Abstract

The name of this degree work is “ecological bases of wastewater leather industry”. In work it is considered types of treatment sewage water in leather industry, production technology, types of waste and methods of their cleaning. The new technology of processing of the waste of tanning, by by calcium hydroxide and sodium hydroxide combination from chromium ions(vi). Chromium is a common pollutant introduced into natural waters due to the discharge of a variety of industrial wastewaters. On the other hand, chromium based catalysts are also usually employed in various chemical processes, including selective oxidation of hydrocarbons. In all over the world, chromium (cr) is dominant in most of the effluent streams as compared to other heavy metal ions[2]. Caio f etal found that a reduction of more than 1.0 x 10⁵ and 4.0 x 10⁵ fold in total chromium and hexavalent chromium concentrations, respectively, was observed by employing steel wool masses as low as 0.4420 g to 30 ml solutions of wastewater [3].the optimum ph for the precipitating chromium from tannery wastewater is 7.7-8.2 with a lime concentration (2g/100ml) and the effective settling rate was 120min. The bioremoval of cr (vi) using actinomycetes is a suitable mean for reducing the tannery wastewater toxicity. The combination between the chemical precipitation and the biological removal of chromium from tanning wastewater make it meet the environment safely

Content

	Standard references…………………………………………………….	5
	Definition………………………………………………………………	6
	Abbreviations………………………………………………….............	7
	Introduction…………………………………………………………….	8
1	Leather industry………………………………………………………..	11
2. 2.1	Chromium in leather industry ………………………....................... Environmental considerations…………………………......................	17 17
3.	Chromium salts………………………………………………..............	22
3.1	Chemistry of chromium………………………………………………..	22
3.2	Trivalent chromium (cr3+)……………………………………………...	23
4.	Environmental protection and life safety……………………………...	55
5.	Economic damage...………………………………………………….	64
6	The calculation of the wastewater ……………………………………..	68
	Conclusion……………………………………………………………...	82
	References………………………………………………………...........	83

Standard references

Environmental code of the republic of Kazakhstan

Water code of the republic of Kazakhstan

Forest code of the republic of Kazakhstan

State water cadastre

Emission standards determination

Natural resource status standards: subsoil and subsoil use, on wildlife protection, reproduction and use, as well as land, water and forest laws of the republic of Kazakhstan.

Expert council for technical regulation

Introduction of international standards

Environmental labeling

Expert council for technical regulation

Introduction of international standards

Definition

“Environment” means all natural and artificial objects, including air, ozone layer of the earth, surface water and groundwater, land, subsoil, flora and fauna, the climate, and the interaction there between;

“Environmental damage” means environmental pollution or extraction of natural resources in excess of the established limits, which causes or may cause degradation and depletion of natural resources or death of living organisms;

“Emission” means discharge or release of pollutants, industrial and consumption waste placement into the environment, and also harmful physical effects;

“Environmental protection” means a system of governmental and social efforts to preserve and restore the environment; to prevent adverse impact, and to mitigate consequences, of economic and other activities on the environment;

“Environmental pollution” means the presence in the environment of any pollutants, radioactive materials, industrial and consumption waste, and also the effects of noise, vibration, magnetic fields and other harmful physical effects on the environment;

“Polluted areas” means confined areas of land surface or water bodies, which have been polluted with hazardous chemical agents in excess of the prescribed limits;

“Habitat” means the type of region or area of natural habitation of any organism or population;

“Natural resources” means natural resources having consumption value, namely land, subsoil, water, flora and fauna;

“Conservation of natural resources” means a system of governmental and social efforts to protect every type of natural resources against abuse, destruction, degradation, which lead to natural resources losing their consumption value;

“Ecological system” or “ecosystem” means an interrelated whole of organisms and their non-living habitat, which interact as a functioning whole;

“Environmental safety” means the security of vital interests and rights of an individual, society and the state against threats arising out of man’s and nature’s impacts on the environment;

“Environmental management” means the administrative management of environmental protection, which includes the organisational structure, planning, responsibility, methods, procedures, processes and resources for the development, introduction, implementation, analysis and sustention of the environmental policy of an enterprise;

