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Tannery Effluent Treatment

Despite all preventive measures, a sizeable portion of pollutants can only be removed by the end-of-pipe methods, i.e. treating effluents discharged in the course of leather processing. One of the most successful areas of interventions implemented or facilitated by UNIDO was designing and managing the construction of cost effective [Common] Effluent Treatment Plants ([C]ETP). More than 250 such plants have been designed, established or upgraded through various technical assistance projects. Achievements and experiences were documented in technical papers, reports and manuals which are available in this section. A special Animated Visual Training Tool was also developed by UNIDO and is available in the section “e-Learning".

Recommendations and preventive measures in response to COVID-19: Guidance for the industrial sector

This tool provides guidance to employers, workers and their representatives on preventive measures for a safe return to work in the context of COVID-19, conforming to well established principles and methods on occupational safety and health risk management.

There are many other useful guidelines and recommendations available.

"SAFE Leather" must mean safe for operators and workers, as well as safe for consumers and communities. Company management must ensure that the workplace provides workers and anyone else attending the workplace with access to appropriate first aid equipment. Management must also ensure that the workers have access to an adequate number of persons who have been trained to administer first aid.

First Aid course/training should be mandatory for all emplyees. 

First Aid course Modules
Module 1: First Aid Kit - content
Module 2: First Aid Dealing with Heart Attack
Module 3: First Aid Dealing with Burns
Module 4: First Aid Dealing with Accidents Involving Chemicals
Module 5: First Aid Dealing with Contusions
Module 6: First Aid Dealing with Eye Injuries
Module 7: First Aid Dealing with Severe Bleeding
Module 8: First Aid Dealing with Eelectricity

 

To enroll into the course please follow the linkhttps://learning.unido.org/course/view.php?id=19

UNIDO Course Introduction to treatment of tannery effluents

The course, “Introduction to Treatment of Tannery Effluent” is designed for training institutions, private companies, and individuals that require an understanding of effluent treatment methods in the leather industry. The course is recommended to be used in a blended approach via classroom instruction using training content or self-learning along with an allocation of time for hands-on application in the laboratory.   There are 5 modules in this course as below:

Module 1: Load, norms, in-house treatment. This module will explain the aim of effluent treatment; pollution load and the main wastewater quality parameters; typical discharge norms.  It will also offer a general overview of the treatment of tannery effluents, segregation of streams, treatment of spent liming floats, and treatment of chrome-bearing floats
Module 2: Treatment within tannery compound. This refers to the pre-treatment for discharge into the common effluent treatment plant (CETP) collection network, and physical-mechanical (primary) treatment for discharge into municipal sewage.
Module 3: Sludge dewatering.  This module explores sludge thickeners, sludge pumps, filter press, centrifuge, belt filter press, flow-chart of physical-chemical treatment, and sludge drying beds.
Module 4: Biological (secondary) treatment.  This module looks into activated sludge, aeration devices, oxidation ditch, and the flow-chart of the biological treatment
Module 5: Occupational safety and health (OSH) in CETP, and its costing and management

Link to the course: https://learning.unido.org/course/view.php?id=6

Tanning industry is an important segment of UNIDO technical assistance in promoting sustainable development. In late 90-ies a number of studies dealing with various cleaner tanning methods, including the widely used paper The Scope for decreasing pollution load in leather processing, were prepared to support different forms of training activities (shop-floor demonstrations, pilot plants, national and regional workshops etc).

In the meantime a lot of practical experience has been gathered, some new tanning technologies developed and implemented and some new challenges have also emerged.  Since proper training is essential precondition for modern, sustainable leather processing, it is felt that a single, comprehensive paper on cleaner leather technologies, rounding up and updating earlier papers, could be of great help in training and capacity building activities.

In addition to traditional cleaner technologies topics such as pollution sources/loads, water management, hair-save liming, low- or ammonia-free deliming, chrome management, low-organic solvents finishing, solid waste management etc., this comprehensive study addresses virtually all issues relevant for performance and successful tanning operations: tannery environmental management systems (EMS/CSR), Restricted Substances Lists (RSL), energy considerations, mechanical operations, Occupational Safety and Health at workplace (OSH), Carbon Footprint (CF) and Life Cycle Analysis (LCA) which are so often the subject of extensive debates in various international fora and media.

The study also includes many tables, charts and (equipment) photos accompanying and illustrating the text.

