1. 食品工(gong)業廢水分類及水質(zhi)特性 

食品(pin)(pin)(pin)工(gong)(gong)(gong)(gong)(gong)業(ye)(ye)(ye)(ye)(ye)是以(yi)農、牧、漁、林業(ye)(ye)(ye)(ye)(ye)產(chan)(chan)品(pin)(pin)(pin)為主(zhu)要原料(liao)進行加工(gong)(gong)(gong)(gong)(gong)的工(gong)(gong)(gong)(gong)(gong)業(ye)(ye)(ye)(ye)(ye)。食品(pin)(pin)(pin)工(gong)(gong)(gong)(gong)(gong)業(ye)(ye)(ye)(ye)(ye)包括許多與(yu)飲(yin)食有關的行業(ye)(ye)(ye)(ye)(ye)，有不同的分類(lei)方(fang)法(fa)。若按所用(yong)原料(liao)分類(lei)，可分為：肉與(yu)肉制品(pin)(pin)(pin)工(gong)(gong)(gong)(gong)(gong)業(ye)(ye)(ye)(ye)(ye)；禽蛋加工(gong)(gong)(gong)(gong)(gong)工(gong)(gong)(gong)(gong)(gong)業(ye)(ye)(ye)(ye)(ye)；水(shui)(shui)產(chan)(chan)品(pin)(pin)(pin)加工(gong)(gong)(gong)(gong)(gong)工(gong)(gong)(gong)(gong)(gong)業(ye)(ye)(ye)(ye)(ye)；制糖(tang)工(gong)(gong)(gong)(gong)(gong)業(ye)(ye)(ye)(ye)(ye)；水(shui)(shui)果蔬菜加工(gong)(gong)(gong)(gong)(gong)工(gong)(gong)(gong)(gong)(gong)業(ye)(ye)(ye)(ye)(ye)；淀粉工(gong)(gong)(gong)(gong)(gong)業(ye)(ye)(ye)(ye)(ye)；食用(yong)油脂工(gong)(gong)(gong)(gong)(gong)業(ye)(ye)(ye)(ye)(ye)；乳制品(pin)(pin)(pin)工(gong)(gong)(gong)(gong)(gong)業(ye)(ye)(ye)(ye)(ye)；含酒(jiu)精飲(yin)料(liao)工(gong)(gong)(gong)(gong)(gong)業(ye)(ye)(ye)(ye)(ye)；無酒(jiu)精飲(yin)料(liao)工(gong)(gong)(gong)(gong)(gong)業(ye)(ye)(ye)(ye)(ye)；調味品(pin)(pin)(pin)及添(tian)加劑工(gong)(gong)(gong)(gong)(gong)業(ye)(ye)(ye)(ye)(ye)等(deng)。食品(pin)(pin)(pin)加工(gong)(gong)(gong)(gong)(gong)業(ye)(ye)(ye)(ye)(ye)都是以(yi)水(shui)(shui)作為工(gong)(gong)(gong)(gong)(gong)業(ye)(ye)(ye)(ye)(ye)用(yong)水(shui)(shui)和清洗用(yong)水(shui)(shui)。用(yong)水(shui)(shui)量很(hen)大(da)，廢水(shui)(shui)排放量也(ye)很(hen)大(da)。例如，生(sheng)產(chan)(chan)每噸(dun)(dun)(dun)糖(tang)耗(hao)水(shui)(shui)150 t；每噸(dun)(dun)(dun)啤酒(jiu)耗(hao)水(shui)(shui)35 t；每噸(dun)(dun)(dun)罐頭耗(hao)水(shui)(shui)100 t；每噸(dun)(dun)(dun)味精耗(hao)水(shui)(shui)1000 t；每噸(dun)(dun)(dun)飲(yin)料(liao)耗(hao)水(shui)(shui)100 t；每噸(dun)(dun)(dun)酒(jiu)精耗(hao)水(shui)(shui)200 t等(deng)等(deng)。

