The document outlines various methods for determining types of solids in wastewater samples, including total solids, total suspended solids, volatile solids, fixed solids, total dissolved solids, and their significance for classifying wastewater and designing wastewater treatment processes. Gravimetric analysis methods are described for evaporating and igniting samples to separate organic and inorganic fractions. Standards for discharge of treated wastewater are also provided.

1. Sanjivani Rural Education Society’s
Sanjivani College of Engineering, Kopargaon – 423601
(An Autonomous Institute, Affiliated to SPPU, Pune)
ISO 9001:2015 Certified, Approved by AICTE, Accredited by NBA and NAAC (A Grade)
Department of Civil Engineering
Course Title: Environmental Engineering – II (401001)
Solid Determination
Instructor
Mr. Chaudhari V. S (Assistant Professor)
Contact id: chaudharivishalcivil@sanjivani.org.in
Environmental Engineering– II: Solid
Determination

2. Environmental Engineering– II: Solid
Determination
Introduction:-
 Wastewater is normally 99.9 % water and 0.1 % solids. If a wastewater sample is
evaporated at 103 to 1050c , the solids remaining are total solids.
 Solids in waste water indicate the concentrations of organic and inorganic constituents.
The organic fraction defines the pollutional load of waste water and the inorganic
component determines its suitability for irrigation or fish culture.
Total Solids (a)
Total Suspended
Solids (b)
Non-Settleable
Suspended Solids
(d)
Volatile Solids
(Organic)
Non-Settleable (f)
Fixed Solids
(Inorganic)
Non-Settleable (i)
Settleable
Suspended Solids
(c)
Volatile Solids
(Organic)
Settleable (g)
Fixed Solids
(Inorganic)
Settleable (j)
Total Dissolved
Solids (e)
Volatile Solids
(Organic)
Dissolved (h)
Fixed Solids
(Inorganic)
Dissolved (h)

3. Environmental Engineering– II: Solid
Determination
Total Solids (a)
Total Suspended Solids (b)
Volatile Suspended Solids (f+g)
Fixed Suspended Solids (i+j)
Total Dissolved Solids (e)
Volatile Dissolved Solids (h)
Fixed Dissolved Solids (k)
Briefly solids can be classified as:-
When any organic and inorganic components are required.
Total Solids (a)
Total Volatile Solids
(f+g+h)
Total Fixed Solids
(i+j+k)

4. Environmental Engineering– II: Solid
Determination
Importance of solids determination:-
 TS determination (a) classifies waste water as weak (around 350 mg/l),
moderately by (around 700 mg/l) and strong (around 1200 mg/l) waters.
 Settleable SS determination (c) indicates the efficiency of primary
sedimentation. Based on this, whether primary sedimentation is required or not
and if required, detention time to be adopted for PST designs are decided.
 Volatile solids (settleable) (g) indicate the fraction of organic loading of
digesters, contributed by primary sludge from PST.
 Non-settleable suspended solids (d) and non-settleable volatile solids (f)
indicate the pollutional load to be removed by secondary treatment.
 Total dissolved solids (inorganic) (k) indicate the suitability of waste water for
irrigation and fish culture.
 Total volatile solids (f+g+h) determination in sludge’s is used for designing
organic loading of anaerobic digesters and also their efficiency of VS reduction.

5. Environmental Engineering– II: Solid
Determination
Principle of Solid Determination:-
Solids are determined by gravimetric analysis.
 Filtering a known volume of the sample, evaporating the filtrate
to dryness and weighing the residue determine total solids
volatilizing away all the organic matter in a known volume of the
sample and weighing the residue.
Fixed solids are determined by volatilizing away all the organic
matter in a known volume of the sample and weighing the
residue.
 Settle able solids are determined by allowing coarse suspended
solids, with sp.gr >1, to settle under still conditions over a specific
over a specific period of time. The settled sludge is evaporated to
dryness and residue weighed to determine the efficiency of

6. Environmental Engineering– II: Solid
Determination
Discussion
:-
 During total solid & total dissolved solids determine a temperature
of 103oC to 105oC is adopted for evaporating solids to dryness, as
at this temperature only water contents is lost buy no degradation &
loss in weight of solids occur.
Heating solids to 550oC to 600oC during volatile solids
determination result in total degradation & loss of all the organic
content, the organic fraction remains as residue.

