Tjaša Griessler Bulc

Removal of particles in organic filters in experimental treatment systems for domestic wastewater and black water

This study assesses the total suspended solids (TSS) retention capacity of different organic filter media for two potential applications: (i) a polishing unit for package treatment plants and (ii) a pretreatment for blackwater from low‐flushing toilets. The results showed that the peat filter media used can be significantly improved in terms of structural stability and TSS removal capacity by mixing it with sawdust. Most of the TSS accumulated in the upper part of the filter material, and filter thickness exceeding 15 cm had no statistically significant effect (P < 0.1) on the TSS treatment performance. The experimental system reached a TSS reduction of 60–70% for blackwater and 80–90% for simulated effluent peaks from a package treatment plant. The main challenge of a full‐scale application of an organic filter is the issue of clogging, especially when treating concentrated blackwater. However, this work indicates that a clogged filter media can be regenerated by mixing the uppermost filter layer without significant loss of filter performance regarding TSS. More research is needed to develop an appropriate mechanical unit for automatic filter media regeneration.

Ecosystem Technologies and Ecoremediation for Water Protection, Treatment and Reuse

Despite the access to safe drinking and sanitary water, which is a precondition for human health and well-being, water quality is still seriously threatened by point and non-point sources of pollution, originating mostly from urban and rural areas. Due to rapid development, the problems associated with urbanization do not delay to appear: water scarcity, food insecurity and pollution (Esrey, 2000). Most people in Europe do have access to drinking water of good quality, but on the other hand there are one billion people worldwide with limited or no access to uncontaminated water (Jenssen et al., 2004). Conventional sewer systems use considerable amounts of valuable drinking water for flushing and transporting toilet waste. In the processes, huge amounts of fresh water, up to 50,000 liters per year per person, are contaminated and deemed unfit for other purposes. A massive flow of nutrients, drained from rural and urban areas, mixes with fresh waters. These nutrients take the form of excreta and are usually disposed into deep lakes or pits, rivers, and coastal waters. The excreta are toxic for many forms of aquatic life (e.g. fish and coral reefs), they cause eutrophication, reduce biodiversity, affect human health and soil quality (Esrey, 2000). Accretion of excreta also causes accumulation and release of toxic substances like heavy metals and micro-pollutants. On the other hand, research findings show that the world’s reserves of commercial phosphate will exhaust in fifty to hundred years and, as predicted, the production of phosphorus will reach its peak around 2030 (Cordell et al., 2009). It is obvious that wrong flow of nutrients causes the loss of soil fertility and unnecessary water pollution at the same time.