Evaluation of the treatment performance and reuse potential in agriculture of organized industrial zone (OIZ) wastewater through an innovative vermifiltration approach

© 2022 Elsevier LtdVermifiltration (VF) is a natural and sustainable biofilter that has many advantages, including being energy-free, cost-effective, and allowing ease of application and maintenance. In this study, the effectiveness of a lab-scale VF system was assessed by the removal efficiency of total suspended solids, electrical conductivity, chemical oxygen demand, total nitrogen, total phosphorus, fecal coliform, and heavy metals in organized industrial zones (OIZ) and domestic wastewater (DW) for the first time. Additionally, the reuse suitability of the treated wastewater was determined by comparing different countries' and global irrigational criteria. The lab systems were built with four layers: one worm-bed and three varying filtering materials, and operated at an optimum hydraulic loading rate of 1.8–2 m3/m2/day for 45 days with Eisenia fetida as the earthworm species. The results demonstrated that removal efficiencies of total suspended solids and chemical oxygen demand were found to be 95% and 80% in OIZ wastewater and 90% and 88% in DW, respectively. Total nitrogen and total phosphorus were removed at rates of 69% and 67% in OIZ wastewater, respectively, and 84% and 74% in DW. Besides, the VF system has shown satisfactory removal performance for heavy metals ranging from 51% to 77% in OIZ wastewater that has met Turkish national wastewater discharge limits. Although the final characterization of treated wastewater was suitable, heavy metal and fecal coliform levels have not met many countries' irrigation water quality criteria. To meet global irrigation standards and to enhance the VF performance, further experimental studies should be carried out, including parameters such as bed material type in the reactor, worm type, and different operating conditions

Effects of spray drying temperature and additives on the stability of serine alkaline protease powders

In this study, after production by recombinant Bacillus subtilis (BGSC-1A751), carrying pHV1431:: subc gene in the complex medium and separation of solids from the fermentation broth, serine alkaline protease (SAP) was dried in order to investigate the stabilization during spray drying and subsequent storage. The effect of air inlet temperature of the spray dryer between T = 70 and 130 degrees C and the effect of protective additives, glucose and maltodextrin, at 0-2% (w/v) on SAP activity during spray drying and storage stability of obtained SAP powders at 4 degrees C for a long period (6 months) were evaluated. Increasing drying air inlet temperature generally resulted in an increase in activity loss; moreover, higher absorbance peaks observed at wave number 1061 cm(-1) of the IR spectrums when drying temperature is increased indicates the structural change in the SAP molecule. In most cases presence of additives provided higher activities both after drying and during storage period compared to no additive case. Drying the enzyme with 1% (w/v) glucose at T =110 degrees C resulted in the highest enzyme activity after drying and storage processes