7. Environmental Engineering– II: Solid
Determination
STANDARDS RECOMMENDED
Sr.No. Description Maximum Permissible Limit
1.
Sewage effluents discharged into
inland surface waters
TSS , 30 mg/l B.I.S.4764
2.
Industrial effluents discharged into
inland surface waters
TSS , 100 mg/l B.I.S.2490
3.
Industrial effluents falling into marine
coastal areas
TSS , 100 mg/l B.I.S.7968
4.
Inland surface waters to be used on
land for irrigation
TSS , 2100 mg/l (Inorganic) B.I.S.2296

8. Environmental Engineering– II: Solid
Determination
Apparatus Required
Aim: To determine the amount of total, volatile, fixed, suspended & dissolved solids
in the given sewage sample.

9. Environmental Engineering– II: Solid
Determination
Procedure
1. A dry constant weight of empty crucible is taken & weighed accurately on balance Say
(W1)
2. A measured quantity of samples is transferred to the crucible and the contents
evaporated to dryness in hot oven for eight hours at 1030 to 1050c.
sample water

10. Environmental Engineering– II: Solid
Determination
3. It is allowed to cool in desiccators & then weighed accurately. (W2)
After drying in the
oven cool to room
temperature in dessicator
Note down the final dry weight of the
crucible
𝐓𝐨𝐭𝐚𝐥 𝐒𝐨𝐥𝐢𝐝(𝐦𝐠/𝐥) =
𝐖 𝟐 − 𝑾 𝟏 𝒎𝒈 ∗ 𝟏𝟎𝟎𝟎(𝒎𝒍/𝒍)
𝐯𝐨𝐥𝐮𝐦𝐞 𝐨𝐟 𝐬𝐚𝐦𝐩𝐥𝐞 𝐭𝐚𝐤𝐞𝐧(𝐦𝐥)

11. Environmental Engineering– II: Solid
Determination
4. The same crucible is kept in muffle furnace & ignited a 550 ± 500c temperature for 15
minutes.
5. The crucible is taken out from the furnace and allowed to cool in desiccators & weighed
accurately. (W3)
𝐅𝐢𝐱𝐞𝐝 𝐒𝐨𝐥𝐢𝐝(𝐦𝐠/𝐥)
=
𝐖 𝟑 − 𝑾 𝟏 𝒎𝒈 ∗ 𝟏𝟎𝟎𝟎(𝒎𝒍/𝒍)
𝐯𝐨𝐥𝐮𝐦𝐞 𝐨𝐟 𝐬𝐚𝐦𝐩𝐥𝐞 𝐭𝐚𝐤𝐞𝐧(𝐦𝐥)

12. Environmental Engineering– II: BOD
50

13. Environmental Engineering– II: Solid
Determination
6. For determining Dissolved solids, Take another crucible, Let W4 weight of second empty
crucible
Then 50 ml sample is filtered through filter paper & filtrate is collected in crucible say (W4)

14. Environmental Engineering– II: Solid
Determination
7. The filtrate is evaporated to dryness in hot air oven for about eight hour at 1030 to1050c. It
is then allowed to cool in desiccator & weighed accurately (W5)
Dissolved 𝐒𝐨𝐥𝐢𝐝(𝐦𝐠/𝐥) =
𝐖 𝟓
−𝑾 𝟒
𝒎𝒈 ∗𝟏𝟎𝟎𝟎(𝒎𝒍/𝒍)
𝐯𝐨𝐥𝐮𝐦𝐞 𝐨𝐟 𝐬𝐚𝐦𝐩𝐥𝐞 𝐭𝐚𝐤𝐞𝐧(𝐦𝐥)
Suspended solids (Mg/lit.) = Total solids – dissolved solids
Volatile Solids (Mg/lit.) = Total solids – fixed solids

15. Environmental Engineering– II: Solid
Determination
Observation table
Sr.No Sample
No.
W1 W2 W3 W4 W5 Solids contents Mg/lit.
Total Fixed Volatile Dissolved Suspended
1
SAMPLE
No. 1

16. Environmental Engineering– II: Solid
Determination