Shikun Cheng

Toilet revolution in China.

The wide-spread prevalence of unimproved sanitation technologies has been a major cause of concern for the environment and public health, and China is no exception to this. Towards the sanitation issue, toilet revolution has become a buzzword in China recently. This paper elaborates the backgrounds, connotations, and actions of the toilet revolution in China. The toilet revolution aims to create sanitation infrastructure and public services that work for everyone and that turn waste into value. Opportunities for implementing the toilet revolution include: fulfilling Millennium Development Goals and new Sustainable Development Goals; government support at all levels for popularizing sanitary toilet; environmental protection to alleviate wastewater pollution; resource recovery from human waste and disease prevention for health and wellbeing improvement. Meanwhile, the challenges faced are: insufficient funding and policy support, regional imbalance and lagging approval processes, weak sanitary awareness and low acceptance of new toilets, lack of R&D and service system. The toilet revolution requires a concerted effort from many governmental departments. It needs to address not only technology implementation, but also social acceptance, economic affordability, maintenance issues and, increasingly, gender considerations. Aligned with the ecological sanitation principles, it calls for understanding issues across the entire sanitation service chain. Public-private partnership is also recommended to absorb private capital to make up the lack of funds, as well as arouse the enthusiasm of the public.

Development and application of biogas project for domestic sewage treatment in rural China: opportunities and challenges

The biogas project for domestic sewage treatment (BPDST) is considered a promising facility for wastewater management in rural areas of China. This paper explores previous experimental works, cost analysis, and BPDST structure and design based on Chinese literature. Opportunities for developing decentralized or neighborhood-based BPDSTs include fulfilling Millennium Development Goals (MDGs) and Sustainable Development Goals (SDGs), the water pollution situation and deficiency of wastewater treatment facilities, the advantages of BPDSTs compared with centralized sewage plant, government support and policy drive for rural wastewater treatment, and reuse demand for resources. Meanwhile, challenges faced are emphasized as follows: uncertain responsibility for BPDSTs under different governmental departments restricts BPDST development and should be specified; uncertain effluent quality due to low efficiency of nutrient removal requires aerobic post-treatment to some extent; rural environmental awareness is still low and should be heightened; more funds should be invested in R&D for improvement of technology innovation; more reuse and resource recovery elements should be considered during implementation; follow-up services are lacking and should be improved; and BPDST maintenance should be trained. This paper could provide valuable reference for other developing countries.

Evaluation of a closed-loop sanitation system in a cold climate: a case from peri-urban areas of Mongolia

This study examines a closed-loop sanitation system (CLSS) in the ger areas (informal peri-urban settlements) of Ulaanbaatar, Mongolia in order to evaluate system feasibility and to identify the future prospects of CLSS as an alternative to conventional sanitation and drainage options. Results show that the CLSS concept is well understood and accepted by users and that services are being scaled up. Over 50 per cent of respondents used CLSS technologies during both winter and summer, testifying to the potential for scaling up these technologies and services. Moreover, all users responded positively in their evaluation of the emptying services. Despite some problems and challenges, the system proved to be feasible, replicable and acceptable in the study area. It is recommended that the entire CLSS approach be tested through scientific validation to convince more communities, government and other stakeholders about scaling up the system beyond the study area for better health, environmental conservation and resource recovery.

Diminished inhibitory impact of ZnO nanoparticles on anaerobic fermentation by the presence of TiO2 nanoparticles: Phenomenon and mechanism

Engineered nanoparticle materials (ENMs) are widely and increasingly produced and employed in many sectors. The use of diverse ENMs potentially leads to the release of multiple ENMs into the environment. These ENMs after discharge will be end in wastewater treatment plant and present in sludge. This work investigated the effect of multi-ENMs systems of ZnO and TiO2 on sludge anaerobic fermentation and the related toxicity mechanism. Results revealed that the toxicity of ZnO ENMs on anaerobic fermentation was reduced in the presence of TiO2 ENMs. Investigation on the change of free Zn2+ and reactive oxygen species (OH and H2O2) suggested that both of free Zn2+ and ROS contributed to the toxicity mechanism. Zn2+ decrease was the main reason for the reduced toxicity in multi-ENMs systems. ROS mainly led to the reduction of cell viability in anaerobic fermentation systems. The presence of TiO2 in the multi-ENMs systems promoted the recovery of enzyme activity, cell viability and bacteria abundance.