A high moisture content of waste activated sludge (WAS) associated with a low calorific value needs to be deeply dried towards self-supporting incineration. On the other hand, thermal energy with low temperature exchanged from treated effluent has great potential for drying sludge. Unfortunately, low-temperature drying of sludge seems to be low in efficiency and long in drying time. For this reason, some agricultural biomass was added into WAS to improve the drying efficiency. The drying performance and sludge properties were analyzed and evaluated with this study. Experimental results demonstrated that wheat straw was the best in enhancing the drying performance. With only 20 % (DS/DS) of crushed wheat straw added, the average drying rate achieved up to 0.20 g water/g DS·min, much higher than 0.13 g water/g DS·min of the raw WAS. The drying time to the targeted moisture content (63 %) (for self-supporting incineration) was shortened to only 12 min, much lower than 21 min of the raw WAS. The analysis revealed that wheat straw could reduce the specific resistance of filtration (SRF) and increase the sludge filterability (X). Also, the sludge rheology, particle size distribution and SEM images could conclude that agricultural biomass played a positive role in skeleton builders, forming a mesh-like structure in sludge flocs. These special channels could obviously improve the transfer capacities of heat and water inside the sludge matrix and thus greatly increase the drying performance of WAS.

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Alginate like extracellular polymers (ALE) recovered from flocculent sludge has been identified as a kind of highly valuable biomaterials. However, the extraction protocols limit the production of biopolymers as ALE extracted from flocculent sludge is at a lower level, around 90–190 mg/g VSS. Under this circumstance, the eco-friendly and effective optimizations for the ALE extraction protocols are expected, and thus surfactants have gained an attention to enhancing the ALE extraction. With this study, different surfactants with different structures and chemical characteristics, such as sodium dodecyl sulfate (SDS), cetyltrimethylammonium bromide (CTAB) and octyl phenyl polyoxyethylene ether (Triton X-100), were experimented to improve the ALE extraction, and in turn the optimal conditions and the associated mechanisms were evaluated and figured out. The experimental results indicated that surfactants could enhance the ALE extraction but also improve the alginate purification of ALE. With the optimal dosage of surfactants, the ALE extraction increased from 124.1 mg/g VSS to about 222.8–281.9 mg/g VSS, and the alginate purify was at around 54%–70%, in which the efficiency of the ALE extraction was improved by 79.5%–127.2%. Among others, Triton X-100 had the best performance on improving the ALE extraction, followed by CTAB and SDS. The mechanisms of surfactants on enhancing the ALE extraction and improving the alginate purify can be attributed to: i) surfactants micelles, which can solubilize flocs and extracellular biopolymers; ii) similar structures of surfactants and ALE, which follows the rule of “like dissolves like”; iii) functional groups adsorption, which facilitates the ALE release from matrixes. In a word, the optimized extraction protocol by using surfactants can be effectively applied to extract ALE from flocculent sludge.

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The designation of cultural heritage, especially the World Cultural Heritage Site, is extensively discussed regarding its impacts on tourism destination branding. However, the impact of the designation(s) of World and/or National Cultural Heritage Site on affective city image and behavioural intention is still under-researched. This study aims to investigate the respective impact of visitors’ awareness of the world and national heritage status on existential authenticity perceived at the heritage site, affective city image, and behavioural intention. The quantitative research method was employed to test the proposed structural model. A structured questionnaire was sent, and 363 valid responses were collected from domestic visitors at the Xiaoling Tomb of the Ming Dynasty, China. The results demonstrate that cultural heritage designation, whether it is a world or a national one, when recognised by domestic visitors, determines the shaping of a positive affective image of the city hosting the heritage site, as well as visitors’ future intentions. However, visitor awareness of the world status and national status does not condition the affective city image and behavioural intentions in the same manner. This research takes the lead to stress the significant role of national heritage status in city branding and urges managerial attention@en

The UNESCO 2011 Recommendation on the Historic Urban Landscape (HUL) states community participation is a pivotal tool for integrating heritage practices into sustainable urban development. While community participation is significant but limited in China, various participatory methods have been developed, tested and evaluated worldwide. For example, inspired by HUL, the Ballarat Imagine in Australia has successfully used public engagement in the development of a community vision for local conservation and development. This paper aims to contextualise community participation in China, by testing and adapting a community participatory method, the (Ballarat) Imagine. Imagine was tested in the Old Town of Lijiang as an academic scoping exercise, to critically examine its viability and potential for contextualisation to the Chinese context. During the fieldwork, three workshops were organised with residents in Dayan, Shuhe and Baisha, which are the three housing clusters constituting the World Heritage property. In the workshops, residents responded to three sets of questions focussing on their feelings about local historic urban landscape as well as their ideas about future public engagement in local heritage management. This paper discusses the contextualised approach of community participation tailored to the management of the Old Town of Lijiang, and also China as a whole, seeking to find a balance between top-down and bottom-up processes. This academic exercise confirmed that the community participatory method, the Imagine, can be further adapted to the Chinese context. Further research could test it in other cities, to better face the challenges of rapid urbanisation.

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Extracellular polymeric substances (EPS) are biopolymers that can be recovered from excess sludge, which could contribute to a more sustainable wastewater treatment plant (WWTP) operation. An example is alginate like extracellular polymers (ALE) contained in the biopolymers could be a potential resource with a highly-added value. EPS extraction for ALE from aerobic granules sludge (AGS) has already been well studied and applied in the Netherlands. On the other hand, there is little attention to the recovery of biopolymers from conventional activated sludge (CAS). In this study, flocculent sludge from eight CAS-WWTPs in China was collected and their EPS/biopolymers were extracted to investigate their recovery potential, chemical & physical properties and limiting factors. The results revealed that the biopolymers extracted and purified from CAS ranged from 90 to 190 mg/g VSS. The compositional characteristics of the biopolymers were observed by FT-IR, 3D-EEM and UV-Visible spectra, demonstrating some differences in the composition and property of the biopolymers from the different WWTPs. The biopolymers had a similarity of about 60% to a commercial alginate with respect to chemical functional groups and the alginate equivalent was >400 mg/g biopolymers. Moreover, the biopolymers consisted of poly (guluronic acid) blocks (20%-30%) and poly (guluronic acid-mannuronic acid) blocks (8%-28%), and the ionic hydrogel formation tests indicated that condensed beads were immediately formed once the drops of the biopolymers came in contact with CaCl₂ solution. These results demonstrated that the biopolymers extracted had a relatively high gel-forming capacity and might also have a potential application as commercial biopolymers. Furthermore, the factors influencing the biopolymers’ formation such as influent substrate, nutrient content and microbial community and the related mechanisms were investigated. Among them, increasing soluble organics (SCOD) content and low nutrient content (C/N/P) in the influent could promote the biopolymers’ formation. Also, different bacteria in BNR processes might have positive or negative effects on the biopolymers’ formation. In conclusion, the diversity and abundance of bacteria were identified to be a crucial and decisive factor controlling biopolymers’ extraction and composition.

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