REPEAT APPLICATION OF BIOSOLIDS ON AGRICULTURAL LAND

摘要

Land application of biosolids is an important component of beneficially using solid wastes from sewage treatment processes. The aim of many water authorities is to achieve 100% beneficial use of biosolids. To achieve this, repeat application of biosolids to the same site nearby is a useful strategy, as transport costs are minimised and fertiliser requirements at the site of application can be met while improving soil organic matter content. A one-in-five-year "repeat application tradition" is generally practiced across the water industry in Victoria.rnThis "one-in-five-year norm" anecdotally seems to have originated from the world's best management practices during the earlier stages of schemes involving land application of biosolids, as a conservative approach. However, there appears to be no one regulatory document available that states this 'rule'. Our knowledge and understanding of biosolids' chemical and physical risks (beneficial and detrimental) has improved considerably over the last few decades and it is time to reconsider the guidance offered for the practice of beneficial land application of biosolids.rnThis paper reviews the current Australian and overseas regulations governing repeat application of biosolids, and the set of rules that govern repeat applications, and defines what is currently considered best practice. Recommendations as to revisions and improvement of the current guidance for beneficial land application of biosolids is suggested as a first step in embracing a transparent risk-assessment-based strategy for the future.