It is envisaged that the document will serve as a basis for developing globally accessible eLearning courses on sustainable leather manufacture.

There are also other useful information and sources e.g. Tannery of the Future. The Tannery of the Future tool gives tanners an initial indication of the areas in which they need to become more sustainable, e.g. housekeeping, waste management, working conditions and wages. It also provides references to sources of more in-depth information and guidance.

The Leather Working Group (LWG) has launched an online training platform designed to educate leather manufacturers and other members of the leather supply chain on responsible operating practices.

Ажлын байранд гарч болох аюул, эрсдлүүдийг таниулах, осол гэмтлийн үед эмнэлгийн тусламж ирэхээс өмнө цаг алдалгүй, өөртөө болон бусдад анхны тусламжийг аюулгүй, зөв үзүүлэх мэдлэг, чадварыг олгох зорилготой “Ажлын байранд анхны тусламж үзүүлэх нь” цахим хичээл Монгол хэлнээ нээгдлээ.

Сургалтын материалд бодит жишээг гутал, арьс шир боловсруулах үйлдвэрийн орчинд авч үзсэн байгаа ч аливаа осол гэмтлийн үед анхны тусламж үзүүлэх арга нь ижил тул сургалтын материалыг ноос, ноолуур, уул уурхай, барилга зэрэг дурын салбарт ашиглах боломжтой. Салбарын онцлогоос хамаарч 8 модулиас хэрэгцээ шаардлагын дагуу сонгон хэрэгжүүлж болох юм. Цахим хичээлийг сонирхсон хүмүүс Интернэтэд холбогдсон суурин болон зөөврийн компьютер, таблет, ухаалаг утас ашиглан хүссэн цагтаа хаанаас ч үзэж судлах боломжтой

 

Нэмэлт мэдээлэл

 Цахимаар суралцах талбар 

https://learning.unido.org/course/view.php?id=40   (copy and paste this link into browser)

Цахим курст бүртгүүлэх заавар ба төслийн танилцуулга https://drive.google.com/drive/folders/1gClR2hm_UNXcpZLNmxzEfsnGGNhrnQ9w

The precarious situation with water and soil pollution in the area of tannery clusters along the Palar River prompted the state environmental authorities to press for adherence to TDS discharge limits as well as to impose an approach not practiced in the tanning industry: a Zero Liquid Discharge (ZLD) concept.

Essentially, the ZLD systems concentrate dissolved solids by Reverse Osmosis (RO) and some kind of Multi Effect Evaporation (MEE) until only damp solid waste remains. Solid waste is disposed and nearly all water is reclaimed and reused. Accordingly, some of the existing Common Effluent Treatment Plants (CETPs) have been supplemented by RO and MEE, together with auxiliary steps (tertiary treatment, water softening etc.).

The analysis investigates and relates raw and equalized effluent inflows, RO feed, permeate and reject, evaporator feed and condensate and the yield of recovered, reusable water. Since the energy costs are critical for the viability of the entire concept, data about energy consumption (thermal, electrical main and Diesel) at key stages (RO, multistage evaporation) are consolidated, analysed and correlated. Additional energy needs and costs are compared with those for conventional (CETP) treatment and estimates made of the carbon footprint increase caused by the ZLD operations.

 

Hydrogen supplied gas present in tanneries and effluent treatment plants (ETPs) has proven fatal to workers exposed to it many times.

It is therefore necessary that the owners and managers of tanneries and effluent treatment plants are fully aware of the dangers posed by this poisonous gas and take all preventive and precautionary measures to protect the workforce from exposure to this gas. In the event of accidental exposure of a worker, they should know how to deal with the situation.

UNIDO’s activities in the leather processing has as one of its important objectives, improvement of occupational safety and health practices in tanneries and effluent treatment plants. Under this objective, the project has been seeking to demonstrate in selected tanneries improvement practices for better occupational health and safety of the workers.

It is hoped that the industry representatives and other concerned with the occupational health and safety of workers in tanneries and effluent treatment plants will find this publication useful.

UNIDO on-line learning How to deal with hydrogen sulphide gas

Confronted with increasing legal and social pressures, no tanner can afford the luxury of not being familiar with the main issues and principles of occupational, safety and health protection pertaining to tannery operations.

Hydrogen sulphide gas present in tanneries and effluent treatment plants has proven fatal to workers exposed to it many times.

