Effluent Dilution Research Articles

Determining the zone of impact of norovirus contamination in shellfish production areas through microbiological monitoring and hydrographic analysis

Norovirus (NoV) contamination of filter feeding bivalve shellfish is a well-recognised human health threat when shellfish are grown in sewage polluted waters. To date, the identification of high risk zones around sewage discharges in shellfish production areas (SPAs) has not been based on NoV data. This study utilised molecular methods for NoV analysis, combined with hydrographic studies, to determine the relationship between NoV concentrations in shellfish and sewage effluent dilution. Cages with mussels and oysters were placed at different distances downstream of sewage discharges in two coastal sites in England. The shellfish were tested for concentrations of NoV (genogroups I and II) and E. coli. Drogue tracking and dye tracing studies were conducted to quantify the dispersion and dilution of sewage effluent in the SPAs. Significant negative associations were found between both total concentrations of NoV (GI + GII) and E. coli and sewage effluent dilution in the SPAs. The total NoV concentrations predicted by the model at 300:1, 1000:1 and 5000:1 ratios of estuarine water to sewage effluent were 1200; 600; and 200 copies/g, respectively. The estimated area of NoV contamination varied according with local pollution source impacts and hydrographic characteristics. The results help to inform the derivation of sewage discharge buffer zones as a control measure for mitigating risk from human NoV contamination in SPAs.

Risks associated with the environmental release of pharmaceuticals on the U.S. Food and Drug Administration “flush list”

A select few prescription drugs can be especially harmful and, in some cases, fatal with just one dose when not used as prescribed. Therefore, the U. S. Food and Drug Administration (FDA) recommends that expired, unwanted, or otherwise unused portions of most of these drugs be disposed of quickly through a take-back program. If such an option is not readily available, FDA recommends that they be flushed down the sink or toilet. The goal of the current investigation was to evaluate the ecological and human-health risks associated with the environmental release of the 15 active pharmaceutical ingredients (APIs) currently on the FDA “flush list”. The evaluation suggests that even when highly conservative assumptions are used—including that the entire API mass supplied for clinical use is flushed, all relevant sources in addition to clinical use of the API are considered, and no metabolic loss, environmental degradation, or dilution of wastewater effluents are used in estimating environmental concentrations—most of these APIs present a negligible eco-toxicological risk, both as individual compounds and as a mixture. For a few of these APIs, additional eco-toxicological data will need to be developed. Using similar conservative assumptions for human-health risks, all 15 APIs present negligible risk through ingestion of water and fish.

Heavy metal pollution due to coal washery effluent and its decontamination using a macrofungus, Pleurotus ostreatus

Release of the effluent generated during washing of coal became a major problem for coal industries due to presence of many toxic metals and other pollutants. These effluents are the main source of pollution in rivers and other water bodies. Therefore in this study, we tried to analyse the toxicity of coal washery effluent (CWE) collected from one of the washery plant situated in Dhanbad, India. CWE was found to be very toxic containing large amount of suspended particles and many heavy metals above than their permissible limits. Mycoremediation of CWE was also performed to decontaminate heavy metals from the CWE using a macrofungi Pleurotus ostreatus. Efficiency of Pleurotus for remediation of heavy metals was found to be highest in the 50% diluted effluent (57.2% Mn, 82.6% Zn, 98.0% Ni, 99.9% Cu, 99.3% Co, 99.1% Cr, 89.2% Fe and 35.6% Pb) followed by 25% diluted effluent (33.0% Mn, 55.1% Zn, 97.8% Ni, 99.7% Cu, 97% Co, 84.4% Cr, 87.1% Fe and 73.4% Pb) and raw effluent (23.3% Mn, 73.1% Zn, 78.7% Ni, 87.5% Cu, 59.3% Co, 64.6% Cr, 34.6% Fe and 11.3% Pb) respectively. Increased activity of antioxidant enzymes, lipid peroxidation, concentration of metallothionein proteins and changes in peaks of FTIR spectra were also observed in fungal mycelia grown on the CWE containing media due to accumulation of different metals. Overall this study suggests that Pleurotus can be used as promising option for removal of heavy metals from the effluent released from washery plants and dilution of effluent could increase the efficiency of remediation.

