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Abstract This study highlights the importance of managing fishpond effluent to minimize its impact on aquatic environments. Fish effluents are a major concern worldwide in aquatic environments. It also provides information on the impacts of effluents on the water quality index of streams when released into aquatic environments. Streams and fishponds were sampled bimonthly for two annual cycles, covering different sampling stations both upstream and downstream of the fishpond effluents at 50-m intervals. Water quality parameters associated with in situ conditions were determined in the field. In the laboratory, other physicochemical parameters were determined via proper standard protocols. The results of the study revealed that water quality parameters such as turbidity, total suspended solids, total solids, conductivity, total dissolved solids, dissolved oxygen, biological oxygen demand and organic matter recorded in water samples collected from 50 m upstream at the point of effluent discharge were significantly (p

This study assessed the quality status of the Eruvbi River in Benin City, Nigeria using the National Sanitation Foundation Water Quality Index (NSFWQI). The physicochemical and microbiological parameters analysed were pH, temperature, turbidity, total dissolved solids (TDS), phosphate, nitrate, biochemical oxygen demand (BOD), dissolved oxygen (DO), and total coliforms. All parameters were analysed using standard methods. For each parameter, the temporal and spatial range were pH (5.3 - 6.2), temperature (22.0 - 28.0 oC), turbidity (5.0 – 128.0 NTU), TDS (20.0 – 128.0 mg/L), phosphate (0.1 – 1.0 mg/L), nitrate (0.2 - 0.8 mg/L), BOD (3.4 - 6.2 mg/L), DO (5.0 - 11.2 mg/L), while the mean for total coliform count ranged from (416.9 - 295120.5 CFU/100 mL). The results were compared against national and international standards with the temperature, TDS, and nitrate values within set limits, while the non-conforming parameters were majorly total coliform, phosphate, turbidity, and pH. The overall NSFWQI results indicated moderate water quality, with WQI values ranging from 54.04 to 61.95 at all sampling locations. The middle stream had the lowest NSFWQI value caused by effluent discharge from a carbonated drink industry. The moderate water quality means that additional treatment is required before the water can be considered safe for drinking and domestic purposes. The NSFWQI protocol makes it easier to explain the water quality to the general public and decision-makers, and it can be a valuable tool for water management.

Due to the difference in density between the discharge effluent and coastal water, partially treated wastewater is often discharged into the marine environment as a buoyant jet via submarine outfalls with multiport diffusers. The dilution characteristics of effluent discharge (dual buoyant jets) in a wavy cross-flow environment were studied in a laboratory. The planar laser-induced fluorescence technique was used to obtain the concentration data of the jets. The effects of different environmental variables on the diffusion and dilution characteristics of the jets were examined through physical experiments, dimensional analysis, and empirical formulations. It was found that the dilution process of the dual jets could be divided into two components: the original jet component and the effluent cloud component. The jet-to-current velocity ratio was the main parameter affecting the concentration levels of the effluent cloud. The merging of the two jets increased the jet concentration in the flow field. When the jets traveled further downstream, the axial dilution increased gradually and then increased significantly along the axis. Under the effects of strong waves, the concentration contours branched into two peaks, and the mean dilution became more significant than under the effects of weak waves. Therefore, the dilution of the effluent discharge was expected to be significant under strong wave effects because the hydrodynamic force increased. A dilution equation was derived to improve our understanding of the dilution process of buoyant jets in a wavy cross-flow environment. This equation was used to determine the influences of the jet-to-current velocity ratio, wave-to-current velocity ratio, and Strouhal number on the minimum jet dilution. It revealed that the wave and buoyancy effects in effluent discharges were significant.

