Effluent waste generated from the intensive production of vannamei shrimp is known to play an essential role in increasing phytoplankton abundance and the alteration of environmental quality. This alteration is characterized by the presence of various organic compounds and their derivatives. The northern coastal area of Bangka Island represents a region in Indonesia that has witnessed significant growth and development as a vannamei shrimp cultivation zone. Therefore, this study aims to evaluate phytoplankton abundance and environmental quality in the waste of shrimp ponds in the northern coastal area of Bangka Island. The investigation procedures were carried out in four specific locations within this area, namely BL1, BL2, BL3, and BL4. The results showed the presence of five–six distinct phytoplankton groups, including a total of 11–18 genera, within the effluent discharge from these ponds. The highest abundance of phytoplankton was recorded at BL3, with a value of 2,418,375 cells ml−1. The phytoplankton groups identified at all locations included Chlorophyta, Cyanophyta, Chryptophyta, Bacillariophyta, and Pyrrophyta. Euglenophyta was found at BL1 and BL3 but was not observed at BL2 and BL4. Furthermore, the most abundant group found in this study was Chlorophyta. The genera Nanochloropsis, Chlorella, Microcystis, and Nitzschia were consistently found in all the surveyed ponds. The calculation results showed that all locations had a moderate level of diversity, high evenness, and the absence of dominance. Based on the findings of principal component analysis, there was a commonality in parameters that exerted a strong influence on phytoplankton abundance, including nitrate, orthophosphate, and magnesium.

The ability of Na-activated bentonite to remove Ni2+ and Co2+ from aqueous solutions at room temperature (22 ± 1°C) was studied under various experimental conditions. The parameters studied were solid-to-liquid ratios and initial cation concentrations. Experiments involved the behavior of bentonite vs. Ni and Co separately and where Ni and Co were present in solution at different concentrations and ratios. Bentonite retained substantial amounts of both metals readily, but it showed a higher affinity for Ni. Over-exchange appears when initial metal concentration exceeds the concentration corresponding to the cation exchange capacity (CEC) of bentonite. The presence of both metals in solution may be either synergistic or antagonistic sorption, depending on the initial ion concentrations.

The removal of Co2+, Ni2+, and Pb2+ from aqueous solutions using a modified zeolite was investigated because of the need to eliminate toxic contaminants from wastewaters. In the present study the ways in which equilibrium, thermodynamics, and kinetics parameters affected the removal of heavy metals were evaluated and compared. An Iranian clinoptilolite with a Si/Al ratio of 6.5 was used as an adsorbent. In order to increase the adsorption capacity of the adsorbent, it was converted to a manganese oxide-coated zeolite (MOCZeo) using various Mn solutions. The initial concentration of metals, pH, contact time, and temperature were the variables studied and optimal conditions were established. The maximum amount of Co2+, Ni2+, AND Pb2+ adsorption on MOCZeo was ascertained. A thermodynamics study, using ΔG, ΔH, and ΔS state functions showed that adsorption of Pb2+ was more spontaneous than that of Co2+, Ni2+ ions. The adsorption of these ions on MOCZeo was an endothermic reaction. Investigation of the adsorption models revealed that the adsorption of Pb2+, Co2+, and Ni2+ on MOCZeo followed both the Langmuir and Freundlich models. Kinetics studies showed that the adsorption of Pb2+, Co2+, and Ni2+ on MOCZeo followed the pseudo-second order kinetics model with a high correlation coefficient.

The worldwide use of pharmaceuticals is of concern to those researchers who develop new techniques for the removal of these compounds from the aquatic medium. The objective of the present work was to characterize and evaluate the performance of a commercial, bentonite-based organophilic clay in removing ivermectin from aqueous solution. The adsorbent was characterized by nitrogen physisorption, thermogravimetric-differential scanning calorimetry (TG-DSC), X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR). Batch-scale adsorption experiments were performed to evaluate the kinetics, isotherms, thermodynamics and effect of pH on removal of this drug and reuse of the clay. The bentonite has a small specific surface area with an irregular surface. The Elovich kinetic model fits the experimental data better than other models, indicating that chemisorption contributes to drug removal in this case. The Langmuir and Sips isothermal models best fit the experimental equilibrium data. The process was shown to be favorable (ΔG°ads<0), endothermic (ΔH°ads>0), with an increase in the degrees of freedom at the solid–liquid interface (ΔS°ads>0), and with characteristics of a physical-chemical adsorption process (Ea = 11.065 kJ mol–1) under the study conditions. Adsorption was favored at the natural pH of the solution and the organophilic clay could be regenerated with water and reused in consecutive adsorption cycles. The amount of ivermectin adsorbed on the organophilic clay ranged from 1.78 to 3.88 mg g–1. The organophilic clay was shown to be a cost-effective potential adsorbent for ivermectin-contaminated water-treatment applications.