The use of saline aquaculture effluent for production of Enterolobium contortisiliquum seedlings.

The use of aquaculture effluent for irrigation of field crops has been suggested as the most appropriate biological method for treatment of this effluent. However, using it for irrigation of tree species in seedling nurseries might be a better alternative to avoid soil salinization and groundwater contamination in agricultural fields. This paper aimed at assessing the production of Enterolobium contortisiliquum seedlings under irrigation with saline aquaculture effluent. The experiment was carried out in a randomized complete block design with four replicates and four seedlings per experimental unit. Each replicate was daily irrigated with five solutions containing different concentrations of saline aquaculture effluent diluted with freshwater (0, 25, 50, 75 and 100% effluent). Despite increasing substrate salinity, the dilution of saline aquaculture effluent in the irrigation water promoted greater shoot growth and higher total dry weight in E. contortisiliquum. Moreover, seedlings treated with low concentrations of this effluent increased their leaf area expansion and chlorophyll content. Therefore, the use of solutions containing 25 and 50% effluent allowed the production of high-quality seedlings. These results suggest that saline aquaculture effluent can be reused to irrigate tree species, enabling a successful integration of aquaculture and agriculture and reducing environmental impacts of improper effluent disposal.

Exposure to wastewater effluent affects fish behaviour and tissue-specific uptake of pharmaceuticals

Pharmaceutical active compounds (PhACs) are increasingly being reported in wastewater effluents and surface waters around the world. The presence of these products, designed to modulate human physiology and behaviour, has created concern over whether PhACs similarly affect aquatic organisms. Though laboratory studies are beginning to address the effects of individual PhACs on fish behaviour, few studies have assessed the effects of exposure to complex, realistic wastewater effluents on fish behaviour. In this study, we exposed a wild, invasive fish species—the round goby (Neogobius melanostomus)—to treated wastewater effluent (0%, 50% or 100% effluent dilutions) for 28days. We then determined the impact of exposure on fish aggression, an important behaviour for territory acquisition and defense. We found that exposure to 100% wastewater effluent reduced the number of aggressive acts that round goby performed. We complimented our behavioural assay with measures of pharmaceutical uptake in fish tissues. We detected 11 of 93 pharmaceutical compounds that we tested for in round goby tissues, and we found that concentration was greatest in the brain followed by plasma, then gonads, then liver, and muscle. Fish exposed to 50% and 100% effluent had higher tissue concentrations of pharmaceuticals and concentrated a greater number of pharmaceutical compounds compare to control fish exposed to no (0%) effluent. Exposed fish also showed increased ethoxyresorufin-O-deethylase (EROD) activity in liver tissue, suggesting that fish were exposed to planar halogenated/polycyclic aromatic hydrocarbons (PHHs/PAHs) in the wastewater effluent. Our findings suggest that fish in effluent-dominated systems may have altered behaviours and greater tissue concentration of PhACs. Moreover, our results underscore the importance of characterizing exposure to multiple pollutants, and support using behaviour as a sensitive tool for assessing animal responses to complex contaminant mixtures, like wastewater effluent.

Toxic compounds biodegradation and toxicity of high strength wastewater treated under elevated nitrogen concentration in the activated sludge and membrane bioreactor systems

This research has assessed the removal efficiencies of toxic compounds in the high strength wastewater (the leachate and agriculture wastewater mixture) using the activated sludge (AS) and membrane bioreactor (MBR) technologies under two carbon to nitrogen (C/N) ratios (C/N 14 and 6) and two toxic compounds concentrations (8–396μg/L and 1000μg/L). In addition, the toxicity evaluations of the AS and MBR effluents to the aquatic environment were undertaken at five effluent dilution ratios (10, 20, 30, 50 and 70% v/v). The findings indicate that the AS treatment performance could be enhanced by the elevation of the nitrogen concentration. Specifically, the C/N 6 environment helps promote the bacterial growth, particularly heterotrophic nitrifying bacteria (HNB) and nitrifying bacteria (NB), which produce the enzymes crucial to the toxic compounds degradation. The improved biodegradation makes the effluents less toxic to the aquatic environment, as evidenced by the lower mortality rates of both experimental fish species raised in the nitrogen-elevated diluted AS effluents. On the other hand, the elevated nitrogen concentration minimally enhances the MBR treatment performance, given the fact that the MBR technology is in itself a biological treatment scheme with very high compounds removal capability. Despite its lower toxic compounds removal efficiency, the AS technology is simple, inexpensive and operationally-friendly, rendering the system more applicable to the treatment operation constrained by the financial, manpower and technological considerations.

