An investigation of soil quality parameters relating to agricultural reuse and land disposal options for the management of biosolids

Sludge provides valuable nutrients to soil. Application of sludge to land is subject to a number of limitations. Its use as a soil conditioner represents a "beneficial reuse option". Primary and secondary sludge from Dublin city is treated in Ringsend treatment plant where it undergoes thermal drying. This study investigates the feasibility of land application of thermally dried biosolids (TDB) from Ringsend treatment plant.

An evaluation of septic tank effluent movement in soil and groundwater systems

Recent studies have shown that septic tank systems are a major source of groundwater pollution. Many public health workers feel that the most cri^cal aspect of the use of septic tanks as a means of sewage disposal is the contamination of private water wells with attendant human health hazards. In this study the movement and attenuation of septic tank effluents in a range of soil/overburden types and hydrogeological situations was investigated. The suitability of a number of chemical and biological tracer materials to monitor the movement of septic tank effluent constituents to groundwater sources was also examined. The investigation was divided into three separate but inteiTelated sections. In the first section of the study the movement of septic tank effluent from two soil treatment systems was investigated by direct measurements of soil nutrient concentrations and enteric bacterial numbers in the soil beneath and downgradient of the test systems. Two sites with different soil types and hydrogeological characteristics were used. The results indicated that the attenuation of the effluent in both of the treatment systems was incomplete. Migration of nitrate, ammonium, phosphate and fecal bacteria to a depth of 50 cm beneath the inverts of the distribution tiles was demonstrated on all sampling occasions. The lateral migration of the pollutants was less pronounced, although on occasions high nutrients levels and fecal bacterial numbers were detected at a lateral distance of 4.0 m downgradient of the test systems. There was evidence that the degree and extent of effluent migration was increased after periods of heavy or prolonged rainfall when the attenuating properties of the treatment systems were reduced as a result of saturation of the soil. The second part of the study examined the contamination of groundwaters downgradient of septic tank soil treatment systems. Three test sites were used in the investigation. The sites were chosen because of differences in the thicknesses and nature of the unsaturated zone available for effluent attenuation at each of the locations. A series of groundwater monitoring boreholes were installed downgradient of the test systems at each of the sites and these were sampled regularly to assess the efficiency of the overburden material in reducing the polluting potential of the wastewater. Effluent attenuation in the septic tank treatment systems was shown to be incomplete, resulting in chemical and microbiological contamination of the groundwaters downgradient of the systems. The nature and severity of groundwater contamination was dependent on the composition and thickness of the unsaturated zone and the extent of weathering in the underlying saturated bedrock. The movement of septic tank effluent through soil/overburdens to groundwater sources was investigated by adding a range of chemical and biological tracer materials to the three septic tank systems used in section two of the study. The results demonstrated that a single tracer type cannot be used to accurately monitor the movement of all effluent constituents through soils to groundwater. The combined use of lithium bromide and endospores of Bacillus globigii was found to give an accurate indication of the movement of both the chemical and biological effluent constituents.

The appraisal of mesophilic anaerobic digestion and thermophilic aerobic digestion in the treatment of municipal sludge in Ireland

It has been well documented that the optimum feedstock for anaerobic digesters consists of readily biodegradable compounds, as found in primary sludge or even a mixed substrate of primary and excess activated sludge. Due to the requirements of the Urban Wastewater Treatment Plant Directive of 1991, the quantities of secondary sludge generated is set to increase substantially. A pilot scale study was undertaken to evaluate the performance of both Mesophilic Anaerobic Digestion and Thermophilic Aerobic digestion in the treatment of secondary sludge. The results indicated that the anaerobic pilot scale digester achieved a greater solids destruction than the aerobic pilot plant averaging at 28% T.S. removal verses 20% for the aerobic digester, despite the fact that secondary sludge is the optimum feedstock for aerobic digestion. This can, however, be attributed to the greater biomass yield experienced with aerobic systems, and to the absence of Autothermal conditions. At present, the traditional technique of Mesophilic Anaerobic Digestion is in widespread application throughout Ireland, for the stabilisation of sewage sludge. There is only one Autothermal Thermophilic Aerobic Digester at present situated in Killarney, Co. Kerry. A further objectives of the study was to compare full-scale applications of Mesophilic Anaerobic Digestion to ATAD. Two Sludge Treatment plants, situated in Co. Kerry, were used for this purpose, and were assessed mainly under the following headings; process stability, solids reduction on average, the ATAD plant in Killarney has the advantage of producing a “Class A” Biosolid in terms of pathogen reduction, and can effectively treat double the quantity of sludge. In addition, economically the ATAD plant is cheaper to run, costing €190 / t.d.s verses €211 / t.d.s. for the anaerobic digester in Tralee. An overview of additional operational Anaerobic Digestion Plants throughout Ireland is also presented.

