Wang ◽  
Ya Rong Dong
Keyword(s):  
Salt Content ◽  
High Salt ◽  
Fenton Oxidation ◽  
Total Removal ◽  
Ammonia Stripping ◽  
High Salt Content ◽  
High Ammonia ◽  
Content Characteristics

Azithromycin wastewater has high ammonia, high COD and high salt content characteristics. By ammonia stripping-Fenton oxidation pretreatment of azithromycin wastewater, the effect is obvious. The optimum technological conditions are determined by experiments, the effluent COD can be reduced to 5000mg/L or less, the total removal of up to 85.6%. After pretreatment of wastewater, the BOD5/COD value was increased from 0.12 to 0.38, and the biodegradability of the wastewater was improved.

The anaerobic treatment of a ligno-cellulosic substrate offering little natural pH buffering capacity

1998 ◽  
Vol 38 (4-5) ◽  
pp. 29-35 ◽  
Author(s):  
C. J. Banks ◽  
P. N. Humphreys
Keyword(s):  
Ph Control ◽  
Anaerobic Treatment ◽  
Buffering Capacity ◽  
Single Stage ◽  
Stable Operation ◽  
Reactor Performance ◽  
Two Stage ◽  
Ph Buffering ◽  
Stage System ◽  
The Stability

The stability and operational performance of single stage digestion with and without liquor recycle and two stage digestion were assessed using a mixture of paper and wood as the digestion substrate. Attempts to maintain stable digestion in both single stage reactors were unsuccessful due to the inherently low natural buffering capacity exhibited; this resulted in a rapid souring of the reactor due to unbuffered volatile fatty acid (VFA) accumulation. The use of lime to control pH was unsatisfactory due to interference with the carbonate/bicarbonate equilibrium resulting in wide oscillations in the control parameter. The two stage system overcame the pH stability problems allowing stable operation for a period of 200 days without any requirement for pH control; this was attributed to the rapid flushing of VFA from the first stage reactor into the second stage, where efficient conversion to methane was established. Reactor performance was judged to be satisfactory with the breakdown of 53% of influent volatile solids. It was concluded that the reactor configuration of the two stage system offers the potential for the treatment of cellulosic wastes with a sub-optimal carbon to nitrogen ratio for conventional digestion.

Performance of an anaerobic baffled reactor (ABR) as a hydrolysis-acidogenesis unit in treating landfill leachate mixed with municipal sewage

2000 ◽  
Vol 42 (12) ◽  
pp. 115-121 ◽  
Author(s):  
B. Wang ◽  
Y. Shen
Keyword(s):  
Landfill Leachate ◽  
Loading Rate ◽  
Granular Sludge ◽  
Operational Performance ◽  
Municipal Sewage ◽  
Organic Loading Rate ◽  
Stable Operation ◽  
Organic Loading ◽  
Anaerobic Baffled Reactor ◽  
Biological Treatability

A study on the performance of an Anaerobic Baffled Reactor(ABR) as a hydrolysis-acidogenesis unit in treating the mixed wastewater of landfill leachate and municipal sewage in different volumetric ratios was carried out. The results showed that ABR substantially improved the biological treatability of the mixed wastewater by increasing its BOD5/COD ratio to 0.4–0.6 from the initial values of 0.15–0.3. The formation of bar-shaped granular sludge of 0.5–5 mm both in diameter and length with an SVI of 7.5–14.2 ml/g was observed in all compartments of the ABR when the organic loading rate reached 4.71 kgCOD/m3 · d. The effects of the ratios of NH4+-N/COD and COD/TP in mixed wastewater on the operational performance were also studied, from which it was found that a reasonable NH4+-N/COD ratio should be lower than 0.02, and the phosphorus supplement was needed when the volumetric ratio was higher than 4:6 for stable operation of ABR.

scholarly journals Adaptive-MPPT-Based Control of Improved Photovoltaic Virtual Synchronous Generators