Dynamic response of land use and river nutrient concentration to long-term climatic changes

The combined indirect and direct impacts of land use change and climate change on river water quality were assessed. A land use allocation model was used to evaluate the response of the catchment land use to long-term climatic changes. Its results were used to drive a water quality model and assess the impact of climatic alterations on freshwater nitrate and phosphorus concentrations. Climatic projections were employed to estimate the likelihood of such response. The River Thames catchment (UK) was used as a case-study. If land use is considered as static parameter, according to the model results, climate change alone should reduce the average nitrate concentration, although just by a small amount, by the 2050s in the Lower Thames, due to reduced runoff (and lower export of nitrate from agricultural soils) and increased instream denitrification, and should increase the average phosphorus concentration by 12% by the 2050s in the Lower Thames, due to a reduction of the effluent dilution capacity of the river flow. However, the results of this study also show that these long-term climatic alterations are likely to lead to a reduction in the arable land in the Thames, replaced by improved grassland, due to a decrease in agriculture profitability in the UK. Taking into account the dynamic co-evolution of land use with climate, the average nitrate concentration is expected to be decreased by around 6% by the 2050s in both the upper and the lower Thames, following the model results, and the average phosphorus concentration increased by 13% in the upper Thames and 5% in the lower Thames. On the long term (2080s), nitrate is expected to decrease by 9% and 8% (upper and lower Thames respectively) and phosphorus not to change in the upper thames and increase by 5% in the lower Thames.

Characterisation of coal washery effluent and optimisation of coagulation behaviour of Moringa oleifera seed as a coagulant

The huge quantity of effluent generated in coal washing processes contains large amount of suspended and dissolved solids, clay minerals, coal fines and other impurities associated with raw coal. The present system of recirculation of the effluent is found to be ineffective in removing colloidal fines, which is the major part of the impurities present in washery effluent. Hence, there is a need for the assessment of a better technique for an efficient removal of these impurities. This study deals with detailed characterisation of coal washery effluent and fine particles present in it. For efficient removal of impurities, the suitability of biocoag-flocculation process using Moringa oleifera seed biomass as a natural coagulant was examined. Various doses of M. oleifera ranging from 0.2 to 3mL/L were used in order to determine the optimal conditions. The impact of the variations in pH of the effluent (2-10), contact time (5-30min), settlement time (5-50min), temperature (10-50°C) and the effluent dilution (1:0-1:5) was also assessed to optimise the treatment process. Post treatment analysis was carried out for determination of the different parameters such as pH, conductivity, turbidity, solids and settling velocity. Excellent reduction in turbidity (97.42%) and suspended solids (97.78%) was observed at an optimum dose of M. oleifera seed coagulant of 0.8mL/L with an optimum contact time of 15 and at 20min of settling time. In comparison with very few past studies of M. oleifera in the treatment of coal washery effluent with high dose and inadequate removal, this study stands to be a major highlight with low dose and high removal of the impurities. M. oleifera coagulant is considered to be an environment-friendly material, therefore, its application is recommended for simple and efficient treatment of coal washery effluent.

Bioretention storm water control measures decrease the toxicity of copper roof runoff.

