James Frederickson

Combining vermiculture with traditional green waste composting systems

Freshly-shredded green waste (yard waste) was composted for 16 weeks using a mechanically-turned windrow system. The rate of organic matter stabilisation was determined by measuring the reduction in the volatile solids content of the waste. Samples of the fresh material were also vermicomposted using Eisenia andrei (Bouche) and rates of growth and reproduction obtained which were comparable to published rates for other wastes. Vermicomposting for 8 weeks produced a material with a significantly lower volatile solids content compared to composting for a similar period (P < 0.01). A combined composting and vermicomposting system was investigated by extracting partially-composted samples from the compost windrow every 2 weeks and feeding these to E. andrei. Growth and reproduction were found to be positively correlated to the volatile solids content of the waste (P < 0.01). Vermicomposting partially composted waste (2 weeks), for a further 6 weeks, reduced volatile solids content significantly more than for composting fresh waste for 8 weeks (P < 0.001). It is concluded that E. andrei is capable of attaining good rates of growth and reproduction in fresh green waste and that vermicomposting can result in a more stable material (lower volatile solids content) compared to composting. Combining vermicomposting with existing composting operations can also accelerate stabilisation compared to composting alone. The duration of pre-composting will determine the subsequent rate of growth and reproduction of E. andrei. To ensure that the vermicomposting system operates at maximum efficiency, pre-composting should be kept to a minimum, consistent with effective sanitisation of the waste.

Composting municipal waste in the UK: some lessons from Europe

Composting is an important element in sustainable waste management for the UK and could potentially have a vital role to play in meeting the obligations of the Landfill Directive. This paper evaluates the current state of the composting industry in the UK using the survey data from 1999 and compares its performance and profile with other countries in Europe. The UK industry profile shows that most waste (92%) is managed by relatively small, centralised sites which typically employ unsophisticated technology. These centralised sites also tend to compost green (garden) waste almost exclusively and this material is usually obtained from collection at civic amenity sites. In relation to the longer-term requirements of the Landfill Directive, it would appear that continued reliance on composting green waste would not be sufficient to meet the targets. Major structural changes will be needed if the industry is to meet the challenges ahead and kerbside collection and composting of both kitchen and green waste will probably have an important role to play. The results from the 1999 survey of composting also suggest that there is a renewed interest in using mechanical and biological treatment to process municipal solid waste directly. After several years of sustained growth, it is clear that the UK composting industry is at a crucial stage in its development. It is the opinion of the authors that the experience of the more advanced composting countries in Europe should be used as a model for the continued development of the UK industry in order to deliver sustainable waste management in the longer term.

The intensive production of lumbricus terrestris L. for soil amelioration

Abstract The benefits of earthworm inoculation in improving soil conditions are now well established. The main problem with this technique is that it is difficult to obtain large numbers of the most appropriate species at an economic price. At present, the only way of obtaining earthworms for soil improvement is from large scale field collection and this is laborious and expensive. Research at the Open University aims to overcome these problems by investigating ways of intensively producing Lumbricus terrestris . This paper identifies the key variables in the process and presents experimental evidence that L. terrestris can grow and reproduce all year round. Initial results indicate that by optimising the key variables of temperature and nutrition this species can be grown from cocoon to sexual maturity in less than half the time taken in the field. Furthermore, the rate of reproduction can be increased to twice the maximum rate reported by other researchers, even when the earthworms are kept at densities much higher than found in the field. It is concluded that continuous, intensive production of L. terrestris is possible and that this method of supplying earthworms for soil improvement has many advantages compared to field collection.

An earthworm cultivation and soil inoculation technique for land restoration

Abstract The introduction of selected earthworms into degraded or newly restored land is known to promote soil improvement. However, to collect and introduce the large numbers required for use in land restoration can be costly and time consuming. To overcome these problems, an Earthworm Inoculation Unit (EIU) technique combines cultivation of selected earthworms in soil-based units with an effective method of direct soil introduction. Cultivation of a particular deep-burrowing species was achieved through optimizing temperature, nutrition and population density. At soil inoculation, after 3 months, each 2-l EIU contained all three life stages - adults, cocoons and hatchlings - providing maximum opportunity for successful colonization. Compared with a conventional method of inoculation, the EIU technique gave rise to enhanced survivorship in a compacted clay soil during the first year after inoculation. Earthworm inoculation should become an integral component of sustainable land restoration practice and the EIU technique provides the most effective means of ensuring long-term earthworm colonization, particularly in hostile soil environments.

