Ecosan in NZ? Sanitation Case Studies: NZ & Raratonga 1.1

Transcription

1 Ecosan in NZ Sanitation Case Studies: NZ & Raratonga Appropriate sanitation for the developing world The Norwegian University of Life Sciences August 14-18, 2006 Constructed wastewater wetlands Land application of treated/untreated wastewater mostly agricultural waste but also domestic, especially small onsite system Composting loos Greywater re-use Urine separation Prepared by Andrew Dakers, ecological wastewater Engineer, Christchurch., New Zealand EM is the abbreviation of Effective Microorganisms, originated by Dr. Teruo Higa, Japan. It is a mixed microbial culture of selected species of microorganisms such as lactic acid bacteria, yeasts, photosynthetic bacteria and actinomycetes. All of these are mutually compatible with one another and coexist in liquid culture

2 Vermicaste poo cam 14 days What is topsoil An complex, evolving, dynamic microecosystem of minerals, organics, living fibre, micro-organisms, water and air. A teaspoon of topsoil would have around 100 million bacteria and fungal threads of around 1.5 km in length (Molloy, 1993)

3 Spores partly covered by clay and humic substances Soil formation Current food and fibre producing topsoil has slowing built up over several million years of physical, biological and chemical processes. Gondwanaland is over 80 mill years old Podocarp/hardwood forest Polysaccharide strands and colonies of bacteria Hypha of an actinomycete A protozoan showing jaws From: Soils in the NZ Landscape; the living mantle, by Les Molloy, As time passed, soils were influenced by the forest environment: rain percolating through the canopy and forest floor litter dissolved soluble elements out of the soil; a specialised soil fauna including insects, spiders, worms and micro-organisms, developed in the decaying litter each playing a role in transforming into soil organic matter (humus) and nutrients available to plants. From Molloy, In New Zealand fertile forest soils were converted to agricultural land use. Airtech, RSX Plastics Artists impression of living organisms under a grass/clover pasture. Biolytix, BF6 Molloy 1998 From Molloy, Installing dripper lines

4 Cooks Island about 4hr flight north 0f New Zealand a self-governing parliamentary democracy in free association with New Zealand 15 small islands in this South Pacific Ocean population: 21, ,000 visitors/day small islands Rarotonga 67 sq km About 1200 permanent residence 100,000 tourists/yr ~ 2100 mm annual RF Sanitation practices in Raro. Location of tourist accommodation - Nearly all are on-site systems - Septic tank to soak pit - Some advanced treatment for larger commercial tourist operations

5 Too much organic matter Lyngbya sp. Algae bloom, Vaima anga, Pathogens in water Lagoon ecological system: key components Frequent high intensity rainfall Steep terrain: rain forest Shallow Lagoon Wetlands Pacific Groundwater Coral sands: rapid drainage Clays: very poor drainage Lagoon ecological system: impact of development Impact on the ecosystem and its services Frequent high Removal of some rain forest; intensity rainfall Removal of wetlands; Hard surfaces roading, paving, roofs decreases permeability, increases surface runoff; Steep terrain: Fertliser and chemicals added through horticulture and agriculture; rain forest Contaminated point discharges eg. ; septic tank soak holes Shallow discharging to groundwater, Lagoon wastewater treatment plant discharges to surface and ground water (including from commercial Groundwater piggeries). Clays: very poor drainage Pacific Stormwater outlets. Coral sands: rapid drainage Contamination of drinking water. Fragmentation of land and marine habitats. Loss of biodiversity. 29 Two contrasting soil profiles Stoney coral sand (Muri) excessively drained. Tikioki soil which is described as moderately drained

6 Soils map showing variability for soils each soil type will have different mineral content and hydraulic properties this (along with rainfall events, subsurface geological structures and ground slope) affects the behaviour of the hydraulic links between land based activities and lagoon ecology Flush Toilet, Septic Tank, Free-draining soils Ground water table 31 Slide design by Jacqui Evans Groundwater contamination 32 Flush Toilet, Septic Tank, Clay soils Surface exposure Septic tank to soakage trench (to AS/NS1547) would be about $ $8000 and would require 400 m of trench Ground water table Secondary treatment to subsurface irrigation (to AS/NZS1547) would be about $10,000 - $13,000 and would require 420 m 2 of subsurface irrigation area. Slide design by Jacqui Evans

7 Projects objectives Improve sanitation to: Protect public health Protect lagoon 37 Obstacles Lack of in-country capacity high vulnerability to plausible pseudo-experts. Very little interagency communication/cooperation. Inadequate regulations Attitudinal Personal responsibility it s the Governments problems. Expectation of simple technological fix. Can t afford high tech systems V-high energy costs Soils. Limited area available for dispersal 38 Strategy: integrated multi level approach Policy and regulations Institutional strengthening Training regulators, engineers, plumbers/drainlayers Upgrade existing and new sanitation practices and technologies Pilot study: Ecosystem management of lagoon Community/village participation The challenge - How to reduce/eliminate wastewater N emission to lagoon in a away that is: Affordable to the owner of the dwelling Easy to service Acceptable culturally Sustainable R&D Domestic Commercial end Coastal sandy soils Benefits of urine separation Inland heavy clays Men have to sit; reducing risk of damage to vital parts!!