The appraisal of anaerobic digestion in Ireland to develop improved designs and operational practice

Mesophilic Anaerobic Digestion treating sewage sludge was investigated at five full-scale sewage treatment plants in Ireland. The anaerobic digestion plants are compared and evaluated in terms of design, equipment, operation, monitoring and management. All digesters are cylindrical, gas mixed and heated Continuously Stirred Tank Reactors (CSTR), varying in size from 130m3 to 800m3. Heat exchanger systems heat all digesters. Three plants reported difficulties with the heating systems ranging from blockages to insufficient insulation and design. Exchangers were modified and replaced within one year of operation at two plants. All but one plant had Combined Heat and Power (CHP) systems installed. Parameter monitoring is a problem at all plants mainly due to a lack of staff and knowledge. The plant operators consider pH and temperature the most important parameters to be measured in terms of successful monitoring of an anaerobic digester. The short time taken and the ease at which pH and temperature can be measured may favour these parameters. Three laboratory scale pilot anaerobic digesters were operated using a variety of feeds over at 144-day period. Two of the pilots were unmixed and the third was mechanically mixed. As expected the unmixed reactors removed more COD by retention of solids in the digesters but also produced greater quantities of biogas than the mixed digester, especially when low solids feed such as whey was used. The mixed digester broke down more solids due to the superior contact between the substrate and the biomass. All three reactors showed good performance results for whey and sewage solids. Scum formation occurred giving operational problems for mixed and unmixed reactors when cattle slurry was used as the main feed source. The pilot test was also used to investigate which parameters were the best indicators of process instability. These trials clearly indicated that total Volatile Fatty Acid (VFA) concentrations was the best parameter to show signs of early process imbalance, while methane composition in the biogas was good to indicate possible nutrient deficiencies in the feed and oxygen shocks. pH was found to be a good process parameter only if the wastewater being treated produced low bicarbonate alkalinities during treatment.

The effects of detergent loading on rotating biological contactor (RBC) wastewater treatment efficiency

There are presently over 182 RBC plants, treating domestic wastewater, in the Republic of Ireland, 136 of which have been installed since 1986. The use of this treatment plant technology, although not new, is becoming increasingly popular. The aim of this research was to assess the effects that a household detergent has on rotating biological contractor treatment plant efficiency. Household detergents contribute phosphorus to the surrounding environment and can also remove beneficial biomass from the disc media. A simple modification was made to a conventional flat disc unit to increase the oxygen transfer of the process. The treatment efficiency of the modified RBC (with aeration cups attached) was assessed against a parallel conventional system, with and without degergent loading. The parameters monitored were chemical oxygen demand (COD), bio-chemical oxygen demand (BOD), nitrates, phosphates, dissolved oxygen, the motors power consumption, pH, and temperature. Some microscopic analysis of the biofilm was also to be carried out. The treatment efficiency of both units was compared, based on COD/BOD removal. The degree of nitrification achievable by both units was also assessed with any fluctuations in pH noted. Monitoring of the phosphorus removal capabilities of both units was undertaken. Relationships between detergent concentrations and COD removal efficiencies were also analysed.

