Its a chemistry lesson with a difference. The teachers are 1)all ears while their pupils demonstrate an invention they think could help solve Nigerias chronic electricity shortage. Their invention is the ultimate in waste recycling, 2)harnessing the power of pee to make a generator.
Duro-Aina Adebola(student): So we opted for urine. Since, one, its a waste product, and if we use urine as a, in…as a carry out electricities,[sic] and we use urine, our waste products or our exhaust gas is going to be water, and that is not poisonous to our environment.
The system works via an electrolytic cell that breaks the urine down into 3)nitrogen, water and hydrogen. Fourteen-year-old Duro-Aina Adebola is one of four girls at Lagos Doregos Private Academy who devised the generator.
Adebola: This hydrogen oxygen gas mixture goes into our water 4)filter, and the function of the water filter is to remove any 5)impurities from our hydrogen oxygen gas mixture. The hydrogen oxygen gas then goes into a cylinder here, which stores, temporarily stores, the gas whenever we need the gas.
This cylinder contains liquid 6)borax, which purifies the hydrogen making it ready for use. A generator can produce up to six hours of electricity per litre of urine. Their teacher says his pupils have even found a solution to the 7)squeamishness associated with their raw product.
Teacher: (voiceover) You know, people get repelled at the odor of urine. If its their own urine, they dont mind, but somebody elses urine, they dont like touching it. To avoid that they added two 8)molar solution of 9)washing soda at point one percent inside the urine, so it suppresses the odor of the urine.
The 10)quartet, aged between 14 and 15, are hopeful the urine generator will provide an environmentally-friendly energy alternative for the poor. Even though wind and solar energy is harnessed in Nigeria, the options are capital-intensive and not affordable for most rural dwellers. The young innovators have spent just $64.00 on their invention, and believe, with another small investment, they can make the device more 11)compact and more practical in millions of homes throughout the developing world.
這是一堂別開生面的化學(xué)課。學(xué)生們演示自己的發(fā)明時,老師們?nèi)褙炞⒌芈牐瑢W(xué)生認(rèn)為此項發(fā)明能有助于解決尼日利亞長期的“電力缺乏”問題。他們的發(fā)明就是要造一臺能利用尿液的發(fā)電機,這可以說達(dá)到了廢物利用的極致。
杜羅-艾娜·安迪博拉(學(xué)生):我們選擇尿液,因為,它是排泄物,而如果我們把尿液作為發(fā)電的動力,我們使用尿液,最終產(chǎn)生的廢棄物或是廢氣會是水,那就不會對我們的環(huán)境造成污染。
通過電解槽,尿液會分解成氮、水、氫。這個四人小組就讀于拉各斯的多黎戈斯私立學(xué)院,這個想法最初是由14歲的杜羅-艾娜·安迪博拉提出的。
安迪博拉:這類氫氧氣的混合物經(jīng)過過濾器——用來去除混合氣體中的雜質(zhì)元素。接著這樣的氫氧混合氣體到達(dá)這個汽缸中,這是用來儲藏,暫時儲藏氣體的,什么時候我們需要,就從這里取。
這個汽缸裝置里面裝有液態(tài)硼砂,可以純化氫氣以方便使用。這種發(fā)電機利用每公升尿液可以提供長達(dá)六小時的電力。她們的老師說,自己的學(xué)生甚至還為對使用尿液有不適感的人找到了解決方法。
老師:(畫外音)你知道人們對尿液的味道很反感。如果是他們自己的,他們倒不介意,要是是別人的,他們可就不喜歡接觸到了。為了避免異味,她們在尿液中加入了兩摩爾濃度為1‰的洗滌堿溶液,這樣就可以抑制尿液的異味。
這四個女孩年齡介乎14至15歲之間,她們希望這種尿液發(fā)電機可以為窮苦大眾提供一種有利于環(huán)保的能源替代物。盡管尼日利亞也在使用風(fēng)能和太陽能,但它們都屬于資本密集型的能源,大多數(shù)的農(nóng)村民眾負(fù)擔(dān)不起。這些小發(fā)明家的發(fā)明只花費了64美元,而且她們還相信,再多一點投入,她們就能完善裝置,簡易實用,在發(fā)展中國家的萬千家庭普及。
尿液發(fā)電,一個美好的夢想
尿液發(fā)電的原理是通過收集尿液中的氨作為生物燃料來提供能源。來自西英格蘭大學(xué)的研究人員說:“基于每年全球可產(chǎn)生數(shù)萬億公升尿液,這項技術(shù)有助于改變世界能量利用方式。其影響力非常深遠(yuǎn),不僅對于污水處理行業(yè),也使人們對廢水處理產(chǎn)生了新的轉(zhuǎn)換意識?!边@是一個美好的愿景,然而,尿液發(fā)電卻存在致命的缺陷。
一、收益較低:尿液電解產(chǎn)生氫氣需要一種電輸入,就其本身而言尿液在沒有一種現(xiàn)存的能源供應(yīng)的地區(qū)是不能夠被用于發(fā)電的。
二、壽命較短:曼徹斯特大學(xué)的一位研究人員解釋:“尿液不僅是由尿素組成的,其中有很多的鹽,而且鹽水的電解除了產(chǎn)生氫還有氯,氯離子能夠和氫離子結(jié)合形成鹽酸,這不利于發(fā)電機的長期使用?!?/p>
雖然實用性有待商榷,但是,這為人類進(jìn)行廢物利用提出了一個可供參考的途徑。這在人人都喊環(huán)保的今天,切實地想方設(shè)法解決環(huán)境問題還是非常值得贊賞的。