Never: Sewage Treatment and Biochemical Oxygen Demand Essay

Submitted By yinzhichao
Words: 796
Pages: 4

ENVIRONMENTAL ENGINEERING

CEG8101-CORE CONCEPTS IN ENVIRONMENTAL ENGINEERING
COURSECORK 1, PART A DISCHARGE COMPLIANCE FOR A SYNTHETIC WASTEWATER SAMPLE

NAME: ZHENG YAO
STUDENT NUMBER: 130501851
MODULE LEADER:
DATE OF SUBMISSION:

1.0 Introduction
Urban wastewater can be defined as the mixture of domestic wastewater from baths and toilets, waste water from industries discharging to sewers and rainwater run-off from roads and other impermeable surface. Currently, the impact of discharging urban wastewater cause strongly concern in most countries. An effective sewage treatment system will be significant to human health and the protection of environment (Muchuweti et al., 2004).

1.1 Aim
This investigation aims to determine whether the synthetic wastewater sample has made a request to the Environment agency for permission to discharge directly into the nearest river.
1.2 Objectives
The objectives of this investigation were to analyze the three samples: Raw Sewage, Settled Sewage and Final Effluent. There is some key effluent parameters should be calculated as follow: Dissolved Oxygen (DO): Biochemical Oxygen Demand (BOD) and Chemical Oxygen Demand (COD) Solids: Including Suspended Solids (SS) and Volatile Suspended Solids (VSS) Nitrogen Determination: Total Kjeldahl Nitrogen (TKN), Ammoniacal Nitrogen (NH3-N) and Organic Nitrogen (Org-N)
The result should be compared with wastewater treatment process. In order to decide whether the sample effluent can be discharged from company, the parameters of final effluent should be assessed and compared with the EU Urban Wastewater Directive (91/271/EEC). 2.1 Dissolved Oxygen - BOD and COD The DO was tested by the DO meter/ probe The Biochemical Oxygen Demand (BOD) was determined by using 5-Day BOD Test (5210 B), Preparing dilution water by adding 1 ml prepared solutions. Then dilute sample into three different concentrations and determine initial dissolved oxygen on fourth bottle. Incubate BOD bottles full of dilution water and blank bottle for 5d at 20℃ then measure the dissolved oxygen after incubation period. The Chemical Oxygen Demand (COD) was tested by Closed Reflux, Titrimetric Method (5220 C), place sample in culture tube; add Potassium dichromate to oxidase the reducing substance. Using ferroin as indicator. Then add ammonium ferrous sulfate, preheat to 150℃ and reflux for 2 h. 2.2 Concentration of Nitrogen Total Kjeldahl Nitrogen, TKN was tested by using Semi-Micro-Kjeldahl Method (4500-Norg C), Ammoniacal Nitrogen (NH3-N) was determined by using Titrimetric Method (4500-NH3 E), 2.3 Solids Suspended Solids were obtained from the Total Suspended Solids Dried at 103-105℃ Method (2540 D), Volatile Suspended Solids were determined via the Fixed and Volatile Solids Ignited at 500℃ Method (2540 E),

3.0 Results
Parameter
Unit
Company’s sewage
Required
Directive
(91/271/EEC)
Compliance
Check
BOD mg/L 219.9
25
Failed
COD
mg/L
348
125
Failed
Total suspended solids (ss) mg/L 45.9
35 mg/l
35 (more than 10000 p.e.)

60 (2000-10000 p.e.)
Failed
Total Nitrogen mg/L 30.8
15 mg/l N
(10.000-1000.000 p.e.)
10 mg/l N
(more than 1000.000 p.e.)
Failed
VSS mg/L 44.1
N/A
N/A
VSS
%VSS in SS
96.1
N/A
N/A

Appendices
Appendix 1: Biochemical Oxygen Demand (BOD)
The value of BOD can be calculated by the following formula
BOD5 (mg/L) = ( D1 – D2 ) – ( B1 – B2 )f P
Sewage sample for dilution 1/200
D0 = 8.27 mg/l, the averaged D5 = 6.21 mg/l.
B0 = 8.29 mg/l, the averaged B5 = 8.43 mg/l
BOD5 (mg/L) = ( 8.27 – 6.21 ) – ( 8.29 – 8.43 )99/100 1/100 =219.9 mg/l BOD5
Appendix 2: Chemical Oxygen Demand (COD)
Calculation method: mg/l D.V. = ( a - b ) c x 8000 ml sample…