A good keen man
He blew up his fififififififirstfirst methane tank, built a boat in the shape of a saucer, and helped to design a super- super-efficient effififififififificient water blaster, but Coll Bell’s favourite inventions involve manure, and the more, the better.
Coll Bell is an inventor, the proper, old-fashioned type who’s never happier than when tinkering in his capacious shed. His favourite line is “I’ve got a cunning plan!” and one of his most profitable cunning plans to date is in our back garden, full of busy worms composting everything we flush down our loo.
He’s also invented the perfect ‘short drop’ loo, a sailing saucer, and an arkshaped sleep-out that’s bigger than 10m² but doesn’t require council permission.
But it’s his latest wastewater project that may be a game-changer and a way for dairy farmers to help save the planet.
Coll (64) is fairly well known in the poo business. His first experiments in trying to make something positive out of ones and twos dates back to the late 1980s. He had the idea of harvesting methane gas for his self-sufficient lifestyle and created a polystyrene tank coated in concrete which was connected to the toilet. But one dark and stormy night there was an almighty explosion and a terrible smell. The less said, the better says Coll.
Undeterred, he tried again. The catalyst this time was that his home was at the bottom of a cliff and to pump poo up it to the town supply sewage system was a pain. He figured out a way to separate solids from liquids and just pumped the dirty water up the cliff, while worms dealt
to the solids. This formed the basis of his first commercial product, the Natural Flow system, which he built up and then sold.
He’s run his latest company, Simple Waste Water Solutions, for the past 10 years and his latest alternative to the septic tank is the end product of his years of experience in sustainable waste management. In his humble opinion, it’s pretty perfect.
The system comprises three components. The first is a solid waste digester, a 1.2m moulded plastic tank where a colony of tiger worms recline on a bed of bark and sawdust, ready to munch through kitchen and toilet waste. The digester is easily cleaned out, about every
two years for a family of four.
Grey water from the shower, bath and washing machine goes straight into a much smaller mixing tank where it meets any black water that comes through the solid waste digester. The combined water is then returned to an aerobic state by filtering it through the second component, a series of bark and sawdust-filled tubs planted with a variety of greenery, including native grasses such as Carex virgata. The root systems of the plants grow good bacteria, and the bark and sawdust suck up nitrogen.
The filtered water that comes out at the end of this process goes into a small dosing tank, the third and final component. This simply regulates the discharge, and can be attached to a hydroponic tunnel house which ensures nil discharge of the treated water. You can also opt for a slow release scenario, drip-feeding it around your garden if it’s on a bit of a slope. If not, a solar-powered pump can move things along.
Selling and installing this system keeps him and his sonin-law pretty busy for most of the year, but Coll isn’t satisfied with small scale projects. The logical extension is found at the busy heart of the dairy farms that surround him on his small block north of Auckland. Every cowshed produces a huge amount of wastewater every day, and Coll’s Clean Cow dairy effluent disposal system is nothing less than his watersaving vision for the future of the dairy industry.
In developing his newest invention, Coll looked at the amount of water used during a typical milking, the run-off into streams, and the need to recycle a cleaner product (and a valuable by-product) back into the environment. Clean Cow’s concept is the same as the one for his septic tanks, but it’s bigger. A lot bigger.
Coll used outside funding to set up a trial on a neighbour’s dairy farm. It has 230 milking cows, and there was enough room for Coll to work around the existing set-up.
A mate who runs a rotational plastics business created a 1.6m radius quarter-tank mould which can be clear or dark green. As with many of Coll’s inventions, it works on a number of levels: • when lying flat, it is the Clean Cow decanting tanks; • when cut in half, it can become a solid waste digester; • clear ones on their sides can be used as tunnel houses. The water used to wash down the cowshed is directed into the decanting tanks on a rotating basis. Once it settles, liquid is drained off to the plant filters. Any other water bypasses the decanting tanks and goes straight to the filters. The filtered water, full of nutrients, can be stored and sprayed on to the paddocks. The solids caught by the filter are processed by tiger worms which produce a rich, crumbly vermicast compost, which can be bagged and sold.
Part of the success of this plant is due to a cowshedcustomised water blaster Coll has designed with a German company which makes significant water savings. The water blaster is not compulsory for the Clean Cow system, however projected future droughts mean every drop in future will become more precious. There’s also the possibility that any permitted activity in a waterway with a meter that’s overused will incur fines, so there will soon be a monetary incentive to save water.
Coll’s test farmer was a convert, using it to wash down the plant, and the tractor and ride-on.
The results were just what Coll was hoping for: water usage went from 10,000 litres per milking, down to just over 2000 litres, a 75% saving.
The trial set-up was also used to gauge how much liquid and solids a herd of 230 cows can produce in a standard herringbone shed over the course of a few months. As a result, Coll redesigned the system to have a 2.4m radius quarter tank, with four of them giving a farmer a 32,000 litre capacity decanting tank. However, Coll’s system is flexible so a farmer can add in as many tanks as required for the number of milking cows on a farm.
Like all inventions, it’s going to require more money, so Coll is now looking for someone to both invest and run the business side of things so he can concentrate on getting the formula right. As well as getting on with his next invention, of course.