See also Safety Video - How to deal with hydrogen sulhide gas

It is therefore necessary that the owners and managers of tanneries and effluent treatment plants are fully aware of the dangers posed by this poisonous gas and take all preventive and precautionary measures to protect the workforce from exposure to this gas. In the event of accidental exposure of a worker, they should know how to deal with the situation.

The lessons that follow are to help tanners, tannery managers and operators to acquaint themselves with the basic principles How to deal with hydrogen sulphide gas.

The on-line course developed by UNIDO including test provides an opportunity for the proper training within tanneries related to danger associated with hydrogen sulphide gas. After finishing the test with minimum score 80%, participants will receive the certificate and will be able to download it.

How to enrol into the UNIDO on-line course “ How to deal with hydrogen sulphide gas”?

Follow a link: https://learning.unido.org/course/view.php?id=42 

Enrolment key: H2Safety

 

It is hoped that the certificate will be accepted also by Occupational Safety and Health Authorities as a proof that staff was properly trained.

In view of ever increasing legal and social pressures, no tanner can afford to be unfamiliar with the main issues and principles of environmental protection pertaining to tannery operations. Among these, preventing pollution and promoting cleaner leather processing, which ultimately leads to lower treatment costs, clearly remain a priority. Through the application of industrially proven low-waste advanced methods - such as using salt-free preserved raw hides and skins, hair-save liming, low-ammonia or ammonia-free deliming and bating, advanced chrome management system, etcetera - it is possible to decrease the pollution load expressed as COD and BOD5 by more than 30%, sulphides by about 60 to 70 %, ammonia nitrogen by 80%, total (Kjeldahl) nitrogen by 50%, chlorides by 70%, sulphates by 65 % and chromium by 90%. Yet, despite all preventive measures, there is still a considerable amount of pollution load to be dealt with by the end-of-pipe methods. The purpose of this booklet is to help a tanner or a tannery manager (possibly a well-trained leather technologist) to get familiarized with basic principles and methods of treatment of tannery effluents. This knowledge should make him better equipped for communications with the factory’s environmental unit, environmental authorities and NGOs. To keep the manual short and concise, there are many simplifications and omissions of details; for in-depth understanding of the complexities of treatment of effluents and solid wastes (sludge) we recommend you to consult extensive literature on this subject. Finally, and contrary to the widespread misperception that vegetable tanning is environmentally harmless (in reality its effluents have very high, difficult-to-treat COD), the manual basically refers to the combined chrome tanning (i.e. chrome tanning supplemented by vegetable and synthetic tanning agents) because it is by far the most prevailing leather tanning method.

In Chennai and Tamil Nadu/India, which was the basis for demonstration of UNIDO regional projects, circumstances at the time of project (mid 90's) commencement were such that the tanning Industry was under considerable pressure vis-à-vis effluent treatment. As a result several tanneries or clusters had already undertaken investments in primary or secondary effluent treatment. Rather than create a possible redundant model plant, the project strategy was oriented towards demonstration of four full scale model effluent treatment plants representing different aspects of tannery effluent treatment plant in terms of influent, treatment process and size. Thus, the Ranitec CETP with treatment capacity of 4,000 m3/d receiving effluent from 76 tanneries processing from raw to finished and using amongst others an anaerobic treatment system (lagoon) was upgraded to serve as a model for similar treatment plants in the region. The Vishtec CETP with a capacity of 3,400 m3/d of effluent using two stage aerobic treatment system was upgraded (mainly process control) to be a second model site. The President Kid Leather Company ETP, 120 m3/d receiving effluent from semi-finished to finished tanning processes from an isolated was upgraded as a model site (automatic dosing, laboratory). The MHT Company ETP, capacity 100 m3/d, receiving effluent from a traditional isolated vegetable tannery, a low cost anaerobic treatment system, was upgraded and serves as a model for similar units.

Detailed reports describing assisted tannery effluent treatment plants:

i) Common Effluent Treatment Plant, Amburtec, Ambur, India

ii) Common Effluent Treatment Plant, Kolkota, Leather Complex Kolkota, India

iii) Effluent Treatment Plant,  Meera Hussain Tannery, Melvsiharam, India

iv) Common Effluent Treatment Plant, Pallavaram, Chennai, India

v) Common Effluent Treatment Plant, Ranitec, Ranipet, India

vi) Common Effluent Treatment Plant, SIDCO, Ranipet, India

vii) Common Effluent Treatment Plant, VISHTEC, Melvisharam, India

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