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Sludge reuse is one of the main challenges of waste management and an action with environmentally consequences that must be kept under control. The progress of civilization leaded to the globally increase of sludge production. WWTPs treatment technologies, sludge disposal/recovery and also quality control and toxicological involvements became parts of strategical actions at international level. The main disposal strategies for sludge management include agriculture or landscaping purposes, or final disposal. The accepted international policy is sludge application as organic fertilizer in agriculture. In this context, the research paper presents laboratory data used in decisional actions for the sludge land disposal. The study covers physical and chemical characterization of sludge resulted from Focsani WWTP, agriculture soil collected from around of Focsani WWTP and their leachates in compliance with national norms. In addition, the toxic effects on soil organisms (plants) were evaluated. Generally, soil and sludge quality meet the normed criteria for minimizing the potential impact on the environment. The leachate experiments showed the non-hazardous character on the soil properties of groundwater, the predicted impact being insignificant for the tested sludge / soil chemical composition. Ecotoxicological assessment of stabilized sludge showed inhibitory effects in the range of 25% to 100% on seed germination and root growth of plants Sorghum sacharatum, Sinapis alba and Lepidium sativum. In the range of 1% or 5% no significant inhibitory effect of sludge on plants growth was observed. Sorghum sacharatum showed the best growth, but there were no relevant differences between species. A saftey dose of 5% sludge mixed with agriculture soil (250 tonnes per hectare) was established. A monitoring program of sludge / soil quality and also ecotoxic evaluation was recomanded for the saftey of crops growth and health of living organisms including humans.

The cationic surfactants have various applications being found in personal care products, detergents, cleaning products, disinfectants, hair conditioners, etc. Cationic surfactants are presented in domestic or industrial wastewater, being very resistant pollutants to biodegradation during conventional wastewater treatment (WT) methods, which generated the need to develop new efficient alternative methods. One of the alternative to conventional WT methods involves the utilization of the adsorbent nanomaterials, which are highly efficient, easy to operate, environmental friendly and cost effective. In this study, it was investigated the adsorption process of a cationic surfactant, benzyldodecyldimethylammonium bromide (benzalkonium bromide) from wastewater on magnetite nanomaterial. The adsorption investigation of benzalkonium bromide was analyzed by TOC analysis and the maximum adsorption efficiency obtained was 91.4 %. The experimental data fitted very well with Langmuir model, the correlation coefficient (R2) being 0.9792.

Wastewater treatment plants are major interface between rural and urban activities and the natural environment with problems relating to the survival and transmission of the fecal bacteria into streams and rivers. The main goal of this paper was to showed the impact of WWTPs on fecal populations bacteria and their dissemination into the aquatic ecosystems. The sampling campaigns were conducted in 2019 where the hospital and WWTPs wastewater from three cities from the south-eastern part of Romania and the surface water of their emissaries were trimestral collected. The quantitative and qualitative analysis of total and fecal coliforms indicated the efficiency of wastewater treatment processes but at the same time, the contribution of contamination with hospital effluents has been demonstrated. Also, the microbiological results showed the selectivity of the destruction of fecal coliform bacteria between wastewater and surface water.

Surfactants represent the major class of chemicals used in the composition of detergents where the predominant groups are anionic surfactants. Because of the large utilization of detergents in different activities (agricultural, industrial, domestic) an important amount of surfactants can accumulate in the domestic and industrial wastewaters, that are discarded to wastewater-treatment plants (WWTP). Furthermore, surfactants could affect the process of biological wastewater treatment due the inhibition of activated sludge and subsequently the water bodies quality through discharge of WWTPs` effluents. In addition, the soil quality decreased through various modes of sludge applied. The concentrations of organic matters discharged in the wastewater systems from Romania have raised the attention of environmental authorities regarding the toxic impact of their components such as anionic surfactants on the environment. The present paper proposed to highlight the background of organic pollution from Romania through the monitoring of the organics amount in water by Chemical Oxygen Demand (COD) and by the specific indicator � Anionic Surfactants (AS). Temporal (winter, spring and summer, 2019) and spatial (six areas: West, North-West, North-East, East, South and South-West) monitoring of organic matter was performed. It has been found that the spatial and temporal variation of AS concentrations were well correlated with COD load, leading to the conclusion that surfactants represented an important part of the global organic matter.

