城(cheng)市垃(la)圾(ji)(ji)(ji)分(fen)類收(shou)(shou)集并(bing)不陌生，比如大部分(fen)居民在家庭中對(dui)舊報紙、易拉(la)罐等還是基本做到單(dan)獨收(shou)(shou)集，然(ran)后(hou)賣給“回收(shou)(shou)工”。然(ran)而(er)沒(mei)有一(yi)個城(cheng)市或(huo)地區能(neng)夠給出(chu)可回收(shou)(shou)垃(la)圾(ji)(ji)(ji)數量、種(zhong)類以及(ji)回收(shou)(shou)利(li)用(yong)的(de)去向等明確(que)的(de)數據，客(ke)觀認(ren)識垃(la)圾(ji)(ji)(ji)回收(shou)(shou)利(li)用(yong)，或(huo)可有效推進垃(la)圾(ji)(ji)(ji)處理(li)的(de)進程。

　　垃(la)圾的含義實際(ji)上就(jiu)是廢棄無用(yong)的東(dong)西，所有的物品(pin)在完成其使用(yong)壽命(ming)后(hou)，最終的歸(gui)宿就(jiu)成為(wei)垃(la)圾，因此，垃(la)圾在它誕生時(shi)的條件就(jiu)是無用(yong)或低價值。

　　垃圾回收(shou)利(li)(li)用(yong)(yong)(yong)(yong)有(you)(you)以下幾(ji)種類型：第(di)一(yi)個層(ceng)次(ci)(ci)是直接(jie)回收(shou)利(li)(li)用(yong)(yong)(yong)(yong)并(bing)保(bao)持(chi)(chi)(chi)(chi)其(qi)原(yuan)有(you)(you)的(de)(de)使(shi)用(yong)(yong)(yong)(yong)功能(neng)，如將啤酒瓶等(deng)(deng)經過清洗后重新(xin)作為啤酒瓶使(shi)用(yong)(yong)(yong)(yong)，舊衣服、二手物品使(shi)用(yong)(yong)(yong)(yong)等(deng)(deng)。回收(shou)利(li)(li)用(yong)(yong)(yong)(yong)的(de)(de)第(di)二個層(ceng)次(ci)(ci)是不(bu)再(zai)(zai)保(bao)持(chi)(chi)(chi)(chi)其(qi)原(yuan)有(you)(you)的(de)(de)形(xing)態和使(shi)用(yong)(yong)(yong)(yong)性(xing)(xing)能(neng)，但(dan)還(huan)保(bao)持(chi)(chi)(chi)(chi)利(li)(li)用(yong)(yong)(yong)(yong)其(qi)材料的(de)(de)基本(ben)性(xing)(xing)能(neng)，如廢紙再(zai)(zai)生(sheng)、玻璃再(zai)(zai)生(sheng)等(deng)(deng)。回收(shou)利(li)(li)用(yong)(yong)(yong)(yong)的(de)(de)第(di)三個層(ceng)次(ci)(ci)是不(bu)再(zai)(zai)保(bao)持(chi)(chi)(chi)(chi)其(qi)原(yuan)有(you)(you)的(de)(de)形(xing)態、使(shi)用(yong)(yong)(yong)(yong)性(xing)(xing)能(neng)和材料的(de)(de)基本(ben)性(xing)(xing)能(neng)，但(dan)還(huan)保(bao)持(chi)(chi)(chi)(chi)利(li)(li)用(yong)(yong)(yong)(yong)其(qi)部(bu)分分子特性(xing)(xing)等(deng)(deng)，如生(sheng)物質有(you)(you)機垃圾的(de)(de)堆肥。還(huan)有(you)(you)一(yi)種形(xing)式的(de)(de)回收(shou)利(li)(li)用(yong)(yong)(yong)(yong)通(tong)常沒有(you)(you)納入(ru)回收(shou)利(li)(li)用(yong)(yong)(yong)(yong)范疇，就是不(bu)再(zai)(zai)保(bao)持(chi)(chi)(chi)(chi)其(qi)原(yuan)有(you)(you)的(de)(de)形(xing)態、性(xing)(xing)能(neng)，而利(li)(li)用(yong)(yong)(yong)(yong)其(qi)分解(jie)合(he)成(cheng)過程中(zhong)產生(sheng)的(de)(de)能(neng)源或(huo)新(xin)材料，如垃圾焚燒的(de)(de)余熱(re)利(li)(li)用(yong)(yong)(yong)(yong)、填埋氣體的(de)(de)回收(shou)等(deng)(deng)。

　　生活垃(la)圾(ji)管(guan)理(li)的戰(zhan)略與技術路線是減量化、資(zi)源化、無害(hai)化。首先是盡(jin)(jin)可(ke)(ke)能避(bi)免產生；其(qi)(qi)次是盡(jin)(jin)可(ke)(ke)能進(jin)行回收利(li)用(yong)(yong)，其(qi)(qi)中盡(jin)(jin)可(ke)(ke)能對可(ke)(ke)生物(wu)降解(jie)的有機(ji)(ji)物(wu)進(jin)行堆(dui)肥處(chu)(chu)理(li)或厭氧(yang)消化處(chu)(chu)理(li)，有機(ji)(ji)垃(la)圾(ji)的循環利(li)用(yong)(yong)屬于回收利(li)用(yong)(yong)范疇；再其(qi)(qi)次盡(jin)(jin)可(ke)(ke)能對可(ke)(ke)燃物(wu)進(jin)行焚燒處(chu)(chu)理(li)并余(yu)熱利(li)用(yong)(yong)；最(zui)后是對不能進(jin)行其(qi)(qi)他處(chu)(chu)理(li)的垃(la)圾(ji)進(jin)行填埋處(chu)(chu)理(li)。

　　為什(shen)么不(bu)能把垃圾全部進行(xing)利(li)用，其原因是(shi)當利(li)用成(cheng)本很高時就不(bu)必再利(li)用了。盡可能利(li)用的重要前提就是(shi)經(jing)濟因素。

　　內地(di)生(sheng)活垃圾實際回收利用(yong)總體水(shui)平(ping)高于任何一個發達國(guo)家(jia)，卻沒(mei)有一個城(cheng)市或(huo)地(di)區(qu)能(neng)夠(gou)給出可回收垃圾數量、種類以(yi)及回收利用(yong)的去向等(deng)明確(que)的數據，主要原因是(shi)底(di)數不(bu)清、目標不(bu)明、缺乏(fa)經濟(ji)調節手段、缺乏(fa)責任主體。