J. M. Quiroga Alonso

Bio: J. M. Quiroga Alonso is an academic researcher from University of Cádiz. The author has contributed to research in topics: Wastewater & Reverse osmosis. The author has an hindex of 7, co-authored 12 publications receiving 328 citations.

Modelling of reactivation after UV disinfection: Effect of UV-C dose on subsequent photoreactivation and dark repair

Abstract: The increased use of UV radiation as a wastewater treatment technology has stimulated studies of the repair potential of microorganisms following treatment. In this study, samples of unfiltered secondary effluent were irradiated with seven levels of UV-C doses (50–200 mW s/cm 2 ) from six low-pressure lamps in an open-channel UV disinfection system. Following irradiation, samples were incubated at 20 °C under photoreactivating light or in darkness. Samples were analysed for 240 min following incubation. The logistic model is proposed to explain the relation between photoreactivation and the UV-C dose received by the microorganisms. That model accurately fitted the data obtained in photoreactivation experiments, permitting interpretation of the estimated kinetic parameters: S m and k 2 . In the experiments carried out in darkness, a slight reactivation is observed ( S m and k 2 , in both photoreactivation and darkness, show an exponential dependence on the UV-C inactivating dose. It is possible to predict their values, and hence the reactivation curve, from the equations proposed in this work.

Oxidation mechanisms of amoxicillin and paracetamol in the photo-Fenton solar process.

Abstract: The present study shows the results of solar photo-Fenton oxidation of paracetamol (PCT) and amoxicillin (AMX). Fe2(SO4)3 was used as the source of iron and EDDS as the iron complexing agent, employing different doses of hydrogen peroxide. Two aqueous matrices, a synthetic wastewater and real wastewater from El Ejido WWTP effluent (Almeria) were used. In all cases, the process was operated under conditions of natural sunlight. Results showed that the degradation of both drugs is favoured when the aqueous matrix presents low concentration of carbonates. Under the conditions studied here, degradation percentages above 90% were obtained in the synthetic wastewater and 80% in the actual effluent. The degradation products were determined using liquid chromatography coupled to high-resolution mass spectrometry with hybrid quadrupole time-of-flight analyser. The intermediates detected throughout the oxidative process for both micro-contaminants were mainly products of hydroxylation reactions. The toxicity of the samples was determined using the bacterium Vibrio fischeri. In the acute toxicity test, it was observed that the bacteria did not undergo inhibition in any of the cases. However, chronic toxicity studies showed that the higher the Hydraulic Retention Time (HRT) employed in the assays, the higher the bacterial inhibition.

Comparative studies of reverse osmosis membranes for wastewater reclamation

Abstract: Interest in wastewater reclamation and reuse has increased considerably over the past several years in Spain. However, the implementation of involving membrane-based advanced treatment and groundwater recharge schemes is still limited. The goal of this paper is to show part of the studies conducted using an experimental pilot plant (output: 100 m 3 /d) in Chiclana de la Frontera, Province of Cadiz, southern Spain. The purpose pilot-plant study was to define the optimum conditions for physicochemical pretreatment of secondary effluents for successful reverse osmosis operation for groundwater recharge. The performance of cellulose acetate and two thin-film composite membranes was studied. Several pretreatment levels were used in order to optimise economic issues. Comparative analyses of the secondary effluent and the reclaimed wastewater for groundwater recharge were made in order to study the efficiency of the treatment sequence used and the feasibility of the processes studied. Membrane rejection characteristics are showed to be an important barrier to the presence of pollutants and micro-pollutants in reclaimed wastewater. Finally, the high quality of reclaimed wastewater allows it to be used with safety in groundwater recharge and other reuse applications without restrictions.

An assessment of heavy metal contamination in surface sediment using statistical analysis.

