The West Indies have during recent years been experiencing large quantities of washed up Sargassum seaweed on beaches and coastlines causing many issues for local communities such as unpleasant odours, making beaches inaccessible and largely affecting tourism and fisheries. The issue has caused money loss for the communities both in cleaning costs and decreasing incomes from tourism and fishing. In an attempt to turn this destructive debris into a useful resource, this study aimed to determine the potential for Sargassum that has been anaerobically digested to be used as a liquid fertiliser on Grenada. Sargassum seaweed was collected from the Atlantic coast of Grenada and transported and fed to a biogas plant where the algae was anaerobically digested. The residues were collected and fed to Pak Choi crops in a cultivation experiment where the fertiliser was compared with other treatment methods in order to determine its efficiency as a fertiliser. Interviews of farmers on Grenada were also conducted during the project to examine the potential and usefulness of the biofertiliser on the local Grenada farms. It was found that the digestate product from the anaerobic digestion showed good potential as a biofertiliser, producing larger and healthier crops than the other methods of treatments, among them artificial fertiliser. A potential market for the product was also identified as all the interview subjects reported that artificial fertilisers can be hard or impossible to find on Grenada sometimes of the year, due to the island's high reliance on shipping containers for import, leading to a demand of alternative fertilisers. / Under de senaste åren har algblomningarna ökat runt om i Västindien och numera är flertalet stränder  fyllda av Sargassotång. Ett av länderna som har påverkats negativt är Grenada. Stora mängder Sargassum når östkusten av Grenada under större delen av året till skillnad från tidigare år då algerna enbart sköljdes in under vissa perioder och i mindre kvantiteter. Algmassorna leder till lokal övergödning i de drabbade områdena, vilket i sin tur leder till minskad syrekoncentration i vattnet och en stor påverkan på djur och växter i ekosystemet. I Grenada påverkar makroalgerna även inkomstkällan för fiskare då de inte kan arbeta när det är som mest alger eftersom båtarna inte kan ta sig förbi massorna i vattnet. Även lokalbefolkning och turister påverkas då nedbrytningen av algerna skapar en motbjudande lukt vilket leder till att människor flyttar från dessa områden och att turistnäringen minskar. Grenada har ett behov av att minska mängden alger längs stränderna och samtidigt finns en möjlighet att ta tillvara en lokal bioresurs. En möjlighet är att använda algmassan till produktion av biogas och biogödningsmedel eftersom nedbrytning av makroalgeralger både kan producera metangas samt att  återstående restbiomassa innehåller de viktigaste näringsämnen som växter behöver för att växa. Därför  har algerna använts i ett försök på True Blue Bay Boutique Resorts anläggning på Grenada för att producera biogas och gödsel med hjälp av en mindre biogasanläggning. Anläggningen matas med biomassa och därefter har en gas och en restprodukt producerats. Restprodukten har därefter används som gödningsmedel i ett odlingsförsök med Pak Choi för att fastlägga dess kvalitet som växtnäring. Plantor gödslades med restprodukter från biogasanläggningen, både när anläggningen matats med grisgödsel och hushållskompost i början samt när födan successivt övergick till alger. Andra plantor fick konstgödsel eller färska alger. Utöver det fanns det en grupp med plantor vilka inte tog del av någon form av gödsel för att fungera som en kontrollgrupp. Vid slutet av odlingsförsöket skördades Pak Choi grödorna och produktivitet och kvalitet på grödorna bedömdes baserat på olika kriterier. Resultaten visade att de växter som blivit gödslade med resterna från biogasanläggningen var störst och av bäst kvalitet. Därutöver har en undersökning genomförts för att få en större förståelse för hur tillgången på alger ser ut och för att få en bild över hur lantbrukares behov av gödningsmedel ser ut på Grenada. Lantbrukare har tillfrågats om tillgång och efterfrågan på olika sorters gödsel, hur de använts och om de har några erfarenheter från Sargassotång. Deras åsikter har varierat, men en gemensam nämnare är att alla är intresserade av lokalproducerade gödningsmedel. Konstgödsel är kostsamt och det kan vara svårt eller omöjligt att få tag på under vissa delar av året, då landet förlitar sig på import. Genom detta har en potentiell marknad för gödselmedel producerat med alger fastställts.