The food dyes have a potential toxic effect on aquatic organisms which trigger the necessity of their removal from industrial or urban wastewaters. Many different removal methods were investigated for this purpose, but the ozonation and advanced oxidation processes (AOPs) were successfully applied in this field. However, the majority of studies emphasized that color removal by ozonation process did not report a complete mineralization of the dye and the resulted by-products may have a greater toxicity than the original compound. In this context, the paper presents a comparative ecotoxicity study of the dye Brilliant Blue FCF (BB FCF) before and after ozone treatment. The BB FCF toxic effect, before and after ozonation was investigated on crustacean (Daphnia magna), lethal or inhibitory concentrations for 50% of tested organisms (LC50 / EC50) were used to estimate the effect level. The dye showed no toxicity on crustacean (CL50/CE50]100mg/L) before ozonation. The ozonized solutions presented a high toxicity for crustaceans compared to initial dye due to the by-products occurrence.

Four coordination compounds of Pd(II), Pt(II) and Pt(IV) with usnic acid (H3AU) and 1-(o-tolyl)biguanide (TB) as ligands have been synthesized in view of their potential as antimicrobial, antifungal and antitumor agents. The metal complexes have been characterized by elemental and thermogravimetrical analyses, infrared and electronic spectra. Based on these studies, the following formulas have been proposed for the complexes: [Pd(TB)(H3AU)]PdCl4 (C1), [Pd(TB)(H2AU)] CH3COO (C2), [Pt(TB)(H2AU)Cl2]Cl (C3) and [Pt(TB)(H2AU)]Cl (C4), where H2AU is deprotonated usnic acid. The in vitro biological activities of the new complexes were tested against Staphylococcus aureus ATCC 25923, Pseudomonas aeruginosa ATCC 27853, Candida albicans ATCC 10231 and HeLa tumor cells. All complexes were found to have good biological properties and therefore they can be further explored in therapeutic applications.

The present paper aims to evaluate the toxic effects generated by conventional treated mine water as well as freshwater samples (Macris river) on primary producers (green algae, Selenastrum capricornutum) and primary consumers (planktonic crustaceans, Daphnia magna). Those organisms could be very realiable biological models to assess the toxic effect of mine waters on the environment. The green algae growth inhibition test (performed according to OECD201) and the acute immobilization test of freshwater crustaceans (Daphnia magna) (performed according to OECD 202) showed no growth inhibition or Daphnia magna immobilization / mortality during 72h and 48h incubation in presence of surface water samples from Macris river. The aqueous system with 1.89 g/L sulphate ion (SO42-) concentration, containing treated mine water mixed with freshwater sample (ratio 2.4:1), generated 100% toxic effect on crustaceans (Daphnia magna) after 48h incubation.

The objectives of the study were 1) to investigate the degree of pollution of phosphorus-loaded water using Lemna minor L. and 2) the absorption capacity of this organic compound by the Lemna minor L. aquatic plant, depending on the temperature parameter.

Various biocide technologies have been used successfully in water treatment applications for many years, but their constantly increased production and excessive usage has considerable environmental and economic impacts. In addition, the aggressive use of biocides in more and more fields such as agriculture, livestock growth, and fish farming increased the risk to public health. This measures can lead to the selection of pathogens insusceptible to the main available antimicrobials. Antimicrobials resistance is even more significant when cells are embedded in a biofilm especially in water systems. A variety of microorganisms can be found in swimming pool waters which may be introduced in a number of ways. The disinfection of bathing water is generally achieved by chlorine of chlorine-based products, but alternative more eco-friendly methods such as active oxygen are used more frequently. In this paper, compared the biocides efficiency of two compounds based on chlorine or active oxygen. Although it was assumed that the two biocides have the same mechanism of action and efficiency, we showed in this study that biocides efficiency depends on the bacterial membrane structure and the active oxygen had an increased efficacy against microorganisms compared to chlorine.

A preliminary stage in developing numerical simulations of a biological process for wastewater treatment consists in evaluating the kinetic parameters of the studied process. The study shows results obtained by experimental and numerical evaluation of mixed microalgae-bacteria granules kinetical parameters. The results showed that operational parameters modulated the main kinetic parameters of biological processes involved in removal of organic load and nutrients from wastewater such as biomass production coefficient, endogenous decomposition rate, specific peak rate of growth, semisaturation constant, specific rate of nitrification and the specific denitrification speed. These key parameters were determined over time to evaluate the performance of microbial populations in microalgae-bacteria granules in different operational conditions. Tests have been carried out for various wastewater compositions to determine the versatility and adaptability of the technology.

