Effectiveness of macroalgae was investigated for enhancing wastewater treatment processes. Bioremediation using macroalgae could remove nitrate and phosphate contaminants in the water where algae assimilate nitrogen and phosphorus and convert them to biomass. This study evaluates the effects of high nitrate concentration on the kinetics of cell growth during nitrate and phosphate removal by a macroalga Cladophora glomerata. The algal growth and nitrate removal from media containing initial nitrate concentrations of 5mg/L to 400 mg/L were monitored in batch growth, whereas control media has no additional nitrate. Light exposure was kept for 12 and 20 hours. The purpose of this research was to find out the effect of various nitrate concentrations on nitrate and phosphate removal with macroalgal growth. Maximum growth kinetic reaches ?=0.075/day in 20 hours light exposure with 100 mg/L initial nitrate concentration. Nitrate and phosphate reach about 90% removal rates on the fifth day. Nitrate concentration was not significantly affected by biomass growth (Pearson correlation: 0.295). But, phosphate concentration has a moderate correlation with macroalgae biomass (Pearson correlation: 0.533).

The status quo that the shortage of water resources in North China and the arbitrary discharge of sewage in rural areas have led to the deterioration of water environment, which not only aggravates the contradiction between supply and demand of regional water resources but also brings harm to people’s life and health. How to properly discharge sewage according to the actual situation in rural areas is a question that needs to be answered urgently. The method adopted in this paper is to build a constructed wetland with low cost and simple operation and maintenance in the study area, and purify the water quality through parallel + multi-stage cascade surface flow constructed wetland system. The results show that the purification effect of the wetland system is acceptable, and the removal rate of each index shows a decreasing trend with time. The larger the area is, and the more plant species there are, the better the removal effect will be. The trend of concentration change along the water flow path of each index is also gradually decreasing, and the decline in the early stage is larger. The method of standard index evaluation is adopted to evaluate water quality purification effect of the wetland system, and all indexes reach the standard. In accordance with the Surface Water Environment Quality Standard (GB3838-2002), after wetland purification, the water quality indexes of COD, TP, NH3-N and DO all reach Class IV water quality standard, and BOD5 reaches Class II water quality standard. The wetland system effectively reduces the impact of arbitrary sewage discharge on the water environment in rural areas and achieved water quality purification and ecological restoration. The quality of the living environment of local residents is improved. The beautiful environment also promotes people’s awareness of protecting wetland ecological environment.

In areas with water resources shortage, sewage irrigation can alleviate the contradiction between supply and demand for water. However, long-term use of sewage irrigation will affect soil, crops and groundwater. In this paper, irrigation water and groundwater in different irrigation source areas were sampled and analysed respectively to study the effect of sewage irrigation on groundwater. The irrigation water was evaluated for Cl-, Cd, Pb, Cr6+, As, Cu, F-, TP, Hg and Zn as standards for irrigation water quality which along with Nemerow index method were used for comprehensive evaluation. The result of the evaluation is that the water quality of the reclaimed water, domestic sewage and mixed sewage meet the requirements of the agricultural irrigation, and the industrial sewage pollution index is relatively high and less suitable for agricultural irrigation. The fuzzy comprehensive evaluation method was adopted to evaluate groundwater quality, using Quality Standard for Ground Water (GBT14848- 2017) as evaluation factor standard and ammonia nitrogen (NH3-N), chloride (Cl-), nitrate (NO3-N) and nitrite (NO2-N) as evaluation indicators. The results of the evaluation showed that the water quality of 2 monitor wells among the 11 monitor wells was within Category II, 6 within Category III, and 3 within Category IV. With regards to the influence of different irrigation sources on groundwater, the comprehensive evaluation results are reasonable as well. According to the comprehensive membership grades, it can be concluded that the influence of different water sources on groundwater quality, in turn, is reclaimed water < domestic sewage < mixed sewage < industrial sewage. The evaluation results are in line with the actual situation in the study area.