“Environmental monitoring” means systematic observation and assessment of the condition of, and the impact on, the environment;

Abbreviations

Acd allergic contact dermatitis

Alm alveolar macrophage

Al action level

Apf assigned protection factor

Atsdr agency for toxic substances and disease registry

Bal bronchoalveolar lavage

Bei biological exposure index

Cca chromated copper arsenate

Ci confidence interval

Cpc chemical protective clothing

Cr chromium

Dpc diphenylcarbazide/diphenylcarbazone

Icda international chromium development association

Abbreviations

Anova		Analysis of variance
Atp		Adenosine triphosphate
Dc		Direct current
Dha		Dehydrogenase activity
Dtpa		Diethylene triamine pentaacetic acid
Dna		Deoxyribonucleicacid
Era		Ecological risk assessment
Gps		Global positioning system
Hmn		Human
Ihl		Inhalation
Ipr		Intraperitoneal
Int		P-iodonitrotetrazolium
Ivn		Intravenous
Jpeg		Joint photographic experts group
Lc50		Lethal concentration 50 percent kill
Lclo		Lowest published lethal concentration
Ld50		Lethal dose 50 percent kill
Ldlo		Lowest published lethal dose
Lsd		Least significant difference
Mus		Mouse
Orl		Oral
Ppm		Parts per million
Rat		Rat
Rbg colour spaces		Red blue and green
Rna		Ribonucleicacid
Tlv	Threshold limit value
Ttc	Triphenyl teterazolium
Twa	Time weighted average
Unep	United nations environmental programme
Usepa	Environnmental protection agency

Introduction

The actuality of the research: when an animal is alive, its skin is soft, flexible, very tough and hard wearing: it has the ability to allow water vapour to pass out, but it will not allow water in. When the skin dies it loses these characteristics: if it is kept wet it rots, and if it is dried it goes hard and brittle.

The process of tanning is to retain the skin's natural properties, to stabilise its structure and at the same time to chemically process it so it will no longer be subject to putrefecation. Thus leather is animal skin that has been treated such that its natural properties are retained.

Skin is made up of many bundles of interwoven protein fibres which are able to move in relation to one another when the skin is alive. When the skin dies, these fibres tend to shrivel and stick together. Essentially, the purpose of tanning is to permanently fix the fibres apart by chemical treatment, and to lubricate them so they can move in relation to one another.

Well tanned leather, therefore, retains the properties of flexibility, toughness and wear. It also continues to 'breathe', allowing water vapour to pass through but remaining reasonably water-proof. It is this characteristic which accounts for the comfort of genuine leather shoes and clothing.

In addition, the process of tanning imparts the advantage of resistance to heat. This is an important factor in many of the uses of leather. In conjunction with chemical processing, the tanner imparts colour, texture and finish to the leather, to enhance its appearance and suit it to today's fashion requirements.

Use of chemical compounds for chrome treatment is not a new phenomenon. A study conducted by m. Ali awan et al., 2003 identified three aqueous oxidants, namely; hydrogen peroxide, sodium hypochlorite and calcium hypochlorite independently in oxidizing chro­mium (iii) containing tannery wastewaters to soluble chromate (cro₄^2-) under alkaline conditions. Among those, hydrogen peroxide was potentially a suitable oxi­dant as it could recover chromate (cro₄^2-) up to 98% (from synthetic cr³+ solution) and 88% (from effluent i). Despite the different experimental conditions (tempera­tures and oxidation time) for all the three oxidants com­plete (100%) recovery could not be achieved. The recov­ery of chromium could help in reducing the possibility of oxidizing cr iii to cr vi (carcinogenic) compound and helps to rescue the financial and environmental cost oc­curred as a result of its discharge [4]. Other kinds of methods like combined system have to be also tested since it might improve the efficiency of recovering chromium from tanning process. In fact experimental conditions like, temperature, ph, time, need to be con­trolled to have more efficient recovery.

