ENVIROMAIL #HK00 September 2012 ENVIROMAIL #HK012 May 2013

Introduction

Compost is organic material and as a fertilizer to grow plants. The texture of mature compost is dark brown or black and has a soil-like texture and earthy smell.

In Hong Kong, EPD has developed the Pilot compost plants. For example, Kowloon Bay, Yam O. EPD has also promoted the various funding projects such as “Food Waste Recycling Projects in Housing Estates” to encourage the recycling of food waste from households.

Sources for compost – Food processing wastes, Post-Consumption Food, Animal Waste and etc.

Compost and Soil Conditioner Standards Hong Kong Organic Resource Centre (HKORC) is established the standard for compost and soil conditioner in 2005 and provide an independent incorporated certification (Organic Certificate).

The compost quality standard is consisted of four categories:

1) Compost Maturity:

Ammonia, Oxygen demand, Volatile Organic acid and etc.

2) Compost Quality:

Foreign matter, Heavy metals, Physicochemical Properties and Pathogen

3) Nutrient Content

Nitrogen, Phosphorus and Potassium (NPK)

4) Seed Germination Index (SGI)

ALS (HK) is providing a testing service on Compost and Soil Conditioner Standards.

Method Reference: The Testing Method for the Examination of Composting and Compost (TMECC)

American Public Health Association (APHA)

Hong Kong Organic Resource Centre (HKORC) for SGI.

The Criteria for Soil and Soil Conditioner Classification:

Compost Maturity

Compost Quality

Seed Germination

Index

Nutrient content

Good Quality

Compost used as Fertilizer

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Compost used as Soil Conditioner

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Pass

Compost used as Fertilizer

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Compost used as Soil Conditioner

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The procedure of Composting

For More Information: Please email to cs_env.alshk@ALSGlobal.com

or call us at +852 2610 1044

Address:

11/F, Chung Shun Knitting Centre,

1-3 Wing Yip Street, Kwai Chung,

N.T., Hong Kong

Class Test

Food Waste Rotary in-vessel composter

Table for the Limit of Compost and Soil Conditioner Standards

Parameter In House Method Limit of Reporting Limit

Ammonia TMECC 04.02C +

APHA 4500 NH3:G 10 mg/kg

≤ 700 mg/kg dw

Ammonia :Nitrate Ratio TMECC 05.02C -- ≤ 3

Volatile organic acid APHA 5560C 50 mg/kg ≤ 500 ppm dw

Carbon :Nitrogen Ratio TMECC 05.02A --- ≤ 25

Oxygen Intake Rate TMECC 05.08-A 0.1g O2/kgTS/hr ≤ 0.4 g O2/kg TS/hr

Carbon Dioxide Evolution Rate TMECC 05.08-B 0.1g C/kg VS/day ≤ 2 g C/kg VS/day

Stone larger than 5mm

TMECC 03.08-A 0.1% ≤ 5% dw

Man-made Foreign Matters such as glass and plastic and metal larger than 2mm

0.1% ≤ 0.5% dw

Arsenic TMECC 04.06 +

USEPA6020 1 mg/kg ≤ 10

Cadmium 1 mg/kg ≤ 1

Chromium 1 mg/kg ≤ 100

Copper 1 mg/kg ≤ 300

Mercury 1 mg/kg ≤ 1

Nickel 1 mg/kg ≤ 50

Lead 1 mg/kg ≤ 100

Selenium 1 mg/kg ≤ 1.5

Zinc 1 mg/kg ≤ 600

pH value TMECC 04.11 0.1 pH unit 5.5 – 8.5

Organic matter TMECC 05.07A 0.1% > 20% dw

Moisture content TMECC 03.09A 0.1% 25 – 35%

Salmonella TMECC 07.02-A1-2 3 MPN/4g ≤ 3 MPN/4g

E. coli TMECC 07.01-B 3 MPN/g ≤ 1000 MPN/g

Nutrient

Content

Total Nitrogen (as N) TMECC 04.02A +

APHA 4500 Norg

10 mg/kg

Total N + Total P +

Total K

≥ 4% dw Total Phosphorus (as P2O5) TMECC 04.04A 10 mg/kg

Total Potassium (as K2O) TMECC 04.03A 10 mg/kg

Seed Germination Index HKORC 2005 1% ≥ 80%

Remark : The limit of heavy metals is applied for Organic Farming. Product must pass one of tests from Group A and one of the tests from Group B. Source: Hong Kong Organic Resource Centre.