Monitoring the effects of wastewater treatment strategies

Toward sustainability and resilience in Chilean cities: Lessons and recommendations for air, water, and soil issues

Achieving sustainability and resilience depends on the conciliation of environmental, social, and economic issues integrated into a long-term perspective to ensure communities flourish. Many nations are transitioning toward both objectives, while at the same time addressing structural concerns that have not allowed them to look after the environment in the past. Chile is one of these nations dealing with such challenges within a particular administrative context, an increasing environmental awareness, and a set of unique and complex geophysical boundaries that impose a plethora of hazards for cities, ecosystems, and human health. This paper presents recent accomplishments and gaps, mostly from an environmental perspective, on issues related to air pollution, the urban water cycle, and soil contamination, in the path being followed by Chile toward urban sustainability and resilience. The focus is on the bonds between cities and their geophysical context, as well as the relationships between environmental issues, the built environment, and public health. The description and diagnosis are illustrated using two cities as case studies, Temuco and Copiapó, whose socioeconomic, geographical, and environmental attributes differ considerably. Particulate matter pollution produced by the residential sector, drinking water availability, wastewater treatment, stormwater management, and soil contamination from the mining industry are discussed for these cities. Overall, the case studies highlight how tackling these issues requires coordinated actions in multiple areas, including regulatory, information, and financial incentive measures. Finally, the policy analysis discusses frameworks and opportunities for Chilean cities, which may be of interest when conceiving transitional paths toward sustainability and resilience for other cities elsewhere.

Microbial Electrochemical Technologies for Sustainable Nitrogen Removal in Marine and Coastal Environments

For many years, the world's coastal marine ecosystems have received industrial waste with high nitrogen concentrations, generating the eutrophication of these ecosystems. Different physicochemical-biological technologies have been developed to remove the nitrogen present in wastewater. However, conventional technologies have high operating costs and excessive production of brines or sludge which compromise the sustainability of the treatment. Microbial electrochemical technologies (METs) have begun to gain attention due to their cost-efficiency in removing nitrogen and organic matter using the metabolic capacity of microorganisms. This article combines a critical review of the environmental problems associated with the discharge of the excess nitrogen and the biological processes involved in its biogeochemical cycle; with a comparative analysis of conventional treatment technologies and METs especially designed for nitrogen removal. Finally, current METs limitations and perspectives as a sustainable nitrogen treatment alternative and efficient microbial enrichment techniques are included.

Testing the Environmental Kuznets Curve Hypotheses in Chinese Provinces: A Nexus between Regional Government Expenditures and Environmental Quality

With rapid economic growth, the Chinese government expenditures at various levels have increased adequately. At the same time, the environmental quality in China has deteriorated significantly. In this study, provincial-level data for 31 Chinese provinces during 2007-2017 are used to investigate the impacts of government expenditure on the emissions of three specific measures of environmental degradation. The main objective of this study is to examine the influence of government expenditures, economic growth per capita, environment protection expenditure, and added second-sector value on environmental quality by measuring sulfur dioxide (SO₂), chemical oxygen demand (COD), and ammonia nitrogen emissions (AN). Moreover, the study applied the generalized method of moments (GMM) and the fully modified least square (FMOLS) to estimate the co-integration relationship among the underlying factors. The results demonstrate a significant direct effect of government expenditure on improving environmental quality overall in the Chinese provinces, which increases with the level of economic growth. However, the results also confirmed the inverted N-shaped relationship between the pollution factor and economic growth per capita. Our key findings lead toward the manifestation and emphasis of the importance of appropriate policies for restoring government expenditure and, at the same time, strengthening the relationship between the industrial sector and environmental policy standards. Significantly, governments in developing countries should allocate larger budgets for environmental projects in their fiscal reforms for the sake of moving to greener and more inclusive economies with low-carbon activities.

Ecological features of a rocky intertidal community exposed to sewage effluent

Sewage is among the largest components of coastal pollution, showing a variable scale and size when causing an impact. In this study, temporal and spatial sewage-related gradients were identified using univariate and multivariate methods. Phosphates and nitrogen-based nutrients, except nitrate, were associated to sewage. Abundance and species richness decrease with distance from the sewage outfall while evenness increased. Filter-feeder bivalves and grazer crustaceans showed preference for the sewage discharge site. Gastropods were more abundant at an intermediate distance, likely reflecting primary production enhancement by sewage. Beta diversity was lower at the location and time with highest sewage loadings. The turnover component of beta diversity expressed as an absolute or proportional value was also useful to detect temporal and spatial sewage-related gradients. Highly energetic hydrodynamics contributes to ameliorate sewage impacts, yet not enough to veil the effect of pollution in this study.

The pristine nature of river Ganges: its qualitative deterioration and suggestive restoration strategies

The river Ganges, the National Heritage, and the lifeline of millions of Indians, unfortunately, ranked the second most polluted rivers of the world in 2017. This review reveals the current trends of the water quality of the Ganges assessed around 36 stretches during 2012-2016, to indicate an improvement around 6 (16.7%), deterioration around 14 (38.9%), and non-significant changes around 16 (44.4%) stretches. An increase in dissolved oxygen and a decrease in biochemical oxygen demand were observed at six stretches (Devprayag [S₅], Rishikesh upstream [S₇], Varanasi upstream [S₁₉], Mokama upstream [S₂₅], Mokama downstream [S₂₆], and Munger [S₂₇]). The total and fecal coliform contamination decreased at seven stretches (Rudraprayag [S₂ and S₃], Devprayag [S₅ and S₆], Rishikesh [S₇], Varanasi upstream [S₁₉], and Munger [S₂₇]) due to improved hygienic conditions, but it increased subsequently at eight stretches (Haridwar [S₈], Kanpur [S₁₅], Raibareili [S₁₆], Prayagraj [S₁₇ and S₁₈], Patna [S₂₄], Berhampore [S₃₀], and Serampore [S₃₁]) due to improper defecation and mass bathing during 2007-2016. Dissolved oxygen level declined significantly, and biochemical oxygen demand increased (> 3 ppm), alarmingly at places receiving heavy untreated sewage water. The water quality of the Ganges was good up to Rishikesh, because of an undisrupted flow of the uncontaminated water from the higher altitudes (≥ 372 m) with higher forest cover, lower temperatures (< 21 °C), and higher dissolved oxygen (≥ 8.5 ppm) and due to the dissolution of antipathogenic chemical constituents of the medicinal herbs, pollutant degrading alkaline phosphatase, and bacteriophages. The present review is a systematic collection of data on river pollution, its scientific analyses, and its relationship with 6Ps (namely population, poverty, pollution, precipitation, plantation, and periodicity). Not only that, but the river water restoration measures have also suggested through the novel interlinked water working groups for implementing integrated water management strategies.

Restoring rocky intertidal communities: Lessons from a benthic macroalgal ecosystem engineer

As coastal population growth increases globally, effective waste management practices are required to protect biodiversity. Water authorities are under increasing pressure to reduce the impact of sewage effluent discharged into the coastal environment and restore disturbed ecosystems. We review the role of benthic macroalgae as ecosystem engineers and focus particularly on the temperate Australasian fucoid Hormosira banksii as a case study for rocky intertidal restoration efforts. Research focussing on the roles of ecosystem engineers is lagging behind restoration research of ecosystem engineers. As such, management decisions are being made without a sound understanding of the ecology of ecosystem engineers. For successful restoration of rocky intertidal shores it is important that we assess the thresholds of engineering traits (discussed herein) and the environmental conditions under which they are important.