食品工業廢水主要來(lai)自三個生產工段。

（1）原料(liao)清(qing)洗工(gong)段。大量砂土雜物、葉、皮(pi)、鱗(lin)、肉、羽、毛等進入廢水中，使廢水中含大量懸(xuan)浮物。

（2）生產工段。原料中很(hen)多(duo)成分(fen)(fen)在加工過程中不能(neng)全部利用，未利用部分(fen)(fen)進入廢水，使廢水含大量有機物。

（3）成形(xing)工段。為增(zeng)加(jia)食品色、香、味，延長保存期，使用了(le)各種食品添加(jia)劑，一(yi)部分流(liu)失進入(ru)廢水(shui)，使廢水(shui)化(hua)學成分復雜。

食品廢水(shui)(shui)的水(shui)(shui)量(liang)水(shui)(shui)質特性主要體現(xian)在(zai)6個方面：

（1）廢(fei)水(shui)(shui)量大(da)小不一，食品工(gong)(gong)業(ye)從(cong)家庭工(gong)(gong)業(ye)的小規模到各種(zhong)大(da)型(xing)工(gong)(gong)廠，產(chan)品品種(zhong)繁多(duo)，其原料、工(gong)(gong)藝、規模等差別很大(da)，廢(fei)水(shui)(shui)量從(cong)數m3/d到數千m3/d不等。

（2）生產(chan)隨季(ji)節變化，廢(fei)水水質水量也隨季(ji)節變化。

（3）食品(pin)工(gong)業廢水中(zhong)可(ke)降解(jie)成分(fen)多，對于一般食品(pin)工(gong)業，由(you)于原料來源(yuan)于自然界有(you)機(ji)物質，其廢水中(zhong)的成分(fen)也以自然有(you)機(ji)物質為主，不含有(you)毒物質，故可(ke)生物降解(jie)性好，其BOD5/COD高達0.84。

（4）廢水中(zhong)含各種微生(sheng)物(wu)，包含致(zhi)病微生(sheng)物(wu)，廢水易腐敗發臭。

（5）高(gao)濃(nong)度廢水多。

（6）廢(fei)水中氮、磷含量高。

2．食品(pin)工業廢水處(chu)理(li)方法

2.1  物理處理法

物理(li)(li)處理(li)(li)法是指(zhi)應(ying)用(yong)物理(li)(li)作用(yong)改變廢水成(cheng)分的處理(li)(li)方法。用(yong)于食(shi)品工業廢水處理(li)(li)的物理(li)(li)處理(li)(li)法有篩(shai)濾、撇(pie)除、調(diao)節、沉淀、氣浮(fu)、離(li)心(xin)分離(li)、過濾、微濾等。前(qian)五種工藝(yi)多用(yong)于預處理(li)(li)或(huo)一(yi)級處理(li)(li)，后三(san)種主要(yao)用(yong)于深度處理(li)(li)。

（1）篩濾

篩(shai)(shai)(shai)(shai)濾是(shi)預(yu)處理中(zhong)使用(yong)最廣泛的(de)一種(zhong)方法(fa)。主要作用(yong)是(shi)從廢水(shui)中(zhong)分離出較粗(cu)的(de)分散(san)性懸(xuan)浮固體(ti)物。所(suo)用(yong)的(de)設備(bei)有格(ge)(ge)柵(zha)和格(ge)(ge)篩(shai)(shai)(shai)(shai)。格(ge)(ge)柵(zha)攔截較粗(cu)的(de)懸(xuan)浮固體(ti)，其作用(yong)是(shi)保護(hu)水(shui)泵(beng)和后續處理設備(bei)。食品工業(ye)廢水(shui)中(zhong)常用(yong)的(de)格(ge)(ge)篩(shai)(shai)(shai)(shai)有固定篩(shai)(shai)(shai)(shai)、轉動(dong)篩(shai)(shai)(shai)(shai)和震動(dong)篩(shai)(shai)(shai)(shai)等，格(ge)(ge)篩(shai)(shai)(shai)(shai)最常用(yong)的(de)孔徑是(shi)10—40目。

