Sludge recycling as an agricultural resource has gained great attention worldwide. This is exacerbated by the ever-rising municipal wastewater production and the realization of its potential as a soil amendment resource. Sludge suitability assessment and characterization is crucial to prompt informed decisions regarding its use on agricultural lands. Liquid sludge samples were collected from eighteen wastewater treatment plants (WWTPs) employing three different treatment processes in South Africa. Samples were analysed for physical and chemical parameters. Sludges’ pH ranged from 4.5-9.5. Heavy metals concentrations were below the threshold level except for two waste activated sludge (WAS) which were downgraded to class B due to high Lead (Pb) content. Two anaerobically digested (AnD) sludges were downgraded to classes B and C because of high Pb and Cadmium (Cd) concentrations respectively. Electrical conductivity (EC) was above the 200 mS m threshold in AnD and in one of aerobically digested (AeD) sludges whilst WAS had ≤100 mS m. Nitrogen (N): Phosphorus (P) ratios of the sludges were <8. Application of biosolids with low N:P ratio based on crop N requirements would lead to P pollution. Sustainable sludge application options were either to apply dry sludge based on crop N or P requirements and supplement the nutrient deficit with other fertilizer sources. The use of current liquid sludge as irrigation water to meet crop water needs and or applying dry sludge at 10 tons ha options showed that such options are unsustainable and would add excess nutrients above crop need which would result in agroecosystems pollution. The study findings suggest that, supposedly these liquid sludges are used for irrigation, they should be diluted with fresh water or deficit irrigation should be implemented to limit nutrient load.Copyright © 2020 Elsevier B.V. All rights reserved.
Correlation of clinical outcome, radiobiological modeling of tumor control, normal tissue complication probability in lung cancer patients treated with SBRT using Monte Carlo calculation algorithm.
August 17, 2020
Association between Adult Attention Deficit/Hyperactivity Disorder and Intravenous Misuse of Opioid and Benzodiazepine in Patients under Opioid Maintenance Treatment: A Cross-Sectional Multicentre Study.
January 30, 2020
[Age identity disorders (infantilism/ puerilism) in the psychopathological space of endogenous diseases].
February 28, 2020
- ACC 2020The American College of Cardiology decided to cancel ACC.20/WCC due to COVID-19, which was scheduled to take place March 28-30 in Chicago. However, ACC.20/WCC Virtual Meeting continues to release cutting edge science and practice changing updates for cardiovascular professionals on demand and free through June 2020.
Psych Congress 2019The annual Psych Congress, held in San Diego, California, from October 3-6, 2019, brings together members of the entire mental health team, including psychiatrists, physician assistants, nurse practitioners, psychologists, and primary care physicians, with experts in mental health to improve patient outcomes through education.