Composting is a major method of sewage sludge treatment.Organic compost bulking agents such as woodchips and wheat straw are used during sewage sludge composting to adjust MC and free air space(FAS)of composting materials to guarrantee sewage sludge treatment,but are degradable and easily lost,therefore are not likely to be reused,which leads to high costs of sewage sludge composting,and can contribute to the final mass of compost.