Struvite precipitation is a well-documented method for recovering up to 98% of phosphorus from urine, which is one of the main nutrients in fertilizers besides nitrogen and potassium. Shortcomings of this process, however, are the low nitrogen recovery ratio and the possible uptake of pharmaceuticals from urine. In this work, the NH₄⁺ adsorbent materials biochar and zeolite are coupled with struvite precipitation to increase the N-recovery of struvite from 5.7% to 9.8%. Since nitrogen is one of the main nutrients in fertilisers, this increase is of significance for its potential commercial use. In addition, urine is spiked with pharmaceuticals to measure the consequential uptake in struvite-based fertilisers and crops afterwards. Five fertilisers are prepared by nutrient recovery from spiked urine using: (1) struvite crystallisation, (2) struvite crystallisation combined with N adsorption on zeolite, (3) struvite crystallisation combined with N adsorption on biochar, (4) N adsorption on zeolite without struvite crystallisation, and (5) N adsorption on biochar without struvite crystallisation. The fertilizer with the highest purity product and the lowest uptake of pharmaceuticals was struvite combined with zeolite.

Next, the contaminated struvite-sorbent fertilisers are tested in a crop trial in which the bioaccumulation of pharmaceuticals in edible plant tissue (tomatoes) is measured. This bioaccumulation in tomato fruit biomass from each of the spiked fertilisers in the crop trial was found to be lower than 0.0003% in all cases, far below the acceptable daily intake (ADI) levels (750 kg of dry tomatoes should be consumed per day to reach the ADI limit). Consequently, the subsequent risk to human health from tomato fruit grown using urine derived struvite-sorbent fertilisers is found to be insignificant.

鸟粪石沉淀法是一种有据可查的方法，可从尿液中回收高达98％的磷，磷是肥料中除氮和钾外的主要营养元素之一。但是，该方法的缺点是氮的回收率低，并且可能从尿液中吸收药物。在这项工作中，NH ₄ ⁺吸附剂材料生物炭和沸石与鸟粪石沉淀结合，将鸟粪石的氮回收率从5.7％提高到9.8％。由于氮是肥料中的主要养分之一，因此这种增加对其潜在的商业用途意义重大。此外，在尿液中掺入一些药物，以测定随后在鸟粪石基肥料和农作物中相应摄取的尿素。通过从加标尿液中回收营养物来制备五种肥料，方法是：（1）鸟粪石结晶，（2）鸟粪石结晶与沸石上的N吸附结合，（3）鸟粪石结晶与生物炭上的N吸附结合，（4）不含氮的沸石吸附鸟粪石结晶，以及（5）氮在生物碳上的吸附而没有鸟粪石结晶。

接下来，在作物试验中测试了被污染的鸟粪石吸附剂肥料，其中测量了可食用植物组织（番茄）中药物的生物蓄积性。在所有情况下，发现每种农作物试验中每种掺加肥料的番茄果实生物量中的这种生物累积量均低于0.0003％，远低于可接受的每日摄入量（ADI）水平（每天应食用750公斤干番茄至达到ADI限制）。因此，发现使用尿液衍生的鸟粪石吸附剂种植的番茄果实对人类健康的后续风险微不足道。