The present study evaluated the ability of 2 different bioretention storm water control measures (SCMs), planter boxes and swales, to decrease the toxicity of sheet copper (Cu) roofing runoff to Daphnia magna. The present study quantified changes in storm water chemistry as it passed through the bioretention systems and utilized the biotic ligand model (BLM) to assess whether the observed D. magna toxicity could be predicted by variations found in water chemistry. Laboratory toxicity tests were performed using select storm samples with D. magna cultured under low ionic strength conditions that were appropriate for the low ionic strength of the storm water samples being tested. The SCMs decreased toxicity of Cu roof runoff in both the BLM results and the storm water bioassays. Water exiting the SCMs was substantially higher than influent runoff in pH, ions, alkalinity, and dissolved organic carbon and substantially lower in total and dissolved Cu. Daphnids experienced complete mortality in untreated runoff from the Cu roof (the SCM influent); however, for planter and swale effluents, survival averaged 86% and 95%, respectively. The present study demonstrated that conventional bioretention practices, including planter boxes and swales, are capable of decreasing the risk of adverse effects from sheet Cu roof runoff to receiving systems, even before considering dilution of effluents in those receiving systems and associated further reductions in copper bioavailability. Environ Toxicol Chem 2017;36:1680-1688. © 2016 SETAC.

Determination of buildup and dilution of wastewater effluent in shellfish growing waters through a modified application of super-position

Since 1925, dilution analysis has been used to minimize pathogenic impacts to bivalve molluscan shellfish growing areas from treated wastewater effluent in the National Shellfish Sanitation Program (NSSP). For over twenty five years, the U.S. Food and Drug Administration (FDA) has recommended a minimum of 1000:1 dilution of effluent within prohibited closure zones established around wastewater treatment plant (WWTP) discharges. During May 2010, using recent technologies, a hydrographic dye study was conducted in conjunction with a pathogen bioaccumulation study in shellfish adjacent to a WWTP discharge in Yarmouth, ME. For the first time an improved method of the super-position principle was used to determine the buildup of dye tagged sewage effluent and steady state dilution in tidal waters. Results of the improved method of dilution analysis illustrate an economical, reliable and more accurate and manageable approach for estimating the buildup and steady state pollutant conditions in coastal and estuarine waters.

Modelagem da dispersão de coliformes termotolerantes e enterococos em duas enseadas na região costeira de Ubatuba (SP), Brasil

RESUMO Foram avaliados os efeitos de ações antrópicas sobre o sistema costeiro de Ubatuba (SP) através de modelos que descrevem os mecanismos e as reações envolvidas na dispersão de indicadores microbiológicos (coliformes termotolerantes e enterococos) na água do mar. A análise da qualidade das águas destinadas à recreação, além de ser uma ação importante em termos de saúde pública, também se justifica em vista da importância da atividade turística em Ubatuba, possuindo, ainda, grande relevância para o planejamento ambiental. Na modelagem, foram utilizados os módulos do sistema Delft3D. No módulo de qualidade da água, foram estudados os mecanismos de dispersão dos poluentes, a partir da associação de dados de poluição com os resultados do módulo hidrodinâmico, em duas enseadas em Ubatuba (SP): Flamengo e Palmas. Os resultados obtidos permitem afirmar que o sistema de correntes nas enseadas, determinado pela geomorfologia da região, não confere alta capacidade de diluição e dispersão de efluentes na área de estudo. Todavia, a circulação marinha e os processos envolvidos no decaimento das bactérias são suficientes para difundir e diminuir suas concentrações ao longo das enseadas. Concluiu-se que a modelagem ambiental reproduziu de maneira satisfatória os processos envolvidos no transporte e na difusão de indicadores microbiológicos, contribuindo com os estudos sobre os efeitos das atividades antrópicas no sistema costeiro de Ubatuba.

Cytogenotoxicity screening of source water, wastewater and treated water of drinking water treatment plants using two in vivo test systems: Allium cepa root based and Nile tilapia erythrocyte based tests