Nachhaltige Landbewirtschaftung impliziert ausgeglichene Pflanzennährstoffflüsse ohne die Abhängigkeit von Düngern aus nicht erneuerbaren Quellen. Stickstoff, Phosphor und Kalium aus der menschlichen Nahrung werden in Mitteleuropa im Allgemeinen in Schwemmkanalisationen gesammelt und dabei mit Schadstoffen vermengt. Neuartige stoffstromtrennende Sanitärsysteme ermöglichen die Bereitstellung von Humanurin und Fäkalien zur Verwendung als Düngemittel. In der vorliegenden Arbeit wurden praxisrelevante Aspekte der Verwendung von Düngemitteln anthropogener Herkunft untersucht. Die in Gefäß- und Feldversuchen in Berlin Dahlem ermittelte Ertragswirkung zeigte, dass Urin in dieser Hinsicht äquivalenten Mineraldüngern grundsätzlich gleichwertig ist. Bei sehr hohen Konzentrationen kam es abhängig von der Pflanzenart zu Depressionseffekten, welche vermutlich auf den Salz- und Ammoniumgehalt von Urin zurückzuführen sind. Unter Freilandbedingungen traten diese Effekte nicht auf. Bodenbiologische Auswirkungen von Düngerapplikationen sind entscheidend für die Abschätzung ihrer langfristigen Bodenfruchtbarkeitserhaltung. Sowohl in Labor-versuchen als auch im Freiland zeigten sich Regenwürmer durch menschlichen Urin aus Trenntoiletten deutlich beeinträchtigt. Die Ursache der Schädigung konnte nicht geklärt werden. Von einer langfristigen bodenfruchtbarkeitsreduzierenden Beein-trächtigung wird jedoch nicht ausgegangen. Mikrobielle Enzymaktivitäten im Boden wurden im Freiland durch Urinapplikation nicht beeinflusst. Für die Praxis wird empfohlen Urin während der Ausbringung einzuarbeiten, da die Tiere dann weniger mit der Flüssigkeit in Kontakt kommen. Da es ein umweltpolitisches Ziel ist, die Ammoniakemissionen der Landwirtschaft zu minimieren, wurden diese nach der Urinausbringung im Freiland gemessen. Auf Grund der sehr geringen Trockensubstanzgehalte von Humanurin emittierte deutlich weniger NH3 als üblicherweise nach Ausbringung von Schweine- oder Rindergülle. Verbraucherumfragen bestätigten eine hohe Bereitschaft pflanzliche Nahrung, welche mit Urin als Dünger erzeugt wurde, zu kaufen und zu verzehren. Praktizierende Landwirte reagierten dagegen deutlich reservierter. Die Ausbringung von Urin aus Trenntoiletten kann im Sinne einer nachhaltigen Landwirtschaft grundsätzlich empfohlen werden. Es besteht aber weiterer Forschungsbedarf. / Sustainable agriculture implies balanced nutrient flows and independence from fertiliser made from non renewable resources. In Europe, plant nutrients excreted by humans are commonly collected in water borne sewage systems and thus mixed with potentially harmful substances. Novel segregating sanitation techniques can collect separated urine and faeces in a form which enables their use as fertiliser. In the presented thesis selected aspects concerning the use of anthropogenic plant nutrients relevant to farming were investigated. Pot and field experiments indicated that equal yields can be gained if urine instead of mineral fertiliser is applied. Very high concentrations of urine led to reduced growth, presumably caused by the presence of ammonium or salt. However, this was not found under field conditions. Soil biological effects caused by the application of a fertiliser must be considered when assessing its long term contribution to soil fertility. Laboratory experiments as well as field investigations showed that human urine application severely affects earthworms, however, the harmful components were not identified. The results suggest that the effect is of short term only. Soil microbial enzyme activities were not influenced by urine fertiliser. For farming practice it is recommended to inject or incorporate urine to prevent earthworms from coming into direct contact with the infiltrating fertiliser. Gaseous ammonia loss was measured after urine application on fields as reducing harmful emissions from agriculture is a goal of European environmental policy. Because of the very low Dry Matter contents of urine, far less ammonia was emitted to the atmosphere than usually occurs after application of cattle or pig slurry. A consumer acceptance study showed a general high public willingness to accept urine as fertiliser even if used on crops for food production. The reaction of farmers was mainly reserved as a result of the present legal regulations in Germany. Within the context of sustainable agriculture the use of human urine as fertiliser can be recommended. Further research is necessary, especially concerning any effects resulting from residues of pharmaceutical substances contained in human excreta.

Soil organic matter is important as storage for carbon and nutrients, supporting soil structure, and as a filter for pollutants entering the soil ecosystem. The recovery of soil organic matter in depleted soils can take decades, or even hundreds of years. It has been assumed that in non-eroding pasture, soil carbon levels either increase or not change over time. However, some recent studies have suggested that fertiliser addition to pasture soils may contribute to decreases in soil carbon content. My hypotheses were: 1. As P fertiliser loadings increase the soil carbon content and C:N ratio will decrease. 2. Changes in C pools will be greater in the more active pool (readily available carbon, and microbial biomass carbon) within the soil total carbon The study was undertaken at a long term fertiliser trial, established in 1980, at the Whatawhata Hill Country Research Station west of Hamilton, New Zealand. The fertiliser trial has P fertiliser application rates maintained since 1984. Olsen P, total C, total N, labile carbon, respirable carbon, specific respiration rate, microbial biomass C, microbial quotient, mineralised N, microbial biomass N, microbial N quotient, and mineralised N per microbial biomass nitrogen, C:N ratio, and soil pH were measured on soil samples collected from 12 paddocks with six P fertiliser loading (0, 10, 20, 30, 50, 100 kg P ha-1 yr-1). As expected, the available P (Olsen P) increased significantly (P less than 0.001) with increasing P fertiliser application rate. Total carbon, labile carbon, and total nitrogen all decreased significantly (P less than 0.05) with increasing P fertiliser application. No significant relationships were found between P fertiliser and respirable carbon, microbial carbon, microbial (C) quotient, microbial specific respiration, microbial nitrogen, microbial (N) quotient, mineralised N, or C:N ratio. The first hypothesis was rejected as the C:N ratio did not change with increased P fertiliser application. However, both C and N decreased with increased P fertiliser application. The second hypothesis was, therefore, accepted in part because there was a decrease in labile carbon (readily available carbon) and total carbon, with P fertiliser application, but no relationship was evident for the respirable carbon and microbial biomass.