Energies ◽  
2018 ◽  
Vol 11 (7) ◽  
pp. 1834 ◽  
Author(s):  
Xiangwu Yan ◽  
Jiajia Li ◽  
Ling Wang ◽  
Shuaishuai Zhao ◽  
Tie Li ◽  
...  
Keyword(s):  
Energy Storage ◽  
Control Method ◽  
Synchronous Generator ◽  
Storage Device ◽  
Stable Operation ◽  
Energy Storage Devices ◽  
Two Stage ◽  
Additional Energy ◽  
Control Approach ◽  
Pv Grid

The lack of inertia and damping mechanism of photovoltaic (PV) grid-connected systems controlled by maximum power point tracking (MPPT) poses a challenge for the safety and stability of the grid. Virtual synchronous generator (VSG) technology has attracted wide attention, since it can make PV grid-connected inverter present the external characteristics of a synchronous generator (SG). Nevertheless, traditional PV-VSG is generally equipped with an energy storage device, which leads to many problems, such as increased costs, space occupation, and post-maintenance. Thus, this paper proposes a two-stage improved PV-VSG control method based on an adaptive-MPPT algorithm. When PV power is adequate, the adaptive-MPPT allows the PV to change the operating point within a stable operation area to actualize system supply-demand, matching in accordance to the load or dispatching power demand; when PV power is insufficient, PV achieves traditional MPPT control to reduce power shortage; simultaneously, improved VSG control prevents the DC bus voltage from falling continuously to ensure its stability. The proposed control approach enables the two-stage PV-VSG to supply power to loads or connect to the grid without adding additional energy storage devices, the effectiveness of which in off-grid and grid-connected modes is demonstrated by typical simulation conditions.

scholarly journals Treatment of oilfield wastewater by combined process of micro-electrolysis, Fenton oxidation and coagulation

2017 ◽  
Vol 76 (12) ◽  
pp. 3278-3288 ◽  
Author(s):  
Zhenchao Zhang
Keyword(s):  
Reaction Time ◽  
Removal Efficiency ◽  
Treatment Process ◽  
Cod Removal ◽  
Fenton Oxidation ◽  
Oily Wastewater ◽  
Optimum Conditions ◽  
Combined Process ◽  
Cod Removal Efficiency ◽  
Optimized Conditions

Abstract In this study, a combined process was developed that included micro-electrolysis, Fenton oxidation and coagulation to treat oilfield fracturing wastewater. Micro-electrolysis and Fenton oxidation were applied to reduce chemical oxygen demand (COD) organic load and to enhance organic components gradability, respectively. Orthogonal experiment were employed to investigate the influence factors of micro-electrolysis and Fenton oxidation on COD removal efficiency. For micro-electrolysis, the optimum conditions were: pH, 3; iron-carbon dosage, 50 mg/L; mass ratio of iron-carbon, 2:3; reaction time, 60 min. For Fenton oxidation, a total reaction time of 90 min, a H2O2 dosage of 12 mg/L, with a H2O2/Fe2+ mole ratio of 30, pH of 3 were selected to achieve optimum oxidation. The optimum conditions in coagulation process: pH, cationic polyacrylamide dosage, mixing speed and time is 4.3, 2 mg/L, 150 rpm and 30 s, respectively. In the continuous treatment process under optimized conditions, the COD of oily wastewater fell 56.95%, 46.23%, 30.67%, respectively, from last stage and the total COD removal efficiency reached 83.94% (from 4,314 to 693 mg/L). In the overall treatment process under optimized conditions, the COD of oily wastewater was reduced from 4,314 to 637 mg/L, and the COD removal efficiency reached 85.23%. The contribution of each stage is 68.45% (micro-electrolysis), 24.07% (Fenton oxidation), 7.48% (coagulation), respectively. Micro-electrolysis is the uppermost influencing process on COD removal. Compared with the COD removal efficiency of three processes on raw wastewater under optimized conditions: the COD removal efficiency of single micro-electrolysis, single Fenton oxidation, single coagulation is 58.34%, 44.88% and 39.72%, respectively. Experiments proved the effect of combined process is marvelous and the overall water quality of the final effluent could meet the class III national wastewater discharge standard of petrochemical industry of China (GB8978-1996).

Sign in / Sign up

Export Citation Format

Share Document