The Earthworm Inoculation Unit technique: An integrated system for cultivation and soil-inoculation of earthworms

Abstract The introduction of earthworms into degraded or newly restored land is known to promote soil improvement. Obtaining the most appropriate species in the large numbers required can be costly and time consuming using traditional techniques. Research and development of a novel approach, the Earthworm Inoculation Unit (EIU) technique, may help to overcome this. This technique combines cultivation of selected earthworms in small soil-based units, with an effective method of direct soil introduction. Successful cultivation of deep burrowing species, e.g. Lumbricus terrestris L. and Aporrectodea longa (Ude), and shallow working species, e.g. Allolobophora chlorotica (Savigny), has been achieved by optimizing environmental factors. Accelerated rates of reproduction compared with field data have been recorded. At soil-inoculation, each EIU was found to contain all three earthworm life stages, adults, cocoons and hatchlings, promoting maximum opportunity for successful colonisation. Reselts from field trials suggest, that for A. longa , the EIU technique can enhance survivorship in compacted clay soils compared with a more conventional inoculation method. Earthworm inoculation, where appropriate, should become an integral component of sustainable land restoration practice. In hostile soils, often associated with reclaimed land, the EIU technique may provide a means of ensuring long term survival for earthworm populations.

Large-scale vermicomposting: emission of nitrous oxide and effects of temperature on earthworm populations: The 7th international symposium on earthworm ecology · Cardiff · Wales · 2002

A large-scale, outdoor vermicomposting system was monitored for 80 weeks. Earthworm populations were recorded for 60 weeks in unheated beds operating at ambient temperatures (34 weeks at 6.3 ′ 2.3 °C) and in heated beds controlled at 13.7 ′ 0.8°C for 34 weeks. Both blocks of beds were at ambient temperatures for the remaining 26 weeks. Earthworm biomass and the numbers of hatchlings and cocoons produced for the heated beds were found to be significantly greater than for the unheated beds. Nitrous oxide fluxes in winter (week 60) were 3.2 ′ 0.3 mg m - 2 h - 1 (unheated beds), 1.8 ′ 0.3 mg m - 2 h - 1 (heated beds), and these were significantly different to the control beds (0.1 ′ 0.0 mg m - 2 h - 1 ). Emissions during summer (week 80) were 20.1 ′ 3.0 mg m - 2 h - 1 (unheated beds), 21.3 ′ 2.8 mg m - 2 h - 1 (heated beds) and these were significantly different to the control beds 3.9 ′ 1.7 mg m - 2 h - 1 . No relationship between earthworm density and nitrous oxide flux was found for the large-scale beds. However, in a subsequent laboratory experiment, nitrous oxide emissions were positively correlated with earthworm density (R 2 = 0.76). Maintaining moderate bed temperatures for vermicomposting systems during low ambient temperatures can significantly increase earthworm density. Vermicomposting systems have the capacity to emit high levels of nitrous oxide and earthworms appear to be primarily responsible for this. The environmental impact from nitrous oxide emissions appears to be comparable to other waste processing operations. Further research is required into ways of minimising emissions especially from vermicomposting systems operating at high earthworm densities and high waste processing rates.

Static, dynamic and inoculum augmented respiration based test assessment for determining in-vessel compost stability

The purpose of this work was to evaluate compost (and related industry) stability tests given recent large-scale changes to feedstock, processing techniques and compost market requirements. Five stability tests (ORG0020, DR4, Dewar self-heating, oxygen update rate (OUR) and static respiration) were evaluated on composts from ten in-vessel composting sites. Spearman rank correlation coefficients were strong for the ORG0020, OUR and DR4 (both CO2 and O2 measurement), however, OUR results required data extrapolation for highly active compost samples. By comparison the Dewar self-heating and static respiration tests had weaker correlations, in part the result of under reporting highly active, low pH samples. The findings suggest that despite differences in pre-incubation period both dynamic respiration tests (ORG0020 and DR4) are best suited to deal with the wide range of compost stabilities found.

The Integration of Systemic and Scientific Thinking in the Development of an Innovative Process for Environmental Management

The growing debate on issues such as maintaining biological diversity and escalating environmental degradation have highlighted the need for systemic approaches to environmental management. For example, Ulrich (1993) proposes the concept of critical holism as being useful in the debate about designs or applications in the field of ecological thinking. Here, critical systems heuristics has been used to develop a number of boundary judgements which can be used to address the value, power and knowledge bases of particular designs, as well as their basis of legitimisation. Grumbine (1994) has argued that the concept of ecosystem management is an approach which offers a fundamental reframing of how humans work with nature because it ‘integrates scientific knowledge of ecological relationships within a complex sociopolitical and values framework toward the general goal of protecting native ecosystem integrity over the long term’. A number of themes underlie the concept such as the need for environmental managers to seek connections between all levels of the biodiversity hierarchy, to work across ecological and administrative boundaries and to conserve viable populations which also includes the reintroduction of species. Importantly he identifies adaptive management, where management is considered to be a learning process, as a theme and highlights the dominant role that human values play in ecosystem management goals.