Human excreta contain plant nutrients and have the potentialto be used as a fertiliser in agriculture. Urine contributesthe major proportion of the nutrients (N, P and K) in domesticwastewater whereas faeces contribute a smaller amount andinvolves greater health risks if reused due to the possiblepresence of enteric pathogens. Human urine does not generallycontain pathogens that can be transmitted through theenvironment. Source-separation of urine and faeces is possible by usingurine-separating (or urine-diverting) toilets, available assimple dry toilets or porcelain flush toilets with dividedbowls. The risk for transmission of disease when handling andreusing the urine is largely dependent on thecross-contamination by faeces. In this research, the presenceof human faeces in urine samples was successfully determined byanalysing for faecal sterols. Cross-contamination was evidentin 22% of the samples from urine collection tanks, and in thesequantified to an average (± SD) of 9.1 ± 5.6 mgfaeces per litre urine. Testing for indicator bacteria wasshown to be an unsuitable method for determining faecalcontamination in human urine sinceE. colihad a rapid inactivation in the urine and faecalstreptococci were found to grow within the system. The fate of any enteric pathogens present in urine iscrucial for the risk for transmission of infectious diseases.Gram-negative bacteria (e.g.SalmonellaandE. coli) were rapidly inactivated (time for 90%reduction, T90&lt;5 days) in source-separated urine at itsnatural pH-value of 9. Gram-positive faecal streptococci weremore persistent with a T90of approximately 30 days. Clostridia sporenumbers were not reduced at all during 80 days. Similarly,rhesusrotavirus andSalmonella typhimuriumphage 28B were not inactivated inurine at low temperature (5°C), whereas at 20°C theirT90-values were 35 and 71 days, respectively.Cryptosporidiumoocysts were less persistent with a T90of 29 days at 4°C. Factors that affect thepersistence of microorganisms in source-separated human urineinclude temperature, pH, dilution and presence of ammonia. By using Quantitative Microbial Risk Assessment (QMRA), therisks for bacterial and protozoan infections related tohandling and reuse of urine were calculated to be&lt;10-3for all exposure routes independent of the urinestorage time and temperature evaluated. The risk for viralinfection was higher, calculated at 0.56 for accidentalingestion of 1 ml of unstored urine. If the urine was stored at20°C for 6 months the risk for viral infection was reducedto 5.4 × 10-4. By following recommendations for storage and reuse, whichare dependent on the type of crop to be fertilised, it ispossible to significantly decrease the risk for infections. Sofar, the level of risk that is acceptable is unknown. Theacceptable risk will be one of the main factors determining thefuture utilisation of source-separated human urine inagriculture. <b>Keywords:</b>urine-separation, urine, wastewater systems,wastewater reuse, recycling, enteric pathogens, faecal sterols,indicator bacteria, hygiene risks, microbial persistence,microbial risk assessment, QMRA, fertiliser, crop.

<p>Human excreta contain plant nutrients and have the potentialto be used as a fertiliser in agriculture. Urine contributesthe major proportion of the nutrients (N, P and K) in domesticwastewater whereas faeces contribute a smaller amount andinvolves greater health risks if reused due to the possiblepresence of enteric pathogens. Human urine does not generallycontain pathogens that can be transmitted through theenvironment.</p><p>Source-separation of urine and faeces is possible by usingurine-separating (or urine-diverting) toilets, available assimple dry toilets or porcelain flush toilets with dividedbowls. The risk for transmission of disease when handling andreusing the urine is largely dependent on thecross-contamination by faeces. In this research, the presenceof human faeces in urine samples was successfully determined byanalysing for faecal sterols. Cross-contamination was evidentin 22% of the samples from urine collection tanks, and in thesequantified to an average (± SD) of 9.1 ± 5.6 mgfaeces per litre urine. Testing for indicator bacteria wasshown to be an unsuitable method for determining faecalcontamination in human urine since<i>E. coli</i>had a rapid inactivation in the urine and faecalstreptococci were found to grow within the system.</p><p>The fate of any enteric pathogens present in urine iscrucial for the risk for transmission of infectious diseases.Gram-negative bacteria (e.g.