Economic feasibility of phosphorus recovery through struvite from liquid anaerobic digestate of animal waste.

Although the struvite crystallization process has proven to be an effective process for the recovery of nutrients from wastewater, this process has not been widely used due to the excessive use of chemicals. In this study, the optimal production conditions, yield, and economic feasibility of struvite using the anaerobic digestion of livestock wastewater were investigated. In addition, the economic feasibility of adding zeolite to improve the productivity of struvite and additionally remove nitrogen was evaluated. The result of the experiment on the struvite yield change according to the molar ratios at pH 9.0 showed that the struvite yield ratio was 99.0% of the stoichiometric yield at the Mg2+ :NH4+ :PO43- molar ratios of 1.2:1.0:1.1. As a magnesium source, MgCl2, concentrated seawater in the seawater desalination process, and MgO were compared, and when MgO was used, struvite productivity and economic efficiency were the best. Also, while the addition of zeolite greatly increased the struvite production and zeolite was also sold as a soil conditioner, the struvite sales benefit was estimated to be 103% of the operating cost.

Prevalence of human papillomavirus-related diseases in the Republic of Korea: a cross-sectional study.

OBJECTIVE: We aimed to evaluate trends in the prevalence of human papillomavirus (HPV)-related diseases in the era before the introduction of organised HPV vaccination programmes in the Republic of Korea. METHODS: This cross-sectional study used National Health Insurance Service data from 2002 to 2015 and included participants who were diagnosed with the following HPV-related diseases (codes from the International Classification of Diseases, 10th Revision): genital warts (A63.0); cancer in the head and neck (C00-C10), anus (C21), vulva (C51), vagina (C52), cervix uteri (C53) and penis (C60); carcinoma in situ (CIS) of the lip/oral cavity/pharynx (D00.0), anus (D01.3), cervix (D06), vulva (D07.1), vagina (D07.2) and penis (D07.4); benign neoplasms of the larynx (D14.1); and dysplasia of the cervix (N87), vagina (N89) and vulva (N90). For each diagnosis, the fraction of cases attributable to HPV in Korea was assessed based on the percentages of diseases attributable to HPV reported in some international studies. The age-standardised prevalence was estimated using the direct population-based method. RESULTS: The overall age-standardised prevalence of HPV-related diseases increased from 2002 to 2015, mainly due to increased prevalence of genital warts in men and cervical dysplasia and CIS in women. In women, genital wart prevalence increased from 2002 (24.4 per 100 000) to 2011 (57.1) and then decreased until 2015 (53.5); in men, the prevalence increased steadily from 2002 (22.9) to 2015 (109.4). The prevalence of cervical dysplasia and CIS increased (from 86.5 in 2002 to 484.5 in 2015, and from 60.3 in 2002 to 114.9 in 2015, respectively), but that of cervical cancer decreased (from 120.0 in 2002 to 106.9 in 2015). CONCLUSIONS: Non-organised HPV vaccination and organised cervical cancer screening may have contributed to the downward trend in genital wart prevalence and the upward trend in cervical abnormalities among women.