Cycling of phosphorus from wastewater to fertilizer using wood ash after energy production.

Quercus wood was used for thermal energy production, and wood bottom ash (WDBA) was used as a medium for water purification and soil fertilizer in accordance with the recently proposed food-water-energy nexus concept. The wood contained a gross calorific value of 14.83 MJ kg-1, and the gas generated during thermal energy production has the advantage of not requiring a desulfurization unit due to its low sulfur content. Wood-fired boilers emit less CO2 and SOX than coal boilers. The WDBA had a Ca content of 66.0%, and Ca existed in the forms of CaCO3 and Ca(OH)2. WDBA absorbed P by reacting with Ca in the form of Ca5(PO4)3OH. Kinetic and isotherm models revealed that the results of the experimental work were in good agreement with the pseudo-second-order and Langmuir models, respectively. The maximum P adsorption capacity of WDBA was 76.8 mg g-1, and 6.67 g L-1 of WDBA dose could completely remove P in water. The toxic units of WDBA tested using Daphnia magna were 6.1, and P adsorbed WDBA (P-WDBA) showed no toxicity. P-WDBA was used as an alternative P fertilizer for rice growth. P-WDBA application resulted in significantly greater rice growth in terms of all agronomic values compared to N and K treatments without P. This study proposed the utilization of WDBA, obtained from thermal energy production, to remove P from wastewater and replenish P in the soil for rice growth.

Recycling of bottom ash derived from combustion of cattle manure and its adsorption behaviors for Cd(II), Cu(II), Pb(II), and Ni(II).

Bottom ash generated by the combustion of cattle manure (BA-CCM) was investigated as an adsorbent for the removal of heavy metals such as Cd(II), Cu(II), Pb(II), and Ni(II) from aqueous solutions. When cattle manure was used as fuel, the thermal efficiency of the boiler was 88.7%, and the CO and CO2 concentrations in the exhaust gas were 2.3 ppm and 12.1%, respectively. The percentage of remaining solids was 31 wt.% after combustion at 900 °C. X-ray fluorescence analyses showed that the elemental composition of the BA-CCM was mainly CaO (43.3%), SiO2 (15.8%), CO2 (13.0%), and P2O5 (10.3%). The kinetic adsorption of Cd(II), Cu(II), Pb(II), and Ni(II) by BA-CCM reached equilibrium after 12 h, and the pseudo-second-order model fitted the experimental data well. The maximum amount of Cd(II), Cu(II), Pb(II), and Ni(II) adsorbed by the bottom ash was 5.4, 72.6, 88.2, and 24.6 mg/g, respectively. The equilibrium adsorption of metals onto BA-CCM was well-described by the Freundlich model. Thermodynamic analysis showed that the adsorption onto the bottom ash was endothermic and that the Gibbs free energy decreased as the temperature increased. The presence of cations such as Na+, Ca2+, and Al3+ was found to reduce the amount of metals adsorbed onto the BA-CCM, and Cd(II) adsorption was found to be more dependent on ionic strength than adsorption of Cu(II), Pb(II), and Ni(II). This study demonstrates the feasibility of producing heat energy by burning cattle manure and removing heavy metals from aqueous solutions using the generated bottom ash as an adsorbent.

Performance Analysis of Gravity-Driven Oil-Water Separation Using Membranes with Special Wettability.

A membrane with selective wettability to either oil or water has been utilized for highly efficient, environmentally friendly membrane-based oil-water separation. However, a predictive model, which can be used to evaluate the overall separation performance of the membrane, still needs further development. Herein, we investigate three separation performance parameters, that is, separation efficiency, liquid intrusion pressure, and mass flux in particular, as a function of pore geometry and liquid properties using metallic meshes whose surface wettability is modified by scalable spray coating. We show that the prepared membrane exhibits a separation efficiency over 98% below the intrusion pressure, while the intrusion pressure increases with the decrease of pore size of the membrane. Particularly, we develop a semi-empirical model for the mass flux through the membrane. As application examples of our performance analysis, we successfully predict the separation time for one-way and two-way gravity-driven separation of the oil-water mixture, the decrease of the mass flux due to membrane fouling, and the maximum allowable separation capacity of the given membrane. This work can help to design optimal membrane-based oil-water separation systems for actual industrial applications by providing a selection guideline for separation membranes.

Optimal extent of prophylactic central neck dissection for papillary thyroid carcinoma: Comparison of unilateral versus bilateral central neck dissection.

OBJECTIVE: The aim of the study was to determine the optimal extent of prophylactic central neck dissection (pCND) in papillary thyroid carcinoma (PTC). MATERIALS AND METHODS: We studied 384 patients with clinically node-negative unilateral PTC who had undergone total thyroidectomy with pCND. Of these, 169 patients underwent unilateral pCND, and 215, bilateral pCND. RESULTS: Age, sex, and TNM stage did not differ between the two groups. The rates of occult central lymph node metastasis were 34.3% and 37.2% in the unilateral and bilateral pCND groups, respectively (p = 0.558). Metastasis to the contralateral paratracheal lymph node occurred in 4.2% of the bilateral pCND group. Major complication rates did not differ between the two groups, except for transient hypoparathyroidism, which was higher in the bilateral group (43.7% vs. 33.7%, p = 0.047). Stimulated thyroglobulin and RAI ablation uptake rates were similar in the two groups, as were recurrence and disease-free survival. CONCLUSION: Contralateral paratracheal node dissection may be not indicated for prophylactic central neck dissection in clinically node-negative unilateral PTC because the rate of contralateral paratracheal node metastasis is low and transient hypoparathyroidism is higher following bilateral dissection.

Bilateral cochlear implantation in a patient with bilateral temporal bone fractures.

With the emphasis on bilateral hearing nowadays, bilateral cochlear implantation has been tried out for bilateral aural rehabilitation. Bilateral sensorineural hearing loss caused by head trauma can get help from cochlear implantation. We present the case of a 44-year-old man with bilateral otic capsule violating temporal bone fractures due to head trauma. The patient demonstrated much improved audiometric and psychoacoustic performance after bilateral cochlear implantation. We believe bilateral cochlear implantation in such patient can be a very effective tool for rehabilitation.