Showing papers on "Effluent published in 2017"

Extraction and identification of microplastic particles from secondary wastewater treatment plant (WWTP) effluent

Abstract: Although studies on microplastics in wastewater treatment plant (WWTP) treated effluent have recently been published, no standard method for sampling, identification and quantification of microplastics has been established, which complicates the comparison of results across various studies. This paper presents an attempt to optimize the Wet Peroxide Oxidation (WPO) digestion procedure applicable to wastewater effluent matrices and underscores unique challenges and interferences that analysts face when attempting to quantify microplastic particles in wastewater.

A review of biogas production from palm oil mill effluents using different configurations of bioreactors

Abstract: Palm oil mill effluent (POME) is generated from the sterilization, condensation and hydrocycloning of palm oil in mills. If the effluent is discharged into the aquatic and terrestrial ecosystem without treatment, it could lead to high biological oxygen demand (BOD), chemical oxygen demand (COD) and acidic pH of the receiving waters. Biogas consisting mostly of methane, carbon dioxide, and to a lesser hydrogen has been produced through anaerobic treatment of this toxic effluent. The process of biogas production involves microbial synthesis involving hydrolysis, acidogenesis, acetogenesis and methanogenesis. Biogas is formed during anaerobic degradation of POME by indigenous microbial communities. This review updates the current state of art of biogas production through anaerobic digestion of POME using different configurations of reactors such as fluidized bed reactor, anaerobic filtration, up-flow anaerobic sludge blanket (UASB) reactor, anaerobic contact digestion, up-flow anaerobic sludge fixed-film (UASFF) reactor, modified anaerobic baffled bioreactor (MABB), anaerobic baffled bioreactor (ABR), continuous stirred tank reactor (CSTR), expanded granular sludge bed (EGSB) reactor, Ultrasonicated membrane anaerobic system (UMAS), Ultrasonic-assisted Membrane Anaerobic System (UAMAS), membrane anaerobic system (MAS)and upflow anaerobic sludge blanket reactor (UASBR). The factors that influences biogas yield during treatment include pH, temperature (environmental factors), organic loading rate (OLR), hydraulic retention time (HRT), mixing rate, pressure, equilibrium, nutrient and microbial activities (Internal factors). Based on this study, UAMAS is the best configuration for methane production from POME during anaerobic treatment. Biogas from POME could contribute to energy sources of oil palm producing nations, while preventing the attendant environmental impacts associated with its disposal.

Microalgae-based advanced municipal wastewater treatment for reuse in water bodies

Abstract: Reuse of secondary municipal effluent from wastewater treatment plants in water bodies could effectively alleviate freshwater resource shortage. However, excessive nutrients must be efficiently removed to prevent eutrophication. Compared with other means of advanced wastewater treatment, microalgae-based processes display overwhelming advantages including efficient and simultaneous N and P removal, no requirement of additional chemicals, O2 generation, CO2 mitigation, and potential value-added products from harvested biomass. One particular challenge of microalgae-based advanced municipal wastewater treatment compared to treatment of other types of wastewater is that concentrations of nutrients and N:P ratios in secondary municipal effluent are much lower and imbalanced. Therefore, there should be comprehensive considerations on nutrient removal from this specific type of effluent. Removal of nutrients and organic substances, and other environmental benefits of microalgae-based advanced municipal wastewater treatment systems were summarized. Among the existing studies on microalgal advanced nutrient removal, much information on major parameters is absent, rendering performances between studies not really comparable. Mechanisms of microalgae-based nitrogen and phosphorus removal were respectively analyzed to better understand advanced nutrient removal from municipal secondary effluent. Factors influencing microalgae-based nutrient removal were divided into intrinsic, environmental, and operational categories; several factors were identified in each category, and their influences on microalgal nutrient removal were discussed. A multiplicative kinetic model was integrated to estimate microalgal growth-related nutrient removal based majorly on environmental and intrinsic factors. Limitations and prospects of future full-scale microalgae-based advanced municipal wastewater treatment were also suggested. The manuscript could offer much valuable information for future studies on microalgae-based advanced wastewater treatment and water reuse.

Microplastics in a freshwater environment receiving treated wastewater effluent

Abstract: Small plastic fragments (microplastics or solid particles <5 mm in size or “microbeads” used in personal care products and cosmetics) may ultimately find their way into aquatic environments. We studied the presence of microplastics (particle sizes 53–105 μm and 106–179 μm) spatially and temporally in 3 connected urban lakes being fed by treated wastewater effluent in Lubbock, Texas. These lakes also serve as drainage during storm events. Water samples from drainage playa wetlands within the city were also collected. Our interest was in determining the presence or absence of microplastics in a freshwater environment as well as the source apportionment between personal care products (via wastewater) and discarded plastics (via runoff). Results showed that average concentrations of microplastics in samples collected from lakes ranged from 0.79 ± 0.88 mg/L to 1.56 ± 1.64 mg/L for the 53–105 μm size fraction and from 0.31 ± 0.72 mg/L to 1.25 ± 1.98 mg/L for the 106–179 μm size fraction. For samples collected from playa wetlands, average microplastic concentrations ranged from 0.64 ± 0.92 mg/L to 5.51 ± 9.09 mg/L for the 53–105 μm size fraction and from nondetectable (ND) to 1.79 ± 3.04 mg/L for the 106–179 μm size fraction. Our results (based on comparison of microplastic masses) suggest that urban runoff also contributes microplastics to surface water in addition to the treated wastewater effluent (in this particular case). The present findings may assist in adopting additional monitoring efforts and provide information on the potential contribution of secondary microplastic input into aquatic environments. Integr Environ Assess Manag 2017;13:528–532. © 2017 SETAC