Assessment of groundwater resource around an abattoir site in Igoba area of Ondo State, southwestern Nigeria has been carried out, within 1.3 km radius from the abattoir site in order to determine the influence of the effluents discharge on quality of groundwater in the area, so as to forestall outbreak of diseases that can endanger human health. Eleven water samples were analyzed for physical, chemical and microbial parameters; and result subjected to spatial and statistical analysis using analysis of variance and Duncan’s multiple range of variance. The obtained parameters mean ± SD are pH (5.5±0.50), turbidity (10±5.9 NTU), temperature (27.75±0.35 °C), conductivity (240±105.99µs/cm), total dissolved solid (158.9±46.8 mg/L), total hardness (92.1±14.2 mg/L), nitrate (7.3±4.3 mg/L), iron (0.24±0.04 mg/L), total alkalinity (14.57±4.87 mg/L), manganese (0.017±0.0079 mg/L), calcium (26.53±8.7 mg/L), magnesium (12.20±8.1 mg/L), chloride (21.86±7.39 mg/L), sodium (14.71±4.85 mg/L), bicarbonate (13.95±4.48 mg/L), nitrite (0.0336±0.0269 mg/L), dissolved oxygen (1.82±0.52 mg/L), chemical oxygen demand (133.1±53.7 mg/L), biological oxygen demand (29.55±10.93 mg/L), total coliform (9.36±6.05 cfu/100ml) and E.coli (0.5090±0.4700 cfu/100ml). The analysis of variance showed that statistically significant difference occurs among the parameters (p

An experiment was conducted in a permeability tank constructed at the Laboratory of Department of Land and Water Management. Two soils with different textures collected from Khesana Mori and Nasarpur were used in the experiment. Soils were analyzed for the textural class and hydraulic conductivity. The soil collected from Khesana mori was sandy with hydraulic conductivity of 6.9 m/day, while the soil brought from Nasarpur was clay loam with hydraulic conductivity of 0.0564 m/day. Three impervious layers were imposed at 100, 200, and 300mm depths and four water table depths were maintained from soil surface at 0.0, 30.0, 60.0, 90.0 mm depths above the lateral. The effluent discharge was measured by volumetric method and same was calculated using Hooghoudt’s formula. The results showed that the effluent discharge from laterals was maximum when the water table depth was maintained at soil surface under both sandy and clay loam soils. The effluent discharge decreased with the increase in the depth of impervious layer. Hydraulic head above the lateral influenced the effluent discharge. When the hydraulic head increased the effluent discharge also increased. The study also found that the sandy soil with higher value of hydraulic conductivity collected from Kesana Mori had more effluent discharge compared to that of clay loam soil with lower value of hydraulic conductivity collected from Nasarpur. Therefore the drain spacing must be decided on the basis of water table depth, location of impervious layer, soil texture and hydraulic conductivity.

Liquid Natural Gas (LNG) processing facilities typically are located on ocean shores for easy transport of LNG by marine vessels. These plants use large quantities of water for various process streams. The combined wastewater effluents from the LNG plants are discharged to the coastal and marine environments typically through submarine outfalls. Proper disposal of effluents from an LNG plant is essential to retain local and regional environmental values and to ensure regulatory and permit compliance for industrial effluents. Typical outfall designs involve multi-port diffuser systems where the design forms a part of the overall environmental impact assessment for the plant. The design approach needs to ensure that both near-field plume dispersion and far-field effluent circulation meets the specified mixing zone criteria. This paper describes typical wastewater process streams from an LNG plant and presents a diffuser system design case study (for an undisclosed project location) in a meso-tidal coast to meet the effluent mixing zone criteria. The outfall is located in a coastal and marine ecosystem where the large tidal range and persistent surface wind govern conditions for the diffuser design. Physical environmental attributes and permit compliance criteria are discussed in a generic format. The paper describes the design approach, conceptualization of numerical model schemes for near- and far-field effluent mixing zones, and the selected diffuser design.

Since the introduction of the water footprint concept in 2002, in the context of humankind’s ever-increasing awareness of the valuable global freshwater resources, it has received more and more attention. The application of this relatively new concept has been expected to provide ecological and environmental benefits. For the water-intensive papermaking industry, it seems that water footprint needs to be addressed. The water footprint of cellulosic paper can be divided into three components, including its green water footprint, blue water footprint, and grey water footprint, which may be accounted for by considering the individual contributions of wood or non-wood materials, pulp production processes, effluent discharge to the receiving water bodies, process chemicals and additives, energy consumption, etc. In the literature, the accounting of water footprint during the whole production chain of cellulosic paper is already available, and relevant research findings can provide useful insights into the application of the concept; however, further development of the accounting methodologies is much needed, so that the quantitative and qualitative evaluation of water footprint can be internationally recognized, certified, and standardized. Although there are ongoing or upcoming debates and challenges associated with the concept, its application to papermaking industry may be expected to provide various encouraging possibilities and impacts.