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Biomedical subjects

H E Archer

Publications and source records attributed to H E Archer.

6 recordsLinked to original sources
PubMed2005

Improving nitrogen reduction in waste stabilisation ponds.

This paper reviews the performance of two waste stablisation ponds (WSP) systems in the South Island of New Zealand that have been upgraded to multiple ponds-in-series to improve effluent quality. Results of monitoring are provided which show that it is possible to achieve relatively low ammonia (approximately 1 g/m3) and total nitrogen (approximately 10 g/m3) effluent concentrations through the use of nitrification filter beds (rock trickling filters) and sand filters. Evidence suggests that the nitrification and denitrification processes in the extra biofilm surface area provided by the rock filters or rock bank protection is primarily responsible for the improved effluent quality. The paper also compares the WSP results with effluent quality predicted by published formulae. It is concluded that these formulae do not reliably predict the performance of WSP systems and the development of universally applicable design guidelines would be useful.

Ammonia↗
PubMed2003

Waste stabilisation pond developments in New Zealand.

Waste stabilisation ponds have been a popular form of wastewater treatment in New Zealand both for large cities and small communities. Over 100 systems have been constructed ranging in size from over 500 ha to less than 0.1 ha. The largest pond system in New Zealand was at Manukau, Auckland and consisted of four ponds with a total of 530 ha. However, ongoing odour and midge releases and an algae parasite problem plus a requirement to reduce ammonia and total nitrogen in summer, led to the decision to decommission the ponds and allow the area to revert to tidal mudflats. The second largest pond system is at Christchurch and totals 226 ha. In contrast to Manukau, the Christchurch ponds have not caused significant odours and final effluent quality has been good. Christchurch has two parallel trains each with three ponds in series. It is proposed to retain and develop the ponds into a seven cells in series arrangement to reduce short-circuiting. Odour emissions from the Manukau and Christchurch ponds have been measured by the use of olfactometry. Dispersion of odours has been modelled and the extent of "odour travel" determined on a statistical probability basis using actual meteorological data. It can be demonstrated that residential areas can co-exist with ponds, which are not overloaded, with separation distances of 200 metres.

Ammonia↗
PubMed2003

Waste stabilisation ponds upgrading at Blenheim and Seddon, New Zealand--case studies.

Waste stabilisation ponds (WSP) have been a popular form of wastewater treatment in New Zealand both for large cities and small communities. Most WSP were constructed from 1960 to 1985 and were single ponds or a primary and secondary pond in series of similar size. Since 1995, improvements comprising primary and maturation ponds, with four to six cells in series have been constructed or retrofitted to original two cell ponds. The Seddon and Blenheim ponds include in-bank rock filters between maturation cells as a lower cost way of providing this feature for reduction of solids. Operating results show reduced variability in final effluent quality for BOD and SS. In addition, very good reductions of faecal coliform and enterococci have been achieved along with good reductions of ammonia and total nitrogen for most of the year except the middle of winter. Extensive use of rock as rip-rap bank protection and in the rock filters, appears to have provided sufficient extra surface area for a nitrifying biofilm to develop.

Ammonia↗
PubMed2002

Lipoic acid increases glucose uptake by skeletal muscles of obese-diabetic ob/ob mice.

AIM: Alpha-lipoic acid has been reported to increase glucose disposal in diabetic states. This study has examined the effect of alpha-lipoic acid on glucose uptake by cultured L6 muscle cells and different types of skeletal muscles in normal lean (+/+) and severely insulin-resistant, obese-diabetic (ob/ob) mice. METHODS: Glucose uptake was measured in L6 muscle cells using the non-metabolized glucose analogue 2-deoxy-d-glucose (2DG), and in isolated muscles by glucose disappearance from the incubation medium. RESULTS: In L6 muscle cells, short-term incubations (2-12 h) with 10(-3) m alpha-lipoic acid increased glucose uptake by 40-80%, approximately the same extent as 10(-6) m insulin. Combination of the two agents produced a slightly greater increase (120% at 12 h) than either alone. Red quadriceps (mainly type 1 fibres), diaphragm (similar proportions of type 1 and 2 fibres) and abdominal muscle (mainly type 2 fibres) from normal mice incubated with 10(-3) m alpha-lipoic acid showed increased glucose uptake to a similar extent as 10(-6) m insulin in each of the three muscles. Muscles from ob/ob mice, which showed little response to insulin, showed a substantial increase (approximately 300%, p < 0.05-0.01) in glucose uptake when 10(-3) m alpha-lipoic acid was added in the presence of insulin. The alpha-lipoic acid also increased glucose uptake in red quadriceps (approximately 300%, p < 0.01) from ob/ob mice without added insulin. CONCLUSION: The results suggest that alpha-lipoic acid can increase glucose uptake by a range of normal muscle types and improve the response to insulin by insulin-resistant skeletal muscles of ob/ob mice.

Animals↗