怎樣健康飲水?
來源(yuan):鞏義市(shi)美源(yuan)凈水材料有(you)限公(gong)司 閱讀:1905 更新時間:2012-03-11 22:421. 食品工業廢水(shui)分類及水(shui)質(zhi)特(te)性(xing)
食(shi)品(pin)工(gong)(gong)(gong)(gong)(gong)業(ye)是以農(nong)、牧、漁(yu)、林業(ye)產品(pin)為(wei)主要原(yuan)料(liao)(liao)進行加(jia)工(gong)(gong)(gong)(gong)(gong)的工(gong)(gong)(gong)(gong)(gong)業(ye)。食(shi)品(pin)工(gong)(gong)(gong)(gong)(gong)業(ye)包括許(xu)多與(yu)飲(yin)(yin)食(shi)有關的行業(ye),有不(bu)同的分類方法(fa)。若按(an)所用(yong)原(yuan)料(liao)(liao)分類,可(ke)分為(wei):肉與(yu)肉制品(pin)工(gong)(gong)(gong)(gong)(gong)業(ye);禽蛋加(jia)工(gong)(gong)(gong)(gong)(gong)工(gong)(gong)(gong)(gong)(gong)業(ye);水(shui)(shui)產品(pin)加(jia)工(gong)(gong)(gong)(gong)(gong)工(gong)(gong)(gong)(gong)(gong)業(ye);制糖工(gong)(gong)(gong)(gong)(gong)業(ye);水(shui)(shui)果蔬菜加(jia)工(gong)(gong)(gong)(gong)(gong)工(gong)(gong)(gong)(gong)(gong)業(ye);淀粉(fen)工(gong)(gong)(gong)(gong)(gong)業(ye);食(shi)用(yong)油脂工(gong)(gong)(gong)(gong)(gong)業(ye);乳制品(pin)工(gong)(gong)(gong)(gong)(gong)業(ye);含酒(jiu)(jiu)(jiu)精(jing)(jing)飲(yin)(yin)料(liao)(liao)工(gong)(gong)(gong)(gong)(gong)業(ye);無酒(jiu)(jiu)(jiu)精(jing)(jing)飲(yin)(yin)料(liao)(liao)工(gong)(gong)(gong)(gong)(gong)業(ye);調味品(pin)及添(tian)加(jia)劑工(gong)(gong)(gong)(gong)(gong)業(ye)等。食(shi)品(pin)加(jia)工(gong)(gong)(gong)(gong)(gong)業(ye)都是以水(shui)(shui)作為(wei)工(gong)(gong)(gong)(gong)(gong)業(ye)用(yong)水(shui)(shui)和清(qing)洗用(yong)水(shui)(shui)。用(yong)水(shui)(shui)量很(hen)大(da),廢水(shui)(shui)排(pai)放(fang)量也很(hen)大(da)。例如(ru),生產每(mei)(mei)噸(dun)糖耗(hao)(hao)水(shui)(shui)150 t;每(mei)(mei)噸(dun)啤(pi)酒(jiu)(jiu)(jiu)耗(hao)(hao)水(shui)(shui)35 t;每(mei)(mei)噸(dun)罐頭耗(hao)(hao)水(shui)(shui)100 t;每(mei)(mei)噸(dun)味精(jing)(jing)耗(hao)(hao)水(shui)(shui)1000 t;每(mei)(mei)噸(dun)飲(yin)(yin)料(liao)(liao)耗(hao)(hao)水(shui)(shui)100 t;每(mei)(mei)噸(dun)酒(jiu)(jiu)(jiu)精(jing)(jing)耗(hao)(hao)水(shui)(shui)200 t等等。
食(shi)品工業廢(fei)水主要來自三個生(sheng)產工段(duan)。
(1)原料清洗(xi)工段。大量砂土(tu)雜物(wu)、葉、皮、鱗(lin)、肉、羽、毛等進入廢(fei)水中(zhong),使廢(fei)水中(zhong)含(han)大量懸浮物(wu)。