Development of an inspection regime for on-site domestic wastewater treatment systems

The overall purpose of this study was to develop a thorough inspection regime for onsite wastewater treatment systems, which is practical and could be implemented on all site conditions across the country. With approximately 450,000 onsite wastewater treatment systems in Ireland a risk based methodology is required for site selection. This type of approach will identify the areas with the highest potential risk to human health and the environment and these sites should be inspected first. In order to gain the required knowledge to develop an inspection regime in-depth and extensive research was earned out. The following areas of pertinent interest were examined and reviewed, history of domestic wastewater treatment, relevant wastewater legislation and guidance documents and potential detrimental impacts. Analysis of a questionnaire from a prior study, which assessed the resources available and the types of inspections currently undertaken by Local authorities was carried out. In addition to the analysis of the questionnaire results, interviews were carried out with several experts involved in the area of domestic wastewater treatment. The interview focussed on twelve key questions which were directed towards the expert’s opinions on the vital aspects of developing an inspection regime. The background research, combined with the questionnaire analysis and information from the interviews provided a solid foundation for the development of an inspection regime. Chapter 8 outlines the inspection regime which has been developed for this study. The inspection regime includes a desktop study, consultation with the homeowners, visual site inspection, non-invasive site tests, and inspection of the treatment systems. The general opinion from the interviews carried out, was that a standardised approach for the inspections was necessary. For this reason an inspection form was produced which provides a standard systematic approach for inspectors to follow. This form is displayed in Appendix 3. The development of a risk based methodology for site selection was discussed and a procedure similar in approach to the Geological Survey of Irelands Groundwater Protection Schemes was proposed. The EPA is currently developing a risk based methodology, but it is not available to the general public yet. However, the EPA provided a copy of a paper outlining the key aspects of their methodology. The methodology will use risk maps which take account of the following parameters: housing density, areas with inadequate soil conditions, risk of water pollution through surface and subsurface pathways. Sites identified with having the highest potential risk to human health and the environment shall be inspected first. Based on the research carried out a number of recommendations were made which are outlined in Chapter 10. The principle conclusion was that, if these systems fail to operate satisfactorily, home owners need to understand that these systems dispose of the effluent to the 'ground' and the effluent becomes part of the hydrological cycle; therefore, they are a potential hazard to the environment and human health. It is the owners, their families and their neighbours who will be at most immediate risk.

Untersuchung der Bedingungen und Verhältnisse beim Dickstoffversatz unter Einbeziehung der Mischtechnik

Technology of high concistency materials, mixing prozess, sewage sludge incineration ash, products of the flue gas cleaning, flow behaviour, reaction calorimetry, hydraulic transportation, setting

Freshwater sponges (Porifera, Demospongiae) indicators of some coastal habitats in South America: redescriptions and key to identification

Surveys for freshwater sponges were performed at several water bodies at sandy environments along a north-south direction of particularly the Brazilian coastal line. The results allowed for the distinction of four different species-specific environments along this coastal border. The main fact considered was the dominant or the sole recurrent occurrence of a single sponge species at one particular habitat. The first one is that of the lagoonal mesohaline habitats at the tropical and subtropical realms, indicated by Spongilla alba Carter, 1849. The second one refers to shallow ponds among dunes at the tropical area indicated by Corvoheteromeyenia heterosclera (Ezcurra de Drago, 1974). The third one is that of also shallow ponds close to the dune belt at the temperate region indicated by Racekiela sheilae (Volkmer-Ribeiro, De Rosa-Barbosa & Tavares, 1988). The fourth one is that of organically enriched environments, at the marginal areas of lagoons and mouth of small rivers, evolving towards freshwater muddy ponds and coastal swamps, not far from the ocean border: Ephydatia facunda Weltner, 1895 is the species to occupy this habitat with almost exclusiveness. The above species are thus proposed as indicators of such habitats and have their descriptions improved and that of their environments summarized. A taxonomic key based on the spicules of the four species is proposed. The results presented aim to contribute to the identification of spicules of these sponges in sediment columns recovered at the Brazilian and South American coastal area. Determination of paleo ocean borders are a present issue of upmost importance in what respects projections of timing and fluctuations of ascending/regressing sea levels.

