Hala Salah Doma

Waste stabilization ponds (WSPs) as natural wastewater treatment plants are commonly utilized for wastewater treatment due to their simple design, low cost, and low-skilled operator requirements. Large-scale studies assessing the performance of WSPs using multivariate statistical models are scarce. Therefore, this study was conducted to assess the performance of 16 full-scale WSPs regarding physicochemical parameters, algae, bacterial indicators, and pathogens (e.g., Cryptosporidium, Entamoeba histolytica) by using multivariate statistical models. The principal component analysis revealed that the chemical pollutants were removed significantly (p < 0.001) through the treatment stages of 16 WSPs, indicating that the treatment stages made a substantial change in the environmental parameters. The non-multidimensional scale analysis revealed that the treatment stages restructured the bacterial indicators significantly (p < 0.001) in the WSPs, implying that the bacterial indicators were removed with the progress of the treatment processes. The algal community exhibited a distinct pattern between the geographical location (i.e., upper WSPs versus lower WSPs) and different treatment stages (p < 0.001). Four out of the sixteen WSPs did not comply with the Egyptian ministerial decree 48/1982 for discharge in agriculture drainage; three of these stations are in lower Egypt (M.K., Al-Adlia, and Ezbet El-Borg), and one is in upper Egypt (Armant). The continuous monitoring of WSPs for compliance with regulatory guidelines with the aid of multivariate statistical models should be routinely performed.

This study evaluates the efficiency of a sustainable technology represented in an integrated pilot-scale system, which includes a facultative pond (FP), a high-rate algal pond (HRAP), and a rock filter (RF) for wastewater treatment to produce water that complies with the Egyptian standards for treated wastewater reuse. Still, limited data are available on pathogen removal through HRAP systems. Thus, in this study, the performance of the integrated system was investigated for the removal of Escherichia coli (E. coli), coliform bacteria, eukaryotic pathogens (Cryptosporidium spp., Giardia intestinalis, and helminth ova), somatic coliphages (SOMCPH), and human adenovirus (HAdV). Furthermore, physicochemical parameters were determined in order to evaluate the performance of the integrated system. The principal component analysis and non-metric multidimensional scaling analysis showed a strong significant effect of the integrated system on changing the physicochemical and microbial parameters from inlet to outlet. The mean log₁₀ removal values for total coliform, fecal coliform, and E. coli were 5.67, 5.62, and 5.69, respectively, while 0.88 log₁₀ and 1.65 log₁₀ reductions were observed for HAdV and SOMCPH, respectively. The mean removal of Cryptosporidium spp. and Giardia intestinalis was 0.52 and 2.42 log₁₀, respectively. The integrated system achieved 100% removal of helminth ova. The results demonstrated that the system was able to improve the chemical and microbial characteristics of the outlet to acceptable levels for non-food crops irrigation. Such findings together with low operation and construction costs of HRAPs should facilitate wider implementation of these nature-based systems in remote and rural communities. Overall, this study provides a novel insight into the performance of such systems to eliminate multiple microbial pathogens from wastewater.

Slaughterhouse wastewater (SWW) is a typical source of pollution and creates serious environmental concerns. Therefore, SWW needs a cost effective and efficient treatment technology for safe discharge and consequently for public health protection. The aim of the study was to evaluate the treatment of SWW by two steps, first one was primary treatment by screening and settling followed by biological treatment using of Horizontal Flow Biofilm Reactor (HFBR) as a second step. A significant review of raw SWW characteristics was presented, COD, BOD and TSS concentrations values were very high its maximum values reached 9855, 5037 and 3440 mg/l, respectively. The primary treatment removed 34% COD and 75% TSS. The performance of HFBR system has been investigated in continuous mode. The system was operated at two different organic loading rates to find out the optimum operating conditions, which produce treated effluent characterization compatible with the Egyptian legislation for discharge on sewerage network. The organic loads (OLR) applied to the HFBR system were 0.53 and 1.3 kg COD/m2/d. During the steady-state of optimum operating conditions, the system achieved significant carbon removal of 85% and 95% for COD and TSS respectively. Nitrogen removal percentage reached 50% ammonia-nitrogen and 56% for total nitrogen. From the results obtained HFBR could be considered as a reliable treatment technology for SWW.