<i>Salmonella</i>and<i>E. coli</i>) were rapidly inactivated (time for 90%reduction, T₉₀<5 days) in source-separated urine at itsnatural pH-value of 9. Gram-positive faecal streptococci weremore persistent with a T₉₀of approximately 30 days. Clostridia sporenumbers were not reduced at all during 80 days. Similarly,<i>rhesus</i>rotavirus and<i>Salmonella typhimurium</i>phage 28B were not inactivated inurine at low temperature (5°C), whereas at 20°C theirT₉₀-values were 35 and 71 days, respectively.<i>Cryptosporidium</i>oocysts were less persistent with a T₉₀of 29 days at 4°C. Factors that affect thepersistence of microorganisms in source-separated human urineinclude temperature, pH, dilution and presence of ammonia.</p><p>By using Quantitative Microbial Risk Assessment (QMRA), therisks for bacterial and protozoan infections related tohandling and reuse of urine were calculated to be<10^-3for all exposure routes independent of the urinestorage time and temperature evaluated. The risk for viralinfection was higher, calculated at 0.56 for accidentalingestion of 1 ml of unstored urine. If the urine was stored at20°C for 6 months the risk for viral infection was reducedto 5.4 × 10^-4.</p><p>By following recommendations for storage and reuse, whichare dependent on the type of crop to be fertilised, it ispossible to significantly decrease the risk for infections. Sofar, the level of risk that is acceptable is unknown. Theacceptable risk will be one of the main factors determining thefuture utilisation of source-separated human urine inagriculture.</p><p><b>Keywords:</b>urine-separation, urine, wastewater systems,wastewater reuse, recycling, enteric pathogens, faecal sterols,indicator bacteria, hygiene risks, microbial persistence,microbial risk assessment, QMRA, fertiliser, crop.</p>

The soils used by the East Coast Organic Producers Trust (ECOPT; the grower group that this study is targeted towards) have exceptionally low soil Olsen P concentrations (ca. 6 mg/L). These and other limitations (e.g. poor weed and pest and disease control) result in many ECOPT growers being unable to produce economic yields on anything other than small scale gardens. Fertilisers and manures are seldom used by these growers, which exacerbates the problem. Thus, the object of this research was to provide information to ECOPT on which fertilisers and application strategies would provide the best returns on their phosphorus (P) fertiliser investment. The experimental work was carried out in two parts. A laboratory study tested a range of phosphate rock (PR) based fertilisers and application rates; Ben Guerir reactive phosphate rock (RPR; 67, 133, 267, 533 and 1,333 mg P/kg soil), BioPhos and BioSuper (267 and 1,333 mg P/kg soil) and a no fertiliser Control. Soil fertiliser mixtures were incubated for 155 days and periodic measurements of PR dissolution, soil pH and Bic-P (analogous to Olsen P but expressed in µg/g) were undertaken. The field study used fewer application rates and two application methods; banded and broadcast. Broadcast plots were applied at 678 mg P/kg soil (488 kg P/ha); banded RPR was applied at 236, 678 and 1475 mg P/kg soil (40, 115 and 250 kg P/ha respectively) and banded BioPhos and BioSuper at 678 mg P/kg soil (115 kg P/ha). A Control was also included. Fertilisers were applied in October 2004 and changes in soil pH and Bic-P were measured in the broadcast plots only over a 344 day period. Potato (Solanum tuberosum L. cv. Desiree) was the test crop. Regression analysis was used to generate exponential equations to describe the changes in Bic-P over time (∆Bic-P). Differences between fertilisers in the amount of P dissolved and pH fluxes were used to explain the differences in ∆Bic-P. BioSuper dissolved quicker and generated greater ∆Bic-P than RPR and BioPhos, which were similar. Higher application rates produced greater increases in Bic-P than lower rates but decreased the % of P applied that dissolved. The increase in Bic-P over time from fertiliser application was much slower in the field compared with the laboratory. This was put down to differences in experimental conditions; mainly soil pH and soil aggregate surface area. Potato tuber yield (mean = 35 t/ha) did not respond to any of the fertiliser treatments despite a significant increase in P concentration of the shoots mid-way through the season in all broadcast treatments (shoot P concentration was not analysed in the banded plots). Water and N availability were the main limiting factors in this season as the crop was not irrigated and soil N supply was insufficient to produce a full canopy. Phosphorus response curves generated using the fertiliser response model PARJIB (Reid, 2002), and an economic analysis, indicated that for RPR and BioPhos the optimum economic application rate was 200 kg P/ha and for BioSuper it was 100 kg P/ha (applied every third and second year respectively).

