áp dụng hệ số ô nhiễm (bod,cod và ss) và mô hình streepter phelps để tính toán thải lượng ô nhiễm

jw NGHIEN COU '

Ap dung he so 6 nhiem (bod, cod va ss)

va mb hmh streepter - phelps de tmh toan

thai lirang 6 nhiem cua mot so nguon thaj chmh

va kha nang tir lam sach cua nirdc song Cau

(doan chay qua TP Thai Nguyen)

CAl ANH TlJ

Khoa Moi trUdng, Dgi hoc Khoa hgc TU nhien

Sddung he sod nhiem nitdc thdi sinh hogt theo WHO deddnh gid nhanh mdc thdi litctng d

nhiim trong nitdc thdi sinh hogt vd cdng nghiep cda mgt so ngudn thdi chinh tgi TP. Thdi

Nguyen. Md hinh Streepter-Phelps duacsufdung dedi/bdo vekhd ndng tit Idm sgch cda nitdC

sdng Cdu (dogn chdy qua TP. Thdi Nguyen). Ket qud nghien cdu dda ra mdc dp thdi Iddng hien

tgi vd xu hitdng bien doi den ndm 2020 cua mot so nguon thdi chinh* Ben cgnh do, viec sCfdung

md hinh Streepter - Phelps cho thdy, degi&ditcfc nitdc song Cdu dogn chdy qua TP. Thdi Nguyen

dmCtc D0>5mg/lcdn phdi xdly BOD 82,1%. Dieu ndy ddng nghia vdi khd ndng tdtdm sgch ciia

nitdc sdng Cdu la 17,9 %.

dd WHO dl xuat vi md hinh

Streepter - Phelps dupc sfl

dyr^ dl tinh toan khi nai^

tu lim sgch cua nUde sdi^

Cau (dogn chay qua TP. Thii

Nguyin) dupc ap dyng.

g ^ oefficients of domestic

^ I wastewater pollution (by WHO)

\ > are used to assess rapidly the

amount of pollutants discharged in

domestic and industrial wastewater

for some main sources in Thai Nguyen

City. Streepter-Phelps Model is used

to predict the self-cleaning capacity

of Cau river water (Thai Nguyen

City passage). The study results

show current level of waste volume

and the trends to 2020 for some of

main sources. In addition, the use of

Streepter-Phelps Model shows that

that to keep Cau river water (Thai

Nguyen City passage) with DO >5mg/l,

it is necessary to treat 82.1% of BOO.

This means that the self-cleaning

capacity of Cau River water is 17.9%.

I. MO DAU

Chat liictng nifcfc song noi chung, song Cau

noi rieng dang bi 6 nhiem, nhieu doan song

khong dat QCVN 08/2008/BTNMT quy dmh

sil dyng vao cac muc dich cu the dap iing vdi

nhu cau tai dja phuang. Danh gia kha nang txj

lam sach ciia luu v\Ic co vai tro quan trong trong

viec quan ly va BVMT dong song. Vdi muc dich

gop phan bao ve chat luong nudc song, phuang

phap danh gia nhanh thong qua he so o nhiem

II. DOI TUONG VA

PHUONG PHA P

NGHIEN cutr Danh gia nhanh thong

qua he so 6 nhiem nudc thai

sinh hoat theo WHO duac ap

dung la; Vdi miic thai luong 6

nhiem trong nudc thai sinh

hoat chUa qua xil ly trung

binh la:

BODj = 50 g/ngUdi/ngay;

COD = 22 g/ngUdi/ngay; SS =

38 g/ngUdi/ngay.

Tong thai liiong 6 nhi^m

duoc tinh bang tich s6 giiia

dan vi thai lifong 6 nhilm va

so dan.

Mo hinh Streepter - Phelps

de du bao yeu cau ve hi^u qua

xfl ly nudc thai hay kha nang

tvf lam sach cua nudc song, mfi

hinh Streepter - Phelps dU(?c

sfl dung.

D.^ K,xL,

1

At

•10-' -10-' ^D,xW'' ?//)(!)

.1^(2)

Kj = K L X — -

D 2,3x&txD (3)

Trong do:

Dt: Dp suy giam (hay dp thieu hyt) DO d thdi dilm t (mg/I)

Kj: Tdc dp tilu thy DO (ngay-1)

K^: Tdc dp bo sung DO (ngiy-1)

t: Thdi gian tU lue bit dau nhgn thii (dilm khio sit thii 1

den diem khio sat thd 2)

t: Thdi gian di chuyen (tU dilm khao sat thii 1 den dilm

khao sit thU 2 cua ddng sdng (ngiy))

D^: Dp thieu hyt DO d diem khio sit thU 1 (mg/1)

561 Hoi trtidng So 1