(2)生產工段。原料中很(hen)多成分(fen)(fen)在加工過(guo)程中不能(neng)全部利用(yong),未利用(yong)部分(fen)(fen)進入廢(fei)水(shui),使廢(fei)水(shui)含大量有(you)機物。
(3)成(cheng)形工段。為增(zeng)加食(shi)(shi)品(pin)色、香、味,延長保存期,使(shi)(shi)用了各種食(shi)(shi)品(pin)添加劑,一部分流失(shi)進入廢水(shui),使(shi)(shi)廢水(shui)化學成(cheng)分復雜。
食品廢水的水量水質(zhi)特性主(zhu)要(yao)體(ti)現在6個方面:
(1)廢水量(liang)大小不一(yi),食品(pin)工業(ye)(ye)從家庭工業(ye)(ye)的小規模到各種大型工廠,產品(pin)品(pin)種繁多,其原(yuan)料(liao)、工藝、規模等(deng)差(cha)別很大,廢水量(liang)從數m3/d到數千m3/d不等(deng)。
(2)生產隨(sui)季節變化(hua)(hua),廢(fei)水水質水量也隨(sui)季節變化(hua)(hua)。
(3)食品工業廢水中可降解成分(fen)多,對(dui)于一般食品工業,由于原料來源于自然界有(you)機物(wu)質,其(qi)廢水中的成分(fen)也以自然有(you)機物(wu)質為主(zhu),不含有(you)毒物(wu)質,故可生物(wu)降解性好,其(qi)BOD5/COD高達0.84。
(4)廢水中含各(ge)種(zhong)微生物(wu)(wu),包含致病微生物(wu)(wu),廢水易腐敗發臭。
(5)高濃度(du)廢水多。
(6)廢(fei)水中氮、磷(lin)含量高(gao)。
2.食品(pin)工業廢水處理方(fang)法
2.1 物理處理法(fa)
物理(li)(li)處理(li)(li)法(fa)是指應用(yong)(yong)物理(li)(li)作用(yong)(yong)改變廢(fei)(fei)水(shui)(shui)成分的(de)處理(li)(li)方法(fa)。用(yong)(yong)于(yu)食品工業(ye)廢(fei)(fei)水(shui)(shui)處理(li)(li)的(de)物理(li)(li)處理(li)(li)法(fa)有篩濾、撇除、調節(jie)、沉(chen)淀(dian)、氣浮、離(li)心分離(li)、過濾、微濾等。前(qian)五(wu)種工藝(yi)多用(yong)(yong)于(yu)預處理(li)(li)或一(yi)級處理(li)(li),后三種主要用(yong)(yong)于(yu)深(shen)度(du)處理(li)(li)。
(1)篩濾
篩(shai)(shai)濾是預處理中(zhong)(zhong)使用最廣泛的(de)一種(zhong)方法。主要作用是從(cong)廢水(shui)中(zhong)(zhong)分離出較粗的(de)分散性懸(xuan)(xuan)浮固體物。所用的(de)設(she)備有格柵和格篩(shai)(shai)。格柵攔截較粗的(de)懸(xuan)(xuan)浮固體,其作用是保護(hu)水(shui)泵和后續處理設(she)備。食品工業廢水(shui)中(zhong)(zhong)常用的(de)格篩(shai)(shai)有固定篩(shai)(shai)、轉動(dong)篩(shai)(shai)和震動(dong)篩(shai)(shai)等(deng),格篩(shai)(shai)最常用的(de)孔徑是10—40目。
(2)撇除
某些食品工業廢水中含有(you)大量的油脂,這些油脂必須在進入生物(wu)處(chu)理(li)工藝(yi)前予以除(chu)去(qu),否則(ze)會造成(cheng)管道(dao)、水泵和一(yi)些設備(bei)的堵塞,還會對生物(wu)處(chu)理(li)工藝(yi)造成(cheng)一(yi)定的影響。此外,油脂除(chu)去(qu)并(bing)回(hui)收又有(you)較大的經濟價(jia)值(zhi)。