Greater use of technology to assist aerial application of fertiliser will be of benefit to the topdressing industry and farmers. Benefits arise through automating the fertiliser flow control system; reducing off target fertiliser application, and managing fertiliser inputs based on the potential outputs of the farmland; thus increasing the profitability of hill country farming systems. A case for technology assisted application is developed by investigating the field performance of conventional and enhanced flow control systems and the effect of variable rate application on hill country pasture production. A single particle model that predicts flight trajectory from the particle force balance based on the aircraft groundspeed, axial and tangential propeller wash, wind characteristics and particle properties including sphericity was developed. Model predictions were compared to predictions from AGDISP 8.15. Results and trends were similar. The single particle ballistics model described above was extended to predict the lateral distribution of fertiliser after release from an aircraft. To achieve this, two parameters are important, the transverse flow profile of material leaving the hopper gatebox and the sphericity of the particles. Techniques for measuring these parameters are described and experimental results are presented for superphosphate. These data were used in the model to predict the lateral distribution pattern from a Gippsland Aeronautics 200C for a known discharge mass, which was compared to a measured pattern from the same aircraft for the same discharge mass. Good agreement between the shapes of the two distributions was found. The transverse distribution model provides a practical tool for optimising the design of spreaders, or optimum particle characteristics for a given spreader. It has the ability to predict the distribution profile of any particle size distribution from each, or all, of the spreader ducts. Culmination of the single particle and transverse distribution models led to the development of a deposition footprint model that was capable of predicting field application within a 25 ha trial site. The deposition footprint model was embedded inside a geographical information system and comparisons were made between the actual and predicted deposition across a series of transect lines. Good agreement was found. Following this, a comparison of the predicted field performance between an automated and manual control system were made. Economic benefits for a single application of superphosphate were identified through using automated control, where 10% less fertiliser was applied outside of the application zone when compared to the manually operated system. This equated to a net benefit of NZD $2800 for a 1500 ha hill country farming system. The value of improving the performance of a topdressing aircraft, on an industry level, was also examined. Cost/benefit analysis between a manual and automated system revealed a benefit of NZD $111,700 yr-1 for a single topdressing aircraft using the automated system. The economic impact of Variable Rate Application Technology (VRAT) is examined, using Limestone Downs as an example. The spatially explicit decision tree modelling technique was used to predict the annual pasture production over the entire Limestone Downs property. The resulting decision tree classes tended to follow the farm's digital elevation model. A series of six different fertiliser application scenarios were developed for comparison to a base line scenario using conventional aerial application techniques. VRAT outperformed the fixed rate applications in terms of pasture production and fertiliser utilisation. Full variable rate application and a model optimised prescription map, produced the highest annual pasture yield. Variable rate techniques were predicted to increase annual production and the spatial variability of that production. An economic analysis of the six production scenarios was undertaken. Farm cash surplus was calculated for each scenario and clearly revealed the benefits of using variable rate application technology. VRAT was found to be the most efficient and highest returning application method per hectare. Additional costs and increased charge-out rates were likely to occur under VRAT; nevertheless, the analysis indicated that significant financial incentives were available to the farmer. A sensitivity analysis revealed that even with a 20% increase in charge-out rate associated with VRAT, the farm's annual cash position varied by only $4500 (0.4%), suggesting the cost of implementing such a system is not prohibitive and would allow aircraft operators to add value to their services.

Sulphur is an important nutrient to plants, and reports of its deficiency have been increasing worldwide. Sulphur starvation causes losses in both yield and quality, and it reduces nitrogen use efficiency of plants. As the timing for fertilisation can be decisive for avoiding deleterious effects, improvements in the description of the sulphur balance in fields are a valuable contribution for assisting fertiliser management. Sulphate is the most important inorganic form of sulphur in soils. Being the mobile form, sulphate is readily available for plants, and also prone to be leached. Therefore the description of the movement of sulphate is the key component of the sulphur balance. Leaching of sulphate from the soil can be significantly delayed by its adsorption onto the soil particles. Soil type and pH are the main factors defining the sulphate adsorption capacity; although the presence of other ions in the soil solution can have a considerable effect. It has been reported that in some soils, typically volcanic and tropical soils with variable-charge characteristics, the co-presence of sulphate and calcium can substantially enhance their retention via ion-pair adsorption (IPA). To determine the influence of cations on the movement of sulphate, series of batch and miscible displacement experiments were conducted using two New Zealand soils, of contrasting ion adsorption capacities: the Taupo sandy and Egmont loam soils. These experiments demonstrated the occurrence of cooperative adsorption of sulphate and calcium in the Egmont soil, but not in the Taupo soil. Batch experiments were conducted to examine the IPA adsorption process in the Egmont soil in more detail. Based on the analyses of the results from these two series of experiments, plus the review of published data, three different mathematical approaches for evaluating the amount of solute adsorbed as ion-pairs are proposed. A computer program was built for solving an adsorption model using these three approaches, and was used to compare the model's predictions and the observed adsorption data. An extension of this program, coupling the adsorption model with a solute transport description, was used to simulate the movement of sulphate and calcium. Comparisons between the data from the miscible displacements and the results from this model are used to demonstrate the applicability of the proposed IPA description for modelling the transport of these ions in the soil. Finally, results from a pot trial with Egmont soil are used to examine the relevance of IPA for the movement of sulphate under non-equilibrium conditions, and with active plant growth. Although the results from this experiment regarding IPA were statistically non-significant, some insights could be obtained and are discussed. More studies involving IPA under non-equilibrium experiments are needed for a better understanding of the relevance of IPA in field conditions.