（2）撇除

某些(xie)食品工(gong)(gong)業廢水中含有大量的(de)油(you)(you)脂，這些(xie)油(you)(you)脂必須(xu)在(zai)進入生(sheng)(sheng)物處(chu)理工(gong)(gong)藝(yi)前予以(yi)除(chu)去，否則會造(zao)成管道、水泵和(he)一(yi)些(xie)設備的(de)堵塞(sai)，還會對生(sheng)(sheng)物處(chu)理工(gong)(gong)藝(yi)造(zao)成一(yi)定(ding)的(de)影(ying)響。此(ci)外，油(you)(you)脂除(chu)去并回(hui)收又有較(jiao)大的(de)經濟價值。

廢水中(zhong)的(de)油(you)(you)脂根據(ju)其(qi)物理(li)狀(zhuang)(zhuang)態(tai)可(ke)(ke)分為游(you)離漂浮狀(zhuang)(zhuang)和(he)乳化狀(zhuang)(zhuang)兩大類。通常隔油(you)(you)池(chi)(chi)除去(qu)漂浮狀(zhuang)(zhuang)油(you)(you)脂。隔油(you)(you)池(chi)(chi)對(dui)漂浮狀(zhuang)(zhuang)油(you)(you)脂的(de)去(qu)處(chu)率可(ke)(ke)達90%以上。如果處(chu)理(li)流程(cheng)中(zhong)設有(you)調節池(chi)(chi)或沉(chen)淀池(chi)(chi)，則隔油(you)(you)池(chi)(chi)可(ke)(ke)與調節池(chi)(chi)或初沉(chen)池(chi)(chi)合(he)用統一構筑(zhu)物，可(ke)(ke)節省投(tou)資和(he)占地(di)。對(dui)小型處(chu)理(li)系(xi)統，可(ke)(ke)設油(you)(you)水分離器撇油(you)(you)。

（3）調節

對(dui)于水(shui)質水(shui)量變化幅度大的(de)(de)食(shi)品工業(ye)廢水(shui)，常設置調節池(chi)對(dui)廢水(shui)的(de)(de)水(shui)質和水(shui)量進行調節，調節時(shi)間一般為6—24h，多為6—12h左右。調節池(chi)容量為日處理廢水(shui)量的(de)(de)15%—50%。

