Effect of phosphate and ammonium concentrations, total suspended solids and alkalinity on lignin-induced struvite precipitation.

To solve the problems of eutrophication and resource crisis, the recovery of phosphorus by struvite (NH4MgPO4·6H2O) precipitation has become a focus of recent research. The feasibility of using Kraft lignin powder as a seed to promote struvite precipitation has been demonstrated in the previous study. In this study, the effect of lignin in promoting struvite precipitation in synthetic wastewater with different characteristics was investigated. Lignin-induced struvite crystallization was tested under various initial concentrations of PO4-P and NH4-N, total suspended solids (TSS) and alkalinity. At pH 7.9, the enhancement of PO4-P recovery remains around 45% under different PO4-P and NH4-N concentrations. Moreover, lignin is more effective under relatively lower alkalinity and still workable to reduce co-precipitates potential under higher alkalinity. Also, the effect of TSS on PO4-P recovery is not significant. Overall, the effect of lignin in promoting phosphorus recovery is relatively stable and can be used in synthetic wastewater with different characteristics.

Rare presentation of multisystem inflammatory syndrome in an adult associated with SARS-CoV-2 infection: unilateral neck swelling.

Multisystem inflammatory syndrome in adults (MIS-A) is a rare but often severe complication of SARS-CoV-2 infection. While several case reports about MIS-A in the setting of COVID-19 have been published since the term was first coined in June 2020, a clear description of the underlying pathophysiology and guideline-based recommendations on the diagnostic and therapeutic approach are lacking. What has been reported is that in the absence of severe respiratory illness, MIS-A can present with hypotension or shock, high-grade fever, abdominal pain, diarrhoea and severe weakness days to weeks after SARS-CoV-2 infection. Here, we present a case of a 28-year-old man who presented with a rarely described initial symptom: unilateral neck swelling. His presentation, disease progression and treatment course provide further information about MIS-A as a complication and in formulating diagnostic guidelines.

Superior vena cava stenosis presenting with bendopnea.

Bendopnea, or dyspnoea with bending forward, is a recently described symptom of heart failure that is associated with elevated ventricular filling pressures. Here, we describe a case of superior vena cava (SVC) stenosis that presented with bendopnea and resolved with SVC recanalisation. We suggest that SVC stenosis be considered in the differential diagnosis of patients who experience bendopnea.