The performance and potential of faecal separation and urine diversion to recycle plant nutrients in household wastewater

In household wastewater and biodegradable solid waste, the main proportion of the plant nutrients are found in the toilet water (i.e. in urine and faeces). In order to recover most of these nutrients, with the purpose of decreasing the emission of eutrophicating agents and of increasing their recycling, present waste and wastewater systems have to be changed. If the urine and the faeces are collected, up to 91%, 83%, and 59% for N, P and K, respectively, can be recovered and recycled from the household wastewater. The urine was collected separately in a double flushed urine-diverting toilet and the faeces were separated from the flushwater using two parallel Aquatrons. The Aquatron separates by a combination of a whirlpool effect, gravitation and surface tension. In this study, nitrogen and phosphorus from the faeces were separated to 73% and 58%, respectively, to the dryer fraction. The combination of faecal separation and urine diversion in the house Ekoporten made it possible to collect 60% of N, 46% of P and 43% of K from the wastewater, indicating that this method is an alternative when aiming to recover plant nutrients while still wanting to use water-flushed, urine-diverting toilets, though the potential to collect the nutrients is much higher.     

Ancient Human Genomes and Environmental DNA from the Cement Attaching 2,000-Year-Old Head Lice Nits

Over the past few decades, there has been a growing demand for genome analysis of ancient human remains. Destructive sampling is increasingly difficult to obtain for ethical reasons, and standard methods of breaking the skull to access the petrous bone or sampling remaining teeth are often forbidden for curatorial reasons. However, most ancient humans carried head lice and their eggs abound in historical hair specimens. Here we show that host DNA is protected by the cement that glues head lice nits to the hair of ancient Argentinian mummies, 1,500–2,000 years old. The genetic affinities deciphered from genome-wide analyses of this DNA inform that this population migrated from north-west Amazonia to the Andes of central-west Argentina; a result confirmed using the mitochondria of the host lice. The cement preserves ancient environmental DNA of the skin, including the earliest recorded case of Merkel cell polyomavirus. We found that the percentage of human DNA obtained from nit cement equals human DNA obtained from the tooth, yield 2-fold compared with a petrous bone, and 4-fold to a bloodmeal of adult lice a millennium younger. In metric studies of sheaths, the length of the cement negatively correlates with the age of the specimens, whereas hair linear distance between nit and scalp informs about the environmental conditions at the time before death. Ectoparasitic lice sheaths can offer an alternative, nondestructive source of high-quality ancient DNA from a variety of host taxa where bones and teeth are not available and reveal complementary details of their history.     

A comparison in product‐value potential in four treatment strategies for food waste and faeces – assessing composting,fly larvae composting and anaerobic digestion

Municipalities are expected to provide solid waste management, which is funded by tax revenue or/and waste treatment fees. In many low‐ and middle‐income countries, municipalities struggle to provide an adequate level of service, and in these places, the informal sector plays a major role in the collection and treatment of solid waste. In contrast to the plastic and metal fraction, the organic fraction is not managed by the informal sector, primarily because it has low or no financial value and treatment would cost more than the possible revenue. If the organic fraction could be converted to valuable products, the treatment could bear its own cost and this could act as an incentive to collect and treat this fraction. In this study, the potential product value generated through four treatment strategies treating food waste and faeces was compared in a Swedish context: (i) thermophilic composting; (ii) black soldier fly treatment (BSF treatment); (iii) anaerobic digestion (AD); and (iv) BSF treatment followed by AD (BSF + AD). In order to assess the AD strategies, the biomethane potentials of the substrates were assessed. Food waste had the highest biomethane potential, while BSF‐treated faeces had the lowest (417 and 188 NmL g VS^?1, respectively). Thermophilic composting yielded the lowest value product (organic fertilizer; 26 € t^?1 treated food waste) and BSF treatment + AD the highest total value of products (animal feed, vehicle gas and organic fertilizer; 215 € t^?1 treated food waste). The treatment costs were not taken into account here; the total value gives an indication of the cost margin for the different strategies studied. In places with an existing AD plant, BSF treatment + AD strategy is the most economically viable. In places where no such plant exists, BSF treatment is likely to be the most economically favourable treatment.     

Environmental genomics of Late Pleistocene black bears and giant short-faced bears

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Thermal composting of faecal matter as treatment and possible disinfection method--laboratory-scale and pilot-scale studies

When using toilets where the urine and faeces are collected separately for reuse as nutrients in agriculture, the collected matter should be disinfected. One way to do this is by thermal composting. Composting of different material mixes was investigated in a laboratory-scale experiment. This showed that the best mixture for dry thermal composting was a mix of faeces, food waste and amendment. The urine was collected separately by use of urine-diverting toilets. A new method was developed to mathematically evaluate and estimate the safety margins of pathogen inactivation during thermal composting. The method is based upon a mathematical calculation of the number of times total inactivation (at least 12log(10) reduction) of the organisms is achieved. In a pilot-scale experiment, the disinfection of a faeces/food waste mix was performed with a calculated safety margin of more than 37 times the total die-off of Enteroviruses and some 550 times that of Ascaris. Thus, well functioning composting seems to be effective for disinfection of faecal matter. To get a high temperature in all of the material, the reactor has to have sufficient insulation. A major disadvantage is the initial need for handling the raw un-disinfected material. The degradation of the organic matter in the compost was almost 75%, resulting in a small final volume that could safely be recycled.