（4）沉淀

沉(chen)(chen)(chen)(chen)(chen)(chen)(chen)(chen)淀(dian)(dian)(dian)是用(yong)(yong)來除(chu)(chu)去(qu)原(yuan)廢水(shui)中(zhong)無機(ji)固(gu)體(ti)(ti)(ti)物(wu)(wu)和有(you)機(ji)固(gu)體(ti)(ti)(ti)物(wu)(wu)，以(yi)及分(fen)離生(sheng)物(wu)(wu)處(chu)理(li)工(gong)藝(yi)中(zhong)的(de)固(gu)相(xiang)和液(ye)相(xiang)。用(yong)(yong)沉(chen)(chen)(chen)(chen)(chen)(chen)(chen)(chen)砂(sha)池除(chu)(chu)去(qu)原(yuan)廢水(shui)中(zhong)的(de)無機(ji)固(gu)體(ti)(ti)(ti)物(wu)(wu)；用(yong)(yong)初沉(chen)(chen)(chen)(chen)(chen)(chen)(chen)(chen)池除(chu)(chu)去(qu)原(yuan)廢水(shui)中(zhong)的(de)有(you)機(ji)固(gu)體(ti)(ti)(ti)物(wu)(wu)；用(yong)(yong)二沉(chen)(chen)(chen)(chen)(chen)(chen)(chen)(chen)池分(fen)離生(sheng)物(wu)(wu)處(chu)理(li)工(gong)藝(yi)中(zhong)的(de)生(sheng)物(wu)(wu)相(xiang)和液(ye)相(xiang)，沉(chen)(chen)(chen)(chen)(chen)(chen)(chen)(chen)砂(sha)池一般(ban)設(she)在(zai)格柵和格篩之(zhi)后。為了清除(chu)(chu)廢水(shui)中(zhong)無機(ji)固(gu)體(ti)(ti)(ti)物(wu)(wu)表面的(de)有(you)機(ji)物(wu)(wu)，避(bi)免(mian)廢水(shui)中(zhong)有(you)機(ji)固(gu)體(ti)(ti)(ti)物(wu)(wu)在(zai)沉(chen)(chen)(chen)(chen)(chen)(chen)(chen)(chen)砂(sha)池中(zhong)產生(sheng)沉(chen)(chen)(chen)(chen)(chen)(chen)(chen)(chen)淀(dian)(dian)(dian)，可(ke)采用(yong)(yong)曝(pu)氣沉(chen)(chen)(chen)(chen)(chen)(chen)(chen)(chen)砂(sha)池。采用(yong)(yong)初沉(chen)(chen)(chen)(chen)(chen)(chen)(chen)(chen)池可(ke)降低(di)后續工(gong)藝(yi)的(de)負荷。初沉(chen)(chen)(chen)(chen)(chen)(chen)(chen)(chen)池除(chu)(chu)去(qu)懸浮固(gu)體(ti)(ti)(ti)的(de)效(xiao)果與加工(gong)的(de)原(yuan)料和產品有(you)關。按池中(zhong)的(de)水(shui)流方向分(fen)為平流沉(chen)(chen)(chen)(chen)(chen)(chen)(chen)(chen)淀(dian)(dian)(dian)池、豎流沉(chen)(chen)(chen)(chen)(chen)(chen)(chen)(chen)淀(dian)(dian)(dian)池、輻流沉(chen)(chen)(chen)(chen)(chen)(chen)(chen)(chen)淀(dian)(dian)(dian)池。為了提高(gao)沉(chen)(chen)(chen)(chen)(chen)(chen)(chen)(chen)淀(dian)(dian)(dian)池的(de)沉(chen)(chen)(chen)(chen)(chen)(chen)(chen)(chen)淀(dian)(dian)(dian)效(xiao)率(lv)，可(ke)在(zai)沉(chen)(chen)(chen)(chen)(chen)(chen)(chen)(chen)淀(dian)(dian)(dian)池內設(she)置平行的(de)斜(xie)(xie)板或斜(xie)(xie)管(guan)而成斜(xie)(xie)板（管(guan)）沉(chen)(chen)(chen)(chen)(chen)(chen)(chen)(chen)淀(dian)(dian)(dian)池。一般(ban)沉(chen)(chen)(chen)(chen)(chen)(chen)(chen)(chen)淀(dian)(dian)(dian)時間1.5—2.0h。

（5）氣浮

氣(qi)浮(fu)主要用于(yu)除去(qu)食品工(gong)業廢水中的(de)乳化油(you)、表面活性(xing)物質和(he)其(qi)他懸浮(fu)固體。有真空式氣(qi)浮(fu)、加壓溶氣(qi)氣(qi)浮(fu)和(he)散氣(qi)管（板）式氣(qi)浮(fu)。當廢水進(jin)入(ru)容器氣(qi)浮(fu)池之(zhi)前，往水中投加化學混凝劑或助凝劑，可提高(gao)乳化油(you)脂和(he)膠體懸浮(fu)顆(ke)粒(li)的(de)去(qu)除率。據資料介(jie)紹(shao)，氣(qi)浮(fu)可除去(qu)90%以(yi)上的(de)油(you)脂和(he)40%—80%的(de)BOD5和(he)SS。氣(qi)浮(fu)池HRT一般30min。