Abstract: The distribution and accumulation of heavy metals in the sediments, especially those nearest of wastewater discharges of south of Spain, were investigated. Sediment samples from 14 locations were collected and characterised for metal content (e.g. Ni, Cu, Zn, Cr, Pb, Mn, Cd and Hg), organic carbon, total nitrogen, total phosphorous, n-hexane-extractable material, carbonates and grain size. Concentration data were processed using correlation analysis and factor analysis. The correlation analysis of concentrations data showed important positive correlations among organic carbon, total phosphorus, Cu, Zn, Cd and Hg, otherwise weak correlations among Mn, Cr, Ni and CO3 2 − , indicating that these metals have complicated geochemical behaviours. The use of statistical factor analysis also confirmed these results. Sediments pollution assessment was carried out using geoaccumulation and metal pollution indexes (MPI8). The results revealed that sediments of Cadiz bay and Sancti Petri channel were uncontaminated with the studied metals.

Use of microbial activity parameters for determination of a biosolid stability index.

Abstract: Variations in microbial activity during the aerobic digestion of sludge generated at wastewater treatment plants were studied. Results obtained by the measurement of enzymatic activity and microbiological parameters were compared with those determined by traditional methods (COD, suspended solids, etc.). Their variation with digestion time was monitored for batch digestion over a period of 135 days. The relationship between these measurements and control parameters of the sludge was also investigated. It was found that the traditional physicochemical and microbiological parameters present a series of problems which detract from their usefulness. The enzymatic parameters dehydrogenase activity (primary metabolism) and esterase activity (secondary metabolism) are better able to characterise the process, and the ratio of these two variables may be used to estimate the degree of endogenesis and, consequently, the degree of stability of the aerobic sludge digestion. In addition, these techniques are swift and simple to employ.

The biodegradation of surfactants in the environment

Abstract: The possible contamination of the environment by surfactants arising from the widespread use of detergent formulations has been reviewed. Two of the major surfactants in current use are the linear alkylbenzene sulphonates (LAS) and the alkyl phenol ethoxylates (APE). These pass into the sewage treatment plants where they are partially aerobically degraded and partially adsorbed to sewage sludge that is applied to land. The biodegradation of these and a range of other surfactants both in wastewater treatment plants and after discharge into natural waters and application to land resulting in sewage sludge amended soils has been considered. Although the application of sewage sludge to soil can result in surfactant levels generally in a range 0 to 3 mg kg −1 , in the aerobic soil environment a surfactant can undergo further degradation so that the risk to the biota in soil is very small, with margins of safety that are often at least 100. In the case of APE, while the surfactants themselves show little toxicity their breakdown products, principally nonyl and octyl phenols adsorb readily to suspended solids and are known to exhibit oestrogen-like properties, possibly linked to a decreasing male sperm count and carcinogenic effects. While there is little serious risk to the environment from commonly used anionic surfactants, cationic surfactants are known to be much more toxic and at present there is a lack of data on the degradation of cationics and their fate in the environment.

A review of reverse osmosis membrane fouling and control strategies

Abstract: Reverse osmosis (RO) membrane technology is one of the most important technologies for water treatment. However, membrane fouling is an inevitable issue. Membrane fouling leads to higher operating pressure, flux decline, frequent chemical cleaning and shorter membrane life. This paper reviews membrane fouling types and fouling control strategies, with a focus on the latest developments. The fundamentals of fouling are discussed in detail, including biofouling, organic fouling, inorganic scaling and colloidal fouling. Furthermore, fouling mitigation technologies are also discussed comprehensively. Pretreatment is widely used in practice to reduce the burden for the following RO operation while real time monitoring of RO has the advantage and potential of providing support for effective and efficient cleaning. Surface modification could slow down membrane fouling by changing surface properties such as surface smoothness and hydrophilicity, while novel membrane materials and synthesis processes build a promising future for the next generation of RO membranes with big advancements in fouling resistance. Especially in this review paper, statistical analysis is conducted where appropriate to reveal the research interests in RO fouling and control.