廢水中(zhong)的油(you)(you)(you)脂根據其物理狀(zhuang)態(tai)可(ke)(ke)分為游離漂浮狀(zhuang)和乳(ru)化狀(zhuang)兩大類。通常隔油(you)(you)(you)池(chi)(chi)除去漂浮狀(zhuang)油(you)(you)(you)脂。隔油(you)(you)(you)池(chi)(chi)對(dui)漂浮狀(zhuang)油(you)(you)(you)脂的去處(chu)率可(ke)(ke)達90%以(yi)上。如果處(chu)理流程中(zhong)設有調節池(chi)(chi)或(huo)沉淀池(chi)(chi),則(ze)隔油(you)(you)(you)池(chi)(chi)可(ke)(ke)與調節池(chi)(chi)或(huo)初沉池(chi)(chi)合用(yong)統(tong)(tong)一構(gou)筑物,可(ke)(ke)節省投資(zi)和占地。對(dui)小(xiao)型處(chu)理系統(tong)(tong),可(ke)(ke)設油(you)(you)(you)水分離器撇油(you)(you)(you)。
(3)調節
對于水質水量變(bian)化幅度大的(de)(de)食品工業(ye)廢(fei)(fei)水,常(chang)設置(zhi)調節池對廢(fei)(fei)水的(de)(de)水質和水量進行調節,調節時間(jian)一般為6—24h,多為6—12h左右。調節池容量為日處理廢(fei)(fei)水量的(de)(de)15%—50%。
(4)沉淀
沉(chen)(chen)淀(dian)是用來(lai)除去原廢(fei)水(shui)中(zhong)無機(ji)(ji)固(gu)體(ti)物(wu)(wu)(wu)和(he)有(you)機(ji)(ji)固(gu)體(ti)物(wu)(wu)(wu),以及(ji)分離生(sheng)物(wu)(wu)(wu)處理工(gong)(gong)藝中(zhong)的固(gu)相(xiang)(xiang)和(he)液相(xiang)(xiang)。用沉(chen)(chen)砂池(chi)(chi)(chi)除去原廢(fei)水(shui)中(zhong)的無機(ji)(ji)固(gu)體(ti)物(wu)(wu)(wu);用初沉(chen)(chen)池(chi)(chi)(chi)除去原廢(fei)水(shui)中(zhong)的有(you)機(ji)(ji)固(gu)體(ti)物(wu)(wu)(wu);用二(er)沉(chen)(chen)池(chi)(chi)(chi)分離生(sheng)物(wu)(wu)(wu)處理工(gong)(gong)藝中(zhong)的生(sheng)物(wu)(wu)(wu)相(xiang)(xiang)和(he)液相(xiang)(xiang),沉(chen)(chen)砂池(chi)(chi)(chi)一(yi)般(ban)設在格(ge)柵(zha)和(he)格(ge)篩之(zhi)后。為(wei)了清除廢(fei)水(shui)中(zhong)無機(ji)(ji)固(gu)體(ti)物(wu)(wu)(wu)表面(mian)的有(you)機(ji)(ji)物(wu)(wu)(wu),避免廢(fei)水(shui)中(zhong)有(you)機(ji)(ji)固(gu)體(ti)物(wu)(wu)(wu)在沉(chen)(chen)砂池(chi)(chi)(chi)中(zhong)產生(sheng)沉(chen)(chen)淀(dian),可(ke)(ke)采用曝氣(qi)沉(chen)(chen)砂池(chi)(chi)(chi)。采用初沉(chen)(chen)池(chi)(chi)(chi)可(ke)(ke)降(jiang)低后續工(gong)(gong)藝的負荷。初沉(chen)(chen)池(chi)(chi)(chi)除去懸(xuan)浮固(gu)體(ti)的效(xiao)果與加工(gong)(gong)的原料和(he)產品有(you)關。按(an)池(chi)(chi)(chi)中(zhong)的水(shui)流(liu)方(fang)向(xiang)分為(wei)平流(liu)沉(chen)(chen)淀(dian)池(chi)(chi)(chi)、豎流(liu)沉(chen)(chen)淀(dian)池(chi)(chi)(chi)、輻流(liu)沉(chen)(chen)淀(dian)池(chi)(chi)(chi)。為(wei)了提高沉(chen)(chen)淀(dian)池(chi)(chi)(chi)的沉(chen)(chen)淀(dian)效(xiao)率,可(ke)(ke)在沉(chen)(chen)淀(dian)池(chi)(chi)(chi)內設置平行(xing)的斜(xie)板或斜(xie)管而成斜(xie)板(管)沉(chen)(chen)淀(dian)池(chi)(chi)(chi)。一(yi)般(ban)沉(chen)(chen)淀(dian)時(shi)間(jian)1.5—2.0h。