（6）其他處理工藝

對(dui)二級處理出水進行深度處理，常用的(de)方法(fa)是過(guo)濾(lv)(lv)，可采用砂濾(lv)(lv)池或復合濾(lv)(lv)料(liao)濾(lv)(lv)池。按濾(lv)(lv)速(su)(su)大小分慢速(su)(su)砂濾(lv)(lv)池和快濾(lv)(lv)池。一般單層砂濾(lv)(lv)池的(de)濾(lv)(lv)速(su)(su)為(wei)8～12m/h。

2.2  化學處理法

化(hua)學(xue)處(chu)(chu)理法是(shi)指應(ying)用化(hua)學(xue)原理和化(hua)學(xue)作用將廢水(shui)中(zhong)的污(wu)染(ran)物(wu)成(cheng)分轉(zhuan)化(hua)為無(wu)害(hai)物(wu)質(zhi)，使廢水(shui)得(de)到凈化(hua)。污(wu)染(ran)物(wu)在經過化(hua)學(xue)處(chu)(chu)理過程后改變了化(hua)學(xue)本性，處(chu)(chu)理過程中(zhong)總是(shi)伴隨著化(hua)學(xue)變化(hua)。用于食品工業廢水(shui)的化(hua)學(xue)處(chu)(chu)理法有中(zhong)和、混凝、電解、氧化(hua)還原、離子交換、膜分離法等。

（1）混凝法

食品工(gong)業廢水處理(li)(li)中所(suo)用的化學(xue)處理(li)(li)工(gong)藝主要是混(hun)凝法(fa)。混(hun)凝法(fa)不能單獨使用，必須與物理(li)(li)處理(li)(li)工(gong)藝的沉(chen)(chen)淀(dian)(dian)、澄(cheng)清法(fa)或氣(qi)浮(fu)法(fa)結(jie)合使用，構成混(hun)凝沉(chen)(chen)淀(dian)(dian)或混(hun)凝氣(qi)浮(fu)，混(hun)凝沉(chen)(chen)淀(dian)(dian)可(ke)作為生(sheng)物處理(li)(li)的預處理(li)(li)，也(ye)可(ke)作為生(sheng)物處理(li)(li)后的深(shen)度處理(li)(li)。

混(hun)凝(ning)(ning)沉淀法(fa)是(shi)水處理的一個(ge)重要方(fang)法(fa)。對于一些(xie)膠(jiao)體顆粒較(jiao)小、或是(shi)一些(xie)膠(jiao)體溶液，難(nan)以(yi)或不能發生(sheng)沉降的廢(fei)水加入化學混(hun)凝(ning)(ning)劑，使(shi)其形成易于沉降的大(da)顆粒而去除。廢(fei)水中呈膠(jiao)體狀態的蛋白質和多糖類物質，經加藥混(hun)凝(ning)(ning)沉淀即有較(jiao)好的去除效果。

常用(yong)的藥劑(ji)有：石灰、硫酸(suan)亞鐵、三氯化(hua)鐵和(he)硫酸(suan)鋁等。石灰一(yi)般不(bu)單獨使用(yong)，常與其他藥劑(ji)配(pei)合使用(yong)，最佳投藥量(liang)和(he)pH值宜通(tong)過(guo)試(shi)驗確定(ding)。

（2）氧化還原

化(hua)(hua)(hua)學氧(yang)化(hua)(hua)(hua)還原(yuan)是轉(zhuan)化(hua)(hua)(hua)廢水(shui)中污染物的(de)有效方(fang)法。廢水(shui)中呈(cheng)溶解狀(zhuang)態的(de)無機物和有機物，通(tong)過(guo)化(hua)(hua)(hua)學反應被氧(yang)化(hua)(hua)(hua)或(huo)還原(yuan)為微毒(du)或(huo)無毒(du)的(de)物質，或(huo)者轉(zhuan)化(hua)(hua)(hua)成容易與水(shui)分(fen)離(li)的(de)形態，從而(er)達到處理的(de)目的(de)