Jiagou district, located in Northern Anhui Province, China, has been taken as an agriculture demonstration base for several decades, but limited hydrochemical work has been conducted on the water resources. The objective of this research was to understand the controlling processes of hydrochemical evolution and the water quality for drinking and irrigation. Twenty-seven samples of surface water and groundwater have been collected and analysed for major ions. Although the values physicochemical parameters are subjected of spatial fluctuation in different water resources, calcium and bicarbonate is still the dominant ion in the cations and anions, respectively. The values of all the parameters are within the WHO maximum permissible limit for inhabitant drinking. The predominant water type is Ca-Mg-HCO3 and Ca-HCO3. The hydrochemical methods (Gibbs diagram, Mg/Na and HCO3/Na versus Ca/Na diagram and ion ratios) suggest that rock-water interactions furnish the dominant major ion sources of the samples. Carbonate dissolution, silicate weathering and ion exchange have the predominant contribution to the origin of chemical solutes, as well as a slight function of halite dissolution. The USSL and Wilcox diagram reveal that all the samples have low salinity and low sodium water. It is of good quality suitable for irrigation, and it can be used for irrigation of most crops on most soils with less negative impacts.

Biochar was prepared from the peanut shell. Then, it was mixed with the clay mineral kaolinite and stirred under the magnetic stirrer. The biochar derived from peanut shell supported with clay mineral kaolinite (B@K) was obtained. Adsorption experiments of dye Acid Orange 7 by B@K were conducted. The characteristics of B@K were determined by the elemental analyzer, specific surface area meter, scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectrometer and the model axis-HS. The experimental results showed that a large number of oxygen-containing functional groups appear on the surface of B@K, which is beneficial for binding dye ions. The adsorption process fits well with the pseudo-second-order kinetic model. It indicated that the adsorption process was both physical adsorption and chemical adsorption. Chemical adsorption is the main adsorption process. Langmuir isotherm model can better describe the adsorption isothermal process of B@K on dye Acid Orange 7. The adsorption process is monolayer adsorption process.

Use of cyanide in developing countries is rampant, especially in gold mining areas. Though it could cause serious environmental problems, cyanide contamination is of less priority for government monitoring because of the limited resources. The current detection and monitoring schemes of cyanide are the conventional and expensive laboratory-based methods, which need technical capabilities to conduct the actual testing and preparing manual data recording, making it tedious and too laborious. More efforts were directed towards digitizing the data recording from manual laboratory analyses as the manual data recording usually cause problems like delayed information, lost data, and erroneous data entry. Hence, the goal of this study is to provide a cost-effective and zero manual-recording measurement method for cyanide in water samples. This work focuses on the design of electrochemical measuring devices with the same capability with the portable or benchtop-type of cyanide meter but with an automated and realtime data recording using global system for mobile communications (GSM) technology. Results of this study showed that with the existing GSM technology and infrastructure of the new monitoring system, the measurements are comparable to that of a commercial bench-type cyanide meter with an R-squared (R2) of 0.9907. It was also noted that data being recorded were intact during wireless transmission testing using the GSM Network. The results obtained suggest that wireless communication using GSM Technology could be applied to environmental monitoring. Importantly, the newly developed online system for cyanide monitoring offers significant advantages over the conventional techniques such as low-cost, easy deployment, and ease of use. It can increase spatiotemporal data for better analysis of the data. The automated data acquisition and display through cellular phones are also made readily-available.