Three new samarium(III) complex compounds with chlorhexidine as ligand and mixed ligands chlorhexidine/o-phenanthroline have been prepared and characterized by elemental and thermogravimetrical analyses, infrared, electronic and luminescence spectra. The complexes corresponded to the formulas: [Sm(CHX)(NO3)2]� NO3, [Sm(CHX)(o-phen)2]� (NO3)3 and [Sm2(CHX)(o-phen)2(NO3)4]�(NO3)2, where CHX was the chlorhexidine. Chlorhexidine acted as neutral tetradentate NNNN donor, coordinating through the four imine nitrogen atoms. The two mixed ligands complexes showed a strong luminescent emission in solid state, characteristic of samarium(III) ion. The metal complexes and the chlorhexidine diacetate were in vitro evaluated for their antimicrobial activity against two Gram negative bacteria. The results revealed that all compounds were very effective in reducing the bacterial growth rate, even at low concentration.

The aim of this paper was to assess de ecotoxicity effects of four biocides, used as chemical disinfectants for swimming pool water treatment, on non-target organisms such as Daphnia magna and Heterocypris incongruens crustaceans. The tests showed a significant difference of sensitivity between species. The biocides, at the recommended disinfection doses, induced a very toxic or toxic effect on Daphnia magna, based on their mortality percentage. On the contrary, the observed ostracods lethal effects were generally less than 50% mortality and no significant growth inhibitions were observed. Overall, the ostracods had a higher tolerance to subacute doses, including disinfection doses of 20 mg/L (potassium mono persulfate), 5 mg/L (sodium dichloroisocyanurate), 8 mg/L (trichloroisocyanuric acid 90%) and 7 mg/L (trichloroisocyanuric acid 87-88%). In the context of a continuous biocides market expansion, the paper highlighted that our research proposed testing methods to obtain fast and accurate ecotoxicity data for a sustainable biocide production / authorization and also for an environmental hazard assessment.

In this present paper the behavior of two important pharmaceutical compounds, namely: nicotinic acid (vitamin PP/B3) and para-aminobenzoic acid (vitamin B10) to the transport through a liquid membrane of chloroform containing Aliquat 336 have been studied. The influence of operational parameters such as: solute concentration in the feed phase, stripping agent concentration in the stripping phase, transport time was monitored. The assessment of the obtained results allowed establishing of optimal transport conditions as well as identification of a kinetic transport model for nicotinic acid corresponding to consecutive irreversible 1st order reactions. The maximum transport efficiency was 96% and it was obtained at a concentration of 10-4 mol/L nicotinic acid in the feed phase and a concentration of 1 mol/L sodium hydroxide in the stripping phase. The transport time necessary to achieve this efficiency was 6 h. The results obtained led to important conclusions regarding the possibility of separating these two compounds. Analytical control of the process was done spectrophotometrically. The maximum absorbance was obtained at their characteristic wavelengths, namely 262 nm for nicotinic acid and respectively 267 nm for para-aminobenzoic acid.

Benzenthonium chloride (BEC, Hyamine 1622) is a quaternary ammonium surfactant with cationic properties widely used in cleaning, sanitation, and medical products that can become harmful to humans and also to the environment. This study aimed to evaluate its acute effects on Cyprinus carpio fish in terms of oxidative stress and morphological changes on hepatic tissue in order to show the sub-lethal toxicity of BEC. Fish were exposed to 1 mg/L BEC for 24, 48, and 96 h, and the liver samples were collected. The most significant changes were noticed after 96 h of exposure when the entire antioxidant enzyme system was affected. The activities of catalase, glutathione peroxidase, glutathione reductase, and glutathione S-transferase decreased by 44%, 31%, 30%, and 45%, respectively, compared to control. Glucose-6-phosphate dehydrogenase activity decreased by 29% after 96 h of control, inducing a reduction of NADPH formation which decreased by half the level of reduced glutathione, the main non-enzymatic antioxidant. These effects correlated with the raised value of lipid peroxidation after 96 h and the morphology changes on hepatic tissue, such as cytoplasmic vacuolization and nuclear hypertrophy that could affect the normal function of the liver. All of these results showed acute toxicity of BEC on C. carpio after 96 h of exposure, causing oxidative stress response at the hepatic level.

This study investigates the synergistic effects of ion exchange and biodegradation methods to remove the Acid Blue 193 also called Gryfalan Navy Blue RL (GNB) dye from wastewater. Ion exchange studies were performed using a strongly basic anion exchange resin Amberlite IRA 400. The equilibrium was characterized by a kinetic and thermodynamic points of view, establishing that the sorption of the GNB dye was subject to the Freundlich isotherm model with R2 = 0.8710. Experimental results showed that the activated resin can removed up to 93.4% when the concentration of dye solution is 5.62�10-2 mM. The biodegradation of the GNB was induced by laccase, an enzyme isolated from white-rot fungus. It was also analyzed the role of pH and dye concentration on GNB biodegradation, so 5�10-2 mM dye had a maximum discoloration efficiency of 82.9% at pH of 4. The laccase showed a very fast and robust activity reaching in a few minutes a Km value of 2.2�10-1mM. In addition, increasing the GNB concentration up to 8�10-1 mM did not triggered a substrat inhibition effect on the laccase activity. Overall, in this study we proposed a mixt physicochemical and biological approach to enhance the GNB removal and biodegradability from the wastewaters and subsequently the environment.

