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Problems & Solutions

Livestock Waste

What is "Composting" ?

Composting is not a new waste treatment technology. It has been widely practiced by gardeners and farmers all over the world as a sustainable means of returning nutrients to the soil. The process of composting transforms organic waste such as livestock waste into useful soil conditioner or fertilizer. As compost is stable and readily assimilated by soil, it can enhance soil structure and help prevent soil erosion. As the crop agriculture industry in Hong Kong is small, the potential uses of compost are mainly for landscaping, golf course and race course maintenance, and horticulture industry.
 

Location of Sha Ling Livestock Waste Composting Plant (SLCP) and Animal Waste Composting Plant (AWCP)

Please click the spot for information of SLCP and AWCP
 
Map of Hong Kong
 

Sha Ling Livestock Waste Composting Plant (Operations have been stopped since October 2010)

Background information

To combat pollution from the discharge of untreated livestock waste to watercourses, EPD introduced the Livestock Waste Control Scheme in 1987 and amended it in 1994. This Control Scheme bans livestock keeping in those areas designated as Prohibition Areas. Livestock keepers operating in other areas can continue to rear livestock provided that they handle the waste properly and treat it to the required effluent standards before discharge. Water pollution caused by livestock waste has been substantially reduced since the Control Scheme became effective.
To assist the livestock farmers in disposing of livestock waste in an environmentally acceptable manner, the government provides them with:
  • Technical assistance by publishing Code of Practice and guidance notes on waste treatment options and setting up demonstration treatment plant in private farms
  • Financial assistance in the form of capital grant for installation of waste treatment facilities
  • A free livestock waste collection service 
With regard to the livestock waste collection service, EPD has appointed a contractor to provide free waste collection bins to the livestock farmers in need of the collection service and collect the livestock waste from the farms on a regular basis. The contractor delivers the livestock waste collected to composting plant for composting. When the amount of livestock waste collected exceeds intake capacity of the composting plant, the surplus livestock waste is delivered direct to landfills for disposal. If you want to know more information about the Livestock Waste Control Scheme, click here.
 

Operation Details

The contractor provides leak-proof collection bins to livestock farmers for containing livestock waste generated from their farms. Livestock waste is collected by the contractor's collection vehicles on a regular basis. Part of the livestock waste is delivered to the composting plant for composting and the remaining is disposed of at landfill sites. On arriving the composting plant, the livestock waste is mixed with shredded wooden pallets. The mixed material is placed within fermentation box up to a height of 2.5 metres. Air is blown through the material by air pipes that are laid in the concrete floor of the fermentation box. Within a period of 6-8 weeks, fermentation is completed and the semi-matured compost is transported to maturation shed for further maturation. When matured, the compost is sold as soil conditioner and the quality of the compost is monitored by testing conducted on the compost samples. The quality of matured compost will be subject to monitoring by sample test up before it is sold as soil conditioner.
 
Image of Livestock Waste Collection
Image of Use of Shredded Wooden Pallets as Mixing Pallets
Livestock Waste Collection
Use of Shredded Wooden Pallets as Bulking Agents
 
Mixing of Shredded Wooden Pallets and Pig Waste
Compost at Fermentation Boxes
Mixing of Shredded Wooden Pallets and Pig Waste
Compost at Fermentation Box
 
Compost at Fermentation Boxes
Image of Compost at Maturation Shed
Compost at Fermentation Boxes
Compost at Maturation Shed
 

Animal Waste Composting Plant

Background information

The Animal Waste Composting Plant (AWCP) is specially designed by using in-vessel composting technology which turned the horse stable waste generated during the 2008 Olympic and Paralympic Equestrian Events in Hong Kong into useful compost. It has a design capacity to treat around 20 tonnes of horse stable waste every day, comprising horse manure, straw or paper bedding materials, and horse feed etc. These wastes are rich in organic content and can be converted into useful organic compost suitable for landscaping, horticultural and agricultural uses. 
 
 
The AWCP was upgraded in mid 2012 to increase the maximum design treatment capacity to 40 tonnes per day. It also enables co-composting of horse stable waste with other types of organic wastes including pig waste and yard waste (such as grass clippings and leaves) for improving the quality of compost produced through trials.

With respect to the free livestock waste collection service, the AWCP contractor is appointed to provide free collection bins to livestock farms in need of the service, collect livestock waste from the farms on a regular basis and deliver the livestock waste collected to landfills for disposal. 
 
AWCP is located at Ngau Tam Mei in the Yuen Long District. The project manager is Electrical and Mechanical Services Department.
 

In-vessel Composting

In-vessel composting takes place within a fully enclosed rotary composter. This enables better control of moisture content and temperature during the treatment process.
 
In-vessel composting also enables:
  • Production of a more consistent quality compost
  • Reduced use of bulking agent
  • Better odour control as potentially odorous air from the process can be easily collected for treatment
  • Smaller footprint as compared with other composting methods
 
Rotary in-vessel composter
 
Operation Details
Collection trucks deliver the horse stable waste to the AWCP and unloaded at the pre-treatment plant. Here, the unloaded waste is tested for moisture content. Waste is then fed into a hopper and is conveyed through a ferrous magnet separator, a non-ferrous metal separator and a disc screen where metals, non-ferrous materials and plastics in waste are removed. Waste is further mixed by a mixer before feeding by conveyors into the in-vessel composters for around 3-4 days of biodegradation. Odour arising from the process is eliminated by contact de-odourizer. The semi-matured compost is transferred into bunkers for curing about 42 – 45 days. After curing, quality of the mature compost is tested before it is marketed.
 
Pre-treatment building where waste is received and pre-treated
Pre-treatment process for feedstock preparation
 Rotary in-vessel composter where bio-degradation takes place
Bunkers for compost maturation
Deodorisation system using Bio-filters
Raw horse stable waste Compost after 33 days
 
User review date: 
Friday, 16 October, 2015