Neurodegenerative disorders are typically sporadic in nature in addition to usually influenced through an extensive range of environmental factors, lifestyle, and genetic elements. Latest observations have hypothesized that exposure of environmental factors may increase the prospective risk of Alzheimer’s diseases (AD). However, the role of environmental factors as a possible dangerous issue has extended importance concerned in AD pathology, although actual etiology of the disorder is still not yet clear. Thus, the aim of this review is to highlight the possible correlation between environmental factors and AD, based on the present literature view. Environmental risk factors might play an important role in decelerating or accelerating AD progression. Among well-known environmental risk factors, prolonged exposure to several heavy metals, for example, aluminum, arsenic, cadmium, lead, and mercury; particulate air, and some pesticides as well as metal-containing nanoparticles have been participated to cause AD. These heavy metals have the capacity to enhance amyloid β (Aβ) peptide along with tau phosphorylation, initiating amyloid/senile plaques, as well as neurofibrillary tangle formation; therefore, neuronal cell death has been observed. Furthermore, particulate air, pesticides, and heavy metal exposure have been recommended to lead AD susceptibility and phenotypic diversity though epigenetic mechanisms. Therefore, this review deliberates recent findings detailing the mechanisms for a better understanding the relationship between AD and environmental risk factors along with their mechanisms of action on the brain functions.

The circular economy concept boosts the use of wastes as secondary raw materials in the EU renewable and sustainable framework. In wastewater treatment plants (WWTP), sludge is one of the most important wastes, and its management is being widely discussed in the last years. In this work, sewage sludge from WWTP was employed as raw material for producing activated carbon (AC) by physical-chemical activation. The prepared AC was subsequently tested for hydrogen sulphide removal in view of its further use in deodorization in a WWTP. The effects of the activation temperature and the chemical agent used (NaOH and KOH) during the activation process were studied. On the one hand, the characteristics of each AC fabricated were analysed in terms of BET (Brunauer-Emmett-Teller) surface area, pore and micropore volume, pore diameter, surface morphology and zeta potential. On the other hand, BET isotherms were also calculated. Finally, both the prepared AC and a commercial AC were tested for H₂S removal from a gas stream. Results demonstrated that the optimum physical and chemical activation temperature was 600 °C and 1000 °C, respectively, and the best activated agent tested was KOH. The prepared AC showed excellent properties (specific surface area around 300 m²/g) for H₂S removal, even better efficiencies than those achieved by the tested commercial AC.

An outdoor pot experiment was conducted to study the control effects of zero-valent iron (Fe⁰) on arsenic (As) uptake by rice (Oryza sativa L.) and its relationship with iron (Fe), As, and phosphorus (P) in soil and Fe plaque. The results showed that Fe⁰ reduced total and inorganic As in root, husk, and grain but had no significant effect in straw, and almost all contents of As species in rice plant were decreased by Fe⁰. Total As contents in root, husk, and grain were decreased (54.8%, 39.9%, 30.1%), while reductions of inorganic As were 59.2%, 30.8%, and 30.3%, respectively. The inorganic As in all issues of rice plant was dominated and higher than 70% of total As. The analysis showed that the main mechanisms of Fe⁰ on reduction of As in rice were (i) Fe⁰ stabilized the active As in soil, (ii) Fe⁰ increased the quantity of Fe plaque that hindered the transport of arsenic in soil to rice plant, and (iii) phosphorus adsorbed on the Fe plaque reduced As into rice root by the competitive mechanism between phosphorus and arsenic. Graphical abstract

Narrabeen Lagoon is recognized as an Intermittently Closed and Open Lake or Lagoon (ICOLL) and is the largest coastal lagoon (2.2 km²) in the Sydney metropolitan region. The catchment (53 km²) supports five major river systems, and land use comprises of 56% residential, 42% parkland and 2% light industry, commercial, hospital and education. An initial screening environmental assessment was undertaken using sedimentary metals to determine the magnitude of anthropogenic change and level of ecological risk posed by these contaminants. Results illustrated an unusual example of an estuary significantly influenced by human-induced change, but exhibiting minimal ecological risk. This anomaly was due to high anthropogenic metal concentrations in the fine fraction of surficial sediment, which was considerably diluted by abundant metal-poor coarse material resulting in reduced adverse ecological impact for total sediment. Predictive modelling to 2020 suggested that Pb concentrations will decline and Cu and Zn levels will increase slightly. Modelling of river discharge and analyses of fluvial sedimentary metals suggested stormwater derived from the most urbanized catchments and a major roadway combined with poor flushing explained surficial sediment metal distributions in the lagoon.