Evaluation of the effects of Alkyl Phenolic compounds on kinetic coefficients and biomass activity in MBBR by means of respirometric techniques

The presence of Alkyl Phenols(APs) in aquatic systems is considered as one of the environmental concerns in recent decades which are generally used as surfactants. APs are endocrine disruptors and estrogen-mimicking,causing harmful effects such as feminization and carcinogenesis on aquatic environment and human health.The most commercially important APs are 4-Nonyl Phenol(4-NP) and 4-tert-OctylP henol(4-t-OP). Moving bed biofilm reactor(MBBR), which combined attached and suspended growth advantages, is an advanced biological treatment process for municipal and industrial wastewaters that has drawn considerable attention from many researchers to remove toxic pollutants from wastewater. The aim of this research was to evaluate Bacterial activities and kinetic coefficients in the presence of APs. This study was carried out using laboratory-scale MBBR fed with synthetic wastewater containing 4-NP and 4-t-OP. The reactor was operated at different loads of chemical oxygen demand(COD) and APs and different hydraulic retention time(HRT). The respirometric technique was applied to investigate the effect of APs on heterotrophic and autotrophic activity and kinetic coefficients in biomass obtained from MBBR. Respirometric technique demonstrates a reliable tool in order to assess the biofilm kinetic coefficients and biomass viability to insert in the mathematical models. The calculated kinetic parameters were in the range of conventional and extended aeration activated sludge processes. The results demonstrate that APs have significant inhibitory effects on activity and growth rate of heterotrophic and autotrophic bacteria, heterotrophs have been less affected by the presence of 4-NP and 4-t-OP, and these compounds had greater inhibitory effects on autotrophic bacteria.

Material-Efficient Utilization of Waste Oils—Biodegradability and Other Chemical Properties of Vegetable Recycling Oils

Material efficiency is nowadays an essential topic to promote the sustainable use of natural resources, waste materials and industrial by-products, in agreement with the principle of sustainable development and LCA (life cycle assessment). In this research it was determined the biodegradation of used vegetable oil based products and their important physico- chemical properties for their suitability in different applications such as chain oil in the forestry equipment and mold oil in concrete casting etc. Biodegradability is a measure of the ecological nature of products, and thus from an environ- mental point of view, is the most important evaluated property in this research. As a result, all measured properties of the studied recycled vegetable oils show that the products are environmentally friendly. Two types of vegetable oil were studied;three chain oils and two mold oils. The degree of biodegradation (BOD28) of the mold oils, was about 77 % and the biodegradation of chain oils was about 60% - 62%. In addition, this paper also presents a process outline for manu- facturing recycling vegetable oils.