Metallic elements copper (Cu), zinc (Zn), nickel (Ni) and manganese (Mn) are some of the most commonly found in water and sediment samples collected from the Danube - Danube Delta. These elements are important as essential micronutrients, being normally present at low concentrations in biological organisms, but in high concentrations they become toxic with immediate and delayed effects. The role of this metals is still controversial, that�s why bioconcentration potential is so important. In this non-clinical study, we tested in vitro effect of heavy metals on carp, Cyprinus carpio, reproducing in vivo presence of Cu, Zn, Ni and Mn in the Romanian�s surface water. The toxicity tests were performed according to OECD 203 by detecting the average (50%) lethal concentration - LC50 on aquatic organisms (freshwater fish) at 96h. The results pointed out that, copper value for LC 50 at 96h was estimated as 3.4 mg/L (concentrations tested in the range of 0.1 - 4.75 mg/L). Zinc value for LC 50 at 96h was estimated as 20.8 mg/L (concentrations tested in the range of 0.028 � 29.6 mg/L). Nickel value for LC 50 at 96h was estimated as 40.1 mg/L (concentrations tested in the range of 0.008 - 84.5 mg/L). For manganese the mortality effects has recorded at LC 50 at 96h at estimated value higher than 53 mg/L (concentrations tested in the range of 0.04 - 53.9 mg/L). The accuracy of the testing metals concentration was insured by the screening of the dilution water, as well as food and control fish, acclimated in laboratory conditions.

During the past few decades, the anthropogenic activities induced worldwide changes in the ecological systems, including the aquatic systems. This work analysed the contamination level of groundwater resources from a rural agglomeration (Central-Western part of Prahova County) by biological and physico-chemical approaches. The study was performed during the autumn of 2016 on several sampling sites (four drilling wells, depth higher than 100 m supplying three villages; two wells lower than 10 m depth and one spring). The water quality was evaluated by comparison with the limit values of the drinking water quality legislation (Law no.458/2002) and the Order 621/2014 (applicable to all groundwater bodies of Romania). The results showed that phenols and metals (iron and manganese) exceeded the threshold values in all sampling sites. Moreover, the anthropogenic factors including agriculture, use of fertilizers, manures, animal husbandry led to an increase of the bacterial load, particularly at wells sites.

The growth of population has been linked with the increase usage of chemical compounds design for domestic and industrial use. At its turn, the increased amount of the chemical compound puts an enhanced stress on the environment. In such scenario, the waste management, including the wastewater treatment strategies have become an important part for the environmental protection. Unfortunately, the wastewater treatment procedures have several components which could be improved. Among them aeration process and biomass sedimentation have been the most stringent to tackle, since the aeration alone consume more than 60% from wastewater treatment energy cost. In this study, we proposed a new microalgae-bacteria activated sludge granule which could be an economical and technological solution to the above mentioned issues such as aeration and sedimentation. Moreover, during this study we characterized the physical, morphological and chemical characteristic of the newly formed granules by advances techniques such as electronic and correlative microscopy.

This paper depicts the research conducted at lab scale on aerobic granular sludge sequential biological reactors for wastewater treatment in order to assess the influence of operational parameters on the treatment performances and microbial diversity of the granules. The proposed objectives were reached by testing in similar reactor conditions different organic nitrogen and phosphorus loading rates. The study focused both on treatment performances as organic, nitrogen and phosphorus removal based on chemical analysis of main quality parameters and on diversity of microbial population in granules based on real-time polymerase chain reaction by targeting mainly the specific species or functional genes with high influence on process performance in terms of nitrification, denitrification and phosphorus removal.

Activated microalgae granules, as a technology at its initial steps, require sustained efforts for a better understanding of the intertrophic relationship between algae and bacteria. The activated algae granules samples from extensive lab-scale sequencing batch reactor experiments were selected for a total DNA extraction and analysis. A relative quantitative analysis of bacterial genes involved in nitrification, denitrification, phosphorus accumulation as well as genes belonging to microalgae was performed by real-time PCR / qPCR. Microscopic investigations of activated microalgae granule showed a gradual decrease of microalgae concentration, together with an increase in bacterial populations inside the granule.