(5)氣浮
氣(qi)浮(fu)主要用于除(chu)去(qu)食(shi)品工業廢水(shui)中的乳化油、表面活性物(wu)質和(he)其他懸浮(fu)固體。有真空(kong)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(dang)廢水(shui)進(jin)入容(rong)器氣(qi)浮(fu)池之前,往水(shui)中投加化學混凝劑或助(zhu)凝劑,可提高(gao)乳化油脂和(he)膠體懸浮(fu)顆粒(li)的去(qu)除(chu)率。據資(zi)料介紹,氣(qi)浮(fu)可除(chu)去(qu)90%以上的油脂和(he)40%—80%的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(chu)理出水(shui)進行深度處(chu)理,常用(yong)的(de)方法是(shi)過濾(lv)(lv),可采用(yong)砂(sha)濾(lv)(lv)池(chi)或復合濾(lv)(lv)料濾(lv)(lv)池(chi)。按濾(lv)(lv)速大小分慢速砂(sha)濾(lv)(lv)池(chi)和快濾(lv)(lv)池(chi)。一般(ban)單層砂(sha)濾(lv)(lv)池(chi)的(de)濾(lv)(lv)速為8~12m/h。
2.2 化學(xue)處(chu)理法
化(hua)(hua)學(xue)(xue)處(chu)理法是指應用化(hua)(hua)學(xue)(xue)原(yuan)(yuan)理和化(hua)(hua)學(xue)(xue)作用將廢(fei)水(shui)中的污染物成分(fen)轉(zhuan)化(hua)(hua)為無害物質,使廢(fei)水(shui)得到凈化(hua)(hua)。污染物在經過(guo)化(hua)(hua)學(xue)(xue)處(chu)理過(guo)程后(hou)改變了化(hua)(hua)學(xue)(xue)本性,處(chu)理過(guo)程中總是伴隨著化(hua)(hua)學(xue)(xue)變化(hua)(hua)。用于食品工業(ye)廢(fei)水(shui)的化(hua)(hua)學(xue)(xue)處(chu)理法有(you)中和、混凝(ning)、電解、氧化(hua)(hua)還原(yuan)(yuan)、離子交換、膜分(fen)離法等。
(1)混凝法
食品工業廢水(shui)處理中所用(yong)的(de)化學處理工藝主(zhu)要是混(hun)凝(ning)(ning)法(fa)。混(hun)凝(ning)(ning)法(fa)不能單獨使(shi)用(yong),必須與物(wu)理處理工藝的(de)沉(chen)淀、澄清法(fa)或氣浮法(fa)結(jie)合使(shi)用(yong),構成(cheng)混(hun)凝(ning)(ning)沉(chen)淀或混(hun)凝(ning)(ning)氣浮,混(hun)凝(ning)(ning)沉(chen)淀可(ke)作(zuo)為生(sheng)物(wu)處理的(de)預處理,也可(ke)作(zuo)為生(sheng)物(wu)處理后的(de)深度處理。
混凝沉(chen)淀法是(shi)水(shui)處(chu)理的一個重(zhong)要(yao)方法。對于一些膠(jiao)(jiao)(jiao)體顆粒較小、或是(shi)一些膠(jiao)(jiao)(jiao)體溶液,難以或不能發生沉(chen)降(jiang)的廢水(shui)加(jia)入化學混凝劑,使(shi)其形成(cheng)易于沉(chen)降(jiang)的大顆粒而去除(chu)。廢水(shui)中呈(cheng)膠(jiao)(jiao)(jiao)體狀態的蛋白質和多糖類(lei)物質,經(jing)加(jia)藥混凝沉(chen)淀即有較好(hao)的去除(chu)效(xiao)果。
常(chang)用的藥(yao)劑(ji)有(you):石(shi)灰、硫(liu)酸(suan)亞(ya)鐵(tie)(tie)、三氯化鐵(tie)(tie)和硫(liu)酸(suan)鋁等。石(shi)灰一般不(bu)單獨使用,常(chang)與其他藥(yao)劑(ji)配合(he)使用,最佳投藥(yao)量和pH值(zhi)宜通(tong)過試驗確定。