The influence of nutrient loading and other anthropogenic stressors is thought to be greater in low inflow, microtidal estuaries, where there is limited water exchange. This 11-month study compared spatial changes in macrofaunal communities adjacent to regions that varied in land cover in Oso Bay, Texas, an estuarine secondary bay with inflow dominated by hypersaline discharge, in addition to discharge from multiple municipal wastewater treatment plants. Macrofauna communities changed in composition with distance away from a wastewater treatment plant in Oso Bay, with the western region of the bay containing different communities than the head and the inlet of the bay. Ostracods were numerically dominant close to the wastewater discharge point. Macrobenthic community composition is most highly correlated with silicate concentrations in the water column. Silicate is negatively correlated with salinity and dissolved oxygen, and positively correlated with nutrients within the bay. Results are relevant for environmental management purposes by demonstrating that point-source discharges can still have ecological effects in hydrologically altered estuaries.

Many developing countries lack universal sanitation services for residents. Years of inappropriate disposal of solid waste and wastewater have increased the potential for devastating environmental and health issues. An economic valuation of sanitation services may help in planning investment projects by demonstrating the benefits that households derive from having access to improved sanitation. We examine Guatemala as a case study and employ a series of hedonic models to estimate the value that households in Guatemala assign to the sanitation services of solid waste collection and connections to sewer infrastructure. Findings indicate that residents are willing to pay higher rents for both wastewater and solid waste removal. Policy implications are discussed.

Tianjin is the largest port city in Northern China and a major hub for water and land transportation. For geological reasons, the city has long been troubled by water drainage problems. To remove wastewater from within its walls, the city developed a drain system which relies on human labor and a series of variously sized ditches. Unlike the modern sewage system, which simply discharges wastewater into surrounding rivers and the sea, Tianjin's traditional wastewater disposal system worked in concert with an urban manure collection system. Urban wastewater was recycled as fertilizer, a valuable resource for the surrounding rural area. In tracing the origin, evolution, and influence of urban wastewater disposal in Tianjin, this article aims to reveal the potential value in Chinese traditional waste management practices. Contemporary urban waste disposal systems might benefit from a better understanding of the relationship between urban and rural areas that characterized these traditional practices.

Three samples of terra rossa were shown to be efficient adsorbents of phosphate [P(V)] from wastewater and removed 29.9–32.6% of P(V). The total iron content in terra rossa was the key factor which determined the P(V) removal from wastewater. The original samples of terra rossa were effective support materials for the immobilization of metabolically active P(V)-accumulating bacteria Acinetobacter junii (0.56–2.47×1010 CFU g–1). The removal of oxalate-extractable iron from original sample of terra rossa increased the number of immobilized bacteria to 1.34×10–11 CFU g–1, which is the largest number of immobilized bacteria reported in the literature so far. In reactors containing the A. junii and terra rossa P(V) was removed from wastewater by simultaneous adsorption onto terra rossa and accumulation inside bacterial cells, resulting in 40.5–62.5% of P(V) removal. Terra rossa is a promising substrate for biological P(V) removal from wastewater, acting both as adsorbent of P(V) and carrier of P(V)-accumulating bacteria.

The removal of phosphorus from wastewaters is becoming very common, to meet water quality targets, and avoid environmental problems related to eutrophication. At the same time, agricultural application of P-rich sewage biosolids is diminishing for reasons of logistics and of public pressure. As a result P from wastewaters is ultimately disposed of in landfills. Over the long term, phosphate ore reserves will become depleted. Recycling of P from wastewaters may thus be a realistic prospect if scientific and technical issues can be resolved. At the centre of the scientific problems lie considerations about optimizing phosphate precipitation as Ca phosphates. A number of Ca phosphate minerals exist, although by far the most common of these is hydroxylapatite. Precipitation kinetic considerations, however, suggest that other Ca phosphates (such as brushite, octacalcium phosphate, whitlockite, monetite or amorphous Ca phosphate) may initially precipitate, and later recrystallize into the most stable hydroxylapatite. This article reviews the complex precipitation mineralogy, chemistry and kinetics of Ca phosphates.

The contamination of water bodies in urban areas is a serious problem, which may increase when wastewater is discharged without complete remediation. Due to their high adsorption capacity and ion-exchange properties, zeolites, such as clinoptilolite, can be used successfully to detoxify the wastewater before discharging it into the water body. In this study, experimental use of clinoptilolite is presented for water remediation. A static flow (A) and a laminar flow (B) method were applied in order to evaluate the efficiency of clinoptilolite for reducing different contaminants in the outflow wastewater of an old municipal treatment plant in Bologna District (Northern Italy). Mesocosm experiments were performed in order to achieve reduction of the microbial faecal indicators and of the excess nutrients and heavy metals in the effluent. During the experiments, pathogenic microorganisms, ammonium and heavy metals were reduced by as much as between 78 and 95% within 24 h, highlighting the great efficiency of this low-cost material for water remediation.