Application of ultraviolet light-emitting diodes (UV-LEDs) for water disinfection: A review

Abstract: Ultraviolet (UV) disinfection is an effective technology for the inactivation of pathogens in water and is of growing interest for industrial application. A new UV source - ultraviolet light-emitting diode (UV-LED) - has emerged in the past decade with a number of advantages compared to traditional UV mercury lamps. This promising alternative raises great interest in the research on application of UV-LEDs for water treatment. Studies on UV-LED water disinfection have increased during the past few years. This article presents a comprehensive review of recent studies on UV-LEDs with various wavelengths for the inactivation of different microorganisms. Many inconsistent and incomparable data were found from published studies, which underscores the importance of establishing a standard protocol for studying UV-LED inactivation of microorganisms. Different UV sensitivities to UV-LEDs and traditional UV lamps were observed in the literature for some microorganisms, which requires further investigation for a better understanding of microorganism response to UV-LEDs. The unique aspects of UV-LEDs improve inactivation effectiveness by applying LED special features, such as multiple wavelengths and pulsed illumination; however, more studies are needed to investigate the influencing factors and mechanisms. The special features of UV-LEDs offer the flexibility of novel reactor designs for a broad application of UV-LED reactors.

Enrichment and geo-accumulation of heavy metals and risk assessment of sediments of the Kurang Nallah—Feeding tributary of the Rawal Lake Reservoir, Pakistan

Abstract: Heavy metal concentrations in sediments of the Kurang stream: a principal feeding tributary of the Rawal Lake Reservoir were investigated using enrichment factor (EF), geoaccumulation index (Igeo) and metal pollution index (MPI) to determine metal accumulation, distribution and its pollution status. Sediment samples were collected from twenty one sites during two year monitoring in pre- and post-monsoon seasons (2007-2008). Heavy metal toxicity risk was assessed using Sediment Quality Guidelines (SQGs), effect range low/effect range median values (ERL/ERM), and threshold effect level/probable effect level (TEL/PEL). Greater mean concentrations of Ni, Mn and Pb were recorded in post-monsoon season whereas metal accumulation pattern in pre-monsoon season followed the order: Zn>Mn>Ni>Cr>Co>Cd>Pb>Cu>Li. Enrichment factor (EF) and geoaccumulation (Igeo) values showed that sediments were loaded with Cd, Zn, Ni and Mn. Comparison with uncontaminated background values showed higher concentrations of Cd, Zn and Ni than respective average shale values. Concentrations of Ni and Zn were above ERL values; however, Ni concentration exceeded the ERM values. Sediment contamination was attributed to anthropogenic and natural processes. The results can be used for effective management of fresh water hilly streams of Pakistan.

Removal of total ammonia nitrogen (TAN), nitrate and total organic carbon (TOC) from aquaculture wastewater using electrochemical technology: A review

Abstract: article i nfo Protein rich wastes from aquaculture systems result in total ammonia nitrogen (TAN), total organic carbon (TOC) and biochemical oxygen demand (BOD) A number of conventional approaches have been adopted for the removal of these wastes in aquaculture ponds and hatcheries with varying degrees of success but they face critical problems such as membrane fouling, high cost or the generation of toxic by-products To overcome such issues, electrochemical technology is commonly employed The advantages of electrochemi- cal treatment include high efficiency, ambient operating conditions, small equipment sizes, minimal sludge generation and rapid start-up An even better system involves bio-electrochemical reactors (BERs), which have the potential to generate energy from wastewater (by means of microbial fuel cells) or a valuable prod- uct such as hydrogen (using microbial electrolysis cells) Mechanisms of cathodic nitrate reduction and anod- ic oxidation in electrochemical and bio-electrochemical technology are reported in this review Also some work on the simultaneous removal of nitrate and organic matter by Electro-Fenton and microbial fuel cells are elaborated upon It is apparent that BERs can remove contaminants at high efficiencies (≈99%) whilst giving least impact upon the environment