Biological effect directed in vivo tests with model organisms are useful in assessing potential health risks associated with chemical contaminations in surface waters. This study examined the applicability of two in vivo test systems viz. plant, Allium cepa root based tests and fish, Oreochromis niloticus erythrocyte based tests for screening cytogenotoxic potential of raw source water, water treatment waste (effluents) and treated water of drinking water treatment plants (DWTPs) using two DWTPs associated with a major river in Sri Lanka. Measured physico-chemical parameters of the raw water, effluents and treated water samples complied with the respective Sri Lankan standards. In the in vivo tests, raw water induced statistically significant root growth retardation, mitodepression and chromosomal abnormalities in the root meristem of the plant and micronuclei/nuclear buds evolution and genetic damage (as reflected by comet scores) in the erythrocytes of the fish compared to the aged tap water controls signifying greater genotoxicity of the source water especially in the dry period. The effluents provoked relatively high cytogenotoxic effects on both test systems but the toxicity in most cases was considerably reduced to the raw water level with the effluent dilution (1:8). In vivo tests indicated reduction of cytogenotoxic potential in the tested drinking water samples. The results support the potential applications of practically feasible in vivo biological test systems such as A. cepa root based tests and the fish erythrocyte based tests as complementary tools for screening cytogenotoxicity potential of the source water and water treatment waste reaching downstream of aquatic ecosystems and for evaluating cytogenotoxicity eliminating efficacy of the DWTPs in different seasons in view of human and ecological safety.

Phytoremediation of Secondary Effluent from Palm Oil Mill by Using Oleaginous Microalgae for Integrated Lipid Production and Pollutant Removal

To replace petroleum-based fuels, fast-growing microalgae are currently receiving attention as alternative sources of fuels. In this study, twelve microalgae strains from three genera representing oleaginous microalgae, namely Botryococcus, Scenedesmus and Chlorella, were screened. The selected strains from each genus were applied in integrated lipid production and phytoremediation of secondary effluent from palm oil mill. Among the strains tested, Chlorella sp. C-MR was the most suitable strain to be cultivated in the effluent, due to its high growth rate and high lipid productivity. The optimal conditions for lipid production were: dilution of effluent at 1:1 (COD 1266 mg/L) and light intensity of 40 μmol/m2 s. The semi-continuous cultivation of this microalga was effective for sustained lipid production (0.19–0.24 g/L) and pollutant removal, i.e., COD removal (58–65 %), nitrogen removal (71–99 %) and phosphorus removal (42–64 %). The microalgal lipids contained mainly saturated fatty acids (>85 %), which are suitable for producing biodiesel with high cetane number and oxidative stability.

Incubation experiments to determine the response of a natural plankton community to treated sewage effluent

The Orange County Sanitation District diverted flow of secondarily-treated effluent from a discharge pipe located 8.0 km offshore at 60 m depth to an outfall located 1.6 km offshore at 16 m depth for three weeks in September of 2012. Two incubation experiments were performed to examine the potential for this effluent to stimulate the growth and impact the structure of natural, coastal plankton communities. The first experiment was initiated a week prior to the diversion of effluent to the nearshore site (‘Pre-Diversion’), and the second began a week after the start of the diversion (‘Mid-Diversion’). The overall phytoplankton response observed in both experiments following effluent addition was an increase in the abundances of diatoms and photosynthetic picoeukaryotes, and a decrease in picocyanobacteria. A dramatic net increase in heterotrophic bacterial abundances also occurred in both experiments. Additions of a 1:10 dilution of effluent yielded significant increases in chlorophyll a concentrations, although this treatment in the Pre-Diversion experiment exhibited a 3 day lag in response to effluent addition, perhaps indicating that the Pre-Diversion community was inhibited by the enhanced chlorination process that was enacted during the diversion. Domoic acid producing diatoms in the genus Pseudo-nitzschia were present in the plankton throughout the experiments, but domoic acid production was only detected during the Mid-Diversion experiment. The highest concentration of domoic acid measured, 0.42 ± 0.057 μg/L, coincided with phosphate and silicate concentrations below the detection limit of the method, suggesting limitation by these macronutrients.

