Simultaneous CO2 Treatment and Blue Energy Generation from Wasted Industrial Streams

In the last decade, there has been an increased global need for finding bright solutions to tackle industrial wastes and emissions release. Herein, this work explores the utilization of a compact Reverse Electrodialysis (RED) system that transforms the chemical potential energy of mixing an ammonia based purified industrial wastewater stream (low concentration stream - LC), with an effluent high salinity RO brine stream (High concentration-HC) into viable electrical energy. The LC and HC streams are directed from ammonia production plants and seawater reverse osmosis desalination plants, respectively. The acquired electrical energy from this RED process is simultaneously used to power an Electrochemical (EC) system. The electrochemical system utilizes two critical waste streams produced from ammonia production plants. One being a wastewater stream that is purified in the anode chamber of the cell via the use of active chlorine species, and the other being the huge amount of emitted CO2 that is directed into the cathode chamber and there converted to value added chemicals. The purified wastewater stream coming out of the EC system is used as the aforementioned LC stream in the RED process, hence, forming an integrated RED-EC system that manages industrial waste streams, minimizes liquid discharge & CO2 emissions, and employs a sustainable internal energy production process. In this study, the RED system is first optimized to attain the maximum power density through exploring the influence of concentrate and dilute stream concentrations, compositions and flowrates. In addition, to the number of membrane pairs needed to produce desired voltages. The RED cell gave a maximum power density of 3.25 W.m-2 with 20 membrane pairs and a salinity gradient of 0.98M between a concentrated brine stream and a mixed NaCl/(NH4)2SO4 stream. Furthermore, around 15 cell pairs were needed to provide -1.5 V of energy to drive CO2 conversion to formate.

Averting an outbreak of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) in a university residence hall through wastewater surveillance

A wastewater surveillance program targeting a university residence hall was implemented during the spring semester 2021 as a proactive measure to avoid an outbreak of COVID-19 on campus. Over a period of 7 weeks from early February through late March 2021, wastewater originating from the residence hall was collected as grab samples 3 times per week. During this time, there was no detection of SARS-CoV-2 by RT-qPCR in the residence hall wastewater stream. Aiming to obtain a sample more representative of the residence hall community, a decision was made to use passive samplers beginning in late March onwards. Adopting a Moore Swab approach, SARS-CoV-2 was detected in wastewater samples on just two days after passive samplers were activated. These samples were also positive for the B.1.1.7 (Alpha) Variant of Concern (VOC) by RT-qPCR. The positive result triggered a public health case finding response including a mobile testing unit deployed to the residence hall the following day with testing of nearly 200 students and staff, which identified two laboratory-confirmed cases of B.1.1.7 variant COVID-19. These individuals were re-located to a separate quarantine facility averting an outbreak on campus. Aggregating wastewater and clinical data, the campus wastewater surveillance program has yielded the first estimates of fecal shedding rates of the B.1.1.7 VOC of SARS-CoV-2 in individuals from a non-clinical setting.

Improvement of the technological treatment scheme of iron-containing wastewater from etching operations

The aim of the research is to improve the technological scheme of treatment of iron-containing wastewater from etching operations by creating combined systems, including reagent wastewater treatment, their mutual neutralization, regeneration of etching solutions, deep post-treatment using a magnetic device. The main volume of wastewater is treated in centralized systems with partial return of water to the production process. Spent solutions from etching operations are subject to regeneration with return to the production process and partial dosing into the main wastewater stream from flushing operations. The consumption of commercial HCl is reduced by 50%. The use of hydrogen peroxide can increase the effect of extracting iron from etching solutions by 30% (total purification effect of 70%). Given that deep purification from iron-containing impurities is provided using a magnetic device, the possibilities of practical implementation of reverse osmosis to obtain "pure" water in centralized systems, which can be used for preparation of process solutions and in a mixture with technical water - for flushing operations, increase. In experimental and industrial conditions the expenses of reagents, their concentrations, dosing time are established

Utilization of hydrochar derived from waste paper sludge through hydrothermal liquefaction for the remediation of phenol contaminated industrial wastewater

Hydrothermal liquefaction derived hydrochar produced from industrial paper sludge was used as an adsorbent to remove phenol derivatives from an industrial wastewater stream. Removal efficiency for phenol was determined using synthetic solutions (10–150 ppm) using batch adsorption experiments at a constant solution pH (8), temperature (25 ± 2 °C) and rotary speed (150 rpm). The adsorption of phenol onto hydrochar followed a Freundlich isotherm and could be described with pseudo-second-order kinetic models. Analysis of the adsorption mechanisms showed that particle film mass transport was the rate-determining step in the adsorption process. A COD removal efficiency of 31 ± 1% was achieved for the industrial wastewater stream. All phenol components in the wastewater stream could be removed, but not all organic acids and cyclic ketones. The performance of the paper sludge-based hydrochar compared well with that of activated carbon (44% COD removal). The final phenol concentration in the wastewater stream was below the acceptable phenol concentration for industrial effluents (1 mg/L). The results show that paper sludge can be converted to a valuable marketable commodity that could reduce waste management costs for a paper mill, while also reducing the cost of expensive adsorbents.

