This document discusses the treatment of waste water from the cashew nut processing industry in India. It provides background on the industry and production levels in India. It then describes the sources and characteristics of the wastewater, which contains toxic cashew nut shell liquid (CNSL) that is difficult to treat using conventional biological methods. The document reviews various treatment alternatives that have been studied including aerobic reactors with fungal inoculums, bioaugmentation with specific microorganisms, and enzymatic bioremediation approaches. It concludes that biological remediation technologies show promise for treating this type of wastewater but further optimization is needed given the recalcitrant nature of some CNSL components.

1. TREATMENT OF WASTE WASTER
FROM CASHEW NUT PROCESSING
INDUSTRY
VISHNU RAJ R
14CE63R09

2. INTRODUCTION
 India is a leading producer ,processor & exporter of
cashew in the world with annual production of
6,20,000 MT.
 Cashew nut industries are mostly located in
peninsular india .
 Listed as "Orange" Category Industries by various
SPCBs.
 There are two commonly followed methods of
cashew nut processing
Roasting process & Cooking process

3. PROCESS FLOW
DIAGRAM

4. INDIAN SCENARIO
 Roasting process is more popular in India, mostly in
Kerala.
 The roasting of cashew seeds is carried out in an
inclined rotating open drum. Due to the high
temperature of the drum, the CNSL in the cashew nut
catches fire spontaneously and the nuts are roasted
 The cashew nuts, in burning state, are discharged at the
outlet of the drum and quenched immediately with spray
of water to prevent further roasting.
 These are small and medium scale industries ,man
power intensive and with majority having no pollution
abatement systems.

5. SOURCES OF WASTE WATER GENERATION
 Initial washing of the raw cashew nuts.
 Water used in the humidification step
 Washing of flue gases from boiler
 Washing of the equipment and the floor
CHARACTERSTICS OF EFFLUENT
 The main liquid waste from the cashew nut processing are
contaminated with CNSL (Cashew Nut Shell Liquid)
 CNSL is a caustic, viscous liquid, which contains phenolics,
mainly cardanol (60–65%).
 CNSL is a liquid immiscible in water, because their
components are highly hydrophobic
 These phenolic compounds of high persistence, have acid
characteristics, potentially carcinogenic and mutagenic

6.  Despite being a by-product collected for marketing,
significant amount of CNSL is lost in the effluent. This is
due to the fact that extraction process is not yet fully
efficient.
 The effluent generated has its color & varies from dark
brown and black.
 Treatment is often difficult by conventional means, as
these compounds inhibit normal microbial populations of
functions, therefore, affecting the biological treatment
process (Rajkumar & Palanivelu, 2004).

7. COMPOSITION OF CNSL
CNSL is used for the production of paints, varnishes
,dyes, lubricants, disinfectants, insecticides.

8. EFFECTS ON WATER BODIES
 Concentration above 1 mg/L can affect aquatic life.
 The acute hazard to fish, aquatic invertebrates, and
aquatic plants is based on estimated toxicity values
for cardanol of 0.001 mg/L, 0.004 mg/L, and 0.010
mg/L, respectively.
 Alkylphenols like cardanol have low solubility and
can contaminate the sediments of rivers (Unger &
Newman ,2003)
Source: U.S. EPA December, 2009 Hazard Characterization Document

9. WASTEWATER DISCHARGE
CHARACTERIZATION
Parameter mg/l
 TSS - 1175 –2115
 TDS - 2240 –4284
 O&G - 1400 –2068
 BOD - 5200 –10,424
 COD - 14,790 –27,600
 pH - 7.2-8.2
Source:CPCB

10. ECOTOXICOLOGICAL ANALYSIS OF CASHEW
NUT INDUSTRY EFFLUENTS
 This study assessed the toxicity of this industrial
effluent, specifically two of its major components, cardol
and cardanol, using the brine shrimp (Artemia sp.)
lethality assay
 Survivors were counted after 24 and 48 hr of incubation
of nauplii with samples.
 The LC50 of cardol was 0.56 and 0.41 mg/L after 24 and
48 hr exposures, respectively, and of cardanol was 1.59
and 0.42 mg/L
 Data from this study suggested that the cashew nut
industry effluents are highly toxic to the environment in
the Artemia sp. model and are potentially harmful to the
environment
Martins et al , Pan-American Journal of Aquatic Sciences (2009),

11. WASTE WATER DISCHARGE STANDARDS
Parameter mg/l
 BOD (270C and 3 days) - 30
 Oil & Grease - 10
 Suspended Solids - 100
 Phenol - 1.0
 pH - 6.5-8.5
Source :CPCB

12. EFFLUENT TREATMENT
 Wastewater will be collected in a terminal collection
cum buffer tank.
 Being a reclamation project, the entire wastewater
has to be collected in a central place and treated to
meet the good quality BOD norm of < 20 mg/l.
 SBR (Sequential Batch Reactor) system is normally
recommended which will consist of:
 Collection-cum-aeration-cum-settling tank
 Sand Bed Filter system for decanted water filtration
 Sludge drying bed for excess sludge
CPCB industrial document

14. AEROBIC REACTOR WITH FUNGAL
INOCULUMS (MARCUS ET AL)
 Studies were conducted to assess the feasibility of an aerobic
reactor inoculated with the fungus Aspergillus niger in
reducing the toxicity of the effluent from the cashew
processing industry
 The study was on the effluent from WWTP of an industry that
offers a treatment which basically consists of five steps:
separation of coarse solids; equalization with aeration;
screening; decantation and addition of hydrogen peroxide
(aqueous 15 to 20% concentration) .
 Reactor in this study used an aerobic fixed bed reactor and
upward continuous flow inoculated with the fungus Aspergillus
niger found in the waterbodies receiving effluent from indutry.
 Once the nutrient solution started to be fed to the reactor the
process of developing fungi were accelerated.