SANITATION, PUBLIC HEALTH AND THE ENVIRONMENT The approach to sanitation worldwide should be ecologically sustainable, i.e. concerned with protection of the environment. This means that sanitation systems should neither pollute ecosystems nor deplete scarce resources. It further implies that sanitation systems should not lead to degrading water or land and should, where possible, ameliorate existing problems caused by pollution. More research and better designs are needed. Human excreta can be rendered harmless, and toilet designs that do this in harmony with agricultural and social customs hold promise for the future. Problems with conventional sanitation systems have been shown to include inadequate institutional capacity to deal with the sanitation process, a fixation with providing either a full waterborne system or a VIP toilet, the social acceptability of various systems, and the perception that dry, on-site sanitation systems are inherently inferior. The basic purpose of any sanitation system is to contain human excreta (chiefly faeces) and prevent the spread of infectious diseases, while avoiding damage to the environment. An alternative sanitation technology known as urine-diversion (UD) performs these functions with fewer operational and maintenance problems than those associated with conventional VIP toilets, (for example, it is a major and expensive operation to desludge full pits, which is not the case with UD toilets as the vaults can be quickly and easily emptied using hand tools) and also provides a free, easily accessible and valuable agricultural resource for those who wish to use it. This technology represents one aspect of an approach, or philosophy, termed “ecological sanitation” or “ecosan.” Key features of ecosan are prevention of pollution and disease caused by human excreta, treatment of human excreta as a resource rather than as waste, and recovery and recycling of the nutrients. In nature, excreta from humans and animals play an essential role in building healthy soils and providing valuable nutrients for plants. Conventional approaches to sanitation misplace these nutrients, dispose of them and break this cycle. UD systems have been successfully implemented in many countries, including South Africa where more than 60 000 of these toilets have been built since 1997. However, despite much research having been carried out internationally and locally, various questions still remain, particularly on the health aspects of operation, maintenance, and excreta use or disposal. Not enough is known about the dehydrating processes taking place inside the faeces vault, and there is still disagreement on safe retention periods and microbiological stability of the final product. The roles of dryness, pH, temperature and time in pathogen destruction also need to be further clarified. In addition, it is critically important that toilet users are able to operate and maintain their systems easily and safely, particularly while emptying the vaults and recycling or otherwise dealing with the contents. Engineers need to understand and take all these issues into consideration before they can properly design and implement sustainable UD sanitation systems. It is therefore important to develop guidelines for sanitation practitioners that set out best practices for construction and operation of UD toilets. Construction recommendations are important because good construction facilitates easy operation, and also promotes rapid pathogen destruction. Easy operation in turn directly influences the health risks associated with removing faecal material from the vaults. Handling of faecal material is an aspect inherent in the operation of UD ecological sanitation systems, because emptying of the vault is usually done using hand tools. If the faecal material is also used for agricultural purposes then further handling must of necessity take place. As such, there is a health concern, both for the person(s) handling the material and for the wider public who may be consumers of the fertilised crops. It is therefore necessary that these health concerns be quantified, in order that proper regulation may take place. <b<CONCLUSIONS FROM THE LITERATURE REVIEW The primary aim of sanitation is to prevent the transmission of excreta-related diseases. However, with all sanitation systems there is a risk of disease transmission related to the handling or use of the end product. Therefore, even a well functioning system could enhance pathogen survival and lead to an increased risk of disease transmission for those handling the end products or consuming crops fertilised with them. A greater understanding of pathogen die-off in dry sanitation systems is required where handling and/or use of excreta are expected. Pathogen destruction in dry sanitation systems, particularly in the vaults of urine-diversion (UD) toilets, is mainly dependent on storage time, pH, temperature, humidity, moisture content, organic content of the faecal material, and type of bulking agent added. It is of utmost importance to ensure that the material is safe to handle. This implies that the primary treatment in the vault should, as far as possible, ensure the required level of safety. While much research has been carried out internationally into pathogen destruction in the vaults of UD toilets, the same cannot be said of South Africa. There is also a wide range of results and conclusions, with recommended storage times varying from six months to two years. Construction and operational guidelines are required in order to assist practitioners in these and other respects. Sound management practices could play an important role in reducing the health risks involved in emptying the vaults of UD toilets and the disposal or further use of faecal material. From the public health viewpoint, it is necessary to reduce, as far as possible, the risk of handling faecal material. To do this, a better understanding of the factors influencing pathogen die-off in the vaults is required. FOCUS OF THIS THESIS The primary aim of this thesis is to investigate the efficacy of various methods aimed at enhancing pathogen destruction in the vaults of UD toilets, with the aim of (a) establishing the best combination of factors/methods, in particular the vault storage period required, and (b) producing guidelines for the construction, operation and regulation of these systems. The overall purpose of the research is to establish safety criteria for handling of faecal material from UD toilets. FIELD TRIALS: MICROBIOLOGICAL EFFECTS ON FOOD CROPS FERTILISED WITH FAECAL MATERIAL FROM URINE-DIVERSION TOILETS Recycling excreta to soils reduces the need for chemical fertilisers; however, pathogens are recycled to humans if improper agricultural practices are followed. Concerns about using faecal material include higher pathogenic content in developing