The origin of waste activated sludge affects the enhancement of anaerobic digestion by free nitrous acid pre-treatment.

Anaerobic digestion is a common stabilization method for treating primary sludge (PS) and waste activated sludge (WAS). However, its application is often limited by the degradation of WAS. Recent studies have demonstrated FNA to be an effective pre-treatment for enhancing WAS degradability, while having limited effect on PS degradability. WAS characteristics are impacted by wastewater treatment plant (WWTP) configuration and this study is the first to compare the effectiveness of FNA pre-treatment on WAS from WWTP with and without primary treatment. In this study, WAS samples were collected from four full-scale WWTPs with or without primary treatment. Sludge characterization, biomethane potential tests and mathematical modeling were conducted to assess the impacts of FNA pre-treatment on anaerobic digestion. The results showed that FNA pre-treatment was consistently effective for WAS from different WWTPs, while the extent of enhancement varied between WWTPs. For WAS from WWTPs without primary treatment, FNA pretreatment increased the rate of hydrolysis by 54-66% compared to 22-33% increase for WAS without primary treatment. In contrast, WAS from WWTPs with primary treatment experienced greater increases in methane potential (22-24%) compared to WAS from WWTPs without primary treatment (14-16%). These variances could be associated with primary treatment impacting the wastewater COD/N ratio and thus portion of extracellular polymetric substances (EPS) and cells in WAS. FNA pre-treatment targets the destruction of polymetric substances and cells, therefore WAS with a higher proportion of cells (i.e., WAS with primary treatment) experienced greater improvements in methane yield. Similarly, greater improvements in hydrolysis rate were observed for WAS from WWTP without primary sedimentation which contain higher proportions of large EPS molecules. Despite its consistent effectiveness on WAS samples, FNA pre-treatment was ineffective for improving the digestibility of high-rate activated sludge (HRAS).

Benefits and drawbacks of food and dairy waste co-digestion at a high organic loading rate: A Moosburg WWTP case study.

Anaerobic co-digestion (AcoD) is a key technology in reframing organic waste as a viable energy source. A lack of documented experience on full-scale AcoD at wastewater treatment plants (WWTPs) has created a bottleneck in AcoD implementation, which is further tightened by the focus of existing AcoD studies being on low co-substrate loading (<50%) and the obtainable benefits. This study aims to fill this gap by investigating the drawbacks and benefits of high-ratio co-substrate dosing of food and dairy wastes at the Moosburg WWTP (Germany) from 2014 to 2017. The Moosburg WWTP co-digests sewage sludge, food waste, and dairy wastes at a 35:47:18 ratio by volatile solids (organic loading rate (OLR) of 3.0 kgVS/(m3·day)). During the study period, this high co-substrate dosing increased the methane potential by 300 ±â€¯50%. The corresponding high methane yield significantly increased the on-site electricity production, resulting in energy neutrality in 2014-2015. The corresponding economic gain from gate fees was 48,000 ±â€¯5,000 € per year. The observed drawbacks included solids accumulation inside the digester (5 m3/month), high nitrogen backload (65% increase from co-substrate addition), reduced retention time (loss of 1.18 days/year from solids accumulation), and reduced dewaterability. The high nitrogen content in the centrate is treated by sequential batch reactors (SBRs), using lactose as the carbon source for denitrification. This study presents an alternative approach for determining gate fees based on the economic gains from inherent methane content, which identified waste milk, lactose and grease trap sludge as the most profitable co-substrates.

Differentiation of prostate epithelial cell cultures by matrigel/ stromal cell glandular reconstruction.

Three-dimensional epithelial culture models are widely used to emulate a more physiologically relevant microenvironment for the study of genes and signaling pathways. Prostate epithelial cells can grow into solid cell masses or acinus-like spheroids in Matrigel. To test if the ability to form acinus-like spheroids in Matrigel is dependent on how undifferentiated a cell is or whether it is tumor or nontumor, we established six novel epithelial cell lines. Primary prostate epithelial cells were immortalized using HPV16 E6 gene transduction and were named Shmac 2, 3, and 6 (nontumor); Shmac 4, Shmac 5, and P4E6 (tumor). All cell lines were phenotyped in monolayer culture, and their ability to form acinus-like spheroids in Matrigel investigated. The cell lines exhibited a wide range of population doubling times and all showed an intermediate phenotype in monolayer culture ((luminal)CK(+)/(basal)CK(+)/CD44(+)/PSA(+)/AR(-)). Only Shmac 5 cells formed acinus-like spheroids when cultured in Matrigel. Co-culture of the spheroids with fibroblasts advanced differentiation by inducing androgen receptor expression and epithelial polarization. Our findings indicate that tumor cells can form acinus-like spheroids in Matrigel.