a) Composting of Organic Waste in Hong Kong

The organic waste generation from Hong Kong, which is about 4,664 tonnes per day in 2008, creates a serious burden on our landfills. It is estimated that in 8 to 10 years time our landfills would be running out of space and therefore developing alternative treatment technologies for organic waste to divert it from landfilling is urgently searched. Composting as a common technology for treating various types of organic waste by converting them into useful fertilizer products. However, one of the main concerns of composting in Hong Kong is that generation of odour during the composting process which may create environmental nuisance to the residents. Therefore the aim of this research focus was to develop a feasible means for treating organic waste generated in Hong Kong.

b) Bioremediation of Soil Contaminated by Persistent Organic Pollutants

Soil contaminated with Persistent Organic Pollutants (POPs), i.e., DDT, lindane and polycyclic aromatic hydrocarbons (PAHs) pose a significant impact on the soil ecosystem and the quality of food produced. Bioremediation has been demonstrated as a promising and cost saving alternative for removal the POPs from soil. The aim of this research focus to establish a novel approach for bioremediation of soil contaminated with POPs by incorporating biosurfactant or microemulsion with bioremediation.

c) Converting food waste to renewable energy by anaerobic digestion

Anaerobic digestion, a growing waste treatment technology, appears to be another promising biological treatment technology for organic wastes because it can provide energy and nutrient recovery from food waste; consequently increasing the lifespan of our existing landfills. Variety of anaerobic reactor designs available around the world and recently a two-phase anaerobic system, separating the acidogenesis and methanogenesis to improve the efficiency, was suggested to negate the problems of food waste anaerobic digestion. However, hydrolysis is the rate-limiting step of anaerobic digestion of solid or semi-solid wastes, whereas methanogenesis is considered rate-limiting for fermentation of soluble substrates. Hence, our study aims to improve the methane production from food waste we apply a hybrid anaerobic solid-liquid system.

d) Degradation pattern of antibiotics in composting process

The extensive use of antibiotics in livestock industries results in pharmaceutical residues in manure subsequently to the soil. Water seepage from the livestock industries, soils applied with manure and STP effluents contribute to the presence of antimicrobial agents in the surface and river waters. Development of antibiotic resistance in the commensal and subsequent transfer of resistance genes to the pathogenic organisms cannot be ruled out.

To understand the situation as well as mitigate the problem, we are conducting research and targeting to provide an in-depth understanding of the behaviour and fate of antibiotics derived from livestock excretions during composting; and also develops a more effective composting technology to prevent the accumulation of veterinary antibiotics in soil.

e) Develop waste separation model for small cities in the Pearl River Delta

Our previous work done at Heng County, Guangxi Province has demonstrated that a low cost feasible waste management model by separate waste into various fractions which will facilitate the recycling of organic waste for future utilization for composting. This reduces the need of landfill space and also prevents the illegal dumping of MSW on agricultural land and subsequent adverse impact on food quality. The same model will be further tested in two different sites in Guangdong to reconfirm the feasibility of this waste management models in County as well as at village level.

f) Antibiotics residues in river, potable water and soil environment of Hong Kong and DongJiang region

Hong Kong receives most of its drinking water from the Pearl River, particularly from the DongJiang. From the last decade, the “Pearl River Delta” became the most rapidly developed industrial area in China and a drastic increase in the level of pollution in the Guangdong Province. Although our drinking water is reported to be clean for conventional parameters, profiles of antibiotics are not analyzed and not available. The antibiotics residues in the environment are resulting in the development of antibiotic resistant bacteria in the soil and water environments. Monitoring programme will be undertaken in the river bodies and soil environment in Hong Kong and South China to study the existence of antibiotics. Detection of antibiotics in the selected rivers in Hong Kong will disclose the possible risks posed by the existence of antibiotics in our aquatic environment.

g) Combined treatment system with novel filtering system and floating garden to mitigate river pollution

A system combining an innovative proprietary filter system from USA and a wetland wastewater treatment system is investigated to treat the intermittent pollutant discharge to local rivers. The proprietary filter system has been proved to be effective to reduce E. Coli in the water bodies in USA before. On the other hand, aquatic plant species with high pollutant tolerance such as Zizania caduciflora, Cyperus spp., Cannas spp. will be employed in the treatment system with the proprietary filter system to enhance the nutrient removal efficiency, the aesthetic values of the river is also targeted to be enhanced by the provision of floating garden assembling all these aquatic plants.
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