Two new species of Caulleriella (Polychaeta, Cirratulidae) from Argentina

Caulleriella bremecae and C. galeanoi (Polychaeta: Cirratulidae) are newly described from Mar del Plata, Argentina (38ºS, 57ºW). Both species have small, red-pigmented nuchal organs (lateral "eyes") on the prostomium. Caulleriella bremecae sp. nov. is further characterized by a peristomium without annulations except for a narrow anterior dorsal fold, posterior part of peristomium extending posterodorsally over chaetiger 1, latter extending posterodorsally over chaetiger 2 and with slightly separated grooved palps arising middorsally; notochaetae of chaetigers 1-23 all smooth capillaries, thereafter with six bidentate sigmoid hooks and 3-4 capillaries, both types fewer on last 4-5 chaetigers; neurochaetae of chaetigers 1-2 comprised of 8 bidentate hooks and 1-2 capillaries, thereafter only bidentate hooks, decreasing in number posteriorly. The species is frequent and abundant throughout the year in the intertidal mussel beds situated 200-700m from the sewage outfall of Mar del Plata city. Caulleriella galeanoi sp. nov. is characterized by a peristomium with three annulations dorsally, with grooved palps arising from annulus 3, and by smooth capillary chaetae in noto- and neuropodia of chaetigers 1-2. Bidentate hooks are present in neuropodia from chaetiger 3, numbering 5-6 in anterior and middle chaetigers, 1-3 in posterior ones. Notopodia have 3-6 pairs of smooth capillary chaetae, decreasing in number posteriorly. From chaetiger 13-20, notopodia with 1-2 capillary chaetae and 1-2 bidentate hooks. Specimens held in aquaria supplied with water and the green alga Vaucheria sp. (Vaucheriaceae) from the intertidal zone reproduced asexually by fission. Gametes were not observed in any specimens.

Microsatellite genotyping from faeces of Lontra longicaudis from southern Brazil

A genetic study of the neotropical river otter Lontra longicaudis (Olfers, 1818), which has an unknown conservation status, was carried out at the Taim Ecological Station and the margins of the Vargas stream, Rio Grande do Sul, southern Brazil. Faecal samples were collected, and DNA was extracted using a silica-guanidine method. Five microsatellite loci were amplified using PCR with heterologous primers previously described for Lutra lutra (Linnaeus, 1758). Sixteen faecal samples out of 29 from Taim and 11 out of 14 from Vargas stream margins contained enough DNA for genetic analysis. A total of 49 different alleles were found at both localities, from which 18 were exclusively found in individuals from Taim and 17 were exclusives from Vargas individuals. The most common allele was the same at both locations for three loci (Lut715, Lut733, and Lut818). A high level of genetic diversity was found at both sites (NeTaim=4.1, HoTaim=0.299, HeTaim=0.681; NeVargas=4.9, HoVargas=0.355, HeVargas=0.724), being higher at the Vargas stream site. A high and significant level of heterozygote deficiency was observed at most loci according to the χ2 test. The homogeneity χ2 test (P<0.001) showed that there were significant differences in the allele frequencies between the two locations. Genotyping for more than one locus was possible in 81.5% of samples, from which only 37% were possible to genotype for more than three loci. A low degree of relatedness was found among individuals from Taim (R=0.055±0.310), but an even lower value of relatedness was found at the Vargas site (R= -0.285±0.440). The significant degree of differentiation (I=0.890; F ST=0.059) found between Taim and Vargas individuals suggests that there is more than one population of otters in the southern extreme of Brazil, which probably are associated with the water body systems found in this region, the Mirim and the Caiuvá/Flores/Mangueira Lagoons. The high genetic diversity and low relatedness found at the Vargas stream, lead us to believe that the Vargas stream may be acting as a corridor between these water bodies for otter dispersion.

Community structure of metazoan parasites of silverside, Odontesthes bonariensis (Pisces, Atherinopsidae) from Argentina

The helminth communities of silverside, Odontesthes bonariensis (Valenciennes, 1835), from two Argentinean lagoons were studied and compared at component community and infracommunity levels. Nine helminth species were found: five digeneans (Austrodiplostomum cf. mordax, Ascocotyle (Phagicola) cf. diminuta, Ascocotyle sp., Thometrema bonariensis and Saccocoelioides sp.); two nematodes (Contracaecum sp. and Hysterothylacium sp.); one acanthocephalan (Wolffhugelia matercula) and one cestode (Cangatiella macdonaghi). Odontesthes bonariensis is a new host record for five parasite species. Richness, diversity and number of helminths in silversides from Salada Grande lagoon were higher than in those from Lacombe lagoon. This could be related with lagoon size, abundance of mollusks and fish-eating birds, and size and diet of silversides captured in each lagoon. In Salada Grande lagoon the helminth community of silversides was dominated by the allogenic and generalist species A. cf. mordax; while the autogenic and intermediate specialist species C. macdonaghi was dominant in Lacombe lagoon. Host sex did not affect richness, diversity or total abundance, whereas host size was positively correlated with these attributes, except diversity in Salada Grande lagoon.