15.  The analysis results show a significant positive
correlation between both toxicity and phenolic content
(correlation coefficient = 0.53), and between toxicity and
COD (correlation coefficient = 0.60)
 Fungal fixed bed reactor and upflow operated with a
hydraulic retention time of 12 hours was highly efficient
in reducing toxicity, total phenols and COD of effluent
studied.
 Filamentous fungi inoculated was dominant initially but
at the end of the experiment yeast were capable of
degrading the effluent satisfactorily.
 The fact that yeast manage to survive in such a hostile
effluent environment, degrading it and dominating all the
space at the expense of filamentous fungi, highlights the
great adaptive capacity of these organisms.

16. ENZYMATIC BIOREMEDIATION OF CNSL
CONTAMINATION(SOLY ET AL)
 The aim was to find the utility of enzymes,
oxidoreductases and proteases for the
bioremediation of CNSL
 The results show that peroxidase reduced the color
of the CNSL solution by polymerization and
precipitation.
 Laccase, papain and fungal and bacterial protease
degraded the phenolic constituents.
 The degradation was mainly at the double bonds of
the C15 hydrocarbon chain of the cardanol

17. BIOAUGMENTATION OF WASTEWATER FROM CASHEW
INDUSTRY (JERONIMO ET AL. 2012)
 The study was aimed to assess the technical feasibility of the
application of specific commercial strains of microorganisms
(bioaugmentation) in the treatment of effluent coming from the
processing of cashew nuts
 The effluents collected were from the washing processes and
humidification of cashew nuts.
 Treatment tests were conducted with the addition of additive
dose(about 25 mg / L).
 The additive comprised of enzymes and viable bacteria (e.g.
Pseudomonas aeruginosa LP602, Acinetobacter calcoaceticus)
 Effectiveness of COD removal was measured on different
operating conditions-anaerobic process ,aerobic process (without
agitation) and the aerobic process with mechanical agitation.
 The performance was monitored at the above three conditions
,observing change in pH, Acidity , COD, conductivity and turbidity
over time.
 It was concluded that the application of aerobic technique with
agitation proved to be more viable with removal COD of the
medium at levels greater than 80%.

18. TREATMENT ALTERNATIVES
 The fungi used in biological reactors appear to be an
alternative for the treatment of industrial effluents.
 The potential of these microorganisms to degrade different
types of substrates due to secretion of different enzymes,
which act on the organic pollutant , making it more accessible
to biodegradation (Rodrigues et al, 2006) .
 In addition, the rapid reproduction and proliferation of these
microorganisms and the ability to withstand possible
variations of organic matter, oxygen, moisture and pH can be
mentioned as indicators of viability employ them in biological
reactors for the wastewater treatment (Rodrigues et al., 2006).
 Such microorganisms in general, they promote degradation of
aromatic compounds, through enzymatic systems P450
monooxygenase and lignolítico (Prenafeta boldu 2002).

19. CONCLUSION
 Cashew nut industry waste water is rich in phenolic
contents.
 Conventional biological treatments to these
effluents are not satisfactory as they contain high
amount of not easily biodegradable contents.
 Bio remediation technologies can be used for
treatment of these type of waste water.
 Reactors using Fungi is another alternative for
treatment.

20. REFERENCES
 Cashew nut processing: Sources of environmental pollution and standards-Atul mohod,
Sudhir jain and Powar A.G.
 Bioaugmentation of wastewater from cashew industry- C. E. M. Jerônimo, H. G.
Fernandes , H. N. S. Meloe, J. F. Sousa
 Removal of macronutrients from effluent of a cashew nut industry by using a batch
aerobic reactor with fungal inoculums- Marina Santos da Silva Lopes; Patrícia Celestino
Carvalho de Oliveira; Marcus Vinícius Freire Andrade
 Comprehensive Industry Document – Cashew Seed Processing Industries,CPCB
 Ecotoxicological analysis of wastewater of cashew chestnut processing industry before
and after treatment in aerobic reactor inoculated with fungi.- Marcionília Fernandes
Pimentel ,2010
 Technical study for alternative treatment of oily wastewater arising from the cashew nut
industries- jerônimo, carlos enrique de medeiros
 Organic matter removal efficiency of phenolic wastewater of cashew processing
industry by batch reactor with use of Aspergillus niger AN 400-Carla Bastos VIDAL
 Degradation of Cashew Nut Shell Liquid by Pseudomonas sp Isolated from Soil- T.
Rajeswari, B. Padmapriya
 Isolation, Identification and Methanogenesis of CNSL Degrading Bacteria and
Immobilized Bioremediation Techniques of CNSL and its Contaminated Water from
Cashew Industry- S. Sabna Prabha,
 Enzymatic bioremediation of cashew nut shell liquid contamination-Soly Cheriyan,
Emilia T. Abraham