How Women and Men Pee: Assessing Gender-Specific Urination Practices for a Comfortable Toilet Experience

NoMix toilets separate urine and feces at the source and are a promising resource recovery technology. However, design issues hamper the transformation from unattractive to aspirational products. Little effort has been done to design toilets that account for physiological differences, leading to adverse effects on user-friendliness and urine separation efficiency. We used infrared recordings to assess gender-specific urination practices. Based on field data, we developed the Urinator, a simple device that allows simulating male and female urine streams. This supports engineers in developing more user- and gender-friendly and reuse-oriented sanitation technologies.

Pyrolysis of Dry Toilet Substrate as a Means of Nutrient Recycling in Agricultural Systems: Potential Risks and Benefits

Biochar is increasingly being applied as a soil amendment in agriculture. Biochar is typically produced from plant biomass and contains relatively low amounts of plant nutrients (e.g., N, P, and K), thus providing limited fertilizer value. Human excreta contains plant nutrients that could be recycled to create sustainable agricultural nutrient cycles. This study investigated the potential of biochar derived from a dry toilet substrate as soil amendment. The substrate consisted of urine, faeces, and wood chips, and was pyrolyzed at 500–650 °C for 10 min. The biochar was analyzed for plant available P, water leachable P and K, carbon stability, pH, electrical conductivity, polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), dioxins, and germination tests with barley and lettuce were conducted to estimate the biochar fertilizer value and potential bio-toxicity. The biochar contained 25.0 ± 1.0 g N/kg dry mass (DM), 33.1 ± 2.1 g P/kg DM and 20.7 ± 0.2 g K/kg DM. 65% DM P was extractable by formic acid solution, 31.7% DM P and 60.5% DM K were water leachable in a ten-day column water-leaching experiment. The biochar complied with European regulations for PAHs, PCBs, dioxins and heavy metal concentrations, except for Zn and Ni. Germination of salt-resistant barley was not affected by biochar doses < 50% DM, while salt-sensitive lettuce germination was inhibited at doses ≥ 2% DM, indicating that the dry toilet substrate biochar induced salt stress. Based on these results, it is recommended that urine separation should be considered for biochar of excreta, which could reduce salt stress while maintaining concentrations of “fixed” or bioavailable nitrogen. Graphic Abstract

How does greywater separation impact the operation of conventional wastewater treatment plants?

Source separation has thus far been addressed mainly within the context of decentralization in new development areas; centralized approaches for resource-oriented sanitation remained, however, largely disregarded. By means of inhabitant-specific load and volume flow balances, based on typical reference values for municipal wastewater in Germany, a stepwise transition towards on-site greywater recycling was investigated for a model wastewater treatment plant (WWTP). Up to 17% transition (separation of greywater from 17% of the total inhabitants), greywater separation was proven to benefit plant operation by reducing energy consumption for aeration. From 17% transition onwards, however, unfavorable carbon to nitrogen ratios (C/N) were reported, as less biodegradable carbon reaches denitrification, thus shifting C/N ratios negatively. Therefore, nitrogen recovery/removal from N-rich sludge sidestreams would be required. At 35% transition, a 50% N recovery from sludge liquor was proven to be sufficient in order to ensure full denitrification; combined with greywater separation, nutrient recovery yielded 14% reduction in power demand for aeration (on the actual state). Additionally, extensive mainstream process changeovers could be avoided by separating N-rich urine alongside greywater from the main wastewater stream. Urine separation was proven to maintain denitrification stability as well as reduce power demand for aeration. The calculations show that, under consideration of specific boundary conditions, existing WWTP can be successfully integrated in transition concepts for resource-oriented sanitation.

Salt content of reclaimed water from sanitation facilities in informal settlements and management options for sustainable agricultural irrigation

For long-term sustainable irrigation of agricultural areas, salt accumulation on the fields needs to be controlled. In areas where rainfall is high at least during some time of the year, infiltrating water is usually sufficient to leach salts from the soil. In arid and semi-arid regions, rainfall might be too scarce, and additional measures for the removal of salts from the root zone are necessary. This paper presents data on water quantities, electrical conductivity (EC), and total dissolved solids (TDS) from a research project with agricultural water reuse in North Namibia and discusses options for salinity management. During planning, TDS were quantified using literature data. After implementation, quantities, EC, and TDS of tap water and reclaimed water were monitored. Mean water consumption is 61–64 L per capita equivalent and day. TDS loads are about 20–21 g/(capita equivalent × d) and thus lower than reported in literature. TDS loads in the water can be reduced by measures such as urine separation or reverse osmosis membrane filtration. However, accumulation on the field is still considerable in the long term. Salt uptake in crops is only substantial to the salt balance if TDS contents of the irrigation water are relatively low. Therefore, in the majority of cases, regular drainage and leaching of the fields are necessary. The per capita TDS loads and water quantities presented in this work are specific results collected from the facilities implemented in this project. They can serve as a basis for estimating water quantities and excreta loads for similarly managed sanitation facilities.