First records of Freshwater Bivalves of Ilha Grande National Park, Paraná, Brazil

The Ilha Grande National Park, Paraná, Brazil, is located in the Upper Paraná River and has characteristics typical of a floodplains. This protected area includes lagoons connected and disconnected to the Paraná River, although the latter also connect during periods of high water level, thus composing a heterogeneous group of lacustrine environments. The enormous potential the flora and fauna diversities are still little known to the region, as can be seen through benthic invertebrates, inclunding bivalves mollusks. The granulometric composition of these floodplain lagoons was formed mainly by mud and very fine sand. Furthermore, organic matter composition was predominantly of fine particulate. The other abiotic factors differed from lagoons located within the island of the park to those located in the left margin of Paraná River. The results demonstrated the importance of abiotic factors such as the physical composition of granulometric texture, organic matter and macrophyte banks, to the establishment of bivalves in these floodplain lagoons. We recorded bivalves of Pisidium (native), Diplodon (native), and Corbicula (invasive). The highest values of Diplodon sp. density were observed at São João/C lake, for Pisidium sterkianum (Pilsbry, 1897) at São João/M lake, and to Jatobá/C lagoon with high density of invasive species Corbicula fluminea (Müller, 1774). This study to obtain conduct the first records of freshwater bivalves in floodplains lagoon in the Ilha Grande National Park, and provides contributions to better understanding the ecology of these mollusks. The recording of native species in the region of Upper Paraná River floodplain after a lomg period without new records, demonstrated the importance of protecting the lagoons of the Ilha Grande National Park as they can be a possible refuge to some species of native freshwater bivalves.

Anfíbios Anuros do Distrito Federal

The frogs of the Federal District of Brazil are listed and discussed as to habit, biology and ecology. The F. D is situated 22° 54' 24" S. & 43° 10' 21" W Gr. and comprises 1.356 km². Its topography includes sea-shore, maritime scrub, lagoons, plains and marsh, open slopes, forested mountains and great heads of rock. Three thousand feet of altitude are attained at two points. Fifty two different frogs occur in the F.D. Three fifths of them live in open country. Two fifths of these have never been found above the plains; the others range higher but mostly in open country. Their environment offers conditions suitable for average tadpoles and adults. these frogs are more or less unspecialized. There are six genera and thirty species. Two thirds of the latter belong to the type genera of the large neotropical families Bufonidae, Leptodactylidae and Hylidae. Only in the maritime scrub formation are conditions somewhat different. Water for average tadpoles is provided by the lagoons. The xerophytism of the vegetation is, however, so marked that bromeliads growing on the ground provide almost the only appropriate shelter for adult tree-frogs used to sleeping upright on the vegetation. One large Hylid genus lives entirely in them. It is casque-headed and phragmotic, shutting the lumen of the leaf-cup with head used as a plug. Another large Hylid genus shows a lesser degree of the same specialization. (Lutz A & Lutz B, 1939 II). One genus with two species is entirely saxicolous; it lives on wet ledges of rock at all phases of its life history. (B. Lutz 1948). The other two fifths of the frogs from F. D. are montane forest forms. Their environment offers numerous and varied biotopes and is near optimum for adults. There is,however, hardly any standing water available for larvae. These frogs are ecologically diversified. They also show a general trend towards spawning in the adult biotipe, which leads to delayed hatching, semi-aquatic and terrestrial larvae and direct development. (B Lutz, 1948). The author interprets the morphological specialization of the casque-headed Hylids and the biological specialization of the montane forest forms as adaptive. Casque-headedness and phragmosis increase protection against blood-suckers and predators. The humidity of the rain forest permits eggs, embryos and larvae to develop, unharmed, outside their usual, aquatic, environment.