(2)氧化還原(yuan)
化(hua)學氧化(hua)還原是轉(zhuan)(zhuan)化(hua)廢(fei)(fei)水(shui)(shui)(shui)中污(wu)染物(wu)的有(you)效方法。廢(fei)(fei)水(shui)(shui)(shui)中呈溶解狀態的無(wu)機(ji)物(wu)和(he)有(you)機(ji)物(wu),通過化(hua)學反應被氧化(hua)或還原為微毒或無(wu)毒的物(wu)質,或者轉(zhuan)(zhuan)化(hua)成容易與水(shui)(shui)(shui)分離的形(xing)態,從而達到處理的目的
(3)離子交換
離子交(jiao)換主要(yao)是(shi)利(li)用離子交(jiao)換劑對水中存在(zai)的(de)有害離子(包括有機(ji)(ji)的(de)及無(wu)機(ji)(ji)的(de))進行交(jiao)換去(qu)除(chu)的(de)方法。
2.3 生(sheng)物處理(li)法
生(sheng)物化學處(chu)理(li)法(fa)是有機(ji)廢水(shui)處(chu)理(li)系統(tong)中最(zui)重要的(de)(de)過程之一(yi)。在(zai)食品(pin)工(gong)(gong)(gong)業的(de)(de)廢水(shui)處(chu)理(li)中,生(sheng)物處(chu)理(li)工(gong)(gong)(gong)藝(yi)可分為好(hao)氧工(gong)(gong)(gong)藝(yi)、厭氧工(gong)(gong)(gong)藝(yi)、穩(wen)定塘、土(tu)地處(chu)理(li)以及由(you)上述工(gong)(gong)(gong)藝(yi)的(de)(de)結合而形成的(de)(de)各種各樣的(de)(de)組合工(gong)(gong)(gong)藝(yi)。食品(pin)廢水(shui)是有機(ji)廢水(shui),生(sheng)物法(fa)是主要的(de)(de)二級處(chu)理(li)工(gong)(gong)(gong)藝(yi),目的(de)(de)在(zai)于降(jiang)解(jie)COD、BOD5。
好(hao)氧(yang)生(sheng)(sheng)(sheng)物(wu)(wu)處理工(gong)藝根據(ju)所利用的微(wei)生(sheng)(sheng)(sheng)物(wu)(wu)的生(sheng)(sheng)(sheng)長(chang)形式分(fen)為活性(xing)污泥(ni)工(gong)藝和膜法(fa)(fa)(fa)工(gong)藝。前者(zhe)包括(kuo)(kuo)傳統活性(xing)污泥(ni)法(fa)(fa)(fa)、階段曝氣法(fa)(fa)(fa)、生(sheng)(sheng)(sheng)物(wu)(wu)吸附法(fa)(fa)(fa)、完(wan)全混(hun)合(he)法(fa)(fa)(fa)、延時曝氣法(fa)(fa)(fa)、氧(yang)化溝、間歇活性(xing)污泥(ni)法(fa)(fa)(fa)(SBR)等。后者(zhe)包括(kuo)(kuo)生(sheng)(sheng)(sheng)物(wu)(wu)濾(lv)池、塔式生(sheng)(sheng)(sheng)物(wu)(wu)濾(lv)池、生(sheng)(sheng)(sheng)物(wu)(wu)轉盤、活性(xing)生(sheng)(sheng)(sheng)物(wu)(wu)濾(lv)池、生(sheng)(sheng)(sheng)物(wu)(wu)接觸氧(yang)化法(fa)(fa)(fa)、好(hao)氧(yang)流化床等。一(yi)般好(hao)氧(yang)處理對低濃度廢水效果較好(hao)。
厭氧生物處理(li)工藝適用于食品工業廢水,主要原因(yin)是廢水中含易生物降解的(de)高濃度有機物,且無毒性(xing)。此外,厭氧處理(li)動力消耗低,產(chan)生的(de)沼氣可作為能(neng)源,生成的(de)剩(sheng)余污泥量少,厭氧處理(li)系統全(quan)部密閉,利于改善環境衛生,可以季(ji)節性(xing)或間歇性(xing)運轉,污泥可長期(qi)儲(chu)存。