title: Adsorption of Colour from Pulp and Paper Mill Wastewaters onto Diatomaceous Earths

authors: Carter, Shane Basil

subjects: Adsorption of colour

abstract: Abstract

Production of pulp and paper from raw wood involves the washing of substantial quantities of highly coloured material from the wood pulp. Although most of this colour is trapped within the mill and the mills wastewater treatment system, discharge of coloured wastewater remains a problem of public concern.

Lake Rotorua, New Zealand is filled with sediment consisting almost exclusively of diatoms. The most abundant species, Aulacoseira, has been shown to have very small pores, less than 200 nm, that could be very useful for the capture and holding of large organic molecules. Lake Rotorua is situated close to the two largest pulp and paper mills in New Zealand and may have to be dredged to solve a problem of eutrophication. Wastewaters generated at the Kinleith (Tokoroa) and Tasman (Kawerau) mills in the North island of New Zealand have been used to assess the characteristics of colour removal by Lake Rotorua diatoms.

Vacuum filtration through the diatoms succeeded in removing colour but proved to be impractically slow as an industrial process. Addition of diatoms to wastewater streams in stirred experiments showed that significant adsorption took place. The majority of the colour was removed within 30 seconds of mixing. The efficiency of colour removal was found to vary between wastewater streams within the mills. The pH dependency of this removal was tested and found to be most effective in a pH range of 3.6 to 5.

Attempts to reuse the diatoms showed that chemical backwash regimes were more effective than calcination.

This study concluded that surface silanols were likely to be the principle agent in forming coagulants with the colour material and were subsequently trapped on the diatom surfaces, but more importantly within the pores.

text: Adsorption of Colour from Pulp and Paper Mill Wastewaters onto Diatomaceous Earths Abstract

Production of pulp and paper from raw wood involves the washing of substantial quantities of highly coloured material from the wood pulp. Although most of this colour is trapped within the mill and the mills wastewater treatment system, discharge of coloured wastewater remains a problem of public concern.

Lake Rotorua, New Zealand is filled with sediment consisting almost exclusively of diatoms. The most abundant species, Aulacoseira, has been shown to have very small pores, less than 200 nm, that could be very useful for the capture and holding of large organic molecules. Lake Rotorua is situated close to the two largest pulp and paper mills in New Zealand and may have to be dredged to solve a problem of eutrophication. Wastewaters generated at the Kinleith (Tokoroa) and Tasman (Kawerau) mills in the North island of New Zealand have been used to assess the characteristics of colour removal by Lake Rotorua diatoms.

Vacuum filtration through the diatoms succeeded in removing colour but proved to be impractically slow as an industrial process. Addition of diatoms to wastewater streams in stirred experiments showed that significant adsorption took place. The majority of the colour was removed within 30 seconds of mixing. The efficiency of colour removal was found to vary between wastewater streams within the mills. The pH dependency of this removal was tested and found to be most effective in a pH range of 3.6 to 5.

Attempts to reuse the diatoms showed that chemical backwash regimes were more effective than calcination.

This study concluded that surface silanols were likely to be the principle agent in forming coagulants with the colour material and were subsequently trapped on the diatom surfaces, but more importantly within the pores.

year: 2007

title: Societal expectations for functional recovery of primary and secondary school buildings

authors: Boston, Megan

abstract: In the ongoing investigation of functional recovery requirements, the spectrum of functional requirements for different facility types is necessary to ensure buildings are designed, constructed, and maintained to meet society's expectations. Schools are essential to communities, providing education and shelter to children. Education facilities that remain functional enable the community to recover quickly as parents can return to work or focus on rebuilding. However, functional recovery levels and expectations for schools could be better defined. Using interview responses, this pilot study, focusing on Hamilton, New Zealand, has constructed a five-level functionality continuum for school buildings addressing the societal expectations of community members, including parents, teachers, principals, civil defence, and the ministry of education. The five levels of functionality include life safety, reoccupancy, partial functionality, mostly functional, and fully functional. Each level has been defined in terms of available teaching and community expectations, acceptable damage and infrastructure requirements, and expectations for achievable timelines.

text: Societal expectations for functional recovery of primary and secondary school buildings In the ongoing investigation of functional recovery requirements, the spectrum of functional requirements for different facility types is necessary to ensure buildings are designed, constructed, and maintained to meet society's expectations. Schools are essential to communities, providing education and shelter to children. Education facilities that remain functional enable the community to recover quickly as parents can return to work or focus on rebuilding. However, functional recovery levels and expectations for schools could be better defined. Using interview responses, this pilot study, focusing on Hamilton, New Zealand, has constructed a five-level functionality continuum for school buildings addressing the societal expectations of community members, including parents, teachers, principals, civil defence, and the ministry of education. The five levels of functionality include life safety, reoccupancy, partial functionality, mostly functional, and fully functional. Each level has been defined in terms of available teaching and community expectations, acceptable damage and infrastructure requirements, and expectations for achievable timelines.

year: 2023

title: Paradoxical mobilities: sharemilking with Te Raparahi Lands Trust (Wāotū)

authors: Hutcheson, Gail Yvonne

subjects: mobilities

abstract: Mobilities are important for capturing some of the combined movements of people, animals and objects in all of their complex relational dynamics. Sharemilking involves a cascade of mobilities: from the modest journies of the everyday to the upheaval of complete farm moves. Here we examine how sharemilkers are enabled and constrained in different ways by being mobile and landless, but also included are hopeful geographies. The sharemilker's mobile relationship to land, rather than ownership of it, works well with indigenous ideas of kaitiakitanga (guardianship) that is a central feature of multiply owned Māori land trust (Te Raparahi). Combining sharemilker mobility with te Raparahi, and importantly Ngāti Hūri historical and contemporary connections to Te Wāotū in South Waikato, Aotearoa New Zealand, reveals paradoxical mobilities of place.

text: Paradoxical mobilities: sharemilking with Te Raparahi Lands Trust (Wāotū) Mobilities are important for capturing some of the combined movements of people, animals and objects in all of their complex relational dynamics. Sharemilking involves a cascade of mobilities: from the modest journies of the everyday to the upheaval of complete farm moves. Here we examine how sharemilkers are enabled and constrained in different ways by being mobile and landless, but also included are hopeful geographies. The sharemilker's mobile relationship to land, rather than ownership of it, works well with indigenous ideas of kaitiakitanga (guardianship) that is a central feature of multiply owned Māori land trust (Te Raparahi). Combining sharemilker mobility with te Raparahi, and importantly Ngāti Hūri historical and contemporary connections to Te Wāotū in South Waikato, Aotearoa New Zealand, reveals paradoxical mobilities of place.

year: 2017