82 Organic waste recycling: technology and management
Recently, the frozen shrimp production was found to consume 2,400 tons of
shrimp, 980,000 kWh of energy and 78,000 m^3 of water per year. The average
annual production was 1,500 tons of frozen shrimp. By adopting available CP
technology, such as heat exchanger, insulation and equipment modification,
water consumption in the cleaning process was reduced to 55,380 m^3 per year or
a 30% reduction, and energy consumption was reduced up to nearly 50%. Good
house keeping practices were taken for all parts of the production process
(Yolthantham 2002)
Case study B: Birkdale Nursery, Australia
Brikdale Nursery has a reputation of being one of Australia’s leading
ornamental horticultural businesses. It was one of the first nurseries to achieve
ISO certification (ISO 9002: 1994) and was an active participant in the EPA’a
Cleaner Production Partnerships Program.
Increased water charges along with an expansion of the nursery meant that
Brikdale Nursery faced a hefty water bill. The CP assessment made
recommendations to combat excessive water consumption by using alternative
water sources and reuse techniques. Brikdale Nursery has two main sources of
water: town water (at a cost of about 0.7 $/kL) and dam water (leased on
adjacent land for $10,000 per year). The assessment identified two areas where
Brikdale Nursery could reduce water use: collection of run-off water for re-use
and efficient use of water in the plant propagating area. For the first method, the
site has been re-designed to collect run-off for re-use on site. Run-off is
collected, screened, disinfected with chlorine and then re-used to water plants in
the later stages of development. Approximately 35 to 45 percent of the total
water used on the site is now recycled. Water re-use and the use of dam water as
an alternative has cut the treated town water bill by a staggering $2,000 per
week. For the efficient water use, the plant propagation takes place in an
enclosed building monitored for temperature and humidity. This is the only area
that uses treated town water, as the young plants have a high level of sensitivity.
To reduce water use, overhead fine mist sprinklers and capillary watering
systems are now used. The sprinklers are triggered to operate only when the
humidity drops below the desired level. Capillary watering, via mats, delivers
the required amount of water directly to plant roots. A small amount of
additional overhead watering is needed to remove salt from the top of the soil
(www.env.gld.gov.au).