Surface water analysis

Surface water analysis

1. Surface water?

Surface water is the surface water of the earth such as rivers, lakes, swamps, or oceans. Surface water is lost due to evaporation, penetrates into the ground where it becomes groundwater, used by trees in the process of evaporation, used by humans for agriculture, living, industry … or flows into the sea where it becomes salt water.

2. Features of Surface water analysis

• Regular domestic existence of dissolved gas
• Surface water has a large concentration of suspended substances especially in the flow. The suspension is very different, starting from the colloidal particles to the tangible elements that follow the rivers as the flow increases significantly.
• In surface water, there are organic substances of natural origin due to the decomposition of organic matter plants and live animals on the surface of water tanks or in rivers and microorganisms that self-decompose after death. (plants and animals)
• Survival of floating organisms in surface water: Surface water is an important place of residence and development of floating plants (algae) and floating animals. Under certain conditions underwater life can be thrived: Including the development of plants, animals, fish
• Daily changes (temperature difference, sunlight) vary with season, climate change (temperature, ..) and of plants (deciduous). They can happen randomly like rain, thunderstorms, strong pollution. In surface water storage areas, water quality changes from surface to bottom of the reservoir (O2, Fe, Mn, oxidation ability, floating organisms). The content of each element varies depending on the cycle of a year

3. Why need to analyze surface water quality

Water testing is the work to do to find water source problems. As a basis for controlling waste sources into receiving sources, ensuring surface water sources are always suitable for use purposes and at the same time to implement measures to improve and restore water quality and protect and use water appropriately.

4. Indicators in surface water need testing

The criteria in surface water include 36 targets according to the National Standard QCVN 08-MT: 2015 / BTNMT on surface water quality.

Limited value of quality parameters for surface water analysis

STT	Thông số	Đơn vị	Giá trị giới hạn
			A		B
			A1	A2	B1	B2
1	pH		6-8,5	6-8,5	5,5-9	5,5-9
2	BOD5 (20°C)	mg/l	4	6	15	25
3	COD	mg/l	10	15	30	50
4	Ôxy hòa tan (DO)	mg/l	≥ 6	≥ 5	≥ 4	≥ 2
5	Tổng chất rắn lơ lửng (TSS)	mg/l	20	30	50	100
6	Amoni (NH4+ tính theo N)	mg/l	0,3	0,3	0,9	0,9
7	Clorua (Cl–)	mg/l	250	350	350	–
8	Florua (F–)	mg/l	1	1,5	1,5	2
9	Nitrit (NO–2 tính theo N)	mg/l	0,05	0,05	0,05	0,05
10	Nitrat (NO–3 tính theo N)	mg/l	2	5	10	15
11	Phosphat (PO43- tính theo P)	mg/l	0,1	0,2	0,3	0,5
12	Xyanua (CN–)	mg/l	0,05	0,05	0,05	0,05
13	Asen (As)	mg/l	0,01	0,02	0,05	0,1
14	Cadimi (Cd)	mg/l	0,005	0,005	0,01	0,01
15	Chì (Pb)	mg/l	0,02	0,02	0,05	0,05
16	Crom VI (Cr6+)	mg/l	0,01	0,02	0,04	0,05
17	Tổng Crom	mg/l	0,05	0,1	0,5	1
18	Đồng (Cu)	mg/l	0,1	0,2	0,5	1
19	Kẽm (Zn)	mg/l	0,5	1,0	1,5	2
20	Niken (Ni)	mg/l	0,1	0,1	0,1	0,1
21	Mangan (Mn)	mg/l	0,1	0,2	0,5	1
22	Thủy ngân (Hg)	mg/l	0,001	0,001	0,001	0,002
23	Sắt (Fe)	mg/l	0,5	1	1,5	2
24	Chất hoạt động bề mặt	mg/l	0,1	0,2	0,4	0,5
25	Aldrin	µg/l	0,1	0,1	0,1	0,1
26	Benzene hexachloride (BHC)	µg/l	0,02	0,02	0,02	0,02
27	Dieldrin	µg/l	0,1	0,1	0,1	0,1
28	Tổng Dichloro diphenyl trichloroethane (DDTS)	µg/l	1,0	1,0	1,0	1,0
29	Heptachlor & Heptachlorepoxide	µg/l	0,2	0,2	0,2	0,2
30	Tổng Phenol	mg/l	0,005	0,005	0,01	0,02
31	Tổng dầu, mỡ (oils & grease)	mg/l	0,3	0,5	1	1
32	Tổng các bon hữu cơ (Total Organic Carbon, TOC)	mg/l	4	–	–	–
33	Tổng hoạt độ phóng xạ α	Bq/I	0,1	0,1	0,1	0,1
34	Tổng hoạt độ phóng xạ β	Bq/I	1,0	1,0	1,0	1,0
35	Coliform	MPN hoặc CFU /100 ml	2500	5000	7500	10000
36	E.coli	MPN hoặc CFU /100 ml	20	50	100	200

Note:

The classification of A1, A2, B1 and B2 for surface water sources to assess and control water quality, serving different purposes of water use, are arranged according to the level of descending quality..

A1- Used for domestic water supply (after normal treatment), conservation of aquatic plants and animals and other purposes such as types A2, B1 and B2.

A2 – For drinking water purposes, it must apply appropriate treatment technology or purposes such as types B1 and B2.

B1- For irrigation, irrigation or other uses requiring similar water quality or purposes such as B2.

B2 – Water transport and other purposes with low quality water requirements.