Advanced oxidation processes for the treatment of tannery wastewater

Abstract: This study has focused on the treatment of real tannery effluent using different advanced oxidation processes in lab and pilot scale studies. Periodic monitoring was conducted for five months to identify the performance at different stages of treatment in the CETP. Monthly monitoring analysis shows that ratio of biochemical oxygen demand (BOD) and chemical oxygen demand (COD) were about 0.1–0.25. It was observed that even after physicochemical treatment the sample had a low biodegradability index (BDI). For this reason, more efficient methods of advanced oxidation processes like Fenton, Ozonation have been experimented with primary settling tank (PST) effluent to improve the biodegradation in the successive activated sludge process and secondary settling tank (SST) effluent to remove the residual inorganics. Sample collection and analysis were performed using standard methods of analysis. Pollutant removal efficiency was measured in terms of reduction in COD and Total Organic Carbon (TOC). The purification effect obtained by Advanced Oxidation Processes (AOPs) was better in Ozone when compared to Fenton. A three step process of (coagulation + aeration + O 3 ) resulted in 80–90% reduction of COD. Coagulation, extended aeration followed by ozonation was recognized as the best method of treatment of tannery wastewater. Lab scale and pilot scale studies were done with real tannery wastewater effluents and the economics of the treatment processes were evaluated.

Slow sand filtration for water and wastewater treatment – a review

Abstract: Water pollution is a serious global issue. Various technologically advanced treatment methodologies, for example, activated sludge process, upflow anaerobic sludge blanket, membrane bioreactor, trickling filter, rotating biological contractor, oxidation ditch, are widely studied, well documented and adopted in practice. However, attention to promising low-investment-cost technologies, such as slow sand filtration (SSF) techniques, is surprisingly miniscule. SSF (at a flow rate of 0.1–0.2 m3/h) is quite effective water treatment technology. It is also efficient in removing coliform microorganisms such as Giardia, Cryptosporidium, Salmonella, Escherichia coli, total coliform (TC) and fecal coliform, fecal streptococci, bacteriophage, MS2 virus from water/wastewater. Apart from reduction of pathogenic load, which is ascribed to the biological processes, SSF can efficiently remove turbidity, suspended solids and toxic metals in treated water. The SSF treated effluent conforms to the discharge standard...

A green solar photo-Fenton process for the elimination of bacteria and micropollutants in municipal wastewater treatment using mineral iron and natural organic acids

Abstract: In this investigation, a new, green photo-Fenton process for wastewater treatment is proposed, involving the use of a natural iron source and natural additives, deriving from wastes, acting as iron chelators. The use of mineral iron as precursor in the photo-Fenton process, instead of iron salts, was still able to promote E. coli inactivation. Furthermore, the addition of four low weight organic acids (citric, tartaric, ascorbic and caffeic) showed a significant enhancement of the process, reaching total inactivation except for caffeic acid, which showed no significant effects. Two natural products, rich in the promising organic acids were tested as additives, lime and orange juice, plus their infusion. Lime-based additives showed better results compared to orange-based ones, which could be attributed to the excessive addition of organic matter in the orange systems. The formation of photoactive complexes with the mineral iron and the organic acids from the natural products induced the production of reactive species and ferrous ion, sustaining a homogeneous Fenton reaction. Finally, the proposed modified process was tested against different secondary effluents from a municipal wastewater treatment plant. Total bacterial inactivation was reached in the lime-based system, with no visible microorganism regrowth after 48 h. Additionally, the process was able to eliminate 40% of the total identified micropollutants of the secondary effluent reaching almost 50% of removal of the total effluent organic matter.

Occurrence of naproxen, ibuprofen, and diclofenac residues in wastewater and river water of KwaZulu-Natal Province in South Africa.

Abstract: The present paper reports a detailed study that is based on the monitoring of naproxen, ibuprofen, and diclofenac in Mbokodweni River and wastewater treatment plants (WWTPs) located around the city of Durban in KwaZulu-Natal Province of South Africa. Target compounds were extracted from water samples using a multi-template molecularly imprinted solid-phase extraction prior to separation and quantification on a high-performance liquid chromatography equipped with photo diode array detector. The analytical method yielded the detection limits of 0.15, 1.00, and 0.63 μg/L for naproxen, ibuprofen, and diclofenac, respectively. Solid-phase extraction method was evaluated for its performance using deionized water samples that were spiked with 5 and 50 μg/L of target compounds. Recoveries were greater than 80% for all target compounds with RSD values in the range of 4.1 to 10%. Target compounds were detected in most wastewater and river water samples with ibuprofen being the most frequently detected pharmaceutical. Maximum concentrations detected in river water for naproxen, ibuprofen, and diclofenac were 6.84, 19.2, and 9.69 μg/L, respectively. The concentrations of target compounds found in effluent and river water samples compared well with some studies. The analytical method employed in this work is fast, selective, sensitive, and affordable; therefore, it can be used routinely to evaluate the occurrence of acidic pharmaceuticals in South African water resources.