Recovery and Reuse of Chromium Ions from Tannery Wastewater by Precipitation Reaction Method

The global concern about the leather industries is increasing as the leather industries grow bigger each year. These industries face a very challenging task with an increase in stringent pollution control regulation enforced by various bodies due to environmental concern and human risks. The chromium salts are the most widely used chemical for the tanning process in leather industries, about 35% of chromium used for the tanning process remain as metal and discharge to wastewater stream. The removal and recovery of this quantity of wasted chromium are necessary for environmental pollution control and economic reason. This paper sheds light on the chromium recovery and reuse system of Chromium salts in tanning wastewater by using NaOH as an effective chemical precipitation method to regenerate chromium solution, adapted chrome recovery plant, and evaluated the system technically and economically.

Conversion of fish processing wastewater into fish feed ingredients through submerged cultivation of Aspergillus oryzae

Fish processing towards production of fillet gives rise to wastewater streams that are ultimately directed to biogas production and/or wastewater treatment. However, these wastewater streams are rich in minerals, fat, and proteins that can be converted to protein-rich feed ingredients through submerged cultivation of edible filamentous fungi. In this study, the origin of wastewater stream, initial pH, cultivation time, and extent of washing during sieving, were found to influence the amount of recovered material from the wastewater streams and its protein content, following cultivation with Aspergillus oryzae. Through cultivation of the filamentous fungus in sludge, 330 kg of material per ton of COD were recovered by sieving, corresponding to 121 kg protein per ton of COD, while through its cultivation in salt brine, 210 kg of material were recovered per ton of COD, corresponding to 128 kg protein per ton of COD. Removal ranges of 12–43%, 39–92%, and 32–66% for COD, total solids, and nitrogen, respectively, were obtained after A. oryzae growth and harvesting in the wastewater streams. Therefore, the present study shows the versatility that the integration of fungal cultivation provides to fish processing industries, and should be complemented by economic, environmental, and feeding studies, in order to reveal the most promising valorization strategy. Graphic abstract

Kinetika Adsorpsi Mikrokapsul Kitosan Taut Silang Kalium Persulfat terhadap Zat Warna Methyl Orange

Dyes, typically available in textile and paper industries, can cause an aesthetical issue in their wastewater stream even in its low concentration Some colors are considered toxic to the environment and even carcinogenic. In that sense, the adsorption using chitosan, might be an alternative method offering better environmental quality by its capability for eliminating the dyes from the waste stream. This research was aimed to study the adsorption kinetics of methyl orange dyes in the presence of chitosan microcapsules, employing the measurement of concentration concerning time over several measured temperatures of 40, 50, and 60 °C. Chitosan microcapsules originated from abundantly available organic materials, have been synthesized by the support of potassium persulfate as a cross-linker through ionic gelation and solvent evaporation method. The microcapsules were subjected to Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM) characterizations, while UV-Vis was utilized for observing dye concentration changes. The results showed that chitosan microcapsules had been successfully prepared with a deacetylation degree of 53.92 % and a grain diameter of 1246 μm. The adsorption adapted the chemisorption mechanism with endothermic behavior. Besides, its kinetics seemed to follow the Lagergren pseudo-second-order equation with the value of the kinetic constant suitable for the tested temperature, following the Arrhenius equation. A B S T R A KZat pewarna yang banyak ditemukan di industri tekstil dan kertas, cenderung menyebabkan masalah estetika dalam aliran air limbah meskipun dalam jumlah rendah. Beberapa zat pewarna bersifat racun bagi lingkungan dan bahkan ada yang tergolong zat karsinogen. Adsorpsi, terutama dengan memanfaatkan kitosan, dapat digunakan sebagai metode alternatif yang memberikan kualitas lingkungan yang lebih baik dalam menghilangkan zat warna dari aliran limbah. Penelitian ini bertujuan untuk mempelajari kinetika adsorpsi pewarna metil oranye menggunakan kitosan dalam bentuk mikrokapsul, dengan mengamati perubahan konsentrasi sebagai fungsi waktu pada beberapa suhu teruji yaitu 40, 50, dan 60 °C. Mikrokapsul kitosan berasal dari bahan organik yang tersedia berlimpah dan disintesis dengan bantuan kalium persulfat sebagai penaut silang dengan menggunakan metode gelasi ionik dan metode penguapan pelarut. Karakteristik mikrokapsul dianalisis menggunakan spektroskopi Fourier transform infrared (FT-IR) dan scanning electron microscopy (SEM), sedangkan UV-Vis digunakan untuk mengamati perubahan konsentrasi zat warna. Hasil penelitian menunjukkan, mikrokapsul kitosan yang berhasil disintesis mempunyai derajat deasetilasi 53,92% dan diameter butir sekitar 1246 μm. Adsorpsi mengikuti mekanisme kemisorpsi dengan perilaku endotermik. Persamaan kinetik mengikuti persamaan Lagergren orde dua-semu dengan nilai konstanta kinetik untuk suhu yang diuji mengikuti persamaan Arrhenius.