Screening of Polyphosphate Accumulating Organisms and Their Phosphorus Removal Performance

[Objectives]To study the phosphorus removal performance of phosphate accumulating organisms(PAOs).[Methods]Activated sludge from domestic sewage treatment plant was used as the strain source,and phosphate accumulating organisms were screened by plate streaking method and dilution coating plate method.Six kinds of excellent phosphate accumulating organisms were obtained by metachromatic granule staining experiment,total phosphorus experiment and simulated sewage phosphorus removal experiment to assist the observation of bac-terial morphology and experiment of phosphorus removal capacity.In addition,the influencing factors of phosphorus removal capacity(nitrogen source,trace metal ions)were analyzed.[Results]In the case of simulated sewage,the phosphorus removal rate of strain b was the highest,reaching 66.25%,while the phosphorus removal rate of strain e and f was about 10%lower than that of the phosphorus uptake experiment.[Conclusions]This study is expected to provide a theoretical reference for the gradual optimization of the screening method of phosphorus re-moval bacteria in domestic sewage treatment.

Development and validation of the Nurse’s Workplace Mental Health Questionnaire

Objectives:This study aimed to develop and validate the Nurse’sWorkplace Mental Health Questionnaire(NWMHQ).Methods:The questionnaire was developed based on the two continua model of mental illness and health proposed by Keyes.The initial questionnaire was generated through literature review,two rounds of Delphi expert consultation,followed by a pilot survey.Finally,the reliability and validity of the questionnaire were validated through an online survey of 2,815 registered nurses selected from the public hospitals in 11 provinces from June to July 2020.Results:The item-content validity index(I-CVI)of the questionnaire ranged from 0.750 to 1.000 and the average scale-level content validity index(S-CVI/Ave)was 0.906.Cronbach’s a coefficient was 0.948 and test-retest reliability was 0.850.The self-rating depression scale score was negatively related to the NWMHQ score(r=0.664,P<0.01).The exploratory factor analysis(EFA)yielded six factors(emotional status,psychological security,positive relationship,resilience,self-efficacy,and subjective well-being),consisting of 32 items.The cumulative variance contribution rate was 65.58%.Confirmatory factor analysis(CFA)showed an acceptable fit.Conclusion:The NWMHQ developed in this study showed good reliability and validity.This questionnaire may help assess the mental health status of nurses and help nursing managers to develop appropriate targeted psychological interventions.