Chromium is a common pollutant introduced into natural waters due to the discharge of a variety of industrial wastewaters. On the other hand, chromium based catalysts are also usually employed in various chemical processes, including selective oxidation of hydrocarbons. In all over the world, chromium (cr) is dominant in most of the effluent streams as compared to other heavy metal ions[2]. Caio f etal found that a reduction of more than 1.0 x 10⁵ and 4.0 x 10⁵ fold in total chromium and hexavalent chromium concentrations, respectively, was observed by employing steel wool masses as low as 0.4420 g to 30 ml solutions of wastewater [3].the optimum ph for the precipitating chromium from tannery wastewater is 7.7-8.2 with a lime concentration (2g/100ml) and the effective settling rate was 120min. The bioremoval of cr (vi) using actinomycetes is a suitable mean for reducing the tannery wastewater toxicity. The combination between the chemical precipitation and the biological removal of chromium from tanning wastewater make it meet the environment safely [4].the percent removal of metal ions increases to about 99 % with increasing the mgo dose to some limits. The optimum values of mgo doses were found to be 1.5-3.0 g/l. The ph value ranges are 9.5 to 10 with mgo precipitant and ph of 11.5 to 12 with cao precipitant [5][6]. Combinations of ferric chloride and polymer at different ratio will also results in better removal efficiencies of the metals in the range 84 - 97% for total chromium, 69-90% for zinc and 69­72% for total iron, also less sludge was produced [7]. There are many factors which affect the efficiency of precipitation (ph, nature and concentration of hazardous substances in water, precipitant dosage, temperature, water balance etc.,). In practice, the optimum precipitant and dosage for a particular application are determined by a “trial and errof’ approach using jar test [8]. Moreover ferrous sulphate requires ph =1for complete reduction as compared to sodium metabisulphite which requires a ph of about

A wide range of physical and chemical processes are available for the removal of cr (vi) from effluents. A major drawback with those treatment systems is sludge production, and, high operational cost and some of them are complicated for management. This actually makes the application of these technologies to be limited only in developed countries. In response to this challenge a dif­ferent attempt were undertaken to produce a media which was feasible and cost effective to use by the majority. A research was done s. M. Nomanbhay and k. Palanisamy, 2005 by preparing a new composite bio sorbent which has been done by coating chitosan onto acid treated oil palm shell charcoal (ccab). It is an attractive option because of its cost effective treatment system. Among other low cost absorbent identified chitosan has the highest sorption capacity for several metal ions including chrome. Chromium adsorption was influenced by initial ph, agitation, dose of adsorbent and contact time. For instance at a ph of 5 the media managed to treat 92 % of chromium, which is significant. Further control of these environmental conditions in the laboratory may improve its treatment capacity [5].

A comparison study also conducted by leaching raw tannery effluent through mono and mixed columns (dif­ferent grades) of vermiculite to evaluate their removal efficiency of chromium. The mixed column of vermicu- lite has the highest chromium removal (74.6%) while the mono vermiculite achieved 63.6%. This improvement in chrome removal efficiency is brought by the use of com­bined medias which increase its adsorption capacity. It was also found out that, it could remove cat ions like ca, na, mg and k. Of course high cat ion exchange helps to make the system more efficient [6].

The aim of the research – work out new methods of treatment water from ion chrome. The results obtained for industrial wastewater after the treatment using sodium hydroxide and calcium hydroxide combination are in par with the synthetic sample results. The sodium hydroxide and calcium hydroxide combination shows the better removal efficiency with less volume of sludge compared to other precipitating agents. Experiments on industrial wastewater show that, removal efficiency is in par with the efficiency obtained for synthetic sample experiments, except for ferric chloride. The cr(iii) removal efficiency using calcium hydroxide and sodium hydroxide combination was found to be 99.7% and with volume of sludge produced as 7 ml/l. On this basis one can conclude that one of chemical promising development in the chemical industry grown .

The object of course work is purification of sewage water from cr (vi) in leather industry.

The subject of the course work is deep sewage treatment conventional chrome tanning in leather production for the purpose of turnaround water supply.