countries compared to that in developed countries. This material, as well as that from other sanitation alternatives in small-scale systems, demands more personal involvement from the users (including handling), which constitutes a higher human exposure level compared to that from conventional piped systems. Nevertheless, it is considered that where the material can improve agricultural productivity, it can contribute to improving the nutritional status of the population, thus improving public health. Although ecosan technology is spreading all over the world, and with it the recycling of excreta to soils, only a few researchers have addressed the problems associated with the revalorization practice or documented the pathogen die-off. Moreover, little data about the microbial quality of ecosan faecal material from developing countries (where the health risks are the highest) are available. The objective of this research was thus to investigate the potential health risks of using faecal material in agriculture by determining the pathogen uptake on the surfaces of the edible portions of the crops. Faecal material of between one and three months old was extracted from a number of UD toilets in the eThekwini (Durban) municipal area. This was used primarily for the experimental work described in the next section, but for the purposes of this particular experiment it was first left in a heap in the open air for a further four months. Thereafter it was used as a soil amendment in the cultivation of spinach and carrots. Detailed microbiological tests were conducted on this material as well as on the in situ soil before sowing and after harvesting, on the irrigation water, and on the harvested crops. Applying different rates of material to spinach and carrots, two common edible crops, it was found that the bacteria and fungi content were only noticeable for the higher application rates (>35t/ha), while the helminth ova content varied, both in leaves and stems, depending on the quantity of material applied. Helminth ova content was, for both crops, more prevalent in leaves, suggesting that the ova adhere preferentially to plants rather than soil. It was thus illustrated that there is a health implication involved in growing edible crops in soils amended with ecosan biosolids. Even if in this case the spinach and carrots were cooked before consumption, normal handling of the crops during harvesting and preparation could have caused infection if personal hygiene was unsatisfactory. It is therefore important that crop growers and consumers, as well as proponents of biosolids use, are aware of the storage and treatment requirements for ecosan biosolids before these are applied to soils where crops are grown. DETAILED INVESTIGATION INTO VAULT PROCESSES It is hypothesised that the most advantageous approach to pathogen destruction in a UD toilet vault is to maximise the effects of various environmental factors, e.g. high pH, high temperature, low moisture, type of bulking agent and storage time. In order to quantify these effects a field experiment was set up consisting of 12 UD toilet vaults, each with a different combination of faeces and bulking agent (soil, ash, wood shavings, NaOH or straw), ventilation (ventpipe / no ventpipe) and vault lid material (concrete, metal or perspex). Faecal material was obtained from UD toilets in the eThekwini area, as described above. Temperature probes, which were connected to a data logger, were inserted in the heaps and the logger monitored over a period of nearly 10 months. This enabled a number of graphs to be drawn illustrating the effect of the above parameters on heap temperature over the experimental period. During the coldest week in winter the mean heap temperatures averaged 16,8°C, while the minimum and maximum averaged 14,8°C and 18,8°C respectively. During the warmest week in summer mean heap temperatures averaged 27,6°C, while the minimum and maximum averaged 25,6°C and 29,3°C respectively. In addition, samples were taken at various intervals from each vault as well as from the main heap of faecal material that was left exposed to the elements. The samples were subjected to microbiological testing in order to quantify the pathogen die-off over time for each vault as well as for the main heap. In the vaults, total coliform reduced by 3 log10 (99,9%) at between 130 and 250 days, faecal coliform between 100 and 250 days, and faecal streptococci from 125 days and longer. In the main heap, these times varied from 115 days for both total and faecal coliform to 140 days for faecal streptococci. Viable Ascaris ova were reduced to zero between 44 and 174 days in the vaults and by 44 days in the main heap. The conclusions drawn from the xperimentation were the following: <ul> <li>Influence of ventpipe Ventilation of the vault by means of a ventpipe does not result in any meaningful difference in either the vault temperature or rate of pathogen die-off.</li> <li>Influence of vault lid material The lid material, and by inference also the material of the vault walls, has no significant effect on the temperature of the heap or the associated pathogen die-off.</li> <li>Type of bulking agent While the type of bulking agent used does not significantly influence the temperature of the faecal material, it does have an effect on the rate of pathogen die-off. The ordinary soil mix was seen to give the best results, and this was ascribed to the effect of competing microorganisms in the soil itself.</li> <li>Influence of sunshine and rain The main heap of material (faeces/soil mix) that was exposed to the elements performed among the best in terms of pathogen die-off. Apart from the influence of competing microorganisms in the soil on the pathogens as described above, this good performance was also ascribed to the effect of UV radiation and alternate wetting/drying and heating/cooling cycles, which suggests that open-air exposure is likely to provide the best treatment.