Grey water footprint for evaluating Zefta wastewater treatment plant: a case study.

The numbers of wastewater treatment plants (WWTP) in Egypt are increasing, yet the general level of pollution associated with wastewater discharge after treatment has not been evaluated. Grey water footprint (GWF) was used to assess the effluent discharges from Zefta WWTP. GWF, before and after treatment, was calculated and followed up to determine its impact on the receiving freshwater body. 150 samples were collected and analysed for BOD5 to determine the optimum operating conditions. Averages values were DO = 2.2, SV30 = 500, SVI = 167, SA = 9.3 d, MLVSS = 2392 mg/L, f/m = 0.16, MLSS in RAS = 7922 mg/L, WAS = 140 m3/d and the HRT = 12 h. The removal efficiency of COD and TSS in the primary settling tank reached 39% and 69%, respectively. Average calculations of removal efficiency percentile reached 90-93%. Average freshwater quantities required to reduce pollutants in the receiving body stream were seasonally determined for Zefta WWTP as 5.3 × 107 m3/year. The average influent BOD5 was 376 mg/L, it was reduced to 47 mg/L in the effluent, wherever the Cmin is 6 mg/L and Cnat is 10 mg/L. Statistical analysis has shown a significant direct relation between ΔWFG,mef and WFG,ref reached 0.952 and a significant inverse relation with Cef -0.982. WFG,T has shown a significant direct relation with Cr 0.974. WFG,T- ref has shown a significant direct relation with Cr as 0.971 and WFG,T as 0.803. It can be concluded that ΔWF is effective in evaluating the efficiency of wastewater treatment and its effect on the quality of receiving water bodies.

Anatase-cellulose acetate for reinforced desalination membrane with antibacterial properties.

This study aimed to prepare antifouling and highly mechanical strengthening membranes for brackish and underground water desalination. It was designed from cellulose acetate (CA) loaded anatase. Anatase was prepared from tetra-iso-propylorthotitanate and carboxymethyl cellulose. Different concentrations of anatase (0.2, 0.3, 0.5, 0.6, 0.7, and 0.8)% were loaded onto CA during the inversion phase preparation of the membranes. The prepared membranes were characterized using Fourier Transform Infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy (SEM & EDX), mechanical properties, swelling ratio, porosity determination, and ion release. The analysis confirmed the formation of anatase on the surface and inside the macro-voids of the membrane. Furthermore, anatase loading improved the CA membrane's mechanical properties and decreased its swelling and porosity rate. Also, CA-loaded anatase membranes displayed a significant antibacterial potential against Gram-positive and Gram-negative bacteria. The results showed that the salt rejection of the CA/anatase films as-prepared varies considerably with the addition of nanomaterial, rising from 46%:92% with the prepared membranes under the 10-bar operation condition and 5 g/L NaCl input concentration. It can be concluded that the prepared CA-loaded anatase membranes have high mechanical properties that are safe, economical, available, and can stop membrane biofouling.