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Problems & Solutions

Kowloon Bay Pilot Composting Plant

   
     

Background

   
     
Composting UnitTo gather experience and information on collection of source separated food waste and the application of biological technology to recycle food waste in Hong Kong, the Environmental Protection Department developed the Pilot Composting Plant (KBPCP) at the Kowloon Bay Waste Recycling Centre (KBWRC) in mid-2008. 
 
In-vessel composting technology is chosen for the KBPCP because of the numerous merits of relatively small footprint, short processing time and easy control on environmental impacts.
   
     

Food Waste DeliveryThe Pilot Plant consists of an enclosed pre-treatment area, two composting drum units, curing pads, product screens and biofilters. The total treatment capacity of the KBPCP is 500 tonnes of food waste feedstock per year and about 50 tonnes of compost product can be produced.

After commissioning, the Pilot Plant was first used to treat the food waste generated at the Olympic and Paralympic Equestrian Event venues in August and September 2008. This was followed by a 1-year trial operation for recycling of source-separated food waste generated from 19 waste generators from the following sectors.

   
     

Sectors

Type of Waste

Food Production Factory

Bean curd waste

Lunch box caterers

Post-consumption food

Hotel

Food processing and post-consumption food

Shopping Mall

Food processing and post-consumption food

Supermarket

Food processing

Chinese Restaurant

Food processing and post-consumption food

Western Restaurant

Food processing and post-consumption food

Bakery

Food processing

In-flight catering service

Food processing

Wet Market

Vegetables, fruit and meat

Food Production Centre

Food processing

Fast Food Restaurant

Coffee and tea residue

Charity Organization

Food processing

   
     
Treatment Process    
     

Treatment Process

   
     
Sorting Facility  Mixing Facility  In Vessel Composting  Biofilter  Curing Facility  Product Screen      
     

Pre-treatment
Source separated food waste delivered to the pilot plant is firstly taken to the enclosed area for manual sorting and draining of excessive waste water. The food waste is then mixed with bulking agents (e.g. saw dust, bark chips) to achieve optimum porosity and moisture content for the subsequent composting process.

   
     

Composting
The mixed waste is then fed to the composting drum units. Decomposition of food waste by biological bacteria action takes place inside the drum. Heat is released during the decomposition process. Temperature inside the drum is kept between 55oC and 70oC for pathogens killing and optimum decomposition.

   
     

Curing
After residing inside the composting drum for 10 days, the waste material becomes premature compost and is discharged. The premature compost is then piled on the curing pads to undergo a curing period of about 30 days to ensure complete decomposition. During the curing period, tilling and water spraying on the compost pile are carried out regularly to maintain optimum condition for decomposition.

   
     

Final Products
After curing, the mature composts are sieved by a vibrating product screen to remove bulking agents and contaminants before they are packed for delivery to the users. Bark chips screened out from the mature compost is reused in the composting process as bulking agents.

   
     

Application of Compost
Use of compost to farming soil improves the soil structure and water retention ability. The compost also reduces soil erosion rate and suppress diseases. The compost product from the KBPCP could be used for landscaping, vegetable and fruit production.

   
     
 
Landscaping   Vegetable/Crop Production   Fruit Production
   
            Landscaping                       Vegetable/Crop Production                     Fruit Production             
     

Compost Sampling and Environmental Monitoring
Regular compost testing and environmental monitoring are conducted to ensure satisfactory compost quality and that the environmental impacts of the KBPCP operation are kept within acceptable standards.

   
     
 Latest Progress    
     

In late 2009, EPD and the trades has set up a Food Waste Recycling Partnership Scheme to promote food waste reduction and recycling. As part of the Scheme, starting from mid-2010, the KBPCP would receive source-separated food waste collected from the participants of the Scheme for recycling to useful products.

   
     
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User review date: 
Tuesday, 17 September, 2013