Combined seawater toilet flushing and urine separation for economic phosphorus recovery and nitrogen removal: a laboratory-scale trial

Freshwater toilet flushing consumes 20–35% of typical household water demand. Seawater toilet flushing, as practised by Hong Kong since 1958, provides an alternative water source. To maximise the benefits of this unique dual water supply, urine separation could be combined to allow low-cost struvite production and subsequent urine nitrification – in-sewer denitrification. This paper reports on a laboratory-scale study of seawater urine phosphate recovery (SUPR) and seawater–urine nitrification. A laboratory-scale SUPR reactor was run under three phases with hydraulic retention time between 1.5 and 6 h, achieving 91–96% phosphorus recovery. A urine nitrification sequencing batch reactor (UNSBR) was also run for a period of over 650 days, averaging 90% ammonia removal and loading of up to 750 mg-N/L.d. Careful control of the SUPR phosphate removal was found necessary for operation of the downstream UNSBR, and system integration considerations are discussed.

A Novel HPLC Method for the Concurrent Analysis and Quantitation of Seven Water-Soluble Vitamins in Biological Fluids (Plasma and Urine): A Validation Study and Application

An HPLC method was developed and validated for the concurrent detection and quantitation of seven water-soluble vitamins (C, B1, B2, B5, B6, B9, B12) in biological matrices (plasma and urine). Separation was achieved at 30°C on a reversed-phase C18-A column using combined isocratic and linear gradient elution with a mobile phase consisting of 0.01% TFA aqueous and 100% methanol. Total run time was 35 minutes. Detection was performed with diode array set at 280 nm. Each vitamin was quantitatively determined at its maximum wavelength. Spectral comparison was used for peak identification in real samples (24 plasma and urine samples from abstinent alcohol-dependent males). Interday and intraday precision were <4% and <7%, respectively, for all vitamins. Recovery percentages ranged from 93% to 100%.

Modelling anaerobic digestion of concentrated black water and faecal matter in accumulation system

A dynamic mathematical model based on anaerobic digestion model no. 1 (ADM1) was developed for accumulation (AC) system treating concentrated black water and faecal matter at different temperatures. The AC system was investigated for the treatment of waste(water) produced from the following systems: vacuum toilet for black water (VBW), vacuum toilet for faeces with urine separation (VF), dry toilet (DT), dry toilets for faeces with urine separation (DF), separated faecal matter from conventional black water by filter bag (FB). For evaluation of the AC system treating the proposed waste(water) sources at 20 and 35°C, two options were studied: (1) The filling period of the AC system was constant for all waste(water) sources (either 1, 3 or 6 months) and for each period, the seed sludge volume was varied; (2) The volume of the AC system was constant for all proposed waste(water) sources. The results showed that the filling period of the AC system was the main parameter affecting the system performance, followed by operational temperature, while the increase of the seed sludge volume slightly enhanced the performance of the system. The model results indicated that the filling period of the AC system should be higher than 150 days for obtaining a stable performance. It was found that the hydrolysis of biodegradable particulate chemical oxygen demand (COD) is the rate limiting step, as volatile fatty acid concentration is very low in all experimental conditions (&lt;200 mgCOD/L at 20 °C and &lt;100 mgCOD/L at 35 °C). Based on the results of the two options, it was found that the concentrated waste(water) sources have better performance than the diluted waste(water) sources, like VBW waste(water). Furthermore, smaller volume will be required for the AC system.

PENGARUH BEBAN TEKAN TERHADAP KEMAMPUAN EKSTRAKSI MASSA CAIR SLURRY OLEH “ALAT PEMISAH FASES-URINE SAPI” YANG DIOPERASIKAN SECARA MANUAL

Cow manure can be used as a source of energy and as a solid or liquid fertilizer. An adult cow can produce fases (solid manure) to 23 kg/day and urine (liquid manure) 9 kg/day. Three or four cow is capable to fullfill the dayly needs of cooking fuel for one rural household. Cow manure slurry can also be convert as fertilizer, that is liquid fertilizer which is derived from urine and solid fertilizer originating from the solids. Solid and liquid from cow manure is usually mixed, therefore to make the liquid and solid fertilizer, the liquid and solid masses need to be separated first. Recent separators of fases and urine are are electrical energy driven, so that those kind of device could not be used in the rural areas where the electric grid supply were not available. So that a model of a faces-urine separator of cow manure slurry is utilize which was constructed for manual pressing force. Moreover, through this research It have had created a manual fases-urine separator which only requires one operator. The separator consists of main parts including; lever press, chamber press, fases-urine separation mechanism, the mechanism of loading-unloading, and ajustment mechanism for pressing pressure. This design is capable of performing the separation in a wide range of pressing force and it only requires one operator. Results Show That the model is capable to separate liquid from the slurry as much as 13.9% at a pressing force of 14 kg the which is applied for 18 seconds.