（3）離子交換

離子(zi)交換(huan)(huan)主要(yao)是(shi)利(li)用離子(zi)交換(huan)(huan)劑對(dui)水中(zhong)存(cun)在的有害(hai)離子(zi)（包括(kuo)有機的及無機的）進行交換(huan)(huan)去(qu)除的方法(fa)。

2.3  生物處理法

生物(wu)化學(xue)處(chu)理(li)法是有機廢水(shui)處(chu)理(li)系統(tong)中最重(zhong)要的(de)(de)(de)過程之(zhi)一。在(zai)食(shi)品工(gong)業的(de)(de)(de)廢水(shui)處(chu)理(li)中，生物(wu)處(chu)理(li)工(gong)藝(yi)(yi)可分為好氧(yang)工(gong)藝(yi)(yi)、厭(yan)氧(yang)工(gong)藝(yi)(yi)、穩定塘、土地處(chu)理(li)以及由上述(shu)工(gong)藝(yi)(yi)的(de)(de)(de)結合而形成的(de)(de)(de)各種各樣的(de)(de)(de)組合工(gong)藝(yi)(yi)。食(shi)品廢水(shui)是有機廢水(shui)，生物(wu)法是主要的(de)(de)(de)二級處(chu)理(li)工(gong)藝(yi)(yi)，目的(de)(de)(de)在(zai)于(yu)降(jiang)解COD、BOD5。

好氧(yang)(yang)生(sheng)(sheng)(sheng)物處理(li)工(gong)藝根據所(suo)利用的微生(sheng)(sheng)(sheng)物的生(sheng)(sheng)(sheng)長(chang)形式分為活性(xing)(xing)污泥(ni)工(gong)藝和膜法(fa)工(gong)藝。前者(zhe)包括傳統活性(xing)(xing)污泥(ni)法(fa)、階段曝氣法(fa)、生(sheng)(sheng)(sheng)物吸附(fu)法(fa)、完(wan)全混(hun)合(he)法(fa)、延時曝氣法(fa)、氧(yang)(yang)化溝、間歇活性(xing)(xing)污泥(ni)法(fa)（SBR）等。后者(zhe)包括生(sheng)(sheng)(sheng)物濾(lv)池(chi)、塔式生(sheng)(sheng)(sheng)物濾(lv)池(chi)、生(sheng)(sheng)(sheng)物轉盤、活性(xing)(xing)生(sheng)(sheng)(sheng)物濾(lv)池(chi)、生(sheng)(sheng)(sheng)物接觸氧(yang)(yang)化法(fa)、好氧(yang)(yang)流化床(chuang)等。一(yi)般(ban)好氧(yang)(yang)處理(li)對低濃度廢水效果(guo)較好。

厭氧(yang)生(sheng)物(wu)處(chu)理(li)工(gong)藝適用于食品工(gong)業(ye)廢(fei)水，主要原因是廢(fei)水中含(han)易生(sheng)物(wu)降解的(de)高濃(nong)度有機(ji)物(wu)，且無(wu)毒性。此外(wai)，厭氧(yang)處(chu)理(li)動力消耗低，產生(sheng)的(de)沼(zhao)氣可(ke)作(zuo)為(wei)能(neng)源(yuan)，生(sheng)成的(de)剩余污泥(ni)量少，厭氧(yang)處(chu)理(li)系統全部(bu)密(mi)閉，利于改善環境衛生(sheng)，可(ke)以季節性或間(jian)歇性運轉，污泥(ni)可(ke)長期儲存(cun)。

3．結束語

總之，在食(shi)品工業(ye)廢水處(chu)理過程中，要根(gen)據不同(tong)的情(qing)況，采取不同(tong)的處(chu)理方(fang)法，這樣才能取得事半功倍的效果。

 參考(kao)文獻：

[1] 唐受印,戴友芝,劉忠義,周作明.食品工業(ye)廢水處理.化學工業(ye)出版社,2001

[2] 李燕城.水處理實驗技術.中國建筑工業出版社,1989
 

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