Treatment of textile industry effluents using orange waste: a proposal to reduce color and chemical oxygen demand

Various agricultural residues have been tested as biosorbents due to their low cost, high surface area, and favorable surface chemistry. In this work, a sweet orange albedo was tested as a biosorbent for treatment of real textile effluents. The orange albedo powder was prepared by drying the residue at 50 °C and milling to 30 mesh, and then used for dye adsorption from a alkaline (pH = 10.71) effluent. The adsorption process was studied in batch experiments at 30 °C by measuring color removal and chemical oxygen demand (COD). The color removal was found not to be significantly altered when the effluent was used in its raw state, while COD increased probably due to albedo degradation. For the effluent diluted to 60% (Veffluent VH2O(-1)), color and COD removal percentages of approximately 89% were obtained. It was found that pH played a very significant role on the adsorption process, as the treated albedo displayed a relative pHPZC* of 4.61, and the highest dye removal efficiencies were reached at pH lower than 2. The COD was strongly influenced by the effluent dilution. The effectiveness in eliminating color and COD shows that orange albedo can be potentially used as a biosorbent to treat textile wastewater.

Effects of exposure to zinc oxide nanoparticles in freshwater mussels in the presence of municipal effluents

Zinc oxide (nano-ZnO) nanoparticles are used in the production of transparent sunscreens and cosmetics, which are released into surface waters and municipal wastewater effluent. The purpose of this study was to examine the toxicity of nano-ZnO in the presence of municipal effluents to freshwater mussels Elliptio complanata. Mussels were exposed for 21 days at 15 o C to nano-ZnO and ZnCl2 in the presence of 10 % dilution of primary-treated municipal effluent. After the exposure period and 24-h depuration step, mussels were analyzed for total Zn in gills and digestive gland, free Zn, metallothioneins (MT), oxidative stress (glutathione S-transferase and LPO), endoplasmic reticulum stress (heat shock proteins and protein ubiquitination) and genotoxicity. The data revealed that although total Zn loadings did not change with these treatments, Zn levels in digestive gland were elevated in mussels exposed to nano-ZnO but not with ZnCl2 in the presence of municipal effluent. Free Zn levels in the gills were elevated in mussels exposed to the municipal effluent, but decreased in mussels exposed to nano-ZnO. MT in digestive gland showed a similar pattern and was negatively associated with free and total Zn. GST activity was significantly reduced by both nano-ZnO and municipal effluent and was negatively correlated with MT levels, suggesting the involvement of MT in the sequestration of reactive oxygen species. Discriminant function analysis showed that the municipal effluent related effects differed from the unexposed mussels and nano-ZnO exposed mussels in terms of the following responses: free Zn in gills and digestive gland and GST activity. Nano-ZnO related effects also involved GST activity, MT and protein ubiquitination, which suggests a combination of oxidative stress and reticulum endoplasmic stress. In respect with oxidative stress, the oxidative properties of nano-ZnO and ZnCl2 are dampened in the presence of the municipal effluent.

Computational study of mass and heat transport in a counterflowing turbulent round jet

This paper investigates the aspect of a hydraulic round jet issuing into a uniform counterflow under a range of jet-to-current velocity ratios. The prediction of the centerline dilution of jet effluent at velocity ratios ranging from 3 to 15 is performed using the Reynolds Stress Model (RSM). The penetration length is determined by considering the 5% contour of the centerline concentration and compared with empirical relationships suggested by previous researches. A similarity analysis is conducted on the radial profiles of both mean concentration and temperature at successive streamwise stations. The heat transport between the jet fluid and the opposed stream is also investigated with emphasis on the temperature effect on characteristics of the concentration field.

Numerical Simulation of a Round Buoyant Jet in a Counterflow

Discharge of pollutants into the receiving water bodies is generally in the form of a turbulent jet or plume, the presence of a counterflow enhances the initial dilution of the jet effluent. To obtain better understanding of jet behaviors in a realistic situation, a round buoyant jet issuing horizontally into a uniform counterflow is simulated at different combinations of densimetric Froude number (F) and jet-to-current velocity ratio (R). A two-phase mixture model simulates this flow and the renormalization group (RNG) k-ɛ model to solve flow turbulence. The inter-phase interactions are described in terms of relative slip velocity between phases. The numerical results of concentration field are in good agreement with W.Y.Lee's experimental observation. The jet features including trajectory of the jet centerline and the decay of centerline concentration are studied. Through the comparison of all cases, this paper also analysis the effect of buoyancy and velocity ratio on jet behaviors. Based on length scale analysis, the article gives the corresponding relationships between the distance and the centerline dilutions. The results indicate that the flow mechanisms before and after the penetration point are quite different.