</li></ul> Comparing the results of this research with other local and international research, it appears that there is a great deal of convergence in the results. It is concluded that vaults of UD toilets should be sized for a storage period of 12 months from last use. RECOMMENDATIONS FOR CONSTRUCTION, OPERATION AND REGULATION OF URINE-DIVERSION TOILETS The standard of UD toilets in South Africa varies greatly. While there are many good examples of the technology, there are also many that have been ill-conceived and are badly built and poorly operated. Project implementers are responsible for the quality of sanitation schemes and should be equipped with the necessary information to oversee the process. The guidelines are aimed at providing implementers with, firstly, the necessary technical information to build good quality UD toilets and, secondly, the basic operation and maintenance tasks that should be conveyed to the toilet owners. Basic regulatory guidelines for the responsible authorities are also given. The guidelines are intended to be a stand-alone document and some repetition of information from earlier chapters is thus unavoidable. The technology of urine diversion is introduced, followed by basic design and construction guidelines, including drawings, for the superstructure and vault of a UD toilet. Both single- and double-vault toilets are discussed. A number of photographs are also provided, illustrating good and bad building practices. Further aspects discussed are requirements for urine pipes and ventilation. Operation and maintenance of UD toilets are subsequently covered. Topics discussed are dehydration, odour, fly control, cleaning of the pedestal, disposal of anal cleansing material, urine collection and disposal, clearing of blockages in urine pipes, and faeces management. The above guidelines are aimed at designers, builders and toilet users. However, organisations responsible for administering public and environmental health, such as Departments of Health, Environmental Affairs, etc, as well as the local and regional authorities that actually implement the sanitation schemes, should become actively involved in regulating the operation of UD toilets, particularly the removal and disposal of faecal material. Some regulatory guidelines are therefore also included to assist these organisations to set uniform (high) standards in their respective jurisdictions. RECOMMENDATIONS FOR FURTHER RESEARCH RELATED TO THIS THESIS It is deemed important that the field trials conducted in the various vaults as described earlier are repeated in other climatic areas, for example a hot and dry area, as it is likely that different results regarding recommended minimum storage periods will be obtained. This should be supplemented by trials involving co-composting of the faeces mix with other organic material, in order to compare the efficacy of this method with the dehydration process. Further, vault lids made of PVC should be tested for enhancing heat gain in the vaults. Finally, long-tem measurements of heap pH should be made in order to ascertain if high pH amendments (wood ash, lime, etc) do in fact maintain their initial pH level. Additional field trials, similar to those described earlier for spinach and carrots, should be undertaken with a view to making recommendations regarding maximum application rates of faecal material. These should consist of food crops where the edible portions are either in or near to the soil, such as beetroot, onion, potatoes, tomatoes, etc. Trials involving urine should also be considered in order to determine the most advantageous application rate for the various crops. Another important topic is recommended for further research on the subject of UD toilets. At present, virtually all the UD toilets built in the country have been for communities on the lower end of the income scale and who previously had no formal sanitation facility at all or, at best, an unimproved pit toilet. Research carried out by CSIR in a number of communities has revealed people’s resistance to handling their faecal material, while in others it has not been a problem. There is often a general viewpoint in a village that “the municipality must take the faeces away.” However, willingness has also been expressed in some villages to pay for a faeces removal service. For instance, this has borne fruit in an area of Kimberley with UD toilets where householders pay a local resident to remove the faecal material on a regular basis. This is done by means of a wheelbarrow, and the material is stockpiled at a nearby approved facility from where it is destined for co-composting with other municipal waste. However, this has not yet been attempted on a large scale in an area with hundreds, or even thousands, of UD toilets. While a theoretical desktop study has been carried out on the feasibility of setting up a large-scale faeces collection concern, such an enterprise does not yet exist in the country. It is suggested that one be set up utilising a horse- or donkey-drawn cart in a village, or group of villages, with sufficient UD toilets available to ensure that a viable business can be conducted. The cooperation of the particular local authority will be required. If successful faeces collection/disposal services could be established in areas with UD toilets it would greatly enhance the social acceptability, and therefore the viability, of this sanitation technology. / Thesis (PhD(Civil Engineering))--University of Pretoria, 2008. / Civil Engineering / unrestricted

As Kungsängens wastewater treatment plant is considering a move, it opens up a possibility to implement nitrogen recovery technologies that comply with current and future legislative requirements. Nitrogen recovery offers simultaneous treatment of wastewater and collection of concentrated ammonia products for fertiliser production. This can create a circular and sustainable solution by reduced energy consumption, greenhouse gas emissions and nitrogen pollution. Despite the large amount of research that has been performed on this topic, practical use at wastewater treatment facilities in Sweden are still scarce. The aim of the degree project was to identify nitrogen recovery technologies and investigate their potential impact at a new Kungsängens wastewater treatment plant. A literature review provided different nitrogen technologies and concept scoring was used to rank and score them. Gas permeable membrane and ammonia stripping ranked the highest and both have the potential to be implemented at Kungsängens current or possible new site. Simulations were used to identify the change in energy consumption and change in effluent water quality related to the implementation of a nitrogen recovery technology. Calculations were performed to reach thequantities of nitrogen that could be recovered, and it was found that the nitrogen recovery potential was 0,2343 ton/d using gas permeable membrane, and 0,2750 ton/d using ammonia stripping. By replacing artificial fertilisers with recovered nitrogen, 7,95 kWh/kg N could be saved using gas permeable membrane and 2,76 kWh/kg N could be saved using ammonia stripping. The degree project also provides insight into European and Swedish lawconformity and predictability. Finally, a discussion of environmental impacts, potential for nitrogen recovery, nitrogen policies, and energy savings was conducted. It was concluded that nitrogen recovery can create benefits due to avoided nitrous oxide emissions, avoided production of precipitation chemicals and decreased energy consumption for aeration. Compared to artificial fertiliser produced using the Haber-Bosch method, it was determined that a significant reduction of carbon dioxide emissions could be reached.