Large centralized trash-to-energy plants are built on a model that imitates the status quo - central plant, collection system for raw material that is reliant on truck pick-up/delivery and a distribution method by wire, pipe, truck or rail. As a management system for both "trash" pick-up and energy production, centralized systems require a large amount of energy use, with resulting pollution, for moving things around.
Centralized energy production also is an incredibly efficient system for the redistribution of wealth. Basically, the purchase of energy never stops - we all need it.Yet it is a product that vanishes at the moment we acquire it - yes we get something, lets say cooked food, that is essential to our well being, but in a few hours, or the next morning we will need more.
Imagine instead a system that does not require the purchase of energy because the energy is now locally produced by the user themselves utilizing what they have previously thrown away - things that previously they had to pay to have taken away! A variety of savings appear - both to the individual user and to the larger society. Most immediately for the user is a reduction or elimination of paying for energy. Further, if energy production is brought to the house or building level, the means of energy production - solar collector or bio-gas generator for example - increase the value of the building they are attached to. Now instead of paying out for energy, money is saved and the value of most people's biggest asset - their house - increases.
Following is a story from The Banaglore Mirror (India) about one family and their bio-digester -
SELF HELP IS BEST HELP
Nine gas cylinders a year rule does not apply to him
Posted On Monday, July 29, 2013
It’s a problem that has generated more than a
whiff of unpleasantness. While most of us ranted and suffered as the
garbage kept piling up right outside our doorstep, with contractors
refusing to carry out door-to-door collection, a Banashankari resident
did what a true civic-minded citizen would have done.
To begin with, he complained to the BBMP commissioner. But after
three complaints went unheeded, Satish Bakshi decided not to waste any
more time and do it himself. And he came up trumps! Bakshi’s efforts
have paid off and today, he and his family savour the sweet smell of
success as their indigenously made bio-gas plant lights the kitchen fire
thrice a week, and also keeps their vegetable and fruit garden verdant
and bountiful.
Bakshi says he watched the garbage assume menacing proportions with
every passing day, and it finally struck him that he could extract gas
out of it. With the internet as his teaching aid, and a plastic water
tank, a useless tyre and other ordinary devices to fuel his dream, he
embarked on the project.
SURFING FOR IDEAS
An independent tax consultant, Bakshi tapped the internet for
ideas. “I read that the concept of converting garbage into gas had
caught on in Pune and Kochi. Since I was setting up my bio-gas plant in a
residential area, I needed to avoid foul smell and ensure disposal of
residue (slurry) within minimum space and with limited funds. The
methods suggested on line were for a full-fledged bio-gas plant which I
couldn’t have set up. But taking a leaf out of those ideas, I thought
of experimenting with a plastic water drum installed on my roof,” Bakshi
told Bangalore Mirror.
Bakshi’s next step was to put the ubiquitous black water drum to
ingenious use. He converted it into a digester tank to generate pure
methane and installed a pipeline leading to his kitchen.
Bakshi says he had a plastic tank on the terrace of his house with a
capacity of 1,000 litres. “I bought another similar tank of 750-litre
capacity. After making a small partition inside the bigger tank to hold
the garbage, I inverted the smaller tank upon it, covering the
partition. To facilitate the insertion of garbage, a medium-sized
opening was made at the centre of the inverted tank. A small hole was
drilled on the periphery of the same tank and was fitted with a valve
and pipeline to supply the methane gas produced,” he explained.
NEIGHBOURS GOT NO WHIFF
With a gas digester in place, Bakshi poured the garbage into it in
the first week of April. Though their experiment had been flagged off,
the entire family was on tenterhooks, plagued by fears of the foul smell
causing a nuisance to neighbours, especially because it would be nearly
45-50 days before the gas could be produced since the garbage needs
time to completely decompose before it can produce methane. “However, no
one in the neighbourhood will believe it if I tell them that I have set
up a gas digester atop my house. You will not be able to smell any
stench unless you peep into the tank.”
He says once the gas is collected inside the inverted tank, it
begins to rise — an indicator that it’s ready to be tapped. To tap gas,
you need to apply pressure on top of the tank so that it pushes the gas
through the pipeline. Once again, Bakshi’s innovations came into play.
“To exert pressure, I used a waste tyre of my car and a small boulder.
It worked, and I managed to easily pump the gas through the pipe,” he
explained.
Their moment of glory could not have been better timed. On June 5,
World Environment Day, Bakshi says they could smell methane in the tank.
“On that day, I just turned on the valve and held a lighted matchstick
to test if it would work. The first sight of the dark blue flame sparked
off celebrations in our home,” says Bakshi, adding that very evening
they prepared their coffee with the gas from their plant. Though the
quantity was very low at first, it improved with every passing day.
“Now, we get about two to three hours of constant supply thrice a week,
depending on the amount of garbage,” he says.
EVEN THE RESIDUE COUNTS
The solid garbage put into the tank turns into a slurry residue
after the extraction of gas. Bakshi has found good use of the residue
too. An outlet flushes out the liquid that finds its way into his
terrace garden. “I have been growing pineapple, mango, some vegetables,
spinach and banana on the rooftop,” he says.
Though they don’t have enough garbage to generate gas on a daily
basis, Bakshi says homes that produce 5-6 kg garbage every day can cook
using bio-gas and cut down on LPG usage. However, since the gas doesn’t
come at great pressure, the burners need to have bigger holes.
Sharing their experiences, Bakshi and his wife, K Aravindavalli,
caution against putting seeds of fruits like jackfruit or mango and
chicken bones. “If the substance is hard, it will take several months to
decompose. Anything that does not decompose will remain at the bottom
and eat up space. So, irrespective of the waste, cut it into small
pieces, give it a rinse with water and pour into the tank,”
Aravindavalli says.
The entire set-up has cost the Bakshis less than Rs 20,000. “It
could have been lesser, but since I was doing it on a trial-and-error
method, I incurred some extra expenditure,” he says, adding that if BBMP
or state government helps with subsidy, a bio-gas plant would be a
viable alternative for every household.
A SECRET RECIPE
Thanks to his constant innovation and experimentation, Bakshi
reveals he has concocted a mixture of certain organic products which he
adds into the garbage tank for speedy fermentation. While he is keeping
the recipe a closely guarded secret, he is willing to supply the powder
at a nominal rate.
Meanwhile, garbage collection has resumed since last month, but the
Bakshi household is no longer dependent on the system. Before starting
the project in April, he had approached the BBMP, assuming he needed
permission for the bio-gas plant. But he was told there was no such
provision, and he could go ahead with it if it did not harm neighbours.
Copyright 2009 Bennett Coleman
& Co. Ltd. . All rights reserved.
