Due to their widespread application in consumer products, elemental titanium (e.g., titanium dioxide, TiO₂) and silver (Ag), also in nanoparticulate form, are increasingly released from households and industrial facilities to urban wastewater treatment plants (WWTPs). A seven-day sampling campaign was conducted in two full-scale WWTPs in Trondheim (Norway) employing only primary treatment. We assessed the occurrence and elimination of Ti and Ag, and conducted size-based fractionation using sequential filtration of influent samples to separate particulate, colloidal and dissolved fractions. Eight-hour composite influent samples were collected to assess diurnal variations in total Ti and Ag influx. Measured influent Ti concentrations (up to 290 μg L⁻¹) were significantly higher than Ag (<0.15–2.1 μg L⁻¹), being mostly associated with suspended solids (>0.7 μm). Removal efficiencies ≥70% were observed for both elements, requiring for one WWTP to account for the high Ti content (∼2 g L⁻¹) in the flocculant. Nano- and micron-sized Ti particles were observed with scanning transmission electron microscopy (STEM) in influent, effluent and biosolids, while Ag nanoparticles were detected in biosolids only. Diurnal profiles of influent Ti were correlated to flow and pollutant concentration patterns (especially total suspended solids), with peaks during the morning and/or evening and minima at night, indicating household discharges as predominant source. Irregular profiles were exhibited by influent Ag, with periodic concentration spikes suggesting short-term discharges from one or few point sources (e.g., industry). Influent Ti and Ag dynamics were reproduced using a disturbance scenario generator model, and we estimated per capita loads of Ti (42–45 mg cap⁻¹ d⁻¹) and Ag (0.11 mg cap⁻¹ d⁻¹) from households as well as additional Ag load (14–22 g d⁻¹) from point discharge. This is the first study to experimentally and mathematically describe short-term release dynamics and dry-weather sources of emissions of Ti and Ag in municipal WWTPs and receiving environments.

由于它们在消费产品中的广泛应用，越来越多的元素钛（例如二氧化钛，TiO ₂）和银（Ag）也以纳米颗粒的形式从家庭和工业设施释放到城市废水处理厂（WWTP）中。在特隆赫姆（挪威）的两个全面污水处理厂进行了为期7天的采样活动，仅采用初级治疗。我们评估了钛和银的发生和消除，并使用进样的顺序过滤进行了基于尺寸的分级分离，以分离出颗粒，胶体和溶解级分。收集了八小时的复合进水样品，以评估总Ti和Ag进水量的日变化。测得的进水Ti浓度（高达290μgL ^-1）显着高于银（<0.15–2.1μgL ^-1），主要与悬浮固体（> 0.7μm）有关。两种元素的去除效率均≥70％，需要一个污水处理厂才能解决高钛含量（〜2 g L ^-1）中的絮凝剂。用扫描透射电子显微镜（STEM）观察到了进水，出水和生物固体中的纳米和微米级钛颗粒，而仅在生物固体中检测到了银纳米颗粒。进水Ti的昼夜分布与流量和污染物浓度模式（尤其是总悬浮固体）相关，早晨和/或傍晚达到峰值，晚上极少，表明家庭排放是主要排放源。进水银表现出不规则的分布，周期性的浓度峰值表明从一个或几个点源（例如，工业）的短期排放。使用干扰情景生成器模型复制了进水Ti和Ag动力学，我们估算了人均Ti负荷（42–45 mg cap ^-1 d ^-1）和来自家庭的Ag（0.11 mg cap ^-1 d ^-1）以及点放电产生的额外Ag负荷（14-22 g d ^-1）。这是第一项以实验和数学方式描述市政污水处理厂和接收环境中Ti和Ag排放的短期释放动态和干旱天气源的研究。