Evaluating the periphyton as a bioreactor for removal of nutrients in a shallow hypereutrophic reservoir

Aim We evaluated the periphyton on artificial substrate in the treated sewage effluent, effluent patch, inside and after the macrophyte stand in a shallow hypereutrophic reservoir. Specifically, we investigated the relationship between N and P contents and algal biomass in the periphyton with N and P availability, focusing on nutrient retention. Methods Periphyton sampling was performed at the effluent inlet, effluent path, inside, and two sites after macrophyte stand. Periphyton sampling was performed after 30 days of colonization. Abiotic variables were determined in the sewage effluent and in the reservoir water. Results Biomass and N and P contents in the periphyton were significantly different among sampling sites. The highest nutrient concentrations were found in the sampling sites with effluent. The highest periphyton chlorophyll-a were found inside and after the macrophyte stand, while N and P contents were the highest in the effluent inlet and effluent. Conclusions In conclusion, N and P contents in the periphyton were associated with N and P availability, evidencing the ability of nutrient retention of the community. Our findings suggest that periphyton on artificial substrate can as a potential tool for removing N and P from the effluent from the sewage treatment system, contributing to minimizing the nutrient load discharged in a shallow reservoir.

Toxicity Assessment of Treated Sewage Effluent using the Zebrafish Embryo Model

Background: In a context of tremendous economic value, the management and protection of water resources in Qatar has long been a significant issue as part of the global wastewater management plan. The process is based on several stages of treatment in order to deliver high-quality effluent standard. Treated sewage effluent (TSE) can potentially be used for agriculture in Qatar and it should be biologically evaluated before releasing it to the environment. TSE water can be further filtered with techniques that include reverse osmosis, forward osmosis, and nanofiltration. Aim: This project aims to assess the toxicity of differently treated sewage effluent water on the environement using the zebrafish model. Our approach will also be relevant to the assessment of the water quality for agriculture use. Methods: Zebrafish embryos were cultured in different effluent water samples filtered with different techniques. Toxicicity of water was assessed via multiple assasys including: survival rate, tail flicking, and hatching rate. Cardiotoxicity assessment was performed via blood velocity, cardiac output and vessels diameter measurement in major vessels, as well as gene expression for heart failure markers of ANP and BNP by PCR. Results: Samples filtered via Reverse osmosis and nano-filtration resulted in most toxicity. Total dissolved solvent (TDS) measurements were also highest in those samples, suggesting these filteration techniques may result in release of toxic compounds to effluent water. Toxicity assessment is currently ongoing to confirm the findindgs. Conclusion: Utilization of TSE for environmental and agricultural purposes will have an economical value in the nation. It is critically important to determine the most efficient and less toxic ways of water filteration. Zebrafish is a practical model that can be used to assess water toxicity. This project aims to examine toxicity of effluent water filteration techniques using the zebrafish model.

Carbide Derived Carbon (CDC) as novel adsorbent for ibuprofen removal from synthetic water and treated sewage effluent

Purpose Pharmaceuticals are becoming one of the largest environmental concerns when it comes to the water treatment industry. Increased usage of these chemicals poses a serious risk to ecology and human health due to their leakage into surface waters. In the present study, carbide derived carbon (CDC) was used for the first time as a new adsorbent to remove ibuprofen from synthetic water and wastewater effluent. Methods The morphology, chemical composition, surface area and surface charge of the CDC particles were investigated using the transmission electron microscopy, scanning electron microscopy, energy dispersive spectroscopy, Fourier transform infrared spectroscopy, BET analysis and zeta potential measurements. The effects of CDC dosage, temperature, initial pH and agitation speed on the adsorption process were examined by using batch adsorption experiments. Moreover, the adsorption kinetics, thermodynamics, and isotherms were investigated. Results Adsorption and kinetic equilibrium data demonstrate that the adsorption of ibuprofen onto the CDC obeys the Langmuir isotherm model and the kinetics follow the pseudo-2nd order mechanism. The thermodynamic results reveal that ibuprofen adsorption is endothermic and spontaneous. The ibuprofen removal by CDC was mainly controlled by the electrostatic forces at high pH of the feed solution and by the dispersive interactions in acidic media. The ibuprofen removal is promoted at high temperature, high agitation speed and low pH. The highest adsorption capacity of ibuprofen onto the CDC was 367 mg/g at pH 3. Furthermore, the CDC efficiently removed ibuprofen from spiked treated sewage effluent. Conclusions The obtained data indicate that the CDC provides a fast and efficient adsorptive removal of ibuprofen both from a model aqueous solution and treated sewage effluent.