Phosphorus Recovery From Waste Activated Sludge by Sponge Iron Seeded Crystallization of Vivianite and Process Optimization With Response Surface Methodology

2021 ◽  
Author(s):  
Guoding Wu ◽  
Wei Zeng ◽  
Shuaishuai Li ◽  
Ziyue Jia ◽  
Yongzhen Peng
Keyword(s):  
Response Surface Methodology ◽  
Activated Sludge ◽  
Response Surface ◽  
Economic Value ◽  
Recovery Process ◽  
Sponge Iron ◽  
Seed Crystal ◽  
Phosphorus Recovery ◽  
Molar Ratio ◽  
Waste Activated Sludge

Abstract As a novel phosphorus recovery product, vivianite (Fe3(PO4)2·8H2O) has attracted much attention due to its enormous recycling potential and foreseeable economic value. Taking sponge iron as seed material, the effect of different reaction conditions on the recovery of phosphorus in waste activated sludge by vivianite crystallization was studied. Through single factor test, the optimal conditions for vivianite formation were in the pH range of 5.5–6.0 with Fe/P molar ratio of 1.5. Scanning electron microscopy (SEM), powder X-ray diffraction (XRD) and energy dispersive spectroscopy (EDS) were used to analyze the components of the crystals. The results showed that the vivianite produced with sponge iron as the seed crystal were larger and thicker (300-700 μm) than other seed (200-300 μm) and without seed (50-100 μm). Moreover, vivianite, which was synthesized with sponge iron as seed, was obviously magnetic and could be separated from sludge by rubidium magnet. The Box-Behnken design of the response surface methodology was used to optimize the phosphorus-recovery process with sponge iron (maximum phosphorus recovery rate was 83.17%), and the interaction effect of parameters was also examined. PH had a significant effect on the formation of vivianite. In summary, this research verifies the feasibility of using sponge iron as seed crystal to recover phosphorus in the form of vivianite from waste activated sludge, which is conducive to the subsequent separation and utilization of vivianite.

scholarly journals Application of electrochemical peroxidation (ECP) process for waste-activated sludge stabilization and system optimization using response surface methodology (RSM)

2018 ◽  
Vol 77 (6) ◽  
pp. 1765-1776 ◽  
Author(s):  
Gagik Badalians Gholikandi ◽  
Khashayar Kazemirad
Keyword(s):  
Response Surface Methodology ◽  
Activated Sludge ◽  
Response Surface ◽  
Removal Efficiency ◽  
Ph Value ◽  
System Optimization ◽  
Waste Activated Sludge ◽  
Operational Conditions ◽  
Sludge Stabilization ◽  
Rsm Optimization

Abstract In this study, the performance of the electrochemical peroxidation (ECP) process for removing the volatile suspended solids (VSS) content of waste-activated sludge was evaluated. The Fe2+ ions required by the process were obtained directly from iron electrodes in the system. The performance of the ECP process was investigated in various operational conditions employing a laboratory-scale pilot setup and optimized by response surface methodology (RSM). According to the results, the ECP process showed its best performance when the pH value, current density, H2O2 concentration and the retention time were 3, 3.2 mA/cm2, 1,535 mg/L and 240 min, respectively. In these conditions, the introduced Fe2+ concentration was approximately 500 (mg/L) and the VSS removal efficiency about 74%. Moreover, the results of the microbial characteristics of the raw and the stabilized sludge demonstrated that the ECP process is able to remove close to 99.9% of the coliforms in the raw sludge during the stabilization process. The energy consumption evaluation showed that the required energy of the ECP reactor (about 1.8–2.5 kWh (kg VSS removed)−1) is considerably lower than for aerobic digestion, the conventional waste-activated sludge stabilization method (about 2–3 kWh (kg VSS removed)−1). The RSM optimization process showed that the best operational conditions of the ECP process comply with the experimental results, and the actual and the predicted results are in good conformity with each other. This feature makes it possible to predict the introduced Fe2+ concentrations into the system and the VSS removal efficiency of the process precisely.

Optimization of biodiesel synthesis under simultaneous ultrasound-microwave irradiation using response surface methodology (RSM)

2015 ◽  
Vol 4 (4) ◽  
Author(s):  
Seyed Mohammad Safieddin Ardebili ◽  
Teymor Tavakoli Hashjin ◽  
Barat Ghobadian ◽  
Gholamhasan Najafi ◽  
Stefano Mantegna ◽  
...  
Keyword(s):  
Response Surface Methodology ◽  
Microwave Irradiation ◽  
Response Surface ◽  
Palm Oil ◽  
Catalyst Concentration ◽  
Irradiation Time ◽  
Operating Conditions ◽  
Molar Ratio ◽  
Reaction Conditions ◽  
Biodiesel Synthesis

AbstractThis work investigates the effect of simultaneous ultrasound-microwave irradiation on palm oil transesterification and uncovers optimal operating conditions. Response surface methodology (RSM) has been used to analyze the influence of reaction conditions, including methanol/palm oil molar ratio, catalyst concentration, reaction temperature and irradiation time on biodiesel yield. RSM analyses indicate 136 s and 129 s as the optimal sonication and microwave irradiation times, respectively. Optimized parameters for full conversion (97.53%) are 1.09% catalyst concentration and a 7:3.1 methanol/oil molar ratio at 58.4°C. Simultaneous ultrasound-microwave irradiation dramatically accelerates the palm oil transesterification reaction. Pure biodiesel was obtained after only 2.2 min while the conventional method requires about 1 h.

Comparison of different modeling methods toward predictive capability evaluation of the bonding strength of wood laminated products

2021 ◽  
pp. 095440892110530
Author(s):  
Morteza Nazerian ◽  
Seyed Ali Razavi ◽  
Ali Partovinia ◽  
Elham Vatankhah ◽  
Zahra Razmpour
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Response Surface Methodology ◽  
Response Surface ◽  
Bonding Strength ◽  
Fuzzy Inference ◽  
Molar Ratio ◽  
Inference System ◽  
Neuro Fuzzy ◽  
Artificial Neural

The main aim of this study is usability evaluation of different approaches, including response surface methodoloy, adaptive neuro-fuzzy inference system, and artificial neural network models to predict and evaluate the bonding strength of glued laminated timber (glulam) manufactured using walnut wood layers and a natural adhesive (oxidized starch adhesive), with respect to this fact that using the modified starch can decrease the formaldehyde emission. In this survey, four variables taken as the input data include the molar ratio of formaldehyde to urea (1.12–1.52), nanocellulose content (0%–4%, based on the dry weight of the adhesive), the mass ratio of the oxidized starch adhesive to the urea formaldehyde resin (30:70–70:30), and the press time (4–8 min). In order to find the best predictive performance of each selected evaluation approach, different membership functions were used. The optimal results were obtained when the molar ratio, nanocellulose content, mass ratio of the oxidised starch, and press time were set at 1.22, 3%, 70:30, and 7 min, respectively. Based on the performance criteria including root mean square error (RMSE) and mean absolute percentage error (MAPE) obtained from the modeling of response surface methodology, adaptive neuro-fuzzy inference network, and artificial neural network, it became evident that response surface methodology could offer a better prediction of the response with the lowest level of errors. Beside, artificial neural network and adaptive neuro-fuzzy inference system support the response surface methodology approach to evaluate bonding strength response with high precision as well as to determine the optimal point in fabrication of laminated products.

Sign in / Sign up

Export Citation Format

Share Document