Can water treatment residual be useful? A preliminary investigation in the Canadian Prairies

饮用水处理是现代社会中保护公众健康的必要条件。混凝法是目前世界上应用最广泛的去除水中颗粒物和胶体物质的水处理工艺，其产生大量的水处理残渣（WTR）。由于明矾（水合硫酸铝盐）是最常用的混凝剂，铝基污泥是最常见的WTR。传统上，铝基污泥的处理主要有填埋和农用两种方式。前者费用高昂，而后者由于担心土壤健康状况恶化，可能难以在农业生产者中找到意愿。该项目的合作伙伴每年支付100多万美元填埋其铝基污泥，这是一个沉重的财政负担。根据主要内容，例如，铝基污泥中的Al、Si和Ca，铝基污泥可制成吸附剂、砖、陶粒和混凝土等增值产品。我们将与合作伙伴共同探索将管理成本高昂的废物转化为可销售产品的可能性。本项目的主要目的是初步探索利用工业合作伙伴设施产生的废水流（含铝污泥）开发增值产品的可能性。具体目标是：1）对铝基污泥的价值化进行系统的文献研究; 2）表征不同季节工厂产生的铝基污泥; 3）探索直接再利用铝基污泥去除水体基质中的新兴污染物。该项目不仅将帮助合作伙伴进一步加强其环境管理，还将降低运营成本，甚至开辟新的盈利机会。这种奋进也对该地区和加拿大的可持续发展产生影响。

Drinking water treatment is essential to the protection of public health in the modern society. Coagulation is the most widely used water treatment process in the world for particulate and colloidal matter removal from water, which results in large quantities of water treatment residual (WTR) production. As alum (hydrated aluminum sulfate salt) is the most commonly used coagulant, aluminum-based sludge is the most common WTR. Traditionally landfilling and agricultural application are the two common strategies of aluminum-based sludge management. The former is costly and the second may have difficulty in finding willingness among agricultural producers due to the concern of deteriorating soil health. The partner of this project pays over $1 million annually to landfill its aluminum-based sludge, which is a heavy financial burden. In light of the main elements, e.g., Al, Si, and Ca, in aluminum-based sludge, aluminum-based sludge may be made into value-added products such as adsorbent, bricks, ceramsite, and concrete. We will work with the partner to explore the possibility of transforming a costly to manage waste into marketable products. The main goal of this project is to preliminarily explore the possibility of developing value-added products using wastewater stream (aluminum-based sludge) generated at the industrial partner's facility. Specific objectives are: 1) Conduct systematic literature research on valorization of aluminum-based sludge; 2) Characterize the aluminum-based sludge generated at the plant in different seasons; and 3) Explore directly reusing aluminum-based sludge for emerging pollutant removal from water matrices. The project will not only help the partner to further enhance its environmental stewardship but also reduce operational costs or even open up new profit opportunities. Such an endeavor also has implications to the sustainable development of the region and Canada.