Evaluation of WET Testing as an Indicator of Aquatic Health

This project evaluated the quality of data needed to determine relationships between chronic Whole Effluent Toxicity (WET) test results and instream biological condition. A data quality objectives approach was used, which included several proposed measurement quality objectives (MQOs) that specified desired precision, bias, and sensitivity of methods used. Six facilities (four eastern and two western U.S.) participated in this study, all having design effluent concentrations > 60% of the stream flow. In accordance with a Quality Assurance Project Plan most of the facilities completed four quarters of chronic Ceriodaphnia dubia, and Pimephales promelas (fathead minnow) WET tests, and three quarters of Selenastrum capricornutum (green algae) WET testing following the most recent USEPA methods. Several other WET tests were conducted to address MQOs including splits, duplicates, and blind positive and negative controls. Macroinvertebrate, fish, and periphyton bioassessments were conducted at multiple locations up and downstream of each facility following the most recent USEPA Office of Water bioassessment protocols. Test acceptance criteria were met for most WET tests, however, this study demonstrated the need to incorporate other MQOs in a full study (such as minimum and maximum percent significant differences and performance on blind samples) to ensure accurate interpretation of effluent toxicity. More false positives, lower test endpoint (i.e., higher toxicity), and more “failed” (non-compliant) tests were observed using No Observed Effect Concentrations (NOEC) as compared to IC25s (concentration causing = 25% decrease in organism response compared to controls). Algae tests often yielded the most effluent toxicity in this study, however, this test was most susceptible to false positives and high inter-laboratory variability. WET test results exhibited few relationships with bioassessment results, even when incorporating actual effluent dilution. Neither frequency of WET non-compliance nor magnitude of WET were clearly related to differences in biological condition up and downstream of a discharge for the most part. Macroinvertebrate assessments were most able to discriminate small changes downstream of the effluent, followed by periphyton and then fish. The sampling methods used were robust but a full study should collect more field replicates up and downstream of each discharge to increase detection power. Macroinvertebrate and periphyton assessments together appeared to be sufficient to address project objectives. Fish assessments could be useful as well but would entail more effort and cost per site than expended in this project to be useful. This title belongs to WERF Research Report Series ISBN: 9781843397687 (Print) ISBN: 9781780403793 (eBook)

Cultivation of Arthrospira (Spirulina) platensis using confectionary wastes for aquaculture feeding.

The microalga biomass production from confectionary effluent is a possible solution for the urgent need for a live food in aquaculture. Arthrospira (Spirulina) platensis was the dominant alga in effluent of “Biscomisr a confectionary factory”, in Alexandria–Egypt. Therefore, it was isolated from the effluent samples and used throughout the study. The cyanobacterium, A. platensis was grown on the effluent using 22 Central Composite Design (22 CCD). This work addresses the best effluent dilution (WC, %) as well as sodium bicarbonate concentration (SBC) on the alga growth and biochemical composition. Total protein, carbohydrate, lipid contents and fatty acid profiles of the produced algal biomass were highly improved. The statistical analyses suggested that the main effect of (WC, %) is significant negative influences on the algal contents of proteins, lipids and carbohydrates (p > 0.01). Although it had a significant positive influence on chlorophyll (p > 0.01), no significant effect on algal β carotenes (p > 0.05) had been reported. The inter action effect of SBC together with WC, % exerted a significant negative influence on the algal proteins (p > 0.01) and no significant effect on the other responses (p > 0.05). The produced alga biomass was used for feeding the rotifer, Brachionus plicatilis for further application in aquaculture. Growth rate, reproductive rate and fecundity attributes, fatty acid content of B. plicatilis were amended. The Pearson correlation test indicated that β carotenes displayed a highly positive significant correlation with the growth rate of B. plicatilis (r = 0.733, p < 0.01) and the carbohydrates showed significant positive correlations with Egg % (r = 0.657, p < 0.05).